[llvm] r245198 - Remove hand-rolled matching for fmin and fmax.
James Molloy via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 18 12:51:46 PDT 2015
Hi Ahmed,
I'm afraid I'm not quite certain what you mean - could you elaborate?
Cheers,
James
On 18 Aug 2015, at 19:36, Ahmed Bougacha <ahmed.bougacha at gmail.com<mailto:ahmed.bougacha at gmail.com>> wrote:
Hey James,
If I read this correctly, we can't fold fpext anymore, right? Not a big deal right now, as the main case where I see this being useful is a promoted f16 min/max, and that's not even caught currently.
Do you think we should do something similar in the builder? If so, let's file a PR!
-Ahmed
On Mon, Aug 17, 2015 at 12:13 AM, James Molloy via llvm-commits <llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>> wrote:
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:
_______________________________________________
llvm-commits mailing list
llvm-commits at lists.llvm.org<mailto:llvm-commits at lists.llvm.org>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
-- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2557590
ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2548782
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150818/a62e1744/attachment.html>
More information about the llvm-commits
mailing list