[llvm] [VPlan] Add new VPIRPhi overlay for VPIRInsts wrapping phi nodes (NFC). (PR #129387)

[via llvm-commits]

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@@ -9131,20 +9131,19 @@ collectUsersInExitBlocks(Loop *OrigLoop, VPRecipeBuilder &Builder,
       continue;
 
     for (VPRecipeBase &R : *ExitVPBB) {
-      auto *ExitIRI = dyn_cast<VPIRInstruction>(&R);
+      auto *ExitIRI = dyn_cast<VPIRPhi>(&R);
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ayalz wrote:

Supporting non VPIRInstruction recipes introduced inside ExitVPBB, which admittedly has yet to be exercised, is dropped? Worth a comment?

https://github.com/llvm/llvm-project/pull/129387