[llvm] [InstCombine] Optimistically allow multiple shufflevector uses in foldOpPhi (PR #114278)

[Yingwei Zheng via llvm-commits]

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@@ -1895,17 +1916,21 @@ Instruction *InstCombinerImpl::foldOpIntoPhi(Instruction &I, PHINode *PN) {
   for (unsigned i = 0; i != NumPHIValues; ++i)
     NewPN->addIncoming(NewPhiValues[i], PN->getIncomingBlock(i));
 
-  for (User *U : make_early_inc_range(PN->users())) {
-    Instruction *User = cast<Instruction>(U);
-    if (User == &I)
-      continue;
-    replaceInstUsesWith(*User, NewPN);
-    eraseInstFromFunction(*User);
+  if (AllUsesIdentical) {
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dtcxzyw wrote:

Can you explain this change?


https://github.com/llvm/llvm-project/pull/114278