[PATCH] D140260: [LoopVectorize] Fix crash on "vector->scalar" bitcast vectorization

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D140260#4004038 <https://reviews.llvm.org/D140260#4004038>, @mdchen wrote:

> In D140260#4003727 <https://reviews.llvm.org/D140260#4003727>, @lebedev.ri wrote:
>
>> It think the loop-invariantness precondition for these is overly restrictive.
>
> Any suggestion on that?

For context. loading i64 and loading <8 x i8> and bitcasting to i64 should be the same thing.

> IIUC there's also some inconsistency as the current legality check fails if `ExtractElementInst` is found:
>
>   // Check that the instruction return type is vectorizable.
>   // Also, we can't vectorize extractelement instructions.
>   if ((!VectorType::isValidElementType(I.getType()) &&
>        !I.getType()->isVoidTy()) ||
>       isa<ExtractElementInst>(I)) {
>     reportVectorizationFailure("Found unvectorizable type",
>         "instruction return type cannot be vectorized",
>         "CantVectorizeInstructionReturnType", ORE, TheLoop, &I);
>     return false;
>   }
>
> which I suppose is uniform.

I'm not really familiar with this area, so i can't quite help with this.


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