[llvm] [LV] Move check if any vector insts will be generated to VPlan. (PR #96622)

[via llvm-commits]

================
@@ -4879,6 +4874,52 @@ static void emitInvalidCostRemarks(SmallVector<InstructionVFPair> InvalidCosts,
   } while (!Tail.empty());
 }
 
+static bool willGenerateVectorInstructions(VPlan &Plan, ElementCount VF,
+                                           const TargetTransformInfo &TTI) {
+  VPTypeAnalysis TypeInfo(Plan.getCanonicalIV()->getScalarType(),
+                          Plan.getCanonicalIV()->getScalarType()->getContext());
+  for (VPBasicBlock *VPBB : VPBlockUtils::blocksOnly<VPBasicBlock>(
+           vp_depth_first_shallow(Plan.getVectorLoopRegion()->getEntry()))) {
----------------
ayalz wrote:

Suffice to traverse shallow - inner regions replicate scalar values only - stopping at vector loop region's exit block?

https://github.com/llvm/llvm-project/pull/96622