1 files changed, 4 insertions, 5 deletions
diff --git a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
index a3122763806..4195f007d43 100644
--- a/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -506,20 +506,19 @@ void LiveIntervals::shrinkToUses(LiveInterval::SubRange &SR, unsigned Reg) {
 
   // Visit all instructions reading Reg.
   SlotIndex LastIdx;
-  for (MachineOperand &MO : MRI->reg_operands(Reg)) {
-    MachineInstr *UseMI = MO.getParent();
-    if (UseMI->isDebugValue() || !MO.readsReg())
+  for (MachineOperand &MO : MRI->use_nodbg_operands(Reg)) {
+    // Skip "undef" uses.
+    if (!MO.readsReg())
       continue;
     // Maybe the operand is for a subregister we don't care about.
     unsigned SubReg = MO.getSubReg();
     if (SubReg != 0) {
       LaneBitmask LaneMask = TRI->getSubRegIndexLaneMask(SubReg);
-      if (MO.isDef())
-        LaneMask = ~LaneMask & MRI->getMaxLaneMaskForVReg(Reg);
       if ((LaneMask & SR.LaneMask) == 0)
         continue;
     }
     // We only need to visit each instruction once.
+    MachineInstr *UseMI = MO.getParent();
     SlotIndex Idx = getInstructionIndex(*UseMI).getRegSlot();
     if (Idx == LastIdx)
       continue;