[PATCH] D68128: [InstCombine] Fold PHIs with equal incoming pointers

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

I see.
So we want to hoist identical gep+bitcast from 2 BB's into their closest dominating BB, more or less.
Do we have standalone hoisting pass?



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Comment at: llvm/lib/Transforms/InstCombine/InstCombinePHI.cpp:1157-1168
+  Instruction *InsertPt = nullptr;
+  if (auto *BaseInst = dyn_cast<Instruction>(Base)) {
+    if (isa<PHINode>(BaseInst)) {
+      BasicBlock *InsertBB = BaseInst->getParent();
+      BasicBlock::iterator InsertPtIter = InsertBB->getFirstInsertionPt();
+      // Make sure the insertion point exists.
+      if (InsertPtIter != InsertBB->end())
----------------
I'm not sure if this is correct.
I'd expect that we actually need to check to where we can move these geps.



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  https://reviews.llvm.org/D68128/new/

https://reviews.llvm.org/D68128