[llvm] [LV] Update incoming blocks in VPWidenPHIRecipe in reassociateBlocks (PR #125481)

[Florian Hahn via llvm-commits]

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@@ -169,8 +169,19 @@ class VPBlockUtils {
   static void reassociateBlocks(VPBlockBase *Old, VPBlockBase *New) {
     for (auto *Pred : to_vector(Old->getPredecessors()))
       Pred->replaceSuccessor(Old, New);
-    for (auto *Succ : to_vector(Old->getSuccessors()))
+    for (auto *Succ : to_vector(Old->getSuccessors())) {
       Succ->replacePredecessor(Old, New);
+
+      // Replace any references to Old in widened phi incoming blocks.
+      while (auto *Region = dyn_cast<VPRegionBlock>(Succ))
+        Succ = Region->getEntry();
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fhahn wrote:

can you use `Succ->getEntryBasicBlock()`?

https://github.com/llvm/llvm-project/pull/125481