Merged
Conversation
As proposed in WebAssembly/simd#379. Since this instruction is still being evaluated for inclusion in the SIMD proposal, this PR does not add support for it to the C/JS APIs or to the fuzzer. This PR also performs a drive-by fix for unrelated instructions in c-api-kitchen-sink.c
aheejin
approved these changes
Oct 27, 2020
| return unary<16, &Literal::getLanesUI8x16, &Literal::neg>(*this); | ||
| } | ||
| Literal Literal::popcntI8x16() const { | ||
| return unary<16, &Literal::getLanesUI8x16, &Literal::popCount>(*this); |
Member
There was a problem hiding this comment.
Is each lane signed or unsigned? The LLVM builtin says it's signed though
Member
Author
There was a problem hiding this comment.
Signedness doesn't really make a difference for popcnt since it doesn't interpret the bits as a number. However, it's important to use the unsigned lane extraction function here because it will zero-extend each lane. If we instead used the signed lane extraction function, it would sign-extend each lane which could change the population counts.
kripken
approved these changes
Oct 27, 2020
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
As proposed in WebAssembly/simd#379. Since this
instruction is still being evaluated for inclusion in the SIMD proposal, this PR
does not add support for it to the C/JS APIs or to the fuzzer. This PR also
performs a drive-by fix for unrelated instructions in c-api-kitchen-sink.c