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Add a version of ChooseRegOrImmed to handle numerical constants 

introduced by InstrSelection.

llvm-svn: 3735
This commit is contained in:
Vikram S. Adve 2002-09-16 15:15:57 +00:00
parent 4d66e9973f
commit 03710d247d
1 changed files with 119 additions and 84 deletions
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203
llvm/lib/CodeGen/InstrSelection/InstrSelectionSupport.cpp
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@ -312,6 +312,36 @@ Set3OperandsFromInstr(MachineInstr* minstr,
}
MachineOperand::MachineOperandType
ChooseRegOrImmed(int64_t intValue,
bool isSigned,
MachineOpCode opCode,
const TargetMachine& target,
bool canUseImmed,
unsigned int& getMachineRegNum,
int64_t& getImmedValue)
{
MachineOperand::MachineOperandType opType=MachineOperand::MO_VirtualRegister;
getMachineRegNum = 0;
getImmedValue = 0;
if (canUseImmed &&
target.getInstrInfo().constantFitsInImmedField(opCode, intValue))
{
opType = isSigned? MachineOperand::MO_SignExtendedImmed
: MachineOperand::MO_UnextendedImmed;
getImmedValue = intValue;
}
else if (intValue == 0 && target.getRegInfo().getZeroRegNum() >= 0)
{
opType = MachineOperand::MO_MachineRegister;
getMachineRegNum = target.getRegInfo().getZeroRegNum();
}
return opType;
}
MachineOperand::MachineOperandType
ChooseRegOrImmed(Value* val,
MachineOpCode opCode,
@ -320,34 +350,16 @@ ChooseRegOrImmed(Value* val,
unsigned int& getMachineRegNum,
int64_t& getImmedValue)
{
MachineOperand::MachineOperandType opType =
MachineOperand::MO_VirtualRegister;
getMachineRegNum = 0;
getImmedValue = 0;
// Check for the common case first: argument is not constant
//
// To use reg or immed, constant needs to be integer, bool, or a NULL pointer
Constant *CPV = dyn_cast<Constant>(val);
if (!CPV) return opType;
if (CPV == NULL ||
(! CPV->getType()->isIntegral() &&
! (isa<PointerType>(CPV->getType()) && CPV->isNullValue())))
return MachineOperand::MO_VirtualRegister;
if (ConstantBool *CPB = dyn_cast<ConstantBool>(CPV))
{
if (!CPB->getValue() && target.getRegInfo().getZeroRegNum() >= 0)
{
getMachineRegNum = target.getRegInfo().getZeroRegNum();
return MachineOperand::MO_MachineRegister;
}
getImmedValue = 1;
return MachineOperand::MO_SignExtendedImmed;
}
// Otherwise it needs to be an integer or a NULL pointer
if (! CPV->getType()->isInteger() &&
! (isa<PointerType>(CPV->getType()) &&
CPV->isNullValue()))
return opType;
// Now get the constant value and check if it fits in the IMMED field.
// Take advantage of the fact that the max unsigned value will rarely
// fit into any IMMED field and ignore that case (i.e., cast smaller
@ -355,35 +367,22 @@ ChooseRegOrImmed(Value* val,
//
int64_t intValue;
if (isa<PointerType>(CPV->getType()))
{
intValue = 0;
}
intValue = 0; // We checked above that it is NULL
else if (ConstantBool* CB = dyn_cast<ConstantBool>(CPV))
intValue = (int64_t) CB->getValue();
else if (CPV->getType()->isSigned())
{
intValue = cast<ConstantSInt>(CPV)->getValue();
}
intValue = cast<ConstantSInt>(CPV)->getValue();
else
{
assert(CPV->getType()->isUnsigned() && "Not pointer, bool, or integer?");
uint64_t V = cast<ConstantUInt>(CPV)->getValue();
if (V >= INT64_MAX) return opType;
intValue = (int64_t)V;
if (V >= INT64_MAX) return MachineOperand::MO_VirtualRegister;
intValue = (int64_t) V;
}
if (intValue == 0 && target.getRegInfo().getZeroRegNum() >= 0)
{
opType = MachineOperand::MO_MachineRegister;
getMachineRegNum = target.getRegInfo().getZeroRegNum();
}
else if (canUseImmed &&
target.getInstrInfo().constantFitsInImmedField(opCode, intValue))
{
opType = CPV->getType()->isSigned()
? MachineOperand::MO_SignExtendedImmed
: MachineOperand::MO_UnextendedImmed;
getImmedValue = intValue;
}
return opType;
return ChooseRegOrImmed(intValue, CPV->getType()->isSigned(),
opCode, target, canUseImmed,
getMachineRegNum, getImmedValue);
}
@ -409,55 +408,91 @@ FixConstantOperandsForInstr(Instruction* vmInstr,
{
vector<MachineInstr*> loadConstVec;
const MachineInstrDescriptor& instrDesc =
target.getInstrInfo().getDescriptor(minstr->getOpCode());
MachineOpCode opCode = minstr->getOpCode();
const MachineInstrInfo& instrInfo = target.getInstrInfo();
const MachineInstrDescriptor& instrDesc = instrInfo.getDescriptor(opCode);
int immedPos = instrInfo.getImmedConstantPos(opCode);
Function *F = vmInstr->getParent()->getParent();
for (unsigned op=0; op < minstr->getNumOperands(); op++)
{
const MachineOperand& mop = minstr->getOperand(op);
// skip the result position (for efficiency below) and any other
// positions already marked as not a virtual register
if (instrDesc.resultPos == (int) op ||
mop.getOperandType() != MachineOperand::MO_VirtualRegister ||
mop.getVRegValue() == NULL)
{
continue;
}
Value* opValue = mop.getVRegValue();
// Skip the result position, preallocated machine registers, or operands
// that cannot be constants (CC regs or PC-relative displacements)
if (instrDesc.resultPos == (int) op ||
mop.getOperandType() == MachineOperand::MO_MachineRegister ||
mop.getOperandType() == MachineOperand::MO_CCRegister ||
mop.getOperandType() == MachineOperand::MO_PCRelativeDisp)
continue;
bool constantThatMustBeLoaded = false;
if (Constant *opConst = dyn_cast<Constant>(opValue))
unsigned int machineRegNum = 0;
int64_t immedValue = 0;
Value* opValue = NULL;
MachineOperand::MachineOperandType opType =
MachineOperand::MO_VirtualRegister;
// Operand may be a virtual register or a compile-time constant
if (mop.getOperandType() == MachineOperand::MO_VirtualRegister)
{
unsigned int machineRegNum;
int64_t immedValue;
MachineOperand::MachineOperandType opType =
ChooseRegOrImmed(opValue, minstr->getOpCode(), target,
(target.getInstrInfo().getImmedConstantPos(minstr->getOpCode()) == (int) op),
machineRegNum, immedValue);
if (opType == MachineOperand::MO_MachineRegister)
minstr->SetMachineOperandReg(op, machineRegNum);
else if (opType == MachineOperand::MO_VirtualRegister)
constantThatMustBeLoaded = true; // load is generated below
else
minstr->SetMachineOperandConst(op, opType, immedValue);
assert(mop.getVRegValue() != NULL);
opValue = mop.getVRegValue();
if (Constant *opConst = dyn_cast<Constant>(opValue))
{
opType = ChooseRegOrImmed(opConst, opCode, target,
(immedPos == (int)op), machineRegNum, immedValue);
if (opType == MachineOperand::MO_VirtualRegister)
constantThatMustBeLoaded = true;
}
}
if (constantThatMustBeLoaded || isa<GlobalValue>(opValue))
{ // opValue is a constant that must be explicitly loaded into a reg.
TmpInstruction* tmpReg = InsertCodeToLoadConstant(F, opValue,vmInstr,
loadConstVec,
target);
else
{
assert(mop.getOperandType() == MachineOperand::MO_SignExtendedImmed ||
mop.getOperandType() == MachineOperand::MO_UnextendedImmed);
bool isSigned = (mop.getOperandType() ==
MachineOperand::MO_SignExtendedImmed);
// Bit-selection flags indicate an instruction that is extracting
// bits from its operand so ignore this even if it is a big constant.
if (mop.opHiBits32() || mop.opLoBits32() ||
mop.opHiBits64() || mop.opLoBits64())
continue;
opType = ChooseRegOrImmed(mop.getImmedValue(), isSigned,
opCode, target, (immedPos == (int)op),
machineRegNum, immedValue);
if (opType == mop.getOperandType())
continue; // no change: this is the most common case
if (opType == MachineOperand::MO_VirtualRegister)
{
constantThatMustBeLoaded = true;
opValue = isSigned
? ConstantSInt::get(Type::LongTy, immedValue)
: ConstantUInt::get(Type::ULongTy, (uint64_t) immedValue);
}
}
if (opType == MachineOperand::MO_MachineRegister)
minstr->SetMachineOperandReg(op, machineRegNum);
else if (opType == MachineOperand::MO_SignExtendedImmed ||
opType == MachineOperand::MO_UnextendedImmed)
minstr->SetMachineOperandConst(op, opType, immedValue);
else if (constantThatMustBeLoaded ||
(opValue && isa<GlobalValue>(opValue)))
{ // opValue is a constant that must be explicitly loaded into a reg
assert(opValue);
TmpInstruction* tmpReg = InsertCodeToLoadConstant(F, opValue, vmInstr,
loadConstVec, target);
minstr->SetMachineOperandVal(op, MachineOperand::MO_VirtualRegister,
tmpReg);
}
}
//
// Also, check for implicit operands used by the machine instruction
// (no need to check those defined since they cannot be constants).
// These include:
@ -468,7 +503,7 @@ FixConstantOperandsForInstr(Instruction* vmInstr,
// have no immediate fields, so the constant always needs to be loaded
// into a register.
//
bool isCall = target.getInstrInfo().isCall(minstr->getOpCode());
bool isCall = instrInfo.isCall(opCode);
unsigned lastCallArgNum = 0; // unused if not a call
CallArgsDescriptor* argDesc = NULL; // unused if not a call
if (isCall)