From 0d8314f6f36bf855820e1c7a816ddf75c5fa997d Mon Sep 17 00:00:00 2001 From: Matthias Braun Date: Tue, 7 Apr 2015 17:33:05 +0000 Subject: [PATCH] AArch64: Don't lower ISD::SELECT to ISD::SELECT_CC Instead of lowering SELECT to SELECT_CC which is further lowered later immediately call the SELECT_CC lowering code. This is preferable because: - Avoids an unnecessary roundtrip through the legalization queues with an intermediate node. - More importantly: Lowered operations get visited last leading to SELECT_CC getting visited with legalized operands and unlegalized ones for preexisting SELECT_CC nodes. This does not hurt the current code (hence no testcase) but is required for another patch I am working on. Differential Revision: http://reviews.llvm.org/D8187 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@234334 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/AArch64/AArch64ISelLowering.cpp | 101 ++++++++++++--------- lib/Target/AArch64/AArch64ISelLowering.h | 3 + 2 files changed, 60 insertions(+), 44 deletions(-) diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp index 0ddcf92aa8a..901e5b9a2c4 100644 --- a/lib/Target/AArch64/AArch64ISelLowering.cpp +++ b/lib/Target/AArch64/AArch64ISelLowering.cpp @@ -3515,49 +3515,10 @@ static bool selectCCOpsAreFMaxCompatible(SDValue Cmp, SDValue Result) { return Result->getOpcode() == ISD::FP_EXTEND && Result->getOperand(0) == Cmp; } -SDValue AArch64TargetLowering::LowerSELECT(SDValue Op, - SelectionDAG &DAG) const { - SDValue CC = Op->getOperand(0); - SDValue TVal = Op->getOperand(1); - SDValue FVal = Op->getOperand(2); - SDLoc DL(Op); - - unsigned Opc = CC.getOpcode(); - // Optimize {s|u}{add|sub|mul}.with.overflow feeding into a select - // instruction. - if (CC.getResNo() == 1 && - (Opc == ISD::SADDO || Opc == ISD::UADDO || Opc == ISD::SSUBO || - Opc == ISD::USUBO || Opc == ISD::SMULO || Opc == ISD::UMULO)) { - // Only lower legal XALUO ops. - if (!DAG.getTargetLoweringInfo().isTypeLegal(CC->getValueType(0))) - return SDValue(); - - AArch64CC::CondCode OFCC; - SDValue Value, Overflow; - std::tie(Value, Overflow) = getAArch64XALUOOp(OFCC, CC.getValue(0), DAG); - SDValue CCVal = DAG.getConstant(OFCC, MVT::i32); - - return DAG.getNode(AArch64ISD::CSEL, DL, Op.getValueType(), TVal, FVal, - CCVal, Overflow); - } - - if (CC.getOpcode() == ISD::SETCC) - return DAG.getSelectCC(DL, CC.getOperand(0), CC.getOperand(1), TVal, FVal, - cast(CC.getOperand(2))->get()); - else - return DAG.getSelectCC(DL, CC, DAG.getConstant(0, CC.getValueType()), TVal, - FVal, ISD::SETNE); -} - -SDValue AArch64TargetLowering::LowerSELECT_CC(SDValue Op, +SDValue AArch64TargetLowering::LowerSELECT_CC(ISD::CondCode CC, SDValue LHS, + SDValue RHS, SDValue TVal, + SDValue FVal, SDLoc dl, SelectionDAG &DAG) const { - ISD::CondCode CC = cast(Op.getOperand(4))->get(); - SDValue LHS = Op.getOperand(0); - SDValue RHS = Op.getOperand(1); - SDValue TVal = Op.getOperand(2); - SDValue FVal = Op.getOperand(3); - SDLoc dl(Op); - // Handle f128 first, because it will result in a comparison of some RTLIB // call result against zero. if (LHS.getValueType() == MVT::f128) { @@ -3665,14 +3626,14 @@ SDValue AArch64TargetLowering::LowerSELECT_CC(SDValue Op, SDValue CCVal; SDValue Cmp = getAArch64Cmp(LHS, RHS, CC, CCVal, DAG, dl); - EVT VT = Op.getValueType(); + EVT VT = TVal.getValueType(); return DAG.getNode(Opcode, dl, VT, TVal, FVal, CCVal, Cmp); } // Now we know we're dealing with FP values. assert(LHS.getValueType() == MVT::f32 || LHS.getValueType() == MVT::f64); assert(LHS.getValueType() == RHS.getValueType()); - EVT VT = Op.getValueType(); + EVT VT = TVal.getValueType(); // Try to match this select into a max/min operation, which have dedicated // opcode in the instruction set. @@ -3733,6 +3694,58 @@ SDValue AArch64TargetLowering::LowerSELECT_CC(SDValue Op, return CS1; } +SDValue AArch64TargetLowering::LowerSELECT_CC(SDValue Op, + SelectionDAG &DAG) const { + ISD::CondCode CC = cast(Op.getOperand(4))->get(); + SDValue LHS = Op.getOperand(0); + SDValue RHS = Op.getOperand(1); + SDValue TVal = Op.getOperand(2); + SDValue FVal = Op.getOperand(3); + SDLoc DL(Op); + return LowerSELECT_CC(CC, LHS, RHS, TVal, FVal, DL, DAG); +} + +SDValue AArch64TargetLowering::LowerSELECT(SDValue Op, + SelectionDAG &DAG) const { + SDValue CCVal = Op->getOperand(0); + SDValue TVal = Op->getOperand(1); + SDValue FVal = Op->getOperand(2); + SDLoc DL(Op); + + unsigned Opc = CCVal.getOpcode(); + // Optimize {s|u}{add|sub|mul}.with.overflow feeding into a select + // instruction. + if (CCVal.getResNo() == 1 && + (Opc == ISD::SADDO || Opc == ISD::UADDO || Opc == ISD::SSUBO || + Opc == ISD::USUBO || Opc == ISD::SMULO || Opc == ISD::UMULO)) { + // Only lower legal XALUO ops. + if (!DAG.getTargetLoweringInfo().isTypeLegal(CCVal->getValueType(0))) + return SDValue(); + + AArch64CC::CondCode OFCC; + SDValue Value, Overflow; + std::tie(Value, Overflow) = getAArch64XALUOOp(OFCC, CCVal.getValue(0), DAG); + SDValue CCVal = DAG.getConstant(OFCC, MVT::i32); + + return DAG.getNode(AArch64ISD::CSEL, DL, Op.getValueType(), TVal, FVal, + CCVal, Overflow); + } + + // Lower it the same way as we would lower a SELECT_CC node. + ISD::CondCode CC; + SDValue LHS, RHS; + if (CCVal.getOpcode() == ISD::SETCC) { + LHS = CCVal.getOperand(0); + RHS = CCVal.getOperand(1); + CC = cast(CCVal->getOperand(2))->get(); + } else { + LHS = CCVal; + RHS = DAG.getConstant(0, CCVal.getValueType()); + CC = ISD::SETNE; + } + return LowerSELECT_CC(CC, LHS, RHS, TVal, FVal, DL, DAG); +} + SDValue AArch64TargetLowering::LowerJumpTable(SDValue Op, SelectionDAG &DAG) const { // Jump table entries as PC relative offsets. No additional tweaking diff --git a/lib/Target/AArch64/AArch64ISelLowering.h b/lib/Target/AArch64/AArch64ISelLowering.h index 4a61b9e9527..820613b917d 100644 --- a/lib/Target/AArch64/AArch64ISelLowering.h +++ b/lib/Target/AArch64/AArch64ISelLowering.h @@ -420,6 +420,9 @@ private: SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const; SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const; SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const; + SDValue LowerSELECT_CC(ISD::CondCode CC, SDValue LHS, SDValue RHS, + SDValue TVal, SDValue FVal, SDLoc dl, + SelectionDAG &DAG) const; SDValue LowerJumpTable(SDValue Op, SelectionDAG &DAG) const; SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const; SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;