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llvm-mirror/lib/CodeGen/MachineInstr.cpp
Dan Gohman 5bfc2416fe Factor out LiveIntervalAnalysis' code to determine whether an instruction 
is trivially rematerializable and integrate it into
TargetInstrInfo::isTriviallyReMaterializable. This way, all places that
need to know whether an instruction is rematerializable will get the
same answer.

This enables the useful parts of the aggressive-remat option by
default -- using AliasAnalysis to determine whether a memory location
is invariant, and removes the questionable parts -- rematting operations
with virtual register inputs that may not be live everywhere.

llvm-svn: 83687
2009-10-09 23:27:56 +00:00

1210 lines
42 KiB
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//===-- lib/CodeGen/MachineInstr.cpp --------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Methods common to all machine instructions.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/Constants.h"
#include "llvm/InlineAsm.h"
#include "llvm/Value.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetInstrDesc.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LeakDetector.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/FoldingSet.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// MachineOperand Implementation
//===----------------------------------------------------------------------===//
/// AddRegOperandToRegInfo - Add this register operand to the specified
/// MachineRegisterInfo. If it is null, then the next/prev fields should be
/// explicitly nulled out.
void MachineOperand::AddRegOperandToRegInfo(MachineRegisterInfo *RegInfo) {
assert(isReg() && "Can only add reg operand to use lists");
// If the reginfo pointer is null, just explicitly null out or next/prev
// pointers, to ensure they are not garbage.
if (RegInfo == 0) {
Contents.Reg.Prev = 0;
Contents.Reg.Next = 0;
return;
}
// Otherwise, add this operand to the head of the registers use/def list.
MachineOperand **Head = &RegInfo->getRegUseDefListHead(getReg());
// For SSA values, we prefer to keep the definition at the start of the list.
// we do this by skipping over the definition if it is at the head of the
// list.
if (*Head && (*Head)->isDef())
Head = &(*Head)->Contents.Reg.Next;
Contents.Reg.Next = *Head;
if (Contents.Reg.Next) {
assert(getReg() == Contents.Reg.Next->getReg() &&
"Different regs on the same list!");
Contents.Reg.Next->Contents.Reg.Prev = &Contents.Reg.Next;
}
Contents.Reg.Prev = Head;
*Head = this;
}
/// RemoveRegOperandFromRegInfo - Remove this register operand from the
/// MachineRegisterInfo it is linked with.
void MachineOperand::RemoveRegOperandFromRegInfo() {
assert(isOnRegUseList() && "Reg operand is not on a use list");
// Unlink this from the doubly linked list of operands.
MachineOperand *NextOp = Contents.Reg.Next;
*Contents.Reg.Prev = NextOp;
if (NextOp) {
assert(NextOp->getReg() == getReg() && "Corrupt reg use/def chain!");
NextOp->Contents.Reg.Prev = Contents.Reg.Prev;
}
Contents.Reg.Prev = 0;
Contents.Reg.Next = 0;
}
void MachineOperand::setReg(unsigned Reg) {
if (getReg() == Reg) return; // No change.
// Otherwise, we have to change the register. If this operand is embedded
// into a machine function, we need to update the old and new register's
// use/def lists.
if (MachineInstr *MI = getParent())
if (MachineBasicBlock *MBB = MI->getParent())
if (MachineFunction *MF = MBB->getParent()) {
RemoveRegOperandFromRegInfo();
Contents.Reg.RegNo = Reg;
AddRegOperandToRegInfo(&MF->getRegInfo());
return;
}
// Otherwise, just change the register, no problem. :)
Contents.Reg.RegNo = Reg;
}
/// ChangeToImmediate - Replace this operand with a new immediate operand of
/// the specified value. If an operand is known to be an immediate already,
/// the setImm method should be used.
void MachineOperand::ChangeToImmediate(int64_t ImmVal) {
// If this operand is currently a register operand, and if this is in a
// function, deregister the operand from the register's use/def list.
if (isReg() && getParent() && getParent()->getParent() &&
getParent()->getParent()->getParent())
RemoveRegOperandFromRegInfo();
OpKind = MO_Immediate;
Contents.ImmVal = ImmVal;
}
/// ChangeToRegister - Replace this operand with a new register operand of
/// the specified value. If an operand is known to be an register already,
/// the setReg method should be used.
void MachineOperand::ChangeToRegister(unsigned Reg, bool isDef, bool isImp,
bool isKill, bool isDead, bool isUndef) {
// If this operand is already a register operand, use setReg to update the
// register's use/def lists.
if (isReg()) {
assert(!isEarlyClobber());
setReg(Reg);
} else {
// Otherwise, change this to a register and set the reg#.
OpKind = MO_Register;
Contents.Reg.RegNo = Reg;
// If this operand is embedded in a function, add the operand to the
// register's use/def list.
if (MachineInstr *MI = getParent())
if (MachineBasicBlock *MBB = MI->getParent())
if (MachineFunction *MF = MBB->getParent())
AddRegOperandToRegInfo(&MF->getRegInfo());
}
IsDef = isDef;
IsImp = isImp;
IsKill = isKill;
IsDead = isDead;
IsUndef = isUndef;
IsEarlyClobber = false;
SubReg = 0;
}
/// isIdenticalTo - Return true if this operand is identical to the specified
/// operand.
bool MachineOperand::isIdenticalTo(const MachineOperand &Other) const {
if (getType() != Other.getType() ||
getTargetFlags() != Other.getTargetFlags())
return false;
switch (getType()) {
default: llvm_unreachable("Unrecognized operand type");
case MachineOperand::MO_Register:
return getReg() == Other.getReg() && isDef() == Other.isDef() &&
getSubReg() == Other.getSubReg();
case MachineOperand::MO_Immediate:
return getImm() == Other.getImm();
case MachineOperand::MO_FPImmediate:
return getFPImm() == Other.getFPImm();
case MachineOperand::MO_MachineBasicBlock:
return getMBB() == Other.getMBB();
case MachineOperand::MO_FrameIndex:
return getIndex() == Other.getIndex();
case MachineOperand::MO_ConstantPoolIndex:
return getIndex() == Other.getIndex() && getOffset() == Other.getOffset();
case MachineOperand::MO_JumpTableIndex:
return getIndex() == Other.getIndex();
case MachineOperand::MO_GlobalAddress:
return getGlobal() == Other.getGlobal() && getOffset() == Other.getOffset();
case MachineOperand::MO_ExternalSymbol:
return !strcmp(getSymbolName(), Other.getSymbolName()) &&
getOffset() == Other.getOffset();
}
}
/// print - Print the specified machine operand.
///
void MachineOperand::print(raw_ostream &OS, const TargetMachine *TM) const {
switch (getType()) {
case MachineOperand::MO_Register:
if (getReg() == 0 || TargetRegisterInfo::isVirtualRegister(getReg())) {
OS << "%reg" << getReg();
} else {
// If the instruction is embedded into a basic block, we can find the
// target info for the instruction.
if (TM == 0)
if (const MachineInstr *MI = getParent())
if (const MachineBasicBlock *MBB = MI->getParent())
if (const MachineFunction *MF = MBB->getParent())
TM = &MF->getTarget();
if (TM)
OS << "%" << TM->getRegisterInfo()->get(getReg()).Name;
else
OS << "%mreg" << getReg();
}
if (getSubReg() != 0)
OS << ':' << getSubReg();
if (isDef() || isKill() || isDead() || isImplicit() || isUndef() ||
isEarlyClobber()) {
OS << '<';
bool NeedComma = false;
if (isImplicit()) {
if (NeedComma) OS << ',';
OS << (isDef() ? "imp-def" : "imp-use");
NeedComma = true;
} else if (isDef()) {
if (NeedComma) OS << ',';
if (isEarlyClobber())
OS << "earlyclobber,";
OS << "def";
NeedComma = true;
}
if (isKill() || isDead() || isUndef()) {
if (NeedComma) OS << ',';
if (isKill()) OS << "kill";
if (isDead()) OS << "dead";
if (isUndef()) {
if (isKill() || isDead())
OS << ',';
OS << "undef";
}
}
OS << '>';
}
break;
case MachineOperand::MO_Immediate:
OS << getImm();
break;
case MachineOperand::MO_FPImmediate:
if (getFPImm()->getType()->isFloatTy())
OS << getFPImm()->getValueAPF().convertToFloat();
else
OS << getFPImm()->getValueAPF().convertToDouble();
break;
case MachineOperand::MO_MachineBasicBlock:
OS << "mbb<"
<< ((Value*)getMBB()->getBasicBlock())->getName()
<< "," << (void*)getMBB() << '>';
break;
case MachineOperand::MO_FrameIndex:
OS << "<fi#" << getIndex() << '>';
break;
case MachineOperand::MO_ConstantPoolIndex:
OS << "<cp#" << getIndex();
if (getOffset()) OS << "+" << getOffset();
OS << '>';
break;
case MachineOperand::MO_JumpTableIndex:
OS << "<jt#" << getIndex() << '>';
break;
case MachineOperand::MO_GlobalAddress:
OS << "<ga:" << ((Value*)getGlobal())->getName();
if (getOffset()) OS << "+" << getOffset();
OS << '>';
break;
case MachineOperand::MO_ExternalSymbol:
OS << "<es:" << getSymbolName();
if (getOffset()) OS << "+" << getOffset();
OS << '>';
break;
default:
llvm_unreachable("Unrecognized operand type");
}
if (unsigned TF = getTargetFlags())
OS << "[TF=" << TF << ']';
}
//===----------------------------------------------------------------------===//
// MachineMemOperand Implementation
//===----------------------------------------------------------------------===//
MachineMemOperand::MachineMemOperand(const Value *v, unsigned int f,
int64_t o, uint64_t s, unsigned int a)
: Offset(o), Size(s), V(v),
Flags((f & 7) | ((Log2_32(a) + 1) << 3)) {
assert(getBaseAlignment() == a && "Alignment is not a power of 2!");
assert((isLoad() || isStore()) && "Not a load/store!");
}
/// Profile - Gather unique data for the object.
///
void MachineMemOperand::Profile(FoldingSetNodeID &ID) const {
ID.AddInteger(Offset);
ID.AddInteger(Size);
ID.AddPointer(V);
ID.AddInteger(Flags);
}
void MachineMemOperand::refineAlignment(const MachineMemOperand *MMO) {
// The Value and Offset may differ due to CSE. But the flags and size
// should be the same.
assert(MMO->getFlags() == getFlags() && "Flags mismatch!");
assert(MMO->getSize() == getSize() && "Size mismatch!");
if (MMO->getBaseAlignment() >= getBaseAlignment()) {
// Update the alignment value.
Flags = (Flags & 7) | ((Log2_32(MMO->getBaseAlignment()) + 1) << 3);
// Also update the base and offset, because the new alignment may
// not be applicable with the old ones.
V = MMO->getValue();
Offset = MMO->getOffset();
}
}
/// getAlignment - Return the minimum known alignment in bytes of the
/// actual memory reference.
uint64_t MachineMemOperand::getAlignment() const {
return MinAlign(getBaseAlignment(), getOffset());
}
raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineMemOperand &MMO) {
assert((MMO.isLoad() || MMO.isStore()) &&
"SV has to be a load, store or both.");
if (MMO.isVolatile())
OS << "Volatile ";
if (MMO.isLoad())
OS << "LD";
if (MMO.isStore())
OS << "ST";
OS << MMO.getSize();
// Print the address information.
OS << "[";
if (!MMO.getValue())
OS << "<unknown>";
else
WriteAsOperand(OS, MMO.getValue(), /*PrintType=*/false);
// If the alignment of the memory reference itself differs from the alignment
// of the base pointer, print the base alignment explicitly, next to the base
// pointer.
if (MMO.getBaseAlignment() != MMO.getAlignment())
OS << "(align=" << MMO.getBaseAlignment() << ")";
if (MMO.getOffset() != 0)
OS << "+" << MMO.getOffset();
OS << "]";
// Print the alignment of the reference.
if (MMO.getBaseAlignment() != MMO.getAlignment() ||
MMO.getBaseAlignment() != MMO.getSize())
OS << "(align=" << MMO.getAlignment() << ")";
return OS;
}
//===----------------------------------------------------------------------===//
// MachineInstr Implementation
//===----------------------------------------------------------------------===//
/// MachineInstr ctor - This constructor creates a dummy MachineInstr with
/// TID NULL and no operands.
MachineInstr::MachineInstr()
: TID(0), NumImplicitOps(0), MemRefs(0), MemRefsEnd(0),
Parent(0), debugLoc(DebugLoc::getUnknownLoc()) {
// Make sure that we get added to a machine basicblock
LeakDetector::addGarbageObject(this);
}
void MachineInstr::addImplicitDefUseOperands() {
if (TID->ImplicitDefs)
for (const unsigned *ImpDefs = TID->ImplicitDefs; *ImpDefs; ++ImpDefs)
addOperand(MachineOperand::CreateReg(*ImpDefs, true, true));
if (TID->ImplicitUses)
for (const unsigned *ImpUses = TID->ImplicitUses; *ImpUses; ++ImpUses)
addOperand(MachineOperand::CreateReg(*ImpUses, false, true));
}
/// MachineInstr ctor - This constructor create a MachineInstr and add the
/// implicit operands. It reserves space for number of operands specified by
/// TargetInstrDesc or the numOperands if it is not zero. (for
/// instructions with variable number of operands).
MachineInstr::MachineInstr(const TargetInstrDesc &tid, bool NoImp)
: TID(&tid), NumImplicitOps(0), MemRefs(0), MemRefsEnd(0), Parent(0),
debugLoc(DebugLoc::getUnknownLoc()) {
if (!NoImp && TID->getImplicitDefs())
for (const unsigned *ImpDefs = TID->getImplicitDefs(); *ImpDefs; ++ImpDefs)
NumImplicitOps++;
if (!NoImp && TID->getImplicitUses())
for (const unsigned *ImpUses = TID->getImplicitUses(); *ImpUses; ++ImpUses)
NumImplicitOps++;
Operands.reserve(NumImplicitOps + TID->getNumOperands());
if (!NoImp)
addImplicitDefUseOperands();
// Make sure that we get added to a machine basicblock
LeakDetector::addGarbageObject(this);
}
/// MachineInstr ctor - As above, but with a DebugLoc.
MachineInstr::MachineInstr(const TargetInstrDesc &tid, const DebugLoc dl,
bool NoImp)
: TID(&tid), NumImplicitOps(0), MemRefs(0), MemRefsEnd(0),
Parent(0), debugLoc(dl) {
if (!NoImp && TID->getImplicitDefs())
for (const unsigned *ImpDefs = TID->getImplicitDefs(); *ImpDefs; ++ImpDefs)
NumImplicitOps++;
if (!NoImp && TID->getImplicitUses())
for (const unsigned *ImpUses = TID->getImplicitUses(); *ImpUses; ++ImpUses)
NumImplicitOps++;
Operands.reserve(NumImplicitOps + TID->getNumOperands());
if (!NoImp)
addImplicitDefUseOperands();
// Make sure that we get added to a machine basicblock
LeakDetector::addGarbageObject(this);
}
/// MachineInstr ctor - Work exactly the same as the ctor two above, except
/// that the MachineInstr is created and added to the end of the specified
/// basic block.
///
MachineInstr::MachineInstr(MachineBasicBlock *MBB, const TargetInstrDesc &tid)
: TID(&tid), NumImplicitOps(0), MemRefs(0), MemRefsEnd(0), Parent(0),
debugLoc(DebugLoc::getUnknownLoc()) {
assert(MBB && "Cannot use inserting ctor with null basic block!");
if (TID->ImplicitDefs)
for (const unsigned *ImpDefs = TID->getImplicitDefs(); *ImpDefs; ++ImpDefs)
NumImplicitOps++;
if (TID->ImplicitUses)
for (const unsigned *ImpUses = TID->getImplicitUses(); *ImpUses; ++ImpUses)
NumImplicitOps++;
Operands.reserve(NumImplicitOps + TID->getNumOperands());
addImplicitDefUseOperands();
// Make sure that we get added to a machine basicblock
LeakDetector::addGarbageObject(this);
MBB->push_back(this); // Add instruction to end of basic block!
}
/// MachineInstr ctor - As above, but with a DebugLoc.
///
MachineInstr::MachineInstr(MachineBasicBlock *MBB, const DebugLoc dl,
const TargetInstrDesc &tid)
: TID(&tid), NumImplicitOps(0), MemRefs(0), MemRefsEnd(0),
Parent(0), debugLoc(dl) {
assert(MBB && "Cannot use inserting ctor with null basic block!");
if (TID->ImplicitDefs)
for (const unsigned *ImpDefs = TID->getImplicitDefs(); *ImpDefs; ++ImpDefs)
NumImplicitOps++;
if (TID->ImplicitUses)
for (const unsigned *ImpUses = TID->getImplicitUses(); *ImpUses; ++ImpUses)
NumImplicitOps++;
Operands.reserve(NumImplicitOps + TID->getNumOperands());
addImplicitDefUseOperands();
// Make sure that we get added to a machine basicblock
LeakDetector::addGarbageObject(this);
MBB->push_back(this); // Add instruction to end of basic block!
}
/// MachineInstr ctor - Copies MachineInstr arg exactly
///
MachineInstr::MachineInstr(MachineFunction &MF, const MachineInstr &MI)
: TID(&MI.getDesc()), NumImplicitOps(0),
MemRefs(MI.MemRefs), MemRefsEnd(MI.MemRefsEnd),
Parent(0), debugLoc(MI.getDebugLoc()) {
Operands.reserve(MI.getNumOperands());
// Add operands
for (unsigned i = 0; i != MI.getNumOperands(); ++i)
addOperand(MI.getOperand(i));
NumImplicitOps = MI.NumImplicitOps;
// Set parent to null.
Parent = 0;
LeakDetector::addGarbageObject(this);
}
MachineInstr::~MachineInstr() {
LeakDetector::removeGarbageObject(this);
#ifndef NDEBUG
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
assert(Operands[i].ParentMI == this && "ParentMI mismatch!");
assert((!Operands[i].isReg() || !Operands[i].isOnRegUseList()) &&
"Reg operand def/use list corrupted");
}
#endif
}
/// getRegInfo - If this instruction is embedded into a MachineFunction,
/// return the MachineRegisterInfo object for the current function, otherwise
/// return null.
MachineRegisterInfo *MachineInstr::getRegInfo() {
if (MachineBasicBlock *MBB = getParent())
return &MBB->getParent()->getRegInfo();
return 0;
}
/// RemoveRegOperandsFromUseLists - Unlink all of the register operands in
/// this instruction from their respective use lists. This requires that the
/// operands already be on their use lists.
void MachineInstr::RemoveRegOperandsFromUseLists() {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (Operands[i].isReg())
Operands[i].RemoveRegOperandFromRegInfo();
}
}
/// AddRegOperandsToUseLists - Add all of the register operands in
/// this instruction from their respective use lists. This requires that the
/// operands not be on their use lists yet.
void MachineInstr::AddRegOperandsToUseLists(MachineRegisterInfo &RegInfo) {
for (unsigned i = 0, e = Operands.size(); i != e; ++i) {
if (Operands[i].isReg())
Operands[i].AddRegOperandToRegInfo(&RegInfo);
}
}
/// addOperand - Add the specified operand to the instruction. If it is an
/// implicit operand, it is added to the end of the operand list. If it is
/// an explicit operand it is added at the end of the explicit operand list
/// (before the first implicit operand).
void MachineInstr::addOperand(const MachineOperand &Op) {
bool isImpReg = Op.isReg() && Op.isImplicit();
assert((isImpReg || !OperandsComplete()) &&
"Trying to add an operand to a machine instr that is already done!");
MachineRegisterInfo *RegInfo = getRegInfo();
// If we are adding the operand to the end of the list, our job is simpler.
// This is true most of the time, so this is a reasonable optimization.
if (isImpReg || NumImplicitOps == 0) {
// We can only do this optimization if we know that the operand list won't
// reallocate.
if (Operands.empty() || Operands.size()+1 <= Operands.capacity()) {
Operands.push_back(Op);
// Set the parent of the operand.
Operands.back().ParentMI = this;
// If the operand is a register, update the operand's use list.
if (Op.isReg())
Operands.back().AddRegOperandToRegInfo(RegInfo);
return;
}
}
// Otherwise, we have to insert a real operand before any implicit ones.
unsigned OpNo = Operands.size()-NumImplicitOps;
// If this instruction isn't embedded into a function, then we don't need to
// update any operand lists.
if (RegInfo == 0) {
// Simple insertion, no reginfo update needed for other register operands.
Operands.insert(Operands.begin()+OpNo, Op);
Operands[OpNo].ParentMI = this;
// Do explicitly set the reginfo for this operand though, to ensure the
// next/prev fields are properly nulled out.
if (Operands[OpNo].isReg())
Operands[OpNo].AddRegOperandToRegInfo(0);
} else if (Operands.size()+1 <= Operands.capacity()) {
// Otherwise, we have to remove register operands from their register use
// list, add the operand, then add the register operands back to their use
// list. This also must handle the case when the operand list reallocates
// to somewhere else.
// If insertion of this operand won't cause reallocation of the operand
// list, just remove the implicit operands, add the operand, then re-add all
// the rest of the operands.
for (unsigned i = OpNo, e = Operands.size(); i != e; ++i) {
assert(Operands[i].isReg() && "Should only be an implicit reg!");
Operands[i].RemoveRegOperandFromRegInfo();
}
// Add the operand. If it is a register, add it to the reg list.
Operands.insert(Operands.begin()+OpNo, Op);
Operands[OpNo].ParentMI = this;
if (Operands[OpNo].isReg())
Operands[OpNo].AddRegOperandToRegInfo(RegInfo);
// Re-add all the implicit ops.
for (unsigned i = OpNo+1, e = Operands.size(); i != e; ++i) {
assert(Operands[i].isReg() && "Should only be an implicit reg!");
Operands[i].AddRegOperandToRegInfo(RegInfo);
}
} else {
// Otherwise, we will be reallocating the operand list. Remove all reg
// operands from their list, then readd them after the operand list is
// reallocated.
RemoveRegOperandsFromUseLists();
Operands.insert(Operands.begin()+OpNo, Op);
Operands[OpNo].ParentMI = this;
// Re-add all the operands.
AddRegOperandsToUseLists(*RegInfo);
}
}
/// RemoveOperand - Erase an operand from an instruction, leaving it with one
/// fewer operand than it started with.
///
void MachineInstr::RemoveOperand(unsigned OpNo) {
assert(OpNo < Operands.size() && "Invalid operand number");
// Special case removing the last one.
if (OpNo == Operands.size()-1) {
// If needed, remove from the reg def/use list.
if (Operands.back().isReg() && Operands.back().isOnRegUseList())
Operands.back().RemoveRegOperandFromRegInfo();
Operands.pop_back();
return;
}
// Otherwise, we are removing an interior operand. If we have reginfo to
// update, remove all operands that will be shifted down from their reg lists,
// move everything down, then re-add them.
MachineRegisterInfo *RegInfo = getRegInfo();
if (RegInfo) {
for (unsigned i = OpNo, e = Operands.size(); i != e; ++i) {
if (Operands[i].isReg())
Operands[i].RemoveRegOperandFromRegInfo();
}
}
Operands.erase(Operands.begin()+OpNo);
if (RegInfo) {
for (unsigned i = OpNo, e = Operands.size(); i != e; ++i) {
if (Operands[i].isReg())
Operands[i].AddRegOperandToRegInfo(RegInfo);
}
}
}
/// addMemOperand - Add a MachineMemOperand to the machine instruction.
/// This function should be used only occasionally. The setMemRefs function
/// is the primary method for setting up a MachineInstr's MemRefs list.
void MachineInstr::addMemOperand(MachineFunction &MF,
MachineMemOperand *MO) {
mmo_iterator OldMemRefs = MemRefs;
mmo_iterator OldMemRefsEnd = MemRefsEnd;
size_t NewNum = (MemRefsEnd - MemRefs) + 1;
mmo_iterator NewMemRefs = MF.allocateMemRefsArray(NewNum);
mmo_iterator NewMemRefsEnd = NewMemRefs + NewNum;
std::copy(OldMemRefs, OldMemRefsEnd, NewMemRefs);
NewMemRefs[NewNum - 1] = MO;
MemRefs = NewMemRefs;
MemRefsEnd = NewMemRefsEnd;
}
/// removeFromParent - This method unlinks 'this' from the containing basic
/// block, and returns it, but does not delete it.
MachineInstr *MachineInstr::removeFromParent() {
assert(getParent() && "Not embedded in a basic block!");
getParent()->remove(this);
return this;
}
/// eraseFromParent - This method unlinks 'this' from the containing basic
/// block, and deletes it.
void MachineInstr::eraseFromParent() {
assert(getParent() && "Not embedded in a basic block!");
getParent()->erase(this);
}
/// OperandComplete - Return true if it's illegal to add a new operand
///
bool MachineInstr::OperandsComplete() const {
unsigned short NumOperands = TID->getNumOperands();
if (!TID->isVariadic() && getNumOperands()-NumImplicitOps >= NumOperands)
return true; // Broken: we have all the operands of this instruction!
return false;
}
/// getNumExplicitOperands - Returns the number of non-implicit operands.
///
unsigned MachineInstr::getNumExplicitOperands() const {
unsigned NumOperands = TID->getNumOperands();
if (!TID->isVariadic())
return NumOperands;
for (unsigned i = NumOperands, e = getNumOperands(); i != e; ++i) {
const MachineOperand &MO = getOperand(i);
if (!MO.isReg() || !MO.isImplicit())
NumOperands++;
}
return NumOperands;
}
/// isLabel - Returns true if the MachineInstr represents a label.
///
bool MachineInstr::isLabel() const {
return getOpcode() == TargetInstrInfo::DBG_LABEL ||
getOpcode() == TargetInstrInfo::EH_LABEL ||
getOpcode() == TargetInstrInfo::GC_LABEL;
}
/// isDebugLabel - Returns true if the MachineInstr represents a debug label.
///
bool MachineInstr::isDebugLabel() const {
return getOpcode() == TargetInstrInfo::DBG_LABEL;
}
/// findRegisterUseOperandIdx() - Returns the MachineOperand that is a use of
/// the specific register or -1 if it is not found. It further tightens
/// the search criteria to a use that kills the register if isKill is true.
int MachineInstr::findRegisterUseOperandIdx(unsigned Reg, bool isKill,
const TargetRegisterInfo *TRI) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
const MachineOperand &MO = getOperand(i);
if (!MO.isReg() || !MO.isUse())
continue;
unsigned MOReg = MO.getReg();
if (!MOReg)
continue;
if (MOReg == Reg ||
(TRI &&
TargetRegisterInfo::isPhysicalRegister(MOReg) &&
TargetRegisterInfo::isPhysicalRegister(Reg) &&
TRI->isSubRegister(MOReg, Reg)))
if (!isKill || MO.isKill())
return i;
}
return -1;
}
/// findRegisterDefOperandIdx() - Returns the operand index that is a def of
/// the specified register or -1 if it is not found. If isDead is true, defs
/// that are not dead are skipped. If TargetRegisterInfo is non-null, then it
/// also checks if there is a def of a super-register.
int MachineInstr::findRegisterDefOperandIdx(unsigned Reg, bool isDead,
const TargetRegisterInfo *TRI) const {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
const MachineOperand &MO = getOperand(i);
if (!MO.isReg() || !MO.isDef())
continue;
unsigned MOReg = MO.getReg();
if (MOReg == Reg ||
(TRI &&
TargetRegisterInfo::isPhysicalRegister(MOReg) &&
TargetRegisterInfo::isPhysicalRegister(Reg) &&
TRI->isSubRegister(MOReg, Reg)))
if (!isDead || MO.isDead())
return i;
}
return -1;
}
/// findFirstPredOperandIdx() - Find the index of the first operand in the
/// operand list that is used to represent the predicate. It returns -1 if
/// none is found.
int MachineInstr::findFirstPredOperandIdx() const {
const TargetInstrDesc &TID = getDesc();
if (TID.isPredicable()) {
for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
if (TID.OpInfo[i].isPredicate())
return i;
}
return -1;
}
/// isRegTiedToUseOperand - Given the index of a register def operand,
/// check if the register def is tied to a source operand, due to either
/// two-address elimination or inline assembly constraints. Returns the
/// first tied use operand index by reference is UseOpIdx is not null.
bool MachineInstr::
isRegTiedToUseOperand(unsigned DefOpIdx, unsigned *UseOpIdx) const {
if (getOpcode() == TargetInstrInfo::INLINEASM) {
assert(DefOpIdx >= 2);
const MachineOperand &MO = getOperand(DefOpIdx);
if (!MO.isReg() || !MO.isDef() || MO.getReg() == 0)
return false;
// Determine the actual operand index that corresponds to this index.
unsigned DefNo = 0;
unsigned DefPart = 0;
for (unsigned i = 1, e = getNumOperands(); i < e; ) {
const MachineOperand &FMO = getOperand(i);
// After the normal asm operands there may be additional imp-def regs.
if (!FMO.isImm())
return false;
// Skip over this def.
unsigned NumOps = InlineAsm::getNumOperandRegisters(FMO.getImm());
unsigned PrevDef = i + 1;
i = PrevDef + NumOps;
if (i > DefOpIdx) {
DefPart = DefOpIdx - PrevDef;
break;
}
++DefNo;
}
for (unsigned i = 1, e = getNumOperands(); i != e; ++i) {
const MachineOperand &FMO = getOperand(i);
if (!FMO.isImm())
continue;
if (i+1 >= e || !getOperand(i+1).isReg() || !getOperand(i+1).isUse())
continue;
unsigned Idx;
if (InlineAsm::isUseOperandTiedToDef(FMO.getImm(), Idx) &&
Idx == DefNo) {
if (UseOpIdx)
*UseOpIdx = (unsigned)i + 1 + DefPart;
return true;
}
}
return false;
}
assert(getOperand(DefOpIdx).isDef() && "DefOpIdx is not a def!");
const TargetInstrDesc &TID = getDesc();
for (unsigned i = 0, e = TID.getNumOperands(); i != e; ++i) {
const MachineOperand &MO = getOperand(i);
if (MO.isReg() && MO.isUse() &&
TID.getOperandConstraint(i, TOI::TIED_TO) == (int)DefOpIdx) {
if (UseOpIdx)
*UseOpIdx = (unsigned)i;
return true;
}
}
return false;
}
/// isRegTiedToDefOperand - Return true if the operand of the specified index
/// is a register use and it is tied to an def operand. It also returns the def
/// operand index by reference.
bool MachineInstr::
isRegTiedToDefOperand(unsigned UseOpIdx, unsigned *DefOpIdx) const {
if (getOpcode() == TargetInstrInfo::INLINEASM) {
const MachineOperand &MO = getOperand(UseOpIdx);
if (!MO.isReg() || !MO.isUse() || MO.getReg() == 0)
return false;
// Find the flag operand corresponding to UseOpIdx
unsigned FlagIdx, NumOps=0;
for (FlagIdx = 1; FlagIdx < UseOpIdx; FlagIdx += NumOps+1) {
const MachineOperand &UFMO = getOperand(FlagIdx);
// After the normal asm operands there may be additional imp-def regs.
if (!UFMO.isImm())
return false;
NumOps = InlineAsm::getNumOperandRegisters(UFMO.getImm());
assert(NumOps < getNumOperands() && "Invalid inline asm flag");
if (UseOpIdx < FlagIdx+NumOps+1)
break;
}
if (FlagIdx >= UseOpIdx)
return false;
const MachineOperand &UFMO = getOperand(FlagIdx);
unsigned DefNo;
if (InlineAsm::isUseOperandTiedToDef(UFMO.getImm(), DefNo)) {
if (!DefOpIdx)
return true;
unsigned DefIdx = 1;
// Remember to adjust the index. First operand is asm string, then there
// is a flag for each.
while (DefNo) {
const MachineOperand &FMO = getOperand(DefIdx);
assert(FMO.isImm());
// Skip over this def.
DefIdx += InlineAsm::getNumOperandRegisters(FMO.getImm()) + 1;
--DefNo;
}
*DefOpIdx = DefIdx + UseOpIdx - FlagIdx;
return true;
}
return false;
}
const TargetInstrDesc &TID = getDesc();
if (UseOpIdx >= TID.getNumOperands())
return false;
const MachineOperand &MO = getOperand(UseOpIdx);
if (!MO.isReg() || !MO.isUse())
return false;
int DefIdx = TID.getOperandConstraint(UseOpIdx, TOI::TIED_TO);
if (DefIdx == -1)
return false;
if (DefOpIdx)
*DefOpIdx = (unsigned)DefIdx;
return true;
}
/// copyKillDeadInfo - Copies kill / dead operand properties from MI.
///
void MachineInstr::copyKillDeadInfo(const MachineInstr *MI) {
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || (!MO.isKill() && !MO.isDead()))
continue;
for (unsigned j = 0, ee = getNumOperands(); j != ee; ++j) {
MachineOperand &MOp = getOperand(j);
if (!MOp.isIdenticalTo(MO))
continue;
if (MO.isKill())
MOp.setIsKill();
else
MOp.setIsDead();
break;
}
}
}
/// copyPredicates - Copies predicate operand(s) from MI.
void MachineInstr::copyPredicates(const MachineInstr *MI) {
const TargetInstrDesc &TID = MI->getDesc();
if (!TID.isPredicable())
return;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
if (TID.OpInfo[i].isPredicate()) {
// Predicated operands must be last operands.
addOperand(MI->getOperand(i));
}
}
}
/// isSafeToMove - Return true if it is safe to move this instruction. If
/// SawStore is set to true, it means that there is a store (or call) between
/// the instruction's location and its intended destination.
bool MachineInstr::isSafeToMove(const TargetInstrInfo *TII,
bool &SawStore,
AliasAnalysis *AA) const {
// Ignore stuff that we obviously can't move.
if (TID->mayStore() || TID->isCall()) {
SawStore = true;
return false;
}
if (TID->isTerminator() || TID->hasUnmodeledSideEffects())
return false;
// See if this instruction does a load. If so, we have to guarantee that the
// loaded value doesn't change between the load and the its intended
// destination. The check for isInvariantLoad gives the targe the chance to
// classify the load as always returning a constant, e.g. a constant pool
// load.
if (TID->mayLoad() && !isInvariantLoad(AA))
// Otherwise, this is a real load. If there is a store between the load and
// end of block, or if the load is volatile, we can't move it.
return !SawStore && !hasVolatileMemoryRef();
return true;
}
/// isSafeToReMat - Return true if it's safe to rematerialize the specified
/// instruction which defined the specified register instead of copying it.
bool MachineInstr::isSafeToReMat(const TargetInstrInfo *TII,
unsigned DstReg,
AliasAnalysis *AA) const {
bool SawStore = false;
if (!TII->isTriviallyReMaterializable(this, AA) ||
!isSafeToMove(TII, SawStore, AA))
return false;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
const MachineOperand &MO = getOperand(i);
if (!MO.isReg())
continue;
// FIXME: For now, do not remat any instruction with register operands.
// Later on, we can loosen the restriction is the register operands have
// not been modified between the def and use. Note, this is different from
// MachineSink because the code is no longer in two-address form (at least
// partially).
if (MO.isUse())
return false;
else if (!MO.isDead() && MO.getReg() != DstReg)
return false;
}
return true;
}
/// hasVolatileMemoryRef - Return true if this instruction may have a
/// volatile memory reference, or if the information describing the
/// memory reference is not available. Return false if it is known to
/// have no volatile memory references.
bool MachineInstr::hasVolatileMemoryRef() const {
// An instruction known never to access memory won't have a volatile access.
if (!TID->mayStore() &&
!TID->mayLoad() &&
!TID->isCall() &&
!TID->hasUnmodeledSideEffects())
return false;
// Otherwise, if the instruction has no memory reference information,
// conservatively assume it wasn't preserved.
if (memoperands_empty())
return true;
// Check the memory reference information for volatile references.
for (mmo_iterator I = memoperands_begin(), E = memoperands_end(); I != E; ++I)
if ((*I)->isVolatile())
return true;
return false;
}
/// isInvariantLoad - Return true if this instruction is loading from a
/// location whose value is invariant across the function. For example,
/// loading a value from the constant pool or from from the argument area
/// of a function if it does not change. This should only return true of
/// *all* loads the instruction does are invariant (if it does multiple loads).
bool MachineInstr::isInvariantLoad(AliasAnalysis *AA) const {
// If the instruction doesn't load at all, it isn't an invariant load.
if (!TID->mayLoad())
return false;
// If the instruction has lost its memoperands, conservatively assume that
// it may not be an invariant load.
if (memoperands_empty())
return false;
const MachineFrameInfo *MFI = getParent()->getParent()->getFrameInfo();
for (mmo_iterator I = memoperands_begin(),
E = memoperands_end(); I != E; ++I) {
if ((*I)->isVolatile()) return false;
if ((*I)->isStore()) return false;
if (const Value *V = (*I)->getValue()) {
// A load from a constant PseudoSourceValue is invariant.
if (const PseudoSourceValue *PSV = dyn_cast<PseudoSourceValue>(V))
if (PSV->isConstant(MFI))
continue;
// If we have an AliasAnalysis, ask it whether the memory is constant.
if (AA && AA->pointsToConstantMemory(V))
continue;
}
// Otherwise assume conservatively.
return false;
}
// Everything checks out.
return true;
}
void MachineInstr::dump() const {
errs() << " " << *this;
}
void MachineInstr::print(raw_ostream &OS, const TargetMachine *TM) const {
// Specialize printing if op#0 is definition
unsigned StartOp = 0;
if (getNumOperands() && getOperand(0).isReg() && getOperand(0).isDef()) {
getOperand(0).print(OS, TM);
OS << " = ";
++StartOp; // Don't print this operand again!
}
OS << getDesc().getName();
for (unsigned i = StartOp, e = getNumOperands(); i != e; ++i) {
if (i != StartOp)
OS << ",";
OS << " ";
getOperand(i).print(OS, TM);
}
if (!memoperands_empty()) {
OS << ", Mem:";
for (mmo_iterator i = memoperands_begin(), e = memoperands_end();
i != e; ++i) {
OS << **i;
if (next(i) != e)
OS << " ";
}
}
if (!debugLoc.isUnknown()) {
const MachineFunction *MF = getParent()->getParent();
DebugLocTuple DLT = MF->getDebugLocTuple(debugLoc);
DICompileUnit CU(DLT.CompileUnit);
OS << " [dbg: "
<< CU.getDirectory() << '/' << CU.getFilename() << ","
<< DLT.Line << ","
<< DLT.Col << "]";
}
OS << "\n";
}
bool MachineInstr::addRegisterKilled(unsigned IncomingReg,
const TargetRegisterInfo *RegInfo,
bool AddIfNotFound) {
bool isPhysReg = TargetRegisterInfo::isPhysicalRegister(IncomingReg);
bool hasAliases = isPhysReg && RegInfo->getAliasSet(IncomingReg);
bool Found = false;
SmallVector<unsigned,4> DeadOps;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
MachineOperand &MO = getOperand(i);
if (!MO.isReg() || !MO.isUse() || MO.isUndef())
continue;
unsigned Reg = MO.getReg();
if (!Reg)
continue;
if (Reg == IncomingReg) {
if (!Found) {
if (MO.isKill())
// The register is already marked kill.
return true;
if (isPhysReg && isRegTiedToDefOperand(i))
// Two-address uses of physregs must not be marked kill.
return true;
MO.setIsKill();
Found = true;
}
} else if (hasAliases && MO.isKill() &&
TargetRegisterInfo::isPhysicalRegister(Reg)) {
// A super-register kill already exists.
if (RegInfo->isSuperRegister(IncomingReg, Reg))
return true;
if (RegInfo->isSubRegister(IncomingReg, Reg))
DeadOps.push_back(i);
}
}
// Trim unneeded kill operands.
while (!DeadOps.empty()) {
unsigned OpIdx = DeadOps.back();
if (getOperand(OpIdx).isImplicit())
RemoveOperand(OpIdx);
else
getOperand(OpIdx).setIsKill(false);
DeadOps.pop_back();
}
// If not found, this means an alias of one of the operands is killed. Add a
// new implicit operand if required.
if (!Found && AddIfNotFound) {
addOperand(MachineOperand::CreateReg(IncomingReg,
false /*IsDef*/,
true /*IsImp*/,
true /*IsKill*/));
return true;
}
return Found;
}
bool MachineInstr::addRegisterDead(unsigned IncomingReg,
const TargetRegisterInfo *RegInfo,
bool AddIfNotFound) {
bool isPhysReg = TargetRegisterInfo::isPhysicalRegister(IncomingReg);
bool hasAliases = isPhysReg && RegInfo->getAliasSet(IncomingReg);
bool Found = false;
SmallVector<unsigned,4> DeadOps;
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
MachineOperand &MO = getOperand(i);
if (!MO.isReg() || !MO.isDef())
continue;
unsigned Reg = MO.getReg();
if (!Reg)
continue;
if (Reg == IncomingReg) {
if (!Found) {
if (MO.isDead())
// The register is already marked dead.
return true;
MO.setIsDead();
Found = true;
}
} else if (hasAliases && MO.isDead() &&
TargetRegisterInfo::isPhysicalRegister(Reg)) {
// There exists a super-register that's marked dead.
if (RegInfo->isSuperRegister(IncomingReg, Reg))
return true;
if (RegInfo->getSubRegisters(IncomingReg) &&
RegInfo->getSuperRegisters(Reg) &&
RegInfo->isSubRegister(IncomingReg, Reg))
DeadOps.push_back(i);
}
}
// Trim unneeded dead operands.
while (!DeadOps.empty()) {
unsigned OpIdx = DeadOps.back();
if (getOperand(OpIdx).isImplicit())
RemoveOperand(OpIdx);
else
getOperand(OpIdx).setIsDead(false);
DeadOps.pop_back();
}
// If not found, this means an alias of one of the operands is dead. Add a
// new implicit operand if required.
if (Found || !AddIfNotFound)
return Found;
addOperand(MachineOperand::CreateReg(IncomingReg,
true /*IsDef*/,
true /*IsImp*/,
false /*IsKill*/,
true /*IsDead*/));
return true;
}
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