[clang] [llvm] [PromoteMemToReg] Insert store undef when removing lifetime markers (PR #191909)

[Nikita Popov via cfe-commits]

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@@ -546,9 +545,20 @@ static void removeIntrinsicUsers(AllocaInst *AI) {
           Inst->dropDroppableUse(UU);
           continue;
         }
+
         Inst->eraseFromParent();
       }
     }
+
+    // Same as above for lifetime intrinsics directly on the alloca.
+    if (auto *II = dyn_cast<IntrinsicInst>(I))
+      if (II->isLifetimeStartOrEnd()) {
+        auto *Store = new StoreInst(UndefValue::get(AI->getAllocatedType()), AI,
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nikic wrote:

This needs to use the common type of all loads/stores, rather than the allocated type, which is not required to be the same.

https://github.com/llvm/llvm-project/pull/191909