[PATCH] D111301: [VPlan] Make sure recurrence splice is not inserted between phis.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
fhahn added reviewers: Ayal, gilr.
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All phi-like recipes should be at the beginning of a VPBasicBlock with
no other recipes in between. Ensure that the recurrence-splicing recipe
is not added between phi-like recipes, but after them.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D111301

Files:
  llvm/lib/Transforms/Vectorize/LoopVectorize.cpp


Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -9442,8 +9442,13 @@
     if (auto *Region = GetReplicateRegion(PrevRecipe)) {
       VPBasicBlock *Succ = cast<VPBasicBlock>(Region->getSingleSuccessor());
       RecurSplice->moveBefore(*Succ, Succ->getFirstNonPhi());
-    } else
-      RecurSplice->moveAfter(PrevRecipe);
+    } else {
+      auto &VPBB = *PrevRecipe->getParent();
+      if (PrevRecipe->isPhi())
+        RecurSplice->moveBefore(VPBB, VPBB.getFirstNonPhi());
+      else
+        RecurSplice->moveAfter(PrevRecipe);
+    }
     RecurPhi->replaceAllUsesWith(RecurSplice);
     // Set the first operand of RecurSplice to RecurPhi again, after replacing
     // all users.


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