[ValueTracking] Make undef element check more precise

If we're only checking for undef, then also only look for undef
elements in the vector (rather than undef and poison).

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 08138a5..782c28c 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -7296,10 +7296,13 @@ static bool isGuaranteedNotToBeUndefOrPoison(
         isa<ConstantPointerNull>(C) || isa<Function>(C))
       return true;
 
-    if (C->getType()->isVectorTy() && !isa<ConstantExpr>(C))
-      return (!includesUndef(Kind) ? !C->containsPoisonElement()
-                                   : !C->containsUndefOrPoisonElement()) &&
-             !C->containsConstantExpression();
+    if (C->getType()->isVectorTy() && !isa<ConstantExpr>(C)) {
+      if (includesUndef(Kind) && C->containsUndefElement())
+        return false;
+      if (includesPoison(Kind) && C->containsPoisonElement())
+        return false;
+      return !C->containsConstantExpression();
+    }
   }
 
   // Strip cast operations from a pointer value.