private:
bool runOnMachineFunction(MachineFunction &Fn);
void AllocateBasicBlock();
+ void handleThroughOperands(MachineInstr *MI,
+ SmallVectorImpl<unsigned> &VirtDead);
int getStackSpaceFor(unsigned VirtReg, const TargetRegisterClass *RC);
bool isLastUseOfLocalReg(MachineOperand&);
return MO.isDead();
}
+// Handle special instruction operand like early clobbers and tied ops when
+// there are additional physreg defines.
+void RAFast::handleThroughOperands(MachineInstr *MI,
+ SmallVectorImpl<unsigned> &VirtDead) {
+ DEBUG(dbgs() << "Scanning for through registers:");
+ SmallSet<unsigned, 8> ThroughRegs;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg()) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ if (MO.isEarlyClobber() || MI->isRegTiedToDefOperand(i)) {
+ if (ThroughRegs.insert(Reg))
+ DEBUG(dbgs() << " %reg" << Reg);
+ }
+ }
+
+ // If any physreg defines collide with preallocated through registers,
+ // we must spill and reallocate.
+ DEBUG(dbgs() << "\nChecking for physdef collisions.\n");
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg() || !MO.isDef()) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ UsedInInstr.set(Reg);
+ if (ThroughRegs.count(PhysRegState[Reg]))
+ definePhysReg(MI, Reg, regFree);
+ for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS) {
+ UsedInInstr.set(*AS);
+ if (ThroughRegs.count(PhysRegState[*AS]))
+ definePhysReg(MI, *AS, regFree);
+ }
+ }
+
+ DEBUG(dbgs() << "Allocating tied uses and early clobbers.\n");
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg()) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg || TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ if (MO.isUse()) {
+ unsigned DefIdx = 0;
+ if (!MI->isRegTiedToDefOperand(i, &DefIdx)) continue;
+ DEBUG(dbgs() << "Operand " << i << "("<< MO << ") is tied to operand "
+ << DefIdx << ".\n");
+ LiveRegMap::iterator LRI = reloadVirtReg(MI, i, Reg, 0);
+ unsigned PhysReg = LRI->second.PhysReg;
+ setPhysReg(MI, i, PhysReg);
+ } else if (MO.isEarlyClobber()) {
+ // Note: defineVirtReg may invalidate MO.
+ LiveRegMap::iterator LRI = defineVirtReg(MI, i, Reg, 0);
+ unsigned PhysReg = LRI->second.PhysReg;
+ if (setPhysReg(MI, i, PhysReg))
+ VirtDead.push_back(Reg);
+ }
+ }
+
+ // Restore UsedInInstr to a state usable for allocating normal virtual uses.
+ UsedInInstr.reset();
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg() || (MO.isDef() && !MO.isEarlyClobber())) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ UsedInInstr.set(Reg);
+ for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
+ UsedInInstr.set(*AS);
+ }
+}
+
void RAFast::AllocateBasicBlock() {
DEBUG(dbgs() << "\nAllocating " << *MBB);
E = MBB->livein_end(); I != E; ++I)
definePhysReg(MII, *I, regReserved);
- SmallVector<unsigned, 8> PhysECs, VirtDead;
+ SmallVector<unsigned, 8> VirtDead;
SmallVector<MachineInstr*, 32> Coalesced;
// Otherwise, sequentially allocate each instruction in the MBB.
// Track registers used by instruction.
UsedInInstr.reset();
- PhysECs.clear();
// First scan.
// Mark physreg uses and early clobbers as used.
// Find the end of the virtreg operands
unsigned VirtOpEnd = 0;
+ bool hasTiedOps = false, hasEarlyClobbers = false, hasPhysDefs = false;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
if (!Reg) continue;
if (TargetRegisterInfo::isVirtualRegister(Reg)) {
VirtOpEnd = i+1;
+ if (MO.isUse())
+ hasTiedOps = hasTiedOps ||
+ TID.getOperandConstraint(i, TOI::TIED_TO) != -1;
+ else if (MO.isEarlyClobber())
+ hasEarlyClobbers = true;
continue;
}
if (!Allocatable.test(Reg)) continue;
} else if (MO.isEarlyClobber()) {
definePhysReg(MI, Reg, (MO.isImplicit() || MO.isDead()) ?
regFree : regReserved);
- PhysECs.push_back(Reg);
- }
+ hasEarlyClobbers = true;
+ } else
+ hasPhysDefs = true;
+ }
+
+ // The instruction may have virtual register operands that must be allocated
+ // the same register at use-time and def-time: early clobbers and tied
+ // operands. If there are also physical defs, these registers must avoid
+ // both physical defs and uses, making them more constrained than normal
+ // operands.
+ // We didn't detect inline asm tied operands above, so just make this extra
+ // pass for all inline asm.
+ if (MI->isInlineAsm() || hasEarlyClobbers || (hasTiedOps && hasPhysDefs)) {
+ handleThroughOperands(MI, VirtDead);
+ // Don't attempt coalescing when we have funny stuff going on.
+ CopyDst = 0;
}
// Second scan.
- // Allocate virtreg uses and early clobbers.
- // Collect VirtKills
+ // Allocate virtreg uses.
for (unsigned i = 0; i != VirtOpEnd; ++i) {
MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg()) continue;
CopySrc = (CopySrc == Reg || CopySrc == PhysReg) ? PhysReg : 0;
if (setPhysReg(MI, i, PhysReg))
killVirtReg(LRI);
- } else if (MO.isEarlyClobber()) {
- // Note: defineVirtReg may invalidate MO.
- LiveRegMap::iterator LRI = defineVirtReg(MI, i, Reg, 0);
- unsigned PhysReg = LRI->second.PhysReg;
- if (setPhysReg(MI, i, PhysReg))
- VirtDead.push_back(Reg);
- PhysECs.push_back(PhysReg);
- // Don't attempt coalescing when earlyclobbers are present.
- CopyDst = 0;
}
}
// Track registers defined by instruction - early clobbers at this point.
UsedInInstr.reset();
- for (unsigned i = 0, e = PhysECs.size(); i != e; ++i) {
- unsigned PhysReg = PhysECs[i];
- UsedInInstr.set(PhysReg);
- for (const unsigned *AS = TRI->getAliasSet(PhysReg);
- unsigned Alias = *AS; ++AS)
- UsedInInstr.set(Alias);
+ if (hasEarlyClobbers) {
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &MO = MI->getOperand(i);
+ if (!MO.isReg() || !MO.isDef()) continue;
+ unsigned Reg = MO.getReg();
+ if (!Reg || !TargetRegisterInfo::isPhysicalRegister(Reg)) continue;
+ UsedInInstr.set(Reg);
+ for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
+ UsedInInstr.set(*AS);
+ }
}
unsigned DefOpEnd = MI->getNumOperands();
projects / oota-llvm.git / blobdiff