Partially revert #868 #878
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This commit partially reverts rust-lang#868 to restore the intrinsics to their original implementation to avoid breaking changes. This is done while rust-lang/rust#73166 is running through crater, and should unblock rust-lang/rust#74482.
|
r? @gnzlbg (rust_highfive has picked a reviewer for you, use r? to override) |
|
r? @Amanieu |
jethrogb
pushed a commit
to jethrogb/stdsimd
that referenced
this pull request
Sep 8, 2020
This reverts commit 311d56c.
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Sep 15, 2020
Update stdarch
This PR **changes the public signature** of the following functions in `core::arch::{x86, x86_64}`:
```patch
-pub unsafe fn _mm256_extract_epi8(a: __m256i, imm8: i32) -> i8
+pub unsafe fn _mm256_extract_epi8(a: __m256i, imm8: i32) -> i32
-pub unsafe fn _mm256_extract_epi16(a: __m256i, imm8: i32) -> i16
+pub unsafe fn _mm256_extract_epi16(a: __m256i, imm8: i32) -> i32
```
This change is desired so that these signatures
* are similar to those of the 128-bit versions `_mm_extract_epi8` and `_mm_extract_epi16`
* match the Intel definitions for the intrinsics
* [RFC 2325](https://github.com/rust-lang/rfcs/blob/master/text/2325-stable-simd.md) specifies that the exact vendor function signatures should be used
A [crater run](rust-lang#73166 (comment)) revealed only a single breakage. The [vektor crate](https://github.com/AdamNiederer/vektor/blob/master/src/x86/avx2.rs#L2436-L2472) copied the incorrect signatures in `core` exactly to their own crate. The functions don't seem to be used by anyone anywhere.
Actual breakage is not expected, since due to the nature of the functions, users would generally write `_mm256_extract_epi8(...) as u8` or `_mm256_extract_epi16(...) as u16`.
See rust-lang/stdarch#868. Note that the changes from that stdarch PR have already partially landed in core after rust-lang/stdarch#878. This PR is now only about the remaining changes.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This commit partially reverts #868 to restore the intrinsics to their
original implementation to avoid breaking changes. This is done while
rust-lang/rust#73166 is running through crater, and should unblock
rust-lang/rust#74482.