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canonicalize a bunch of operations involving fneg

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21160 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-04-09 03:02:46 +00:00
parent a9532d5dde
commit 485df9b84b
1 changed files with 21 additions and 0 deletions

21
lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@ -565,6 +565,8 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Operand.Val))
switch (Opcode) {
case ISD::FNEG:
return getConstantFP(-C->getValue(), VT);
case ISD::FP_ROUND:
case ISD::FP_EXTEND:
return getConstantFP(C->getValue(), VT);
@ -602,6 +604,17 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
return Operand.Val->getOperand(0);
}
break;
case ISD::FNEG:
if (OpOpcode == ISD::SUB) // -(X-Y) -> (Y-X)
return getNode(ISD::SUB, VT, Operand.Val->getOperand(1),
Operand.Val->getOperand(0));
if (OpOpcode == ISD::FNEG) // --X -> X
return Operand.Val->getOperand(0);
break;
case ISD::FABS:
if (OpOpcode == ISD::FNEG) // abs(-X) -> abs(X)
return getNode(ISD::FABS, VT, Operand.Val->getOperand(0));
break;
}
SDNode *&N = UnaryOps[std::make_pair(Opcode, std::make_pair(Operand, VT))];
@ -859,6 +872,12 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
case ISD::XOR:
if (N1 == N2) return getConstant(0, VT); // xor X, Y -> 0
break;
case ISD::ADD:
if (N2.getOpcode() == ISD::FNEG) // (A+ (-B) -> A-B
return getNode(ISD::SUB, VT, N1, N2.getOperand(0));
if (N1.getOpcode() == ISD::FNEG) // ((-A)+B) -> B-A
return getNode(ISD::SUB, VT, N2, N1.getOperand(0));
break;
case ISD::SUB:
if (N1.getOpcode() == ISD::ADD) {
if (N1.Val->getOperand(0) == N2)
@ -866,6 +885,8 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if (N1.Val->getOperand(1) == N2)
return N1.Val->getOperand(0); // (A+B)-B == A
}
if (N2.getOpcode() == ISD::FNEG) // (A- (-B) -> A+B
return getNode(ISD::ADD, VT, N1, N2.getOperand(0));
break;
}