Add a missing check to avoid dereference null. No sensible test case possible. Sorry. rdar://11745134

llvm-svn: 159236
2012-06-26 22:54:59 +00:00 · 2012-06-26 22:54:59 +00:00 · a75127871c
parent c118395cff
commit a75127871c
1 changed files with 2 additions and 0 deletions
--- a/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ b/llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@ -1802,6 +1802,8 @@ static bool isSuitableForMask(MachineInstr *&MI, unsigned SrcReg,
 bool ARMBaseInstrInfo::
 OptimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg, int CmpMask,
                     int CmpValue, const MachineRegisterInfo *MRI) const {
+  if (MRI->def_empty(SrcReg))
+    return false;

  MachineRegisterInfo::def_iterator DI = MRI->def_begin(SrcReg);
  if (llvm::next(DI) != MRI->def_end())