rust-lang/portable-simd

View on GitHub

The testing ground for the future of portable SIMD in Rust

Stars: 1.1k
Forks: 108
Open beginner issues: 0
Indexed issues: 94
Avg merge: 22h 53m
Merged PRs (30d): 3

Dominant language: Rust
License: Apache-2.0
Last GitHub push: Sep 16, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: No code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

Open All

94 open issues indexed

Tests fail on latest nightly Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/portable-simd#546 · 2 comments · Opened Aug 7, 2026
`algebraic_*` on `f32x*`/`f64x*` Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 40/100

rust-lang/portable-simd#539 · Opened Jul 18, 2026
`PrivateMethods`' items aren't private, they are accessible via `MaskElement` Open

Difficulty 3/5 1-2 days Newbie friendliness 52/100

rust-lang/portable-simd#537 · 4 comments · Opened Jul 1, 2026
SimdPartialOrd methods for Mask don't match PartialOrd methods for bool Open

C-bug

Difficulty 3/5 1-2 days Newbie friendliness 54/100

rust-lang/portable-simd#527 · 3 comments · Opened May 10, 2026
Select is a strangely named trait and not part of the prelude Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#505 · 3 comments · Opened Feb 2, 2026
`StdFloat::round` incorrectly states ties round toward zero Open

C-bug

Difficulty 1/5 Under an hour Newbie friendliness 65/100

rust-lang/portable-simd#499 · Opened Jan 10, 2026
Excessive alignment constraints for larger than machine-sized vectors Open

C-feature-request

Difficulty 4/5 3-5 days Newbie friendliness 28/100

rust-lang/portable-simd#495 · Opened Dec 7, 2025
Improve `load`, `store`, `gather`, `scatter` codegen for targets without masked load/store instructions Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 42/100

rust-lang/portable-simd#494 · Opened Nov 29, 2025
swizzle_dyn: variant where out-of-bounds indices return implementation-defined result Open

C-feature-request

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/portable-simd#486 · Opened Oct 2, 2025
Add `unchecked_*` methods for integers Open

C-feature-request

Difficulty 3/5 1-2 days Newbie friendliness 42/100

rust-lang/portable-simd#481 · Opened Sep 10, 2025
Add `to_mask` function for `Simd` Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#479 · Opened Sep 5, 2025
`Simd::gather_unchecked()` Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 30/100

rust-lang/portable-simd#475 · 3 comments · Opened Aug 24, 2025
Mask operations are not optimized well Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 30/100

rust-lang/portable-simd#472 · 22 comments · Opened Aug 12, 2025
Constified SIMD Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#467 · 8 comments · Opened Jun 13, 2025
Test suite assumes that cos, exp, and other functions have deterministic precision Open

Difficulty 3/5 1-2 days Newbie friendliness 45/100

rust-lang/portable-simd#463 · 5 comments · Opened Jun 11, 2025
Better ergonomics for working with vector of pointers to structs/enums Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#459 · 1 comment · Opened Apr 21, 2025
Add `{u32,f32,...}xN` shorthand types for `Simd<{u32,f32,...}, N>` Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#447 · 3 comments · Opened Dec 23, 2024
Integer multiply high (mulh) equivalent in SimdInt and SimdUint Open

C-feature-request

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#440 · 3 comments · Opened Sep 18, 2024
Aligning std::simd and Rust on Arm v7 Neon float behavior Open

C-bug

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#439 · 15 comments · Opened Sep 12, 2024
`simd_div` and `simd_rem` ICEs for non-power-of-two length vectors on Aarch64 Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#427 · 4 comments · Opened Aug 8, 2024
why sub and mul operation of f32x4 is slower than scalar version? Open

Difficulty 4/5 3-5 days Newbie friendliness 25/100

rust-lang/portable-simd#426 · 4 comments · Opened Jun 22, 2024
Fast round Open

C-feature-request

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#421 · 3 comments · Opened May 21, 2024
Can't use generic_const_exprs Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#416 · 1 comment · Opened Apr 16, 2024
Seemless softwere/hardwere computation interoperation Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 20/100

rust-lang/portable-simd#403 · 1 comment · Opened Mar 7, 2024
Bit operations on float Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 38/100

rust-lang/portable-simd#388 · 8 comments · 2 reactions · Opened Feb 9, 2024
MulAdd and MulAddAssign Open

C-feature-request

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#387 · 9 comments · Opened Jan 5, 2024
API to specify max number of elements Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 30/100

rust-lang/portable-simd#373 · 13 comments · Opened Nov 15, 2023
Ensure `load`s of vector types have `!noundef` Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#372 · Opened Nov 12, 2023
Saturating casts for integers, like `_mm_packus_epi16` and `_mm_packs_epi16` Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 30/100

rust-lang/portable-simd#369 · 5 comments · Opened Oct 6, 2023
Support for `_mm_maddubs_epi16` and `_mm_maddubs_epi16` and similar? Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#366 · 3 comments · Opened Sep 24, 2023
Critical issues before stabilization Open

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#364 · 69 comments · 54 reactions · Opened Sep 10, 2023
Bounds check is not eliminated Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#356 · 5 comments · Opened Jul 10, 2023
ensure array/slice load/store functions actually optimize to LLVM IR vector `load`/`store` instructions Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#343 · Opened Apr 26, 2023
don't use `read_unaligned` to read from an array casted to `*const Simd` Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

rust-lang/portable-simd#341 · 5 comments · Opened Apr 23, 2023
Support avx512 bitmasks with dynamic feature detection Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/portable-simd#332 · 3 comments · 2 reactions · Opened Mar 7, 2023
gather with i32 indexes Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/portable-simd#329 · 11 comments · Opened Feb 4, 2023
Float to integer casts on x86 produce scalar instructions Open

A-LLVM C-bug I-scalarize

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#325 · 2 comments · Opened Jan 7, 2023
change gather/scatter mask sizes to match data size not index/address size since that matches x86_64 Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#323 · Opened Dec 14, 2022
Simd-using functions sometimes scalarize after inlining, even if they use vector ops on their own Open

I-scalarize

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#321 · 9 comments · Opened Dec 5, 2022
`wasm32-unknown-unknown` doesn't use simd instructions (at least, for one particular example, but plausibly more) Open

Difficulty 4/5 3-5 days Newbie friendliness 38/100

rust-lang/portable-simd#320 · 3 comments · Opened Dec 3, 2022
Transpose methods? Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#306 · 8 comments · Opened Oct 16, 2022
Bad codegen for bitwise OR/AND masks Open

I-scalarize I-slow

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#303 · 4 comments · Opened Sep 22, 2022
Poor performance on u64 and i64 Open

I-slow

Difficulty 4/5 3-5 days Newbie friendliness 25/100

rust-lang/portable-simd#297 · 5 comments · Opened Jul 28, 2022
`simd_swizzle` plays not well with type inference Open

C-bug

Difficulty 4/5 3-5 days Newbie friendliness 42/100

rust-lang/portable-simd#292 · 1 comment · 3 reactions · Opened Jul 13, 2022
LLVM error when using f64x8.scatter_select Open

A-LLVM C-bug

Difficulty 4/5 3-5 days Newbie friendliness 35/100

rust-lang/portable-simd#290 · 3 comments · Opened Jul 1, 2022
Support `MaybeUninit` vectors Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#286 · 9 comments · Opened Jun 16, 2022
Concat and split operations Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#277 · 4 comments · 1 reaction · Opened Apr 14, 2022
Convenience methods for range-check operations Open

C-feature-request

Difficulty 5/5 Over a week Newbie friendliness 35/100

rust-lang/portable-simd#275 · 6 comments · Opened Apr 11, 2022
mask8x8::from_bitmask falls back to scalar code Open

C-bug I-scalarize

Difficulty 4/5 3-5 days Newbie friendliness 42/100

rust-lang/portable-simd#264 · 7 comments · Opened Mar 13, 2022
Introduce "dynamic swizzling" into LLVMIR and Rust intrinsics Open

A-LLVM C-feature-request C-tracking-issue E-hard

Difficulty 5/5 Over a week Newbie friendliness 25/100

rust-lang/portable-simd#242 · 10 comments · 12 reactions · Opened Feb 6, 2022

rust-lang/portable-simd

Get new issues in your inbox