SCEV should forget all loops containing a deleted block.

Summary:
LoopSimplifyCFG should update ScEv for all loops after a block is deleted.
If the deleted block "Succ" is part of L, then it is part of all parent loops, so forget topmost loop.

Reviewers: greened, mkazantsev, sanjoy

Subscribers: jlebar, javed.absar, uabelho, llvm-commits

Differential Revision: https://reviews.llvm.org/D50422

llvm-svn: 339363

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
index 3f31d8efeb4..65e051c4a7a 100644
--- a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
@@ -61,7 +61,8 @@ static bool simplifyLoopCFG(Loop &L, DominatorTree &DT, LoopInfo &LI,
     // Merge Succ into Pred and delete it.
     MergeBlockIntoPredecessor(Succ, &DTU, &LI);
 
-    SE.forgetLoop(&L);
+    SE.forgetTopmostLoop(&L);
+
     Changed = true;
   }