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Implement review feedback. No functionality change. 

llvm-svn: 40863
This commit is contained in:
Christopher Lamb 2007-08-06 16:33:56 +00:00
parent 77b2accbca
commit 2e5fb9f71e
2 changed files with 153 additions and 138 deletions
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2
llvm/include/llvm/CodeGen/Passes.h
View File

@ -90,7 +90,7 @@ namespace llvm {
FunctionPass *createPrologEpilogCodeInserter();
/// LowerSubregs Pass - This pass lowers subregs to register-register copies
/// which yields suboptimial, but correct code if the register allocator
/// which yields suboptimal, but correct code if the register allocator
/// cannot coalesce all subreg operations during allocation.
///
FunctionPass *createLowerSubregsPass();

289
llvm/lib/CodeGen/LowerSubregs.cpp
View File

@ -32,6 +32,9 @@ namespace {
/// runOnMachineFunction - pass entry point
bool runOnMachineFunction(MachineFunction&);
bool LowerExtract(MachineInstr *MI);
bool LowerInsert(MachineInstr *MI);
};
char LowerSubregsInstructionPass::ID = 0;
@ -41,7 +44,7 @@ FunctionPass *llvm::createLowerSubregsPass() {
return new LowerSubregsInstructionPass();
}
// Returns the Register Class of a physical register
// Returns the Register Class of a physical register.
static const TargetRegisterClass *getPhysicalRegisterRegClass(
const MRegisterInfo &MRI,
unsigned reg) {
@ -67,14 +70,153 @@ static bool isSubRegOf(const MRegisterInfo &MRI,
return false;
}
bool LowerSubregsInstructionPass::LowerExtract(MachineInstr *MI) {
MachineBasicBlock *MBB = MI->getParent();
MachineFunction &MF = *MBB->getParent();
const MRegisterInfo &MRI = *MF.getTarget().getRegisterInfo();
assert(MI->getOperand(0).isRegister() && MI->getOperand(0).isDef() &&
MI->getOperand(1).isRegister() && MI->getOperand(1).isUse() &&
MI->getOperand(2).isImm() && "Malformed extract_subreg");
unsigned SuperReg = MI->getOperand(1).getReg();
unsigned SubIdx = MI->getOperand(2).getImm();
assert(MRegisterInfo::isPhysicalRegister(SuperReg) &&
"Extract supperg source must be a physical register");
unsigned SrcReg = MRI.getSubReg(SuperReg, SubIdx);
unsigned DstReg = MI->getOperand(0).getReg();
DOUT << "subreg: CONVERTING: " << *MI;
if (SrcReg != DstReg) {
const TargetRegisterClass *TRC = 0;
if (MRegisterInfo::isPhysicalRegister(DstReg)) {
TRC = getPhysicalRegisterRegClass(MRI, DstReg);
} else {
TRC = MF.getSSARegMap()->getRegClass(DstReg);
}
assert(TRC == getPhysicalRegisterRegClass(MRI, SrcReg) &&
"Extract subreg and Dst must be of same register class");
MRI.copyRegToReg(*MBB, MI, DstReg, SrcReg, TRC);
MachineBasicBlock::iterator dMI = MI;
DOUT << "subreg: " << *(--dMI);
}
DOUT << "\n";
MBB->erase(MI);
return true;
}
bool LowerSubregsInstructionPass::LowerInsert(MachineInstr *MI) {
MachineBasicBlock *MBB = MI->getParent();
MachineFunction &MF = *MBB->getParent();
const MRegisterInfo &MRI = *MF.getTarget().getRegisterInfo();
unsigned DstReg = 0;
unsigned SrcReg = 0;
unsigned InsReg = 0;
unsigned SubIdx = 0;
// If only have 3 operands, then the source superreg is undef
// and we can supress the copy from the undef value
if (MI->getNumOperands() == 3) {
assert((MI->getOperand(0).isRegister() && MI->getOperand(0).isDef()) &&
(MI->getOperand(1).isRegister() && MI->getOperand(1).isUse()) &&
MI->getOperand(2).isImm() && "Invalid extract_subreg");
DstReg = MI->getOperand(0).getReg();
SrcReg = DstReg;
InsReg = MI->getOperand(1).getReg();
SubIdx = MI->getOperand(2).getImm();
} else if (MI->getNumOperands() == 4) {
assert((MI->getOperand(0).isRegister() && MI->getOperand(0).isDef()) &&
(MI->getOperand(1).isRegister() && MI->getOperand(1).isUse()) &&
(MI->getOperand(2).isRegister() && MI->getOperand(2).isUse()) &&
MI->getOperand(3).isImm() && "Invalid extract_subreg");
DstReg = MI->getOperand(0).getReg();
SrcReg = MI->getOperand(1).getReg();
InsReg = MI->getOperand(2).getReg();
SubIdx = MI->getOperand(3).getImm();
} else
assert(0 && "Malformed extract_subreg");
assert(SubIdx != 0 && "Invalid index for extract_subreg");
unsigned DstSubReg = MRI.getSubReg(DstReg, SubIdx);
assert(MRegisterInfo::isPhysicalRegister(SrcReg) &&
"Insert superreg source must be in a physical register");
assert(MRegisterInfo::isPhysicalRegister(DstReg) &&
"Insert destination must be in a physical register");
assert(MRegisterInfo::isPhysicalRegister(InsReg) &&
"Inserted value must be in a physical register");
DOUT << "subreg: CONVERTING: " << *MI;
// If the inserted register is already allocated into a subregister
// of the destination, we copy the subreg into the source
// However, this is only safe if the insert instruction is the kill
// of the source register
bool revCopyOrder = isSubRegOf(MRI, InsReg, DstReg);
if (revCopyOrder) {
if (MI->getOperand(1).isKill()) {
DstSubReg = MRI.getSubReg(SrcReg, SubIdx);
// Insert sub-register copy
const TargetRegisterClass *TRC1 = 0;
if (MRegisterInfo::isPhysicalRegister(InsReg)) {
TRC1 = getPhysicalRegisterRegClass(MRI, InsReg);
} else {
TRC1 = MF.getSSARegMap()->getRegClass(InsReg);
}
MRI.copyRegToReg(*MBB, MI, DstSubReg, InsReg, TRC1);
MachineBasicBlock::iterator dMI = MI;
DOUT << "subreg: " << *(--dMI);
} else {
assert(0 && "Don't know how to convert this insert");
}
}
if (SrcReg != DstReg) {
// Insert super-register copy
const TargetRegisterClass *TRC0 = 0;
if (MRegisterInfo::isPhysicalRegister(DstReg)) {
TRC0 = getPhysicalRegisterRegClass(MRI, DstReg);
} else {
TRC0 = MF.getSSARegMap()->getRegClass(DstReg);
}
assert(TRC0 == getPhysicalRegisterRegClass(MRI, SrcReg) &&
"Insert superreg and Dst must be of same register class");
MRI.copyRegToReg(*MBB, MI, DstReg, SrcReg, TRC0);
MachineBasicBlock::iterator dMI = MI;
DOUT << "subreg: " << *(--dMI);
}
if (!revCopyOrder && InsReg != DstSubReg) {
// Insert sub-register copy
const TargetRegisterClass *TRC1 = 0;
if (MRegisterInfo::isPhysicalRegister(InsReg)) {
TRC1 = getPhysicalRegisterRegClass(MRI, InsReg);
} else {
TRC1 = MF.getSSARegMap()->getRegClass(InsReg);
}
MRI.copyRegToReg(*MBB, MI, DstSubReg, InsReg, TRC1);
MachineBasicBlock::iterator dMI = MI;
DOUT << "subreg: " << *(--dMI);
}
DOUT << "\n";
MBB->erase(MI);
return true;
}
/// runOnMachineFunction - Reduce subregister inserts and extracts to register
/// copies.
///
bool LowerSubregsInstructionPass::runOnMachineFunction(MachineFunction &MF) {
DOUT << "Machine Function\n";
const TargetMachine &TM = MF.getTarget();
const MRegisterInfo &MRI = *TM.getRegisterInfo();
bool MadeChange = false;
@ -84,140 +226,13 @@ bool LowerSubregsInstructionPass::runOnMachineFunction(MachineFunction &MF) {
for (MachineFunction::iterator mbbi = MF.begin(), mbbe = MF.end();
mbbi != mbbe; ++mbbi) {
for (MachineBasicBlock::iterator mi = mbbi->begin(), me = mbbi->end();
mi != me; ++mi) {
if (mi->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG) {
assert(mi->getOperand(0).isRegister() && mi->getOperand(0).isDef() &&
mi->getOperand(1).isRegister() && mi->getOperand(1).isUse() &&
mi->getOperand(2).isImm() && "Malformed extract_subreg");
unsigned SuperReg = mi->getOperand(1).getReg();
unsigned SubIdx = mi->getOperand(2).getImm();
assert(MRegisterInfo::isPhysicalRegister(SuperReg) &&
"Extract supperg source must be a physical register");
unsigned SrcReg = MRI.getSubReg(SuperReg, SubIdx);
unsigned DstReg = mi->getOperand(0).getReg();
DOUT << "subreg: CONVERTING: " << *mi;
if (SrcReg != DstReg) {
const TargetRegisterClass *TRC = 0;
if (MRegisterInfo::isPhysicalRegister(DstReg)) {
TRC = getPhysicalRegisterRegClass(MRI, DstReg);
} else {
TRC = MF.getSSARegMap()->getRegClass(DstReg);
}
assert(TRC == getPhysicalRegisterRegClass(MRI, SrcReg) &&
"Extract subreg and Dst must be of same register class");
MRI.copyRegToReg(*mbbi, mi, DstReg, SrcReg, TRC);
MachineBasicBlock::iterator dmi = mi;
DOUT << "subreg: " << *(--dmi);
}
DOUT << "\n";
mbbi->erase(mi);
MadeChange = true;
} else if (mi->getOpcode() == TargetInstrInfo::INSERT_SUBREG) {
unsigned DstReg = 0;
unsigned SrcReg = 0;
unsigned InsReg = 0;
unsigned SubIdx = 0;
// If only have 3 operands, then the source superreg is undef
// and we can supress the copy from the undef value
if (mi->getNumOperands() == 3) {
assert((mi->getOperand(0).isRegister() && mi->getOperand(0).isDef()) &&
(mi->getOperand(1).isRegister() && mi->getOperand(1).isUse()) &&
mi->getOperand(2).isImm() && "Invalid extract_subreg");
DstReg = mi->getOperand(0).getReg();
SrcReg = DstReg;
InsReg = mi->getOperand(1).getReg();
SubIdx = mi->getOperand(2).getImm();
} else if (mi->getNumOperands() == 4) {
assert((mi->getOperand(0).isRegister() && mi->getOperand(0).isDef()) &&
(mi->getOperand(1).isRegister() && mi->getOperand(1).isUse()) &&
(mi->getOperand(2).isRegister() && mi->getOperand(2).isUse()) &&
mi->getOperand(3).isImm() && "Invalid extract_subreg");
DstReg = mi->getOperand(0).getReg();
SrcReg = mi->getOperand(1).getReg();
InsReg = mi->getOperand(2).getReg();
SubIdx = mi->getOperand(3).getImm();
} else
assert(0 && "Malformed extract_subreg");
assert(SubIdx != 0 && "Invalid index for extract_subreg");
unsigned DstSubReg = MRI.getSubReg(DstReg, SubIdx);
assert(MRegisterInfo::isPhysicalRegister(SrcReg) &&
"Insert superreg source must be in a physical register");
assert(MRegisterInfo::isPhysicalRegister(DstReg) &&
"Insert destination must be in a physical register");
assert(MRegisterInfo::isPhysicalRegister(InsReg) &&
"Inserted value must be in a physical register");
DOUT << "subreg: CONVERTING: " << *mi;
// If the inserted register is already allocated into a subregister
// of the destination, we copy the subreg into the source
// However, this is only safe if the insert instruction is the kill
// of the source register
bool revCopyOrder = isSubRegOf(MRI, InsReg, DstReg);
if (revCopyOrder) {
if (mi->getOperand(1).isKill()) {
DstSubReg = MRI.getSubReg(SrcReg, SubIdx);
// Insert sub-register copy
const TargetRegisterClass *TRC1 = 0;
if (MRegisterInfo::isPhysicalRegister(InsReg)) {
TRC1 = getPhysicalRegisterRegClass(MRI, InsReg);
} else {
TRC1 = MF.getSSARegMap()->getRegClass(InsReg);
}
MRI.copyRegToReg(*mbbi, mi, DstSubReg, InsReg, TRC1);
MachineBasicBlock::iterator dmi = mi;
DOUT << "subreg: " << *(--dmi);
} else {
assert(0 && "Don't know how to convert this insert");
}
}
if (SrcReg != DstReg) {
// Insert super-register copy
const TargetRegisterClass *TRC0 = 0;
if (MRegisterInfo::isPhysicalRegister(DstReg)) {
TRC0 = getPhysicalRegisterRegClass(MRI, DstReg);
} else {
TRC0 = MF.getSSARegMap()->getRegClass(DstReg);
}
assert(TRC0 == getPhysicalRegisterRegClass(MRI, SrcReg) &&
"Insert superreg and Dst must be of same register class");
MRI.copyRegToReg(*mbbi, mi, DstReg, SrcReg, TRC0);
MachineBasicBlock::iterator dmi = mi;
DOUT << "subreg: " << *(--dmi);
}
if (!revCopyOrder && InsReg != DstSubReg) {
// Insert sub-register copy
const TargetRegisterClass *TRC1 = 0;
if (MRegisterInfo::isPhysicalRegister(InsReg)) {
TRC1 = getPhysicalRegisterRegClass(MRI, InsReg);
} else {
TRC1 = MF.getSSARegMap()->getRegClass(InsReg);
}
MRI.copyRegToReg(*mbbi, mi, DstSubReg, InsReg, TRC1);
MachineBasicBlock::iterator dmi = mi;
DOUT << "subreg: " << *(--dmi);
}
DOUT << "\n";
mbbi->erase(mi);
MadeChange = true;
mi != me;) {
MachineInstr *MI = mi++;
if (MI->getOpcode() == TargetInstrInfo::EXTRACT_SUBREG) {
MadeChange |= LowerExtract(MI);
} else if (MI->getOpcode() == TargetInstrInfo::INSERT_SUBREG) {
MadeChange |= LowerInsert(MI);
}
}
}