Don't do code sinking on unreachable blocks. It's unprofitable and hazardous.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100455 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index e47ba7c..e659619 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -126,6 +126,11 @@
// Can't sink anything out of a block that has less than two successors.
if (MBB.succ_size() <= 1 || MBB.empty()) return false;
+ // Don't bother sinking code out of unreachable blocks. In addition to being
+ // unprofitable, it can also lead to infinite looping, because in an unreachable
+ // loop there may be nowhere to stop.
+ if (!DT->isReachableFromEntry(&MBB)) return false;
+
bool MadeChange = false;
// Walk the basic block bottom-up. Remember if we saw a store.