Fix crash when compiling twolf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10584 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 05b4f5a124..e4b134bc9d 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -146,7 +146,8 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock* mbb,
         unsigned liveBlockIndex = it->first;
         MachineBasicBlock* liveBlock = it->second;
         if (liveBlockIndex < vi.AliveBlocks.size() &&
-            vi.AliveBlocks[liveBlockIndex]) {
+            vi.AliveBlocks[liveBlockIndex] &&
+            !liveBlock->empty()) {
             unsigned start =  getInstructionIndex(liveBlock->front());
             unsigned end = getInstructionIndex(liveBlock->back()) + 1;
             interval->addRange(start, end);