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simplify the add/sub_parts code

llvm-svn: 23065
This commit is contained in:
Chris Lattner 2005-08-25 23:19:58 +00:00
parent 05ed995816
commit e4cf3ab5d4

View File

@ -1384,7 +1384,7 @@ unsigned ISel::SelectExpr(SDOperand N, bool Recording) {
case ISD::UDIV: case ISD::UDIV:
// If this is a divide by constant, we can emit code using some magic // If this is a divide by constant, we can emit code using some magic
// constants to implement it as a multiply instead. // constants to implement it as a multiply instead.
if (isIntImmediate(N.getOperand(1), Tmp3) && (signed)Tmp3 > 1) { if (isIntImmediate(N.getOperand(1), Tmp3) && Tmp3) {
ExprMap.erase(N); ExprMap.erase(N);
return SelectExpr(BuildUDIVSequence(N)); return SelectExpr(BuildUDIVSequence(N));
} }
@ -1404,33 +1404,41 @@ unsigned ISel::SelectExpr(SDOperand N, bool Recording) {
assert(N.getNumOperands() == 4 && N.getValueType() == MVT::i32 && assert(N.getNumOperands() == 4 && N.getValueType() == MVT::i32 &&
"Not an i64 add/sub!"); "Not an i64 add/sub!");
unsigned Tmp4 = 0; unsigned Tmp4 = 0;
bool ME = isIntImmediate(N.getOperand(3),Tmp3) && ((signed)Tmp3 == -1);
bool ZE = isIntImmediate(N.getOperand(3),Tmp3) && (Tmp3 == 0);
bool IM = isIntImmediate(N.getOperand(2),Tmp3) && ((signed)Tmp3 >= -32768 ||
(signed)Tmp3 < 32768);
Tmp1 = SelectExpr(N.getOperand(0)); Tmp1 = SelectExpr(N.getOperand(0));
Tmp2 = SelectExpr(N.getOperand(1)); Tmp2 = SelectExpr(N.getOperand(1));
if (!IM || N.getOpcode() == ISD::SUB_PARTS)
Tmp3 = SelectExpr(N.getOperand(2));
if ((!ME && !ZE) || N.getOpcode() == ISD::SUB_PARTS)
Tmp4 = SelectExpr(N.getOperand(3));
if (N.getOpcode() == ISD::ADD_PARTS) { if (N.getOpcode() == ISD::ADD_PARTS) {
// Codegen the low 32 bits of the add. Interestingly, there is no shifted bool ME, ZE;
// form of add immediate carrying. if (isIntImmediate(N.getOperand(3), Tmp3)) {
if (IM) ME = (signed)Tmp3 == -1;
ZE = Tmp3 == 0;
}
if (!ZE && !ME)
Tmp4 = SelectExpr(N.getOperand(3));
if (isIntImmediate(N.getOperand(2), Tmp3) &&
((signed)Tmp3 >= -32768 || (signed)Tmp3 < 32768)) {
// Codegen the low 32 bits of the add. Interestingly, there is no
// shifted form of add immediate carrying.
BuildMI(BB, PPC::ADDIC, 2, Result).addReg(Tmp1).addSImm(Tmp3); BuildMI(BB, PPC::ADDIC, 2, Result).addReg(Tmp1).addSImm(Tmp3);
else } else {
Tmp3 = SelectExpr(N.getOperand(2));
BuildMI(BB, PPC::ADDC, 2, Result).addReg(Tmp1).addReg(Tmp3); BuildMI(BB, PPC::ADDC, 2, Result).addReg(Tmp1).addReg(Tmp3);
}
// Codegen the high 32 bits, adding zero, minus one, or the full value // Codegen the high 32 bits, adding zero, minus one, or the full value
// along with the carry flag produced by addc/addic to tmp2. // along with the carry flag produced by addc/addic to tmp2.
if (ZE) if (ZE) {
BuildMI(BB, PPC::ADDZE, 1, Result+1).addReg(Tmp2); BuildMI(BB, PPC::ADDZE, 1, Result+1).addReg(Tmp2);
else if (ME) } else if (ME) {
BuildMI(BB, PPC::ADDME, 1, Result+1).addReg(Tmp2); BuildMI(BB, PPC::ADDME, 1, Result+1).addReg(Tmp2);
else } else {
BuildMI(BB, PPC::ADDE, 2, Result+1).addReg(Tmp2).addReg(Tmp4); BuildMI(BB, PPC::ADDE, 2, Result+1).addReg(Tmp2).addReg(Tmp4);
}
} else { } else {
Tmp3 = SelectExpr(N.getOperand(2));
Tmp4 = SelectExpr(N.getOperand(3));
BuildMI(BB, PPC::SUBFC, 2, Result).addReg(Tmp3).addReg(Tmp1); BuildMI(BB, PPC::SUBFC, 2, Result).addReg(Tmp3).addReg(Tmp1);
BuildMI(BB, PPC::SUBFE, 2, Result+1).addReg(Tmp4).addReg(Tmp2); BuildMI(BB, PPC::SUBFE, 2, Result+1).addReg(Tmp4).addReg(Tmp2);
} }