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rust/tests/ui/simd
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Matthias Krüger 3a69035338
Rollup merge of #151346 - folkertdev:simd-splat, r=workingjubilee 
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:

- https://github.com/rust-lang/rust/issues/60637
- https://github.com/rust-lang/rust/issues/137407
- https://github.com/rust-lang/rust/issues/122623
- https://github.com/rust-lang/rust/issues/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.
2026-01-24 21:04:15 +01:00
..
auxiliary Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
intrinsic Rollup merge of #151346 - folkertdev:simd-splat, r=workingjubilee 2026-01-24 21:04:15 +01:00
array-trait.rs remove most simd_ intrinsic declaration in tests 2025-02-27 12:22:59 +01:00
array-trait.stderr Unconditionally run check_item_type on all items 2025-06-30 08:06:08 +00:00
array-type.rs remove most simd_ intrinsic declaration in tests 2025-02-27 12:22:59 +01:00
const-err-trumps-simd-err.rs stabilize gai 2025-06-11 15:30:15 +01:00
const-err-trumps-simd-err.stderr Revert "Rollup merge of #122661 - estebank:assert-macro-span, r=petrochenkov" 2025-09-11 09:10:46 +08:00
dont-invalid-bitcast-masks.rs test: dont optimize to invalid bitcasts 2024-06-24 16:54:18 -07:00
dont-invalid-bitcast-x86_64.rs test: dont optimize to invalid bitcasts 2024-06-24 16:54:18 -07:00
empty-simd-vector-in-operand.rs UI tests: add missing diagnostic kinds where possible 2025-04-08 23:06:31 +03:00
empty-simd-vector-in-operand.stderr fix: running the test only on x86_64. 2025-03-23 19:42:14 +01:00
extern-static-zero-length.rs Fix ICE when using zero-length SIMD type in extern static 2026-01-22 21:16:34 +03:00
extern-static-zero-length.stderr Fix ICE when using zero-length SIMD type in extern static 2026-01-22 21:16:34 +03:00
generics.rs So many test updates x_x 2025-07-20 10:15:14 -07:00
issue-17170.rs Add ignore-backends annotations in failing GCC backend ui tests 2025-07-23 13:48:04 +02:00
issue-32947.rs run some tests on emscripten again 2025-02-24 19:48:24 +01:00
issue-39720.rs Add ignore-backends annotations in failing GCC backend ui tests 2025-07-23 13:48:04 +02:00
issue-85915-simd-ptrs.rs So many test updates x_x 2025-07-20 10:15:14 -07:00
issue-89193.rs So many test updates x_x 2025-07-20 10:15:14 -07:00
issue-105439.rs Ban projecting into SIMD types [MCP838] 2025-07-20 10:22:09 -07:00
libm_no_std_cant_float.rs Update std::simd usage and test outputs 2023-11-26 09:02:25 -05:00
libm_no_std_cant_float.stderr Use tcx.short_string() in more diagnostics 2025-08-07 21:18:00 +00:00
libm_std_can_float.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00
masked-load-store-build-fail.rs Add alignment parameter to simd_masked_{load,store} 2025-11-04 02:30:59 +05:30
masked-load-store-build-fail.stderr Add alignment parameter to simd_masked_{load,store} 2025-11-04 02:30:59 +05:30
masked-load-store-check-fail.rs Add alignment parameter to simd_masked_{load,store} 2025-11-04 02:30:59 +05:30
masked-load-store-check-fail.stderr Add alignment parameter to simd_masked_{load,store} 2025-11-04 02:30:59 +05:30
masked-load-store.rs Enable const-testing for the ported SIMD intrinsics 2025-11-17 20:10:14 +05:30
monomorphize-heterogeneous.rs Ban non-array SIMD 2024-09-09 19:39:43 -07:00
monomorphize-heterogeneous.stderr Ban non-array SIMD 2024-09-09 19:39:43 -07:00
monomorphize-shuffle-index.generic.stderr Ignore more failing ui tests for GCC backend 2025-09-26 15:33:48 +02:00
monomorphize-shuffle-index.rs Ignore more failing ui tests for GCC backend 2025-09-26 15:33:48 +02:00
monomorphize-too-long.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
monomorphize-too-long.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
monomorphize-zero-length.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
monomorphize-zero-length.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
not-out-of-bounds.rs Ignore more failing ui tests for GCC backend 2025-09-26 15:33:48 +02:00
not-out-of-bounds.stderr test: Subtract code_offset from width for ui_testing 2025-10-02 05:45:16 -06:00
portable-intrinsics-arent-exposed.rs Gate 2015 UI tests 2025-11-27 11:19:00 -05:00
portable-intrinsics-arent-exposed.stderr Gate 2015 UI tests 2025-11-27 11:19:00 -05:00
repr-simd-on-enum.rs MIR-build: No longer emit assumes in enum-as casting 2025-07-24 10:18:37 -07:00
repr-simd-on-enum.stderr MIR-build: No longer emit assumes in enum-as casting 2025-07-24 10:18:37 -07:00
repr_packed.rs Add ignore-backends annotations in failing GCC backend ui tests 2025-07-23 13:48:04 +02:00
shuffle.rs So many test updates x_x 2025-07-20 10:15:14 -07:00
simd-bitmask-notpow2.rs Enable const-testing for the ported SIMD intrinsics 2025-11-17 20:10:14 +05:30
simd-bitmask.rs Enable const-testing for the ported SIMD intrinsics 2025-11-17 20:10:14 +05:30
simd-lane-limit-err-npow2.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
simd-lane-limit-err-npow2.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
simd-lane-limit-err.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
simd-lane-limit-err.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
simd-lane-limit-ok.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
size-align.rs intrinsics: rename min_align_of to align_of 2025-06-12 17:50:25 +02:00
target-feature-mixup.rs Ignore more failing ui tests in GCC backend 2025-10-13 15:20:49 +02:00
type-generic-monomorphisation-empty.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
type-generic-monomorphisation-empty.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
type-generic-monomorphisation-extern-nonnull-ptr.rs Update tests. 2025-01-07 16:04:14 +01:00
type-generic-monomorphisation-non-primitive.rs compiletest: Require //~ annotations even if error-pattern is specified 2025-04-03 11:08:55 +03:00
type-generic-monomorphisation-non-primitive.stderr Show number in error message even for one error 2023-11-24 19:15:52 +01:00
type-generic-monomorphisation-oversized.rs Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
type-generic-monomorphisation-oversized.stderr Add an attribute to check the number of lanes in a SIMD vector after monomorphization 2025-09-23 20:47:34 -04:00
type-generic-monomorphisation-power-of-two.rs fix use of platform_intrinsics in tests 2024-02-25 08:15:44 +01:00
type-generic-monomorphisation-wide-ptr.rs compiletest: Require //~ annotations even if error-pattern is specified 2025-04-03 11:08:55 +03:00
type-generic-monomorphisation-wide-ptr.stderr Ban non-array SIMD 2024-09-09 19:39:43 -07:00
type-generic-monomorphisation.rs compiletest: Require //~ annotations even if error-pattern is specified 2025-04-03 11:08:55 +03:00
type-generic-monomorphisation.stderr Show number in error message even for one error 2023-11-24 19:15:52 +01:00
type-len.rs Ban non-array SIMD 2024-09-09 19:39:43 -07:00
type-len.stderr Ban non-array SIMD 2024-09-09 19:39:43 -07:00
type-wide-ptr.rs compiletest: Require //~ annotations even if error-pattern is specified 2025-04-03 11:08:55 +03:00
type-wide-ptr.stderr Show number in error message even for one error 2023-11-24 19:15:52 +01:00
wasm-simd-indirect.rs [AUTO-GENERATED] Migrate ui tests from // to //@ directives 2024-02-16 20:02:50 +00:00