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R600/SI: implement range reduction for sin/cos

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These instructions can only take a limited input range, and return
the constant value 1 out of range. We should do range reduction to
be able to process arbitrary values. Use a FRACT instruction after
normalization to achieve this. Also add a test for constant folding
with the lowered code with unsafe-fp-math enabled.

v2: use DAG lowering instead of intrinsic, adapt test
v3: calculate constant, fold pattern into instruction definition
v4: misc style fixes, add sin-fold testcase, cosmetics

Patch by Grigori Goronzy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213458 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matt Arsenault
2014-07-19 18:44:39 +00:00
parent 5e1c96a632
commit 18ecf3fff3
5 changed files with 53 additions and 14 deletions
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23
lib/Target/R600/SIISelLowering.cpp
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@@ -80,6 +80,9 @@ SITargetLowering::SITargetLowering(TargetMachine &TM) :
setOperationAction(ISD::SUBC, MVT::i32, Legal);
setOperationAction(ISD::SUBE, MVT::i32, Legal);
setOperationAction(ISD::FSIN, MVT::f32, Custom);
setOperationAction(ISD::FCOS, MVT::f32, Custom);
// We need to custom lower vector stores from local memory
setOperationAction(ISD::LOAD, MVT::v2i32, Custom);
setOperationAction(ISD::LOAD, MVT::v4i32, Custom);
@@ -637,6 +640,9 @@ SDValue SITargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
}
}
case ISD::FSIN:
case ISD::FCOS:
return LowerTrig(Op, DAG);
case ISD::SELECT: return LowerSELECT(Op, DAG);
case ISD::FDIV: return LowerFDIV(Op, DAG);
case ISD::STORE: return LowerSTORE(Op, DAG);
@@ -1116,6 +1122,23 @@ SDValue SITargetLowering::LowerSTORE(SDValue Op, SelectionDAG &DAG) const {
return Chain;
}
SDValue SITargetLowering::LowerTrig(SDValue Op, SelectionDAG &DAG) const {
EVT VT = Op.getValueType();
SDValue Arg = Op.getOperand(0);
SDValue FractPart = DAG.getNode(AMDGPUISD::FRACT, SDLoc(Op), VT,
DAG.getNode(ISD::FMUL, SDLoc(Op), VT, Arg,
DAG.getConstantFP(0.5 / M_PI, VT)));
switch (Op.getOpcode()) {
case ISD::FCOS:
return DAG.getNode(AMDGPUISD::COS_HW, SDLoc(Op), VT, FractPart);
case ISD::FSIN:
return DAG.getNode(AMDGPUISD::SIN_HW, SDLoc(Op), VT, FractPart);
default:
llvm_unreachable("Wrong trig opcode");
}
}
//===----------------------------------------------------------------------===//
// Custom DAG optimizations
//===----------------------------------------------------------------------===//