[PATCH] D86371: [CodeGenPrepare][X86] Teach optimizeGatherScatterInst to turn a splat pointer into GEP with scalar base and 0 index

Tue Sep 1 09:32:45 PDT 2020

craig.topper added a comment.

In D86371#2249125 <https://reviews.llvm.org/D86371#2249125>, @RKSimon wrote:

> In D86371#2247925 <https://reviews.llvm.org/D86371#2247925>, @efriedma wrote:
>
>> If the address is a splat, generating a gather/scatter seems a little weird.  I guess if the mask is non-trivial, there isn't any obvious way to rewrite it in target-independent IR. though.
>
> Do we have any constant mask test cases?

No, but I don't think it really matters for this transform. If the mask is constant and the pointer is a splat, we should probably replace the gather/scatter with scalar load/store and shuffle/extractelement in instcombine.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D86371/new/

https://reviews.llvm.org/D86371