Skip to content

Commit

Permalink
Auto merge of #116018 - DianQK:simd-wide-sum-test, r=scottmcm
Browse files Browse the repository at this point in the history
Increasing the SIMD size improves the vectorization possibilities

Change the `simd-wide-sum.rs` to pass tests based on the LLVM main branch.

For smaller lengths, we cannot expect to always get vectorized.

A related discussion at https://rust-lang.zulipchat.com/#narrow/stream/187780-t-compiler.2Fwg-llvm/topic/LLVM.20HEAD.3A.20codegen.2Fsimd.2Fsimd-wide-sum.2Ers.20newly.20failing.

r? scottmcm
  • Loading branch information
bors committed Oct 6, 2023
2 parents ff05789 + e300847 commit d4ba2b4
Showing 1 changed file with 13 additions and 13 deletions.
26 changes: 13 additions & 13 deletions tests/codegen/simd/simd-wide-sum.rs
Original file line number Diff line number Diff line change
Expand Up @@ -11,24 +11,24 @@
#![feature(portable_simd)]

use std::simd::{Simd, SimdUint};
const N: usize = 8;
const N: usize = 16;

#[no_mangle]
// CHECK-LABEL: @wider_reduce_simd
pub fn wider_reduce_simd(x: Simd<u8, N>) -> u16 {
// CHECK: zext <8 x i8>
// CHECK-SAME: to <8 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
// CHECK: zext <16 x i8>
// CHECK-SAME: to <16 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
let x: Simd<u16, N> = x.cast();
x.reduce_sum()
}

#[no_mangle]
// CHECK-LABEL: @wider_reduce_loop
pub fn wider_reduce_loop(x: Simd<u8, N>) -> u16 {
// CHECK: zext <8 x i8>
// CHECK-SAME: to <8 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
// CHECK: zext <16 x i8>
// CHECK-SAME: to <16 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
let mut sum = 0_u16;
for i in 0..N {
sum += u16::from(x[i]);
Expand All @@ -39,9 +39,9 @@ pub fn wider_reduce_loop(x: Simd<u8, N>) -> u16 {
#[no_mangle]
// CHECK-LABEL: @wider_reduce_iter
pub fn wider_reduce_iter(x: Simd<u8, N>) -> u16 {
// CHECK: zext <8 x i8>
// CHECK-SAME: to <8 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
// CHECK: zext <16 x i8>
// CHECK-SAME: to <16 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v16i16(<16 x i16>
x.as_array().iter().copied().map(u16::from).sum()
}

Expand All @@ -52,8 +52,8 @@ pub fn wider_reduce_iter(x: Simd<u8, N>) -> u16 {
#[no_mangle]
// CHECK-LABEL: @wider_reduce_into_iter
pub fn wider_reduce_into_iter(x: Simd<u8, N>) -> u16 {
// CHECK: zext <8 x i8>
// CHECK-SAME: to <8 x i16>
// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
// FIXME: It would be nice if this was exactly the same as the above tests,
// but at the time of writing this comment, that didn't happen on LLVM main.
// CHECK: call i16 @llvm.vector.reduce.add
x.to_array().into_iter().map(u16::from).sum()
}

0 comments on commit d4ba2b4

Please sign in to comment.