+ if (BBI->getOperand(i).readsReg())
+ PHIVarInfo[BBI->getOperand(i + 1).getMBB()->getNumber()]
+ .push_back(BBI->getOperand(i).getReg());
+}
+
+bool LiveVariables::VarInfo::isLiveIn(const MachineBasicBlock &MBB,
+ unsigned Reg,
+ MachineRegisterInfo &MRI) {
+ unsigned Num = MBB.getNumber();
+
+ // Reg is live-through.
+ if (AliveBlocks.test(Num))
+ return true;
+
+ // Registers defined in MBB cannot be live in.
+ const MachineInstr *Def = MRI.getVRegDef(Reg);
+ if (Def && Def->getParent() == &MBB)
+ return false;
+
+ // Reg was not defined in MBB, was it killed here?
+ return findKill(&MBB);
+}
+
+bool LiveVariables::isLiveOut(unsigned Reg, const MachineBasicBlock &MBB) {
+ LiveVariables::VarInfo &VI = getVarInfo(Reg);
+
+ // Loop over all of the successors of the basic block, checking to see if
+ // the value is either live in the block, or if it is killed in the block.
+ SmallVector<MachineBasicBlock*, 8> OpSuccBlocks;
+ for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
+ E = MBB.succ_end(); SI != E; ++SI) {
+ MachineBasicBlock *SuccMBB = *SI;
+
+ // Is it alive in this successor?
+ unsigned SuccIdx = SuccMBB->getNumber();
+ if (VI.AliveBlocks.test(SuccIdx))
+ return true;
+ OpSuccBlocks.push_back(SuccMBB);
+ }
+
+ // Check to see if this value is live because there is a use in a successor
+ // that kills it.
+ switch (OpSuccBlocks.size()) {
+ case 1: {
+ MachineBasicBlock *SuccMBB = OpSuccBlocks[0];
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (VI.Kills[i]->getParent() == SuccMBB)
+ return true;
+ break;
+ }
+ case 2: {
+ MachineBasicBlock *SuccMBB1 = OpSuccBlocks[0], *SuccMBB2 = OpSuccBlocks[1];
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (VI.Kills[i]->getParent() == SuccMBB1 ||
+ VI.Kills[i]->getParent() == SuccMBB2)
+ return true;
+ break;
+ }
+ default:
+ std::sort(OpSuccBlocks.begin(), OpSuccBlocks.end());
+ for (unsigned i = 0, e = VI.Kills.size(); i != e; ++i)
+ if (std::binary_search(OpSuccBlocks.begin(), OpSuccBlocks.end(),
+ VI.Kills[i]->getParent()))
+ return true;
+ }
+ return false;