[llvm] [GlobalOpt] Handle operators separately when removing GV users (PR #84694)

[Eli Friedman via llvm-commits]

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@@ -202,60 +212,51 @@ CleanupPointerRootUsers(GlobalVariable *GV,
 
   bool Changed = false;
 
-  // If Dead[n].first is the only use of a malloc result, we can delete its
-  // chain of computation and the store to the global in Dead[n].second.
-  SmallVector<std::pair<Instruction *, Instruction *>, 32> Dead;
+  auto RemoveComputationChain = [&GetTLI](Instruction *I) {
+    do {
+      if (isAllocationFn(I, GetTLI))
+        break;
+      Instruction *J = dyn_cast<Instruction>(I->getOperand(0));
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efriedma-quic wrote:

Can this cast actually fail?  isSafeComputationToRemove is supposed to check for a series of single-operand operations leading to an allocation.

https://github.com/llvm/llvm-project/pull/84694