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Codegen FP select instructions into X86 conditional moves. Annoyingly enough

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the X86 does not support a full set of fp cmove instructions, so we can't always
fold the condition into the select.  :(  Yuck.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12577 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-03-31 22:03:35 +00:00
parent c1bab32bc5
commit 352eb48f8e
2 changed files with 72 additions and 28 deletions
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50
lib/Target/X86/InstSelectSimple.cpp
View File

@ -990,10 +990,37 @@ void ISel::emitSelectOperation(MachineBasicBlock *MBB,
// cmovS
switch (SelectClass) {
default:
case cFP:
assert(0 && "We don't support floating point selects yet, they should "
"have been lowered!");
default: assert(0 && "Unknown value class!");
case cFP: {
// Annoyingly, we don't have a full set of floating point conditional
// moves. :(
static const unsigned OpcodeTab[2][8] = {
{ X86::FCMOVNE, X86::FCMOVE, X86::FCMOVAE, X86::FCMOVB,
X86::FCMOVBE, X86::FCMOVA, 0, 0 },
{ X86::FCMOVNE, X86::FCMOVE, 0, 0, 0, 0, 0, 0 },
};
Opcode = OpcodeTab[isSigned][OpNum];
// If opcode == 0, we hit a case that we don't support. Output a setcc
// and compare the result against zero.
if (Opcode == 0) {
unsigned CompClass = getClassB(CompTy);
unsigned CondReg;
if (CompClass != cLong || OpNum < 2) {
CondReg = makeAnotherReg(Type::BoolTy);
// Handle normal comparisons with a setcc instruction...
BuildMI(*MBB, IP, SetCCOpcodeTab[isSigned][OpNum], 0, CondReg);
} else {
// Long comparisons end up in the BL register.
CondReg = X86::BL;
}
// FIXME: Should generate a 'tst r, r'
BuildMI(*MBB, IP, X86::CMP8ri, 2).addReg(CondReg).addImm(0);
Opcode = X86::FCMOVE;
}
break;
}
case cByte:
case cShort: {
static const unsigned OpcodeTab[2][8] = {
@ -1020,20 +1047,15 @@ void ISel::emitSelectOperation(MachineBasicBlock *MBB,
} else {
// Get the value being branched on, and use it to set the condition codes.
unsigned CondReg = getReg(Cond, MBB, IP);
// FIXME: Should generate a 'tst r, r'
BuildMI(*MBB, IP, X86::CMP8ri, 2).addReg(CondReg).addImm(0);
switch (SelectClass) {
default:
case cFP:
assert(0 && "We don't support floating point selects yet, they should "
"have been lowered!");
default: assert(0 && "Unknown value class!");
case cFP: Opcode = X86::FCMOVE; break;
case cByte:
case cShort:
Opcode = X86::CMOVE16rr;
break;
case cShort: Opcode = X86::CMOVE16rr; break;
case cInt:
case cLong:
Opcode = X86::CMOVE32rr;
break;
case cLong: Opcode = X86::CMOVE32rr; break;
}
}

50
lib/Target/X86/X86ISelSimple.cpp
View File

@ -990,10 +990,37 @@ void ISel::emitSelectOperation(MachineBasicBlock *MBB,
// cmovS
switch (SelectClass) {
default:
case cFP:
assert(0 && "We don't support floating point selects yet, they should "
"have been lowered!");
default: assert(0 && "Unknown value class!");
case cFP: {
// Annoyingly, we don't have a full set of floating point conditional
// moves. :(
static const unsigned OpcodeTab[2][8] = {
{ X86::FCMOVNE, X86::FCMOVE, X86::FCMOVAE, X86::FCMOVB,
X86::FCMOVBE, X86::FCMOVA, 0, 0 },
{ X86::FCMOVNE, X86::FCMOVE, 0, 0, 0, 0, 0, 0 },
};
Opcode = OpcodeTab[isSigned][OpNum];
// If opcode == 0, we hit a case that we don't support. Output a setcc
// and compare the result against zero.
if (Opcode == 0) {
unsigned CompClass = getClassB(CompTy);
unsigned CondReg;
if (CompClass != cLong || OpNum < 2) {
CondReg = makeAnotherReg(Type::BoolTy);
// Handle normal comparisons with a setcc instruction...
BuildMI(*MBB, IP, SetCCOpcodeTab[isSigned][OpNum], 0, CondReg);
} else {
// Long comparisons end up in the BL register.
CondReg = X86::BL;
}
// FIXME: Should generate a 'tst r, r'
BuildMI(*MBB, IP, X86::CMP8ri, 2).addReg(CondReg).addImm(0);
Opcode = X86::FCMOVE;
}
break;
}
case cByte:
case cShort: {
static const unsigned OpcodeTab[2][8] = {
@ -1020,20 +1047,15 @@ void ISel::emitSelectOperation(MachineBasicBlock *MBB,
} else {
// Get the value being branched on, and use it to set the condition codes.
unsigned CondReg = getReg(Cond, MBB, IP);
// FIXME: Should generate a 'tst r, r'
BuildMI(*MBB, IP, X86::CMP8ri, 2).addReg(CondReg).addImm(0);
switch (SelectClass) {
default:
case cFP:
assert(0 && "We don't support floating point selects yet, they should "
"have been lowered!");
default: assert(0 && "Unknown value class!");
case cFP: Opcode = X86::FCMOVE; break;
case cByte:
case cShort:
Opcode = X86::CMOVE16rr;
break;
case cShort: Opcode = X86::CMOVE16rr; break;
case cInt:
case cLong:
Opcode = X86::CMOVE32rr;
break;
case cLong: Opcode = X86::CMOVE32rr; break;
}
}