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Codegen llvm.memset into rep stos[bwd]. Simplify code for llvm.memcpy

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llvm-svn: 11442
This commit is contained in:
Chris Lattner 2004-02-14 04:46:05 +00:00
parent 6890963e48
commit 69b716e81c
1 changed files with 67 additions and 13 deletions
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80
lib/Target/X86/InstSelectSimple.cpp
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@ -1158,6 +1158,7 @@ void ISel::LowerUnknownIntrinsicFunctionCalls(Function &F) {
case Intrinsic::va_copy:
case Intrinsic::va_end:
case Intrinsic::memcpy:
case Intrinsic::memset:
// We directly implement these intrinsics
break;
default:
@ -1200,7 +1201,7 @@ void ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
// Turn the byte code into # iterations
unsigned ByteReg;
unsigned CountReg;
unsigned Opcode;
switch (Align & 3) {
case 2: // WORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
@ -1209,6 +1210,7 @@ void ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
CountReg = makeAnotherReg(Type::IntTy);
BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(1);
}
Opcode = X86::REP_MOVSW;
break;
case 0: // DWORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
@ -1217,10 +1219,12 @@ void ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
CountReg = makeAnotherReg(Type::IntTy);
BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(2);
}
Opcode = X86::REP_MOVSD;
break;
case 1: // BYTE aligned
case 3: // BYTE aligned
CountReg = getReg(CI.getOperand(3));
Opcode = X86::REP_MOVSB;
break;
}
@ -1231,20 +1235,70 @@ void ISel::visitIntrinsicCall(Intrinsic::ID ID, CallInst &CI) {
BuildMI(BB, X86::MOVrr32, 1, X86::ECX).addReg(CountReg);
BuildMI(BB, X86::MOVrr32, 1, X86::EDI).addReg(TmpReg1);
BuildMI(BB, X86::MOVrr32, 1, X86::ESI).addReg(TmpReg2);
switch (Align & 3) {
case 1: // BYTE aligned
case 3: // BYTE aligned
BuildMI(BB, X86::REP_MOVSB, 0);
break;
case 2: // WORD aligned
BuildMI(BB, X86::REP_MOVSW, 0);
break;
case 0: // DWORD aligned
BuildMI(BB, X86::REP_MOVSD, 0);
break;
BuildMI(BB, Opcode, 0);
return;
}
case Intrinsic::memset: {
assert(CI.getNumOperands() == 5 && "Illegal llvm.memset call!");
unsigned Align = 1;
if (ConstantInt *AlignC = dyn_cast<ConstantInt>(CI.getOperand(4))) {
Align = AlignC->getRawValue();
if (Align == 0) Align = 1;
}
// Turn the byte code into # iterations
unsigned ByteReg;
unsigned CountReg;
unsigned Opcode;
if (ConstantInt *ValC = dyn_cast<ConstantInt>(CI.getOperand(2))) {
unsigned Val = ValC->getRawValue() & 255;
// If the value is a constant, then we can potentially use larger copies.
switch (Align & 3) {
case 2: // WORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg = getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/2));
} else {
CountReg = makeAnotherReg(Type::IntTy);
BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(1);
}
BuildMI(BB, X86::MOVir16, 1, X86::AX).addZImm((Val << 8) | Val);
Opcode = X86::REP_STOSW;
break;
case 0: // DWORD aligned
if (ConstantInt *I = dyn_cast<ConstantInt>(CI.getOperand(3))) {
CountReg = getReg(ConstantUInt::get(Type::UIntTy, I->getRawValue()/4));
} else {
CountReg = makeAnotherReg(Type::IntTy);
BuildMI(BB, X86::SHRir32, 2, CountReg).addReg(ByteReg).addZImm(2);
}
Val = (Val << 8) | Val;
BuildMI(BB, X86::MOVir32, 1, X86::EAX).addZImm((Val << 16) | Val);
Opcode = X86::REP_STOSD;
break;
case 1: // BYTE aligned
case 3: // BYTE aligned
CountReg = getReg(CI.getOperand(3));
BuildMI(BB, X86::MOVir8, 1, X86::AL).addZImm(Val);
Opcode = X86::REP_STOSB;
break;
}
} else {
// If it's not a constant value we are storing, just fall back. We could
// try to be clever to form 16 bit and 32 bit values, but we don't yet.
unsigned ValReg = getReg(CI.getOperand(2));
BuildMI(BB, X86::MOVrr8, 1, X86::AL).addReg(ValReg);
CountReg = getReg(CI.getOperand(3));
Opcode = X86::REP_STOSB;
}
// No matter what the alignment is, we put the source in ESI, the
// destination in EDI, and the count in ECX.
TmpReg1 = getReg(CI.getOperand(1));
//TmpReg2 = getReg(CI.getOperand(2));
BuildMI(BB, X86::MOVrr32, 1, X86::ECX).addReg(CountReg);
BuildMI(BB, X86::MOVrr32, 1, X86::EDI).addReg(TmpReg1);
BuildMI(BB, Opcode, 0);
return;
}