diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4498,7 +4498,7 @@
       // Determine the number of scalars we need to generate for each unroll
       // iteration. If the instruction is uniform, we only need to generate the
       // first lane. Otherwise, we generate all VF values.
-      bool IsUniform = Cost->isUniformAfterVectorization(P, State.VF);
+      bool IsUniform = vputils::onlyFirstLaneDemanded(PhiR);
       assert((IsUniform || !State.VF.isScalable()) &&
              "Cannot scalarize a scalable VF");
       unsigned Lanes = IsUniform ? 1 : State.VF.getFixedValue();