SCEV: Use AssertingVH to catch dangling BasicBlock* when passes forget
to notify SCEV of a change. Add forgetLoop in a couple of those places.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136797 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index 9af338e..9b16c7cb 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -325,6 +325,14 @@
DEBUG(dbgs() << "LoopSimplify: Eliminating exiting block "
<< ExitingBlock->getName() << "\n");
+ // If any reachable control flow within this loop has changed, notify
+ // ScalarEvolution. Currently assume the parent loop doesn't change
+ // (spliting edges doesn't count). If blocks, CFG edges, or other values
+ // in the parent loop change, then we need call to forgetLoop() for the
+ // parent instead.
+ if (SE)
+ SE->forgetLoop(L);
+
assert(pred_begin(ExitingBlock) == pred_end(ExitingBlock));
Changed = true;
LI->removeBlock(ExitingBlock);