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llvm-mirror/lib/Target/Sparc/SparcInstrInfo.cpp
Vikram S. Adve ae84838162 Unify all constant evaluations that depend on register size 
in ConvertConstantToIntType.

llvm-svn: 7395
2003-07-29 19:59:23 +00:00

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//===-- SparcInstrInfo.cpp ------------------------------------------------===//
//
//===----------------------------------------------------------------------===//
#include "SparcInternals.h"
#include "SparcInstrSelectionSupport.h"
#include "llvm/CodeGen/InstrSelection.h"
#include "llvm/CodeGen/InstrSelectionSupport.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionInfo.h"
#include "llvm/CodeGen/MachineCodeForInstruction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Function.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "Config/stdlib.h"
static const uint32_t MAXLO = (1 << 10) - 1; // set bits set by %lo(*)
static const uint32_t MAXSIMM = (1 << 12) - 1; // set bits in simm13 field of OR
//---------------------------------------------------------------------------
// Function ConvertConstantToIntType
//
// Function to get the value of an integral constant in the form
// that must be put into the machine register. The specified constant is
// interpreted as (i.e., converted if necessary to) the specified destination
// type. The result is always returned as an uint64_t, since the representation
// of int64_t and uint64_t are identical. The argument can be any known const.
//
// isValidConstant is set to true if a valid constant was found.
//---------------------------------------------------------------------------
uint64_t
UltraSparcInstrInfo::ConvertConstantToIntType(const TargetMachine &target,
const Value *V,
const Type *destType,
bool &isValidConstant) const
{
isValidConstant = false;
uint64_t C = 0;
if (! destType->isIntegral() && ! isa<PointerType>(destType))
return C;
if (! isa<Constant>(V))
return C;
// ConstantPointerRef: no conversions needed: get value and return it
if (const ConstantPointerRef* CPR = dyn_cast<ConstantPointerRef>(V)) {
// A ConstantPointerRef is just a reference to GlobalValue.
isValidConstant = true; // may be overwritten by recursive call
return (CPR->isNullValue()? 0
: ConvertConstantToIntType(target, CPR->getValue(), destType,
isValidConstant));
}
// ConstantBool: no conversions needed: get value and return it
if (const ConstantBool *CB = dyn_cast<ConstantBool>(V)) {
isValidConstant = true;
return (uint64_t) CB->getValue();
}
// For other types of constants, some conversion may be needed.
// First, extract the constant operand according to its own type
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
switch(CE->getOpcode()) {
case Instruction::Cast: // recursively get the value as cast
C = ConvertConstantToIntType(target, CE->getOperand(0), CE->getType(),
isValidConstant);
break;
default: // not simplifying other ConstantExprs
break;
}
else if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
isValidConstant = true;
C = CI->getRawValue();
}
else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(V)) {
isValidConstant = true;
double fC = CFP->getValue();
C = (destType->isSigned()? (uint64_t) (int64_t) fC
: (uint64_t) fC);
}
// Now if a valid value was found, convert it to destType.
if (isValidConstant) {
unsigned opSize = target.getTargetData().getTypeSize(V->getType());
unsigned destSize = target.getTargetData().getTypeSize(destType);
uint64_t maskHi = (destSize < 8)? (1U << 8*destSize) - 1 : ~0;
assert(opSize <= 8 && destSize <= 8 && ">8-byte int type unexpected");
if (destType->isSigned()) {
if (opSize > destSize) // operand is larger than dest:
C = C & maskHi; // mask high bits
if (opSize > destSize ||
(opSize == destSize && ! V->getType()->isSigned()))
if (C & (1U << (8*destSize - 1)))
C = C | ~maskHi; // sign-extend from destSize to 64 bits
}
else {
if (opSize > destSize || (V->getType()->isSigned() && destSize < 8)) {
// operand is larger than dest,
// OR both are equal but smaller than the full register size
// AND operand is signed, so it may have extra sign bits:
// mask high bits
C = C & maskHi;
}
}
}
return C;
}
//----------------------------------------------------------------------------
// Function: CreateSETUWConst
//
// Set a 32-bit unsigned constant in the register `dest', using
// SETHI, OR in the worst case. This function correctly emulates
// the SETUW pseudo-op for SPARC v9 (if argument isSigned == false).
//
// The isSigned=true case is used to implement SETSW without duplicating code.
//
// Optimize some common cases:
// (1) Small value that fits in simm13 field of OR: don't need SETHI.
// (2) isSigned = true and C is a small negative signed value, i.e.,
// high bits are 1, and the remaining bits fit in simm13(OR).
//----------------------------------------------------------------------------
static inline void
CreateSETUWConst(const TargetMachine& target, uint32_t C,
Instruction* dest, std::vector<MachineInstr*>& mvec,
bool isSigned = false)
{
MachineInstr *miSETHI = NULL, *miOR = NULL;
// In order to get efficient code, we should not generate the SETHI if
// all high bits are 1 (i.e., this is a small signed value that fits in
// the simm13 field of OR). So we check for and handle that case specially.
// NOTE: The value C = 0x80000000 is bad: sC < 0 *and* -sC < 0.
// In fact, sC == -sC, so we have to check for this explicitly.
int32_t sC = (int32_t) C;
bool smallNegValue =isSigned && sC < 0 && sC != -sC && -sC < (int32_t)MAXSIMM;
// Set the high 22 bits in dest if non-zero and simm13 field of OR not enough
if (!smallNegValue && (C & ~MAXLO) && C > MAXSIMM) {
miSETHI = BuildMI(V9::SETHI, 2).addZImm(C).addRegDef(dest);
miSETHI->setOperandHi32(0);
mvec.push_back(miSETHI);
}
// Set the low 10 or 12 bits in dest. This is necessary if no SETHI
// was generated, or if the low 10 bits are non-zero.
if (miSETHI==NULL || C & MAXLO) {
if (miSETHI) {
// unsigned value with high-order bits set using SETHI
miOR = BuildMI(V9::ORi,3).addReg(dest).addZImm(C).addRegDef(dest);
miOR->setOperandLo32(1);
} else {
// unsigned or small signed value that fits in simm13 field of OR
assert(smallNegValue || (C & ~MAXSIMM) == 0);
miOR = BuildMI(V9::ORi, 3).addMReg(target.getRegInfo()
.getZeroRegNum())
.addSImm(sC).addRegDef(dest);
}
mvec.push_back(miOR);
}
assert((miSETHI || miOR) && "Oops, no code was generated!");
}
//----------------------------------------------------------------------------
// Function: CreateSETSWConst
//
// Set a 32-bit signed constant in the register `dest', with sign-extension
// to 64 bits. This uses SETHI, OR, SRA in the worst case.
// This function correctly emulates the SETSW pseudo-op for SPARC v9.
//
// Optimize the same cases as SETUWConst, plus:
// (1) SRA is not needed for positive or small negative values.
//----------------------------------------------------------------------------
static inline void
CreateSETSWConst(const TargetMachine& target, int32_t C,
Instruction* dest, std::vector<MachineInstr*>& mvec)
{
// Set the low 32 bits of dest
CreateSETUWConst(target, (uint32_t) C, dest, mvec, /*isSigned*/true);
// Sign-extend to the high 32 bits if needed.
// NOTE: The value C = 0x80000000 is bad: -C == C and so -C is < MAXSIMM
if (C < 0 && (C == -C || -C > (int32_t) MAXSIMM))
mvec.push_back(BuildMI(V9::SRAi5,3).addReg(dest).addZImm(0).addRegDef(dest));
}
//----------------------------------------------------------------------------
// Function: CreateSETXConst
//
// Set a 64-bit signed or unsigned constant in the register `dest'.
// Use SETUWConst for each 32 bit word, plus a left-shift-by-32 in between.
// This function correctly emulates the SETX pseudo-op for SPARC v9.
//
// Optimize the same cases as SETUWConst for each 32 bit word.
//----------------------------------------------------------------------------
static inline void
CreateSETXConst(const TargetMachine& target, uint64_t C,
Instruction* tmpReg, Instruction* dest,
std::vector<MachineInstr*>& mvec)
{
assert(C > (unsigned int) ~0 && "Use SETUW/SETSW for 32-bit values!");
MachineInstr* MI;
// Code to set the upper 32 bits of the value in register `tmpReg'
CreateSETUWConst(target, (C >> 32), tmpReg, mvec);
// Shift tmpReg left by 32 bits
mvec.push_back(BuildMI(V9::SLLXi6, 3).addReg(tmpReg).addZImm(32)
.addRegDef(tmpReg));
// Code to set the low 32 bits of the value in register `dest'
CreateSETUWConst(target, C, dest, mvec);
// dest = OR(tmpReg, dest)
mvec.push_back(BuildMI(V9::ORr,3).addReg(dest).addReg(tmpReg).addRegDef(dest));
}
//----------------------------------------------------------------------------
// Function: CreateSETUWLabel
//
// Set a 32-bit constant (given by a symbolic label) in the register `dest'.
//----------------------------------------------------------------------------
static inline void
CreateSETUWLabel(const TargetMachine& target, Value* val,
Instruction* dest, std::vector<MachineInstr*>& mvec)
{
MachineInstr* MI;
// Set the high 22 bits in dest
MI = BuildMI(V9::SETHI, 2).addReg(val).addRegDef(dest);
MI->setOperandHi32(0);
mvec.push_back(MI);
// Set the low 10 bits in dest
MI = BuildMI(V9::ORr, 3).addReg(dest).addReg(val).addRegDef(dest);
MI->setOperandLo32(1);
mvec.push_back(MI);
}
//----------------------------------------------------------------------------
// Function: CreateSETXLabel
//
// Set a 64-bit constant (given by a symbolic label) in the register `dest'.
//----------------------------------------------------------------------------
static inline void
CreateSETXLabel(const TargetMachine& target,
Value* val, Instruction* tmpReg, Instruction* dest,
std::vector<MachineInstr*>& mvec)
{
assert(isa<Constant>(val) || isa<GlobalValue>(val) &&
"I only know about constant values and global addresses");
MachineInstr* MI;
MI = BuildMI(V9::SETHI, 2).addPCDisp(val).addRegDef(tmpReg);
MI->setOperandHi64(0);
mvec.push_back(MI);
MI = BuildMI(V9::ORi, 3).addReg(tmpReg).addPCDisp(val).addRegDef(tmpReg);
MI->setOperandLo64(1);
mvec.push_back(MI);
mvec.push_back(BuildMI(V9::SLLXi6, 3).addReg(tmpReg).addZImm(32)
.addRegDef(tmpReg));
MI = BuildMI(V9::SETHI, 2).addPCDisp(val).addRegDef(dest);
MI->setOperandHi32(0);
mvec.push_back(MI);
MI = BuildMI(V9::ORr, 3).addReg(dest).addReg(tmpReg).addRegDef(dest);
mvec.push_back(MI);
MI = BuildMI(V9::ORi, 3).addReg(dest).addPCDisp(val).addRegDef(dest);
MI->setOperandLo32(1);
mvec.push_back(MI);
}
//----------------------------------------------------------------------------
// Function: CreateUIntSetInstruction
//
// Create code to Set an unsigned constant in the register `dest'.
// Uses CreateSETUWConst, CreateSETSWConst or CreateSETXConst as needed.
// CreateSETSWConst is an optimization for the case that the unsigned value
// has all ones in the 33 high bits (so that sign-extension sets them all).
//----------------------------------------------------------------------------
static inline void
CreateUIntSetInstruction(const TargetMachine& target,
uint64_t C, Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi)
{
static const uint64_t lo32 = (uint32_t) ~0;
if (C <= lo32) // High 32 bits are 0. Set low 32 bits.
CreateSETUWConst(target, (uint32_t) C, dest, mvec);
else if ((C & ~lo32) == ~lo32 && (C & (1U << 31))) {
// All high 33 (not 32) bits are 1s: sign-extension will take care
// of high 32 bits, so use the sequence for signed int
CreateSETSWConst(target, (int32_t) C, dest, mvec);
} else if (C > lo32) {
// C does not fit in 32 bits
TmpInstruction* tmpReg = new TmpInstruction(mcfi, Type::IntTy);
CreateSETXConst(target, C, tmpReg, dest, mvec);
}
}
//----------------------------------------------------------------------------
// Function: CreateIntSetInstruction
//
// Create code to Set a signed constant in the register `dest'.
// Really the same as CreateUIntSetInstruction.
//----------------------------------------------------------------------------
static inline void
CreateIntSetInstruction(const TargetMachine& target,
int64_t C, Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi)
{
CreateUIntSetInstruction(target, (uint64_t) C, dest, mvec, mcfi);
}
//---------------------------------------------------------------------------
// Create a table of LLVM opcode -> max. immediate constant likely to
// be usable for that operation.
//---------------------------------------------------------------------------
// Entry == 0 ==> no immediate constant field exists at all.
// Entry > 0 ==> abs(immediate constant) <= Entry
//
std::vector<int> MaxConstantsTable(Instruction::OtherOpsEnd);
static int
MaxConstantForInstr(unsigned llvmOpCode)
{
int modelOpCode = -1;
if (llvmOpCode >= Instruction::BinaryOpsBegin &&
llvmOpCode < Instruction::BinaryOpsEnd)
modelOpCode = V9::ADDi;
else
switch(llvmOpCode) {
case Instruction::Ret: modelOpCode = V9::JMPLCALLi; break;
case Instruction::Malloc:
case Instruction::Alloca:
case Instruction::GetElementPtr:
case Instruction::PHINode:
case Instruction::Cast:
case Instruction::Call: modelOpCode = V9::ADDi; break;
case Instruction::Shl:
case Instruction::Shr: modelOpCode = V9::SLLXi6; break;
default: break;
};
return (modelOpCode < 0)? 0: SparcMachineInstrDesc[modelOpCode].maxImmedConst;
}
static void
InitializeMaxConstantsTable()
{
unsigned op;
assert(MaxConstantsTable.size() == Instruction::OtherOpsEnd &&
"assignments below will be illegal!");
for (op = Instruction::TermOpsBegin; op < Instruction::TermOpsEnd; ++op)
MaxConstantsTable[op] = MaxConstantForInstr(op);
for (op = Instruction::BinaryOpsBegin; op < Instruction::BinaryOpsEnd; ++op)
MaxConstantsTable[op] = MaxConstantForInstr(op);
for (op = Instruction::MemoryOpsBegin; op < Instruction::MemoryOpsEnd; ++op)
MaxConstantsTable[op] = MaxConstantForInstr(op);
for (op = Instruction::OtherOpsBegin; op < Instruction::OtherOpsEnd; ++op)
MaxConstantsTable[op] = MaxConstantForInstr(op);
}
//---------------------------------------------------------------------------
// class UltraSparcInstrInfo
//
// Purpose:
// Information about individual instructions.
// Most information is stored in the SparcMachineInstrDesc array above.
// Other information is computed on demand, and most such functions
// default to member functions in base class TargetInstrInfo.
//---------------------------------------------------------------------------
/*ctor*/
UltraSparcInstrInfo::UltraSparcInstrInfo()
: TargetInstrInfo(SparcMachineInstrDesc,
/*descSize = */ V9::NUM_TOTAL_OPCODES,
/*numRealOpCodes = */ V9::NUM_REAL_OPCODES)
{
InitializeMaxConstantsTable();
}
bool
UltraSparcInstrInfo::ConstantMayNotFitInImmedField(const Constant* CV,
const Instruction* I) const
{
if (I->getOpcode() >= MaxConstantsTable.size()) // user-defined op (or bug!)
return true;
if (isa<ConstantPointerNull>(CV)) // can always use %g0
return false;
if (const ConstantInt* CI = dyn_cast<ConstantInt>(CV))
return labs((int64_t)CI->getRawValue()) > MaxConstantsTable[I->getOpcode()];
if (isa<ConstantBool>(CV))
return 1 > MaxConstantsTable[I->getOpcode()];
return true;
}
//
// Create an instruction sequence to put the constant `val' into
// the virtual register `dest'. `val' may be a Constant or a
// GlobalValue, viz., the constant address of a global variable or function.
// The generated instructions are returned in `mvec'.
// Any temp. registers (TmpInstruction) created are recorded in mcfi.
// Any stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateCodeToLoadConst(const TargetMachine& target,
Function* F,
Value* val,
Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
assert(isa<Constant>(val) || isa<GlobalValue>(val) &&
"I only know about constant values and global addresses");
// Use a "set" instruction for known constants or symbolic constants (labels)
// that can go in an integer reg.
// We have to use a "load" instruction for all other constants,
// in particular, floating point constants.
//
const Type* valType = val->getType();
// A ConstantPointerRef is just a reference to GlobalValue.
while (isa<ConstantPointerRef>(val))
val = cast<ConstantPointerRef>(val)->getValue();
if (isa<GlobalValue>(val)) {
TmpInstruction* tmpReg =
new TmpInstruction(mcfi, PointerType::get(val->getType()), val);
CreateSETXLabel(target, val, tmpReg, dest, mvec);
return;
}
bool isValid;
uint64_t C = ConvertConstantToIntType(target, val, dest->getType(), isValid);
if (isValid) {
if (dest->getType()->isSigned())
CreateUIntSetInstruction(target, C, dest, mvec, mcfi);
else
CreateIntSetInstruction(target, (int64_t) C, dest, mvec, mcfi);
} else {
// Make an instruction sequence to load the constant, viz:
// SETX <addr-of-constant>, tmpReg, addrReg
// LOAD /*addr*/ addrReg, /*offset*/ 0, dest
// First, create a tmp register to be used by the SETX sequence.
TmpInstruction* tmpReg =
new TmpInstruction(mcfi, PointerType::get(val->getType()), val);
// Create another TmpInstruction for the address register
TmpInstruction* addrReg =
new TmpInstruction(mcfi, PointerType::get(val->getType()), val);
// Put the address (a symbolic name) into a register
CreateSETXLabel(target, val, tmpReg, addrReg, mvec);
// Generate the load instruction
int64_t zeroOffset = 0; // to avoid ambiguity with (Value*) 0
unsigned Opcode = ChooseLoadInstruction(val->getType());
Opcode = convertOpcodeFromRegToImm(Opcode);
mvec.push_back(BuildMI(Opcode, 3).addReg(addrReg).
addSImm(zeroOffset).addRegDef(dest));
// Make sure constant is emitted to constant pool in assembly code.
MachineFunction::get(F).getInfo()->addToConstantPool(cast<Constant>(val));
}
}
// Create an instruction sequence to copy an integer register `val'
// to a floating point register `dest' by copying to memory and back.
// val must be an integral type. dest must be a Float or Double.
// The generated instructions are returned in `mvec'.
// Any temp. registers (TmpInstruction) created are recorded in mcfi.
// Any stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateCodeToCopyIntToFloat(const TargetMachine& target,
Function* F,
Value* val,
Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
assert((val->getType()->isIntegral() || isa<PointerType>(val->getType()))
&& "Source type must be integral (integer or bool) or pointer");
assert(dest->getType()->isFloatingPoint()
&& "Dest type must be float/double");
// Get a stack slot to use for the copy
int offset = MachineFunction::get(F).getInfo()->allocateLocalVar(val);
// Get the size of the source value being copied.
size_t srcSize = target.getTargetData().getTypeSize(val->getType());
// Store instruction stores `val' to [%fp+offset].
// The store and load opCodes are based on the size of the source value.
// If the value is smaller than 32 bits, we must sign- or zero-extend it
// to 32 bits since the load-float will load 32 bits.
// Note that the store instruction is the same for signed and unsigned ints.
const Type* storeType = (srcSize <= 4)? Type::IntTy : Type::LongTy;
Value* storeVal = val;
if (srcSize < target.getTargetData().getTypeSize(Type::FloatTy)) {
// sign- or zero-extend respectively
storeVal = new TmpInstruction(mcfi, storeType, val);
if (val->getType()->isSigned())
CreateSignExtensionInstructions(target, F, val, storeVal, 8*srcSize,
mvec, mcfi);
else
CreateZeroExtensionInstructions(target, F, val, storeVal, 8*srcSize,
mvec, mcfi);
}
unsigned FPReg = target.getRegInfo().getFramePointer();
unsigned StoreOpcode = ChooseStoreInstruction(storeType);
StoreOpcode = convertOpcodeFromRegToImm(StoreOpcode);
mvec.push_back(BuildMI(StoreOpcode, 3)
.addReg(storeVal).addMReg(FPReg).addSImm(offset));
// Load instruction loads [%fp+offset] to `dest'.
// The type of the load opCode is the floating point type that matches the
// stored type in size:
// On SparcV9: float for int or smaller, double for long.
//
const Type* loadType = (srcSize <= 4)? Type::FloatTy : Type::DoubleTy;
unsigned LoadOpcode = ChooseLoadInstruction(loadType);
LoadOpcode = convertOpcodeFromRegToImm(LoadOpcode);
mvec.push_back(BuildMI(LoadOpcode, 3)
.addMReg(FPReg).addSImm(offset).addRegDef(dest));
}
// Similarly, create an instruction sequence to copy an FP register
// `val' to an integer register `dest' by copying to memory and back.
// The generated instructions are returned in `mvec'.
// Any temp. virtual registers (TmpInstruction) created are recorded in mcfi.
// Temporary stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateCodeToCopyFloatToInt(const TargetMachine& target,
Function* F,
Value* val,
Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
const Type* opTy = val->getType();
const Type* destTy = dest->getType();
assert(opTy->isFloatingPoint() && "Source type must be float/double");
assert((destTy->isIntegral() || isa<PointerType>(destTy))
&& "Dest type must be integer, bool or pointer");
// FIXME: For now, we allocate permanent space because the stack frame
// manager does not allow locals to be allocated (e.g., for alloca) after
// a temp is allocated!
//
int offset = MachineFunction::get(F).getInfo()->allocateLocalVar(val);
unsigned FPReg = target.getRegInfo().getFramePointer();
// Store instruction stores `val' to [%fp+offset].
// The store opCode is based only the source value being copied.
//
unsigned StoreOpcode = ChooseStoreInstruction(opTy);
StoreOpcode = convertOpcodeFromRegToImm(StoreOpcode);
mvec.push_back(BuildMI(StoreOpcode, 3)
.addReg(val).addMReg(FPReg).addSImm(offset));
// Load instruction loads [%fp+offset] to `dest'.
// The type of the load opCode is the integer type that matches the
// source type in size:
// On SparcV9: int for float, long for double.
// Note that we *must* use signed loads even for unsigned dest types, to
// ensure correct sign-extension for UByte, UShort or UInt:
//
const Type* loadTy = (opTy == Type::FloatTy)? Type::IntTy : Type::LongTy;
unsigned LoadOpcode = ChooseLoadInstruction(loadTy);
LoadOpcode = convertOpcodeFromRegToImm(LoadOpcode);
mvec.push_back(BuildMI(LoadOpcode, 3).addMReg(FPReg)
.addSImm(offset).addRegDef(dest));
}
// Create instruction(s) to copy src to dest, for arbitrary types
// The generated instructions are returned in `mvec'.
// Any temp. registers (TmpInstruction) created are recorded in mcfi.
// Any stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateCopyInstructionsByType(const TargetMachine& target,
Function *F,
Value* src,
Instruction* dest,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
bool loadConstantToReg = false;
const Type* resultType = dest->getType();
MachineOpCode opCode = ChooseAddInstructionByType(resultType);
if (opCode == V9::INVALID_OPCODE) {
assert(0 && "Unsupported result type in CreateCopyInstructionsByType()");
return;
}
// if `src' is a constant that doesn't fit in the immed field or if it is
// a global variable (i.e., a constant address), generate a load
// instruction instead of an add
//
if (isa<Constant>(src)) {
unsigned int machineRegNum;
int64_t immedValue;
MachineOperand::MachineOperandType opType =
ChooseRegOrImmed(src, opCode, target, /*canUseImmed*/ true,
machineRegNum, immedValue);
if (opType == MachineOperand::MO_VirtualRegister)
loadConstantToReg = true;
}
else if (isa<GlobalValue>(src))
loadConstantToReg = true;
if (loadConstantToReg) {
// `src' is constant and cannot fit in immed field for the ADD
// Insert instructions to "load" the constant into a register
target.getInstrInfo().CreateCodeToLoadConst(target, F, src, dest,
mvec, mcfi);
} else {
// Create a reg-to-reg copy instruction for the given type:
// -- For FP values, create a FMOVS or FMOVD instruction
// -- For non-FP values, create an add-with-0 instruction (opCode as above)
// Make `src' the second operand, in case it is a small constant!
//
MachineInstr* MI;
if (resultType->isFloatingPoint())
MI = (BuildMI(resultType == Type::FloatTy? V9::FMOVS : V9::FMOVD, 2)
.addReg(src).addRegDef(dest));
else {
const Type* Ty =isa<PointerType>(resultType)? Type::ULongTy :resultType;
MI = (BuildMI(opCode, 3)
.addSImm((int64_t) 0).addReg(src).addRegDef(dest));
}
mvec.push_back(MI);
}
}
// Helper function for sign-extension and zero-extension.
// For SPARC v9, we sign-extend the given operand using SLL; SRA/SRL.
inline void
CreateBitExtensionInstructions(bool signExtend,
const TargetMachine& target,
Function* F,
Value* srcVal,
Value* destVal,
unsigned int numLowBits,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi)
{
MachineInstr* M;
assert(numLowBits <= 32 && "Otherwise, nothing should be done here!");
if (numLowBits < 32) {
// SLL is needed since operand size is < 32 bits.
TmpInstruction *tmpI = new TmpInstruction(mcfi, destVal->getType(),
srcVal, destVal, "make32");
mvec.push_back(BuildMI(V9::SLLXi6, 3).addReg(srcVal)
.addZImm(32-numLowBits).addRegDef(tmpI));
srcVal = tmpI;
}
mvec.push_back(BuildMI(signExtend? V9::SRAi5 : V9::SRLi5, 3)
.addReg(srcVal).addZImm(32-numLowBits).addRegDef(destVal));
}
// Create instruction sequence to produce a sign-extended register value
// from an arbitrary-sized integer value (sized in bits, not bytes).
// The generated instructions are returned in `mvec'.
// Any temp. registers (TmpInstruction) created are recorded in mcfi.
// Any stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateSignExtensionInstructions(
const TargetMachine& target,
Function* F,
Value* srcVal,
Value* destVal,
unsigned int numLowBits,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
CreateBitExtensionInstructions(/*signExtend*/ true, target, F, srcVal,
destVal, numLowBits, mvec, mcfi);
}
// Create instruction sequence to produce a zero-extended register value
// from an arbitrary-sized integer value (sized in bits, not bytes).
// For SPARC v9, we sign-extend the given operand using SLL; SRL.
// The generated instructions are returned in `mvec'.
// Any temp. registers (TmpInstruction) created are recorded in mcfi.
// Any stack space required is allocated via MachineFunction.
//
void
UltraSparcInstrInfo::CreateZeroExtensionInstructions(
const TargetMachine& target,
Function* F,
Value* srcVal,
Value* destVal,
unsigned int numLowBits,
std::vector<MachineInstr*>& mvec,
MachineCodeForInstruction& mcfi) const
{
CreateBitExtensionInstructions(/*signExtend*/ false, target, F, srcVal,
destVal, numLowBits, mvec, mcfi);
}
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