1 files changed, 14 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 60c76657a87..a8ba03dafff 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -6690,8 +6690,21 @@ public:
           VectorizedTree = VectReductionData.createOp(Builder, "op.extra", I);
         }
       }
-      // Update users.
+
+      // Update users. For a min/max reduction that ends with a compare and
+      // select, we also have to RAUW for the compare instruction feeding the
+      // reduction root. That's because the original compare may have extra uses
+      // besides the final select of the reduction.
+      if (ReductionData.isMinMax() && isa<SelectInst>(VectorizedTree)) {
+        assert(isa<SelectInst>(ReductionRoot) &&
+               "Expected min/max reduction to have select root instruction");
+
+        Value *ScalarCond = cast<SelectInst>(ReductionRoot)->getCondition();
+        Value *VectorCond = cast<SelectInst>(VectorizedTree)->getCondition();
+        ScalarCond->replaceAllUsesWith(VectorCond);
+      }
       ReductionRoot->replaceAllUsesWith(VectorizedTree);
+
       // Mark all scalar reduction ops for deletion, they are replaced by the
       // vector reductions.
       V.eraseInstructions(IgnoreList);