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freebsd-src/contrib/gcc/fold-const.c
David E. O'Brien 1952e2e1c1 Enlist the FreeBSD-CURRENT users as testers of what is to become Gcc 3.1.0. 
These bits are taken from the FSF anoncvs repo on 1-Feb-2002 08:20 PST.
2002-02-01 18:16:02 +00:00

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/* Fold a constant sub-tree into a single node for C-compiler
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
/*@@ This file should be rewritten to use an arbitrary precision
@@ representation for "struct tree_int_cst" and "struct tree_real_cst".
@@ Perhaps the routines could also be used for bc/dc, and made a lib.
@@ The routines that translate from the ap rep should
@@ warn if precision et. al. is lost.
@@ This would also make life easier when this technology is used
@@ for cross-compilers. */
/* The entry points in this file are fold, size_int_wide, size_binop
and force_fit_type.
fold takes a tree as argument and returns a simplified tree.
size_binop takes a tree code for an arithmetic operation
and two operands that are trees, and produces a tree for the
result, assuming the type comes from `sizetype'.
size_int takes an integer value, and creates a tree constant
with type from `sizetype'.
force_fit_type takes a constant and prior overflow indicator, and
forces the value to fit the type. It returns an overflow indicator. */
#include "config.h"
#include "system.h"
#include "flags.h"
#include "tree.h"
#include "rtl.h"
#include "expr.h"
#include "tm_p.h"
#include "toplev.h"
#include "ggc.h"
#include "hashtab.h"
static void encode PARAMS ((HOST_WIDE_INT *,
unsigned HOST_WIDE_INT,
HOST_WIDE_INT));
static void decode PARAMS ((HOST_WIDE_INT *,
unsigned HOST_WIDE_INT *,
HOST_WIDE_INT *));
#ifndef REAL_ARITHMETIC
static void exact_real_inverse_1 PARAMS ((PTR));
#endif
static tree negate_expr PARAMS ((tree));
static tree split_tree PARAMS ((tree, enum tree_code, tree *, tree *,
int));
static tree associate_trees PARAMS ((tree, tree, enum tree_code, tree));
static tree int_const_binop PARAMS ((enum tree_code, tree, tree, int));
static void const_binop_1 PARAMS ((PTR));
static tree const_binop PARAMS ((enum tree_code, tree, tree, int));
static hashval_t size_htab_hash PARAMS ((const void *));
static int size_htab_eq PARAMS ((const void *, const void *));
static void fold_convert_1 PARAMS ((PTR));
static tree fold_convert PARAMS ((tree, tree));
static enum tree_code invert_tree_comparison PARAMS ((enum tree_code));
static enum tree_code swap_tree_comparison PARAMS ((enum tree_code));
static int truth_value_p PARAMS ((enum tree_code));
static int operand_equal_for_comparison_p PARAMS ((tree, tree, tree));
static int twoval_comparison_p PARAMS ((tree, tree *, tree *, int *));
static tree eval_subst PARAMS ((tree, tree, tree, tree, tree));
static tree omit_one_operand PARAMS ((tree, tree, tree));
static tree pedantic_omit_one_operand PARAMS ((tree, tree, tree));
static tree distribute_bit_expr PARAMS ((enum tree_code, tree, tree, tree));
static tree make_bit_field_ref PARAMS ((tree, tree, int, int, int));
static tree optimize_bit_field_compare PARAMS ((enum tree_code, tree,
tree, tree));
static tree decode_field_reference PARAMS ((tree, HOST_WIDE_INT *,
HOST_WIDE_INT *,
enum machine_mode *, int *,
int *, tree *, tree *));
static int all_ones_mask_p PARAMS ((tree, int));
static int simple_operand_p PARAMS ((tree));
static tree range_binop PARAMS ((enum tree_code, tree, tree, int,
tree, int));
static tree make_range PARAMS ((tree, int *, tree *, tree *));
static tree build_range_check PARAMS ((tree, tree, int, tree, tree));
static int merge_ranges PARAMS ((int *, tree *, tree *, int, tree, tree,
int, tree, tree));
static tree fold_range_test PARAMS ((tree));
static tree unextend PARAMS ((tree, int, int, tree));
static tree fold_truthop PARAMS ((enum tree_code, tree, tree, tree));
static tree optimize_minmax_comparison PARAMS ((tree));
static tree extract_muldiv PARAMS ((tree, tree, enum tree_code, tree));
static tree strip_compound_expr PARAMS ((tree, tree));
static int multiple_of_p PARAMS ((tree, tree, tree));
static tree constant_boolean_node PARAMS ((int, tree));
static int count_cond PARAMS ((tree, int));
static tree fold_binary_op_with_conditional_arg
PARAMS ((enum tree_code, tree, tree, tree, int));
#ifndef BRANCH_COST
#define BRANCH_COST 1
#endif
#if defined(HOST_EBCDIC)
/* bit 8 is significant in EBCDIC */
#define CHARMASK 0xff
#else
#define CHARMASK 0x7f
#endif
/* We know that A1 + B1 = SUM1, using 2's complement arithmetic and ignoring
overflow. Suppose A, B and SUM have the same respective signs as A1, B1,
and SUM1. Then this yields nonzero if overflow occurred during the
addition.
Overflow occurs if A and B have the same sign, but A and SUM differ in
sign. Use `^' to test whether signs differ, and `< 0' to isolate the
sign. */
#define OVERFLOW_SUM_SIGN(a, b, sum) ((~((a) ^ (b)) & ((a) ^ (sum))) < 0)
/* To do constant folding on INTEGER_CST nodes requires two-word arithmetic.
We do that by representing the two-word integer in 4 words, with only
HOST_BITS_PER_WIDE_INT / 2 bits stored in each word, as a positive
number. The value of the word is LOWPART + HIGHPART * BASE. */
#define LOWPART(x) \
((x) & (((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)) - 1))
#define HIGHPART(x) \
((unsigned HOST_WIDE_INT) (x) >> HOST_BITS_PER_WIDE_INT / 2)
#define BASE ((unsigned HOST_WIDE_INT) 1 << HOST_BITS_PER_WIDE_INT / 2)
/* Unpack a two-word integer into 4 words.
LOW and HI are the integer, as two `HOST_WIDE_INT' pieces.
WORDS points to the array of HOST_WIDE_INTs. */
static void
encode (words, low, hi)
HOST_WIDE_INT *words;
unsigned HOST_WIDE_INT low;
HOST_WIDE_INT hi;
{
words[0] = LOWPART (low);
words[1] = HIGHPART (low);
words[2] = LOWPART (hi);
words[3] = HIGHPART (hi);
}
/* Pack an array of 4 words into a two-word integer.
WORDS points to the array of words.
The integer is stored into *LOW and *HI as two `HOST_WIDE_INT' pieces. */
static void
decode (words, low, hi)
HOST_WIDE_INT *words;
unsigned HOST_WIDE_INT *low;
HOST_WIDE_INT *hi;
{
*low = words[0] + words[1] * BASE;
*hi = words[2] + words[3] * BASE;
}
/* Make the integer constant T valid for its type by setting to 0 or 1 all
the bits in the constant that don't belong in the type.
Return 1 if a signed overflow occurs, 0 otherwise. If OVERFLOW is
nonzero, a signed overflow has already occurred in calculating T, so
propagate it.
Make the real constant T valid for its type by calling CHECK_FLOAT_VALUE,
if it exists. */
int
force_fit_type (t, overflow)
tree t;
int overflow;
{
unsigned HOST_WIDE_INT low;
HOST_WIDE_INT high;
unsigned int prec;
if (TREE_CODE (t) == REAL_CST)
{
#ifdef CHECK_FLOAT_VALUE
CHECK_FLOAT_VALUE (TYPE_MODE (TREE_TYPE (t)), TREE_REAL_CST (t),
overflow);
#endif
return overflow;
}
else if (TREE_CODE (t) != INTEGER_CST)
return overflow;
low = TREE_INT_CST_LOW (t);
high = TREE_INT_CST_HIGH (t);
if (POINTER_TYPE_P (TREE_TYPE (t)))
prec = POINTER_SIZE;
else
prec = TYPE_PRECISION (TREE_TYPE (t));
/* First clear all bits that are beyond the type's precision. */
if (prec == 2 * HOST_BITS_PER_WIDE_INT)
;
else if (prec > HOST_BITS_PER_WIDE_INT)
TREE_INT_CST_HIGH (t)
&= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
else
{
TREE_INT_CST_HIGH (t) = 0;
if (prec < HOST_BITS_PER_WIDE_INT)
TREE_INT_CST_LOW (t) &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
}
/* Unsigned types do not suffer sign extension or overflow unless they
are a sizetype. */
if (TREE_UNSIGNED (TREE_TYPE (t))
&& ! (TREE_CODE (TREE_TYPE (t)) == INTEGER_TYPE
&& TYPE_IS_SIZETYPE (TREE_TYPE (t))))
return overflow;
/* If the value's sign bit is set, extend the sign. */
if (prec != 2 * HOST_BITS_PER_WIDE_INT
&& (prec > HOST_BITS_PER_WIDE_INT
? 0 != (TREE_INT_CST_HIGH (t)
& ((HOST_WIDE_INT) 1
<< (prec - HOST_BITS_PER_WIDE_INT - 1)))
: 0 != (TREE_INT_CST_LOW (t)
& ((unsigned HOST_WIDE_INT) 1 << (prec - 1)))))
{
/* Value is negative:
set to 1 all the bits that are outside this type's precision. */
if (prec > HOST_BITS_PER_WIDE_INT)
TREE_INT_CST_HIGH (t)
|= ((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
else
{
TREE_INT_CST_HIGH (t) = -1;
if (prec < HOST_BITS_PER_WIDE_INT)
TREE_INT_CST_LOW (t) |= ((unsigned HOST_WIDE_INT) (-1) << prec);
}
}
/* Return nonzero if signed overflow occurred. */
return
((overflow | (low ^ TREE_INT_CST_LOW (t)) | (high ^ TREE_INT_CST_HIGH (t)))
!= 0);
}
/* Add two doubleword integers with doubleword result.
Each argument is given as two `HOST_WIDE_INT' pieces.
One argument is L1 and H1; the other, L2 and H2.
The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
int
add_double (l1, h1, l2, h2, lv, hv)
unsigned HOST_WIDE_INT l1, l2;
HOST_WIDE_INT h1, h2;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
{
unsigned HOST_WIDE_INT l;
HOST_WIDE_INT h;
l = l1 + l2;
h = h1 + h2 + (l < l1);
*lv = l;
*hv = h;
return OVERFLOW_SUM_SIGN (h1, h2, h);
}
/* Negate a doubleword integer with doubleword result.
Return nonzero if the operation overflows, assuming it's signed.
The argument is given as two `HOST_WIDE_INT' pieces in L1 and H1.
The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
int
neg_double (l1, h1, lv, hv)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
{
if (l1 == 0)
{
*lv = 0;
*hv = - h1;
return (*hv & h1) < 0;
}
else
{
*lv = -l1;
*hv = ~h1;
return 0;
}
}
/* Multiply two doubleword integers with doubleword result.
Return nonzero if the operation overflows, assuming it's signed.
Each argument is given as two `HOST_WIDE_INT' pieces.
One argument is L1 and H1; the other, L2 and H2.
The value is stored as two `HOST_WIDE_INT' pieces in *LV and *HV. */
int
mul_double (l1, h1, l2, h2, lv, hv)
unsigned HOST_WIDE_INT l1, l2;
HOST_WIDE_INT h1, h2;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
{
HOST_WIDE_INT arg1[4];
HOST_WIDE_INT arg2[4];
HOST_WIDE_INT prod[4 * 2];
unsigned HOST_WIDE_INT carry;
int i, j, k;
unsigned HOST_WIDE_INT toplow, neglow;
HOST_WIDE_INT tophigh, neghigh;
encode (arg1, l1, h1);
encode (arg2, l2, h2);
memset ((char *) prod, 0, sizeof prod);
for (i = 0; i < 4; i++)
{
carry = 0;
for (j = 0; j < 4; j++)
{
k = i + j;
/* This product is <= 0xFFFE0001, the sum <= 0xFFFF0000. */
carry += arg1[i] * arg2[j];
/* Since prod[p] < 0xFFFF, this sum <= 0xFFFFFFFF. */
carry += prod[k];
prod[k] = LOWPART (carry);
carry = HIGHPART (carry);
}
prod[i + 4] = carry;
}
decode (prod, lv, hv); /* This ignores prod[4] through prod[4*2-1] */
/* Check for overflow by calculating the top half of the answer in full;
it should agree with the low half's sign bit. */
decode (prod + 4, &toplow, &tophigh);
if (h1 < 0)
{
neg_double (l2, h2, &neglow, &neghigh);
add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
}
if (h2 < 0)
{
neg_double (l1, h1, &neglow, &neghigh);
add_double (neglow, neghigh, toplow, tophigh, &toplow, &tophigh);
}
return (*hv < 0 ? ~(toplow & tophigh) : toplow | tophigh) != 0;
}
/* Shift the doubleword integer in L1, H1 left by COUNT places
keeping only PREC bits of result.
Shift right if COUNT is negative.
ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
lshift_double (l1, h1, count, prec, lv, hv, arith)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1, count;
unsigned int prec;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
int arith;
{
unsigned HOST_WIDE_INT signmask;
if (count < 0)
{
rshift_double (l1, h1, -count, prec, lv, hv, arith);
return;
}
#ifdef SHIFT_COUNT_TRUNCATED
if (SHIFT_COUNT_TRUNCATED)
count %= prec;
#endif
if (count >= 2 * HOST_BITS_PER_WIDE_INT)
{
/* Shifting by the host word size is undefined according to the
ANSI standard, so we must handle this as a special case. */
*hv = 0;
*lv = 0;
}
else if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = l1 << (count - HOST_BITS_PER_WIDE_INT);
*lv = 0;
}
else
{
*hv = (((unsigned HOST_WIDE_INT) h1 << count)
| (l1 >> (HOST_BITS_PER_WIDE_INT - count - 1) >> 1));
*lv = l1 << count;
}
/* Sign extend all bits that are beyond the precision. */
signmask = -((prec > HOST_BITS_PER_WIDE_INT
? (*hv >> (prec - HOST_BITS_PER_WIDE_INT - 1))
: (*lv >> (prec - 1))) & 1);
if (prec >= 2 * HOST_BITS_PER_WIDE_INT)
;
else if (prec >= HOST_BITS_PER_WIDE_INT)
{
*hv &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
*hv |= signmask << (prec - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = signmask;
*lv &= ~((unsigned HOST_WIDE_INT) (-1) << prec);
*lv |= signmask << prec;
}
}
/* Shift the doubleword integer in L1, H1 right by COUNT places
keeping only PREC bits of result. COUNT must be positive.
ARITH nonzero specifies arithmetic shifting; otherwise use logical shift.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
rshift_double (l1, h1, count, prec, lv, hv, arith)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1, count;
unsigned int prec;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
int arith;
{
unsigned HOST_WIDE_INT signmask;
signmask = (arith
? -((unsigned HOST_WIDE_INT) h1 >> (HOST_BITS_PER_WIDE_INT - 1))
: 0);
#ifdef SHIFT_COUNT_TRUNCATED
if (SHIFT_COUNT_TRUNCATED)
count %= prec;
#endif
if (count >= 2 * HOST_BITS_PER_WIDE_INT)
{
/* Shifting by the host word size is undefined according to the
ANSI standard, so we must handle this as a special case. */
*hv = 0;
*lv = 0;
}
else if (count >= HOST_BITS_PER_WIDE_INT)
{
*hv = 0;
*lv = (unsigned HOST_WIDE_INT) h1 >> (count - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = (unsigned HOST_WIDE_INT) h1 >> count;
*lv = ((l1 >> count)
| ((unsigned HOST_WIDE_INT) h1 << (HOST_BITS_PER_WIDE_INT - count - 1) << 1));
}
/* Zero / sign extend all bits that are beyond the precision. */
if (count >= (HOST_WIDE_INT)prec)
{
*hv = signmask;
*lv = signmask;
}
else if ((prec - count) >= 2 * HOST_BITS_PER_WIDE_INT)
;
else if ((prec - count) >= HOST_BITS_PER_WIDE_INT)
{
*hv &= ~((HOST_WIDE_INT) (-1) << (prec - count - HOST_BITS_PER_WIDE_INT));
*hv |= signmask << (prec - count - HOST_BITS_PER_WIDE_INT);
}
else
{
*hv = signmask;
*lv &= ~((unsigned HOST_WIDE_INT) (-1) << (prec - count));
*lv |= signmask << (prec - count);
}
}
/* Rotate the doubleword integer in L1, H1 left by COUNT places
keeping only PREC bits of result.
Rotate right if COUNT is negative.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
lrotate_double (l1, h1, count, prec, lv, hv)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1, count;
unsigned int prec;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
{
unsigned HOST_WIDE_INT s1l, s2l;
HOST_WIDE_INT s1h, s2h;
count %= prec;
if (count < 0)
count += prec;
lshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
rshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
*lv = s1l | s2l;
*hv = s1h | s2h;
}
/* Rotate the doubleword integer in L1, H1 left by COUNT places
keeping only PREC bits of result. COUNT must be positive.
Store the value as two `HOST_WIDE_INT' pieces in *LV and *HV. */
void
rrotate_double (l1, h1, count, prec, lv, hv)
unsigned HOST_WIDE_INT l1;
HOST_WIDE_INT h1, count;
unsigned int prec;
unsigned HOST_WIDE_INT *lv;
HOST_WIDE_INT *hv;
{
unsigned HOST_WIDE_INT s1l, s2l;
HOST_WIDE_INT s1h, s2h;
count %= prec;
if (count < 0)
count += prec;
rshift_double (l1, h1, count, prec, &s1l, &s1h, 0);
lshift_double (l1, h1, prec - count, prec, &s2l, &s2h, 0);
*lv = s1l | s2l;
*hv = s1h | s2h;
}
/* Divide doubleword integer LNUM, HNUM by doubleword integer LDEN, HDEN
for a quotient (stored in *LQUO, *HQUO) and remainder (in *LREM, *HREM).
CODE is a tree code for a kind of division, one of
TRUNC_DIV_EXPR, FLOOR_DIV_EXPR, CEIL_DIV_EXPR, ROUND_DIV_EXPR
or EXACT_DIV_EXPR
It controls how the quotient is rounded to an integer.
Return nonzero if the operation overflows.
UNS nonzero says do unsigned division. */
int
div_and_round_double (code, uns,
lnum_orig, hnum_orig, lden_orig, hden_orig,
lquo, hquo, lrem, hrem)
enum tree_code code;
int uns;
unsigned HOST_WIDE_INT lnum_orig; /* num == numerator == dividend */
HOST_WIDE_INT hnum_orig;
unsigned HOST_WIDE_INT lden_orig; /* den == denominator == divisor */
HOST_WIDE_INT hden_orig;
unsigned HOST_WIDE_INT *lquo, *lrem;
HOST_WIDE_INT *hquo, *hrem;
{
int quo_neg = 0;
HOST_WIDE_INT num[4 + 1]; /* extra element for scaling. */
HOST_WIDE_INT den[4], quo[4];
int i, j;
unsigned HOST_WIDE_INT work;
unsigned HOST_WIDE_INT carry = 0;
unsigned HOST_WIDE_INT lnum = lnum_orig;
HOST_WIDE_INT hnum = hnum_orig;
unsigned HOST_WIDE_INT lden = lden_orig;
HOST_WIDE_INT hden = hden_orig;
int overflow = 0;
if (hden == 0 && lden == 0)
overflow = 1, lden = 1;
/* calculate quotient sign and convert operands to unsigned. */
if (!uns)
{
if (hnum < 0)
{
quo_neg = ~ quo_neg;
/* (minimum integer) / (-1) is the only overflow case. */
if (neg_double (lnum, hnum, &lnum, &hnum)
&& ((HOST_WIDE_INT) lden & hden) == -1)
overflow = 1;
}
if (hden < 0)
{
quo_neg = ~ quo_neg;
neg_double (lden, hden, &lden, &hden);
}
}
if (hnum == 0 && hden == 0)
{ /* single precision */
*hquo = *hrem = 0;
/* This unsigned division rounds toward zero. */
*lquo = lnum / lden;
goto finish_up;
}
if (hnum == 0)
{ /* trivial case: dividend < divisor */
/* hden != 0 already checked. */
*hquo = *lquo = 0;
*hrem = hnum;
*lrem = lnum;
goto finish_up;
}
memset ((char *) quo, 0, sizeof quo);
memset ((char *) num, 0, sizeof num); /* to zero 9th element */
memset ((char *) den, 0, sizeof den);
encode (num, lnum, hnum);
encode (den, lden, hden);
/* Special code for when the divisor < BASE. */
if (hden == 0 && lden < (unsigned HOST_WIDE_INT) BASE)
{
/* hnum != 0 already checked. */
for (i = 4 - 1; i >= 0; i--)
{
work = num[i] + carry * BASE;
quo[i] = work / lden;
carry = work % lden;
}
}
else
{
/* Full double precision division,
with thanks to Don Knuth's "Seminumerical Algorithms". */
int num_hi_sig, den_hi_sig;
unsigned HOST_WIDE_INT quo_est, scale;
/* Find the highest non-zero divisor digit. */
for (i = 4 - 1;; i--)
if (den[i] != 0)
{
den_hi_sig = i;
break;
}
/* Insure that the first digit of the divisor is at least BASE/2.
This is required by the quotient digit estimation algorithm. */
scale = BASE / (den[den_hi_sig] + 1);
if (scale > 1)
{ /* scale divisor and dividend */
carry = 0;
for (i = 0; i <= 4 - 1; i++)
{
work = (num[i] * scale) + carry;
num[i] = LOWPART (work);
carry = HIGHPART (work);
}
num[4] = carry;
carry = 0;
for (i = 0; i <= 4 - 1; i++)
{
work = (den[i] * scale) + carry;
den[i] = LOWPART (work);
carry = HIGHPART (work);
if (den[i] != 0) den_hi_sig = i;
}
}
num_hi_sig = 4;
/* Main loop */
for (i = num_hi_sig - den_hi_sig - 1; i >= 0; i--)
{
/* Guess the next quotient digit, quo_est, by dividing the first
two remaining dividend digits by the high order quotient digit.
quo_est is never low and is at most 2 high. */
unsigned HOST_WIDE_INT tmp;
num_hi_sig = i + den_hi_sig + 1;
work = num[num_hi_sig] * BASE + num[num_hi_sig - 1];
if (num[num_hi_sig] != den[den_hi_sig])
quo_est = work / den[den_hi_sig];
else
quo_est = BASE - 1;
/* Refine quo_est so it's usually correct, and at most one high. */
tmp = work - quo_est * den[den_hi_sig];
if (tmp < BASE
&& (den[den_hi_sig - 1] * quo_est
> (tmp * BASE + num[num_hi_sig - 2])))
quo_est--;
/* Try QUO_EST as the quotient digit, by multiplying the
divisor by QUO_EST and subtracting from the remaining dividend.
Keep in mind that QUO_EST is the I - 1st digit. */
carry = 0;
for (j = 0; j <= den_hi_sig; j++)
{
work = quo_est * den[j] + carry;
carry = HIGHPART (work);
work = num[i + j] - LOWPART (work);
num[i + j] = LOWPART (work);
carry += HIGHPART (work) != 0;
}
/* If quo_est was high by one, then num[i] went negative and
we need to correct things. */
if (num[num_hi_sig] < carry)
{
quo_est--;
carry = 0; /* add divisor back in */
for (j = 0; j <= den_hi_sig; j++)
{
work = num[i + j] + den[j] + carry;
carry = HIGHPART (work);
num[i + j] = LOWPART (work);
}
num [num_hi_sig] += carry;
}
/* Store the quotient digit. */
quo[i] = quo_est;
}
}
decode (quo, lquo, hquo);
finish_up:
/* if result is negative, make it so. */
if (quo_neg)
neg_double (*lquo, *hquo, lquo, hquo);
/* compute trial remainder: rem = num - (quo * den) */
mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
neg_double (*lrem, *hrem, lrem, hrem);
add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
switch (code)
{
case TRUNC_DIV_EXPR:
case TRUNC_MOD_EXPR: /* round toward zero */
case EXACT_DIV_EXPR: /* for this one, it shouldn't matter */
return overflow;
case FLOOR_DIV_EXPR:
case FLOOR_MOD_EXPR: /* round toward negative infinity */
if (quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio < 0 && rem != 0 */
{
/* quo = quo - 1; */
add_double (*lquo, *hquo, (HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1,
lquo, hquo);
}
else
return overflow;
break;
case CEIL_DIV_EXPR:
case CEIL_MOD_EXPR: /* round toward positive infinity */
if (!quo_neg && (*lrem != 0 || *hrem != 0)) /* ratio > 0 && rem != 0 */
{
add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
lquo, hquo);
}
else
return overflow;
break;
case ROUND_DIV_EXPR:
case ROUND_MOD_EXPR: /* round to closest integer */
{
unsigned HOST_WIDE_INT labs_rem = *lrem;
HOST_WIDE_INT habs_rem = *hrem;
unsigned HOST_WIDE_INT labs_den = lden, ltwice;
HOST_WIDE_INT habs_den = hden, htwice;
/* Get absolute values */
if (*hrem < 0)
neg_double (*lrem, *hrem, &labs_rem, &habs_rem);
if (hden < 0)
neg_double (lden, hden, &labs_den, &habs_den);
/* If (2 * abs (lrem) >= abs (lden)) */
mul_double ((HOST_WIDE_INT) 2, (HOST_WIDE_INT) 0,
labs_rem, habs_rem, &ltwice, &htwice);
if (((unsigned HOST_WIDE_INT) habs_den
< (unsigned HOST_WIDE_INT) htwice)
|| (((unsigned HOST_WIDE_INT) habs_den
== (unsigned HOST_WIDE_INT) htwice)
&& (labs_den < ltwice)))
{
if (*hquo < 0)
/* quo = quo - 1; */
add_double (*lquo, *hquo,
(HOST_WIDE_INT) -1, (HOST_WIDE_INT) -1, lquo, hquo);
else
/* quo = quo + 1; */
add_double (*lquo, *hquo, (HOST_WIDE_INT) 1, (HOST_WIDE_INT) 0,
lquo, hquo);
}
else
return overflow;
}
break;
default:
abort ();
}
/* compute true remainder: rem = num - (quo * den) */
mul_double (*lquo, *hquo, lden_orig, hden_orig, lrem, hrem);
neg_double (*lrem, *hrem, lrem, hrem);
add_double (lnum_orig, hnum_orig, *lrem, *hrem, lrem, hrem);
return overflow;
}
#ifndef REAL_ARITHMETIC
/* Effectively truncate a real value to represent the nearest possible value
in a narrower mode. The result is actually represented in the same data
type as the argument, but its value is usually different.
A trap may occur during the FP operations and it is the responsibility
of the calling function to have a handler established. */
REAL_VALUE_TYPE
real_value_truncate (mode, arg)
enum machine_mode mode;
REAL_VALUE_TYPE arg;
{
return REAL_VALUE_TRUNCATE (mode, arg);
}
#if TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
/* Check for infinity in an IEEE double precision number. */
int
target_isinf (x)
REAL_VALUE_TYPE x;
{
/* The IEEE 64-bit double format. */
union {
REAL_VALUE_TYPE d;
struct {
unsigned sign : 1;
unsigned exponent : 11;
unsigned mantissa1 : 20;
unsigned mantissa2 : 32;
} little_endian;
struct {
unsigned mantissa2 : 32;
unsigned mantissa1 : 20;
unsigned exponent : 11;
unsigned sign : 1;
} big_endian;
} u;
u.d = dconstm1;
if (u.big_endian.sign == 1)
{
u.d = x;
return (u.big_endian.exponent == 2047
&& u.big_endian.mantissa1 == 0
&& u.big_endian.mantissa2 == 0);
}
else
{
u.d = x;
return (u.little_endian.exponent == 2047
&& u.little_endian.mantissa1 == 0
&& u.little_endian.mantissa2 == 0);
}
}
/* Check whether an IEEE double precision number is a NaN. */
int
target_isnan (x)
REAL_VALUE_TYPE x;
{
/* The IEEE 64-bit double format. */
union {
REAL_VALUE_TYPE d;
struct {
unsigned sign : 1;
unsigned exponent : 11;
unsigned mantissa1 : 20;
unsigned mantissa2 : 32;
} little_endian;
struct {
unsigned mantissa2 : 32;
unsigned mantissa1 : 20;
unsigned exponent : 11;
unsigned sign : 1;
} big_endian;
} u;
u.d = dconstm1;
if (u.big_endian.sign == 1)
{
u.d = x;
return (u.big_endian.exponent == 2047
&& (u.big_endian.mantissa1 != 0
|| u.big_endian.mantissa2 != 0));
}
else
{
u.d = x;
return (u.little_endian.exponent == 2047
&& (u.little_endian.mantissa1 != 0
|| u.little_endian.mantissa2 != 0));
}
}
/* Check for a negative IEEE double precision number. */
int
target_negative (x)
REAL_VALUE_TYPE x;
{
/* The IEEE 64-bit double format. */
union {
REAL_VALUE_TYPE d;
struct {
unsigned sign : 1;
unsigned exponent : 11;
unsigned mantissa1 : 20;
unsigned mantissa2 : 32;
} little_endian;
struct {
unsigned mantissa2 : 32;
unsigned mantissa1 : 20;
unsigned exponent : 11;
unsigned sign : 1;
} big_endian;
} u;
u.d = dconstm1;
if (u.big_endian.sign == 1)
{
u.d = x;
return u.big_endian.sign;
}
else
{
u.d = x;
return u.little_endian.sign;
}
}
#else /* Target not IEEE */
/* Let's assume other float formats don't have infinity.
(This can be overridden by redefining REAL_VALUE_ISINF.) */
int
target_isinf (x)
REAL_VALUE_TYPE x ATTRIBUTE_UNUSED;
{
return 0;
}
/* Let's assume other float formats don't have NaNs.
(This can be overridden by redefining REAL_VALUE_ISNAN.) */
int
target_isnan (x)
REAL_VALUE_TYPE x ATTRIBUTE_UNUSED;
{
return 0;
}
/* Let's assume other float formats don't have minus zero.
(This can be overridden by redefining REAL_VALUE_NEGATIVE.) */
int
target_negative (x)
REAL_VALUE_TYPE x;
{
return x < 0;
}
#endif /* Target not IEEE */
/* Try to change R into its exact multiplicative inverse in machine mode
MODE. Return nonzero function value if successful. */
struct exact_real_inverse_args
{
REAL_VALUE_TYPE *r;
enum machine_mode mode;
int success;
};
static void
exact_real_inverse_1 (p)
PTR p;
{
struct exact_real_inverse_args *args =
(struct exact_real_inverse_args *) p;
enum machine_mode mode = args->mode;
REAL_VALUE_TYPE *r = args->r;
union
{
double d;
unsigned short i[4];
}
x, t, y;
#ifdef CHECK_FLOAT_VALUE
int i;
#endif
/* Set array index to the less significant bits in the unions, depending
on the endian-ness of the host doubles. */
#if HOST_FLOAT_FORMAT == VAX_FLOAT_FORMAT \
|| HOST_FLOAT_FORMAT == IBM_FLOAT_FORMAT
# define K 2
#else
# define K (2 * HOST_FLOAT_WORDS_BIG_ENDIAN)
#endif
/* Domain check the argument. */
x.d = *r;
if (x.d == 0.0)
goto fail;
#ifdef REAL_INFINITY
if (REAL_VALUE_ISINF (x.d) || REAL_VALUE_ISNAN (x.d))
goto fail;
#endif
/* Compute the reciprocal and check for numerical exactness.
It is unnecessary to check all the significand bits to determine
whether X is a power of 2. If X is not, then it is impossible for
the bottom half significand of both X and 1/X to be all zero bits.
Hence we ignore the data structure of the top half and examine only
the low order bits of the two significands. */
t.d = 1.0 / x.d;
if (x.i[K] != 0 || x.i[K + 1] != 0 || t.i[K] != 0 || t.i[K + 1] != 0)
goto fail;
/* Truncate to the required mode and range-check the result. */
y.d = REAL_VALUE_TRUNCATE (mode, t.d);
#ifdef CHECK_FLOAT_VALUE
i = 0;
if (CHECK_FLOAT_VALUE (mode, y.d, i))
goto fail;
#endif
/* Fail if truncation changed the value. */
if (y.d != t.d || y.d == 0.0)
goto fail;
#ifdef REAL_INFINITY
if (REAL_VALUE_ISINF (y.d) || REAL_VALUE_ISNAN (y.d))
goto fail;
#endif
/* Output the reciprocal and return success flag. */
*r = y.d;
args->success = 1;
return;
fail:
args->success = 0;
return;
#undef K
}
int
exact_real_inverse (mode, r)
enum machine_mode mode;
REAL_VALUE_TYPE *r;
{
struct exact_real_inverse_args args;
/* Disable if insufficient information on the data structure. */
#if HOST_FLOAT_FORMAT == UNKNOWN_FLOAT_FORMAT
return 0;
#endif
/* Usually disable if bounds checks are not reliable. */
if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT) && !flag_pretend_float)
return 0;
args.mode = mode;
args.r = r;
if (do_float_handler (exact_real_inverse_1, (PTR) &args))
return args.success;
return 0;
}
/* Convert C99 hexadecimal floating point string constant S. Return
real value type in mode MODE. This function uses the host computer's
floating point arithmetic when there is no REAL_ARITHMETIC. */
REAL_VALUE_TYPE
real_hex_to_f (s, mode)
const char *s;
enum machine_mode mode;
{
REAL_VALUE_TYPE ip;
const char *p = s;
unsigned HOST_WIDE_INT low, high;
int shcount, nrmcount, k;
int sign, expsign, isfloat;
int lost = 0;/* Nonzero low order bits shifted out and discarded. */
int frexpon = 0; /* Bits after the decimal point. */
int expon = 0; /* Value of exponent. */
int decpt = 0; /* How many decimal points. */
int gotp = 0; /* How many P's. */
char c;
isfloat = 0;
expsign = 1;
ip = 0.0;
while (*p == ' ' || *p == '\t')
++p;
/* Sign, if any, comes first. */
sign = 1;
if (*p == '-')
{
sign = -1;
++p;
}
/* The string is supposed to start with 0x or 0X . */
if (*p == '0')
{
++p;
if (*p == 'x' || *p == 'X')
++p;
else
abort ();
}
else
abort ();
while (*p == '0')
++p;
high = 0;
low = 0;
shcount = 0;
while ((c = *p) != '\0')
{
if (ISXDIGIT (c))
{
k = hex_value (c & CHARMASK);
if ((high & 0xf0000000) == 0)
{
high = (high << 4) + ((low >> 28) & 15);
low = (low << 4) + k;
shcount += 4;
if (decpt)
frexpon += 4;
}
else
{
/* Record nonzero lost bits. */
lost |= k;
if (! decpt)
frexpon -= 4;
}
++p;
}
else if (c == '.')
{
++decpt;
++p;
}
else if (c == 'p' || c == 'P')
{
++gotp;
++p;
/* Sign of exponent. */
if (*p == '-')
{
expsign = -1;
++p;
}
/* Value of exponent.
The exponent field is a decimal integer. */
while (ISDIGIT (*p))
{
k = (*p++ & CHARMASK) - '0';
expon = 10 * expon + k;
}
expon *= expsign;
/* F suffix is ambiguous in the significand part
so it must appear after the decimal exponent field. */
if (*p == 'f' || *p == 'F')
{
isfloat = 1;
++p;
break;
}
}
else if (c == 'l' || c == 'L')
{
++p;
break;
}
else
break;
}
/* Abort if last character read was not legitimate. */
c = *p;
if ((c != '\0' && c != ' ' && c != '\n' && c != '\r') || (decpt > 1))
abort ();
/* There must be either one decimal point or one p. */
if (decpt == 0 && gotp == 0)
abort ();
shcount -= 4;
if (high == 0 && low == 0)
return dconst0;
/* Normalize. */
nrmcount = 0;
if (high == 0)
{
high = low;
low = 0;
nrmcount += 32;
}
/* Leave a high guard bit for carry-out. */
if ((high & 0x80000000) != 0)
{
lost |= low & 1;
low = (low >> 1) | (high << 31);
high = high >> 1;
nrmcount -= 1;
}
if ((high & 0xffff8000) == 0)
{
high = (high << 16) + ((low >> 16) & 0xffff);
low = low << 16;
nrmcount += 16;
}
while ((high & 0xc0000000) == 0)
{
high = (high << 1) + ((low >> 31) & 1);
low = low << 1;
nrmcount += 1;
}
if (isfloat || GET_MODE_SIZE (mode) == UNITS_PER_WORD)
{
/* Keep 24 bits precision, bits 0x7fffff80.
Rounding bit is 0x40. */
lost = lost | low | (high & 0x3f);
low = 0;
if (high & 0x40)
{
if ((high & 0x80) || lost)
high += 0x40;
}
high &= 0xffffff80;
}
else
{
/* We need real.c to do long double formats, so here default
to double precision. */
#if HOST_FLOAT_FORMAT == IEEE_FLOAT_FORMAT
/* IEEE double.
Keep 53 bits precision, bits 0x7fffffff fffffc00.
Rounding bit is low word 0x200. */
lost = lost | (low & 0x1ff);
if (low & 0x200)
{
if ((low & 0x400) || lost)
{
low = (low + 0x200) & 0xfffffc00;
if (low == 0)
high += 1;
}
}
low &= 0xfffffc00;
#else
/* Assume it's a VAX with 56-bit significand,
bits 0x7fffffff ffffff80. */
lost = lost | (low & 0x7f);
if (low & 0x40)
{
if ((low & 0x80) || lost)
{
low = (low + 0x40) & 0xffffff80;
if (low == 0)
high += 1;
}
}
low &= 0xffffff80;
#endif
}
ip = (double) high;
ip = REAL_VALUE_LDEXP (ip, 32) + (double) low;
/* Apply shifts and exponent value as power of 2. */
ip = REAL_VALUE_LDEXP (ip, expon - (nrmcount + frexpon));
if (sign < 0)
ip = -ip;
return ip;
}
#endif /* no REAL_ARITHMETIC */
/* Given T, an expression, return the negation of T. Allow for T to be
null, in which case return null. */
static tree
negate_expr (t)
tree t;
{
tree type;
tree tem;
if (t == 0)
return 0;
type = TREE_TYPE (t);
STRIP_SIGN_NOPS (t);
switch (TREE_CODE (t))
{
case INTEGER_CST:
case REAL_CST:
if (! TREE_UNSIGNED (type)
&& 0 != (tem = fold (build1 (NEGATE_EXPR, type, t)))
&& ! TREE_OVERFLOW (tem))
return tem;
break;
case NEGATE_EXPR:
return convert (type, TREE_OPERAND (t, 0));
case MINUS_EXPR:
/* - (A - B) -> B - A */
if (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
return convert (type,
fold (build (MINUS_EXPR, TREE_TYPE (t),
TREE_OPERAND (t, 1),
TREE_OPERAND (t, 0))));
break;
default:
break;
}
return convert (type, fold (build1 (NEGATE_EXPR, TREE_TYPE (t), t)));
}
/* Split a tree IN into a constant, literal and variable parts that could be
combined with CODE to make IN. "constant" means an expression with
TREE_CONSTANT but that isn't an actual constant. CODE must be a
commutative arithmetic operation. Store the constant part into *CONP,
the literal in &LITP and return the variable part. If a part isn't
present, set it to null. If the tree does not decompose in this way,
return the entire tree as the variable part and the other parts as null.
If CODE is PLUS_EXPR we also split trees that use MINUS_EXPR. In that
case, we negate an operand that was subtracted. If NEGATE_P is true, we
are negating all of IN.
If IN is itself a literal or constant, return it as appropriate.
Note that we do not guarantee that any of the three values will be the
same type as IN, but they will have the same signedness and mode. */
static tree
split_tree (in, code, conp, litp, negate_p)
tree in;
enum tree_code code;
tree *conp, *litp;
int negate_p;
{
tree var = 0;
*conp = 0;
*litp = 0;
/* Strip any conversions that don't change the machine mode or signedness. */
STRIP_SIGN_NOPS (in);
if (TREE_CODE (in) == INTEGER_CST || TREE_CODE (in) == REAL_CST)
*litp = in;
else if (TREE_CODE (in) == code
|| (! FLOAT_TYPE_P (TREE_TYPE (in))
/* We can associate addition and subtraction together (even
though the C standard doesn't say so) for integers because
the value is not affected. For reals, the value might be
affected, so we can't. */
&& ((code == PLUS_EXPR && TREE_CODE (in) == MINUS_EXPR)
|| (code == MINUS_EXPR && TREE_CODE (in) == PLUS_EXPR))))
{
tree op0 = TREE_OPERAND (in, 0);
tree op1 = TREE_OPERAND (in, 1);
int neg1_p = TREE_CODE (in) == MINUS_EXPR;
int neg_litp_p = 0, neg_conp_p = 0, neg_var_p = 0;
/* First see if either of the operands is a literal, then a constant. */
if (TREE_CODE (op0) == INTEGER_CST || TREE_CODE (op0) == REAL_CST)
*litp = op0, op0 = 0;
else if (TREE_CODE (op1) == INTEGER_CST || TREE_CODE (op1) == REAL_CST)
*litp = op1, neg_litp_p = neg1_p, op1 = 0;
if (op0 != 0 && TREE_CONSTANT (op0))
*conp = op0, op0 = 0;
else if (op1 != 0 && TREE_CONSTANT (op1))
*conp = op1, neg_conp_p = neg1_p, op1 = 0;
/* If we haven't dealt with either operand, this is not a case we can
decompose. Otherwise, VAR is either of the ones remaining, if any. */
if (op0 != 0 && op1 != 0)
var = in;
else if (op0 != 0)
var = op0;
else
var = op1, neg_var_p = neg1_p;
/* Now do any needed negations. */
if (neg_litp_p) *litp = negate_expr (*litp);
if (neg_conp_p) *conp = negate_expr (*conp);
if (neg_var_p) var = negate_expr (var);
}
else if (TREE_CONSTANT (in))
*conp = in;
else
var = in;
if (negate_p)
{
var = negate_expr (var);
*conp = negate_expr (*conp);
*litp = negate_expr (*litp);
}
return var;
}
/* Re-associate trees split by the above function. T1 and T2 are either
expressions to associate or null. Return the new expression, if any. If
we build an operation, do it in TYPE and with CODE, except if CODE is a
MINUS_EXPR, in which case we use PLUS_EXPR since split_tree will already
have taken care of the negations. */
static tree
associate_trees (t1, t2, code, type)
tree t1, t2;
enum tree_code code;
tree type;
{
if (t1 == 0)
return t2;
else if (t2 == 0)
return t1;
if (code == MINUS_EXPR)
code = PLUS_EXPR;
/* If either input is CODE, a PLUS_EXPR, or a MINUS_EXPR, don't
try to fold this since we will have infinite recursion. But do
deal with any NEGATE_EXPRs. */
if (TREE_CODE (t1) == code || TREE_CODE (t2) == code
|| TREE_CODE (t1) == MINUS_EXPR || TREE_CODE (t2) == MINUS_EXPR)
{
if (TREE_CODE (t1) == NEGATE_EXPR)
return build (MINUS_EXPR, type, convert (type, t2),
convert (type, TREE_OPERAND (t1, 0)));
else if (TREE_CODE (t2) == NEGATE_EXPR)
return build (MINUS_EXPR, type, convert (type, t1),
convert (type, TREE_OPERAND (t2, 0)));
else
return build (code, type, convert (type, t1), convert (type, t2));
}
return fold (build (code, type, convert (type, t1), convert (type, t2)));
}
/* Combine two integer constants ARG1 and ARG2 under operation CODE
to produce a new constant.
If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
static tree
int_const_binop (code, arg1, arg2, notrunc)
enum tree_code code;
tree arg1, arg2;
int notrunc;
{
unsigned HOST_WIDE_INT int1l, int2l;
HOST_WIDE_INT int1h, int2h;
unsigned HOST_WIDE_INT low;
HOST_WIDE_INT hi;
unsigned HOST_WIDE_INT garbagel;
HOST_WIDE_INT garbageh;
tree t;
tree type = TREE_TYPE (arg1);
int uns = TREE_UNSIGNED (type);
int is_sizetype
= (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type));
int overflow = 0;
int no_overflow = 0;
int1l = TREE_INT_CST_LOW (arg1);
int1h = TREE_INT_CST_HIGH (arg1);
int2l = TREE_INT_CST_LOW (arg2);
int2h = TREE_INT_CST_HIGH (arg2);
switch (code)
{
case BIT_IOR_EXPR:
low = int1l | int2l, hi = int1h | int2h;
break;
case BIT_XOR_EXPR:
low = int1l ^ int2l, hi = int1h ^ int2h;
break;
case BIT_AND_EXPR:
low = int1l & int2l, hi = int1h & int2h;
break;
case BIT_ANDTC_EXPR:
low = int1l & ~int2l, hi = int1h & ~int2h;
break;
case RSHIFT_EXPR:
int2l = -int2l;
case LSHIFT_EXPR:
/* It's unclear from the C standard whether shifts can overflow.
The following code ignores overflow; perhaps a C standard
interpretation ruling is needed. */
lshift_double (int1l, int1h, int2l, TYPE_PRECISION (type),
&low, &hi, !uns);
no_overflow = 1;
break;
case RROTATE_EXPR:
int2l = - int2l;
case LROTATE_EXPR:
lrotate_double (int1l, int1h, int2l, TYPE_PRECISION (type),
&low, &hi);
break;
case PLUS_EXPR:
overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
break;
case MINUS_EXPR:
neg_double (int2l, int2h, &low, &hi);
add_double (int1l, int1h, low, hi, &low, &hi);
overflow = OVERFLOW_SUM_SIGN (hi, int2h, int1h);
break;
case MULT_EXPR:
overflow = mul_double (int1l, int1h, int2l, int2h, &low, &hi);
break;
case TRUNC_DIV_EXPR:
case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
case EXACT_DIV_EXPR:
/* This is a shortcut for a common special case. */
if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& ! TREE_CONSTANT_OVERFLOW (arg2)
&& int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
{
if (code == CEIL_DIV_EXPR)
int1l += int2l - 1;
low = int1l / int2l, hi = 0;
break;
}
/* ... fall through ... */
case ROUND_DIV_EXPR:
if (int2h == 0 && int2l == 1)
{
low = int1l, hi = int1h;
break;
}
if (int1l == int2l && int1h == int2h
&& ! (int1l == 0 && int1h == 0))
{
low = 1, hi = 0;
break;
}
overflow = div_and_round_double (code, uns, int1l, int1h, int2l, int2h,
&low, &hi, &garbagel, &garbageh);
break;
case TRUNC_MOD_EXPR:
case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
/* This is a shortcut for a common special case. */
if (int2h == 0 && (HOST_WIDE_INT) int2l > 0
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& ! TREE_CONSTANT_OVERFLOW (arg2)
&& int1h == 0 && (HOST_WIDE_INT) int1l >= 0)
{
if (code == CEIL_MOD_EXPR)
int1l += int2l - 1;
low = int1l % int2l, hi = 0;
break;
}
/* ... fall through ... */
case ROUND_MOD_EXPR:
overflow = div_and_round_double (code, uns,
int1l, int1h, int2l, int2h,
&garbagel, &garbageh, &low, &hi);
break;
case MIN_EXPR:
case MAX_EXPR:
if (uns)
low = (((unsigned HOST_WIDE_INT) int1h
< (unsigned HOST_WIDE_INT) int2h)
|| (((unsigned HOST_WIDE_INT) int1h
== (unsigned HOST_WIDE_INT) int2h)
&& int1l < int2l));
else
low = (int1h < int2h
|| (int1h == int2h && int1l < int2l));
if (low == (code == MIN_EXPR))
low = int1l, hi = int1h;
else
low = int2l, hi = int2h;
break;
default:
abort ();
}
/* If this is for a sizetype, can be represented as one (signed)
HOST_WIDE_INT word, and doesn't overflow, use size_int since it caches
constants. */
if (is_sizetype
&& ((hi == 0 && (HOST_WIDE_INT) low >= 0)
|| (hi == -1 && (HOST_WIDE_INT) low < 0))
&& overflow == 0 && ! TREE_OVERFLOW (arg1) && ! TREE_OVERFLOW (arg2))
return size_int_type_wide (low, type);
else
{
t = build_int_2 (low, hi);
TREE_TYPE (t) = TREE_TYPE (arg1);
}
TREE_OVERFLOW (t)
= ((notrunc
? (!uns || is_sizetype) && overflow
: (force_fit_type (t, (!uns || is_sizetype) && overflow)
&& ! no_overflow))
| TREE_OVERFLOW (arg1)
| TREE_OVERFLOW (arg2));
/* If we're doing a size calculation, unsigned arithmetic does overflow.
So check if force_fit_type truncated the value. */
if (is_sizetype
&& ! TREE_OVERFLOW (t)
&& (TREE_INT_CST_HIGH (t) != hi
|| TREE_INT_CST_LOW (t) != low))
TREE_OVERFLOW (t) = 1;
TREE_CONSTANT_OVERFLOW (t) = (TREE_OVERFLOW (t)
| TREE_CONSTANT_OVERFLOW (arg1)
| TREE_CONSTANT_OVERFLOW (arg2));
return t;
}
/* Define input and output argument for const_binop_1. */
struct cb_args
{
enum tree_code code; /* Input: tree code for operation. */
tree type; /* Input: tree type for operation. */
REAL_VALUE_TYPE d1, d2; /* Input: floating point operands. */
tree t; /* Output: constant for result. */
};
/* Do the real arithmetic for const_binop while protected by a
float overflow handler. */
static void
const_binop_1 (data)
PTR data;
{
struct cb_args *args = (struct cb_args *) data;
REAL_VALUE_TYPE value;
#ifdef REAL_ARITHMETIC
REAL_ARITHMETIC (value, args->code, args->d1, args->d2);
#else
switch (args->code)
{
case PLUS_EXPR:
value = args->d1 + args->d2;
break;
case MINUS_EXPR:
value = args->d1 - args->d2;
break;
case MULT_EXPR:
value = args->d1 * args->d2;
break;
case RDIV_EXPR:
#ifndef REAL_INFINITY
if (args->d2 == 0)
abort ();
#endif
value = args->d1 / args->d2;
break;
case MIN_EXPR:
value = MIN (args->d1, args->d2);
break;
case MAX_EXPR:
value = MAX (args->d1, args->d2);
break;
default:
abort ();
}
#endif /* no REAL_ARITHMETIC */
args->t
= build_real (args->type,
real_value_truncate (TYPE_MODE (args->type), value));
}
/* Combine two constants ARG1 and ARG2 under operation CODE to produce a new
constant. We assume ARG1 and ARG2 have the same data type, or at least
are the same kind of constant and the same machine mode.
If NOTRUNC is nonzero, do not truncate the result to fit the data type. */
static tree
const_binop (code, arg1, arg2, notrunc)
enum tree_code code;
tree arg1, arg2;
int notrunc;
{
STRIP_NOPS (arg1);
STRIP_NOPS (arg2);
if (TREE_CODE (arg1) == INTEGER_CST)
return int_const_binop (code, arg1, arg2, notrunc);
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
if (TREE_CODE (arg1) == REAL_CST)
{
REAL_VALUE_TYPE d1;
REAL_VALUE_TYPE d2;
int overflow = 0;
tree t;
struct cb_args args;
d1 = TREE_REAL_CST (arg1);
d2 = TREE_REAL_CST (arg2);
/* If either operand is a NaN, just return it. Otherwise, set up
for floating-point trap; we return an overflow. */
if (REAL_VALUE_ISNAN (d1))
return arg1;
else if (REAL_VALUE_ISNAN (d2))
return arg2;
/* Setup input for const_binop_1() */
args.type = TREE_TYPE (arg1);
args.d1 = d1;
args.d2 = d2;
args.code = code;
if (do_float_handler (const_binop_1, (PTR) &args))
/* Receive output from const_binop_1. */
t = args.t;
else
{
/* We got an exception from const_binop_1. */
t = copy_node (arg1);
overflow = 1;
}
TREE_OVERFLOW (t)
= (force_fit_type (t, overflow)
| TREE_OVERFLOW (arg1) | TREE_OVERFLOW (arg2));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t)
| TREE_CONSTANT_OVERFLOW (arg1)
| TREE_CONSTANT_OVERFLOW (arg2);
return t;
}
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
if (TREE_CODE (arg1) == COMPLEX_CST)
{
tree type = TREE_TYPE (arg1);
tree r1 = TREE_REALPART (arg1);
tree i1 = TREE_IMAGPART (arg1);
tree r2 = TREE_REALPART (arg2);
tree i2 = TREE_IMAGPART (arg2);
tree t;
switch (code)
{
case PLUS_EXPR:
t = build_complex (type,
const_binop (PLUS_EXPR, r1, r2, notrunc),
const_binop (PLUS_EXPR, i1, i2, notrunc));
break;
case MINUS_EXPR:
t = build_complex (type,
const_binop (MINUS_EXPR, r1, r2, notrunc),
const_binop (MINUS_EXPR, i1, i2, notrunc));
break;
case MULT_EXPR:
t = build_complex (type,
const_binop (MINUS_EXPR,
const_binop (MULT_EXPR,
r1, r2, notrunc),
const_binop (MULT_EXPR,
i1, i2, notrunc),
notrunc),
const_binop (PLUS_EXPR,
const_binop (MULT_EXPR,
r1, i2, notrunc),
const_binop (MULT_EXPR,
i1, r2, notrunc),
notrunc));
break;
case RDIV_EXPR:
{
tree magsquared
= const_binop (PLUS_EXPR,
const_binop (MULT_EXPR, r2, r2, notrunc),
const_binop (MULT_EXPR, i2, i2, notrunc),
notrunc);
t = build_complex (type,
const_binop
(INTEGRAL_TYPE_P (TREE_TYPE (r1))
? TRUNC_DIV_EXPR : RDIV_EXPR,
const_binop (PLUS_EXPR,
const_binop (MULT_EXPR, r1, r2,
notrunc),
const_binop (MULT_EXPR, i1, i2,
notrunc),
notrunc),
magsquared, notrunc),
const_binop
(INTEGRAL_TYPE_P (TREE_TYPE (r1))
? TRUNC_DIV_EXPR : RDIV_EXPR,
const_binop (MINUS_EXPR,
const_binop (MULT_EXPR, i1, r2,
notrunc),
const_binop (MULT_EXPR, r1, i2,
notrunc),
notrunc),
magsquared, notrunc));
}
break;
default:
abort ();
}
return t;
}
return 0;
}
/* These are the hash table functions for the hash table of INTEGER_CST
nodes of a sizetype. */
/* Return the hash code code X, an INTEGER_CST. */
static hashval_t
size_htab_hash (x)
const void *x;
{
tree t = (tree) x;
return (TREE_INT_CST_HIGH (t) ^ TREE_INT_CST_LOW (t)
^ (hashval_t) ((long) TREE_TYPE (t) >> 3)
^ (TREE_OVERFLOW (t) << 20));
}
/* Return non-zero if the value represented by *X (an INTEGER_CST tree node)
is the same as that given by *Y, which is the same. */
static int
size_htab_eq (x, y)
const void *x;
const void *y;
{
tree xt = (tree) x;
tree yt = (tree) y;
return (TREE_INT_CST_HIGH (xt) == TREE_INT_CST_HIGH (yt)
&& TREE_INT_CST_LOW (xt) == TREE_INT_CST_LOW (yt)
&& TREE_TYPE (xt) == TREE_TYPE (yt)
&& TREE_OVERFLOW (xt) == TREE_OVERFLOW (yt));
}
/* Return an INTEGER_CST with value whose low-order HOST_BITS_PER_WIDE_INT
bits are given by NUMBER and of the sizetype represented by KIND. */
tree
size_int_wide (number, kind)
HOST_WIDE_INT number;
enum size_type_kind kind;
{
return size_int_type_wide (number, sizetype_tab[(int) kind]);
}
/* Likewise, but the desired type is specified explicitly. */
tree
size_int_type_wide (number, type)
HOST_WIDE_INT number;
tree type;
{
static htab_t size_htab = 0;
static tree new_const = 0;
PTR *slot;
if (size_htab == 0)
{
size_htab = htab_create (1024, size_htab_hash, size_htab_eq, NULL);
ggc_add_deletable_htab (size_htab, NULL, NULL);
new_const = make_node (INTEGER_CST);
ggc_add_tree_root (&new_const, 1);
}
/* Adjust NEW_CONST to be the constant we want. If it's already in the
hash table, we return the value from the hash table. Otherwise, we
place that in the hash table and make a new node for the next time. */
TREE_INT_CST_LOW (new_const) = number;
TREE_INT_CST_HIGH (new_const) = number < 0 ? -1 : 0;
TREE_TYPE (new_const) = type;
TREE_OVERFLOW (new_const) = TREE_CONSTANT_OVERFLOW (new_const)
= force_fit_type (new_const, 0);
slot = htab_find_slot (size_htab, new_const, INSERT);
if (*slot == 0)
{
tree t = new_const;
*slot = (PTR) new_const;
new_const = make_node (INTEGER_CST);
return t;
}
else
return (tree) *slot;
}
/* Combine operands OP1 and OP2 with arithmetic operation CODE. CODE
is a tree code. The type of the result is taken from the operands.
Both must be the same type integer type and it must be a size type.
If the operands are constant, so is the result. */
tree
size_binop (code, arg0, arg1)
enum tree_code code;
tree arg0, arg1;
{
tree type = TREE_TYPE (arg0);
if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
|| type != TREE_TYPE (arg1))
abort ();
/* Handle the special case of two integer constants faster. */
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
{
/* And some specific cases even faster than that. */
if (code == PLUS_EXPR && integer_zerop (arg0))
return arg1;
else if ((code == MINUS_EXPR || code == PLUS_EXPR)
&& integer_zerop (arg1))
return arg0;
else if (code == MULT_EXPR && integer_onep (arg0))
return arg1;
/* Handle general case of two integer constants. */
return int_const_binop (code, arg0, arg1, 0);
}
if (arg0 == error_mark_node || arg1 == error_mark_node)
return error_mark_node;
return fold (build (code, type, arg0, arg1));
}
/* Given two values, either both of sizetype or both of bitsizetype,
compute the difference between the two values. Return the value
in signed type corresponding to the type of the operands. */
tree
size_diffop (arg0, arg1)
tree arg0, arg1;
{
tree type = TREE_TYPE (arg0);
tree ctype;
if (TREE_CODE (type) != INTEGER_TYPE || ! TYPE_IS_SIZETYPE (type)
|| type != TREE_TYPE (arg1))
abort ();
/* If the type is already signed, just do the simple thing. */
if (! TREE_UNSIGNED (type))
return size_binop (MINUS_EXPR, arg0, arg1);
ctype = (type == bitsizetype || type == ubitsizetype
? sbitsizetype : ssizetype);
/* If either operand is not a constant, do the conversions to the signed
type and subtract. The hardware will do the right thing with any
overflow in the subtraction. */
if (TREE_CODE (arg0) != INTEGER_CST || TREE_CODE (arg1) != INTEGER_CST)
return size_binop (MINUS_EXPR, convert (ctype, arg0),
convert (ctype, arg1));
/* If ARG0 is larger than ARG1, subtract and return the result in CTYPE.
Otherwise, subtract the other way, convert to CTYPE (we know that can't
overflow) and negate (which can't either). Special-case a result
of zero while we're here. */
if (tree_int_cst_equal (arg0, arg1))
return convert (ctype, integer_zero_node);
else if (tree_int_cst_lt (arg1, arg0))
return convert (ctype, size_binop (MINUS_EXPR, arg0, arg1));
else
return size_binop (MINUS_EXPR, convert (ctype, integer_zero_node),
convert (ctype, size_binop (MINUS_EXPR, arg1, arg0)));
}
/* This structure is used to communicate arguments to fold_convert_1. */
struct fc_args
{
tree arg1; /* Input: value to convert. */
tree type; /* Input: type to convert value to. */
tree t; /* Output: result of conversion. */
};
/* Function to convert floating-point constants, protected by floating
point exception handler. */
static void
fold_convert_1 (data)
PTR data;
{
struct fc_args *args = (struct fc_args *) data;
args->t = build_real (args->type,
real_value_truncate (TYPE_MODE (args->type),
TREE_REAL_CST (args->arg1)));
}
/* Given T, a tree representing type conversion of ARG1, a constant,
return a constant tree representing the result of conversion. */
static tree
fold_convert (t, arg1)
tree t;
tree arg1;
{
tree type = TREE_TYPE (t);
int overflow = 0;
if (POINTER_TYPE_P (type) || INTEGRAL_TYPE_P (type))
{
if (TREE_CODE (arg1) == INTEGER_CST)
{
/* If we would build a constant wider than GCC supports,
leave the conversion unfolded. */
if (TYPE_PRECISION (type) > 2 * HOST_BITS_PER_WIDE_INT)
return t;
/* If we are trying to make a sizetype for a small integer, use
size_int to pick up cached types to reduce duplicate nodes. */
if (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)
&& !TREE_CONSTANT_OVERFLOW (arg1)
&& compare_tree_int (arg1, 10000) < 0)
return size_int_type_wide (TREE_INT_CST_LOW (arg1), type);
/* Given an integer constant, make new constant with new type,
appropriately sign-extended or truncated. */
t = build_int_2 (TREE_INT_CST_LOW (arg1),
TREE_INT_CST_HIGH (arg1));
TREE_TYPE (t) = type;
/* Indicate an overflow if (1) ARG1 already overflowed,
or (2) force_fit_type indicates an overflow.
Tell force_fit_type that an overflow has already occurred
if ARG1 is a too-large unsigned value and T is signed.
But don't indicate an overflow if converting a pointer. */
TREE_OVERFLOW (t)
= ((force_fit_type (t,
(TREE_INT_CST_HIGH (arg1) < 0
&& (TREE_UNSIGNED (type)
< TREE_UNSIGNED (TREE_TYPE (arg1)))))
&& ! POINTER_TYPE_P (TREE_TYPE (arg1)))
|| TREE_OVERFLOW (arg1));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
}
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
else if (TREE_CODE (arg1) == REAL_CST)
{
/* Don't initialize these, use assignments.
Initialized local aggregates don't work on old compilers. */
REAL_VALUE_TYPE x;
REAL_VALUE_TYPE l;
REAL_VALUE_TYPE u;
tree type1 = TREE_TYPE (arg1);
int no_upper_bound;
x = TREE_REAL_CST (arg1);
l = real_value_from_int_cst (type1, TYPE_MIN_VALUE (type));
no_upper_bound = (TYPE_MAX_VALUE (type) == NULL);
if (!no_upper_bound)
u = real_value_from_int_cst (type1, TYPE_MAX_VALUE (type));
/* See if X will be in range after truncation towards 0.
To compensate for truncation, move the bounds away from 0,
but reject if X exactly equals the adjusted bounds. */
#ifdef REAL_ARITHMETIC
REAL_ARITHMETIC (l, MINUS_EXPR, l, dconst1);
if (!no_upper_bound)
REAL_ARITHMETIC (u, PLUS_EXPR, u, dconst1);
#else
l--;
if (!no_upper_bound)
u++;
#endif
/* If X is a NaN, use zero instead and show we have an overflow.
Otherwise, range check. */
if (REAL_VALUE_ISNAN (x))
overflow = 1, x = dconst0;
else if (! (REAL_VALUES_LESS (l, x)
&& !no_upper_bound
&& REAL_VALUES_LESS (x, u)))
overflow = 1;
#ifndef REAL_ARITHMETIC
{
HOST_WIDE_INT low, high;
HOST_WIDE_INT half_word
= (HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2);
if (x < 0)
x = -x;
high = (HOST_WIDE_INT) (x / half_word / half_word);
x -= (REAL_VALUE_TYPE) high * half_word * half_word;
if (x >= (REAL_VALUE_TYPE) half_word * half_word / 2)
{
low = x - (REAL_VALUE_TYPE) half_word * half_word / 2;
low |= (HOST_WIDE_INT) -1 << (HOST_BITS_PER_WIDE_INT - 1);
}
else
low = (HOST_WIDE_INT) x;
if (TREE_REAL_CST (arg1) < 0)
neg_double (low, high, &low, &high);
t = build_int_2 (low, high);
}
#else
{
HOST_WIDE_INT low, high;
REAL_VALUE_TO_INT (&low, &high, x);
t = build_int_2 (low, high);
}
#endif
TREE_TYPE (t) = type;
TREE_OVERFLOW (t)
= TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
}
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
TREE_TYPE (t) = type;
}
else if (TREE_CODE (type) == REAL_TYPE)
{
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
if (TREE_CODE (arg1) == INTEGER_CST)
return build_real_from_int_cst (type, arg1);
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
if (TREE_CODE (arg1) == REAL_CST)
{
struct fc_args args;
if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
{
t = arg1;
TREE_TYPE (arg1) = type;
return t;
}
/* Setup input for fold_convert_1() */
args.arg1 = arg1;
args.type = type;
if (do_float_handler (fold_convert_1, (PTR) &args))
{
/* Receive output from fold_convert_1() */
t = args.t;
}
else
{
/* We got an exception from fold_convert_1() */
overflow = 1;
t = copy_node (arg1);
}
TREE_OVERFLOW (t)
= TREE_OVERFLOW (arg1) | force_fit_type (t, overflow);
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg1);
return t;
}
}
TREE_CONSTANT (t) = 1;
return t;
}
/* Return an expr equal to X but certainly not valid as an lvalue. */
tree
non_lvalue (x)
tree x;
{
tree result;
/* These things are certainly not lvalues. */
if (TREE_CODE (x) == NON_LVALUE_EXPR
|| TREE_CODE (x) == INTEGER_CST
|| TREE_CODE (x) == REAL_CST
|| TREE_CODE (x) == STRING_CST
|| TREE_CODE (x) == ADDR_EXPR)
return x;
result = build1 (NON_LVALUE_EXPR, TREE_TYPE (x), x);
TREE_CONSTANT (result) = TREE_CONSTANT (x);
return result;
}
/* Nonzero means lvalues are limited to those valid in pedantic ANSI C.
Zero means allow extended lvalues. */
int pedantic_lvalues;
/* When pedantic, return an expr equal to X but certainly not valid as a
pedantic lvalue. Otherwise, return X. */
tree
pedantic_non_lvalue (x)
tree x;
{
if (pedantic_lvalues)
return non_lvalue (x);
else
return x;
}
/* Given a tree comparison code, return the code that is the logical inverse
of the given code. It is not safe to do this for floating-point
comparisons, except for NE_EXPR and EQ_EXPR. */
static enum tree_code
invert_tree_comparison (code)
enum tree_code code;
{
switch (code)
{
case EQ_EXPR:
return NE_EXPR;
case NE_EXPR:
return EQ_EXPR;
case GT_EXPR:
return LE_EXPR;
case GE_EXPR:
return LT_EXPR;
case LT_EXPR:
return GE_EXPR;
case LE_EXPR:
return GT_EXPR;
default:
abort ();
}
}
/* Similar, but return the comparison that results if the operands are
swapped. This is safe for floating-point. */
static enum tree_code
swap_tree_comparison (code)
enum tree_code code;
{
switch (code)
{
case EQ_EXPR:
case NE_EXPR:
return code;
case GT_EXPR:
return LT_EXPR;
case GE_EXPR:
return LE_EXPR;
case LT_EXPR:
return GT_EXPR;
case LE_EXPR:
return GE_EXPR;
default:
abort ();
}
}
/* Return nonzero if CODE is a tree code that represents a truth value. */
static int
truth_value_p (code)
enum tree_code code;
{
return (TREE_CODE_CLASS (code) == '<'
|| code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
|| code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
|| code == TRUTH_XOR_EXPR || code == TRUTH_NOT_EXPR);
}
/* Return nonzero if two operands are necessarily equal.
If ONLY_CONST is non-zero, only return non-zero for constants.
This function tests whether the operands are indistinguishable;
it does not test whether they are equal using C's == operation.
The distinction is important for IEEE floating point, because
(1) -0.0 and 0.0 are distinguishable, but -0.0==0.0, and
(2) two NaNs may be indistinguishable, but NaN!=NaN. */
int
operand_equal_p (arg0, arg1, only_const)
tree arg0, arg1;
int only_const;
{
/* If both types don't have the same signedness, then we can't consider
them equal. We must check this before the STRIP_NOPS calls
because they may change the signedness of the arguments. */
if (TREE_UNSIGNED (TREE_TYPE (arg0)) != TREE_UNSIGNED (TREE_TYPE (arg1)))
return 0;
STRIP_NOPS (arg0);
STRIP_NOPS (arg1);
if (TREE_CODE (arg0) != TREE_CODE (arg1)
/* This is needed for conversions and for COMPONENT_REF.
Might as well play it safe and always test this. */
|| TREE_CODE (TREE_TYPE (arg0)) == ERROR_MARK
|| TREE_CODE (TREE_TYPE (arg1)) == ERROR_MARK
|| TYPE_MODE (TREE_TYPE (arg0)) != TYPE_MODE (TREE_TYPE (arg1)))
return 0;
/* If ARG0 and ARG1 are the same SAVE_EXPR, they are necessarily equal.
We don't care about side effects in that case because the SAVE_EXPR
takes care of that for us. In all other cases, two expressions are
equal if they have no side effects. If we have two identical
expressions with side effects that should be treated the same due
to the only side effects being identical SAVE_EXPR's, that will
be detected in the recursive calls below. */
if (arg0 == arg1 && ! only_const
&& (TREE_CODE (arg0) == SAVE_EXPR
|| (! TREE_SIDE_EFFECTS (arg0) && ! TREE_SIDE_EFFECTS (arg1))))
return 1;
/* Next handle constant cases, those for which we can return 1 even
if ONLY_CONST is set. */
if (TREE_CONSTANT (arg0) && TREE_CONSTANT (arg1))
switch (TREE_CODE (arg0))
{
case INTEGER_CST:
return (! TREE_CONSTANT_OVERFLOW (arg0)
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& tree_int_cst_equal (arg0, arg1));
case REAL_CST:
return (! TREE_CONSTANT_OVERFLOW (arg0)
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& REAL_VALUES_IDENTICAL (TREE_REAL_CST (arg0),
TREE_REAL_CST (arg1)));
case COMPLEX_CST:
return (operand_equal_p (TREE_REALPART (arg0), TREE_REALPART (arg1),
only_const)
&& operand_equal_p (TREE_IMAGPART (arg0), TREE_IMAGPART (arg1),
only_const));
case STRING_CST:
return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1)
&& ! memcmp (TREE_STRING_POINTER (arg0),
TREE_STRING_POINTER (arg1),
TREE_STRING_LENGTH (arg0)));
case ADDR_EXPR:
return operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0),
0);
default:
break;
}
if (only_const)
return 0;
switch (TREE_CODE_CLASS (TREE_CODE (arg0)))
{
case '1':
/* Two conversions are equal only if signedness and modes match. */
if ((TREE_CODE (arg0) == NOP_EXPR || TREE_CODE (arg0) == CONVERT_EXPR)
&& (TREE_UNSIGNED (TREE_TYPE (arg0))
!= TREE_UNSIGNED (TREE_TYPE (arg1))))
return 0;
return operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0), 0);
case '<':
case '2':
if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1),
0))
return 1;
/* For commutative ops, allow the other order. */
return ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MULT_EXPR
|| TREE_CODE (arg0) == MIN_EXPR || TREE_CODE (arg0) == MAX_EXPR
|| TREE_CODE (arg0) == BIT_IOR_EXPR
|| TREE_CODE (arg0) == BIT_XOR_EXPR
|| TREE_CODE (arg0) == BIT_AND_EXPR
|| TREE_CODE (arg0) == NE_EXPR || TREE_CODE (arg0) == EQ_EXPR)
&& operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 1), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 0), 0));
case 'r':
/* If either of the pointer (or reference) expressions we are dereferencing
contain a side effect, these cannot be equal. */
if (TREE_SIDE_EFFECTS (arg0)
|| TREE_SIDE_EFFECTS (arg1))
return 0;
switch (TREE_CODE (arg0))
{
case INDIRECT_REF:
return operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0), 0);
case COMPONENT_REF:
case ARRAY_REF:
case ARRAY_RANGE_REF:
return (operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0));
case BIT_FIELD_REF:
return (operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0)
&& operand_equal_p (TREE_OPERAND (arg0, 2),
TREE_OPERAND (arg1, 2), 0));
default:
return 0;
}
case 'e':
if (TREE_CODE (arg0) == RTL_EXPR)
return rtx_equal_p (RTL_EXPR_RTL (arg0), RTL_EXPR_RTL (arg1));
return 0;
default:
return 0;
}
}
/* Similar to operand_equal_p, but see if ARG0 might have been made by
shorten_compare from ARG1 when ARG1 was being compared with OTHER.
When in doubt, return 0. */
static int
operand_equal_for_comparison_p (arg0, arg1, other)
tree arg0, arg1;
tree other;
{
int unsignedp1, unsignedpo;
tree primarg0, primarg1, primother;
unsigned int correct_width;
if (operand_equal_p (arg0, arg1, 0))
return 1;
if (! INTEGRAL_TYPE_P (TREE_TYPE (arg0))
|| ! INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
return 0;
/* Discard any conversions that don't change the modes of ARG0 and ARG1
and see if the inner values are the same. This removes any
signedness comparison, which doesn't matter here. */
primarg0 = arg0, primarg1 = arg1;
STRIP_NOPS (primarg0);
STRIP_NOPS (primarg1);
if (operand_equal_p (primarg0, primarg1, 0))
return 1;
/* Duplicate what shorten_compare does to ARG1 and see if that gives the
actual comparison operand, ARG0.
First throw away any conversions to wider types
already present in the operands. */
primarg1 = get_narrower (arg1, &unsignedp1);
primother = get_narrower (other, &unsignedpo);
correct_width = TYPE_PRECISION (TREE_TYPE (arg1));
if (unsignedp1 == unsignedpo
&& TYPE_PRECISION (TREE_TYPE (primarg1)) < correct_width
&& TYPE_PRECISION (TREE_TYPE (primother)) < correct_width)
{
tree type = TREE_TYPE (arg0);
/* Make sure shorter operand is extended the right way
to match the longer operand. */
primarg1 = convert (signed_or_unsigned_type (unsignedp1,
TREE_TYPE (primarg1)),
primarg1);
if (operand_equal_p (arg0, convert (type, primarg1), 0))
return 1;
}
return 0;
}
/* See if ARG is an expression that is either a comparison or is performing
arithmetic on comparisons. The comparisons must only be comparing
two different values, which will be stored in *CVAL1 and *CVAL2; if
they are non-zero it means that some operands have already been found.
No variables may be used anywhere else in the expression except in the
comparisons. If SAVE_P is true it means we removed a SAVE_EXPR around
the expression and save_expr needs to be called with CVAL1 and CVAL2.
If this is true, return 1. Otherwise, return zero. */
static int
twoval_comparison_p (arg, cval1, cval2, save_p)
tree arg;
tree *cval1, *cval2;
int *save_p;
{
enum tree_code code = TREE_CODE (arg);
char class = TREE_CODE_CLASS (code);
/* We can handle some of the 'e' cases here. */
if (class == 'e' && code == TRUTH_NOT_EXPR)
class = '1';
else if (class == 'e'
&& (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR
|| code == COMPOUND_EXPR))
class = '2';
else if (class == 'e' && code == SAVE_EXPR && SAVE_EXPR_RTL (arg) == 0
&& ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg, 0)))
{
/* If we've already found a CVAL1 or CVAL2, this expression is
two complex to handle. */
if (*cval1 || *cval2)
return 0;
class = '1';
*save_p = 1;
}
switch (class)
{
case '1':
return twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p);
case '2':
return (twoval_comparison_p (TREE_OPERAND (arg, 0), cval1, cval2, save_p)
&& twoval_comparison_p (TREE_OPERAND (arg, 1),
cval1, cval2, save_p));
case 'c':
return 1;
case 'e':
if (code == COND_EXPR)
return (twoval_comparison_p (TREE_OPERAND (arg, 0),
cval1, cval2, save_p)
&& twoval_comparison_p (TREE_OPERAND (arg, 1),
cval1, cval2, save_p)
&& twoval_comparison_p (TREE_OPERAND (arg, 2),
cval1, cval2, save_p));
return 0;
case '<':
/* First see if we can handle the first operand, then the second. For
the second operand, we know *CVAL1 can't be zero. It must be that
one side of the comparison is each of the values; test for the
case where this isn't true by failing if the two operands
are the same. */
if (operand_equal_p (TREE_OPERAND (arg, 0),
TREE_OPERAND (arg, 1), 0))
return 0;
if (*cval1 == 0)
*cval1 = TREE_OPERAND (arg, 0);
else if (operand_equal_p (*cval1, TREE_OPERAND (arg, 0), 0))
;
else if (*cval2 == 0)
*cval2 = TREE_OPERAND (arg, 0);
else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 0), 0))
;
else
return 0;
if (operand_equal_p (*cval1, TREE_OPERAND (arg, 1), 0))
;
else if (*cval2 == 0)
*cval2 = TREE_OPERAND (arg, 1);
else if (operand_equal_p (*cval2, TREE_OPERAND (arg, 1), 0))
;
else
return 0;
return 1;
default:
return 0;
}
}
/* ARG is a tree that is known to contain just arithmetic operations and
comparisons. Evaluate the operations in the tree substituting NEW0 for
any occurrence of OLD0 as an operand of a comparison and likewise for
NEW1 and OLD1. */
static tree
eval_subst (arg, old0, new0, old1, new1)
tree arg;
tree old0, new0, old1, new1;
{
tree type = TREE_TYPE (arg);
enum tree_code code = TREE_CODE (arg);
char class = TREE_CODE_CLASS (code);
/* We can handle some of the 'e' cases here. */
if (class == 'e' && code == TRUTH_NOT_EXPR)
class = '1';
else if (class == 'e'
&& (code == TRUTH_ANDIF_EXPR || code == TRUTH_ORIF_EXPR))
class = '2';
switch (class)
{
case '1':
return fold (build1 (code, type,
eval_subst (TREE_OPERAND (arg, 0),
old0, new0, old1, new1)));
case '2':
return fold (build (code, type,
eval_subst (TREE_OPERAND (arg, 0),
old0, new0, old1, new1),
eval_subst (TREE_OPERAND (arg, 1),
old0, new0, old1, new1)));
case 'e':
switch (code)
{
case SAVE_EXPR:
return eval_subst (TREE_OPERAND (arg, 0), old0, new0, old1, new1);
case COMPOUND_EXPR:
return eval_subst (TREE_OPERAND (arg, 1), old0, new0, old1, new1);
case COND_EXPR:
return fold (build (code, type,
eval_subst (TREE_OPERAND (arg, 0),
old0, new0, old1, new1),
eval_subst (TREE_OPERAND (arg, 1),
old0, new0, old1, new1),
eval_subst (TREE_OPERAND (arg, 2),
old0, new0, old1, new1)));
default:
break;
}
/* fall through - ??? */
case '<':
{
tree arg0 = TREE_OPERAND (arg, 0);
tree arg1 = TREE_OPERAND (arg, 1);
/* We need to check both for exact equality and tree equality. The
former will be true if the operand has a side-effect. In that
case, we know the operand occurred exactly once. */
if (arg0 == old0 || operand_equal_p (arg0, old0, 0))
arg0 = new0;
else if (arg0 == old1 || operand_equal_p (arg0, old1, 0))
arg0 = new1;
if (arg1 == old0 || operand_equal_p (arg1, old0, 0))
arg1 = new0;
else if (arg1 == old1 || operand_equal_p (arg1, old1, 0))
arg1 = new1;
return fold (build (code, type, arg0, arg1));
}
default:
return arg;
}
}
/* Return a tree for the case when the result of an expression is RESULT
converted to TYPE and OMITTED was previously an operand of the expression
but is now not needed (e.g., we folded OMITTED * 0).
If OMITTED has side effects, we must evaluate it. Otherwise, just do
the conversion of RESULT to TYPE. */
static tree
omit_one_operand (type, result, omitted)
tree type, result, omitted;
{
tree t = convert (type, result);
if (TREE_SIDE_EFFECTS (omitted))
return build (COMPOUND_EXPR, type, omitted, t);
return non_lvalue (t);
}
/* Similar, but call pedantic_non_lvalue instead of non_lvalue. */
static tree
pedantic_omit_one_operand (type, result, omitted)
tree type, result, omitted;
{
tree t = convert (type, result);
if (TREE_SIDE_EFFECTS (omitted))
return build (COMPOUND_EXPR, type, omitted, t);
return pedantic_non_lvalue (t);
}
/* Return a simplified tree node for the truth-negation of ARG. This
never alters ARG itself. We assume that ARG is an operation that
returns a truth value (0 or 1). */
tree
invert_truthvalue (arg)
tree arg;
{
tree type = TREE_TYPE (arg);
enum tree_code code = TREE_CODE (arg);
if (code == ERROR_MARK)
return arg;
/* If this is a comparison, we can simply invert it, except for
floating-point non-equality comparisons, in which case we just
enclose a TRUTH_NOT_EXPR around what we have. */
if (TREE_CODE_CLASS (code) == '<')
{
if (FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg, 0)))
&& !flag_unsafe_math_optimizations
&& code != NE_EXPR
&& code != EQ_EXPR)
return build1 (TRUTH_NOT_EXPR, type, arg);
else
return build (invert_tree_comparison (code), type,
TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
}
switch (code)
{
case INTEGER_CST:
return convert (type, build_int_2 (integer_zerop (arg), 0));
case TRUTH_AND_EXPR:
return build (TRUTH_OR_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
invert_truthvalue (TREE_OPERAND (arg, 1)));
case TRUTH_OR_EXPR:
return build (TRUTH_AND_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
invert_truthvalue (TREE_OPERAND (arg, 1)));
case TRUTH_XOR_EXPR:
/* Here we can invert either operand. We invert the first operand
unless the second operand is a TRUTH_NOT_EXPR in which case our
result is the XOR of the first operand with the inside of the
negation of the second operand. */
if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
return build (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
else
return build (TRUTH_XOR_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
TREE_OPERAND (arg, 1));
case TRUTH_ANDIF_EXPR:
return build (TRUTH_ORIF_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
invert_truthvalue (TREE_OPERAND (arg, 1)));
case TRUTH_ORIF_EXPR:
return build (TRUTH_ANDIF_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
invert_truthvalue (TREE_OPERAND (arg, 1)));
case TRUTH_NOT_EXPR:
return TREE_OPERAND (arg, 0);
case COND_EXPR:
return build (COND_EXPR, type, TREE_OPERAND (arg, 0),
invert_truthvalue (TREE_OPERAND (arg, 1)),
invert_truthvalue (TREE_OPERAND (arg, 2)));
case COMPOUND_EXPR:
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
invert_truthvalue (TREE_OPERAND (arg, 1)));
case WITH_RECORD_EXPR:
return build (WITH_RECORD_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)),
TREE_OPERAND (arg, 1));
case NON_LVALUE_EXPR:
return invert_truthvalue (TREE_OPERAND (arg, 0));
case NOP_EXPR:
case CONVERT_EXPR:
case FLOAT_EXPR:
return build1 (TREE_CODE (arg), type,
invert_truthvalue (TREE_OPERAND (arg, 0)));
case BIT_AND_EXPR:
if (!integer_onep (TREE_OPERAND (arg, 1)))
break;
return build (EQ_EXPR, type, arg, convert (type, integer_zero_node));
case SAVE_EXPR:
return build1 (TRUTH_NOT_EXPR, type, arg);
case CLEANUP_POINT_EXPR:
return build1 (CLEANUP_POINT_EXPR, type,
invert_truthvalue (TREE_OPERAND (arg, 0)));
default:
break;
}
if (TREE_CODE (TREE_TYPE (arg)) != BOOLEAN_TYPE)
abort ();
return build1 (TRUTH_NOT_EXPR, type, arg);
}
/* Given a bit-wise operation CODE applied to ARG0 and ARG1, see if both
operands are another bit-wise operation with a common input. If so,
distribute the bit operations to save an operation and possibly two if
constants are involved. For example, convert
(A | B) & (A | C) into A | (B & C)
Further simplification will occur if B and C are constants.
If this optimization cannot be done, 0 will be returned. */
static tree
distribute_bit_expr (code, type, arg0, arg1)
enum tree_code code;
tree type;
tree arg0, arg1;
{
tree common;
tree left, right;
if (TREE_CODE (arg0) != TREE_CODE (arg1)
|| TREE_CODE (arg0) == code
|| (TREE_CODE (arg0) != BIT_AND_EXPR
&& TREE_CODE (arg0) != BIT_IOR_EXPR))
return 0;
if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 0), 0))
{
common = TREE_OPERAND (arg0, 0);
left = TREE_OPERAND (arg0, 1);
right = TREE_OPERAND (arg1, 1);
}
else if (operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1, 1), 0))
{
common = TREE_OPERAND (arg0, 0);
left = TREE_OPERAND (arg0, 1);
right = TREE_OPERAND (arg1, 0);
}
else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 0), 0))
{
common = TREE_OPERAND (arg0, 1);
left = TREE_OPERAND (arg0, 0);
right = TREE_OPERAND (arg1, 1);
}
else if (operand_equal_p (TREE_OPERAND (arg0, 1), TREE_OPERAND (arg1, 1), 0))
{
common = TREE_OPERAND (arg0, 1);
left = TREE_OPERAND (arg0, 0);
right = TREE_OPERAND (arg1, 0);
}
else
return 0;
return fold (build (TREE_CODE (arg0), type, common,
fold (build (code, type, left, right))));
}
/* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER
starting at BITPOS. The field is unsigned if UNSIGNEDP is non-zero. */
static tree
make_bit_field_ref (inner, type, bitsize, bitpos, unsignedp)
tree inner;
tree type;
int bitsize, bitpos;
int unsignedp;
{
tree result = build (BIT_FIELD_REF, type, inner,
size_int (bitsize), bitsize_int (bitpos));
TREE_UNSIGNED (result) = unsignedp;
return result;
}
/* Optimize a bit-field compare.
There are two cases: First is a compare against a constant and the
second is a comparison of two items where the fields are at the same
bit position relative to the start of a chunk (byte, halfword, word)
large enough to contain it. In these cases we can avoid the shift
implicit in bitfield extractions.
For constants, we emit a compare of the shifted constant with the
BIT_AND_EXPR of a mask and a byte, halfword, or word of the operand being
compared. For two fields at the same position, we do the ANDs with the
similar mask and compare the result of the ANDs.
CODE is the comparison code, known to be either NE_EXPR or EQ_EXPR.
COMPARE_TYPE is the type of the comparison, and LHS and RHS
are the left and right operands of the comparison, respectively.
If the optimization described above can be done, we return the resulting
tree. Otherwise we return zero. */
static tree
optimize_bit_field_compare (code, compare_type, lhs, rhs)
enum tree_code code;
tree compare_type;
tree lhs, rhs;
{
HOST_WIDE_INT lbitpos, lbitsize, rbitpos, rbitsize, nbitpos, nbitsize;
tree type = TREE_TYPE (lhs);
tree signed_type, unsigned_type;
int const_p = TREE_CODE (rhs) == INTEGER_CST;
enum machine_mode lmode, rmode, nmode;
int lunsignedp, runsignedp;
int lvolatilep = 0, rvolatilep = 0;
tree linner, rinner = NULL_TREE;
tree mask;
tree offset;
/* Get all the information about the extractions being done. If the bit size
if the same as the size of the underlying object, we aren't doing an
extraction at all and so can do nothing. We also don't want to
do anything if the inner expression is a PLACEHOLDER_EXPR since we
then will no longer be able to replace it. */
linner = get_inner_reference (lhs, &lbitsize, &lbitpos, &offset, &lmode,
&lunsignedp, &lvolatilep);
if (linner == lhs || lbitsize == GET_MODE_BITSIZE (lmode) || lbitsize < 0
|| offset != 0 || TREE_CODE (linner) == PLACEHOLDER_EXPR)
return 0;
if (!const_p)
{
/* If this is not a constant, we can only do something if bit positions,
sizes, and signedness are the same. */
rinner = get_inner_reference (rhs, &rbitsize, &rbitpos, &offset, &rmode,
&runsignedp, &rvolatilep);
if (rinner == rhs || lbitpos != rbitpos || lbitsize != rbitsize
|| lunsignedp != runsignedp || offset != 0
|| TREE_CODE (rinner) == PLACEHOLDER_EXPR)
return 0;
}
/* See if we can find a mode to refer to this field. We should be able to,
but fail if we can't. */
nmode = get_best_mode (lbitsize, lbitpos,
const_p ? TYPE_ALIGN (TREE_TYPE (linner))
: MIN (TYPE_ALIGN (TREE_TYPE (linner)),
TYPE_ALIGN (TREE_TYPE (rinner))),
word_mode, lvolatilep || rvolatilep);
if (nmode == VOIDmode)
return 0;
/* Set signed and unsigned types of the precision of this mode for the
shifts below. */
signed_type = type_for_mode (nmode, 0);
unsigned_type = type_for_mode (nmode, 1);
/* Compute the bit position and size for the new reference and our offset
within it. If the new reference is the same size as the original, we
won't optimize anything, so return zero. */
nbitsize = GET_MODE_BITSIZE (nmode);
nbitpos = lbitpos & ~ (nbitsize - 1);
lbitpos -= nbitpos;
if (nbitsize == lbitsize)
return 0;
if (BYTES_BIG_ENDIAN)
lbitpos = nbitsize - lbitsize - lbitpos;
/* Make the mask to be used against the extracted field. */
mask = build_int_2 (~0, ~0);
TREE_TYPE (mask) = unsigned_type;
force_fit_type (mask, 0);
mask = convert (unsigned_type, mask);
mask = const_binop (LSHIFT_EXPR, mask, size_int (nbitsize - lbitsize), 0);
mask = const_binop (RSHIFT_EXPR, mask,
size_int (nbitsize - lbitsize - lbitpos), 0);
if (! const_p)
/* If not comparing with constant, just rework the comparison
and return. */
return build (code, compare_type,
build (BIT_AND_EXPR, unsigned_type,
make_bit_field_ref (linner, unsigned_type,
nbitsize, nbitpos, 1),
mask),
build (BIT_AND_EXPR, unsigned_type,
make_bit_field_ref (rinner, unsigned_type,
nbitsize, nbitpos, 1),
mask));
/* Otherwise, we are handling the constant case. See if the constant is too
big for the field. Warn and return a tree of for 0 (false) if so. We do
this not only for its own sake, but to avoid having to test for this
error case below. If we didn't, we might generate wrong code.
For unsigned fields, the constant shifted right by the field length should
be all zero. For signed fields, the high-order bits should agree with
the sign bit. */
if (lunsignedp)
{
if (! integer_zerop (const_binop (RSHIFT_EXPR,
convert (unsigned_type, rhs),
size_int (lbitsize), 0)))
{
warning ("comparison is always %d due to width of bit-field",
code == NE_EXPR);
return convert (compare_type,
(code == NE_EXPR
? integer_one_node : integer_zero_node));
}
}
else
{
tree tem = const_binop (RSHIFT_EXPR, convert (signed_type, rhs),
size_int (lbitsize - 1), 0);
if (! integer_zerop (tem) && ! integer_all_onesp (tem))
{
warning ("comparison is always %d due to width of bit-field",
code == NE_EXPR);
return convert (compare_type,
(code == NE_EXPR
? integer_one_node : integer_zero_node));
}
}
/* Single-bit compares should always be against zero. */
if (lbitsize == 1 && ! integer_zerop (rhs))
{
code = code == EQ_EXPR ? NE_EXPR : EQ_EXPR;
rhs = convert (type, integer_zero_node);
}
/* Make a new bitfield reference, shift the constant over the
appropriate number of bits and mask it with the computed mask
(in case this was a signed field). If we changed it, make a new one. */
lhs = make_bit_field_ref (linner, unsigned_type, nbitsize, nbitpos, 1);
if (lvolatilep)
{
TREE_SIDE_EFFECTS (lhs) = 1;
TREE_THIS_VOLATILE (lhs) = 1;
}
rhs = fold (const_binop (BIT_AND_EXPR,
const_binop (LSHIFT_EXPR,
convert (unsigned_type, rhs),
size_int (lbitpos), 0),
mask, 0));
return build (code, compare_type,
build (BIT_AND_EXPR, unsigned_type, lhs, mask),
rhs);
}
/* Subroutine for fold_truthop: decode a field reference.
If EXP is a comparison reference, we return the innermost reference.
*PBITSIZE is set to the number of bits in the reference, *PBITPOS is
set to the starting bit number.
If the innermost field can be completely contained in a mode-sized
unit, *PMODE is set to that mode. Otherwise, it is set to VOIDmode.
*PVOLATILEP is set to 1 if the any expression encountered is volatile;
otherwise it is not changed.
*PUNSIGNEDP is set to the signedness of the field.
*PMASK is set to the mask used. This is either contained in a
BIT_AND_EXPR or derived from the width of the field.
*PAND_MASK is set to the mask found in a BIT_AND_EXPR, if any.
Return 0 if this is not a component reference or is one that we can't
do anything with. */
static tree
decode_field_reference (exp, pbitsize, pbitpos, pmode, punsignedp,
pvolatilep, pmask, pand_mask)
tree exp;
HOST_WIDE_INT *pbitsize, *pbitpos;
enum machine_mode *pmode;
int *punsignedp, *pvolatilep;
tree *pmask;
tree *pand_mask;
{
tree and_mask = 0;
tree mask, inner, offset;
tree unsigned_type;
unsigned int precision;
/* All the optimizations using this function assume integer fields.
There are problems with FP fields since the type_for_size call
below can fail for, e.g., XFmode. */
if (! INTEGRAL_TYPE_P (TREE_TYPE (exp)))
return 0;
STRIP_NOPS (exp);
if (TREE_CODE (exp) == BIT_AND_EXPR)
{
and_mask = TREE_OPERAND (exp, 1);
exp = TREE_OPERAND (exp, 0);
STRIP_NOPS (exp); STRIP_NOPS (and_mask);
if (TREE_CODE (and_mask) != INTEGER_CST)
return 0;
}
inner = get_inner_reference (exp, pbitsize, pbitpos, &offset, pmode,
punsignedp, pvolatilep);
if ((inner == exp && and_mask == 0)
|| *pbitsize < 0 || offset != 0
|| TREE_CODE (inner) == PLACEHOLDER_EXPR)
return 0;
/* Compute the mask to access the bitfield. */
unsigned_type = type_for_size (*pbitsize, 1);
precision = TYPE_PRECISION (unsigned_type);
mask = build_int_2 (~0, ~0);
TREE_TYPE (mask) = unsigned_type;
force_fit_type (mask, 0);
mask = const_binop (LSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
mask = const_binop (RSHIFT_EXPR, mask, size_int (precision - *pbitsize), 0);
/* Merge it with the mask we found in the BIT_AND_EXPR, if any. */
if (and_mask != 0)
mask = fold (build (BIT_AND_EXPR, unsigned_type,
convert (unsigned_type, and_mask), mask));
*pmask = mask;
*pand_mask = and_mask;
return inner;
}
/* Return non-zero if MASK represents a mask of SIZE ones in the low-order
bit positions. */
static int
all_ones_mask_p (mask, size)
tree mask;
int size;
{
tree type = TREE_TYPE (mask);
unsigned int precision = TYPE_PRECISION (type);
tree tmask;
tmask = build_int_2 (~0, ~0);
TREE_TYPE (tmask) = signed_type (type);
force_fit_type (tmask, 0);
return
tree_int_cst_equal (mask,
const_binop (RSHIFT_EXPR,
const_binop (LSHIFT_EXPR, tmask,
size_int (precision - size),
0),
size_int (precision - size), 0));
}
/* Subroutine for fold_truthop: determine if an operand is simple enough
to be evaluated unconditionally. */
static int
simple_operand_p (exp)
tree exp;
{
/* Strip any conversions that don't change the machine mode. */
while ((TREE_CODE (exp) == NOP_EXPR
|| TREE_CODE (exp) == CONVERT_EXPR)
&& (TYPE_MODE (TREE_TYPE (exp))
== TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)))))
exp = TREE_OPERAND (exp, 0);
return (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c'
|| (DECL_P (exp)
&& ! TREE_ADDRESSABLE (exp)
&& ! TREE_THIS_VOLATILE (exp)
&& ! DECL_NONLOCAL (exp)
/* Don't regard global variables as simple. They may be
allocated in ways unknown to the compiler (shared memory,
#pragma weak, etc). */
&& ! TREE_PUBLIC (exp)
&& ! DECL_EXTERNAL (exp)
/* Loading a static variable is unduly expensive, but global
registers aren't expensive. */
&& (! TREE_STATIC (exp) || DECL_REGISTER (exp))));
}
/* The following functions are subroutines to fold_range_test and allow it to
try to change a logical combination of comparisons into a range test.
For example, both
X == 2 || X == 3 || X == 4 || X == 5
and
X >= 2 && X <= 5
are converted to
(unsigned) (X - 2) <= 3
We describe each set of comparisons as being either inside or outside
a range, using a variable named like IN_P, and then describe the
range with a lower and upper bound. If one of the bounds is omitted,
it represents either the highest or lowest value of the type.
In the comments below, we represent a range by two numbers in brackets
preceded by a "+" to designate being inside that range, or a "-" to
designate being outside that range, so the condition can be inverted by
flipping the prefix. An omitted bound is represented by a "-". For
example, "- [-, 10]" means being outside the range starting at the lowest
possible value and ending at 10, in other words, being greater than 10.
The range "+ [-, -]" is always true and hence the range "- [-, -]" is
always false.
We set up things so that the missing bounds are handled in a consistent
manner so neither a missing bound nor "true" and "false" need to be
handled using a special case. */
/* Return the result of applying CODE to ARG0 and ARG1, but handle the case
of ARG0 and/or ARG1 being omitted, meaning an unlimited range. UPPER0_P
and UPPER1_P are nonzero if the respective argument is an upper bound
and zero for a lower. TYPE, if nonzero, is the type of the result; it
must be specified for a comparison. ARG1 will be converted to ARG0's
type if both are specified. */
static tree
range_binop (code, type, arg0, upper0_p, arg1, upper1_p)
enum tree_code code;
tree type;
tree arg0, arg1;
int upper0_p, upper1_p;
{
tree tem;
int result;
int sgn0, sgn1;
/* If neither arg represents infinity, do the normal operation.
Else, if not a comparison, return infinity. Else handle the special
comparison rules. Note that most of the cases below won't occur, but
are handled for consistency. */
if (arg0 != 0 && arg1 != 0)
{
tem = fold (build (code, type != 0 ? type : TREE_TYPE (arg0),
arg0, convert (TREE_TYPE (arg0), arg1)));
STRIP_NOPS (tem);
return TREE_CODE (tem) == INTEGER_CST ? tem : 0;
}
if (TREE_CODE_CLASS (code) != '<')
return 0;
/* Set SGN[01] to -1 if ARG[01] is a lower bound, 1 for upper, and 0
for neither. In real maths, we cannot assume open ended ranges are
the same. But, this is computer arithmetic, where numbers are finite.
We can therefore make the transformation of any unbounded range with
the value Z, Z being greater than any representable number. This permits
us to treat unbounded ranges as equal. */
sgn0 = arg0 != 0 ? 0 : (upper0_p ? 1 : -1);
sgn1 = arg1 != 0 ? 0 : (upper1_p ? 1 : -1);
switch (code)
{
case EQ_EXPR:
result = sgn0 == sgn1;
break;
case NE_EXPR:
result = sgn0 != sgn1;
break;
case LT_EXPR:
result = sgn0 < sgn1;
break;
case LE_EXPR:
result = sgn0 <= sgn1;
break;
case GT_EXPR:
result = sgn0 > sgn1;
break;
case GE_EXPR:
result = sgn0 >= sgn1;
break;
default:
abort ();
}
return convert (type, result ? integer_one_node : integer_zero_node);
}
/* Given EXP, a logical expression, set the range it is testing into
variables denoted by PIN_P, PLOW, and PHIGH. Return the expression
actually being tested. *PLOW and *PHIGH will be made of the same type
as the returned expression. If EXP is not a comparison, we will most
likely not be returning a useful value and range. */
static tree
make_range (exp, pin_p, plow, phigh)
tree exp;
int *pin_p;
tree *plow, *phigh;
{
enum tree_code code;
tree arg0 = NULL_TREE, arg1 = NULL_TREE, type = NULL_TREE;
tree orig_type = NULL_TREE;
int in_p, n_in_p;
tree low, high, n_low, n_high;
/* Start with simply saying "EXP != 0" and then look at the code of EXP
and see if we can refine the range. Some of the cases below may not
happen, but it doesn't seem worth worrying about this. We "continue"
the outer loop when we've changed something; otherwise we "break"
the switch, which will "break" the while. */
in_p = 0, low = high = convert (TREE_TYPE (exp), integer_zero_node);
while (1)
{
code = TREE_CODE (exp);
if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code)))
{
arg0 = TREE_OPERAND (exp, 0);
if (TREE_CODE_CLASS (code) == '<'
|| TREE_CODE_CLASS (code) == '1'
|| TREE_CODE_CLASS (code) == '2')
type = TREE_TYPE (arg0);
if (TREE_CODE_CLASS (code) == '2'
|| TREE_CODE_CLASS (code) == '<'
|| (TREE_CODE_CLASS (code) == 'e'
&& TREE_CODE_LENGTH (code) > 1))
arg1 = TREE_OPERAND (exp, 1);
}
/* Set ORIG_TYPE as soon as TYPE is non-null so that we do not
lose a cast by accident. */
if (type != NULL_TREE && orig_type == NULL_TREE)
orig_type = type;
switch (code)
{
case TRUTH_NOT_EXPR:
in_p = ! in_p, exp = arg0;
continue;
case EQ_EXPR: case NE_EXPR:
case LT_EXPR: case LE_EXPR: case GE_EXPR: case GT_EXPR:
/* We can only do something if the range is testing for zero
and if the second operand is an integer constant. Note that
saying something is "in" the range we make is done by
complementing IN_P since it will set in the initial case of
being not equal to zero; "out" is leaving it alone. */
if (low == 0 || high == 0
|| ! integer_zerop (low) || ! integer_zerop (high)
|| TREE_CODE (arg1) != INTEGER_CST)
break;
switch (code)
{
case NE_EXPR: /* - [c, c] */
low = high = arg1;
break;
case EQ_EXPR: /* + [c, c] */
in_p = ! in_p, low = high = arg1;
break;
case GT_EXPR: /* - [-, c] */
low = 0, high = arg1;
break;
case GE_EXPR: /* + [c, -] */
in_p = ! in_p, low = arg1, high = 0;
break;
case LT_EXPR: /* - [c, -] */
low = arg1, high = 0;
break;
case LE_EXPR: /* + [-, c] */
in_p = ! in_p, low = 0, high = arg1;
break;
default:
abort ();
}
exp = arg0;
/* If this is an unsigned comparison, we also know that EXP is
greater than or equal to zero. We base the range tests we make
on that fact, so we record it here so we can parse existing
range tests. */
if (TREE_UNSIGNED (type) && (low == 0 || high == 0))
{
if (! merge_ranges (&n_in_p, &n_low, &n_high, in_p, low, high,
1, convert (type, integer_zero_node),
NULL_TREE))
break;
in_p = n_in_p, low = n_low, high = n_high;
/* If the high bound is missing, but we
have a low bound, reverse the range so
it goes from zero to the low bound minus 1. */
if (high == 0 && low)
{
in_p = ! in_p;
high = range_binop (MINUS_EXPR, NULL_TREE, low, 0,
integer_one_node, 0);
low = convert (type, integer_zero_node);
}
}
continue;
case NEGATE_EXPR:
/* (-x) IN [a,b] -> x in [-b, -a] */
n_low = range_binop (MINUS_EXPR, type,
convert (type, integer_zero_node), 0, high, 1);
n_high = range_binop (MINUS_EXPR, type,
convert (type, integer_zero_node), 0, low, 0);
low = n_low, high = n_high;
exp = arg0;
continue;
case BIT_NOT_EXPR:
/* ~ X -> -X - 1 */
exp = build (MINUS_EXPR, type, negate_expr (arg0),
convert (type, integer_one_node));
continue;
case PLUS_EXPR: case MINUS_EXPR:
if (TREE_CODE (arg1) != INTEGER_CST)
break;
/* If EXP is signed, any overflow in the computation is undefined,
so we don't worry about it so long as our computations on
the bounds don't overflow. For unsigned, overflow is defined
and this is exactly the right thing. */
n_low = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
type, low, 0, arg1, 0);
n_high = range_binop (code == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR,
type, high, 1, arg1, 0);
if ((n_low != 0 && TREE_OVERFLOW (n_low))
|| (n_high != 0 && TREE_OVERFLOW (n_high)))
break;
/* Check for an unsigned range which has wrapped around the maximum
value thus making n_high < n_low, and normalize it. */
if (n_low && n_high && tree_int_cst_lt (n_high, n_low))
{
low = range_binop (PLUS_EXPR, type, n_high, 0,
integer_one_node, 0);
high = range_binop (MINUS_EXPR, type, n_low, 0,
integer_one_node, 0);
/* If the range is of the form +/- [ x+1, x ], we won't
be able to normalize it. But then, it represents the
whole range or the empty set, so make it
+/- [ -, - ]. */
if (tree_int_cst_equal (n_low, low)
&& tree_int_cst_equal (n_high, high))
low = high = 0;
else
in_p = ! in_p;
}
else
low = n_low, high = n_high;
exp = arg0;
continue;
case NOP_EXPR: case NON_LVALUE_EXPR: case CONVERT_EXPR:
if (TYPE_PRECISION (type) > TYPE_PRECISION (orig_type))
break;
if (! INTEGRAL_TYPE_P (type)
|| (low != 0 && ! int_fits_type_p (low, type))
|| (high != 0 && ! int_fits_type_p (high, type)))
break;
n_low = low, n_high = high;
if (n_low != 0)
n_low = convert (type, n_low);
if (n_high != 0)
n_high = convert (type, n_high);
/* If we're converting from an unsigned to a signed type,
we will be doing the comparison as unsigned. The tests above
have already verified that LOW and HIGH are both positive.
So we have to make sure that the original unsigned value will
be interpreted as positive. */
if (TREE_UNSIGNED (type) && ! TREE_UNSIGNED (TREE_TYPE (exp)))
{
tree equiv_type = type_for_mode (TYPE_MODE (type), 1);
tree high_positive;
/* A range without an upper bound is, naturally, unbounded.
Since convert would have cropped a very large value, use
the max value for the destination type. */
high_positive
= TYPE_MAX_VALUE (equiv_type) ? TYPE_MAX_VALUE (equiv_type)
: TYPE_MAX_VALUE (type);
high_positive = fold (build (RSHIFT_EXPR, type,
convert (type, high_positive),
convert (type, integer_one_node)));
/* If the low bound is specified, "and" the range with the
range for which the original unsigned value will be
positive. */
if (low != 0)
{
if (! merge_ranges (&n_in_p, &n_low, &n_high,
1, n_low, n_high,
1, convert (type, integer_zero_node),
high_positive))
break;
in_p = (n_in_p == in_p);
}
else
{
/* Otherwise, "or" the range with the range of the input
that will be interpreted as negative. */
if (! merge_ranges (&n_in_p, &n_low, &n_high,
0, n_low, n_high,
1, convert (type, integer_zero_node),
high_positive))
break;
in_p = (in_p != n_in_p);
}
}
exp = arg0;
low = n_low, high = n_high;
continue;
default:
break;
}
break;
}
/* If EXP is a constant, we can evaluate whether this is true or false. */
if (TREE_CODE (exp) == INTEGER_CST)
{
in_p = in_p == (integer_onep (range_binop (GE_EXPR, integer_type_node,
exp, 0, low, 0))
&& integer_onep (range_binop (LE_EXPR, integer_type_node,
exp, 1, high, 1)));
low = high = 0;
exp = 0;
}
*pin_p = in_p, *plow = low, *phigh = high;
return exp;
}
/* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result
type, TYPE, return an expression to test if EXP is in (or out of, depending
on IN_P) the range. */
static tree
build_range_check (type, exp, in_p, low, high)
tree type;
tree exp;
int in_p;
tree low, high;
{
tree etype = TREE_TYPE (exp);
tree utype, value;
if (! in_p
&& (0 != (value = build_range_check (type, exp, 1, low, high))))
return invert_truthvalue (value);
else if (low == 0 && high == 0)
return convert (type, integer_one_node);
else if (low == 0)
return fold (build (LE_EXPR, type, exp, high));
else if (high == 0)
return fold (build (GE_EXPR, type, exp, low));
else if (operand_equal_p (low, high, 0))
return fold (build (EQ_EXPR, type, exp, low));
else if (TREE_UNSIGNED (etype) && integer_zerop (low))
return build_range_check (type, exp, 1, 0, high);
else if (integer_zerop (low))
{
utype = unsigned_type (etype);
return build_range_check (type, convert (utype, exp), 1, 0,
convert (utype, high));
}
else if (0 != (value = const_binop (MINUS_EXPR, high, low, 0))
&& ! TREE_OVERFLOW (value))
return build_range_check (type,
fold (build (MINUS_EXPR, etype, exp, low)),
1, convert (etype, integer_zero_node), value);
else
return 0;
}
/* Given two ranges, see if we can merge them into one. Return 1 if we
can, 0 if we can't. Set the output range into the specified parameters. */
static int
merge_ranges (pin_p, plow, phigh, in0_p, low0, high0, in1_p, low1, high1)
int *pin_p;
tree *plow, *phigh;
int in0_p, in1_p;
tree low0, high0, low1, high1;
{
int no_overlap;
int subset;
int temp;
tree tem;
int in_p;
tree low, high;
int lowequal = ((low0 == 0 && low1 == 0)
|| integer_onep (range_binop (EQ_EXPR, integer_type_node,
low0, 0, low1, 0)));
int highequal = ((high0 == 0 && high1 == 0)
|| integer_onep (range_binop (EQ_EXPR, integer_type_node,
high0, 1, high1, 1)));
/* Make range 0 be the range that starts first, or ends last if they
start at the same value. Swap them if it isn't. */
if (integer_onep (range_binop (GT_EXPR, integer_type_node,
low0, 0, low1, 0))
|| (lowequal
&& integer_onep (range_binop (GT_EXPR, integer_type_node,
high1, 1, high0, 1))))
{
temp = in0_p, in0_p = in1_p, in1_p = temp;
tem = low0, low0 = low1, low1 = tem;
tem = high0, high0 = high1, high1 = tem;
}
/* Now flag two cases, whether the ranges are disjoint or whether the
second range is totally subsumed in the first. Note that the tests
below are simplified by the ones above. */
no_overlap = integer_onep (range_binop (LT_EXPR, integer_type_node,
high0, 1, low1, 0));
subset = integer_onep (range_binop (LE_EXPR, integer_type_node,
high1, 1, high0, 1));
/* We now have four cases, depending on whether we are including or
excluding the two ranges. */
if (in0_p && in1_p)
{
/* If they don't overlap, the result is false. If the second range
is a subset it is the result. Otherwise, the range is from the start
of the second to the end of the first. */
if (no_overlap)
in_p = 0, low = high = 0;
else if (subset)
in_p = 1, low = low1, high = high1;
else
in_p = 1, low = low1, high = high0;
}
else if (in0_p && ! in1_p)
{
/* If they don't overlap, the result is the first range. If they are
equal, the result is false. If the second range is a subset of the
first, and the ranges begin at the same place, we go from just after
the end of the first range to the end of the second. If the second
range is not a subset of the first, or if it is a subset and both
ranges end at the same place, the range starts at the start of the
first range and ends just before the second range.
Otherwise, we can't describe this as a single range. */
if (no_overlap)
in_p = 1, low = low0, high = high0;
else if (lowequal && highequal)
in_p = 0, low = high = 0;
else if (subset && lowequal)
{
in_p = 1, high = high0;
low = range_binop (PLUS_EXPR, NULL_TREE, high1, 0,
integer_one_node, 0);
}
else if (! subset || highequal)
{
in_p = 1, low = low0;
high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0,
integer_one_node, 0);
}
else
return 0;
}
else if (! in0_p && in1_p)
{
/* If they don't overlap, the result is the second range. If the second
is a subset of the first, the result is false. Otherwise,
the range starts just after the first range and ends at the
end of the second. */
if (no_overlap)
in_p = 1, low = low1, high = high1;
else if (subset || highequal)
in_p = 0, low = high = 0;
else
{
in_p = 1, high = high1;
low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1,
integer_one_node, 0);
}
}
else
{
/* The case where we are excluding both ranges. Here the complex case
is if they don't overlap. In that case, the only time we have a
range is if they are adjacent. If the second is a subset of the
first, the result is the first. Otherwise, the range to exclude
starts at the beginning of the first range and ends at the end of the
second. */
if (no_overlap)
{
if (integer_onep (range_binop (EQ_EXPR, integer_type_node,
range_binop (PLUS_EXPR, NULL_TREE,
high0, 1,
integer_one_node, 1),
1, low1, 0)))
in_p = 0, low = low0, high = high1;
else
return 0;
}
else if (subset)
in_p = 0, low = low0, high = high0;
else
in_p = 0, low = low0, high = high1;
}
*pin_p = in_p, *plow = low, *phigh = high;
return 1;
}
/* EXP is some logical combination of boolean tests. See if we can
merge it into some range test. Return the new tree if so. */
static tree
fold_range_test (exp)
tree exp;
{
int or_op = (TREE_CODE (exp) == TRUTH_ORIF_EXPR
|| TREE_CODE (exp) == TRUTH_OR_EXPR);
int in0_p, in1_p, in_p;
tree low0, low1, low, high0, high1, high;
tree lhs = make_range (TREE_OPERAND (exp, 0), &in0_p, &low0, &high0);
tree rhs = make_range (TREE_OPERAND (exp, 1), &in1_p, &low1, &high1);
tree tem;
/* If this is an OR operation, invert both sides; we will invert
again at the end. */
if (or_op)
in0_p = ! in0_p, in1_p = ! in1_p;
/* If both expressions are the same, if we can merge the ranges, and we
can build the range test, return it or it inverted. If one of the
ranges is always true or always false, consider it to be the same
expression as the other. */
if ((lhs == 0 || rhs == 0 || operand_equal_p (lhs, rhs, 0))
&& merge_ranges (&in_p, &low, &high, in0_p, low0, high0,
in1_p, low1, high1)
&& 0 != (tem = (build_range_check (TREE_TYPE (exp),
lhs != 0 ? lhs
: rhs != 0 ? rhs : integer_zero_node,
in_p, low, high))))
return or_op ? invert_truthvalue (tem) : tem;
/* On machines where the branch cost is expensive, if this is a
short-circuited branch and the underlying object on both sides
is the same, make a non-short-circuit operation. */
else if (BRANCH_COST >= 2
&& lhs != 0 && rhs != 0
&& (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
|| TREE_CODE (exp) == TRUTH_ORIF_EXPR)
&& operand_equal_p (lhs, rhs, 0))
{
/* If simple enough, just rewrite. Otherwise, make a SAVE_EXPR
unless we are at top level or LHS contains a PLACEHOLDER_EXPR, in
which cases we can't do this. */
if (simple_operand_p (lhs))
return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
TREE_TYPE (exp), TREE_OPERAND (exp, 0),
TREE_OPERAND (exp, 1));
else if (global_bindings_p () == 0
&& ! contains_placeholder_p (lhs))
{
tree common = save_expr (lhs);
if (0 != (lhs = build_range_check (TREE_TYPE (exp), common,
or_op ? ! in0_p : in0_p,
low0, high0))
&& (0 != (rhs = build_range_check (TREE_TYPE (exp), common,
or_op ? ! in1_p : in1_p,
low1, high1))))
return build (TREE_CODE (exp) == TRUTH_ANDIF_EXPR
? TRUTH_AND_EXPR : TRUTH_OR_EXPR,
TREE_TYPE (exp), lhs, rhs);
}
}
return 0;
}
/* Subroutine for fold_truthop: C is an INTEGER_CST interpreted as a P
bit value. Arrange things so the extra bits will be set to zero if and
only if C is signed-extended to its full width. If MASK is nonzero,
it is an INTEGER_CST that should be AND'ed with the extra bits. */
static tree
unextend (c, p, unsignedp, mask)
tree c;
int p;
int unsignedp;
tree mask;
{
tree type = TREE_TYPE (c);
int modesize = GET_MODE_BITSIZE (TYPE_MODE (type));
tree temp;
if (p == modesize || unsignedp)
return c;
/* We work by getting just the sign bit into the low-order bit, then
into the high-order bit, then sign-extend. We then XOR that value
with C. */
temp = const_binop (RSHIFT_EXPR, c, size_int (p - 1), 0);
temp = const_binop (BIT_AND_EXPR, temp, size_int (1), 0);
/* We must use a signed type in order to get an arithmetic right shift.
However, we must also avoid introducing accidental overflows, so that
a subsequent call to integer_zerop will work. Hence we must
do the type conversion here. At this point, the constant is either
zero or one, and the conversion to a signed type can never overflow.
We could get an overflow if this conversion is done anywhere else. */
if (TREE_UNSIGNED (type))
temp = convert (signed_type (type), temp);
temp = const_binop (LSHIFT_EXPR, temp, size_int (modesize - 1), 0);
temp = const_binop (RSHIFT_EXPR, temp, size_int (modesize - p - 1), 0);
if (mask != 0)
temp = const_binop (BIT_AND_EXPR, temp, convert (TREE_TYPE (c), mask), 0);
/* If necessary, convert the type back to match the type of C. */
if (TREE_UNSIGNED (type))
temp = convert (type, temp);
return convert (type, const_binop (BIT_XOR_EXPR, c, temp, 0));
}
/* Find ways of folding logical expressions of LHS and RHS:
Try to merge two comparisons to the same innermost item.
Look for range tests like "ch >= '0' && ch <= '9'".
Look for combinations of simple terms on machines with expensive branches
and evaluate the RHS unconditionally.
For example, if we have p->a == 2 && p->b == 4 and we can make an
object large enough to span both A and B, we can do this with a comparison
against the object ANDed with the a mask.
If we have p->a == q->a && p->b == q->b, we may be able to use bit masking
operations to do this with one comparison.
We check for both normal comparisons and the BIT_AND_EXPRs made this by
function and the one above.
CODE is the logical operation being done. It can be TRUTH_ANDIF_EXPR,
TRUTH_AND_EXPR, TRUTH_ORIF_EXPR, or TRUTH_OR_EXPR.
TRUTH_TYPE is the type of the logical operand and LHS and RHS are its
two operands.
We return the simplified tree or 0 if no optimization is possible. */
static tree
fold_truthop (code, truth_type, lhs, rhs)
enum tree_code code;
tree truth_type, lhs, rhs;
{
/* If this is the "or" of two comparisons, we can do something if
the comparisons are NE_EXPR. If this is the "and", we can do something
if the comparisons are EQ_EXPR. I.e.,
(a->b == 2 && a->c == 4) can become (a->new == NEW).
WANTED_CODE is this operation code. For single bit fields, we can
convert EQ_EXPR to NE_EXPR so we need not reject the "wrong"
comparison for one-bit fields. */
enum tree_code wanted_code;
enum tree_code lcode, rcode;
tree ll_arg, lr_arg, rl_arg, rr_arg;
tree ll_inner, lr_inner, rl_inner, rr_inner;
HOST_WIDE_INT ll_bitsize, ll_bitpos, lr_bitsize, lr_bitpos;
HOST_WIDE_INT rl_bitsize, rl_bitpos, rr_bitsize, rr_bitpos;
HOST_WIDE_INT xll_bitpos, xlr_bitpos, xrl_bitpos, xrr_bitpos;
HOST_WIDE_INT lnbitsize, lnbitpos, rnbitsize, rnbitpos;
int ll_unsignedp, lr_unsignedp, rl_unsignedp, rr_unsignedp;
enum machine_mode ll_mode, lr_mode, rl_mode, rr_mode;
enum machine_mode lnmode, rnmode;
tree ll_mask, lr_mask, rl_mask, rr_mask;
tree ll_and_mask, lr_and_mask, rl_and_mask, rr_and_mask;
tree l_const, r_const;
tree lntype, rntype, result;
int first_bit, end_bit;
int volatilep;
/* Start by getting the comparison codes. Fail if anything is volatile.
If one operand is a BIT_AND_EXPR with the constant one, treat it as if
it were surrounded with a NE_EXPR. */
if (TREE_SIDE_EFFECTS (lhs) || TREE_SIDE_EFFECTS (rhs))
return 0;
lcode = TREE_CODE (lhs);
rcode = TREE_CODE (rhs);
if (lcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (lhs, 1)))
lcode = NE_EXPR, lhs = build (NE_EXPR, truth_type, lhs, integer_zero_node);
if (rcode == BIT_AND_EXPR && integer_onep (TREE_OPERAND (rhs, 1)))
rcode = NE_EXPR, rhs = build (NE_EXPR, truth_type, rhs, integer_zero_node);
if (TREE_CODE_CLASS (lcode) != '<' || TREE_CODE_CLASS (rcode) != '<')
return 0;
code = ((code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR)
? TRUTH_AND_EXPR : TRUTH_OR_EXPR);
ll_arg = TREE_OPERAND (lhs, 0);
lr_arg = TREE_OPERAND (lhs, 1);
rl_arg = TREE_OPERAND (rhs, 0);
rr_arg = TREE_OPERAND (rhs, 1);
/* If the RHS can be evaluated unconditionally and its operands are
simple, it wins to evaluate the RHS unconditionally on machines
with expensive branches. In this case, this isn't a comparison
that can be merged. Avoid doing this if the RHS is a floating-point
comparison since those can trap. */
if (BRANCH_COST >= 2
&& ! FLOAT_TYPE_P (TREE_TYPE (rl_arg))
&& simple_operand_p (rl_arg)
&& simple_operand_p (rr_arg))
return build (code, truth_type, lhs, rhs);
/* See if the comparisons can be merged. Then get all the parameters for
each side. */
if ((lcode != EQ_EXPR && lcode != NE_EXPR)
|| (rcode != EQ_EXPR && rcode != NE_EXPR))
return 0;
volatilep = 0;
ll_inner = decode_field_reference (ll_arg,
&ll_bitsize, &ll_bitpos, &ll_mode,
&ll_unsignedp, &volatilep, &ll_mask,
&ll_and_mask);
lr_inner = decode_field_reference (lr_arg,
&lr_bitsize, &lr_bitpos, &lr_mode,
&lr_unsignedp, &volatilep, &lr_mask,
&lr_and_mask);
rl_inner = decode_field_reference (rl_arg,
&rl_bitsize, &rl_bitpos, &rl_mode,
&rl_unsignedp, &volatilep, &rl_mask,
&rl_and_mask);
rr_inner = decode_field_reference (rr_arg,
&rr_bitsize, &rr_bitpos, &rr_mode,
&rr_unsignedp, &volatilep, &rr_mask,
&rr_and_mask);
/* It must be true that the inner operation on the lhs of each
comparison must be the same if we are to be able to do anything.
Then see if we have constants. If not, the same must be true for
the rhs's. */
if (volatilep || ll_inner == 0 || rl_inner == 0
|| ! operand_equal_p (ll_inner, rl_inner, 0))
return 0;
if (TREE_CODE (lr_arg) == INTEGER_CST
&& TREE_CODE (rr_arg) == INTEGER_CST)
l_const = lr_arg, r_const = rr_arg;
else if (lr_inner == 0 || rr_inner == 0
|| ! operand_equal_p (lr_inner, rr_inner, 0))
return 0;
else
l_const = r_const = 0;
/* If either comparison code is not correct for our logical operation,
fail. However, we can convert a one-bit comparison against zero into
the opposite comparison against that bit being set in the field. */
wanted_code = (code == TRUTH_AND_EXPR ? EQ_EXPR : NE_EXPR);
if (lcode != wanted_code)
{
if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask))
{
/* Make the left operand unsigned, since we are only interested
in the value of one bit. Otherwise we are doing the wrong
thing below. */
ll_unsignedp = 1;
l_const = ll_mask;
}
else
return 0;
}
/* This is analogous to the code for l_const above. */
if (rcode != wanted_code)
{
if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask))
{
rl_unsignedp = 1;
r_const = rl_mask;
}
else
return 0;
}
/* See if we can find a mode that contains both fields being compared on
the left. If we can't, fail. Otherwise, update all constants and masks
to be relative to a field of that size. */
first_bit = MIN (ll_bitpos, rl_bitpos);
end_bit = MAX (ll_bitpos + ll_bitsize, rl_bitpos + rl_bitsize);
lnmode = get_best_mode (end_bit - first_bit, first_bit,
TYPE_ALIGN (TREE_TYPE (ll_inner)), word_mode,
volatilep);
if (lnmode == VOIDmode)
return 0;
lnbitsize = GET_MODE_BITSIZE (lnmode);
lnbitpos = first_bit & ~ (lnbitsize - 1);
lntype = type_for_size (lnbitsize, 1);
xll_bitpos = ll_bitpos - lnbitpos, xrl_bitpos = rl_bitpos - lnbitpos;
if (BYTES_BIG_ENDIAN)
{
xll_bitpos = lnbitsize - xll_bitpos - ll_bitsize;
xrl_bitpos = lnbitsize - xrl_bitpos - rl_bitsize;
}
ll_mask = const_binop (LSHIFT_EXPR, convert (lntype, ll_mask),
size_int (xll_bitpos), 0);
rl_mask = const_binop (LSHIFT_EXPR, convert (lntype, rl_mask),
size_int (xrl_bitpos), 0);
if (l_const)
{
l_const = convert (lntype, l_const);
l_const = unextend (l_const, ll_bitsize, ll_unsignedp, ll_and_mask);
l_const = const_binop (LSHIFT_EXPR, l_const, size_int (xll_bitpos), 0);
if (! integer_zerop (const_binop (BIT_AND_EXPR, l_const,
fold (build1 (BIT_NOT_EXPR,
lntype, ll_mask)),
0)))
{
warning ("comparison is always %d", wanted_code == NE_EXPR);
return convert (truth_type,
wanted_code == NE_EXPR
? integer_one_node : integer_zero_node);
}
}
if (r_const)
{
r_const = convert (lntype, r_const);
r_const = unextend (r_const, rl_bitsize, rl_unsignedp, rl_and_mask);
r_const = const_binop (LSHIFT_EXPR, r_const, size_int (xrl_bitpos), 0);
if (! integer_zerop (const_binop (BIT_AND_EXPR, r_const,
fold (build1 (BIT_NOT_EXPR,
lntype, rl_mask)),
0)))
{
warning ("comparison is always %d", wanted_code == NE_EXPR);
return convert (truth_type,
wanted_code == NE_EXPR
? integer_one_node : integer_zero_node);
}
}
/* If the right sides are not constant, do the same for it. Also,
disallow this optimization if a size or signedness mismatch occurs
between the left and right sides. */
if (l_const == 0)
{
if (ll_bitsize != lr_bitsize || rl_bitsize != rr_bitsize
|| ll_unsignedp != lr_unsignedp || rl_unsignedp != rr_unsignedp
/* Make sure the two fields on the right
correspond to the left without being swapped. */
|| ll_bitpos - rl_bitpos != lr_bitpos - rr_bitpos)
return 0;
first_bit = MIN (lr_bitpos, rr_bitpos);
end_bit = MAX (lr_bitpos + lr_bitsize, rr_bitpos + rr_bitsize);
rnmode = get_best_mode (end_bit - first_bit, first_bit,
TYPE_ALIGN (TREE_TYPE (lr_inner)), word_mode,
volatilep);
if (rnmode == VOIDmode)
return 0;
rnbitsize = GET_MODE_BITSIZE (rnmode);
rnbitpos = first_bit & ~ (rnbitsize - 1);
rntype = type_for_size (rnbitsize, 1);
xlr_bitpos = lr_bitpos - rnbitpos, xrr_bitpos = rr_bitpos - rnbitpos;
if (BYTES_BIG_ENDIAN)
{
xlr_bitpos = rnbitsize - xlr_bitpos - lr_bitsize;
xrr_bitpos = rnbitsize - xrr_bitpos - rr_bitsize;
}
lr_mask = const_binop (LSHIFT_EXPR, convert (rntype, lr_mask),
size_int (xlr_bitpos), 0);
rr_mask = const_binop (LSHIFT_EXPR, convert (rntype, rr_mask),
size_int (xrr_bitpos), 0);
/* Make a mask that corresponds to both fields being compared.
Do this for both items being compared. If the operands are the
same size and the bits being compared are in the same position
then we can do this by masking both and comparing the masked
results. */
ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
lr_mask = const_binop (BIT_IOR_EXPR, lr_mask, rr_mask, 0);
if (lnbitsize == rnbitsize && xll_bitpos == xlr_bitpos)
{
lhs = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
ll_unsignedp || rl_unsignedp);
if (! all_ones_mask_p (ll_mask, lnbitsize))
lhs = build (BIT_AND_EXPR, lntype, lhs, ll_mask);
rhs = make_bit_field_ref (lr_inner, rntype, rnbitsize, rnbitpos,
lr_unsignedp || rr_unsignedp);
if (! all_ones_mask_p (lr_mask, rnbitsize))
rhs = build (BIT_AND_EXPR, rntype, rhs, lr_mask);
return build (wanted_code, truth_type, lhs, rhs);
}
/* There is still another way we can do something: If both pairs of
fields being compared are adjacent, we may be able to make a wider
field containing them both.
Note that we still must mask the lhs/rhs expressions. Furthermore,
the mask must be shifted to account for the shift done by
make_bit_field_ref. */
if ((ll_bitsize + ll_bitpos == rl_bitpos
&& lr_bitsize + lr_bitpos == rr_bitpos)
|| (ll_bitpos == rl_bitpos + rl_bitsize
&& lr_bitpos == rr_bitpos + rr_bitsize))
{
tree type;
lhs = make_bit_field_ref (ll_inner, lntype, ll_bitsize + rl_bitsize,
MIN (ll_bitpos, rl_bitpos), ll_unsignedp);
rhs = make_bit_field_ref (lr_inner, rntype, lr_bitsize + rr_bitsize,
MIN (lr_bitpos, rr_bitpos), lr_unsignedp);
ll_mask = const_binop (RSHIFT_EXPR, ll_mask,
size_int (MIN (xll_bitpos, xrl_bitpos)), 0);
lr_mask = const_binop (RSHIFT_EXPR, lr_mask,
size_int (MIN (xlr_bitpos, xrr_bitpos)), 0);
/* Convert to the smaller type before masking out unwanted bits. */
type = lntype;
if (lntype != rntype)
{
if (lnbitsize > rnbitsize)
{
lhs = convert (rntype, lhs);
ll_mask = convert (rntype, ll_mask);
type = rntype;
}
else if (lnbitsize < rnbitsize)
{
rhs = convert (lntype, rhs);
lr_mask = convert (lntype, lr_mask);
type = lntype;
}
}
if (! all_ones_mask_p (ll_mask, ll_bitsize + rl_bitsize))
lhs = build (BIT_AND_EXPR, type, lhs, ll_mask);
if (! all_ones_mask_p (lr_mask, lr_bitsize + rr_bitsize))
rhs = build (BIT_AND_EXPR, type, rhs, lr_mask);
return build (wanted_code, truth_type, lhs, rhs);
}
return 0;
}
/* Handle the case of comparisons with constants. If there is something in
common between the masks, those bits of the constants must be the same.
If not, the condition is always false. Test for this to avoid generating
incorrect code below. */
result = const_binop (BIT_AND_EXPR, ll_mask, rl_mask, 0);
if (! integer_zerop (result)
&& simple_cst_equal (const_binop (BIT_AND_EXPR, result, l_const, 0),
const_binop (BIT_AND_EXPR, result, r_const, 0)) != 1)
{
if (wanted_code == NE_EXPR)
{
warning ("`or' of unmatched not-equal tests is always 1");
return convert (truth_type, integer_one_node);
}
else
{
warning ("`and' of mutually exclusive equal-tests is always 0");
return convert (truth_type, integer_zero_node);
}
}
/* Construct the expression we will return. First get the component
reference we will make. Unless the mask is all ones the width of
that field, perform the mask operation. Then compare with the
merged constant. */
result = make_bit_field_ref (ll_inner, lntype, lnbitsize, lnbitpos,
ll_unsignedp || rl_unsignedp);
ll_mask = const_binop (BIT_IOR_EXPR, ll_mask, rl_mask, 0);
if (! all_ones_mask_p (ll_mask, lnbitsize))
result = build (BIT_AND_EXPR, lntype, result, ll_mask);
return build (wanted_code, truth_type, result,
const_binop (BIT_IOR_EXPR, l_const, r_const, 0));
}
/* Optimize T, which is a comparison of a MIN_EXPR or MAX_EXPR with a
constant. */
static tree
optimize_minmax_comparison (t)
tree t;
{
tree type = TREE_TYPE (t);
tree arg0 = TREE_OPERAND (t, 0);
enum tree_code op_code;
tree comp_const = TREE_OPERAND (t, 1);
tree minmax_const;
int consts_equal, consts_lt;
tree inner;
STRIP_SIGN_NOPS (arg0);
op_code = TREE_CODE (arg0);
minmax_const = TREE_OPERAND (arg0, 1);
consts_equal = tree_int_cst_equal (minmax_const, comp_const);
consts_lt = tree_int_cst_lt (minmax_const, comp_const);
inner = TREE_OPERAND (arg0, 0);
/* If something does not permit us to optimize, return the original tree. */
if ((op_code != MIN_EXPR && op_code != MAX_EXPR)
|| TREE_CODE (comp_const) != INTEGER_CST
|| TREE_CONSTANT_OVERFLOW (comp_const)
|| TREE_CODE (minmax_const) != INTEGER_CST
|| TREE_CONSTANT_OVERFLOW (minmax_const))
return t;
/* Now handle all the various comparison codes. We only handle EQ_EXPR
and GT_EXPR, doing the rest with recursive calls using logical
simplifications. */
switch (TREE_CODE (t))
{
case NE_EXPR: case LT_EXPR: case LE_EXPR:
return
invert_truthvalue (optimize_minmax_comparison (invert_truthvalue (t)));
case GE_EXPR:
return
fold (build (TRUTH_ORIF_EXPR, type,
optimize_minmax_comparison
(build (EQ_EXPR, type, arg0, comp_const)),
optimize_minmax_comparison
(build (GT_EXPR, type, arg0, comp_const))));
case EQ_EXPR:
if (op_code == MAX_EXPR && consts_equal)
/* MAX (X, 0) == 0 -> X <= 0 */
return fold (build (LE_EXPR, type, inner, comp_const));
else if (op_code == MAX_EXPR && consts_lt)
/* MAX (X, 0) == 5 -> X == 5 */
return fold (build (EQ_EXPR, type, inner, comp_const));
else if (op_code == MAX_EXPR)
/* MAX (X, 0) == -1 -> false */
return omit_one_operand (type, integer_zero_node, inner);
else if (consts_equal)
/* MIN (X, 0) == 0 -> X >= 0 */
return fold (build (GE_EXPR, type, inner, comp_const));
else if (consts_lt)
/* MIN (X, 0) == 5 -> false */
return omit_one_operand (type, integer_zero_node, inner);
else
/* MIN (X, 0) == -1 -> X == -1 */
return fold (build (EQ_EXPR, type, inner, comp_const));
case GT_EXPR:
if (op_code == MAX_EXPR && (consts_equal || consts_lt))
/* MAX (X, 0) > 0 -> X > 0
MAX (X, 0) > 5 -> X > 5 */
return fold (build (GT_EXPR, type, inner, comp_const));
else if (op_code == MAX_EXPR)
/* MAX (X, 0) > -1 -> true */
return omit_one_operand (type, integer_one_node, inner);
else if (op_code == MIN_EXPR && (consts_equal || consts_lt))
/* MIN (X, 0) > 0 -> false
MIN (X, 0) > 5 -> false */
return omit_one_operand (type, integer_zero_node, inner);
else
/* MIN (X, 0) > -1 -> X > -1 */
return fold (build (GT_EXPR, type, inner, comp_const));
default:
return t;
}
}
/* T is an integer expression that is being multiplied, divided, or taken a
modulus (CODE says which and what kind of divide or modulus) by a
constant C. See if we can eliminate that operation by folding it with
other operations already in T. WIDE_TYPE, if non-null, is a type that
should be used for the computation if wider than our type.
For example, if we are dividing (X * 8) + (Y + 16) by 4, we can return
(X * 2) + (Y + 4). We must, however, be assured that either the original
expression would not overflow or that overflow is undefined for the type
in the language in question.
We also canonicalize (X + 7) * 4 into X * 4 + 28 in the hope that either
the machine has a multiply-accumulate insn or that this is part of an
addressing calculation.
If we return a non-null expression, it is an equivalent form of the
original computation, but need not be in the original type. */
static tree
extract_muldiv (t, c, code, wide_type)
tree t;
tree c;
enum tree_code code;
tree wide_type;
{
tree type = TREE_TYPE (t);
enum tree_code tcode = TREE_CODE (t);
tree ctype = (wide_type != 0 && (GET_MODE_SIZE (TYPE_MODE (wide_type))
> GET_MODE_SIZE (TYPE_MODE (type)))
? wide_type : type);
tree t1, t2;
int same_p = tcode == code;
tree op0 = NULL_TREE, op1 = NULL_TREE;
/* Don't deal with constants of zero here; they confuse the code below. */
if (integer_zerop (c))
return NULL_TREE;
if (TREE_CODE_CLASS (tcode) == '1')
op0 = TREE_OPERAND (t, 0);
if (TREE_CODE_CLASS (tcode) == '2')
op0 = TREE_OPERAND (t, 0), op1 = TREE_OPERAND (t, 1);
/* Note that we need not handle conditional operations here since fold
already handles those cases. So just do arithmetic here. */
switch (tcode)
{
case INTEGER_CST:
/* For a constant, we can always simplify if we are a multiply
or (for divide and modulus) if it is a multiple of our constant. */
if (code == MULT_EXPR
|| integer_zerop (const_binop (TRUNC_MOD_EXPR, t, c, 0)))
return const_binop (code, convert (ctype, t), convert (ctype, c), 0);
break;
case CONVERT_EXPR: case NON_LVALUE_EXPR: case NOP_EXPR:
/* If op0 is an expression, and is unsigned, and the type is
smaller than ctype, then we cannot widen the expression. */
if ((TREE_CODE_CLASS (TREE_CODE (op0)) == '<'
|| TREE_CODE_CLASS (TREE_CODE (op0)) == '1'
|| TREE_CODE_CLASS (TREE_CODE (op0)) == '2'
|| TREE_CODE_CLASS (TREE_CODE (op0)) == 'e')
&& TREE_UNSIGNED (TREE_TYPE (op0))
&& ! (TREE_CODE (TREE_TYPE (op0)) == INTEGER_TYPE
&& TYPE_IS_SIZETYPE (TREE_TYPE (op0)))
&& (GET_MODE_SIZE (TYPE_MODE (ctype))
> GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0)))))
break;
/* Pass the constant down and see if we can make a simplification. If
we can, replace this expression with the inner simplification for
possible later conversion to our or some other type. */
if (0 != (t1 = extract_muldiv (op0, convert (TREE_TYPE (op0), c), code,
code == MULT_EXPR ? ctype : NULL_TREE)))
return t1;
break;
case NEGATE_EXPR: case ABS_EXPR:
if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
return fold (build1 (tcode, ctype, convert (ctype, t1)));
break;
case MIN_EXPR: case MAX_EXPR:
/* If widening the type changes the signedness, then we can't perform
this optimization as that changes the result. */
if (TREE_UNSIGNED (ctype) != TREE_UNSIGNED (type))
break;
/* MIN (a, b) / 5 -> MIN (a / 5, b / 5) */
if ((t1 = extract_muldiv (op0, c, code, wide_type)) != 0
&& (t2 = extract_muldiv (op1, c, code, wide_type)) != 0)
{
if (tree_int_cst_sgn (c) < 0)
tcode = (tcode == MIN_EXPR ? MAX_EXPR : MIN_EXPR);
return fold (build (tcode, ctype, convert (ctype, t1),
convert (ctype, t2)));
}
break;
case WITH_RECORD_EXPR:
if ((t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code, wide_type)) != 0)
return build (WITH_RECORD_EXPR, TREE_TYPE (t1), t1,
TREE_OPERAND (t, 1));
break;
case SAVE_EXPR:
/* If this has not been evaluated and the operand has no side effects,
we can see if we can do something inside it and make a new one.
Note that this test is overly conservative since we can do this
if the only reason it had side effects is that it was another
similar SAVE_EXPR, but that isn't worth bothering with. */
if (SAVE_EXPR_RTL (t) == 0 && ! TREE_SIDE_EFFECTS (TREE_OPERAND (t, 0))
&& 0 != (t1 = extract_muldiv (TREE_OPERAND (t, 0), c, code,
wide_type)))
{
t1 = save_expr (t1);
if (SAVE_EXPR_PERSISTENT_P (t) && TREE_CODE (t1) == SAVE_EXPR)
SAVE_EXPR_PERSISTENT_P (t1) = 1;
if (is_pending_size (t))
put_pending_size (t1);
return t1;
}
break;
case LSHIFT_EXPR: case RSHIFT_EXPR:
/* If the second operand is constant, this is a multiplication
or floor division, by a power of two, so we can treat it that
way unless the multiplier or divisor overflows. */
if (TREE_CODE (op1) == INTEGER_CST
/* const_binop may not detect overflow correctly,
so check for it explicitly here. */
&& TYPE_PRECISION (TREE_TYPE (size_one_node)) > TREE_INT_CST_LOW (op1)
&& TREE_INT_CST_HIGH (op1) == 0
&& 0 != (t1 = convert (ctype,
const_binop (LSHIFT_EXPR, size_one_node,
op1, 0)))
&& ! TREE_OVERFLOW (t1))
return extract_muldiv (build (tcode == LSHIFT_EXPR
? MULT_EXPR : FLOOR_DIV_EXPR,
ctype, convert (ctype, op0), t1),
c, code, wide_type);
break;
case PLUS_EXPR: case MINUS_EXPR:
/* See if we can eliminate the operation on both sides. If we can, we
can return a new PLUS or MINUS. If we can't, the only remaining
cases where we can do anything are if the second operand is a
constant. */
t1 = extract_muldiv (op0, c, code, wide_type);
t2 = extract_muldiv (op1, c, code, wide_type);
if (t1 != 0 && t2 != 0
&& (code == MULT_EXPR
/* If not multiplication, we can only do this if either operand
is divisible by c. */
|| multiple_of_p (ctype, op0, c)
|| multiple_of_p (ctype, op1, c)))
return fold (build (tcode, ctype, convert (ctype, t1),
convert (ctype, t2)));
/* If this was a subtraction, negate OP1 and set it to be an addition.
This simplifies the logic below. */
if (tcode == MINUS_EXPR)
tcode = PLUS_EXPR, op1 = negate_expr (op1);
if (TREE_CODE (op1) != INTEGER_CST)
break;
/* If either OP1 or C are negative, this optimization is not safe for
some of the division and remainder types while for others we need
to change the code. */
if (tree_int_cst_sgn (op1) < 0 || tree_int_cst_sgn (c) < 0)
{
if (code == CEIL_DIV_EXPR)
code = FLOOR_DIV_EXPR;
else if (code == FLOOR_DIV_EXPR)
code = CEIL_DIV_EXPR;
else if (code != MULT_EXPR
&& code != CEIL_MOD_EXPR && code != FLOOR_MOD_EXPR)
break;
}
/* If it's a multiply or a division/modulus operation of a multiple
of our constant, do the operation and verify it doesn't overflow. */
if (code == MULT_EXPR
|| integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
{
op1 = const_binop (code, convert (ctype, op1), convert (ctype, c), 0);
if (op1 == 0 || TREE_OVERFLOW (op1))
break;
}
else
break;
/* If we have an unsigned type is not a sizetype, we cannot widen
the operation since it will change the result if the original
computation overflowed. */
if (TREE_UNSIGNED (ctype)
&& ! (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype))
&& ctype != type)
break;
/* If we were able to eliminate our operation from the first side,
apply our operation to the second side and reform the PLUS. */
if (t1 != 0 && (TREE_CODE (t1) != code || code == MULT_EXPR))
return fold (build (tcode, ctype, convert (ctype, t1), op1));
/* The last case is if we are a multiply. In that case, we can
apply the distributive law to commute the multiply and addition
if the multiplication of the constants doesn't overflow. */
if (code == MULT_EXPR)
return fold (build (tcode, ctype, fold (build (code, ctype,
convert (ctype, op0),
convert (ctype, c))),
op1));
break;
case MULT_EXPR:
/* We have a special case here if we are doing something like
(C * 8) % 4 since we know that's zero. */
if ((code == TRUNC_MOD_EXPR || code == CEIL_MOD_EXPR
|| code == FLOOR_MOD_EXPR || code == ROUND_MOD_EXPR)
&& TREE_CODE (TREE_OPERAND (t, 1)) == INTEGER_CST
&& integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
return omit_one_operand (type, integer_zero_node, op0);
/* ... fall through ... */
case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR: case EXACT_DIV_EXPR:
/* If we can extract our operation from the LHS, do so and return a
new operation. Likewise for the RHS from a MULT_EXPR. Otherwise,
do something only if the second operand is a constant. */
if (same_p
&& (t1 = extract_muldiv (op0, c, code, wide_type)) != 0)
return fold (build (tcode, ctype, convert (ctype, t1),
convert (ctype, op1)));
else if (tcode == MULT_EXPR && code == MULT_EXPR
&& (t1 = extract_muldiv (op1, c, code, wide_type)) != 0)
return fold (build (tcode, ctype, convert (ctype, op0),
convert (ctype, t1)));
else if (TREE_CODE (op1) != INTEGER_CST)
return 0;
/* If these are the same operation types, we can associate them
assuming no overflow. */
if (tcode == code
&& 0 != (t1 = const_binop (MULT_EXPR, convert (ctype, op1),
convert (ctype, c), 0))
&& ! TREE_OVERFLOW (t1))
return fold (build (tcode, ctype, convert (ctype, op0), t1));
/* If these operations "cancel" each other, we have the main
optimizations of this pass, which occur when either constant is a
multiple of the other, in which case we replace this with either an
operation or CODE or TCODE.
If we have an unsigned type that is not a sizetype, we cannot do
this since it will change the result if the original computation
overflowed. */
if ((! TREE_UNSIGNED (ctype)
|| (TREE_CODE (ctype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (ctype)))
&& ((code == MULT_EXPR && tcode == EXACT_DIV_EXPR)
|| (tcode == MULT_EXPR
&& code != TRUNC_MOD_EXPR && code != CEIL_MOD_EXPR
&& code != FLOOR_MOD_EXPR && code != ROUND_MOD_EXPR)))
{
if (integer_zerop (const_binop (TRUNC_MOD_EXPR, op1, c, 0)))
return fold (build (tcode, ctype, convert (ctype, op0),
convert (ctype,
const_binop (TRUNC_DIV_EXPR,
op1, c, 0))));
else if (integer_zerop (const_binop (TRUNC_MOD_EXPR, c, op1, 0)))
return fold (build (code, ctype, convert (ctype, op0),
convert (ctype,
const_binop (TRUNC_DIV_EXPR,
c, op1, 0))));
}
break;
default:
break;
}
return 0;
}
/* If T contains a COMPOUND_EXPR which was inserted merely to evaluate
S, a SAVE_EXPR, return the expression actually being evaluated. Note
that we may sometimes modify the tree. */
static tree
strip_compound_expr (t, s)
tree t;
tree s;
{
enum tree_code code = TREE_CODE (t);
/* See if this is the COMPOUND_EXPR we want to eliminate. */
if (code == COMPOUND_EXPR && TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR
&& TREE_OPERAND (TREE_OPERAND (t, 0), 0) == s)
return TREE_OPERAND (t, 1);
/* See if this is a COND_EXPR or a simple arithmetic operator. We
don't bother handling any other types. */
else if (code == COND_EXPR)
{
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
TREE_OPERAND (t, 2) = strip_compound_expr (TREE_OPERAND (t, 2), s);
}
else if (TREE_CODE_CLASS (code) == '1')
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
else if (TREE_CODE_CLASS (code) == '<'
|| TREE_CODE_CLASS (code) == '2')
{
TREE_OPERAND (t, 0) = strip_compound_expr (TREE_OPERAND (t, 0), s);
TREE_OPERAND (t, 1) = strip_compound_expr (TREE_OPERAND (t, 1), s);
}
return t;
}
/* Return a node which has the indicated constant VALUE (either 0 or
1), and is of the indicated TYPE. */
static tree
constant_boolean_node (value, type)
int value;
tree type;
{
if (type == integer_type_node)
return value ? integer_one_node : integer_zero_node;
else if (TREE_CODE (type) == BOOLEAN_TYPE)
return truthvalue_conversion (value ? integer_one_node :
integer_zero_node);
else
{
tree t = build_int_2 (value, 0);
TREE_TYPE (t) = type;
return t;
}
}
/* Utility function for the following routine, to see how complex a nesting of
COND_EXPRs can be. EXPR is the expression and LIMIT is a count beyond which
we don't care (to avoid spending too much time on complex expressions.). */
static int
count_cond (expr, lim)
tree expr;
int lim;
{
int ctrue, cfalse;
if (TREE_CODE (expr) != COND_EXPR)
return 0;
else if (lim <= 0)
return 0;
ctrue = count_cond (TREE_OPERAND (expr, 1), lim - 1);
cfalse = count_cond (TREE_OPERAND (expr, 2), lim - 1 - ctrue);
return MIN (lim, 1 + ctrue + cfalse);
}
/* Transform `a + (b ? x : y)' into `x ? (a + b) : (a + y)'.
Transform, `a + (x < y)' into `(x < y) ? (a + 1) : (a + 0)'. Here
CODE corresponds to the `+', COND to the `(b ? x : y)' or `(x < y)'
expression, and ARG to `a'. If COND_FIRST_P is non-zero, then the
COND is the first argument to CODE; otherwise (as in the example
given here), it is the second argument. TYPE is the type of the
original expression. */
static tree
fold_binary_op_with_conditional_arg (code, type, cond, arg, cond_first_p)
enum tree_code code;
tree type;
tree cond;
tree arg;
int cond_first_p;
{
tree test, true_value, false_value;
tree lhs = NULL_TREE;
tree rhs = NULL_TREE;
/* In the end, we'll produce a COND_EXPR. Both arms of the
conditional expression will be binary operations. The left-hand
side of the expression to be executed if the condition is true
will be pointed to by TRUE_LHS. Similarly, the right-hand side
of the expression to be executed if the condition is true will be
pointed to by TRUE_RHS. FALSE_LHS and FALSE_RHS are analogous --
but apply to the expression to be executed if the conditional is
false. */
tree *true_lhs;
tree *true_rhs;
tree *false_lhs;
tree *false_rhs;
/* These are the codes to use for the left-hand side and right-hand
side of the COND_EXPR. Normally, they are the same as CODE. */
enum tree_code lhs_code = code;
enum tree_code rhs_code = code;
/* And these are the types of the expressions. */
tree lhs_type = type;
tree rhs_type = type;
if (cond_first_p)
{
true_rhs = false_rhs = &arg;
true_lhs = &true_value;
false_lhs = &false_value;
}
else
{
true_lhs = false_lhs = &arg;
true_rhs = &true_value;
false_rhs = &false_value;
}
if (TREE_CODE (cond) == COND_EXPR)
{
test = TREE_OPERAND (cond, 0);
true_value = TREE_OPERAND (cond, 1);
false_value = TREE_OPERAND (cond, 2);
/* If this operand throws an expression, then it does not make
sense to try to perform a logical or arithmetic operation
involving it. Instead of building `a + throw 3' for example,
we simply build `a, throw 3'. */
if (VOID_TYPE_P (TREE_TYPE (true_value)))
{
lhs_code = COMPOUND_EXPR;
if (!cond_first_p)
lhs_type = void_type_node;
}
if (VOID_TYPE_P (TREE_TYPE (false_value)))
{
rhs_code = COMPOUND_EXPR;
if (!cond_first_p)
rhs_type = void_type_node;
}
}
else
{
tree testtype = TREE_TYPE (cond);
test = cond;
true_value = convert (testtype, integer_one_node);
false_value = convert (testtype, integer_zero_node);
}
/* If ARG is complex we want to make sure we only evaluate
it once. Though this is only required if it is volatile, it
might be more efficient even if it is not. However, if we
succeed in folding one part to a constant, we do not need
to make this SAVE_EXPR. Since we do this optimization
primarily to see if we do end up with constant and this
SAVE_EXPR interferes with later optimizations, suppressing
it when we can is important.
If we are not in a function, we can't make a SAVE_EXPR, so don't
try to do so. Don't try to see if the result is a constant
if an arm is a COND_EXPR since we get exponential behavior
in that case. */
if (TREE_CODE (arg) != SAVE_EXPR && ! TREE_CONSTANT (arg)
&& global_bindings_p () == 0
&& ((TREE_CODE (arg) != VAR_DECL
&& TREE_CODE (arg) != PARM_DECL)
|| TREE_SIDE_EFFECTS (arg)))
{
if (TREE_CODE (true_value) != COND_EXPR)
lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
if (TREE_CODE (false_value) != COND_EXPR)
rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
if ((lhs == 0 || ! TREE_CONSTANT (lhs))
&& (rhs == 0 || !TREE_CONSTANT (rhs)))
arg = save_expr (arg), lhs = rhs = 0;
}
if (lhs == 0)
lhs = fold (build (lhs_code, lhs_type, *true_lhs, *true_rhs));
if (rhs == 0)
rhs = fold (build (rhs_code, rhs_type, *false_lhs, *false_rhs));
test = fold (build (COND_EXPR, type, test, lhs, rhs));
if (TREE_CODE (arg) == SAVE_EXPR)
return build (COMPOUND_EXPR, type,
convert (void_type_node, arg),
strip_compound_expr (test, arg));
else
return convert (type, test);
}
/* Perform constant folding and related simplification of EXPR.
The related simplifications include x*1 => x, x*0 => 0, etc.,
and application of the associative law.
NOP_EXPR conversions may be removed freely (as long as we
are careful not to change the C type of the overall expression)
We cannot simplify through a CONVERT_EXPR, FIX_EXPR or FLOAT_EXPR,
but we can constant-fold them if they have constant operands. */
tree
fold (expr)
tree expr;
{
tree t = expr;
tree t1 = NULL_TREE;
tree tem;
tree type = TREE_TYPE (expr);
tree arg0 = NULL_TREE, arg1 = NULL_TREE;
enum tree_code code = TREE_CODE (t);
int kind = TREE_CODE_CLASS (code);
int invert;
/* WINS will be nonzero when the switch is done
if all operands are constant. */
int wins = 1;
/* Don't try to process an RTL_EXPR since its operands aren't trees.
Likewise for a SAVE_EXPR that's already been evaluated. */
if (code == RTL_EXPR || (code == SAVE_EXPR && SAVE_EXPR_RTL (t) != 0))
return t;
/* Return right away if a constant. */
if (kind == 'c')
return t;
#ifdef MAX_INTEGER_COMPUTATION_MODE
check_max_integer_computation_mode (expr);
#endif
if (code == NOP_EXPR || code == FLOAT_EXPR || code == CONVERT_EXPR)
{
tree subop;
/* Special case for conversion ops that can have fixed point args. */
arg0 = TREE_OPERAND (t, 0);
/* Don't use STRIP_NOPS, because signedness of argument type matters. */
if (arg0 != 0)
STRIP_SIGN_NOPS (arg0);
if (arg0 != 0 && TREE_CODE (arg0) == COMPLEX_CST)
subop = TREE_REALPART (arg0);
else
subop = arg0;
if (subop != 0 && TREE_CODE (subop) != INTEGER_CST
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
&& TREE_CODE (subop) != REAL_CST
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
)
/* Note that TREE_CONSTANT isn't enough:
static var addresses are constant but we can't
do arithmetic on them. */
wins = 0;
}
else if (IS_EXPR_CODE_CLASS (kind) || kind == 'r')
{
int len = first_rtl_op (code);
int i;
for (i = 0; i < len; i++)
{
tree op = TREE_OPERAND (t, i);
tree subop;
if (op == 0)
continue; /* Valid for CALL_EXPR, at least. */
if (kind == '<' || code == RSHIFT_EXPR)
{
/* Signedness matters here. Perhaps we can refine this
later. */
STRIP_SIGN_NOPS (op);
}
else
/* Strip any conversions that don't change the mode. */
STRIP_NOPS (op);
if (TREE_CODE (op) == COMPLEX_CST)
subop = TREE_REALPART (op);
else
subop = op;
if (TREE_CODE (subop) != INTEGER_CST
#if ! defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
&& TREE_CODE (subop) != REAL_CST
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
)
/* Note that TREE_CONSTANT isn't enough:
static var addresses are constant but we can't
do arithmetic on them. */
wins = 0;
if (i == 0)
arg0 = op;
else if (i == 1)
arg1 = op;
}
}
/* If this is a commutative operation, and ARG0 is a constant, move it
to ARG1 to reduce the number of tests below. */
if ((code == PLUS_EXPR || code == MULT_EXPR || code == MIN_EXPR
|| code == MAX_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR
|| code == BIT_AND_EXPR)
&& (TREE_CODE (arg0) == INTEGER_CST || TREE_CODE (arg0) == REAL_CST))
{
tem = arg0; arg0 = arg1; arg1 = tem;
tem = TREE_OPERAND (t, 0); TREE_OPERAND (t, 0) = TREE_OPERAND (t, 1);
TREE_OPERAND (t, 1) = tem;
}
/* Now WINS is set as described above,
ARG0 is the first operand of EXPR,
and ARG1 is the second operand (if it has more than one operand).
First check for cases where an arithmetic operation is applied to a
compound, conditional, or comparison operation. Push the arithmetic
operation inside the compound or conditional to see if any folding
can then be done. Convert comparison to conditional for this purpose.
The also optimizes non-constant cases that used to be done in
expand_expr.
Before we do that, see if this is a BIT_AND_EXPR or a BIT_IOR_EXPR,
one of the operands is a comparison and the other is a comparison, a
BIT_AND_EXPR with the constant 1, or a truth value. In that case, the
code below would make the expression more complex. Change it to a
TRUTH_{AND,OR}_EXPR. Likewise, convert a similar NE_EXPR to
TRUTH_XOR_EXPR and an EQ_EXPR to the inversion of a TRUTH_XOR_EXPR. */
if ((code == BIT_AND_EXPR || code == BIT_IOR_EXPR
|| code == EQ_EXPR || code == NE_EXPR)
&& ((truth_value_p (TREE_CODE (arg0))
&& (truth_value_p (TREE_CODE (arg1))
|| (TREE_CODE (arg1) == BIT_AND_EXPR
&& integer_onep (TREE_OPERAND (arg1, 1)))))
|| (truth_value_p (TREE_CODE (arg1))
&& (truth_value_p (TREE_CODE (arg0))
|| (TREE_CODE (arg0) == BIT_AND_EXPR
&& integer_onep (TREE_OPERAND (arg0, 1)))))))
{
t = fold (build (code == BIT_AND_EXPR ? TRUTH_AND_EXPR
: code == BIT_IOR_EXPR ? TRUTH_OR_EXPR
: TRUTH_XOR_EXPR,
type, arg0, arg1));
if (code == EQ_EXPR)
t = invert_truthvalue (t);
return t;
}
if (TREE_CODE_CLASS (code) == '1')
{
if (TREE_CODE (arg0) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
fold (build1 (code, type, TREE_OPERAND (arg0, 1))));
else if (TREE_CODE (arg0) == COND_EXPR)
{
t = fold (build (COND_EXPR, type, TREE_OPERAND (arg0, 0),
fold (build1 (code, type, TREE_OPERAND (arg0, 1))),
fold (build1 (code, type, TREE_OPERAND (arg0, 2)))));
/* If this was a conversion, and all we did was to move into
inside the COND_EXPR, bring it back out. But leave it if
it is a conversion from integer to integer and the
result precision is no wider than a word since such a
conversion is cheap and may be optimized away by combine,
while it couldn't if it were outside the COND_EXPR. Then return
so we don't get into an infinite recursion loop taking the
conversion out and then back in. */
if ((code == NOP_EXPR || code == CONVERT_EXPR
|| code == NON_LVALUE_EXPR)
&& TREE_CODE (t) == COND_EXPR
&& TREE_CODE (TREE_OPERAND (t, 1)) == code
&& TREE_CODE (TREE_OPERAND (t, 2)) == code
&& (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))
== TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 2), 0)))
&& ! (INTEGRAL_TYPE_P (TREE_TYPE (t))
&& (INTEGRAL_TYPE_P
(TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 1), 0))))
&& TYPE_PRECISION (TREE_TYPE (t)) <= BITS_PER_WORD))
t = build1 (code, type,
build (COND_EXPR,
TREE_TYPE (TREE_OPERAND
(TREE_OPERAND (t, 1), 0)),
TREE_OPERAND (t, 0),
TREE_OPERAND (TREE_OPERAND (t, 1), 0),
TREE_OPERAND (TREE_OPERAND (t, 2), 0)));
return t;
}
else if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<')
return fold (build (COND_EXPR, type, arg0,
fold (build1 (code, type, integer_one_node)),
fold (build1 (code, type, integer_zero_node))));
}
else if (TREE_CODE_CLASS (code) == '2'
|| TREE_CODE_CLASS (code) == '<')
{
if (TREE_CODE (arg1) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
fold (build (code, type,
arg0, TREE_OPERAND (arg1, 1))));
else if ((TREE_CODE (arg1) == COND_EXPR
|| (TREE_CODE_CLASS (TREE_CODE (arg1)) == '<'
&& TREE_CODE_CLASS (code) != '<'))
&& (TREE_CODE (arg0) != COND_EXPR
|| count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
&& (! TREE_SIDE_EFFECTS (arg0)
|| (global_bindings_p () == 0
&& ! contains_placeholder_p (arg0))))
return
fold_binary_op_with_conditional_arg (code, type, arg1, arg0,
/*cond_first_p=*/0);
else if (TREE_CODE (arg0) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
else if ((TREE_CODE (arg0) == COND_EXPR
|| (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
&& TREE_CODE_CLASS (code) != '<'))
&& (TREE_CODE (arg1) != COND_EXPR
|| count_cond (arg0, 25) + count_cond (arg1, 25) <= 25)
&& (! TREE_SIDE_EFFECTS (arg1)
|| (global_bindings_p () == 0
&& ! contains_placeholder_p (arg1))))
return
fold_binary_op_with_conditional_arg (code, type, arg0, arg1,
/*cond_first_p=*/1);
}
else if (TREE_CODE_CLASS (code) == '<'
&& TREE_CODE (arg0) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg0, 0),
fold (build (code, type, TREE_OPERAND (arg0, 1), arg1)));
else if (TREE_CODE_CLASS (code) == '<'
&& TREE_CODE (arg1) == COMPOUND_EXPR)
return build (COMPOUND_EXPR, type, TREE_OPERAND (arg1, 0),
fold (build (code, type, arg0, TREE_OPERAND (arg1, 1))));
switch (code)
{
case INTEGER_CST:
case REAL_CST:
case STRING_CST:
case COMPLEX_CST:
case CONSTRUCTOR:
return t;
case CONST_DECL:
return fold (DECL_INITIAL (t));
case NOP_EXPR:
case FLOAT_EXPR:
case CONVERT_EXPR:
case FIX_TRUNC_EXPR:
/* Other kinds of FIX are not handled properly by fold_convert. */
if (TREE_TYPE (TREE_OPERAND (t, 0)) == TREE_TYPE (t))
return TREE_OPERAND (t, 0);
/* Handle cases of two conversions in a row. */
if (TREE_CODE (TREE_OPERAND (t, 0)) == NOP_EXPR
|| TREE_CODE (TREE_OPERAND (t, 0)) == CONVERT_EXPR)
{
tree inside_type = TREE_TYPE (TREE_OPERAND (TREE_OPERAND (t, 0), 0));
tree inter_type = TREE_TYPE (TREE_OPERAND (t, 0));
tree final_type = TREE_TYPE (t);
int inside_int = INTEGRAL_TYPE_P (inside_type);
int inside_ptr = POINTER_TYPE_P (inside_type);
int inside_float = FLOAT_TYPE_P (inside_type);
unsigned int inside_prec = TYPE_PRECISION (inside_type);
int inside_unsignedp = TREE_UNSIGNED (inside_type);
int inter_int = INTEGRAL_TYPE_P (inter_type);
int inter_ptr = POINTER_TYPE_P (inter_type);
int inter_float = FLOAT_TYPE_P (inter_type);
unsigned int inter_prec = TYPE_PRECISION (inter_type);
int inter_unsignedp = TREE_UNSIGNED (inter_type);
int final_int = INTEGRAL_TYPE_P (final_type);
int final_ptr = POINTER_TYPE_P (final_type);
int final_float = FLOAT_TYPE_P (final_type);
unsigned int final_prec = TYPE_PRECISION (final_type);
int final_unsignedp = TREE_UNSIGNED (final_type);
/* In addition to the cases of two conversions in a row
handled below, if we are converting something to its own
type via an object of identical or wider precision, neither
conversion is needed. */
if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (final_type)
&& ((inter_int && final_int) || (inter_float && final_float))
&& inter_prec >= final_prec)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
/* Likewise, if the intermediate and final types are either both
float or both integer, we don't need the middle conversion if
it is wider than the final type and doesn't change the signedness
(for integers). Avoid this if the final type is a pointer
since then we sometimes need the inner conversion. Likewise if
the outer has a precision not equal to the size of its mode. */
if ((((inter_int || inter_ptr) && (inside_int || inside_ptr))
|| (inter_float && inside_float))
&& inter_prec >= inside_prec
&& (inter_float || inter_unsignedp == inside_unsignedp)
&& ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
&& TYPE_MODE (final_type) == TYPE_MODE (inter_type))
&& ! final_ptr)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
/* If we have a sign-extension of a zero-extended value, we can
replace that by a single zero-extension. */
if (inside_int && inter_int && final_int
&& inside_prec < inter_prec && inter_prec < final_prec
&& inside_unsignedp && !inter_unsignedp)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
/* Two conversions in a row are not needed unless:
- some conversion is floating-point (overstrict for now), or
- the intermediate type is narrower than both initial and
final, or
- the intermediate type and innermost type differ in signedness,
and the outermost type is wider than the intermediate, or
- the initial type is a pointer type and the precisions of the
intermediate and final types differ, or
- the final type is a pointer type and the precisions of the
initial and intermediate types differ. */
if (! inside_float && ! inter_float && ! final_float
&& (inter_prec > inside_prec || inter_prec > final_prec)
&& ! (inside_int && inter_int
&& inter_unsignedp != inside_unsignedp
&& inter_prec < final_prec)
&& ((inter_unsignedp && inter_prec > inside_prec)
== (final_unsignedp && final_prec > inter_prec))
&& ! (inside_ptr && inter_prec != final_prec)
&& ! (final_ptr && inside_prec != inter_prec)
&& ! (final_prec != GET_MODE_BITSIZE (TYPE_MODE (final_type))
&& TYPE_MODE (final_type) == TYPE_MODE (inter_type))
&& ! final_ptr)
return convert (final_type, TREE_OPERAND (TREE_OPERAND (t, 0), 0));
}
if (TREE_CODE (TREE_OPERAND (t, 0)) == MODIFY_EXPR
&& TREE_CONSTANT (TREE_OPERAND (TREE_OPERAND (t, 0), 1))
/* Detect assigning a bitfield. */
&& !(TREE_CODE (TREE_OPERAND (TREE_OPERAND (t, 0), 0)) == COMPONENT_REF
&& DECL_BIT_FIELD (TREE_OPERAND (TREE_OPERAND (TREE_OPERAND (t, 0), 0), 1))))
{
/* Don't leave an assignment inside a conversion
unless assigning a bitfield. */
tree prev = TREE_OPERAND (t, 0);
TREE_OPERAND (t, 0) = TREE_OPERAND (prev, 1);
/* First do the assignment, then return converted constant. */
t = build (COMPOUND_EXPR, TREE_TYPE (t), prev, fold (t));
TREE_USED (t) = 1;
return t;
}
if (!wins)
{
TREE_CONSTANT (t) = TREE_CONSTANT (arg0);
return t;
}
return fold_convert (t, arg0);
case VIEW_CONVERT_EXPR:
if (TREE_CODE (TREE_OPERAND (t, 0)) == VIEW_CONVERT_EXPR)
return build1 (VIEW_CONVERT_EXPR, type,
TREE_OPERAND (TREE_OPERAND (t, 0), 0));
return t;
#if 0 /* This loses on &"foo"[0]. */
case ARRAY_REF:
{
int i;
/* Fold an expression like: "foo"[2] */
if (TREE_CODE (arg0) == STRING_CST
&& TREE_CODE (arg1) == INTEGER_CST
&& compare_tree_int (arg1, TREE_STRING_LENGTH (arg0)) < 0)
{
t = build_int_2 (TREE_STRING_POINTER (arg0)[TREE_INT_CST_LOW (arg))], 0);
TREE_TYPE (t) = TREE_TYPE (TREE_TYPE (arg0));
force_fit_type (t, 0);
}
}
return t;
#endif /* 0 */
case COMPONENT_REF:
if (TREE_CODE (arg0) == CONSTRUCTOR)
{
tree m = purpose_member (arg1, CONSTRUCTOR_ELTS (arg0));
if (m)
t = TREE_VALUE (m);
}
return t;
case RANGE_EXPR:
TREE_CONSTANT (t) = wins;
return t;
case NEGATE_EXPR:
if (wins)
{
if (TREE_CODE (arg0) == INTEGER_CST)
{
unsigned HOST_WIDE_INT low;
HOST_WIDE_INT high;
int overflow = neg_double (TREE_INT_CST_LOW (arg0),
TREE_INT_CST_HIGH (arg0),
&low, &high);
t = build_int_2 (low, high);
TREE_TYPE (t) = type;
TREE_OVERFLOW (t)
= (TREE_OVERFLOW (arg0)
| force_fit_type (t, overflow && !TREE_UNSIGNED (type)));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
}
else if (TREE_CODE (arg0) == REAL_CST)
t = build_real (type, REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
}
else if (TREE_CODE (arg0) == NEGATE_EXPR)
return TREE_OPERAND (arg0, 0);
/* Convert - (a - b) to (b - a) for non-floating-point. */
else if (TREE_CODE (arg0) == MINUS_EXPR
&& (! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations))
return build (MINUS_EXPR, type, TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg0, 0));
return t;
case ABS_EXPR:
if (wins)
{
if (TREE_CODE (arg0) == INTEGER_CST)
{
/* If the value is unsigned, then the absolute value is
the same as the ordinary value. */
if (TREE_UNSIGNED (type))
return arg0;
/* Similarly, if the value is non-negative. */
else if (INT_CST_LT (integer_minus_one_node, arg0))
return arg0;
/* If the value is negative, then the absolute value is
its negation. */
else
{
unsigned HOST_WIDE_INT low;
HOST_WIDE_INT high;
int overflow = neg_double (TREE_INT_CST_LOW (arg0),
TREE_INT_CST_HIGH (arg0),
&low, &high);
t = build_int_2 (low, high);
TREE_TYPE (t) = type;
TREE_OVERFLOW (t)
= (TREE_OVERFLOW (arg0)
| force_fit_type (t, overflow));
TREE_CONSTANT_OVERFLOW (t)
= TREE_OVERFLOW (t) | TREE_CONSTANT_OVERFLOW (arg0);
}
}
else if (TREE_CODE (arg0) == REAL_CST)
{
if (REAL_VALUE_NEGATIVE (TREE_REAL_CST (arg0)))
t = build_real (type,
REAL_VALUE_NEGATE (TREE_REAL_CST (arg0)));
}
}
else if (TREE_CODE (arg0) == ABS_EXPR || TREE_CODE (arg0) == NEGATE_EXPR)
return build1 (ABS_EXPR, type, TREE_OPERAND (arg0, 0));
return t;
case CONJ_EXPR:
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
return convert (type, arg0);
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
return build (COMPLEX_EXPR, type,
TREE_OPERAND (arg0, 0),
negate_expr (TREE_OPERAND (arg0, 1)));
else if (TREE_CODE (arg0) == COMPLEX_CST)
return build_complex (type, TREE_REALPART (arg0),
negate_expr (TREE_IMAGPART (arg0)));
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
return fold (build (TREE_CODE (arg0), type,
fold (build1 (CONJ_EXPR, type,
TREE_OPERAND (arg0, 0))),
fold (build1 (CONJ_EXPR,
type, TREE_OPERAND (arg0, 1)))));
else if (TREE_CODE (arg0) == CONJ_EXPR)
return TREE_OPERAND (arg0, 0);
return t;
case BIT_NOT_EXPR:
if (wins)
{
t = build_int_2 (~ TREE_INT_CST_LOW (arg0),
~ TREE_INT_CST_HIGH (arg0));
TREE_TYPE (t) = type;
force_fit_type (t, 0);
TREE_OVERFLOW (t) = TREE_OVERFLOW (arg0);
TREE_CONSTANT_OVERFLOW (t) = TREE_CONSTANT_OVERFLOW (arg0);
}
else if (TREE_CODE (arg0) == BIT_NOT_EXPR)
return TREE_OPERAND (arg0, 0);
return t;
case PLUS_EXPR:
/* A + (-B) -> A - B */
if (TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (MINUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
/* (-A) + B -> B - A */
if (TREE_CODE (arg0) == NEGATE_EXPR)
return fold (build (MINUS_EXPR, type, arg1, TREE_OPERAND (arg0, 0)));
else if (! FLOAT_TYPE_P (type))
{
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* If we are adding two BIT_AND_EXPR's, both of which are and'ing
with a constant, and the two constants have no bits in common,
we should treat this as a BIT_IOR_EXPR since this may produce more
simplifications. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& TREE_CODE (arg1) == BIT_AND_EXPR
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
&& TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
&& integer_zerop (const_binop (BIT_AND_EXPR,
TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0)))
{
code = BIT_IOR_EXPR;
goto bit_ior;
}
/* Reassociate (plus (plus (mult) (foo)) (mult)) as
(plus (plus (mult) (mult)) (foo)) so that we can
take advantage of the factoring cases below. */
if ((TREE_CODE (arg0) == PLUS_EXPR
&& TREE_CODE (arg1) == MULT_EXPR)
|| (TREE_CODE (arg1) == PLUS_EXPR
&& TREE_CODE (arg0) == MULT_EXPR))
{
tree parg0, parg1, parg, marg;
if (TREE_CODE (arg0) == PLUS_EXPR)
parg = arg0, marg = arg1;
else
parg = arg1, marg = arg0;
parg0 = TREE_OPERAND (parg, 0);
parg1 = TREE_OPERAND (parg, 1);
STRIP_NOPS (parg0);
STRIP_NOPS (parg1);
if (TREE_CODE (parg0) == MULT_EXPR
&& TREE_CODE (parg1) != MULT_EXPR)
return fold (build (PLUS_EXPR, type,
fold (build (PLUS_EXPR, type, parg0, marg)),
parg1));
if (TREE_CODE (parg0) != MULT_EXPR
&& TREE_CODE (parg1) == MULT_EXPR)
return fold (build (PLUS_EXPR, type,
fold (build (PLUS_EXPR, type, parg1, marg)),
parg0));
}
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR)
{
tree arg00, arg01, arg10, arg11;
tree alt0 = NULL_TREE, alt1 = NULL_TREE, same;
/* (A * C) + (B * C) -> (A+B) * C.
We are most concerned about the case where C is a constant,
but other combinations show up during loop reduction. Since
it is not difficult, try all four possibilities. */
arg00 = TREE_OPERAND (arg0, 0);
arg01 = TREE_OPERAND (arg0, 1);
arg10 = TREE_OPERAND (arg1, 0);
arg11 = TREE_OPERAND (arg1, 1);
same = NULL_TREE;
if (operand_equal_p (arg01, arg11, 0))
same = arg01, alt0 = arg00, alt1 = arg10;
else if (operand_equal_p (arg00, arg10, 0))
same = arg00, alt0 = arg01, alt1 = arg11;
else if (operand_equal_p (arg00, arg11, 0))
same = arg00, alt0 = arg01, alt1 = arg10;
else if (operand_equal_p (arg01, arg10, 0))
same = arg01, alt0 = arg00, alt1 = arg11;
/* No identical multiplicands; see if we can find a common
power-of-two factor in non-power-of-two multiplies. This
can help in multi-dimensional array access. */
else if (TREE_CODE (arg01) == INTEGER_CST
&& TREE_CODE (arg11) == INTEGER_CST
&& TREE_INT_CST_HIGH (arg01) == 0
&& TREE_INT_CST_HIGH (arg11) == 0)
{
HOST_WIDE_INT int01, int11, tmp;
int01 = TREE_INT_CST_LOW (arg01);
int11 = TREE_INT_CST_LOW (arg11);
/* Move min of absolute values to int11. */
if ((int01 >= 0 ? int01 : -int01)
< (int11 >= 0 ? int11 : -int11))
{
tmp = int01, int01 = int11, int11 = tmp;
alt0 = arg00, arg00 = arg10, arg10 = alt0;
alt0 = arg01, arg01 = arg11, arg11 = alt0;
}
if (exact_log2 (int11) > 0 && int01 % int11 == 0)
{
alt0 = fold (build (MULT_EXPR, type, arg00,
build_int_2 (int01 / int11, 0)));
alt1 = arg10;
same = arg11;
}
}
if (same)
return fold (build (MULT_EXPR, type,
fold (build (PLUS_EXPR, type, alt0, alt1)),
same));
}
}
/* In IEEE floating point, x+0 may not equal x. */
else if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|| flag_unsafe_math_optimizations)
&& real_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* x+(-0) equals x, even for IEEE. */
else if (TREE_CODE (arg1) == REAL_CST
&& REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
return non_lvalue (convert (type, arg0));
bit_rotate:
/* (A << C1) + (A >> C2) if A is unsigned and C1+C2 is the size of A
is a rotate of A by C1 bits. */
/* (A << B) + (A >> (Z - B)) if A is unsigned and Z is the size of A
is a rotate of A by B bits. */
{
enum tree_code code0, code1;
code0 = TREE_CODE (arg0);
code1 = TREE_CODE (arg1);
if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR)
|| (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR))
&& operand_equal_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0), 0)
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
{
tree tree01, tree11;
enum tree_code code01, code11;
tree01 = TREE_OPERAND (arg0, 1);
tree11 = TREE_OPERAND (arg1, 1);
STRIP_NOPS (tree01);
STRIP_NOPS (tree11);
code01 = TREE_CODE (tree01);
code11 = TREE_CODE (tree11);
if (code01 == INTEGER_CST
&& code11 == INTEGER_CST
&& TREE_INT_CST_HIGH (tree01) == 0
&& TREE_INT_CST_HIGH (tree11) == 0
&& ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11))
== TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)))))
return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0),
code0 == LSHIFT_EXPR ? tree01 : tree11);
else if (code11 == MINUS_EXPR)
{
tree tree110, tree111;
tree110 = TREE_OPERAND (tree11, 0);
tree111 = TREE_OPERAND (tree11, 1);
STRIP_NOPS (tree110);
STRIP_NOPS (tree111);
if (TREE_CODE (tree110) == INTEGER_CST
&& 0 == compare_tree_int (tree110,
TYPE_PRECISION
(TREE_TYPE (TREE_OPERAND
(arg0, 0))))
&& operand_equal_p (tree01, tree111, 0))
return build ((code0 == LSHIFT_EXPR
? LROTATE_EXPR
: RROTATE_EXPR),
type, TREE_OPERAND (arg0, 0), tree01);
}
else if (code01 == MINUS_EXPR)
{
tree tree010, tree011;
tree010 = TREE_OPERAND (tree01, 0);
tree011 = TREE_OPERAND (tree01, 1);
STRIP_NOPS (tree010);
STRIP_NOPS (tree011);
if (TREE_CODE (tree010) == INTEGER_CST
&& 0 == compare_tree_int (tree010,
TYPE_PRECISION
(TREE_TYPE (TREE_OPERAND
(arg0, 0))))
&& operand_equal_p (tree11, tree011, 0))
return build ((code0 != LSHIFT_EXPR
? LROTATE_EXPR
: RROTATE_EXPR),
type, TREE_OPERAND (arg0, 0), tree11);
}
}
}
associate:
/* In most languages, can't associate operations on floats through
parentheses. Rather than remember where the parentheses were, we
don't associate floats at all. It shouldn't matter much. However,
associating multiplications is only very slightly inaccurate, so do
that if -funsafe-math-optimizations is specified. */
if (! wins
&& (! FLOAT_TYPE_P (type)
|| (flag_unsafe_math_optimizations && code == MULT_EXPR)))
{
tree var0, con0, lit0, var1, con1, lit1;
/* Split both trees into variables, constants, and literals. Then
associate each group together, the constants with literals,
then the result with variables. This increases the chances of
literals being recombined later and of generating relocatable
expressions for the sum of a constant and literal. */
var0 = split_tree (arg0, code, &con0, &lit0, 0);
var1 = split_tree (arg1, code, &con1, &lit1, code == MINUS_EXPR);
/* Only do something if we found more than two objects. Otherwise,
nothing has changed and we risk infinite recursion. */
if (2 < ((var0 != 0) + (var1 != 0) + (con0 != 0) + (con1 != 0)
+ (lit0 != 0) + (lit1 != 0)))
{
var0 = associate_trees (var0, var1, code, type);
con0 = associate_trees (con0, con1, code, type);
lit0 = associate_trees (lit0, lit1, code, type);
con0 = associate_trees (con0, lit0, code, type);
return convert (type, associate_trees (var0, con0, code, type));
}
}
binary:
#if defined (REAL_IS_NOT_DOUBLE) && ! defined (REAL_ARITHMETIC)
if (TREE_CODE (arg1) == REAL_CST)
return t;
#endif /* REAL_IS_NOT_DOUBLE, and no REAL_ARITHMETIC */
if (wins)
t1 = const_binop (code, arg0, arg1, 0);
if (t1 != NULL_TREE)
{
/* The return value should always have
the same type as the original expression. */
if (TREE_TYPE (t1) != TREE_TYPE (t))
t1 = convert (TREE_TYPE (t), t1);
return t1;
}
return t;
case MINUS_EXPR:
/* A - (-B) -> A + B */
if (TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (PLUS_EXPR, type, arg0, TREE_OPERAND (arg1, 0)));
/* (-A) - CST -> (-CST) - A for floating point (what about ints ?) */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
return
fold (build (MINUS_EXPR, type,
build_real (TREE_TYPE (arg1),
REAL_VALUE_NEGATE (TREE_REAL_CST (arg1))),
TREE_OPERAND (arg0, 0)));
if (! FLOAT_TYPE_P (type))
{
if (! wins && integer_zerop (arg0))
return negate_expr (convert (type, arg1));
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* (A * C) - (B * C) -> (A-B) * C. Since we are most concerned
about the case where C is a constant, just try one of the
four possibilities. */
if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR
&& operand_equal_p (TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0))
return fold (build (MULT_EXPR, type,
fold (build (MINUS_EXPR, type,
TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0))),
TREE_OPERAND (arg0, 1)));
}
else if (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|| flag_unsafe_math_optimizations)
{
/* Except with IEEE floating point, 0-x equals -x. */
if (! wins && real_zerop (arg0))
return negate_expr (convert (type, arg1));
/* Except with IEEE floating point, x-0 equals x. */
if (real_zerop (arg1))
return non_lvalue (convert (type, arg0));
}
/* Fold &x - &x. This can happen from &x.foo - &x.
This is unsafe for certain floats even in non-IEEE formats.
In IEEE, it is unsafe because it does wrong for NaNs.
Also note that operand_equal_p is always false if an operand
is volatile. */
if ((! FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)
&& operand_equal_p (arg0, arg1, 0))
return convert (type, integer_zero_node);
goto associate;
case MULT_EXPR:
/* (-A) * (-B) -> A * B */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (MULT_EXPR, type, TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0)));
if (! FLOAT_TYPE_P (type))
{
if (integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
if (integer_onep (arg1))
return non_lvalue (convert (type, arg0));
/* (a * (1 << b)) is (a << b) */
if (TREE_CODE (arg1) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (arg1, 0)))
return fold (build (LSHIFT_EXPR, type, arg0,
TREE_OPERAND (arg1, 1)));
if (TREE_CODE (arg0) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (arg0, 0)))
return fold (build (LSHIFT_EXPR, type, arg1,
TREE_OPERAND (arg0, 1)));
if (TREE_CODE (arg1) == INTEGER_CST
&& 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
code, NULL_TREE)))
return convert (type, tem);
}
else
{
/* x*0 is 0, except for IEEE floating point. */
if ((TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|| flag_unsafe_math_optimizations)
&& real_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
/* In IEEE floating point, x*1 is not equivalent to x for snans.
However, ANSI says we can drop signals,
so we can do this anyway. */
if (real_onep (arg1))
return non_lvalue (convert (type, arg0));
/* x*2 is x+x */
if (! wins && real_twop (arg1) && global_bindings_p () == 0
&& ! contains_placeholder_p (arg0))
{
tree arg = save_expr (arg0);
return build (PLUS_EXPR, type, arg, arg);
}
}
goto associate;
case BIT_IOR_EXPR:
bit_ior:
if (integer_all_onesp (arg1))
return omit_one_operand (type, arg1, arg0);
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;
/* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
This results in more efficient code for machines without a NAND
instruction. Combine will canonicalize to the first form
which will allow use of NAND instructions provided by the
backend if they exist. */
if (TREE_CODE (arg0) == BIT_NOT_EXPR
&& TREE_CODE (arg1) == BIT_NOT_EXPR)
{
return fold (build1 (BIT_NOT_EXPR, type,
build (BIT_AND_EXPR, type,
TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0))));
}
/* See if this can be simplified into a rotate first. If that
is unsuccessful continue in the association code. */
goto bit_rotate;
case BIT_XOR_EXPR:
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
if (integer_all_onesp (arg1))
return fold (build1 (BIT_NOT_EXPR, type, arg0));
/* If we are XORing two BIT_AND_EXPR's, both of which are and'ing
with a constant, and the two constants have no bits in common,
we should treat this as a BIT_IOR_EXPR since this may produce more
simplifications. */
if (TREE_CODE (arg0) == BIT_AND_EXPR
&& TREE_CODE (arg1) == BIT_AND_EXPR
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
&& TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST
&& integer_zerop (const_binop (BIT_AND_EXPR,
TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg1, 1), 0)))
{
code = BIT_IOR_EXPR;
goto bit_ior;
}
/* See if this can be simplified into a rotate first. If that
is unsuccessful continue in the association code. */
goto bit_rotate;
case BIT_AND_EXPR:
bit_and:
if (integer_all_onesp (arg1))
return non_lvalue (convert (type, arg0));
if (integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
t1 = distribute_bit_expr (code, type, arg0, arg1);
if (t1 != NULL_TREE)
return t1;
/* Simplify ((int)c & 0x377) into (int)c, if c is unsigned char. */
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == NOP_EXPR
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))))
{
unsigned int prec
= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)));
if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
&& (~TREE_INT_CST_LOW (arg0)
& (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
return build1 (NOP_EXPR, type, TREE_OPERAND (arg1, 0));
}
if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) == NOP_EXPR
&& TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))))
{
unsigned int prec
= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0)));
if (prec < BITS_PER_WORD && prec < HOST_BITS_PER_WIDE_INT
&& (~TREE_INT_CST_LOW (arg1)
& (((HOST_WIDE_INT) 1 << prec) - 1)) == 0)
return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0));
}
/* Convert (and (not arg0) (not arg1)) to (not (or (arg0) (arg1))).
This results in more efficient code for machines without a NOR
instruction. Combine will canonicalize to the first form
which will allow use of NOR instructions provided by the
backend if they exist. */
if (TREE_CODE (arg0) == BIT_NOT_EXPR
&& TREE_CODE (arg1) == BIT_NOT_EXPR)
{
return fold (build1 (BIT_NOT_EXPR, type,
build (BIT_IOR_EXPR, type,
TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0))));
}
goto associate;
case BIT_ANDTC_EXPR:
if (integer_all_onesp (arg0))
return non_lvalue (convert (type, arg1));
if (integer_zerop (arg0))
return omit_one_operand (type, arg0, arg1);
if (TREE_CODE (arg1) == INTEGER_CST)
{
arg1 = fold (build1 (BIT_NOT_EXPR, type, arg1));
code = BIT_AND_EXPR;
goto bit_and;
}
goto binary;
case RDIV_EXPR:
/* In most cases, do nothing with a divide by zero. */
#if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
#ifndef REAL_INFINITY
if (TREE_CODE (arg1) == REAL_CST && real_zerop (arg1))
return t;
#endif
#endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
/* (-A) / (-B) -> A / B */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg1, 0)));
/* In IEEE floating point, x/1 is not equivalent to x for snans.
However, ANSI says we can drop signals, so we can do this anyway. */
if (real_onep (arg1))
return non_lvalue (convert (type, arg0));
/* If ARG1 is a constant, we can convert this to a multiply by the
reciprocal. This does not have the same rounding properties,
so only do this if -funsafe-math-optimizations. We can actually
always safely do it if ARG1 is a power of two, but it's hard to
tell if it is or not in a portable manner. */
if (TREE_CODE (arg1) == REAL_CST)
{
if (flag_unsafe_math_optimizations
&& 0 != (tem = const_binop (code, build_real (type, dconst1),
arg1, 0)))
return fold (build (MULT_EXPR, type, arg0, tem));
/* Find the reciprocal if optimizing and the result is exact. */
else if (optimize)
{
REAL_VALUE_TYPE r;
r = TREE_REAL_CST (arg1);
if (exact_real_inverse (TYPE_MODE(TREE_TYPE(arg0)), &r))
{
tem = build_real (type, r);
return fold (build (MULT_EXPR, type, arg0, tem));
}
}
}
/* Convert A/B/C to A/(B*C). */
if (flag_unsafe_math_optimizations
&& TREE_CODE (arg0) == RDIV_EXPR)
{
return fold (build (RDIV_EXPR, type, TREE_OPERAND (arg0, 0),
build (MULT_EXPR, type, TREE_OPERAND (arg0, 1),
arg1)));
}
/* Convert A/(B/C) to (A/B)*C. */
if (flag_unsafe_math_optimizations
&& TREE_CODE (arg1) == RDIV_EXPR)
{
return fold (build (MULT_EXPR, type,
build (RDIV_EXPR, type, arg0,
TREE_OPERAND (arg1, 0)),
TREE_OPERAND (arg1, 1)));
}
goto binary;
case TRUNC_DIV_EXPR:
case ROUND_DIV_EXPR:
case FLOOR_DIV_EXPR:
case CEIL_DIV_EXPR:
case EXACT_DIV_EXPR:
if (integer_onep (arg1))
return non_lvalue (convert (type, arg0));
if (integer_zerop (arg1))
return t;
/* If arg0 is a multiple of arg1, then rewrite to the fastest div
operation, EXACT_DIV_EXPR.
Note that only CEIL_DIV_EXPR and FLOOR_DIV_EXPR are rewritten now.
At one time others generated faster code, it's not clear if they do
after the last round to changes to the DIV code in expmed.c. */
if ((code == CEIL_DIV_EXPR || code == FLOOR_DIV_EXPR)
&& multiple_of_p (type, arg0, arg1))
return fold (build (EXACT_DIV_EXPR, type, arg0, arg1));
if (TREE_CODE (arg1) == INTEGER_CST
&& 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
code, NULL_TREE)))
return convert (type, tem);
goto binary;
case CEIL_MOD_EXPR:
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
case TRUNC_MOD_EXPR:
if (integer_onep (arg1))
return omit_one_operand (type, integer_zero_node, arg0);
if (integer_zerop (arg1))
return t;
if (TREE_CODE (arg1) == INTEGER_CST
&& 0 != (tem = extract_muldiv (TREE_OPERAND (t, 0), arg1,
code, NULL_TREE)))
return convert (type, tem);
goto binary;
case LSHIFT_EXPR:
case RSHIFT_EXPR:
case LROTATE_EXPR:
case RROTATE_EXPR:
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* Since negative shift count is not well-defined,
don't try to compute it in the compiler. */
if (TREE_CODE (arg1) == INTEGER_CST && tree_int_cst_sgn (arg1) < 0)
return t;
/* Rewrite an LROTATE_EXPR by a constant into an
RROTATE_EXPR by a new constant. */
if (code == LROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST)
{
TREE_SET_CODE (t, RROTATE_EXPR);
code = RROTATE_EXPR;
TREE_OPERAND (t, 1) = arg1
= const_binop
(MINUS_EXPR,
convert (TREE_TYPE (arg1),
build_int_2 (GET_MODE_BITSIZE (TYPE_MODE (type)), 0)),
arg1, 0);
if (tree_int_cst_sgn (arg1) < 0)
return t;
}
/* If we have a rotate of a bit operation with the rotate count and
the second operand of the bit operation both constant,
permute the two operations. */
if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
&& (TREE_CODE (arg0) == BIT_AND_EXPR
|| TREE_CODE (arg0) == BIT_ANDTC_EXPR
|| TREE_CODE (arg0) == BIT_IOR_EXPR
|| TREE_CODE (arg0) == BIT_XOR_EXPR)
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
return fold (build (TREE_CODE (arg0), type,
fold (build (code, type,
TREE_OPERAND (arg0, 0), arg1)),
fold (build (code, type,
TREE_OPERAND (arg0, 1), arg1))));
/* Two consecutive rotates adding up to the width of the mode can
be ignored. */
if (code == RROTATE_EXPR && TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg0) == RROTATE_EXPR
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
&& TREE_INT_CST_HIGH (arg1) == 0
&& TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0
&& ((TREE_INT_CST_LOW (arg1)
+ TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)))
== (unsigned int) GET_MODE_BITSIZE (TYPE_MODE (type))))
return TREE_OPERAND (arg0, 0);
goto binary;
case MIN_EXPR:
if (operand_equal_p (arg0, arg1, 0))
return omit_one_operand (type, arg0, arg1);
if (INTEGRAL_TYPE_P (type)
&& operand_equal_p (arg1, TYPE_MIN_VALUE (type), 1))
return omit_one_operand (type, arg1, arg0);
goto associate;
case MAX_EXPR:
if (operand_equal_p (arg0, arg1, 0))
return omit_one_operand (type, arg0, arg1);
if (INTEGRAL_TYPE_P (type)
&& TYPE_MAX_VALUE (type)
&& operand_equal_p (arg1, TYPE_MAX_VALUE (type), 1))
return omit_one_operand (type, arg1, arg0);
goto associate;
case TRUTH_NOT_EXPR:
/* Note that the operand of this must be an int
and its values must be 0 or 1.
("true" is a fixed value perhaps depending on the language,
but we don't handle values other than 1 correctly yet.) */
tem = invert_truthvalue (arg0);
/* Avoid infinite recursion. */
if (TREE_CODE (tem) == TRUTH_NOT_EXPR)
return t;
return convert (type, tem);
case TRUTH_ANDIF_EXPR:
/* Note that the operands of this must be ints
and their values must be 0 or 1.
("true" is a fixed value perhaps depending on the language.) */
/* If first arg is constant zero, return it. */
if (integer_zerop (arg0))
return convert (type, arg0);
case TRUTH_AND_EXPR:
/* If either arg is constant true, drop it. */
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
return non_lvalue (convert (type, arg1));
if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1)
/* Preserve sequence points. */
&& (code != TRUTH_ANDIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
return non_lvalue (convert (type, arg0));
/* If second arg is constant zero, result is zero, but first arg
must be evaluated. */
if (integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
/* Likewise for first arg, but note that only the TRUTH_AND_EXPR
case will be handled here. */
if (integer_zerop (arg0))
return omit_one_operand (type, arg0, arg1);
truth_andor:
/* We only do these simplifications if we are optimizing. */
if (!optimize)
return t;
/* Check for things like (A || B) && (A || C). We can convert this
to A || (B && C). Note that either operator can be any of the four
truth and/or operations and the transformation will still be
valid. Also note that we only care about order for the
ANDIF and ORIF operators. If B contains side effects, this
might change the truth-value of A. */
if (TREE_CODE (arg0) == TREE_CODE (arg1)
&& (TREE_CODE (arg0) == TRUTH_ANDIF_EXPR
|| TREE_CODE (arg0) == TRUTH_ORIF_EXPR
|| TREE_CODE (arg0) == TRUTH_AND_EXPR
|| TREE_CODE (arg0) == TRUTH_OR_EXPR)
&& ! TREE_SIDE_EFFECTS (TREE_OPERAND (arg0, 1)))
{
tree a00 = TREE_OPERAND (arg0, 0);
tree a01 = TREE_OPERAND (arg0, 1);
tree a10 = TREE_OPERAND (arg1, 0);
tree a11 = TREE_OPERAND (arg1, 1);
int commutative = ((TREE_CODE (arg0) == TRUTH_OR_EXPR
|| TREE_CODE (arg0) == TRUTH_AND_EXPR)
&& (code == TRUTH_AND_EXPR
|| code == TRUTH_OR_EXPR));
if (operand_equal_p (a00, a10, 0))
return fold (build (TREE_CODE (arg0), type, a00,
fold (build (code, type, a01, a11))));
else if (commutative && operand_equal_p (a00, a11, 0))
return fold (build (TREE_CODE (arg0), type, a00,
fold (build (code, type, a01, a10))));
else if (commutative && operand_equal_p (a01, a10, 0))
return fold (build (TREE_CODE (arg0), type, a01,
fold (build (code, type, a00, a11))));
/* This case if tricky because we must either have commutative
operators or else A10 must not have side-effects. */
else if ((commutative || ! TREE_SIDE_EFFECTS (a10))
&& operand_equal_p (a01, a11, 0))
return fold (build (TREE_CODE (arg0), type,
fold (build (code, type, a00, a10)),
a01));
}
/* See if we can build a range comparison. */
if (0 != (tem = fold_range_test (t)))
return tem;
/* Check for the possibility of merging component references. If our
lhs is another similar operation, try to merge its rhs with our
rhs. Then try to merge our lhs and rhs. */
if (TREE_CODE (arg0) == code
&& 0 != (tem = fold_truthop (code, type,
TREE_OPERAND (arg0, 1), arg1)))
return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
if ((tem = fold_truthop (code, type, arg0, arg1)) != 0)
return tem;
return t;
case TRUTH_ORIF_EXPR:
/* Note that the operands of this must be ints
and their values must be 0 or true.
("true" is a fixed value perhaps depending on the language.) */
/* If first arg is constant true, return it. */
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
return convert (type, arg0);
case TRUTH_OR_EXPR:
/* If either arg is constant zero, drop it. */
if (TREE_CODE (arg0) == INTEGER_CST && integer_zerop (arg0))
return non_lvalue (convert (type, arg1));
if (TREE_CODE (arg1) == INTEGER_CST && integer_zerop (arg1)
/* Preserve sequence points. */
&& (code != TRUTH_ORIF_EXPR || ! TREE_SIDE_EFFECTS (arg0)))
return non_lvalue (convert (type, arg0));
/* If second arg is constant true, result is true, but we must
evaluate first arg. */
if (TREE_CODE (arg1) == INTEGER_CST && ! integer_zerop (arg1))
return omit_one_operand (type, arg1, arg0);
/* Likewise for first arg, but note this only occurs here for
TRUTH_OR_EXPR. */
if (TREE_CODE (arg0) == INTEGER_CST && ! integer_zerop (arg0))
return omit_one_operand (type, arg0, arg1);
goto truth_andor;
case TRUTH_XOR_EXPR:
/* If either arg is constant zero, drop it. */
if (integer_zerop (arg0))
return non_lvalue (convert (type, arg1));
if (integer_zerop (arg1))
return non_lvalue (convert (type, arg0));
/* If either arg is constant true, this is a logical inversion. */
if (integer_onep (arg0))
return non_lvalue (convert (type, invert_truthvalue (arg1)));
if (integer_onep (arg1))
return non_lvalue (convert (type, invert_truthvalue (arg0)));
return t;
case EQ_EXPR:
case NE_EXPR:
case LT_EXPR:
case GT_EXPR:
case LE_EXPR:
case GE_EXPR:
if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
{
/* (-a) CMP (-b) -> b CMP a */
if (TREE_CODE (arg0) == NEGATE_EXPR
&& TREE_CODE (arg1) == NEGATE_EXPR)
return fold (build (code, type, TREE_OPERAND (arg1, 0),
TREE_OPERAND (arg0, 0)));
/* (-a) CMP CST -> a swap(CMP) (-CST) */
if (TREE_CODE (arg0) == NEGATE_EXPR && TREE_CODE (arg1) == REAL_CST)
return
fold (build
(swap_tree_comparison (code), type,
TREE_OPERAND (arg0, 0),
build_real (TREE_TYPE (arg1),
REAL_VALUE_NEGATE (TREE_REAL_CST (arg1)))));
/* IEEE doesn't distinguish +0 and -0 in comparisons. */
/* a CMP (-0) -> a CMP 0 */
if (TREE_CODE (arg1) == REAL_CST
&& REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (arg1)))
return fold (build (code, type, arg0,
build_real (TREE_TYPE (arg1), dconst0)));
}
/* If one arg is a constant integer, put it last. */
if (TREE_CODE (arg0) == INTEGER_CST
&& TREE_CODE (arg1) != INTEGER_CST)
{
TREE_OPERAND (t, 0) = arg1;
TREE_OPERAND (t, 1) = arg0;
arg0 = TREE_OPERAND (t, 0);
arg1 = TREE_OPERAND (t, 1);
code = swap_tree_comparison (code);
TREE_SET_CODE (t, code);
}
/* Convert foo++ == CONST into ++foo == CONST + INCR.
First, see if one arg is constant; find the constant arg
and the other one. */
{
tree constop = 0, varop = NULL_TREE;
int constopnum = -1;
if (TREE_CONSTANT (arg1))
constopnum = 1, constop = arg1, varop = arg0;
if (TREE_CONSTANT (arg0))
constopnum = 0, constop = arg0, varop = arg1;
if (constop && TREE_CODE (varop) == POSTINCREMENT_EXPR)
{
/* This optimization is invalid for ordered comparisons
if CONST+INCR overflows or if foo+incr might overflow.
This optimization is invalid for floating point due to rounding.
For pointer types we assume overflow doesn't happen. */
if (POINTER_TYPE_P (TREE_TYPE (varop))
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
&& (code == EQ_EXPR || code == NE_EXPR)))
{
tree newconst
= fold (build (PLUS_EXPR, TREE_TYPE (varop),
constop, TREE_OPERAND (varop, 1)));
/* Do not overwrite the current varop to be a preincrement,
create a new node so that we won't confuse our caller who
might create trees and throw them away, reusing the
arguments that they passed to build. This shows up in
the THEN or ELSE parts of ?: being postincrements. */
varop = build (PREINCREMENT_EXPR, TREE_TYPE (varop),
TREE_OPERAND (varop, 0),
TREE_OPERAND (varop, 1));
/* If VAROP is a reference to a bitfield, we must mask
the constant by the width of the field. */
if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
&& DECL_BIT_FIELD(TREE_OPERAND
(TREE_OPERAND (varop, 0), 1)))
{
int size
= TREE_INT_CST_LOW (DECL_SIZE
(TREE_OPERAND
(TREE_OPERAND (varop, 0), 1)));
tree mask, unsigned_type;
unsigned int precision;
tree folded_compare;
/* First check whether the comparison would come out
always the same. If we don't do that we would
change the meaning with the masking. */
if (constopnum == 0)
folded_compare = fold (build (code, type, constop,
TREE_OPERAND (varop, 0)));
else
folded_compare = fold (build (code, type,
TREE_OPERAND (varop, 0),
constop));
if (integer_zerop (folded_compare)
|| integer_onep (folded_compare))
return omit_one_operand (type, folded_compare, varop);
unsigned_type = type_for_size (size, 1);
precision = TYPE_PRECISION (unsigned_type);
mask = build_int_2 (~0, ~0);
TREE_TYPE (mask) = unsigned_type;
force_fit_type (mask, 0);
mask = const_binop (RSHIFT_EXPR, mask,
size_int (precision - size), 0);
newconst = fold (build (BIT_AND_EXPR,
TREE_TYPE (varop), newconst,
convert (TREE_TYPE (varop),
mask)));
}
t = build (code, type,
(constopnum == 0) ? newconst : varop,
(constopnum == 1) ? newconst : varop);
return t;
}
}
else if (constop && TREE_CODE (varop) == POSTDECREMENT_EXPR)
{
if (POINTER_TYPE_P (TREE_TYPE (varop))
|| (! FLOAT_TYPE_P (TREE_TYPE (varop))
&& (code == EQ_EXPR || code == NE_EXPR)))
{
tree newconst
= fold (build (MINUS_EXPR, TREE_TYPE (varop),
constop, TREE_OPERAND (varop, 1)));
/* Do not overwrite the current varop to be a predecrement,
create a new node so that we won't confuse our caller who
might create trees and throw them away, reusing the
arguments that they passed to build. This shows up in
the THEN or ELSE parts of ?: being postdecrements. */
varop = build (PREDECREMENT_EXPR, TREE_TYPE (varop),
TREE_OPERAND (varop, 0),
TREE_OPERAND (varop, 1));
if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF
&& DECL_BIT_FIELD(TREE_OPERAND
(TREE_OPERAND (varop, 0), 1)))
{
int size
= TREE_INT_CST_LOW (DECL_SIZE
(TREE_OPERAND
(TREE_OPERAND (varop, 0), 1)));
tree mask, unsigned_type;
unsigned int precision;
tree folded_compare;
if (constopnum == 0)
folded_compare = fold (build (code, type, constop,
TREE_OPERAND (varop, 0)));
else
folded_compare = fold (build (code, type,
TREE_OPERAND (varop, 0),
constop));
if (integer_zerop (folded_compare)
|| integer_onep (folded_compare))
return omit_one_operand (type, folded_compare, varop);
unsigned_type = type_for_size (size, 1);
precision = TYPE_PRECISION (unsigned_type);
mask = build_int_2 (~0, ~0);
TREE_TYPE (mask) = TREE_TYPE (varop);
force_fit_type (mask, 0);
mask = const_binop (RSHIFT_EXPR, mask,
size_int (precision - size), 0);
newconst = fold (build (BIT_AND_EXPR,
TREE_TYPE (varop), newconst,
convert (TREE_TYPE (varop),
mask)));
}
t = build (code, type,
(constopnum == 0) ? newconst : varop,
(constopnum == 1) ? newconst : varop);
return t;
}
}
}
/* Change X >= CST to X > (CST - 1) if CST is positive. */
if (TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg0) != INTEGER_CST
&& tree_int_cst_sgn (arg1) > 0)
{
switch (TREE_CODE (t))
{
case GE_EXPR:
code = GT_EXPR;
arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
t = build (code, type, TREE_OPERAND (t, 0), arg1);
break;
case LT_EXPR:
code = LE_EXPR;
arg1 = const_binop (MINUS_EXPR, arg1, integer_one_node, 0);
t = build (code, type, TREE_OPERAND (t, 0), arg1);
break;
default:
break;
}
}
/* If this is an EQ or NE comparison of a constant with a PLUS_EXPR or
a MINUS_EXPR of a constant, we can convert it into a comparison with
a revised constant as long as no overflow occurs. */
if ((code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (arg1) == INTEGER_CST
&& (TREE_CODE (arg0) == PLUS_EXPR
|| TREE_CODE (arg0) == MINUS_EXPR)
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
&& 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
? MINUS_EXPR : PLUS_EXPR,
arg1, TREE_OPERAND (arg0, 1), 0))
&& ! TREE_CONSTANT_OVERFLOW (tem))
return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
/* Similarly for a NEGATE_EXPR. */
else if ((code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (arg0) == NEGATE_EXPR
&& TREE_CODE (arg1) == INTEGER_CST
&& 0 != (tem = negate_expr (arg1))
&& TREE_CODE (tem) == INTEGER_CST
&& ! TREE_CONSTANT_OVERFLOW (tem))
return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));
/* If we have X - Y == 0, we can convert that to X == Y and similarly
for !=. Don't do this for ordered comparisons due to overflow. */
else if ((code == NE_EXPR || code == EQ_EXPR)
&& integer_zerop (arg1) && TREE_CODE (arg0) == MINUS_EXPR)
return fold (build (code, type,
TREE_OPERAND (arg0, 0), TREE_OPERAND (arg0, 1)));
/* If we are widening one operand of an integer comparison,
see if the other operand is similarly being widened. Perhaps we
can do the comparison in the narrower type. */
else if (TREE_CODE (TREE_TYPE (arg0)) == INTEGER_TYPE
&& TREE_CODE (arg0) == NOP_EXPR
&& (tem = get_unwidened (arg0, NULL_TREE)) != arg0
&& (t1 = get_unwidened (arg1, TREE_TYPE (tem))) != 0
&& (TREE_TYPE (t1) == TREE_TYPE (tem)
|| (TREE_CODE (t1) == INTEGER_CST
&& int_fits_type_p (t1, TREE_TYPE (tem)))))
return fold (build (code, type, tem, convert (TREE_TYPE (tem), t1)));
/* If this is comparing a constant with a MIN_EXPR or a MAX_EXPR of a
constant, we can simplify it. */
else if (TREE_CODE (arg1) == INTEGER_CST
&& (TREE_CODE (arg0) == MIN_EXPR
|| TREE_CODE (arg0) == MAX_EXPR)
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST)
return optimize_minmax_comparison (t);
/* If we are comparing an ABS_EXPR with a constant, we can
convert all the cases into explicit comparisons, but they may
well not be faster than doing the ABS and one comparison.
But ABS (X) <= C is a range comparison, which becomes a subtraction
and a comparison, and is probably faster. */
else if (code == LE_EXPR && TREE_CODE (arg1) == INTEGER_CST
&& TREE_CODE (arg0) == ABS_EXPR
&& ! TREE_SIDE_EFFECTS (arg0)
&& (0 != (tem = negate_expr (arg1)))
&& TREE_CODE (tem) == INTEGER_CST
&& ! TREE_CONSTANT_OVERFLOW (tem))
return fold (build (TRUTH_ANDIF_EXPR, type,
build (GE_EXPR, type, TREE_OPERAND (arg0, 0), tem),
build (LE_EXPR, type,
TREE_OPERAND (arg0, 0), arg1)));
/* If this is an EQ or NE comparison with zero and ARG0 is
(1 << foo) & bar, convert it to (bar >> foo) & 1. Both require
two operations, but the latter can be done in one less insn
on machines that have only two-operand insns or on which a
constant cannot be the first operand. */
if (integer_zerop (arg1) && (code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (arg0) == BIT_AND_EXPR)
{
if (TREE_CODE (TREE_OPERAND (arg0, 0)) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 0), 0)))
return
fold (build (code, type,
build (BIT_AND_EXPR, TREE_TYPE (arg0),
build (RSHIFT_EXPR,
TREE_TYPE (TREE_OPERAND (arg0, 0)),
TREE_OPERAND (arg0, 1),
TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)),
convert (TREE_TYPE (arg0),
integer_one_node)),
arg1));
else if (TREE_CODE (TREE_OPERAND (arg0, 1)) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg0, 1), 0)))
return
fold (build (code, type,
build (BIT_AND_EXPR, TREE_TYPE (arg0),
build (RSHIFT_EXPR,
TREE_TYPE (TREE_OPERAND (arg0, 1)),
TREE_OPERAND (arg0, 0),
TREE_OPERAND (TREE_OPERAND (arg0, 1), 1)),
convert (TREE_TYPE (arg0),
integer_one_node)),
arg1));
}
/* If this is an NE or EQ comparison of zero against the result of a
signed MOD operation whose second operand is a power of 2, make
the MOD operation unsigned since it is simpler and equivalent. */
if ((code == NE_EXPR || code == EQ_EXPR)
&& integer_zerop (arg1)
&& ! TREE_UNSIGNED (TREE_TYPE (arg0))
&& (TREE_CODE (arg0) == TRUNC_MOD_EXPR
|| TREE_CODE (arg0) == CEIL_MOD_EXPR
|| TREE_CODE (arg0) == FLOOR_MOD_EXPR
|| TREE_CODE (arg0) == ROUND_MOD_EXPR)
&& integer_pow2p (TREE_OPERAND (arg0, 1)))
{
tree newtype = unsigned_type (TREE_TYPE (arg0));
tree newmod = build (TREE_CODE (arg0), newtype,
convert (newtype, TREE_OPERAND (arg0, 0)),
convert (newtype, TREE_OPERAND (arg0, 1)));
return build (code, type, newmod, convert (newtype, arg1));
}
/* If this is an NE comparison of zero with an AND of one, remove the
comparison since the AND will give the correct value. */
if (code == NE_EXPR && integer_zerop (arg1)
&& TREE_CODE (arg0) == BIT_AND_EXPR
&& integer_onep (TREE_OPERAND (arg0, 1)))
return convert (type, arg0);
/* If we have (A & C) == C where C is a power of 2, convert this into
(A & C) != 0. Similarly for NE_EXPR. */
if ((code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (arg0) == BIT_AND_EXPR
&& integer_pow2p (TREE_OPERAND (arg0, 1))
&& operand_equal_p (TREE_OPERAND (arg0, 1), arg1, 0))
return build (code == EQ_EXPR ? NE_EXPR : EQ_EXPR, type,
arg0, integer_zero_node);
/* If X is unsigned, convert X < (1 << Y) into X >> Y == 0
and similarly for >= into !=. */
if ((code == LT_EXPR || code == GE_EXPR)
&& TREE_UNSIGNED (TREE_TYPE (arg0))
&& TREE_CODE (arg1) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (arg1, 0)))
return build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
TREE_OPERAND (arg1, 1)),
convert (TREE_TYPE (arg0), integer_zero_node));
else if ((code == LT_EXPR || code == GE_EXPR)
&& TREE_UNSIGNED (TREE_TYPE (arg0))
&& (TREE_CODE (arg1) == NOP_EXPR
|| TREE_CODE (arg1) == CONVERT_EXPR)
&& TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR
&& integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0)))
return
build (code == LT_EXPR ? EQ_EXPR : NE_EXPR, type,
convert (TREE_TYPE (arg0),
build (RSHIFT_EXPR, TREE_TYPE (arg0), arg0,
TREE_OPERAND (TREE_OPERAND (arg1, 0), 1))),
convert (TREE_TYPE (arg0), integer_zero_node));
/* Simplify comparison of something with itself. (For IEEE
floating-point, we can only do some of these simplifications.) */
if (operand_equal_p (arg0, arg1, 0))
{
switch (code)
{
case EQ_EXPR:
case GE_EXPR:
case LE_EXPR:
if (! FLOAT_TYPE_P (TREE_TYPE (arg0)))
return constant_boolean_node (1, type);
code = EQ_EXPR;
TREE_SET_CODE (t, code);
break;
case NE_EXPR:
/* For NE, we can only do this simplification if integer. */
if (FLOAT_TYPE_P (TREE_TYPE (arg0)))
break;
/* ... fall through ... */
case GT_EXPR:
case LT_EXPR:
return constant_boolean_node (0, type);
default:
abort ();
}
}
/* An unsigned comparison against 0 can be simplified. */
if (integer_zerop (arg1)
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
|| POINTER_TYPE_P (TREE_TYPE (arg1)))
&& TREE_UNSIGNED (TREE_TYPE (arg1)))
{
switch (TREE_CODE (t))
{
case GT_EXPR:
code = NE_EXPR;
TREE_SET_CODE (t, NE_EXPR);
break;
case LE_EXPR:
code = EQ_EXPR;
TREE_SET_CODE (t, EQ_EXPR);
break;
case GE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
case LT_EXPR:
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
default:
break;
}
}
/* Comparisons with the highest or lowest possible integer of
the specified size will have known values and an unsigned
<= 0x7fffffff can be simplified. */
{
int width = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (arg1)));
if (TREE_CODE (arg1) == INTEGER_CST
&& ! TREE_CONSTANT_OVERFLOW (arg1)
&& width <= HOST_BITS_PER_WIDE_INT
&& (INTEGRAL_TYPE_P (TREE_TYPE (arg1))
|| POINTER_TYPE_P (TREE_TYPE (arg1))))
{
if (TREE_INT_CST_HIGH (arg1) == 0
&& (TREE_INT_CST_LOW (arg1)
== ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1)
&& ! TREE_UNSIGNED (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
case GT_EXPR:
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
case GE_EXPR:
TREE_SET_CODE (t, EQ_EXPR);
break;
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
case LT_EXPR:
TREE_SET_CODE (t, NE_EXPR);
break;
default:
break;
}
else if (TREE_INT_CST_HIGH (arg1) == -1
&& (TREE_INT_CST_LOW (arg1)
== ((unsigned HOST_WIDE_INT) 1 << (width - 1)))
&& ! TREE_UNSIGNED (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
case LT_EXPR:
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
case LE_EXPR:
TREE_SET_CODE (t, EQ_EXPR);
break;
case GE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
case GT_EXPR:
TREE_SET_CODE (t, NE_EXPR);
break;
default:
break;
}
else if (TREE_INT_CST_HIGH (arg1) == 0
&& (TREE_INT_CST_LOW (arg1)
== ((unsigned HOST_WIDE_INT) 1 << (width - 1)) - 1)
&& TREE_UNSIGNED (TREE_TYPE (arg1))
/* signed_type does not work on pointer types. */
&& INTEGRAL_TYPE_P (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
case LE_EXPR:
return fold (build (GE_EXPR, type,
convert (signed_type (TREE_TYPE (arg0)),
arg0),
convert (signed_type (TREE_TYPE (arg1)),
integer_zero_node)));
case GT_EXPR:
return fold (build (LT_EXPR, type,
convert (signed_type (TREE_TYPE (arg0)),
arg0),
convert (signed_type (TREE_TYPE (arg1)),
integer_zero_node)));
default:
break;
}
else if (TREE_INT_CST_HIGH (arg1) == 0
&& (TREE_INT_CST_LOW (arg1)
== ((unsigned HOST_WIDE_INT) 2 << (width - 1)) - 1)
&& TREE_UNSIGNED (TREE_TYPE (arg1)))
switch (TREE_CODE (t))
{
case GT_EXPR:
return omit_one_operand (type,
convert (type, integer_zero_node),
arg0);
case GE_EXPR:
TREE_SET_CODE (t, EQ_EXPR);
break;
case LE_EXPR:
return omit_one_operand (type,
convert (type, integer_one_node),
arg0);
case LT_EXPR:
TREE_SET_CODE (t, NE_EXPR);
break;
default:
break;
}
}
}
/* If we are comparing an expression that just has comparisons
of two integer values, arithmetic expressions of those comparisons,
and constants, we can simplify it. There are only three cases
to check: the two values can either be equal, the first can be
greater, or the second can be greater. Fold the expression for
those three values. Since each value must be 0 or 1, we have
eight possibilities, each of which corresponds to the constant 0
or 1 or one of the six possible comparisons.
This handles common cases like (a > b) == 0 but also handles
expressions like ((x > y) - (y > x)) > 0, which supposedly
occur in macroized code. */
if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg0) != INTEGER_CST)
{
tree cval1 = 0, cval2 = 0;
int save_p = 0;
if (twoval_comparison_p (arg0, &cval1, &cval2, &save_p)
/* Don't handle degenerate cases here; they should already
have been handled anyway. */
&& cval1 != 0 && cval2 != 0
&& ! (TREE_CONSTANT (cval1) && TREE_CONSTANT (cval2))
&& TREE_TYPE (cval1) == TREE_TYPE (cval2)
&& INTEGRAL_TYPE_P (TREE_TYPE (cval1))
&& TYPE_MAX_VALUE (TREE_TYPE (cval1))
&& TYPE_MAX_VALUE (TREE_TYPE (cval2))
&& ! operand_equal_p (TYPE_MIN_VALUE (TREE_TYPE (cval1)),
TYPE_MAX_VALUE (TREE_TYPE (cval2)), 0))
{
tree maxval = TYPE_MAX_VALUE (TREE_TYPE (cval1));
tree minval = TYPE_MIN_VALUE (TREE_TYPE (cval1));
/* We can't just pass T to eval_subst in case cval1 or cval2
was the same as ARG1. */
tree high_result
= fold (build (code, type,
eval_subst (arg0, cval1, maxval, cval2, minval),
arg1));
tree equal_result
= fold (build (code, type,
eval_subst (arg0, cval1, maxval, cval2, maxval),
arg1));
tree low_result
= fold (build (code, type,
eval_subst (arg0, cval1, minval, cval2, maxval),
arg1));
/* All three of these results should be 0 or 1. Confirm they
are. Then use those values to select the proper code
to use. */
if ((integer_zerop (high_result)
|| integer_onep (high_result))
&& (integer_zerop (equal_result)
|| integer_onep (equal_result))
&& (integer_zerop (low_result)
|| integer_onep (low_result)))
{
/* Make a 3-bit mask with the high-order bit being the
value for `>', the next for '=', and the low for '<'. */
switch ((integer_onep (high_result) * 4)
+ (integer_onep (equal_result) * 2)
+ integer_onep (low_result))
{
case 0:
/* Always false. */
return omit_one_operand (type, integer_zero_node, arg0);
case 1:
code = LT_EXPR;
break;
case 2:
code = EQ_EXPR;
break;
case 3:
code = LE_EXPR;
break;
case 4:
code = GT_EXPR;
break;
case 5:
code = NE_EXPR;
break;
case 6:
code = GE_EXPR;
break;
case 7:
/* Always true. */
return omit_one_operand (type, integer_one_node, arg0);
}
t = build (code, type, cval1, cval2);
if (save_p)
return save_expr (t);
else
return fold (t);
}
}
}
/* If this is a comparison of a field, we may be able to simplify it. */
if ((TREE_CODE (arg0) == COMPONENT_REF
|| TREE_CODE (arg0) == BIT_FIELD_REF)
&& (code == EQ_EXPR || code == NE_EXPR)
/* Handle the constant case even without -O
to make sure the warnings are given. */
&& (optimize || TREE_CODE (arg1) == INTEGER_CST))
{
t1 = optimize_bit_field_compare (code, type, arg0, arg1);
return t1 ? t1 : t;
}
/* If this is a comparison of complex values and either or both sides
are a COMPLEX_EXPR or COMPLEX_CST, it is best to split up the
comparisons and join them with a TRUTH_ANDIF_EXPR or TRUTH_ORIF_EXPR.
This may prevent needless evaluations. */
if ((code == EQ_EXPR || code == NE_EXPR)
&& TREE_CODE (TREE_TYPE (arg0)) == COMPLEX_TYPE
&& (TREE_CODE (arg0) == COMPLEX_EXPR
|| TREE_CODE (arg1) == COMPLEX_EXPR
|| TREE_CODE (arg0) == COMPLEX_CST
|| TREE_CODE (arg1) == COMPLEX_CST))
{
tree subtype = TREE_TYPE (TREE_TYPE (arg0));
tree real0, imag0, real1, imag1;
arg0 = save_expr (arg0);
arg1 = save_expr (arg1);
real0 = fold (build1 (REALPART_EXPR, subtype, arg0));
imag0 = fold (build1 (IMAGPART_EXPR, subtype, arg0));
real1 = fold (build1 (REALPART_EXPR, subtype, arg1));
imag1 = fold (build1 (IMAGPART_EXPR, subtype, arg1));
return fold (build ((code == EQ_EXPR ? TRUTH_ANDIF_EXPR
: TRUTH_ORIF_EXPR),
type,
fold (build (code, type, real0, real1)),
fold (build (code, type, imag0, imag1))));
}
/* Optimize comparisons of strlen vs zero to a compare of the
first character of the string vs zero. To wit,
strlen(ptr) == 0 => *ptr == 0
strlen(ptr) != 0 => *ptr != 0
Other cases should reduce to one of these two (or a constant)
due to the return value of strlen being unsigned. */
if ((code == EQ_EXPR || code == NE_EXPR)
&& integer_zerop (arg1)
&& TREE_CODE (arg0) == CALL_EXPR
&& TREE_CODE (TREE_OPERAND (arg0, 0)) == ADDR_EXPR)
{
tree fndecl = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
tree arglist;
if (TREE_CODE (fndecl) == FUNCTION_DECL
&& DECL_BUILT_IN (fndecl)
&& DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_MD
&& DECL_FUNCTION_CODE (fndecl) == BUILT_IN_STRLEN
&& (arglist = TREE_OPERAND (arg0, 1))
&& TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) == POINTER_TYPE
&& ! TREE_CHAIN (arglist))
return fold (build (code, type,
build1 (INDIRECT_REF, char_type_node,
TREE_VALUE(arglist)),
integer_zero_node));
}
/* From here on, the only cases we handle are when the result is
known to be a constant.
To compute GT, swap the arguments and do LT.
To compute GE, do LT and invert the result.
To compute LE, swap the arguments, do LT and invert the result.
To compute NE, do EQ and invert the result.
Therefore, the code below must handle only EQ and LT. */
if (code == LE_EXPR || code == GT_EXPR)
{
tem = arg0, arg0 = arg1, arg1 = tem;
code = swap_tree_comparison (code);
}
/* Note that it is safe to invert for real values here because we
will check below in the one case that it matters. */
t1 = NULL_TREE;
invert = 0;
if (code == NE_EXPR || code == GE_EXPR)
{
invert = 1;
code = invert_tree_comparison (code);
}
/* Compute a result for LT or EQ if args permit;
otherwise return T. */
if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST)
{
if (code == EQ_EXPR)
t1 = build_int_2 (tree_int_cst_equal (arg0, arg1), 0);
else
t1 = build_int_2 ((TREE_UNSIGNED (TREE_TYPE (arg0))
? INT_CST_LT_UNSIGNED (arg0, arg1)
: INT_CST_LT (arg0, arg1)),
0);
}
#if 0 /* This is no longer useful, but breaks some real code. */
/* Assume a nonexplicit constant cannot equal an explicit one,
since such code would be undefined anyway.
Exception: on sysvr4, using #pragma weak,
a label can come out as 0. */
else if (TREE_CODE (arg1) == INTEGER_CST
&& !integer_zerop (arg1)
&& TREE_CONSTANT (arg0)
&& TREE_CODE (arg0) == ADDR_EXPR
&& code == EQ_EXPR)
t1 = build_int_2 (0, 0);
#endif
/* Two real constants can be compared explicitly. */
else if (TREE_CODE (arg0) == REAL_CST && TREE_CODE (arg1) == REAL_CST)
{
/* If either operand is a NaN, the result is false with two
exceptions: First, an NE_EXPR is true on NaNs, but that case
is already handled correctly since we will be inverting the
result for NE_EXPR. Second, if we had inverted a LE_EXPR
or a GE_EXPR into a LT_EXPR, we must return true so that it
will be inverted into false. */
if (REAL_VALUE_ISNAN (TREE_REAL_CST (arg0))
|| REAL_VALUE_ISNAN (TREE_REAL_CST (arg1)))
t1 = build_int_2 (invert && code == LT_EXPR, 0);
else if (code == EQ_EXPR)
t1 = build_int_2 (REAL_VALUES_EQUAL (TREE_REAL_CST (arg0),
TREE_REAL_CST (arg1)),
0);
else
t1 = build_int_2 (REAL_VALUES_LESS (TREE_REAL_CST (arg0),
TREE_REAL_CST (arg1)),
0);
}
if (t1 == NULL_TREE)
return t;
if (invert)
TREE_INT_CST_LOW (t1) ^= 1;
TREE_TYPE (t1) = type;
if (TREE_CODE (type) == BOOLEAN_TYPE)
return truthvalue_conversion (t1);
return t1;
case COND_EXPR:
/* Pedantic ANSI C says that a conditional expression is never an lvalue,
so all simple results must be passed through pedantic_non_lvalue. */
if (TREE_CODE (arg0) == INTEGER_CST)
return pedantic_non_lvalue
(TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
return pedantic_omit_one_operand (type, arg1, arg0);
/* If the second operand is zero, invert the comparison and swap
the second and third operands. Likewise if the second operand
is constant and the third is not or if the third operand is
equivalent to the first operand of the comparison. */
if (integer_zerop (arg1)
|| (TREE_CONSTANT (arg1) && ! TREE_CONSTANT (TREE_OPERAND (t, 2)))
|| (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
&& operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
TREE_OPERAND (t, 2),
TREE_OPERAND (arg0, 1))))
{
/* See if this can be inverted. If it can't, possibly because
it was a floating-point inequality comparison, don't do
anything. */
tem = invert_truthvalue (arg0);
if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
{
t = build (code, type, tem,
TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
arg0 = tem;
/* arg1 should be the first argument of the new T. */
arg1 = TREE_OPERAND (t, 1);
STRIP_NOPS (arg1);
}
}
/* If we have A op B ? A : C, we may be able to convert this to a
simpler expression, depending on the operation and the values
of B and C. IEEE floating point prevents this though,
because A or B might be -0.0 or a NaN. */
if (TREE_CODE_CLASS (TREE_CODE (arg0)) == '<'
&& (TARGET_FLOAT_FORMAT != IEEE_FLOAT_FORMAT
|| ! FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
|| flag_unsafe_math_optimizations)
&& operand_equal_for_comparison_p (TREE_OPERAND (arg0, 0),
arg1, TREE_OPERAND (arg0, 1)))
{
tree arg2 = TREE_OPERAND (t, 2);
enum tree_code comp_code = TREE_CODE (arg0);
STRIP_NOPS (arg2);
/* If we have A op 0 ? A : -A, this is A, -A, abs (A), or abs (-A),
depending on the comparison operation. */
if ((FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 1)))
? real_zerop (TREE_OPERAND (arg0, 1))
: integer_zerop (TREE_OPERAND (arg0, 1)))
&& TREE_CODE (arg2) == NEGATE_EXPR
&& operand_equal_p (TREE_OPERAND (arg2, 0), arg1, 0))
switch (comp_code)
{
case EQ_EXPR:
return
pedantic_non_lvalue
(convert (type,
negate_expr
(convert (TREE_TYPE (TREE_OPERAND (t, 1)),
arg1))));
case NE_EXPR:
return pedantic_non_lvalue (convert (type, arg1));
case GE_EXPR:
case GT_EXPR:
if (TREE_UNSIGNED (TREE_TYPE (arg1)))
arg1 = convert (signed_type (TREE_TYPE (arg1)), arg1);
return pedantic_non_lvalue
(convert (type, fold (build1 (ABS_EXPR,
TREE_TYPE (arg1), arg1))));
case LE_EXPR:
case LT_EXPR:
if (TREE_UNSIGNED (TREE_TYPE (arg1)))
arg1 = convert (signed_type (TREE_TYPE (arg1)), arg1);
return pedantic_non_lvalue
(negate_expr (convert (type,
fold (build1 (ABS_EXPR,
TREE_TYPE (arg1),
arg1)))));
default:
abort ();
}
/* If this is A != 0 ? A : 0, this is simply A. For ==, it is
always zero. */
if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
{
if (comp_code == NE_EXPR)
return pedantic_non_lvalue (convert (type, arg1));
else if (comp_code == EQ_EXPR)
return pedantic_non_lvalue (convert (type, integer_zero_node));
}
/* If this is A op B ? A : B, this is either A, B, min (A, B),
or max (A, B), depending on the operation. */
if (operand_equal_for_comparison_p (TREE_OPERAND (arg0, 1),
arg2, TREE_OPERAND (arg0, 0)))
{
tree comp_op0 = TREE_OPERAND (arg0, 0);
tree comp_op1 = TREE_OPERAND (arg0, 1);
tree comp_type = TREE_TYPE (comp_op0);
/* Avoid adding NOP_EXPRs in case this is an lvalue. */
if (TYPE_MAIN_VARIANT (comp_type) == TYPE_MAIN_VARIANT (type))
comp_type = type;
switch (comp_code)
{
case EQ_EXPR:
return pedantic_non_lvalue (convert (type, arg2));
case NE_EXPR:
return pedantic_non_lvalue (convert (type, arg1));
case LE_EXPR:
case LT_EXPR:
/* In C++ a ?: expression can be an lvalue, so put the
operand which will be used if they are equal first
so that we can convert this back to the
corresponding COND_EXPR. */
return pedantic_non_lvalue
(convert (type, fold (build (MIN_EXPR, comp_type,
(comp_code == LE_EXPR
? comp_op0 : comp_op1),
(comp_code == LE_EXPR
? comp_op1 : comp_op0)))));
break;
case GE_EXPR:
case GT_EXPR:
return pedantic_non_lvalue
(convert (type, fold (build (MAX_EXPR, comp_type,
(comp_code == GE_EXPR
? comp_op0 : comp_op1),
(comp_code == GE_EXPR
? comp_op1 : comp_op0)))));
break;
default:
abort ();
}
}
/* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
we might still be able to simplify this. For example,
if C1 is one less or one more than C2, this might have started
out as a MIN or MAX and been transformed by this function.
Only good for INTEGER_TYPEs, because we need TYPE_MAX_VALUE. */
if (INTEGRAL_TYPE_P (type)
&& TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST
&& TREE_CODE (arg2) == INTEGER_CST)
switch (comp_code)
{
case EQ_EXPR:
/* We can replace A with C1 in this case. */
arg1 = convert (type, TREE_OPERAND (arg0, 1));
t = build (code, type, TREE_OPERAND (t, 0), arg1,
TREE_OPERAND (t, 2));
break;
case LT_EXPR:
/* If C1 is C2 + 1, this is min(A, C2). */
if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (PLUS_EXPR, arg2,
integer_one_node, 0), 1))
return pedantic_non_lvalue
(fold (build (MIN_EXPR, type, arg1, arg2)));
break;
case LE_EXPR:
/* If C1 is C2 - 1, this is min(A, C2). */
if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (MINUS_EXPR, arg2,
integer_one_node, 0), 1))
return pedantic_non_lvalue
(fold (build (MIN_EXPR, type, arg1, arg2)));
break;
case GT_EXPR:
/* If C1 is C2 - 1, this is max(A, C2). */
if (! operand_equal_p (arg2, TYPE_MIN_VALUE (type), 1)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (MINUS_EXPR, arg2,
integer_one_node, 0), 1))
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
break;
case GE_EXPR:
/* If C1 is C2 + 1, this is max(A, C2). */
if (! operand_equal_p (arg2, TYPE_MAX_VALUE (type), 1)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (PLUS_EXPR, arg2,
integer_one_node, 0), 1))
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
break;
case NE_EXPR:
break;
default:
abort ();
}
}
/* If the second operand is simpler than the third, swap them
since that produces better jump optimization results. */
if ((TREE_CONSTANT (arg1) || DECL_P (arg1)
|| TREE_CODE (arg1) == SAVE_EXPR)
&& ! (TREE_CONSTANT (TREE_OPERAND (t, 2))
|| DECL_P (TREE_OPERAND (t, 2))
|| TREE_CODE (TREE_OPERAND (t, 2)) == SAVE_EXPR))
{
/* See if this can be inverted. If it can't, possibly because
it was a floating-point inequality comparison, don't do
anything. */
tem = invert_truthvalue (arg0);
if (TREE_CODE (tem) != TRUTH_NOT_EXPR)
{
t = build (code, type, tem,
TREE_OPERAND (t, 2), TREE_OPERAND (t, 1));
arg0 = tem;
/* arg1 should be the first argument of the new T. */
arg1 = TREE_OPERAND (t, 1);
STRIP_NOPS (arg1);
}
}
/* Convert A ? 1 : 0 to simply A. */
if (integer_onep (TREE_OPERAND (t, 1))
&& integer_zerop (TREE_OPERAND (t, 2))
/* If we try to convert TREE_OPERAND (t, 0) to our type, the
call to fold will try to move the conversion inside
a COND, which will recurse. In that case, the COND_EXPR
is probably the best choice, so leave it alone. */
&& type == TREE_TYPE (arg0))
return pedantic_non_lvalue (arg0);
/* Look for expressions of the form A & 2 ? 2 : 0. The result of this
operation is simply A & 2. */
if (integer_zerop (TREE_OPERAND (t, 2))
&& TREE_CODE (arg0) == NE_EXPR
&& integer_zerop (TREE_OPERAND (arg0, 1))
&& integer_pow2p (arg1)
&& TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
&& operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
arg1, 1))
return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
return t;
case COMPOUND_EXPR:
/* When pedantic, a compound expression can be neither an lvalue
nor an integer constant expression. */
if (TREE_SIDE_EFFECTS (arg0) || pedantic)
return t;
/* Don't let (0, 0) be null pointer constant. */
if (integer_zerop (arg1))
return build1 (NOP_EXPR, type, arg1);
return convert (type, arg1);
case COMPLEX_EXPR:
if (wins)
return build_complex (type, arg0, arg1);
return t;
case REALPART_EXPR:
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
return t;
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
return omit_one_operand (type, TREE_OPERAND (arg0, 0),
TREE_OPERAND (arg0, 1));
else if (TREE_CODE (arg0) == COMPLEX_CST)
return TREE_REALPART (arg0);
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
return fold (build (TREE_CODE (arg0), type,
fold (build1 (REALPART_EXPR, type,
TREE_OPERAND (arg0, 0))),
fold (build1 (REALPART_EXPR,
type, TREE_OPERAND (arg0, 1)))));
return t;
case IMAGPART_EXPR:
if (TREE_CODE (TREE_TYPE (arg0)) != COMPLEX_TYPE)
return convert (type, integer_zero_node);
else if (TREE_CODE (arg0) == COMPLEX_EXPR)
return omit_one_operand (type, TREE_OPERAND (arg0, 1),
TREE_OPERAND (arg0, 0));
else if (TREE_CODE (arg0) == COMPLEX_CST)
return TREE_IMAGPART (arg0);
else if (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR)
return fold (build (TREE_CODE (arg0), type,
fold (build1 (IMAGPART_EXPR, type,
TREE_OPERAND (arg0, 0))),
fold (build1 (IMAGPART_EXPR, type,
TREE_OPERAND (arg0, 1)))));
return t;
/* Pull arithmetic ops out of the CLEANUP_POINT_EXPR where
appropriate. */
case CLEANUP_POINT_EXPR:
if (! has_cleanups (arg0))
return TREE_OPERAND (t, 0);
{
enum tree_code code0 = TREE_CODE (arg0);
int kind0 = TREE_CODE_CLASS (code0);
tree arg00 = TREE_OPERAND (arg0, 0);
tree arg01;
if (kind0 == '1' || code0 == TRUTH_NOT_EXPR)
return fold (build1 (code0, type,
fold (build1 (CLEANUP_POINT_EXPR,
TREE_TYPE (arg00), arg00))));
if (kind0 == '<' || kind0 == '2'
|| code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR
|| code0 == TRUTH_AND_EXPR || code0 == TRUTH_OR_EXPR
|| code0 == TRUTH_XOR_EXPR)
{
arg01 = TREE_OPERAND (arg0, 1);
if (TREE_CONSTANT (arg00)
|| ((code0 == TRUTH_ANDIF_EXPR || code0 == TRUTH_ORIF_EXPR)
&& ! has_cleanups (arg00)))
return fold (build (code0, type, arg00,
fold (build1 (CLEANUP_POINT_EXPR,
TREE_TYPE (arg01), arg01))));
if (TREE_CONSTANT (arg01))
return fold (build (code0, type,
fold (build1 (CLEANUP_POINT_EXPR,
TREE_TYPE (arg00), arg00)),
arg01));
}
return t;
}
case CALL_EXPR:
/* Check for a built-in function. */
if (TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR
&& (TREE_CODE (TREE_OPERAND (TREE_OPERAND (expr, 0), 0))
== FUNCTION_DECL)
&& DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (expr, 0), 0)))
{
tree tmp = fold_builtin (expr);
if (tmp)
return tmp;
}
return t;
default:
return t;
} /* switch (code) */
}
/* Determine if first argument is a multiple of second argument. Return 0 if
it is not, or we cannot easily determined it to be.
An example of the sort of thing we care about (at this point; this routine
could surely be made more general, and expanded to do what the *_DIV_EXPR's
fold cases do now) is discovering that
SAVE_EXPR (I) * SAVE_EXPR (J * 8)
is a multiple of
SAVE_EXPR (J * 8)
when we know that the two SAVE_EXPR (J * 8) nodes are the same node.
This code also handles discovering that
SAVE_EXPR (I) * SAVE_EXPR (J * 8)
is a multiple of 8 so we don't have to worry about dealing with a
possible remainder.
Note that we *look* inside a SAVE_EXPR only to determine how it was
calculated; it is not safe for fold to do much of anything else with the
internals of a SAVE_EXPR, since it cannot know when it will be evaluated
at run time. For example, the latter example above *cannot* be implemented
as SAVE_EXPR (I) * J or any variant thereof, since the value of J at
evaluation time of the original SAVE_EXPR is not necessarily the same at
the time the new expression is evaluated. The only optimization of this
sort that would be valid is changing
SAVE_EXPR (I) * SAVE_EXPR (SAVE_EXPR (J) * 8)
divided by 8 to
SAVE_EXPR (I) * SAVE_EXPR (J)
(where the same SAVE_EXPR (J) is used in the original and the
transformed version). */
static int
multiple_of_p (type, top, bottom)
tree type;
tree top;
tree bottom;
{
if (operand_equal_p (top, bottom, 0))
return 1;
if (TREE_CODE (type) != INTEGER_TYPE)
return 0;
switch (TREE_CODE (top))
{
case MULT_EXPR:
return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
|| multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
case PLUS_EXPR:
case MINUS_EXPR:
return (multiple_of_p (type, TREE_OPERAND (top, 0), bottom)
&& multiple_of_p (type, TREE_OPERAND (top, 1), bottom));
case LSHIFT_EXPR:
if (TREE_CODE (TREE_OPERAND (top, 1)) == INTEGER_CST)
{
tree op1, t1;
op1 = TREE_OPERAND (top, 1);
/* const_binop may not detect overflow correctly,
so check for it explicitly here. */
if (TYPE_PRECISION (TREE_TYPE (size_one_node))
> TREE_INT_CST_LOW (op1)
&& TREE_INT_CST_HIGH (op1) == 0
&& 0 != (t1 = convert (type,
const_binop (LSHIFT_EXPR, size_one_node,
op1, 0)))
&& ! TREE_OVERFLOW (t1))
return multiple_of_p (type, t1, bottom);
}
return 0;
case NOP_EXPR:
/* Can't handle conversions from non-integral or wider integral type. */
if ((TREE_CODE (TREE_TYPE (TREE_OPERAND (top, 0))) != INTEGER_TYPE)
|| (TYPE_PRECISION (type)
< TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (top, 0)))))
return 0;
/* .. fall through ... */
case SAVE_EXPR:
return multiple_of_p (type, TREE_OPERAND (top, 0), bottom);
case INTEGER_CST:
if (TREE_CODE (bottom) != INTEGER_CST
|| (TREE_UNSIGNED (type)
&& (tree_int_cst_sgn (top) < 0
|| tree_int_cst_sgn (bottom) < 0)))
return 0;
return integer_zerop (const_binop (TRUNC_MOD_EXPR,
top, bottom, 0));
default:
return 0;
}
}
/* Return true if `t' is known to be non-negative. */
int
tree_expr_nonnegative_p (t)
tree t;
{
switch (TREE_CODE (t))
{
case ABS_EXPR:
case FFS_EXPR:
return 1;
case INTEGER_CST:
return tree_int_cst_sgn (t) >= 0;
case TRUNC_DIV_EXPR:
case CEIL_DIV_EXPR:
case FLOOR_DIV_EXPR:
case ROUND_DIV_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case TRUNC_MOD_EXPR:
case CEIL_MOD_EXPR:
case FLOOR_MOD_EXPR:
case ROUND_MOD_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
case COND_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 1))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 2));
case COMPOUND_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case MIN_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
&& tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case MAX_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0))
|| tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case MODIFY_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case BIND_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 1));
case SAVE_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
case NON_LVALUE_EXPR:
return tree_expr_nonnegative_p (TREE_OPERAND (t, 0));
case RTL_EXPR:
return rtl_expr_nonnegative_p (RTL_EXPR_RTL (t));
default:
if (truth_value_p (TREE_CODE (t)))
/* Truth values evaluate to 0 or 1, which is nonnegative. */
return 1;
else
/* We don't know sign of `t', so be conservative and return false. */
return 0;
}
}
/* Return true if `r' is known to be non-negative.
Only handles constants at the moment. */
int
rtl_expr_nonnegative_p (r)
rtx r;
{
switch (GET_CODE (r))
{
case CONST_INT:
return INTVAL (r) >= 0;
case CONST_DOUBLE:
if (GET_MODE (r) == VOIDmode)
return CONST_DOUBLE_HIGH (r) >= 0;
return 0;
case SYMBOL_REF:
case LABEL_REF:
/* These are always nonnegative. */
return 1;
default:
return 0;
}
}
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