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std.simd: change T to u16

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The `element_bit_size` would break if `T` was signed due to `ceilPowerOfTwo` only working on unsigned numbers.
This commit is contained in:
Dan Ellis Echavarria 2022-09-07 07:22:30 -05:00 committed by GitHub
parent e02b9f458d
commit 924679abc4
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1 changed files with 10 additions and 1 deletions
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lib/std/simd.zig
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@ -9,7 +9,7 @@ const builtin = @import("builtin");
pub fn suggestVectorSizeForCpu(comptime T: type, comptime cpu: std.Target.Cpu) ?usize {
// This is guesswork, if you have better suggestions can add it or edit the current here
// This can run in comptime only, but stage 1 fails at it, stage 2 can understand it
const element_bit_size = @maximum(8, std.math.ceilPowerOfTwo(T, @bitSizeOf(T)) catch unreachable);
const element_bit_size = @maximum(8, std.math.ceilPowerOfTwo(u16, @bitSizeOf(T)) catch unreachable);
const vector_bit_size: u16 = blk: {
if (cpu.arch.isX86()) {
if (T == bool and std.Target.x86.featureSetHas(.prefer_mask_registers)) return 64;
@ -57,6 +57,15 @@ pub fn suggestVectorSize(comptime T: type) ?usize {
return suggestVectorSizeForCpu(T, builtin.cpu);
}
test "suggestVectorSizeForCpu works with signed and unsigned values" {
comptime var cpu = std.Target.Cpu.baseline(std.Target.Cpu.Arch.x86_64);
comptime cpu.features.addFeature(@enumToInt(std.Target.x86.Feature.avx512f));
const signed_integer_size = suggestVectorSizeForCpu(i32, cpu).?;
const unsigned_integer_size = suggestVectorSizeForCpu(u32, cpu).?;
try std.testing.expectEqual(@as(usize, 16), unsigned_integer_size);
try std.testing.expectEqual(@as(usize, 16), signed_integer_size);
}
fn vectorLength(comptime VectorType: type) comptime_int {
return switch (@typeInfo(VectorType)) {
.Vector => |info| info.len,