1 files changed, 41 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
index e5b422e0b7e..61ae3b75ab5 100644
--- a/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
+++ b/llvm/lib/CodeGen/ReachingDefAnalysis.cpp
@@ -231,15 +231,15 @@ void ReachingDefAnalysis::getReachingLocalUses(MachineInstr *Def, int PhysReg,
   MachineBasicBlock *MBB = Def->getParent();
   MachineBasicBlock::iterator MI = MachineBasicBlock::iterator(Def);
   while (++MI != MBB->end()) {
+    // If/when we find a new reaching def, we know that there's no more uses
+    // of 'Def'.
+    if (getReachingMIDef(&*MI, PhysReg) != Def)
+      return;
+
     for (auto &MO : MI->operands()) {
       if (!MO.isReg() || !MO.isUse() || MO.getReg() != PhysReg)
         continue;
 
-      // If/when we find a new reaching def, we know that there's no more uses
-      // of 'Def'.
-      if (getReachingMIDef(&*MI, PhysReg) != Def)
-        return;
-
       Uses.push_back(&*MI);
       if (MO.isKill())
         return;
@@ -272,6 +272,42 @@ bool ReachingDefAnalysis::isRegUsedAfter(MachineInstr *MI, int PhysReg) {
   return false;
 }
 
+bool ReachingDefAnalysis::isReachingDefLiveOut(MachineInstr *MI, int PhysReg) {
+  MachineBasicBlock *MBB = MI->getParent();
+  LivePhysRegs LiveRegs(*TRI);
+  LiveRegs.addLiveOuts(*MBB);
+  if (!LiveRegs.contains(PhysReg))
+    return false;
+
+  MachineInstr *Last = &MBB->back();
+  int Def = getReachingDef(MI, PhysReg);
+  if (getReachingDef(Last, PhysReg) != Def)
+    return false;
+
+  // Finally check that the last instruction doesn't redefine the register.
+  for (auto &MO : Last->operands())
+    if (MO.isReg() && MO.isDef() && MO.getReg() == PhysReg)
+      return false;
+
+  return true;
+}
+
+MachineInstr* ReachingDefAnalysis::getLocalLiveOutMIDef(MachineBasicBlock *MBB,
+                                                        int PhysReg) {
+  LivePhysRegs LiveRegs(*TRI);
+  LiveRegs.addLiveOuts(*MBB);
+  if (!LiveRegs.contains(PhysReg))
+    return nullptr;
+
+  MachineInstr *Last = &MBB->back();
+  int Def = getReachingDef(Last, PhysReg);
+  for (auto &MO : Last->operands())
+    if (MO.isReg() && MO.isDef() && MO.getReg() == PhysReg)
+      return Last;
+
+  return Def < 0 ? nullptr : getInstFromId(MBB, Def);
+}
+
 MachineInstr *ReachingDefAnalysis::getInstWithUseBefore(MachineInstr *MI,
     int PhysReg) {
   auto I = MachineBasicBlock::reverse_iterator(MI);