+/// InstructionStoresToFI - Return true if instruction stores to the
+/// specified frame.
+static bool InstructionStoresToFI(const MachineInstr *MI, int FI) {
+ for (MachineInstr::mmo_iterator o = MI->memoperands_begin(),
+ oe = MI->memoperands_end(); o != oe; ++o) {
+ if (!(*o)->isStore() || !(*o)->getPseudoValue())
+ continue;
+ if (const FixedStackPseudoSourceValue *Value =
+ dyn_cast<FixedStackPseudoSourceValue>((*o)->getPseudoValue())) {
+ if (Value->getFrameIndex() == FI)
+ return true;
+ }
+ }
+ return false;
+}
+
+/// ProcessMI - Examine the instruction for potentai LICM candidate. Also
+/// gather register def and frame object update information.
+void MachineLICM::ProcessMI(MachineInstr *MI,
+ BitVector &PhysRegDefs,
+ BitVector &PhysRegClobbers,
+ SmallSet<int, 32> &StoredFIs,
+ SmallVectorImpl<CandidateInfo> &Candidates) {
+ bool RuledOut = false;
+ bool HasNonInvariantUse = false;
+ unsigned Def = 0;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ const MachineOperand &MO = MI->getOperand(i);
+ if (MO.isFI()) {
+ // Remember if the instruction stores to the frame index.
+ int FI = MO.getIndex();
+ if (!StoredFIs.count(FI) &&
+ MFI->isSpillSlotObjectIndex(FI) &&
+ InstructionStoresToFI(MI, FI))
+ StoredFIs.insert(FI);
+ HasNonInvariantUse = true;
+ continue;
+ }
+
+ // We can't hoist an instruction defining a physreg that is clobbered in
+ // the loop.
+ if (MO.isRegMask()) {
+ PhysRegClobbers.setBitsNotInMask(MO.getRegMask());
+ continue;
+ }
+
+ if (!MO.isReg())
+ continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg)
+ continue;
+ assert(TargetRegisterInfo::isPhysicalRegister(Reg) &&
+ "Not expecting virtual register!");
+
+ if (!MO.isDef()) {
+ if (Reg && (PhysRegDefs.test(Reg) || PhysRegClobbers.test(Reg)))
+ // If it's using a non-loop-invariant register, then it's obviously not
+ // safe to hoist.
+ HasNonInvariantUse = true;
+ continue;
+ }
+
+ if (MO.isImplicit()) {
+ for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+ PhysRegClobbers.set(*AI);
+ if (!MO.isDead())
+ // Non-dead implicit def? This cannot be hoisted.
+ RuledOut = true;
+ // No need to check if a dead implicit def is also defined by
+ // another instruction.
+ continue;
+ }
+
+ // FIXME: For now, avoid instructions with multiple defs, unless
+ // it's a dead implicit def.
+ if (Def)
+ RuledOut = true;
+ else
+ Def = Reg;
+
+ // If we have already seen another instruction that defines the same
+ // register, then this is not safe. Two defs is indicated by setting a
+ // PhysRegClobbers bit.
+ for (MCRegAliasIterator AS(Reg, TRI, true); AS.isValid(); ++AS) {
+ if (PhysRegDefs.test(*AS))
+ PhysRegClobbers.set(*AS);
+ PhysRegDefs.set(*AS);
+ }
+ if (PhysRegClobbers.test(Reg))
+ // MI defined register is seen defined by another instruction in
+ // the loop, it cannot be a LICM candidate.
+ RuledOut = true;
+ }
+
+ // Only consider reloads for now and remats which do not have register
+ // operands. FIXME: Consider unfold load folding instructions.
+ if (Def && !RuledOut) {
+ int FI = INT_MIN;
+ if ((!HasNonInvariantUse && IsLICMCandidate(*MI)) ||
+ (TII->isLoadFromStackSlot(MI, FI) && MFI->isSpillSlotObjectIndex(FI)))
+ Candidates.push_back(CandidateInfo(MI, Def, FI));
+ }
+}
+
+/// HoistRegionPostRA - Walk the specified region of the CFG and hoist loop
+/// invariants out to the preheader.
+void MachineLICM::HoistRegionPostRA() {
+ MachineBasicBlock *Preheader = getCurPreheader();
+ if (!Preheader)
+ return;