[llvm] [VPlan] Handle early exit before forming regions. (NFC) (PR #138393)

[via llvm-commits]

================
@@ -2488,64 +2488,86 @@ void VPlanTransforms::convertToConcreteRecipes(VPlan &Plan,
     R->eraseFromParent();
 }
 
-void VPlanTransforms::handleUncountableEarlyExit(
-    VPlan &Plan, Loop *OrigLoop, BasicBlock *UncountableExitingBlock,
-    VPRecipeBuilder &RecipeBuilder, VFRange &Range) {
-  VPRegionBlock *LoopRegion = Plan.getVectorLoopRegion();
-  auto *LatchVPBB = cast<VPBasicBlock>(LoopRegion->getExiting());
+void VPlanTransforms::handleUncountableEarlyExit(VPlan &Plan,
+                                                 VPBasicBlock *HeaderVPBB,
+                                                 VPBasicBlock *LatchVPBB,
+                                                 VFRange &Range) {
+  // First find the uncountable early exiting block by looking at the
+  // predecessors of the exit blocks.
+  VPBlockBase *MiddleVPBB = LatchVPBB->getSuccessors()[0];
+  VPBasicBlock *EarlyExitingVPBB = nullptr;
+  VPIRBasicBlock *EarlyExitVPBB = nullptr;
+  for (auto *EB : Plan.getExitBlocks()) {
+    for (VPBlockBase *Pred : EB->getPredecessors()) {
+      if (Pred != MiddleVPBB) {
----------------
ayalz wrote:

Similar to the loop looking for early exit edges in the caller, common to dealing with them by sinking to scalar epilog?

https://github.com/llvm/llvm-project/pull/138393