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* Add utility functions: convert SetCC => PPC opcode and invert PPC opcode

Browse Source 
* If SetCondInst is folded into BranchInst (and it is the only user), do not
  emit code for SetCondInst
* Fix assembly opcodes in comments in visitSetCondInst()
* Fix codegen of conditional branches


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14643 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Misha Brukman 2004-07-06 15:32:44 +00:00
parent 3571b72606
commit e9c6551fed
2 changed files with 98 additions and 68 deletions
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83
lib/Target/PowerPC/PPC32ISelSimple.cpp
View File

@ -722,7 +722,7 @@ static SetCondInst *canFoldSetCCIntoBranchOrSelect(Value *V) {
// order of the opcodes.
//
static unsigned getSetCCNumber(unsigned Opcode) {
switch(Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: return 0;
case Instruction::SetNE: return 1;
@ -733,6 +733,30 @@ static unsigned getSetCCNumber(unsigned Opcode) {
}
}
static unsigned getPPCOpcodeForSetCCNumber(unsigned Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: return PPC32::BEQ;
case Instruction::SetNE: return PPC32::BNE;
case Instruction::SetLT: return PPC32::BLT;
case Instruction::SetGE: return PPC32::BGE;
case Instruction::SetGT: return PPC32::BGT;
case Instruction::SetLE: return PPC32::BLE;
}
}
static unsigned invertPPCBranchOpcode(unsigned Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown PPC32 branch opcode!");
case PPC32::BEQ: return PPC32::BNE;
case PPC32::BNE: return PPC32::BEQ;
case PPC32::BLT: return PPC32::BGE;
case PPC32::BGE: return PPC32::BLT;
case PPC32::BGT: return PPC32::BLE;
case PPC32::BLE: return PPC32::BGT;
}
}
/// emitUCOM - emits an unordered FP compare.
void ISel::emitUCOM(MachineBasicBlock *MBB, MachineBasicBlock::iterator IP,
unsigned LHS, unsigned RHS) {
@ -751,7 +775,7 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
// Special case handling of: cmp R, i
if (isa<ConstantPointerNull>(Op1)) {
BuildMI(*MBB, IP, PPC32::CMPI, 2, PPC32::CR0).addReg(Op0r).addImm(0);
BuildMI(*MBB, IP, PPC32::CMPI, 2, PPC32::CR0).addReg(Op0r).addImm(0);
} else if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Class == cByte || Class == cShort || Class == cInt) {
unsigned Op1v = CI->getRawValue();
@ -839,6 +863,17 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
/// visitSetCondInst -
///
void ISel::visitSetCondInst(SetCondInst &I) {
// If the only user of this SetCC is a branch or a select, we don't have to
// code-gen this instruction, it will be done more compactly for us later.
// FIXME: perhaps there could be several branches/selects using this SetCC and
// this SetCC could still be a valid candidate for folding? Then the problem
// becomes with live range, whether or not the uses span function calls, other
// branches with can overwrite the condition register, etc.
User *user = I.hasOneUse() ? I.use_back() : 0;
if (canFoldSetCCIntoBranchOrSelect(&I) &&
(isa<BranchInst>(user) || isa<SelectInst>(user)))
return;
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned Op1Reg = getReg(I.getOperand(1));
unsigned DestReg = getReg(I);
@ -848,21 +883,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// Compare the two values.
BuildMI(BB, PPC32::CMPW, 2, PPC32::CR0).addReg(Op0Reg).addReg(Op1Reg);
unsigned BranchIdx;
switch (I.getOpcode()) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: BranchIdx = 0; break;
case Instruction::SetNE: BranchIdx = 1; break;
case Instruction::SetLT: BranchIdx = 2; break;
case Instruction::SetGT: BranchIdx = 3; break;
case Instruction::SetLE: BranchIdx = 4; break;
case Instruction::SetGE: BranchIdx = 5; break;
}
static unsigned OpcodeTab[] = {
PPC32::BEQ, PPC32::BNE, PPC32::BLT, PPC32::BGT, PPC32::BLE, PPC32::BGE
};
unsigned Opcode = OpcodeTab[BranchIdx];
unsigned Opcode = getPPCOpcodeForSetCCNumber(I.getOpcode());
MachineBasicBlock *thisMBB = BB;
const BasicBlock *LLVM_BB = BB->getBasicBlock();
// thisMBB:
@ -886,7 +907,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// copy0MBB:
// %FalseValue = li 0
// ba sinkMBB
// b sinkMBB
BB = copy0MBB;
unsigned FalseValue = makeAnotherReg(I.getType());
BuildMI(BB, PPC32::LI, 1, FalseValue).addZImm(0);
@ -903,7 +924,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// copy1MBB:
// %TrueValue = li 1
// ba sinkMBB
// b sinkMBB
BB = copy1MBB;
unsigned TrueValue = makeAnotherReg (I.getType ());
BuildMI(BB, PPC32::LI, 1, TrueValue).addZImm(1);
@ -1091,9 +1112,9 @@ void ISel::visitBranchInst(BranchInst &BI) {
BB->addSuccessor (MBBMap[BI.getSuccessor(1)]);
BasicBlock *NextBB = getBlockAfter(BI.getParent()); // BB after current one
if (!BI.isConditional()) { // Unconditional branch?
if (BI.getSuccessor(0) != NextBB)
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, PPC32::B, 1).addMBB(MBBMap[BI.getSuccessor(0)]);
return;
}
@ -1104,14 +1125,14 @@ void ISel::visitBranchInst(BranchInst &BI) {
// Nope, cannot fold setcc into this branch. Emit a branch on a condition
// computed some other way...
unsigned condReg = getReg(BI.getCondition());
BuildMI(BB, PPC32::CMPLI, 3, PPC32::CR0).addImm(0).addReg(condReg)
BuildMI(BB, PPC32::CMPLI, 3, PPC32::CR1).addImm(0).addReg(condReg)
.addImm(0);
if (BI.getSuccessor(1) == NextBB) {
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, PPC32::BC, 3).addImm(4).addImm(2)
BuildMI(BB, PPC32::BNE, 2).addReg(PPC32::CR1)
.addMBB(MBBMap[BI.getSuccessor(0)]);
} else {
BuildMI(BB, PPC32::BC, 3).addImm(12).addImm(2)
BuildMI(BB, PPC32::BNE, 2).addReg(PPC32::CR1)
.addMBB(MBBMap[BI.getSuccessor(1)]);
if (BI.getSuccessor(0) != NextBB)
@ -1121,26 +1142,20 @@ void ISel::visitBranchInst(BranchInst &BI) {
}
unsigned OpNum = getSetCCNumber(SCI->getOpcode());
unsigned Opcode = getPPCOpcodeForSetCCNumber(SCI->getOpcode());
MachineBasicBlock::iterator MII = BB->end();
OpNum = EmitComparison(OpNum, SCI->getOperand(0), SCI->getOperand(1), BB,MII);
const Type *CompTy = SCI->getOperand(0)->getType();
bool isSigned = CompTy->isSigned() && getClassB(CompTy) != cFP;
static const unsigned BITab[6] = { 2, 2, 0, 0, 1, 1 };
unsigned BO_true = (OpNum % 2 == 0) ? 12 : 4;
unsigned BO_false = (OpNum % 2 == 0) ? 4 : 12;
unsigned BIval = BITab[0];
if (BI.getSuccessor(0) != NextBB) {
BuildMI(BB, PPC32::BC, 3).addImm(BO_true).addImm(BIval)
BuildMI(BB, Opcode, 2).addReg(PPC32::CR0)
.addMBB(MBBMap[BI.getSuccessor(0)]);
if (BI.getSuccessor(1) != NextBB)
BuildMI(BB, PPC32::B, 1).addMBB(MBBMap[BI.getSuccessor(1)]);
} else {
// Change to the inverse condition...
if (BI.getSuccessor(1) != NextBB) {
BuildMI(BB, PPC32::BC, 3).addImm(BO_false).addImm(BIval)
Opcode = invertPPCBranchOpcode(Opcode);
BuildMI(BB, Opcode, 2).addReg(PPC32::CR0)
.addMBB(MBBMap[BI.getSuccessor(1)]);
}
}

83
lib/Target/PowerPC/PowerPCISelSimple.cpp
View File

@ -722,7 +722,7 @@ static SetCondInst *canFoldSetCCIntoBranchOrSelect(Value *V) {
// order of the opcodes.
//
static unsigned getSetCCNumber(unsigned Opcode) {
switch(Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: return 0;
case Instruction::SetNE: return 1;
@ -733,6 +733,30 @@ static unsigned getSetCCNumber(unsigned Opcode) {
}
}
static unsigned getPPCOpcodeForSetCCNumber(unsigned Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: return PPC32::BEQ;
case Instruction::SetNE: return PPC32::BNE;
case Instruction::SetLT: return PPC32::BLT;
case Instruction::SetGE: return PPC32::BGE;
case Instruction::SetGT: return PPC32::BGT;
case Instruction::SetLE: return PPC32::BLE;
}
}
static unsigned invertPPCBranchOpcode(unsigned Opcode) {
switch (Opcode) {
default: assert(0 && "Unknown PPC32 branch opcode!");
case PPC32::BEQ: return PPC32::BNE;
case PPC32::BNE: return PPC32::BEQ;
case PPC32::BLT: return PPC32::BGE;
case PPC32::BGE: return PPC32::BLT;
case PPC32::BGT: return PPC32::BLE;
case PPC32::BLE: return PPC32::BGT;
}
}
/// emitUCOM - emits an unordered FP compare.
void ISel::emitUCOM(MachineBasicBlock *MBB, MachineBasicBlock::iterator IP,
unsigned LHS, unsigned RHS) {
@ -751,7 +775,7 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
// Special case handling of: cmp R, i
if (isa<ConstantPointerNull>(Op1)) {
BuildMI(*MBB, IP, PPC32::CMPI, 2, PPC32::CR0).addReg(Op0r).addImm(0);
BuildMI(*MBB, IP, PPC32::CMPI, 2, PPC32::CR0).addReg(Op0r).addImm(0);
} else if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
if (Class == cByte || Class == cShort || Class == cInt) {
unsigned Op1v = CI->getRawValue();
@ -839,6 +863,17 @@ unsigned ISel::EmitComparison(unsigned OpNum, Value *Op0, Value *Op1,
/// visitSetCondInst -
///
void ISel::visitSetCondInst(SetCondInst &I) {
// If the only user of this SetCC is a branch or a select, we don't have to
// code-gen this instruction, it will be done more compactly for us later.
// FIXME: perhaps there could be several branches/selects using this SetCC and
// this SetCC could still be a valid candidate for folding? Then the problem
// becomes with live range, whether or not the uses span function calls, other
// branches with can overwrite the condition register, etc.
User *user = I.hasOneUse() ? I.use_back() : 0;
if (canFoldSetCCIntoBranchOrSelect(&I) &&
(isa<BranchInst>(user) || isa<SelectInst>(user)))
return;
unsigned Op0Reg = getReg(I.getOperand(0));
unsigned Op1Reg = getReg(I.getOperand(1));
unsigned DestReg = getReg(I);
@ -848,21 +883,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// Compare the two values.
BuildMI(BB, PPC32::CMPW, 2, PPC32::CR0).addReg(Op0Reg).addReg(Op1Reg);
unsigned BranchIdx;
switch (I.getOpcode()) {
default: assert(0 && "Unknown setcc instruction!");
case Instruction::SetEQ: BranchIdx = 0; break;
case Instruction::SetNE: BranchIdx = 1; break;
case Instruction::SetLT: BranchIdx = 2; break;
case Instruction::SetGT: BranchIdx = 3; break;
case Instruction::SetLE: BranchIdx = 4; break;
case Instruction::SetGE: BranchIdx = 5; break;
}
static unsigned OpcodeTab[] = {
PPC32::BEQ, PPC32::BNE, PPC32::BLT, PPC32::BGT, PPC32::BLE, PPC32::BGE
};
unsigned Opcode = OpcodeTab[BranchIdx];
unsigned Opcode = getPPCOpcodeForSetCCNumber(I.getOpcode());
MachineBasicBlock *thisMBB = BB;
const BasicBlock *LLVM_BB = BB->getBasicBlock();
// thisMBB:
@ -886,7 +907,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// copy0MBB:
// %FalseValue = li 0
// ba sinkMBB
// b sinkMBB
BB = copy0MBB;
unsigned FalseValue = makeAnotherReg(I.getType());
BuildMI(BB, PPC32::LI, 1, FalseValue).addZImm(0);
@ -903,7 +924,7 @@ void ISel::visitSetCondInst(SetCondInst &I) {
// copy1MBB:
// %TrueValue = li 1
// ba sinkMBB
// b sinkMBB
BB = copy1MBB;
unsigned TrueValue = makeAnotherReg (I.getType ());
BuildMI(BB, PPC32::LI, 1, TrueValue).addZImm(1);
@ -1091,9 +1112,9 @@ void ISel::visitBranchInst(BranchInst &BI) {
BB->addSuccessor (MBBMap[BI.getSuccessor(1)]);
BasicBlock *NextBB = getBlockAfter(BI.getParent()); // BB after current one
if (!BI.isConditional()) { // Unconditional branch?
if (BI.getSuccessor(0) != NextBB)
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, PPC32::B, 1).addMBB(MBBMap[BI.getSuccessor(0)]);
return;
}
@ -1104,14 +1125,14 @@ void ISel::visitBranchInst(BranchInst &BI) {
// Nope, cannot fold setcc into this branch. Emit a branch on a condition
// computed some other way...
unsigned condReg = getReg(BI.getCondition());
BuildMI(BB, PPC32::CMPLI, 3, PPC32::CR0).addImm(0).addReg(condReg)
BuildMI(BB, PPC32::CMPLI, 3, PPC32::CR1).addImm(0).addReg(condReg)
.addImm(0);
if (BI.getSuccessor(1) == NextBB) {
if (BI.getSuccessor(0) != NextBB)
BuildMI(BB, PPC32::BC, 3).addImm(4).addImm(2)
BuildMI(BB, PPC32::BNE, 2).addReg(PPC32::CR1)
.addMBB(MBBMap[BI.getSuccessor(0)]);
} else {
BuildMI(BB, PPC32::BC, 3).addImm(12).addImm(2)
BuildMI(BB, PPC32::BNE, 2).addReg(PPC32::CR1)
.addMBB(MBBMap[BI.getSuccessor(1)]);
if (BI.getSuccessor(0) != NextBB)
@ -1121,26 +1142,20 @@ void ISel::visitBranchInst(BranchInst &BI) {
}
unsigned OpNum = getSetCCNumber(SCI->getOpcode());
unsigned Opcode = getPPCOpcodeForSetCCNumber(SCI->getOpcode());
MachineBasicBlock::iterator MII = BB->end();
OpNum = EmitComparison(OpNum, SCI->getOperand(0), SCI->getOperand(1), BB,MII);
const Type *CompTy = SCI->getOperand(0)->getType();
bool isSigned = CompTy->isSigned() && getClassB(CompTy) != cFP;
static const unsigned BITab[6] = { 2, 2, 0, 0, 1, 1 };
unsigned BO_true = (OpNum % 2 == 0) ? 12 : 4;
unsigned BO_false = (OpNum % 2 == 0) ? 4 : 12;
unsigned BIval = BITab[0];
if (BI.getSuccessor(0) != NextBB) {
BuildMI(BB, PPC32::BC, 3).addImm(BO_true).addImm(BIval)
BuildMI(BB, Opcode, 2).addReg(PPC32::CR0)
.addMBB(MBBMap[BI.getSuccessor(0)]);
if (BI.getSuccessor(1) != NextBB)
BuildMI(BB, PPC32::B, 1).addMBB(MBBMap[BI.getSuccessor(1)]);
} else {
// Change to the inverse condition...
if (BI.getSuccessor(1) != NextBB) {
BuildMI(BB, PPC32::BC, 3).addImm(BO_false).addImm(BIval)
Opcode = invertPPCBranchOpcode(Opcode);
BuildMI(BB, Opcode, 2).addReg(PPC32::CR0)
.addMBB(MBBMap[BI.getSuccessor(1)]);
}
}