[llvm] [VPlan] Model branch cond to enter scalar epilogue in VPlan. (PR #92651)

[via llvm-commits]

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@@ -7458,6 +7403,21 @@ LoopVectorizationPlanner::executePlan(
   std::tie(State.CFG.PrevBB, CanonicalIVStartValue) =
       ILV.createVectorizedLoopSkeleton(ExpandedSCEVs ? *ExpandedSCEVs
                                                      : State.ExpandedSCEVs);
+#ifdef EXPENSIVE_CHECKS
+  assert(DT->verify(DominatorTree::VerificationLevel::Fast));
+#endif
+
+  VPBasicBlock *MiddleVPBB =
+      cast<VPBasicBlock>(BestVPlan.getVectorLoopRegion()->getSingleSuccessor());
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ayalz wrote:

Replacing VPBB with VPIRBB should also be fine. What happens if the replacement is missing? If IRBB is to be set late, it can be asserted to exist.

https://github.com/llvm/llvm-project/pull/92651