[LICM] Kill SCEV loop dispositions if needed

SCEV caches whether SCEV expressions are loop invariant, variant or
computable.  LICM breaks this cache, almost by definition; so clear the
SCEV disposition cache if LICM changed anything.

llvm-svn: 268408

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 72f04165e66..e6ad42bb4c3 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -258,6 +258,10 @@ bool LICM::runOnLoop(Loop *L, LPPassManager &LPM) {
     LoopToAliasSetMap[L] = CurAST;
   else
     delete CurAST;
+
+  if (Changed)
+    if (auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>())
+      SEWP->getSE().forgetLoopDispositions(L);
   return Changed;
 }