1 files changed, 22 insertions, 1 deletions
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index cb0f764343..c5bfcfd301 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -188,7 +188,7 @@ void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
     if (MF->getFrameInfo()->isFixedObjectIndex(FI))
       continue;
     // This stack reference was produced by instruction selection and
-    // is not a spill
+    // is not a spill.
     if (FI < LowSpillSlot)
       continue;
     assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
@@ -201,6 +201,27 @@ void VirtRegMap::RemoveMachineInstrFromMaps(MachineInstr *MI) {
   EmergencySpillMap.erase(MI);
 }
 
+bool VirtRegMap::OnlyUseOfStackSlot(const MachineInstr *MI) const {
+  for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+    const MachineOperand &MO = MI->getOperand(i);
+    if (!MO.isFI())
+      continue;
+    int FI = MO.getIndex();
+    if (MF->getFrameInfo()->isFixedObjectIndex(FI))
+      continue;
+    // This stack reference was produced by instruction selection and
+    // is not a spill.
+    if (FI < LowSpillSlot)
+      continue;
+    assert((unsigned)FI-LowSpillSlot < SpillSlotToUsesMap.size()
+           && "Invalid spill slot");
+    if (SpillSlotToUsesMap[FI - LowSpillSlot].size() != 1)
+      return false;
+  }
+
+  return true;
+}
+
 void VirtRegMap::print(std::ostream &OS, const Module* M) const {
   const TargetRegisterInfo* TRI = MF->getTarget().getRegisterInfo();