[LoopRotate] Use `poison` instead of `undef` as placeholder in debug info [NFC] (#119135)

The `poison` values are used to substitute debug information of values
moved from the original header into the preheader that are no longer
available in the former.

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index 04042e7..fffff29 100644
--- a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -171,14 +171,14 @@ static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
       // Users in the OrigPreHeader need to use the value to which the
       // original definitions are mapped and anything else can be handled by
       // the SSAUpdater. To avoid adding PHINodes, check if the value is
-      // available in UserBB, if not substitute undef.
+      // available in UserBB, if not substitute poison.
       Value *NewVal;
       if (UserBB == OrigPreheader)
         NewVal = OrigPreHeaderVal;
       else if (SSA.HasValueForBlock(UserBB))
         NewVal = SSA.GetValueInMiddleOfBlock(UserBB);
       else
-        NewVal = UndefValue::get(OrigHeaderVal->getType());
+        NewVal = PoisonValue::get(OrigHeaderVal->getType());
       DbgValue->replaceVariableLocationOp(OrigHeaderVal, NewVal);
     }
 
@@ -194,14 +194,14 @@ static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
       // Users in the OrigPreHeader need to use the value to which the
       // original definitions are mapped and anything else can be handled by
       // the SSAUpdater. To avoid adding PHINodes, check if the value is
-      // available in UserBB, if not substitute undef.
+      // available in UserBB, if not substitute poison.
       Value *NewVal;
       if (UserBB == OrigPreheader)
         NewVal = OrigPreHeaderVal;
       else if (SSA.HasValueForBlock(UserBB))
         NewVal = SSA.GetValueInMiddleOfBlock(UserBB);
       else
-        NewVal = UndefValue::get(OrigHeaderVal->getType());
+        NewVal = PoisonValue::get(OrigHeaderVal->getType());
       DVR->replaceVariableLocationOp(OrigHeaderVal, NewVal);
     }
   }