[PATCH] D114766: If constrained intrinsic is replaced, remove its side effect

[Kevin P. Neal via Phabricator via llvm-commits]

kpn added a comment.

In D114766#3161680 <https://reviews.llvm.org/D114766#3161680>, @sepavloff wrote:

> Moving this logic to `wouldInstructionBeTriviallyDead()` does not seem right, because the decision about removing side effect comes from constant evaluation and not from the state of call object.

I'm sympathetic to this argument. If a transformation pass determines that a constrained intrinsic can be removed then it would be helpful if that pass could note that fact. This doesn't help us with analysis passes, though. And I'm a little worried about having to explicitly mark constrained intrinsics as removable since I don't know that we do that for any other instruction. If constrained intrinsics are the only time we do this then it seems error prone. Maybe I'm wrong?


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