diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -11229,7 +11229,7 @@
             return OptimizationRemarkMissed(
                        SV_NAME, "HorSLPNotBeneficial",
                        ReducedValsToOps.find(VL[0])->second.front())
-                   << "Vectorizing horizontal reduction is possible"
+                   << "Vectorizing horizontal reduction is possible "
                    << "but not beneficial with cost " << ore::NV("Cost", Cost)
                    << " and threshold "
                    << ore::NV("Threshold", -SLPCostThreshold);