MachineBasicBlock::iterator
SILoadStoreOptimizer::findMatchingDSInst(MachineBasicBlock::iterator I,
unsigned EltSize,
SmallVectorImpl<MachineInstr*> &InstsToMove) {
MachineBasicBlock::iterator E = I->getParent()->end();
MachineBasicBlock::iterator MBBI = I;
++MBBI;
SmallVector<const MachineOperand *, 8> DefsToMove;
addDefsToList(*I, DefsToMove);
for ( ; MBBI != E; ++MBBI) {
if (MBBI->getOpcode() != I->getOpcode()) {
// This is not a matching DS instruction, but we can keep looking as
// long as one of these conditions are met:
// 1. It is safe to move I down past MBBI.
// 2. It is safe to move MBBI down past the instruction that I will
// be merged into.
if (MBBI->hasUnmodeledSideEffects())
// We can't re-order this instruction with respect to other memory
// opeations, so we fail both conditions mentioned above.
return E;
if (MBBI->mayLoadOrStore() &&
!TII->areMemAccessesTriviallyDisjoint(*I, *MBBI, AA)) {
// We fail condition #1, but we may still be able to satisfy condition
// #2. Add this instruction to the move list and then we will check
// if condition #2 holds once we have selected the matching instruction.
InstsToMove.push_back(&*MBBI);
addDefsToList(*MBBI, DefsToMove);
continue;
}
// When we match I with another DS instruction we will be moving I down
// to the location of the matched instruction any uses of I will need to
// be moved down as well.
for (const MachineOperand *Def : DefsToMove) {
bool ReadDef = MBBI->readsVirtualRegister(Def->getReg());
// If ReadDef is true, then there is a use of Def between I
// and the instruction that I will potentially be merged with. We
// will need to move this instruction after the merged instructions.
if (ReadDef) {
InstsToMove.push_back(&*MBBI);
addDefsToList(*MBBI, DefsToMove);
break;
}
}
continue;
}
// Don't merge volatiles.
if (MBBI->hasOrderedMemoryRef())
return E;
int AddrIdx = AMDGPU::getNamedOperandIdx(I->getOpcode(), AMDGPU::OpName::addr);
const MachineOperand &AddrReg0 = I->getOperand(AddrIdx);
const MachineOperand &AddrReg1 = MBBI->getOperand(AddrIdx);
// Check same base pointer. Be careful of subregisters, which can occur with
// vectors of pointers.
if (AddrReg0.getReg() == AddrReg1.getReg() &&
AddrReg0.getSubReg() == AddrReg1.getSubReg()) {
int OffsetIdx = AMDGPU::getNamedOperandIdx(I->getOpcode(),
AMDGPU::OpName::offset);
unsigned Offset0 = I->getOperand(OffsetIdx).getImm() & 0xffff;
unsigned Offset1 = MBBI->getOperand(OffsetIdx).getImm() & 0xffff;
// Check both offsets fit in the reduced range.
// We also need to go through the list of instructions that we plan to
// move and make sure they are all safe to move down past the merged
// instruction.
if (offsetsCanBeCombined(Offset0, Offset1, EltSize) &&
canMoveInstsAcrossMemOp(*MBBI, InstsToMove, TII, AA))
return MBBI;
}
// We've found a load/store that we couldn't merge for some reason.
// We could potentially keep looking, but we'd need to make sure that
// it was safe to move I and also all the instruction in InstsToMove
// down past this instruction.
// FIXME: This is too conservative.
break;
}
return E;
}
bool SILoadStoreOptimizer::findMatchingInst(CombineInfo &CI) {
MachineBasicBlock *MBB = CI.I->getParent();
MachineBasicBlock::iterator E = MBB->end();
MachineBasicBlock::iterator MBBI = CI.I;
const unsigned Opc = CI.I->getOpcode();
const InstClassEnum InstClass = getInstClass(Opc);
if (InstClass == UNKNOWN) {
return false;
}
const unsigned Regs = getRegs(Opc);
unsigned AddrOpName[5] = {0};
int AddrIdx[5];
const MachineOperand *AddrReg[5];
unsigned NumAddresses = 0;
if (Regs & ADDR) {
AddrOpName[NumAddresses++] = AMDGPU::OpName::addr;
}
if (Regs & SBASE) {
AddrOpName[NumAddresses++] = AMDGPU::OpName::sbase;
}
if (Regs & SRSRC) {
AddrOpName[NumAddresses++] = AMDGPU::OpName::srsrc;
}
if (Regs & SOFFSET) {
AddrOpName[NumAddresses++] = AMDGPU::OpName::soffset;
}
if (Regs & VADDR) {
AddrOpName[NumAddresses++] = AMDGPU::OpName::vaddr;
}
for (unsigned i = 0; i < NumAddresses; i++) {
AddrIdx[i] = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(), AddrOpName[i]);
AddrReg[i] = &CI.I->getOperand(AddrIdx[i]);
// We only ever merge operations with the same base address register, so
// don't bother scanning forward if there are no other uses.
if (AddrReg[i]->isReg() &&
(TargetRegisterInfo::isPhysicalRegister(AddrReg[i]->getReg()) ||
MRI->hasOneNonDBGUse(AddrReg[i]->getReg())))
return false;
}
++MBBI;
DenseSet<unsigned> RegDefsToMove;
DenseSet<unsigned> PhysRegUsesToMove;
addDefsUsesToList(*CI.I, RegDefsToMove, PhysRegUsesToMove);
for (; MBBI != E; ++MBBI) {
const bool IsDS = (InstClass == DS_READ) || (InstClass == DS_WRITE);
if ((getInstClass(MBBI->getOpcode()) != InstClass) ||
(IsDS && (MBBI->getOpcode() != Opc))) {
// This is not a matching DS instruction, but we can keep looking as
// long as one of these conditions are met:
// 1. It is safe to move I down past MBBI.
// 2. It is safe to move MBBI down past the instruction that I will
// be merged into.
if (MBBI->hasUnmodeledSideEffects()) {
// We can't re-order this instruction with respect to other memory
// operations, so we fail both conditions mentioned above.
return false;
}
if (MBBI->mayLoadOrStore() &&
(!memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA) ||
!canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))) {
// We fail condition #1, but we may still be able to satisfy condition
// #2. Add this instruction to the move list and then we will check
// if condition #2 holds once we have selected the matching instruction.
CI.InstsToMove.push_back(&*MBBI);
addDefsUsesToList(*MBBI, RegDefsToMove, PhysRegUsesToMove);
continue;
}
// When we match I with another DS instruction we will be moving I down
// to the location of the matched instruction any uses of I will need to
// be moved down as well.
addToListsIfDependent(*MBBI, RegDefsToMove, PhysRegUsesToMove,
CI.InstsToMove);
continue;
}
// Don't merge volatiles.
if (MBBI->hasOrderedMemoryRef())
return false;
// Handle a case like
// DS_WRITE_B32 addr, v, idx0
// w = DS_READ_B32 addr, idx0
// DS_WRITE_B32 addr, f(w), idx1
// where the DS_READ_B32 ends up in InstsToMove and therefore prevents
// merging of the two writes.
if (addToListsIfDependent(*MBBI, RegDefsToMove, PhysRegUsesToMove,
CI.InstsToMove))
continue;
bool Match = true;
for (unsigned i = 0; i < NumAddresses; i++) {
const MachineOperand &AddrRegNext = MBBI->getOperand(AddrIdx[i]);
if (AddrReg[i]->isImm() || AddrRegNext.isImm()) {
if (AddrReg[i]->isImm() != AddrRegNext.isImm() ||
AddrReg[i]->getImm() != AddrRegNext.getImm()) {
Match = false;
break;
}
continue;
}
// Check same base pointer. Be careful of subregisters, which can occur
// with vectors of pointers.
if (AddrReg[i]->getReg() != AddrRegNext.getReg() ||
AddrReg[i]->getSubReg() != AddrRegNext.getSubReg()) {
Match = false;
break;
}
}
if (Match) {
int OffsetIdx =
AMDGPU::getNamedOperandIdx(CI.I->getOpcode(), AMDGPU::OpName::offset);
CI.Offset0 = CI.I->getOperand(OffsetIdx).getImm();
CI.Width0 = getOpcodeWidth(*CI.I);
CI.Offset1 = MBBI->getOperand(OffsetIdx).getImm();
CI.Width1 = getOpcodeWidth(*MBBI);
CI.Paired = MBBI;
if ((CI.InstClass == DS_READ) || (CI.InstClass == DS_WRITE)) {
CI.Offset0 &= 0xffff;
CI.Offset1 &= 0xffff;
} else {
CI.GLC0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::glc)->getImm();
CI.GLC1 = TII->getNamedOperand(*MBBI, AMDGPU::OpName::glc)->getImm();
if (CI.InstClass != S_BUFFER_LOAD_IMM) {
CI.SLC0 = TII->getNamedOperand(*CI.I, AMDGPU::OpName::slc)->getImm();
CI.SLC1 = TII->getNamedOperand(*MBBI, AMDGPU::OpName::slc)->getImm();
}
}
// Check both offsets fit in the reduced range.
// We also need to go through the list of instructions that we plan to
// move and make sure they are all safe to move down past the merged
// instruction.
if (widthsFit(*STM, CI) && offsetsCanBeCombined(CI))
if (canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
return true;
}
// We've found a load/store that we couldn't merge for some reason.
// We could potentially keep looking, but we'd need to make sure that
// it was safe to move I and also all the instruction in InstsToMove
// down past this instruction.
// check if we can move I across MBBI and if we can move all I's users
if (!memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA) ||
!canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
break;
}
return false;
}
bool SILoadStoreOptimizer::findMatchingDSInst(CombineInfo &CI) {
MachineBasicBlock::iterator E = CI.I->getParent()->end();
MachineBasicBlock::iterator MBBI = CI.I;
++MBBI;
SmallVector<const MachineOperand *, 8> DefsToMove;
addDefsToList(*CI.I, DefsToMove);
for ( ; MBBI != E; ++MBBI) {
if (MBBI->getOpcode() != CI.I->getOpcode()) {
// This is not a matching DS instruction, but we can keep looking as
// long as one of these conditions are met:
// 1. It is safe to move I down past MBBI.
// 2. It is safe to move MBBI down past the instruction that I will
// be merged into.
if (MBBI->hasUnmodeledSideEffects())
// We can't re-order this instruction with respect to other memory
// opeations, so we fail both conditions mentioned above.
return false;
if (MBBI->mayLoadOrStore() &&
!memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA)) {
// We fail condition #1, but we may still be able to satisfy condition
// #2. Add this instruction to the move list and then we will check
// if condition #2 holds once we have selected the matching instruction.
CI.InstsToMove.push_back(&*MBBI);
addDefsToList(*MBBI, DefsToMove);
continue;
}
// When we match I with another DS instruction we will be moving I down
// to the location of the matched instruction any uses of I will need to
// be moved down as well.
addToListsIfDependent(*MBBI, DefsToMove, CI.InstsToMove);
continue;
}
// Don't merge volatiles.
if (MBBI->hasOrderedMemoryRef())
return false;
// Handle a case like
// DS_WRITE_B32 addr, v, idx0
// w = DS_READ_B32 addr, idx0
// DS_WRITE_B32 addr, f(w), idx1
// where the DS_READ_B32 ends up in InstsToMove and therefore prevents
// merging of the two writes.
if (addToListsIfDependent(*MBBI, DefsToMove, CI.InstsToMove))
continue;
int AddrIdx = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(),
AMDGPU::OpName::addr);
const MachineOperand &AddrReg0 = CI.I->getOperand(AddrIdx);
const MachineOperand &AddrReg1 = MBBI->getOperand(AddrIdx);
// Check same base pointer. Be careful of subregisters, which can occur with
// vectors of pointers.
if (AddrReg0.getReg() == AddrReg1.getReg() &&
AddrReg0.getSubReg() == AddrReg1.getSubReg()) {
int OffsetIdx = AMDGPU::getNamedOperandIdx(CI.I->getOpcode(),
AMDGPU::OpName::offset);
CI.Offset0 = CI.I->getOperand(OffsetIdx).getImm() & 0xffff;
CI.Offset1 = MBBI->getOperand(OffsetIdx).getImm() & 0xffff;
CI.Paired = MBBI;
// Check both offsets fit in the reduced range.
// We also need to go through the list of instructions that we plan to
// move and make sure they are all safe to move down past the merged
// instruction.
if (offsetsCanBeCombined(CI))
if (canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
return true;
}
// We've found a load/store that we couldn't merge for some reason.
// We could potentially keep looking, but we'd need to make sure that
// it was safe to move I and also all the instruction in InstsToMove
// down past this instruction.
// check if we can move I across MBBI and if we can move all I's users
if (!memAccessesCanBeReordered(*CI.I, *MBBI, TII, AA) ||
!canMoveInstsAcrossMemOp(*MBBI, CI.InstsToMove, TII, AA))
break;
}
return false;
}