[llvm] [LV] Cache call vectorization decisions (PR #66521)

[David Sherwood via llvm-commits]

================
@@ -6970,6 +6968,122 @@ void LoopVectorizationCostModel::setCostBasedWideningDecision(ElementCount VF) {
   }
 }
 
+void LoopVectorizationCostModel::setVectorizedCallDecision(ElementCount VF) {
+  if (VF.isScalar())
----------------
david-arm wrote:

This function is only called from collectUniformsAndScalars for non-scalar VFs, so I think you can simply assert that the VF is scalar.

https://github.com/llvm/llvm-project/pull/66521