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stage1: make @truncate to an integer type of different sign an error at comptime too

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This commit is contained in:
Matthew Borkowski 2021-05-28 23:32:19 -04:00 committed by Veikka Tuominen
parent ff0a15bb7a
commit 9ac6d28614
3 changed files with 53 additions and 17 deletions
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22
src/stage1/ir.cpp
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@ -19563,6 +19563,18 @@ static IrInstGen *ir_analyze_instruction_truncate(IrAnalyze *ira, IrInstSrcTrunc
return ir_implicit_cast2(ira, &instruction->target->base, target, dest_type);
}
if (src_type->id != ZigTypeIdComptimeInt) {
if (src_type->data.integral.is_signed != dest_type->data.integral.is_signed) {
const char *sign_str = dest_type->data.integral.is_signed ? "signed" : "unsigned";
ir_add_error(ira, &target->base, buf_sprintf("expected %s integer type, found '%s'", sign_str, buf_ptr(&src_type->name)));
return ira->codegen->invalid_inst_gen;
} else if (src_type->data.integral.bit_count > 0 && src_type->data.integral.bit_count < dest_type->data.integral.bit_count) {
ir_add_error(ira, &target->base, buf_sprintf("type '%s' has fewer bits than destination type '%s'",
buf_ptr(&src_type->name), buf_ptr(&dest_type->name)));
return ira->codegen->invalid_inst_gen;
}
}
if (instr_is_comptime(target)) {
ZigValue *val = ir_resolve_const(ira, target, UndefBad);
if (val == nullptr)
@ -19580,16 +19592,6 @@ static IrInstGen *ir_analyze_instruction_truncate(IrAnalyze *ira, IrInstSrcTrunc
return result;
}
if (src_type->data.integral.is_signed != dest_type->data.integral.is_signed) {
const char *sign_str = dest_type->data.integral.is_signed ? "signed" : "unsigned";
ir_add_error(ira, &target->base, buf_sprintf("expected %s integer type, found '%s'", sign_str, buf_ptr(&src_type->name)));
return ira->codegen->invalid_inst_gen;
} else if (src_type->data.integral.bit_count < dest_type->data.integral.bit_count) {
ir_add_error(ira, &target->base, buf_sprintf("type '%s' has fewer bits than destination type '%s'",
buf_ptr(&src_type->name), buf_ptr(&dest_type->name)));
return ira->codegen->invalid_inst_gen;
}
return ir_build_truncate_gen(ira, &instruction->base.base, dest_type, target);
}

29
test/behavior/truncate.zig
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@ -24,13 +24,34 @@ test "truncate.u0.var" {
try expect(z == 0);
}
test "truncate sign mismatch but comptime known so it works anyway" {
const x: u32 = 10;
var result = @truncate(i8, x);
try expect(result == 10);
test "truncate i0 to larger integer allowed and has comptime known result" {
var x: i0 = 0;
const y = @truncate(i8, x);
comptime try expect(y == 0);
}
test "truncate.i0.literal" {
var z = @truncate(i0, 0);
try expect(z == 0);
}
test "truncate.i0.const" {
const c0: isize = 0;
var z = @truncate(i0, c0);
try expect(z == 0);
}
test "truncate.i0.var" {
var d: i8 = 2;
var z = @truncate(i0, d);
try expect(z == 0);
}
test "truncate on comptime integer" {
var x = @truncate(u16, 9999);
try expect(x == 9999);
var y = @truncate(u16, -21555);
try expect(y == 0xabcd);
var z = @truncate(i16, -65537);
try expect(z == -1);
}

19
test/compile_errors.zig
View File

@ -6031,14 +6031,27 @@ pub fn addCases(cases: *tests.CompileErrorContext) void {
});
cases.add("truncate sign mismatch",
\\fn f() i8 {
\\export fn entry1() i8 {
\\ var x: u32 = 10;
\\ return @truncate(i8, x);
\\}
\\
\\export fn entry() usize { return @sizeOf(@TypeOf(f)); }
\\export fn entry2() u8 {
\\ var x: i32 = -10;
\\ return @truncate(u8, x);
\\}
\\export fn entry3() i8 {
\\ comptime var x: u32 = 10;
\\ return @truncate(i8, x);
\\}
\\export fn entry4() u8 {
\\ comptime var x: i32 = -10;
\\ return @truncate(u8, x);
\\}
, &[_][]const u8{
"tmp.zig:3:26: error: expected signed integer type, found 'u32'",
"tmp.zig:7:26: error: expected unsigned integer type, found 'i32'",
"tmp.zig:11:26: error: expected signed integer type, found 'u32'",
"tmp.zig:15:26: error: expected unsigned integer type, found 'i32'",
});
cases.add("try in function with non error return type",