improve comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86723 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 1d89399..2d8309d 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -142,11 +142,14 @@
++BBI;
// If the terminator is the only non-phi instruction, try to nuke it.
if (BBI->isTerminator()) {
- bool Erased = LoopHeaders.erase(BB);
+ // Since TryToSimplifyUncondBranchFromEmptyBlock may delete the
+ // block, we have to make sure it isn't in the LoopHeaders set. We
+ // reinsert afterward in the rare case when the block isn't deleted.
+ bool ErasedFromLoopHeaders = LoopHeaders.erase(BB);
if (TryToSimplifyUncondBranchFromEmptyBlock(BB))
Changed = true;
- else if (Erased)
+ else if (ErasedFromLoopHeaders)
LoopHeaders.insert(BB);
}
}