[llvm] [VPlan] Dispatch to multiple exit blocks via middle blocks. (PR #112138)

[David Sherwood via llvm-commits]

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@@ -1056,12 +1074,19 @@ void VPlan::execute(VPTransformState *State) {
   State->CFG.DTU.applyUpdates({{DominatorTree::Delete, MiddleBB, ScalarPh}});
 
   // Generate code in the loop pre-header and body.
-  for (VPBlockBase *Block : vp_depth_first_shallow(Entry))
+  ReversePostOrderTraversal<VPBlockShallowTraversalWrapper<VPBlockBase *>> RPOT(
+      Entry);
+
+  for (VPBlockBase *Block : RPOT)
     Block->execute(State);
 
   VPBasicBlock *LatchVPBB = getVectorLoopRegion()->getExitingBasicBlock();
   BasicBlock *VectorLatchBB = State->CFG.VPBB2IRBB[LatchVPBB];
 
+  if (!getVectorLoopRegion()->getSingleSuccessor())
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david-arm wrote:

One successor only.

https://github.com/llvm/llvm-project/pull/112138