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Add some simple copysign folds 

llvm-svn: 26543
This commit is contained in:
Chris Lattner 2006-03-05 05:30:57 +00:00
parent 5c1ba2ac08
commit 3bc4050217
2 changed files with 61 additions and 7 deletions
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66
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -195,6 +195,7 @@ namespace {
SDOperand visitFMUL(SDNode *N);
SDOperand visitFDIV(SDNode *N);
SDOperand visitFREM(SDNode *N);
SDOperand visitFCOPYSIGN(SDNode *N);
SDOperand visitSINT_TO_FP(SDNode *N);
SDOperand visitUINT_TO_FP(SDNode *N);
SDOperand visitFP_TO_SINT(SDNode *N);
@ -627,6 +628,7 @@ SDOperand DAGCombiner::visit(SDNode *N) {
case ISD::FMUL: return visitFMUL(N);
case ISD::FDIV: return visitFDIV(N);
case ISD::FREM: return visitFREM(N);
case ISD::FCOPYSIGN: return visitFCOPYSIGN(N);
case ISD::SINT_TO_FP: return visitSINT_TO_FP(N);
case ISD::UINT_TO_FP: return visitUINT_TO_FP(N);
case ISD::FP_TO_SINT: return visitFP_TO_SINT(N);
@ -1999,6 +2001,54 @@ SDOperand DAGCombiner::visitFREM(SDNode *N) {
return SDOperand();
}
SDOperand DAGCombiner::visitFCOPYSIGN(SDNode *N) {
SDOperand N0 = N->getOperand(0);
SDOperand N1 = N->getOperand(1);
ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
ConstantFPSDNode *N1CFP = dyn_cast<ConstantFPSDNode>(N1);
MVT::ValueType VT = N->getValueType(0);
if (N0CFP && N1CFP) // Constant fold
return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1);
if (N1CFP) {
// copysign(x, c1) -> fabs(x) iff ispos(c1)
// copysign(x, c1) -> fneg(fabs(x)) iff isneg(c1)
union {
double d;
int64_t i;
} u;
u.d = N1CFP->getValue();
if (u.i >= 0)
return DAG.getNode(ISD::FABS, VT, N0);
else
return DAG.getNode(ISD::FNEG, VT, DAG.getNode(ISD::FABS, VT, N0));
}
// copysign(fabs(x), y) -> copysign(x, y)
// copysign(fneg(x), y) -> copysign(x, y)
// copysign(copysign(x,z), y) -> copysign(x, y)
if (N0.getOpcode() == ISD::FABS || N0.getOpcode() == ISD::FNEG ||
N0.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FCOPYSIGN, VT, N0.getOperand(0), N1);
// copysign(x, abs(y)) -> abs(x)
if (N1.getOpcode() == ISD::FABS)
return DAG.getNode(ISD::FABS, VT, N0);
// copysign(x, copysign(y,z)) -> copysign(x, z)
if (N1.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(1));
// copysign(x, fp_extend(y)) -> copysign(x, y)
// copysign(x, fp_round(y)) -> copysign(x, y)
if (N1.getOpcode() == ISD::FP_EXTEND || N1.getOpcode() == ISD::FP_ROUND)
return DAG.getNode(ISD::FCOPYSIGN, VT, N0, N1.getOperand(0));
return SDOperand();
}
SDOperand DAGCombiner::visitSINT_TO_FP(SDNode *N) {
SDOperand N0 = N->getOperand(0);
@ -2089,11 +2139,11 @@ SDOperand DAGCombiner::visitFNEG(SDNode *N) {
if (N0CFP)
return DAG.getNode(ISD::FNEG, VT, N0);
// fold (fneg (sub x, y)) -> (sub y, x)
if (N->getOperand(0).getOpcode() == ISD::SUB)
return DAG.getNode(ISD::SUB, VT, N->getOperand(1), N->getOperand(0));
if (N0.getOpcode() == ISD::SUB)
return DAG.getNode(ISD::SUB, VT, N0.getOperand(1), N0.getOperand(0));
// fold (fneg (fneg x)) -> x
if (N->getOperand(0).getOpcode() == ISD::FNEG)
return N->getOperand(0).getOperand(0);
if (N0.getOpcode() == ISD::FNEG)
return N0.getOperand(0);
return SDOperand();
}
@ -2106,11 +2156,13 @@ SDOperand DAGCombiner::visitFABS(SDNode *N) {
if (N0CFP)
return DAG.getNode(ISD::FABS, VT, N0);
// fold (fabs (fabs x)) -> (fabs x)
if (N->getOperand(0).getOpcode() == ISD::FABS)
if (N0.getOpcode() == ISD::FABS)
return N->getOperand(0);
// fold (fabs (fneg x)) -> (fabs x)
if (N->getOperand(0).getOpcode() == ISD::FNEG)
return DAG.getNode(ISD::FABS, VT, N->getOperand(0).getOperand(0));
// fold (fabs (fcopysign x, y)) -> (fabs x)
if (N0.getOpcode() == ISD::FNEG || N0.getOpcode() == ISD::FCOPYSIGN)
return DAG.getNode(ISD::FABS, VT, N0.getOperand(0));
return SDOperand();
}

2
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -1250,6 +1250,8 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
case ISD::FREM :
if (C2) return getConstantFP(fmod(C1, C2), VT);
break;
case ISD::FCOPYSIGN:
return getConstantFP(copysign(C1, C2), VT);
default: break;
}
} else { // Cannonicalize constant to RHS if commutative