put the idx arguments of simd_insert and simd_extract into const blocks #1530
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RalfJung force-pushed the simd-extrac-insert-const-idx branch 5 times, most recently from d1013a2 to a2f32c8 Compare 
| ☔ The latest upstream changes (presumably 4d9c0bb) made this pull request unmergeable. Please resolve the merge conflicts. |
RalfJung force-pushed the simd-extrac-insert-const-idx branch from 1c42b00 to b754cf2 Compare 
RalfJung commented Feb 17, 2024
| /// Use for testing only. | ||
| // FIXME: Workaround rust@60637 | ||
| #[inline(always)] | ||
| pub(crate) fn extract(self, index: usize) -> $ety { |
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FWIW the function should have been unsafe since it performed unchecked indexing.
I made it safe by adding an assert.
bors added a commit to rust-lang-ci/rust that referenced this pull request Feb 22, 2024
…dx, r=oli-obk,Amanieu require simd_insert, simd_extract indices to be constants As discussed in rust-lang#77477 (see in particular [here](rust-lang#77477 (comment))). This PR doesn't touch codegen yet -- the first step is to ensure that the indices are always constants; the second step is to then make use of this fact in backends. Blocked on rust-lang/stdarch#1530 propagating to the rustc repo.
bors added a commit to rust-lang/miri that referenced this pull request Feb 25, 2024
…-obk,Amanieu require simd_insert, simd_extract indices to be constants As discussed in rust-lang/rust#77477 (see in particular [here](rust-lang/rust#77477 (comment))). This PR doesn't touch codegen yet -- the first step is to ensure that the indices are always constants; the second step is to then make use of this fact in backends. Blocked on rust-lang/stdarch#1530 propagating to the rustc repo.
lnicola pushed a commit to lnicola/rust-analyzer that referenced this pull request Apr 7, 2024
…-obk,Amanieu require simd_insert, simd_extract indices to be constants As discussed in rust-lang/rust#77477 (see in particular [here](rust-lang/rust#77477 (comment))). This PR doesn't touch codegen yet -- the first step is to ensure that the indices are always constants; the second step is to then make use of this fact in backends. Blocked on rust-lang/stdarch#1530 propagating to the rustc repo.
RalfJung pushed a commit to RalfJung/rust-analyzer that referenced this pull request Apr 27, 2024
…-obk,Amanieu require simd_insert, simd_extract indices to be constants As discussed in rust-lang/rust#77477 (see in particular [here](rust-lang/rust#77477 (comment))). This PR doesn't touch codegen yet -- the first step is to ensure that the indices are always constants; the second step is to then make use of this fact in backends. Blocked on rust-lang/stdarch#1530 propagating to the rustc repo.
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In rust-lang/rust#77477 the general consensus seems to be that these arguments should always be consts. So I have a patch for rustc that enforces them to be const. This is the stdarch side of this, adding const-blocks everywhere to ensure these arguments are const. I decided to follow the same pattern as simd_shuffle and add a macro that adds the const block.
However, there's one use of non-constant indices that can't be easily ported to use inline const blocks: the
extractmethod on SIMD types, which is used (at least) by PowerPC tests. Also see here.