56 lines
1.6 KiB
Rust
56 lines
1.6 KiB
Rust
// compile-flags: -C opt-level=3 --edition=2021
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// only-x86_64
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// ignore-debug: the debug assertions get in the way
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#![crate_type = "lib"]
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#![feature(portable_simd)]
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use std::simd::{Simd, SimdUint};
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const N: usize = 8;
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#[no_mangle]
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// CHECK-LABEL: @wider_reduce_simd
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pub fn wider_reduce_simd(x: Simd<u8, N>) -> u16 {
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// CHECK: zext <8 x i8>
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// CHECK-SAME: to <8 x i16>
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// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
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let x: Simd<u16, N> = x.cast();
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x.reduce_sum()
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}
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#[no_mangle]
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// CHECK-LABEL: @wider_reduce_loop
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pub fn wider_reduce_loop(x: Simd<u8, N>) -> u16 {
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// CHECK: zext <8 x i8>
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// CHECK-SAME: to <8 x i16>
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// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
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let mut sum = 0_u16;
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for i in 0..N {
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sum += u16::from(x[i]);
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}
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sum
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}
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#[no_mangle]
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// CHECK-LABEL: @wider_reduce_iter
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pub fn wider_reduce_iter(x: Simd<u8, N>) -> u16 {
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// CHECK: zext <8 x i8>
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// CHECK-SAME: to <8 x i16>
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// CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
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x.as_array().iter().copied().map(u16::from).sum()
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}
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// This iterator one is the most interesting, as it's the one
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// which used to not auto-vectorize due to a suboptimality in the
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// `<array::IntoIter as Iterator>::fold` implementation.
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#[no_mangle]
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// CHECK-LABEL: @wider_reduce_into_iter
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pub fn wider_reduce_into_iter(x: Simd<u8, N>) -> u16 {
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// FIXME MIR inlining messes up LLVM optimizations.
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// WOULD-CHECK: zext <8 x i8>
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// WOULD-CHECK-SAME: to <8 x i16>
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// WOULD-CHECK: call i16 @llvm.vector.reduce.add.v8i16(<8 x i16>
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x.to_array().into_iter().map(u16::from).sum()
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}
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