[llvm] r245198 - Remove hand-rolled matching for fmin and fmax.
James Molloy via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 17 00:13:20 PDT 2015
Author: jamesm
Date: Mon Aug 17 02:13:20 2015
New Revision: 245198
URL: http://llvm.org/viewvc/llvm-project?rev=245198&view=rev
Log:
Remove hand-rolled matching for fmin and fmax.
SDAGBuilder now does this all for us.
Modified:
llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
Modified: llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp?rev=245198&r1=245197&r2=245198&view=diff
==============================================================================
--- llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/AArch64/AArch64ISelLowering.cpp Mon Aug 17 02:13:20 2015
@@ -393,6 +393,8 @@ AArch64TargetLowering::AArch64TargetLowe
setOperationAction(ISD::FROUND, Ty, Legal);
setOperationAction(ISD::FMINNUM, Ty, Legal);
setOperationAction(ISD::FMAXNUM, Ty, Legal);
+ setOperationAction(ISD::FMINNAN, Ty, Legal);
+ setOperationAction(ISD::FMAXNAN, Ty, Legal);
}
setOperationAction(ISD::PREFETCH, MVT::Other, Custom);
@@ -484,7 +486,6 @@ AArch64TargetLowering::AArch64TargetLowe
setTargetDAGCombine(ISD::SELECT);
setTargetDAGCombine(ISD::VSELECT);
- setTargetDAGCombine(ISD::SELECT_CC);
setTargetDAGCombine(ISD::INTRINSIC_VOID);
setTargetDAGCombine(ISD::INTRINSIC_W_CHAIN);
@@ -3826,32 +3827,6 @@ SDValue AArch64TargetLowering::LowerSETC
}
}
-/// A SELECT_CC operation is really some kind of max or min if both values being
-/// compared are, in some sense, equal to the results in either case. However,
-/// it is permissible to compare f32 values and produce directly extended f64
-/// values.
-///
-/// Extending the comparison operands would also be allowed, but is less likely
-/// to happen in practice since their use is right here. Note that truncate
-/// operations would *not* be semantically equivalent.
-static bool selectCCOpsAreFMaxCompatible(SDValue Cmp, SDValue Result) {
- if (Cmp == Result)
- return (Cmp.getValueType() == MVT::f32 ||
- Cmp.getValueType() == MVT::f64);
-
- ConstantFPSDNode *CCmp = dyn_cast<ConstantFPSDNode>(Cmp);
- ConstantFPSDNode *CResult = dyn_cast<ConstantFPSDNode>(Result);
- if (CCmp && CResult && Cmp.getValueType() == MVT::f32 &&
- Result.getValueType() == MVT::f64) {
- bool Lossy;
- APFloat CmpVal = CCmp->getValueAPF();
- CmpVal.convert(APFloat::IEEEdouble, APFloat::rmNearestTiesToEven, &Lossy);
- return CResult->getValueAPF().bitwiseIsEqual(CmpVal);
- }
-
- return Result->getOpcode() == ISD::FP_EXTEND && Result->getOperand(0) == Cmp;
-}
-
SDValue AArch64TargetLowering::LowerSELECT_CC(ISD::CondCode CC, SDValue LHS,
SDValue RHS, SDValue TVal,
SDValue FVal, SDLoc dl,
@@ -9124,75 +9099,6 @@ static SDValue performSelectCombine(SDNo
return DAG.getSelect(DL, ResVT, Mask, N->getOperand(1), N->getOperand(2));
}
-/// performSelectCCCombine - Target-specific DAG combining for ISD::SELECT_CC
-/// to match FMIN/FMAX patterns.
-static SDValue performSelectCCCombine(SDNode *N, SelectionDAG &DAG) {
- // Try to use FMIN/FMAX instructions for FP selects like "x < y ? x : y".
- // Unless the NoNaNsFPMath option is set, be careful about NaNs:
- // vmax/vmin return NaN if either operand is a NaN;
- // only do the transformation when it matches that behavior.
-
- SDValue CondLHS = N->getOperand(0);
- SDValue CondRHS = N->getOperand(1);
- SDValue LHS = N->getOperand(2);
- SDValue RHS = N->getOperand(3);
- ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(4))->get();
-
- unsigned Opcode;
- bool IsReversed;
- if (selectCCOpsAreFMaxCompatible(CondLHS, LHS) &&
- selectCCOpsAreFMaxCompatible(CondRHS, RHS)) {
- IsReversed = false; // x CC y ? x : y
- } else if (selectCCOpsAreFMaxCompatible(CondRHS, LHS) &&
- selectCCOpsAreFMaxCompatible(CondLHS, RHS)) {
- IsReversed = true ; // x CC y ? y : x
- } else {
- return SDValue();
- }
-
- bool IsUnordered = false, IsOrEqual;
- switch (CC) {
- default:
- return SDValue();
- case ISD::SETULT:
- case ISD::SETULE:
- IsUnordered = true;
- case ISD::SETOLT:
- case ISD::SETOLE:
- case ISD::SETLT:
- case ISD::SETLE:
- IsOrEqual = (CC == ISD::SETLE || CC == ISD::SETOLE || CC == ISD::SETULE);
- Opcode = IsReversed ? ISD::FMAXNAN : ISD::FMINNAN;
- break;
-
- case ISD::SETUGT:
- case ISD::SETUGE:
- IsUnordered = true;
- case ISD::SETOGT:
- case ISD::SETOGE:
- case ISD::SETGT:
- case ISD::SETGE:
- IsOrEqual = (CC == ISD::SETGE || CC == ISD::SETOGE || CC == ISD::SETUGE);
- Opcode = IsReversed ? ISD::FMINNAN : ISD::FMAXNAN;
- break;
- }
-
- // If LHS is NaN, an ordered comparison will be false and the result will be
- // the RHS, but FMIN(NaN, RHS) = FMAX(NaN, RHS) = NaN. Avoid this by checking
- // that LHS != NaN. Likewise, for unordered comparisons, check for RHS != NaN.
- if (!DAG.isKnownNeverNaN(IsUnordered ? RHS : LHS))
- return SDValue();
-
- // For xxx-or-equal comparisons, "+0 <= -0" and "-0 >= +0" will both be true,
- // but FMIN will return -0, and FMAX will return +0. So FMIN/FMAX can only be
- // used for unsafe math or if one of the operands is known to be nonzero.
- if (IsOrEqual && !DAG.getTarget().Options.UnsafeFPMath &&
- !(DAG.isKnownNeverZero(LHS) || DAG.isKnownNeverZero(RHS)))
- return SDValue();
-
- return DAG.getNode(Opcode, SDLoc(N), N->getValueType(0), LHS, RHS);
-}
-
/// Get rid of unnecessary NVCASTs (that don't change the type).
static SDValue performNVCASTCombine(SDNode *N) {
if (N->getValueType(0) == N->getOperand(0).getValueType())
@@ -9233,8 +9139,6 @@ SDValue AArch64TargetLowering::PerformDA
return performSelectCombine(N, DCI);
case ISD::VSELECT:
return performVSelectCombine(N, DCI.DAG);
- case ISD::SELECT_CC:
- return performSelectCCCombine(N, DCI.DAG);
case ISD::STORE:
return performSTORECombine(N, DCI, DAG, Subtarget);
case AArch64ISD::BRCOND:
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