1 files changed, 8 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
index af07f8f948f..92420e697ce 100644
--- a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -373,6 +373,13 @@ LaneBitmask ScheduleDAGInstrs::getLaneMaskForMO(const MachineOperand &MO) const
   return TRI->getSubRegIndexLaneMask(SubReg);
 }
 
+bool ScheduleDAGInstrs::deadDefHasNoUse(const MachineOperand &MO) {
+  auto RegUse = CurrentVRegUses.find(MO.getReg());
+  if (RegUse == CurrentVRegUses.end())
+    return true;
+  return (RegUse->LaneMask & getLaneMaskForMO(MO)).none();
+}
+
 /// Adds register output and data dependencies from this SUnit to instructions
 /// that occur later in the same scheduling region if they read from or write to
 /// the virtual register defined at OperIdx.
@@ -402,8 +409,7 @@ void ScheduleDAGInstrs::addVRegDefDeps(SUnit *SU, unsigned OperIdx) {
   }
 
   if (MO.isDead()) {
-    assert(CurrentVRegUses.find(Reg) == CurrentVRegUses.end() &&
-           "Dead defs should have no uses");
+    assert(deadDefHasNoUse(MO) && "Dead defs should have no uses");
   } else {
     // Add data dependence to all uses we found so far.
     const TargetSubtargetInfo &ST = MF.getSubtarget();