[llvm] [VPlan] Compute interleave count for VPlan. (PR #149702)

[Alexey Bataev via llvm-commits]

================
@@ -4622,32 +4615,36 @@ LoopVectorizationCostModel::selectInterleaveCount(VPlan &Plan, ElementCount VF,
   // 3. We don't interleave if we think that we will spill registers to memory
   // due to the increased register pressure.
 
-  if (!isScalarEpilogueAllowed())
+  if (!CM.isScalarEpilogueAllowed())
     return 1;
 
-  // Do not interleave if EVL is preferred and no User IC is specified.
-  if (foldTailWithEVL()) {
+  if (any_of(Plan.getVectorLoopRegion()->getEntryBasicBlock()->phis(),
+             IsaPred<VPEVLBasedIVPHIRecipe>)) {
----------------
alexey-bataev wrote:

Why not `CM.foldTailWithEVL()`?

https://github.com/llvm/llvm-project/pull/149702