+#ifndef NDEBUG
+/// isLiveInButUnusedBefore - Return true if register is livein the MBB not
+/// not used before it reaches the MI that defines register.
+static bool isLiveInButUnusedBefore(unsigned Reg, MachineInstr *MI,
+ MachineBasicBlock *MBB,
+ const TargetRegisterInfo *TRI,
+ MachineRegisterInfo* MRI) {
+ // First check if register is livein.
+ bool isLiveIn = false;
+ for (MachineBasicBlock::const_livein_iterator I = MBB->livein_begin(),
+ E = MBB->livein_end(); I != E; ++I)
+ if (Reg == *I || TRI->isSuperRegister(Reg, *I)) {
+ isLiveIn = true;
+ break;
+ }
+ if (!isLiveIn)
+ return false;
+
+ // Is there any use of it before the specified MI?
+ SmallPtrSet<MachineInstr*, 4> UsesInMBB;
+ for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
+ UE = MRI->use_end(); UI != UE; ++UI) {
+ MachineOperand &UseMO = UI.getOperand();
+ if (UseMO.isReg() && UseMO.isUndef())
+ continue;
+ MachineInstr *UseMI = &*UI;
+ if (UseMI->getParent() == MBB)
+ UsesInMBB.insert(UseMI);
+ }
+ if (UsesInMBB.empty())
+ return true;
+
+ for (MachineBasicBlock::iterator I = MBB->begin(), E = MI; I != E; ++I)
+ if (UsesInMBB.count(&*I))
+ return false;
+ return true;
+}
+#endif
+