Rollup of 2 pull requests - #151584
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Hexagon assembler uses `.string` directive instead of `.asciz` for
null-terminated strings. Both are equivalent but the test was only
checking for `.asciz`.
Update the CHECK patterns to accept both directives using
`.{{asciz|string}}` regex pattern.
…bilee
add `simd_splat` intrinsic
Add `simd_splat` which lowers to the LLVM canonical splat sequence.
```llvm
insertelement <N x elem> poison, elem %x, i32 0
shufflevector <N x elem> v0, <N x elem> poison, <N x i32> zeroinitializer
```
Right now we try to fake it using one of
```rust
fn splat(x: u32) -> u32x8 {
u32x8::from_array([x; 8])
}
```
or (in `stdarch`)
```rust
fn splat(value: $elem_type) -> $name {
#[derive(Copy, Clone)]
#[repr(simd)]
struct JustOne([$elem_type; 1]);
let one = JustOne([value]);
// SAFETY: 0 is always in-bounds because we're shuffling
// a simd type with exactly one element.
unsafe { simd_shuffle!(one, one, [0; $len]) }
}
```
Both of these can confuse the LLVM optimizer, producing sub-par code. Some examples:
- rust-lang#60637
- rust-lang#137407
- rust-lang#122623
- rust-lang#97804
---
As far as I can tell there is no way to provide a fallback implementation for this intrinsic, because there is no `const` way of evaluating the number of elements (there might be issues beyond that, too). So, I added implementations for all 4 backends.
Both GCC and const-eval appear to have some issues with simd vectors containing pointers. I have a workaround for GCC, but haven't yet been able to make const-eval work. See the comments below.
Currently this just adds the intrinsic, it does not actually use it anywhere yet.
…ss35
Fix cstring-merging test for Hexagon target
Hexagon assembler uses `.string` directive instead of `.asciz` for null-terminated strings. Both are equivalent but the test was only checking for `.asciz`.
Update the CHECK patterns to accept both directives using `.{{asciz|string}}` regex pattern.
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Successful merges:
simd_splatintrinsic #151346 (addsimd_splatintrinsic)r? @ghost
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