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Implement generation of cmp R, C to not use an extra register

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6627 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2003-06-05 19:30:30 +00:00
parent 35333e16ee
commit 333864d81b
3 changed files with 67 additions and 23 deletions
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43
lib/Target/X86/X86ISelSimple.cpp
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@@ -579,26 +579,47 @@ bool ISel::EmitComparisonGetSignedness(unsigned OpNum, Value *Op0, Value *Op1) {
// The arguments are already supposed to be of the same type.
const Type *CompTy = Op0->getType();
bool isSigned = CompTy->isSigned();
unsigned reg1 = getReg(Op0);
unsigned reg2 = getReg(Op1);
unsigned Class = getClassB(CompTy);
unsigned Op0r = getReg(Op0);
// Special case handling of: cmp R, i
if (Class == cByte || Class == cShort || Class == cInt)
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
uint64_t Op1v;
if (ConstantSInt *CSI = dyn_cast<ConstantSInt>(CI))
Op1v = CSI->getValue();
else
Op1v = cast<ConstantUInt>(CI)->getValue();
// Mask off any upper bits of the constant, if there are any...
Op1v &= (1ULL << (8 << Class)) - 1;
switch (Class) {
case cByte: BuildMI(BB, X86::CMPri8, 2).addReg(Op0r).addZImm(Op1v);break;
case cShort: BuildMI(BB, X86::CMPri16,2).addReg(Op0r).addZImm(Op1v);break;
case cInt: BuildMI(BB, X86::CMPri32,2).addReg(Op0r).addZImm(Op1v);break;
default:
assert(0 && "Invalid class!");
}
return isSigned;
}
unsigned Op1r = getReg(Op1);
switch (Class) {
default: assert(0 && "Unknown type class!");
// Emit: cmp <var1>, <var2> (do the comparison). We can
// compare 8-bit with 8-bit, 16-bit with 16-bit, 32-bit with
// 32-bit.
case cByte:
BuildMI(BB, X86::CMPrr8, 2).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::CMPrr8, 2).addReg(Op0r).addReg(Op1r);
break;
case cShort:
BuildMI(BB, X86::CMPrr16, 2).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::CMPrr16, 2).addReg(Op0r).addReg(Op1r);
break;
case cInt:
BuildMI(BB, X86::CMPrr32, 2).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::CMPrr32, 2).addReg(Op0r).addReg(Op1r);
break;
case cFP:
BuildMI(BB, X86::FpUCOM, 2).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::FpUCOM, 2).addReg(Op0r).addReg(Op1r);
BuildMI(BB, X86::FNSTSWr8, 0);
BuildMI(BB, X86::SAHF, 1);
isSigned = false; // Compare with unsigned operators
@@ -609,8 +630,8 @@ bool ISel::EmitComparisonGetSignedness(unsigned OpNum, Value *Op0, Value *Op1) {
unsigned LoTmp = makeAnotherReg(Type::IntTy);
unsigned HiTmp = makeAnotherReg(Type::IntTy);
unsigned FinalTmp = makeAnotherReg(Type::IntTy);
BuildMI(BB, X86::XORrr32, 2, LoTmp).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::XORrr32, 2, HiTmp).addReg(reg1+1).addReg(reg2+1);
BuildMI(BB, X86::XORrr32, 2, LoTmp).addReg(Op0r).addReg(Op1r);
BuildMI(BB, X86::XORrr32, 2, HiTmp).addReg(Op0r+1).addReg(Op1r+1);
BuildMI(BB, X86::ORrr32, 2, FinalTmp).addReg(LoTmp).addReg(HiTmp);
break; // Allow the sete or setne to be generated from flags set by OR
} else {
@@ -627,9 +648,9 @@ bool ISel::EmitComparisonGetSignedness(unsigned OpNum, Value *Op0, Value *Op1) {
// classes! Until then, hardcode registers so that we can deal with their
// aliases (because we don't have conditional byte moves).
//
BuildMI(BB, X86::CMPrr32, 2).addReg(reg1).addReg(reg2);
BuildMI(BB, X86::CMPrr32, 2).addReg(Op0r).addReg(Op1r);
BuildMI(BB, SetCCOpcodeTab[0][OpNum], 0, X86::AL);
BuildMI(BB, X86::CMPrr32, 2).addReg(reg1+1).addReg(reg2+1);
BuildMI(BB, X86::CMPrr32, 2).addReg(Op0r+1).addReg(Op1r+1);
BuildMI(BB, SetCCOpcodeTab[isSigned][OpNum], 0, X86::BL);
BuildMI(BB, X86::CMOVErr16, 2, X86::BX).addReg(X86::BX).addReg(X86::AX);
// NOTE: visitSetCondInst knows that the value is dumped into the BL