Make ScalarEvolution::forgetLoop forget all contained loops too, because

they may have ValuesAtScopes map entries referencing their outer loops.
This fixes a user-after-free reported in PR8471.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117698 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 5ae273e56d2f62b010b08b5e0a5a00bf56b7f1ef..4d750b4464badeba7473f4d32b45f1411cb32b8c 100644 (file)
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -3781,6 +3781,11 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
 
     PushDefUseChildren(I, Worklist);
   }
+
+  // Forget all contained loops too, to avoid dangling entries in the
+  // ValuesAtScopes map.
+  for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
+    forgetLoop(*I);
 }
 
 /// forgetValue - This method should be called by the client when it has