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

[via llvm-commits]

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@@ -444,18 +447,18 @@ Value *VPInstruction::generatePerPart(VPTransformState &State, unsigned Part) {
       return nullptr;
 
     Value *Cond = State.get(getOperand(0), VPIteration(Part, 0));
-    VPRegionBlock *ParentRegion = getParent()->getParent();
-    VPBasicBlock *Header = ParentRegion->getEntryBasicBlock();
-
     // Replace the temporary unreachable terminator with a new conditional
-    // branch, hooking it up to backward destination for exiting blocks now and
-    // to forward destination(s) later when they are created.
+    // branch.
     BranchInst *CondBr =
         Builder.CreateCondBr(Cond, Builder.GetInsertBlock(), nullptr);
-
-    if (getParent()->isExiting())
+    if (getParent()->isExiting()) {
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ayalz wrote:

nit (mostly independent of this patch): slightly more logical to first hook up successor 0, and then optionally successor 1 - possibly early exiting.

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