llvm-project

f3932114 - [Reland][IPO] Added attributor for identifying invariant loads (#146584)

[Reland][IPO] Added attributor for identifying invariant loads (#146584) Patched and tested the `AAInvariantLoadPointer` attributor from #141800, which identifies pointers whose loads are eligible to be marked as `!invariant.load`. The bug in the attributor was due to `AAMemoryBehavior` always identifying pointers obtained from `alloca`s as having no writes. I'm not entirely sure why `AAMemoryBehavior` behaves this way, but it seems to be beceause it identifies the scope of an `alloca` to be limited to only that instruction (and, certainly, no memory writes occur within the `alloca` instructin). This patch just adds a check to disallow all loads from `alloca` pointers from being marked `!invariant.load` (since any well-defined program will have to write to stack pointers at some point).