[PATCH] D100464: [DSE] Remove stores in the same loop iteration

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp:1409
+              LI.getLoopFor(KillingDef->getBlock()) &&
           !IsGuaranteedLoopInvariant(const_cast<Value *>(CurrentLoc->Ptr))) {
+        LLVM_DEBUG(dbgs() << "  ... not guaranteed loop invariant\n");
----------------
I'm not sure this logic is correct. The problem I see is that LoopInfo only tracks natural loops. This means that even though Current and KillingDef might be in the same natural loop (say the nullptr loop), Current might still be part of a (non-natural) cycle, in which case KillingDef may not kill it.

I'm not particularly familiar with LoopInfo, but that's my understanding of how it works.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D100464/new/

https://reviews.llvm.org/D100464