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Cosmetic changes:

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- Comment fixes.
 - Moar whitespace.
 - Made ivars "private" by default.
No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50926 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling
2008-05-10 00:12:52 +00:00
parent 23573e5be6
commit 637980edce
1 changed files with 48 additions and 36 deletions
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78
lib/CodeGen/TwoAddressInstructionPass.cpp
View File

@@ -49,26 +49,31 @@ STATISTIC(NumConvertedTo3Addr, "Number of instructions promoted to 3-address");
STATISTIC(Num3AddrSunk, "Number of 3-address instructions sunk");
namespace {
struct VISIBILITY_HIDDEN TwoAddressInstructionPass
class VISIBILITY_HIDDEN TwoAddressInstructionPass
: public MachineFunctionPass {
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
MachineRegisterInfo *MRI;
LiveVariables *LV;
bool Sink3AddrInstruction(MachineBasicBlock *MBB, MachineInstr *MI,
unsigned Reg,
MachineBasicBlock::iterator OldPos);
public:
static char ID; // Pass identification, replacement for typeid
TwoAddressInstructionPass() : MachineFunctionPass((intptr_t)&ID) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LiveVariables>();
AU.addPreserved<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
AU.addPreservedID(PHIEliminationID);
MachineFunctionPass::getAnalysisUsage(AU);
}
/// runOnMachineFunction - pass entry point
/// runOnMachineFunction - Pass entry point.
bool runOnMachineFunction(MachineFunction&);
private:
bool Sink3AddrInstruction(MachineBasicBlock *MBB, MachineInstr *MI,
unsigned Reg,
MachineBasicBlock::iterator OldPos);
};
char TwoAddressInstructionPass::ID = 0;
@@ -78,19 +83,11 @@ namespace {
const PassInfo *llvm::TwoAddressInstructionPassID = X.getPassInfo();
void TwoAddressInstructionPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<LiveVariables>();
AU.addPreserved<LiveVariables>();
AU.addPreservedID(MachineLoopInfoID);
AU.addPreservedID(MachineDominatorsID);
AU.addPreservedID(PHIEliminationID);
MachineFunctionPass::getAnalysisUsage(AU);
}
/// Sink3AddrInstruction - A two-address instruction has been converted to a
/// three-address instruction to avoid clobbering a register. Try to sink it
/// past the instruction that would kill the above mentioned register to
/// reduce register pressure.
/// past the instruction that would kill the above mentioned register to reduce
/// register pressure.
///
bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
MachineInstr *MI, unsigned SavedReg,
MachineBasicBlock::iterator OldPos) {
@@ -101,6 +98,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
unsigned DefReg = 0;
SmallSet<unsigned, 4> UseRegs;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (!MO.isRegister())
@@ -123,6 +121,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
// Find the instruction that kills SavedReg.
MachineInstr *KillMI = NULL;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(SavedReg),
UE = MRI->use_end(); UI != UE; ++UI) {
MachineOperand &UseMO = UI.getOperand();
@@ -131,19 +130,23 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
KillMI = UseMO.getParent();
break;
}
if (!KillMI || KillMI->getParent() != MBB)
return false;
// If any of the definitions are used by another instruction between
// the position and the kill use, then it's not safe to sink it.
// FIXME: This can be sped up if there is an easy way to query whether
// an instruction if before or after another instruction. Then we can
// use MachineRegisterInfo def / use instead.
// If any of the definitions are used by another instruction between the
// position and the kill use, then it's not safe to sink it.
//
// FIXME: This can be sped up if there is an easy way to query whether an
// instruction if before or after another instruction. Then we can use
// MachineRegisterInfo def / use instead.
MachineOperand *KillMO = NULL;
MachineBasicBlock::iterator KillPos = KillMI;
++KillPos;
for (MachineBasicBlock::iterator I = next(OldPos); I != KillPos; ++I) {
MachineInstr *OtherMI = I;
for (unsigned i = 0, e = OtherMI->getNumOperands(); i != e; ++i) {
MachineOperand &MO = OtherMI->getOperand(i);
if (!MO.isRegister())
@@ -153,6 +156,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
continue;
if (DefReg == MOReg)
return false;
if (MO.isKill()) {
if (OtherMI == KillMI && MOReg == SavedReg)
// Save the operand that kills the register. We want unset the kill
@@ -181,8 +185,7 @@ bool TwoAddressInstructionPass::Sink3AddrInstruction(MachineBasicBlock *MBB,
return true;
}
/// runOnMachineFunction - Reduce two-address instructions to two
/// operands.
/// runOnMachineFunction - Reduce two-address instructions to two operands.
///
bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
DOUT << "Machine Function\n";
@@ -203,8 +206,8 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
mi != me; ) {
MachineBasicBlock::iterator nmi = next(mi);
const TargetInstrDesc &TID = mi->getDesc();
bool FirstTied = true;
for (unsigned si = 1, e = TID.getNumOperands(); si < e; ++si) {
int ti = TID.getOperandConstraint(si, TOI::TIED_TO);
if (ti == -1)
@@ -214,15 +217,16 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
++NumTwoAddressInstrs;
DOUT << '\t'; DEBUG(mi->print(*cerr.stream(), &TM));
}
FirstTied = false;
assert(mi->getOperand(si).isRegister() && mi->getOperand(si).getReg() &&
mi->getOperand(si).isUse() && "two address instruction invalid");
// if the two operands are the same we just remove the use
// If the two operands are the same we just remove the use
// and mark the def as def&use, otherwise we have to insert a copy.
if (mi->getOperand(ti).getReg() != mi->getOperand(si).getReg()) {
// rewrite:
// Rewrite:
// a = b op c
// to:
// a = b
@@ -257,9 +261,11 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
assert(mi->getOperand(3-si).isRegister() &&
"Not a proper commutative instruction!");
unsigned regC = mi->getOperand(3-si).getReg();
if (mi->killsRegister(regC)) {
DOUT << "2addr: COMMUTING : " << *mi;
MachineInstr *NewMI = TII->commuteInstruction(mi);
if (NewMI == 0) {
DOUT << "2addr: COMMUTING FAILED!\n";
} else {
@@ -293,19 +299,22 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
DOUT << "2addr: CONVERTING 2-ADDR: " << *mi;
DOUT << "2addr: TO 3-ADDR: " << *New;
bool Sunk = false;
if (New->findRegisterUseOperand(regB, false, TRI))
// FIXME: Temporary workaround. If the new instruction doesn't
// uses regB, convertToThreeAddress must have created more
// then one instruction.
Sunk = Sink3AddrInstruction(mbbi, New, regB, mi);
mbbi->erase(mi); // Nuke the old inst.
if (!Sunk) {
mi = New;
nmi = next(mi);
}
++NumConvertedTo3Addr;
// Done with this instruction.
break;
break; // Done with this instruction.
}
}
}
@@ -317,17 +326,19 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
MachineBasicBlock::iterator prevMi = prior(mi);
DOUT << "\t\tprepend:\t"; DEBUG(prevMi->print(*cerr.stream(), &TM));
// update live variables for regB
// Update live variables for regB.
LiveVariables::VarInfo& varInfoB = LV->getVarInfo(regB);
// regB is used in this BB.
varInfoB.UsedBlocks[mbbi->getNumber()] = true;
if (LV->removeVirtualRegisterKilled(regB, mbbi, mi))
LV->addVirtualRegisterKilled(regB, prevMi);
if (LV->removeVirtualRegisterDead(regB, mbbi, mi))
LV->addVirtualRegisterDead(regB, prevMi);
// replace all occurences of regB with regA
// Replace all occurences of regB with regA.
for (unsigned i = 0, e = mi->getNumOperands(); i != e; ++i) {
if (mi->getOperand(i).isRegister() &&
mi->getOperand(i).getReg() == regB)
@@ -341,6 +352,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
DOUT << "\t\trewrite to:\t"; DEBUG(mi->print(*cerr.stream(), &TM));
}
mi = nmi;
}
}