Make the peephole optimizer clear kill flags on a vreg if it's about to add new

[oota-llvm.git] / lib / CodeGen / PeepholeOptimizer.cpp

diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp
index 203f2bffb7bcbb7bcae15629d37c509741383b7d..9c5c029000c06136b910c8dc27b774db3fe1d952 100644 (file)
--- a/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/lib/CodeGen/PeepholeOptimizer.cpp
@@ -237,6 +237,10 @@ OptimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB,
       if (PHIBBs.count(UseMBB))
         continue;
 
+      // About to add uses of DstReg, clear DstReg's kill flags.
+      if (!Changed)
+        MRI->clearKillFlags(DstReg);
+
       unsigned NewVR = MRI->createVirtualRegister(RC);
       BuildMI(*UseMBB, UseMI, UseMI->getDebugLoc(),
               TII->get(TargetOpcode::COPY), NewVR)