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For targets with FABS/FNEG support, lower copysign to an integer load,

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a select and FABS/FNEG.

This speeds up a trivial (aka stupid) copysign benchmark I wrote from 6.73s
to 2.64s, woo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26723 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-03-13 06:08:38 +00:00
parent 64ce964673
commit 8f4191d619
1 changed files with 25 additions and 2 deletions
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27
lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
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@ -1795,10 +1795,33 @@ SDOperand SelectionDAGLegalize::LegalizeOp(SDOperand Op) {
case TargetLowering::Custom: case TargetLowering::Custom:
Tmp1 = TLI.LowerOperation(Result, DAG); Tmp1 = TLI.LowerOperation(Result, DAG);
if (Tmp1.Val) Result = Tmp1; if (Tmp1.Val) Result = Tmp1;
break; break;
case TargetLowering::Legal: break; case TargetLowering::Legal: break;
case TargetLowering::Expand: case TargetLowering::Expand:
// Floating point mod -> fmod libcall. // If this target supports fabs/fneg natively, do this efficiently.
if (TLI.isOperationLegal(ISD::FABS, Tmp1.getValueType()) &&
TLI.isOperationLegal(ISD::FNEG, Tmp1.getValueType())) {
// Get the sign bit of the RHS.
MVT::ValueType IVT =
Tmp2.getValueType() == MVT::f32 ? MVT::i32 : MVT::i64;
SDOperand SignBit = DAG.getNode(ISD::BIT_CONVERT, IVT, Tmp2);
SignBit = DAG.getSetCC(TLI.getSetCCResultTy(),
SignBit, DAG.getConstant(0, IVT), ISD::SETLT);
// Get the absolute value of the result.
SDOperand AbsVal = DAG.getNode(ISD::FABS, Tmp1.getValueType(), Tmp1);
// Select between the nabs and abs value based on the sign bit of
// the input.
Result = DAG.getNode(ISD::SELECT, AbsVal.getValueType(), SignBit,
DAG.getNode(ISD::FNEG, AbsVal.getValueType(),
AbsVal),
AbsVal);
Result = LegalizeOp(Result);
break;
}
// Otherwise, do bitwise ops!
// copysign -> copysignf/copysign libcall.
const char *FnName; const char *FnName;
if (Node->getValueType(0) == MVT::f32) { if (Node->getValueType(0) == MVT::f32) {
FnName = "copysignf"; FnName = "copysignf";