Port the remaining SIMD intrinsics to const-eval #147520

sayantn · 2025-10-09T11:43:38Z

successor to #146568, this refactors some implementations and ports the implementation of simd_fma and simd_relaxed_fmato rustc_const_eval

Also adds some remaining f16/f128 support in these intrinsics

r? @RalfJung

rustbot · 2025-10-09T11:43:42Z

Some changes occurred to the CTFE / Miri interpreter

cc @rust-lang/miri

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

sayantn · 2025-10-09T11:50:32Z

In a similar fashion to #146568, I have not made the signatures const. If this gets merged quickly enough, I will just add these to #147521, otherwise new PR it is

RalfJung

Thanks! Here are some first comments.

All of the new intrinsics Miri supports with this will also need Miri tests.

View changes since this review

compiler/rustc_const_eval/src/interpret/intrinsics/simd.rs

compiler/rustc_const_eval/src/interpret/intrinsics.rs

RalfJung · 2025-10-09T15:27:35Z

successor to #146568, this refactors some implementations and implements the following SIMD intrinsics in const-eval

Please update the PR description: This doesn't actually add anything in const-eval, it adds it to the interpreter and then only exposes this in Miri.

compiler/rustc_const_eval/src/interpret/intrinsics/simd.rs

RalfJung

Thanks!
Still missing tests for the new f16/f128 support.

View changes since this review

compiler/rustc_const_eval/src/interpret/intrinsics.rs

src/tools/miri/src/intrinsics/simd.rs

sayantn · 2025-10-10T16:38:44Z

Do we really need f16/f128 tests? It's painful to add them because portable_simd doesn't implement SimdElement for f16 and f128, so we have to roll our own repr_simd types

RalfJung · 2025-10-10T20:12:32Z

Why do we add f16/f128 support if portable_simd can't even use it?

tests/pass/intrinsics/portable-simd.rs already declares two custom repr(simd) types. That only takes a few lines of code. Declaring two more shouldn't be so bad. We only need smoke tests, but I'd rather not have entirely dead codepaths here.

sayantn · 2025-10-10T20:24:01Z

I am adding them mostly for completeness sake, but stdarch will need simd_fma with f16.

Declaring two more shouldn't be so bad.

Ok I will add 👍

sayantn · 2025-10-10T22:30:43Z

@rustbot ready

added tests for f16 and f128 (just copied f32 and f64 tests)

RalfJung · 2025-10-11T10:46:47Z

src/tools/miri/tests/pass/intrinsics/portable-simd.rs

 #[rustc_nounwind]
 pub unsafe fn simd_shuffle_const_generic<T, U, const IDX: &'static [u32]>(x: T, y: T) -> U;

+pub fn simd_ops_f16() {


Your new functions aren't actually being called, but you made them pub which suppresses the warning...

Oh sorry, my mistake

Please remove all these pub. I think we have enough evidence to consider them dangerous. :)

src/tools/miri/tests/pass/intrinsics/portable-simd.rs

RalfJung · 2025-10-11T12:22:47Z

@rustbot author

rustbot · 2025-10-11T12:22:51Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

bors · 2025-10-13T23:43:27Z

☔ The latest upstream changes (presumably #147640) made this pull request unmergeable. Please resolve the merge conflicts.

rustbot · 2025-10-26T17:10:43Z

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

sayantn · 2025-10-26T17:12:52Z

@rustbot ready

Sorry for the delay @RalfJung. Made sure the tests were actually being called. Had to remove simd_fsqrt tests for f16 and f128, as they are Miri-only and currently unimplemented for f16 and f128

compiler/rustc_const_eval/src/interpret/intrinsics/simd.rs

RalfJung

Just minor nits.

View changes since this review

compiler/rustc_const_eval/src/interpret/intrinsics.rs

RalfJung · 2025-11-03T16:11:22Z

Thanks!
@bors r+

bors · 2025-11-03T16:11:26Z

📌 Commit 0681bae has been approved by RalfJung

It is now in the queue for this repository.

Rollup of 8 pull requests Successful merges: - #135099 (Add FileCheck annotations to mir-opt/copy-prop) - #145903 (Give correct suggestion for a typo in raw pointers) - #147520 (Port the remaining SIMD intrinsics to const-eval) - #148068 (rustdoc: Use configured target modifiers when collecting doctests) - #148099 (Prepare to move debugger discovery from compiletest to bootstrap) - #148268 (rustdoc: fix `--emit=dep-info` on scraped examples) - #148306 (Remove double check when decoding ExpnId to avoid races) - #148378 (Fix documentation for std::panic::update_hook) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of #147520 - sayantn:simd-const-eval, r=RalfJung Port the remaining SIMD intrinsics to const-eval successor to #146568, this refactors some implementations and ports the implementation of `simd_fma` and `simd_relaxed_fma`to `rustc_const_eval` Also adds some remaining f16/f128 support in these intrinsics r? `@RalfJung`

Rollup of 8 pull requests Successful merges: - rust-lang/rust#135099 (Add FileCheck annotations to mir-opt/copy-prop) - rust-lang/rust#145903 (Give correct suggestion for a typo in raw pointers) - rust-lang/rust#147520 (Port the remaining SIMD intrinsics to const-eval) - rust-lang/rust#148068 (rustdoc: Use configured target modifiers when collecting doctests) - rust-lang/rust#148099 (Prepare to move debugger discovery from compiletest to bootstrap) - rust-lang/rust#148268 (rustdoc: fix `--emit=dep-info` on scraped examples) - rust-lang/rust#148306 (Remove double check when decoding ExpnId to avoid races) - rust-lang/rust#148378 (Fix documentation for std::panic::update_hook) r? `@ghost` `@rustbot` modify labels: rollup

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sayantn force-pushed the simd-const-eval branch from 344e3dc to b8a4c23 Compare October 9, 2025 11:59

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sayantn force-pushed the simd-const-eval branch from b8a4c23 to 69a2513 Compare October 9, 2025 17:53

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Implement SIMD funnel shifts in const-eval/Miri #147534

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sayantn changed the title ~~Implement the remaining SIMD intrinsics in const-eval~~ Port the remaining SIMD intrinsics to const-eval Oct 9, 2025

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sayantn force-pushed the simd-const-eval branch from 69a2513 to 7c594eb Compare October 10, 2025 16:39

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Implement simd_fma and simd_relaxed_fma in const-eval

c4d6b0b

sayantn force-pushed the simd-const-eval branch from 389bf9a to 25ab970 Compare October 26, 2025 17:10

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sayantn added 4 commits November 3, 2025 12:22

Refactor implementation of float minmax intrinsics

d335ea9

Refactor float rounding intrinsics a bit

ebf2e10

Add some missing f16-f128 support in intrinsics

4d70bf4

Add Miri tests for f16/f128 SIMD operations

0681bae

sayantn force-pushed the simd-const-eval branch from 25ab970 to 0681bae Compare November 3, 2025 06:53

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GuillaumeGomez mentioned this pull request Nov 3, 2025

Rollup of 8 pull requests #148446

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bors merged commit c8625a5 into rust-lang:master Nov 3, 2025
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sayantn mentioned this pull request Nov 5, 2025

Implement SimdElement for f16 rust-lang/portable-simd#487

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Port the remaining SIMD intrinsics to const-eval #147520

Port the remaining SIMD intrinsics to const-eval #147520

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