[PATCH] D98082: [gvn] Precisely propagate equalities to phi operands

[Nikita Popov via Phabricator via llvm-commits]

nikic added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/Local.cpp:2709
+      UseBB = UserInst->getParent();
+    return DT.properlyDominates(BB, UseBB);
   };
----------------
I'd suggest to write it like this:
```
Instruction *UserInst = cast<Instruction>(U.getUser());
if (auto *PN = dyn_cast<PHINode>(UserInst))
  return DT.dominates(BB, PN->getIncomingBlock());
else
  return DT.properlyDominates(BB, UserInst->getParent());
```

Though ideally this should be an API on DominatorTree. We currently have `dominates(BasicBlockEdge, Use)`, but we're missing the `dominates(BasicBlock, Use)` variant.


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  https://reviews.llvm.org/D98082/new/

https://reviews.llvm.org/D98082