// Return true if Compare is a comparison against zero.
static bool isCompareZero(MachineInstr &Compare) {
switch (Compare.getOpcode()) {
case SystemZ::LTEBRCompare:
case SystemZ::LTDBRCompare:
case SystemZ::LTXBRCompare:
return true;
default:
if (isLoadAndTestAsCmp(Compare))
return true;
return Compare.getNumExplicitOperands() == 2 &&
Compare.getOperand(1).isImm() && Compare.getOperand(1).getImm() == 0;
}
}
bool llvm::constrainSelectedInstRegOperands(MachineInstr &I,
const TargetInstrInfo &TII,
const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) {
assert(!isPreISelGenericOpcode(I.getOpcode()) &&
"A selected instruction is expected");
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
for (unsigned OpI = 0, OpE = I.getNumExplicitOperands(); OpI != OpE; ++OpI) {
MachineOperand &MO = I.getOperand(OpI);
// There's nothing to be done on non-register operands.
if (!MO.isReg())
continue;
LLVM_DEBUG(dbgs() << "Converting operand: " << MO << '\n');
assert(MO.isReg() && "Unsupported non-reg operand");
unsigned Reg = MO.getReg();
// Physical registers don't need to be constrained.
if (TRI.isPhysicalRegister(Reg))
continue;
// Register operands with a value of 0 (e.g. predicate operands) don't need
// to be constrained.
if (Reg == 0)
continue;
// If the operand is a vreg, we should constrain its regclass, and only
// insert COPYs if that's impossible.
// constrainOperandRegClass does that for us.
MO.setReg(constrainOperandRegClass(MF, TRI, MRI, TII, RBI, I, I.getDesc(),
MO, OpI));
// Tie uses to defs as indicated in MCInstrDesc if this hasn't already been
// done.
if (MO.isUse()) {
int DefIdx = I.getDesc().getOperandConstraint(OpI, MCOI::TIED_TO);
if (DefIdx != -1 && !I.isRegTiedToUseOperand(DefIdx))
I.tieOperands(DefIdx, OpI);
}
}
return true;
}
// Fixup callee-save register save/restore instructions to take into account
// combined SP bump by adding the local stack size to the stack offsets.
static void fixupCalleeSaveRestoreStackOffset(MachineInstr &MI,
unsigned LocalStackSize) {
unsigned Opc = MI.getOpcode();
(void)Opc;
assert((Opc == AArch64::STPXi || Opc == AArch64::STPDi ||
Opc == AArch64::STRXui || Opc == AArch64::STRDui ||
Opc == AArch64::LDPXi || Opc == AArch64::LDPDi ||
Opc == AArch64::LDRXui || Opc == AArch64::LDRDui) &&
"Unexpected callee-save save/restore opcode!");
unsigned OffsetIdx = MI.getNumExplicitOperands() - 1;
assert(MI.getOperand(OffsetIdx - 1).getReg() == AArch64::SP &&
"Unexpected base register in callee-save save/restore instruction!");
// Last operand is immediate offset that needs fixing.
MachineOperand &OffsetOpnd = MI.getOperand(OffsetIdx);
// All generated opcodes have scaled offsets.
assert(LocalStackSize % 8 == 0);
OffsetOpnd.setImm(OffsetOpnd.getImm() + LocalStackSize / 8);
}
static LLT getTypeToPrint(const MachineInstr &MI, unsigned OpIdx,
SmallBitVector &PrintedTypes,
const MachineRegisterInfo &MRI) {
const MachineOperand &Op = MI.getOperand(OpIdx);
if (!Op.isReg())
return LLT{};
if (MI.isVariadic() || OpIdx >= MI.getNumExplicitOperands())
return MRI.getType(Op.getReg());
auto &OpInfo = MI.getDesc().OpInfo[OpIdx];
if (!OpInfo.isGenericType())
return MRI.getType(Op.getReg());
if (PrintedTypes[OpInfo.getGenericTypeIndex()])
return LLT{};
PrintedTypes.set(OpInfo.getGenericTypeIndex());
return MRI.getType(Op.getReg());
}
/// Whether \p MI really requires the exec state computed during analysis.
///
/// Scalar instructions must occasionally be marked WQM for correct propagation
/// (e.g. thread masks leading up to branches), but when it comes to actual
/// execution, they don't care about EXEC.
bool SIWholeQuadMode::requiresCorrectState(const MachineInstr &MI) const {
if (MI.isTerminator())
return true;
// Skip instructions that are not affected by EXEC
if (TII->isScalarUnit(MI))
return false;
// Generic instructions such as COPY will either disappear by register
// coalescing or be lowered to SALU or VALU instructions.
if (MI.isTransient()) {
if (MI.getNumExplicitOperands() >= 1) {
const MachineOperand &Op = MI.getOperand(0);
if (Op.isReg()) {
if (TRI->isSGPRReg(*MRI, Op.getReg())) {
// SGPR instructions are not affected by EXEC
return false;
}
}
}
}
return true;
}
bool InstructionSelector::constrainSelectedInstRegOperands(
MachineInstr &I, const TargetInstrInfo &TII, const TargetRegisterInfo &TRI,
const RegisterBankInfo &RBI) const {
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
MachineRegisterInfo &MRI = MF.getRegInfo();
for (unsigned OpI = 0, OpE = I.getNumExplicitOperands(); OpI != OpE; ++OpI) {
MachineOperand &MO = I.getOperand(OpI);
// There's nothing to be done on non-register operands.
if (!MO.isReg())
continue;
DEBUG(dbgs() << "Converting operand: " << MO << '\n');
assert(MO.isReg() && "Unsupported non-reg operand");
// Physical registers don't need to be constrained.
if (TRI.isPhysicalRegister(MO.getReg()))
continue;
const TargetRegisterClass *RC = TII.getRegClass(I.getDesc(), OpI, &TRI, MF);
assert(RC && "Selected inst should have regclass operand");
// If the operand is a vreg, we should constrain its regclass, and only
// insert COPYs if that's impossible.
// If the operand is a physreg, we only insert COPYs if the register class
// doesn't contain the register.
if (RBI.constrainGenericRegister(MO.getReg(), *RC, MRI))
continue;
DEBUG(dbgs() << "Constraining with COPYs isn't implemented yet");
return false;
}
return true;
}
// The CC users in CCUsers are testing the result of a comparison of some
// value X against zero and we know that any CC value produced by MI
// would also reflect the value of X. Try to adjust CCUsers so that
// they test the result of MI directly, returning true on success.
// Leave everything unchanged on failure.
bool SystemZElimCompare::
adjustCCMasksForInstr(MachineInstr *MI, MachineInstr *Compare,
SmallVectorImpl<MachineInstr *> &CCUsers) {
int Opcode = MI->getOpcode();
const MCInstrDesc &Desc = TII->get(Opcode);
unsigned MIFlags = Desc.TSFlags;
// See which compare-style condition codes are available.
unsigned ReusableCCMask = SystemZII::getCompareZeroCCMask(MIFlags);
// For unsigned comparisons with zero, only equality makes sense.
unsigned CompareFlags = Compare->getDesc().TSFlags;
if (CompareFlags & SystemZII::IsLogical)
ReusableCCMask &= SystemZ::CCMASK_CMP_EQ;
if (ReusableCCMask == 0)
return false;
unsigned CCValues = SystemZII::getCCValues(MIFlags);
assert((ReusableCCMask & ~CCValues) == 0 && "Invalid CCValues");
// Now check whether these flags are enough for all users.
SmallVector<MachineOperand *, 4> AlterMasks;
for (unsigned int I = 0, E = CCUsers.size(); I != E; ++I) {
MachineInstr *MI = CCUsers[I];
// Fail if this isn't a use of CC that we understand.
unsigned Flags = MI->getDesc().TSFlags;
unsigned FirstOpNum;
if (Flags & SystemZII::CCMaskFirst)
FirstOpNum = 0;
else if (Flags & SystemZII::CCMaskLast)
FirstOpNum = MI->getNumExplicitOperands() - 2;
else
return false;
// Check whether the instruction predicate treats all CC values
// outside of ReusableCCMask in the same way. In that case it
// doesn't matter what those CC values mean.
unsigned CCValid = MI->getOperand(FirstOpNum).getImm();
unsigned CCMask = MI->getOperand(FirstOpNum + 1).getImm();
unsigned OutValid = ~ReusableCCMask & CCValid;
unsigned OutMask = ~ReusableCCMask & CCMask;
if (OutMask != 0 && OutMask != OutValid)
return false;
AlterMasks.push_back(&MI->getOperand(FirstOpNum));
AlterMasks.push_back(&MI->getOperand(FirstOpNum + 1));
}
// All users are OK. Adjust the masks for MI.
for (unsigned I = 0, E = AlterMasks.size(); I != E; I += 2) {
AlterMasks[I]->setImm(CCValues);
unsigned CCMask = AlterMasks[I + 1]->getImm();
if (CCMask & ~ReusableCCMask)
AlterMasks[I + 1]->setImm((CCMask & ReusableCCMask) |
(CCValues & ~ReusableCCMask));
}
// CC is now live after MI.
int CCDef = MI->findRegisterDefOperandIdx(SystemZ::CC, false, true, TRI);
assert(CCDef >= 0 && "Couldn't find CC set");
MI->getOperand(CCDef).setIsDead(false);
// Clear any intervening kills of CC.
MachineBasicBlock::iterator MBBI = MI, MBBE = Compare;
for (++MBBI; MBBI != MBBE; ++MBBI)
MBBI->clearRegisterKills(SystemZ::CC, TRI);
return true;
}
