[PATCH] D41096: [X86] Initial support for prefer-vector-width function attribute

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

@hfinkel, sorry our updates passed each other.

I see your point, we shouldn't release the preference just because the user did something explicit. So in that case we would need to unconstrain the legalizer, but still keep the TTI interface reporting 256 so the vectorizer won't go out of its way to generate large vectors in the same function. And potentially add more cost modeling enhancements and potentially spot fixes into the codegen lowering.

So we probably do need another function attribute to indicate the safe width for the legalizer.


https://reviews.llvm.org/D41096