From 93d60d0de76e5dca666682e51589c0819eed2507 Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly0@users.noreply.github.com>
Date: Mon, 31 Oct 2022 21:40:39 -0400
Subject: [PATCH] std: avoid vector usage with the C backend

Vectors are not yet implemented in the C backend, so no reason to
prevent code using the standard library from compiling in the meantime.
---
 lib/std/crypto/blake3.zig    |  5 ++++-
 lib/std/crypto/gimli.zig     |  2 +-
 lib/std/multi_array_list.zig | 12 +++++++++---
 lib/std/target.zig           | 13 +++++++++++--
 4 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/lib/std/crypto/blake3.zig b/lib/std/crypto/blake3.zig
index 762ec67f31..4f8d023532 100644
--- a/lib/std/crypto/blake3.zig
+++ b/lib/std/crypto/blake3.zig
@@ -200,7 +200,10 @@ const CompressGeneric = struct {
     }
 };
 
-const compress = if (builtin.cpu.arch == .x86_64) CompressVectorized.compress else CompressGeneric.compress;
+const compress = if (builtin.cpu.arch == .x86_64 and builtin.zig_backend != .stage2_c)
+    CompressVectorized.compress
+else
+    CompressGeneric.compress;
 
 fn first8Words(words: [16]u32) [8]u32 {
     return @ptrCast(*const [8]u32, &words).*;
diff --git a/lib/std/crypto/gimli.zig b/lib/std/crypto/gimli.zig
index 96a7d69e6f..4952937697 100644
--- a/lib/std/crypto/gimli.zig
+++ b/lib/std/crypto/gimli.zig
@@ -152,7 +152,7 @@ pub const State = struct {
         self.endianSwap();
     }
 
-    pub const permute = if (builtin.cpu.arch == .x86_64) impl: {
+    pub const permute = if (builtin.cpu.arch == .x86_64 and builtin.zig_backend != .stage2_c) impl: {
         break :impl permute_vectorized;
     } else if (builtin.mode == .ReleaseSmall) impl: {
         break :impl permute_small;
diff --git a/lib/std/multi_array_list.zig b/lib/std/multi_array_list.zig
index c3bfa6537b..89c7869b6b 100644
--- a/lib/std/multi_array_list.zig
+++ b/lib/std/multi_array_list.zig
@@ -436,9 +436,15 @@ pub fn MultiArrayList(comptime S: type) type {
         }
 
         fn capacityInBytes(capacity: usize) usize {
-            const sizes_vector: @Vector(sizes.bytes.len, usize) = sizes.bytes;
-            const capacity_vector = @splat(sizes.bytes.len, capacity);
-            return @reduce(.Add, capacity_vector * sizes_vector);
+            if (builtin.zig_backend == .stage2_c) {
+                var bytes: usize = 0;
+                for (sizes.bytes) |size| bytes += size * capacity;
+                return bytes;
+            } else {
+                const sizes_vector: @Vector(sizes.bytes.len, usize) = sizes.bytes;
+                const capacity_vector = @splat(sizes.bytes.len, capacity);
+                return @reduce(.Add, capacity_vector * sizes_vector);
+            }
         }
 
         fn allocatedBytes(self: Self) []align(@alignOf(S)) u8 {
diff --git a/lib/std/target.zig b/lib/std/target.zig
index 342e535c27..34bae7cda2 100644
--- a/lib/std/target.zig
+++ b/lib/std/target.zig
@@ -1,4 +1,5 @@
 const std = @import("std.zig");
+const builtin = @import("builtin");
 const mem = std.mem;
 const Version = std.builtin.Version;
 
@@ -719,7 +720,11 @@ pub const Target = struct {
 
                 /// Adds the specified feature set but not its dependencies.
                 pub fn addFeatureSet(set: *Set, other_set: Set) void {
-                    set.ints = @as(@Vector(usize_count, usize), set.ints) | @as(@Vector(usize_count, usize), other_set.ints);
+                    if (builtin.zig_backend == .stage2_c) {
+                        for (set.ints) |*int, i| int.* |= other_set.ints[i];
+                    } else {
+                        set.ints = @as(@Vector(usize_count, usize), set.ints) | @as(@Vector(usize_count, usize), other_set.ints);
+                    }
                 }
 
                 /// Removes the specified feature but not its dependents.
@@ -731,7 +736,11 @@ pub const Target = struct {
 
                 /// Removes the specified feature but not its dependents.
                 pub fn removeFeatureSet(set: *Set, other_set: Set) void {
-                    set.ints = @as(@Vector(usize_count, usize), set.ints) & ~@as(@Vector(usize_count, usize), other_set.ints);
+                    if (builtin.zig_backend == .stage2_c) {
+                        for (set.ints) |*int, i| int.* &= ~other_set.ints[i];
+                    } else {
+                        set.ints = @as(@Vector(usize_count, usize), set.ints) & ~@as(@Vector(usize_count, usize), other_set.ints);
+                    }
                 }
 
                 pub fn populateDependencies(set: *Set, all_features_list: []const Cpu.Feature) void {