[PATCH] D91059: [LoopVectorizer] NFCI: Calculate register usage based on TLI.getTypeLegalizationCost.

[Mikael Holmén via Phabricator via llvm-commits]

uabelho added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:5805
+  auto GetRegUsage = [&DL, &TTI=TTI](Type *Ty, ElementCount VF) {
     if (Ty->isTokenTy())
       return 0U;
----------------
sdesmalen wrote:
> The example provided by @uabelho fails for the load instruction (with a struct as result type) which is outside the loop body and isn't actually vectorized, so counting it as a vector register usage seems overly conservative. The `extractvalue` instruction in the body itself is vectorized, which is fine, since the extracted value  from the aggregate is a valid element type for a vector.
> 
> I suggest addressing the issue with:
> ```
> -  if (Ty->isTokenTy())
> +  if (Ty->isTokenTy() || !VectorType::isValidElementType(Ty))
>       return 0U;
> ```
> 
> @uabelho @SjoerdMeijer are you happy with me re-landing the patch with the above change?
I've verified that the above change fixes the problem and in the limited testing I've done of it I haven't seen any new problems. Thanks!

@SjoerdMeijer ?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D91059/new/

https://reviews.llvm.org/D91059