Fix a iterator out of bounds error, that triggers rarely.

llvm-svn: 141665
diff --git a/llvm/lib/Target/CellSPU/SPUInstrInfo.cpp b/llvm/lib/Target/CellSPU/SPUInstrInfo.cpp
index 02cf9bf..007bc0e 100644
--- a/llvm/lib/Target/CellSPU/SPUInstrInfo.cpp
+++ b/llvm/lib/Target/CellSPU/SPUInstrInfo.cpp
@@ -290,6 +290,8 @@
     if (I->getOpcode() == SPU::HBRA ||
         I->getOpcode() == SPU::HBR_LABEL){
       I=MBB.erase(I);
+      if (I == MBB.end())
+        break;
     }
   }
 }