[PATCH] D90445: [SLP] Make SLPVectorizer to use `llvm.masked.gather` intrinsic

Sat Oct 31 02:32:14 PDT 2020

RKSimon added a comment.

Please can you rebase after rG1eeae4310771d8a6896fe09effe88883998f34e8 <https://reviews.llvm.org/rG1eeae4310771d8a6896fe09effe88883998f34e8>?

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Comment at: llvm/test/Transforms/SLPVectorizer/X86/pr47629.ll:17
+; CHECK-NEXT:    store <4 x i32> [[TMP11]], <4 x i32>* [[TMP12]], align 4
 ; CHECK-NEXT:    ret void
 ;
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anton-afanasyev wrote:
> anton-afanasyev wrote:
> > RKSimon wrote:
> > > This doesn't look great in the final codegen: https://gcc.godbolt.org/z/vE9Yoe
> > > 
> > > Which suggests either the costs aren't correct or we're not correctly including the cost of something - the buildvector of the pointers? are we missing getelementptr vectorization?
> > Oops, thanks, it looks I've missed the buildvector cost.
> Hmm, investigated this: no, I was wrong, the calculated cost is correct (`insertelemets`s for gather instr are compesated by `insertelement`s for buildvector). Further investigating this... Looks like codegen issue more.
Hmm - does the X86 TTI handle buildvectors of pointers costs or does it fallback to the generic implementation (which is almost certainly lower)?

Repository:
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  https://reviews.llvm.org/D90445/new/

https://reviews.llvm.org/D90445