[llvm] [Assignment Tracking] Change placeholder from `undef` to `poison` (PR #119760)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-ir

Author: Pedro Lobo (pedroclobo)

<details>
<summary>Changes</summary>

Empty metadata address components of `dbg.assign` can be represented as `poison` values instead of `undef` values.

---
Full diff: https://github.com/llvm/llvm-project/pull/119760.diff


1 Files Affected:

- (modified) llvm/lib/IR/IntrinsicInst.cpp (+2-2) 


``````````diff
diff --git a/llvm/lib/IR/IntrinsicInst.cpp b/llvm/lib/IR/IntrinsicInst.cpp
index 002bab8e079e50..79795e5691f865 100644
--- a/llvm/lib/IR/IntrinsicInst.cpp
+++ b/llvm/lib/IR/IntrinsicInst.cpp
@@ -223,12 +223,12 @@ void DbgAssignIntrinsic::setAddress(Value *V) {
 void DbgAssignIntrinsic::setKillAddress() {
   if (isKillAddress())
     return;
-  setAddress(UndefValue::get(getAddress()->getType()));
+  setAddress(PoisonValue::get(getAddress()->getType()));
 }
 
 bool DbgAssignIntrinsic::isKillAddress() const {
   Value *Addr = getAddress();
-  return !Addr || isa<UndefValue>(Addr);
+  return !Addr || isa<PoisonValue>(Addr);
 }
 
 void DbgAssignIntrinsic::setValue(Value *V) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/119760