[llvm] [LoopDeletion] RAUW single-entry header phis after breakLoopBackedge. (PR #106046)

[Nikita Popov via llvm-commits]

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@@ -759,6 +759,13 @@ void llvm::breakLoopBackedge(Loop *L, DominatorTree &DT, ScalarEvolution &SE,
         DomTreeUpdater DTU(&DT, DomTreeUpdater::UpdateStrategy::Eager);
         Header->removePredecessor(Latch, true);
 
+        for (PHINode &PN : Header->phis()) {
+          assert(PN.getNumIncomingValues() == 1 &&
+                 "header phi has more than one incoming value after removing "
+                 "single latch");
+          PN.replaceAllUsesWith(PN.getIncomingValue(0));
+        }
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nikic wrote:

Shouldn't this also happen in the generic (SplitEdge) case?

https://github.com/llvm/llvm-project/pull/106046