[PATCH] D114779: [LV] Remove `LoopVectorizationCostModel::useEmulatedMaskMemRefHack()`

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

OK Cool.

> This is a correctness fix. It will not be at all surprising to learn that
> some other architecture has started to unintentionally rely on this
> erroneous behavior instead of implementing a correct and precise cost model.

Sure. I just think that one of the architectures relying on this, at least in places, is X86. I was honestly surprised this didn't hurt performance in more places, I thought it was still pretty important. Hence me asking what kind of performance you had run. But it looks from these very tests that it's still needed for some things and I got reports of a few more. The X86 cases did seem to be hidden more by other costs, like the cost of a vector mul being 6 :)


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  https://reviews.llvm.org/D114779/new/

https://reviews.llvm.org/D114779