[LoopUnroll] Forget exit values when making changes.

When unrolling, the exit values in LCSSA phis will get updated.
Invalidate cached SCEV values for those phis in case SCEV looked through
a exit phi.

Fixes #58340.

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 6d6c3db..fd874db 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -578,6 +578,7 @@ LoopUnrollResult llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
           if (It != LastValueMap.end())
             Incoming = It->second;
           PHI.addIncoming(Incoming, New);
+          SE->forgetValue(&PHI);
         }
       }
       // Keep track of new headers and latches as we create them, so that