[llvm-branch-commits] [llvm] 67fcb4d - Revert "revert fix in #208874, keep test"

[via llvm-branch-commits]

Author: Enna1
Date: 2026-08-06T22:27:33+08:00
New Revision: 67fcb4de0cd415701ba0b4b41213ee6bec3a318e

URL: https://github.com/llvm/llvm-project/commit/67fcb4de0cd415701ba0b4b41213ee6bec3a318e
DIFF: https://github.com/llvm/llvm-project/commit/67fcb4de0cd415701ba0b4b41213ee6bec3a318e.diff

LOG: Revert "revert fix in #208874, keep test"

This reverts commit 89e43e35f9d4e4f68234767bc5d46c5736150bc6.

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/LoopUnroll.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 8c9ce101f637d..c92621a85e068 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -1284,6 +1284,10 @@ llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
   // Loop over the PHI nodes in the original block, setting incoming values.
   for (PHINode *PN : OrigPHINode) {
     if (CompletelyUnroll) {
+      // The RAUW below disconnects the original PHI from its users.
+      // Invalidate cached SCEVs while the def-use chain is still intact.
+      if (SE)
+        SE->forgetValue(PN);
       PN->replaceAllUsesWith(PN->getIncomingValueForBlock(Preheader));
       PN->eraseFromParent();
     } else if (ULO.Count > 1) {