diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 67 |
1 files changed, 45 insertions, 22 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index e2862f6200c..c7b383a8be4 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -30939,11 +30939,40 @@ static bool checkBoolTestAndOrSetCCCombine(SDValue Cond, X86::CondCode &CC0, return true; } +// When legalizing carry, we create carries via add X, -1 +// If that comes from an actual carry, via setcc, we use the +// carry directly. +static SDValue combineCarryThroughADD(SDValue EFLAGS) { + if (EFLAGS.getOpcode() == X86ISD::ADD) { + if (isAllOnesConstant(EFLAGS.getOperand(1))) { + SDValue Carry = EFLAGS.getOperand(0); + while (Carry.getOpcode() == ISD::TRUNCATE || + Carry.getOpcode() == ISD::ZERO_EXTEND || + Carry.getOpcode() == ISD::SIGN_EXTEND || + Carry.getOpcode() == ISD::ANY_EXTEND || + (Carry.getOpcode() == ISD::AND && + isOneConstant(Carry.getOperand(1)))) + Carry = Carry.getOperand(0); + if (Carry.getOpcode() == X86ISD::SETCC || + Carry.getOpcode() == X86ISD::SETCC_CARRY) { + if (Carry.getConstantOperandVal(0) == X86::COND_B) + return Carry.getOperand(1); + } + } + } + + return SDValue(); +} + /// Optimize an EFLAGS definition used according to the condition code \p CC /// into a simpler EFLAGS value, potentially returning a new \p CC and replacing /// uses of chain values. static SDValue combineSetCCEFLAGS(SDValue EFLAGS, X86::CondCode &CC, SelectionDAG &DAG) { + if (CC == X86::COND_B) + if (SDValue Flags = combineCarryThroughADD(EFLAGS)) + return Flags; + if (SDValue R = checkBoolTestSetCCCombine(EFLAGS, CC)) return R; return combineSetCCAtomicArith(EFLAGS, CC, DAG); @@ -34987,27 +35016,13 @@ static SDValue combineSIntToFP(SDNode *N, SelectionDAG &DAG, return SDValue(); } -// Optimize RES, EFLAGS = X86ISD::ADD LHS, RHS -static SDValue combineX86ADD(SDNode *N, SelectionDAG &DAG, - X86TargetLowering::DAGCombinerInfo &DCI) { - // When legalizing carry, we create carries via add X, -1 - // If that comes from an actual carry, via setcc, we use the - // carry directly. - if (isAllOnesConstant(N->getOperand(1)) && N->hasAnyUseOfValue(1)) { - SDValue Carry = N->getOperand(0); - while (Carry.getOpcode() == ISD::TRUNCATE || - Carry.getOpcode() == ISD::ZERO_EXTEND || - Carry.getOpcode() == ISD::SIGN_EXTEND || - Carry.getOpcode() == ISD::ANY_EXTEND || - (Carry.getOpcode() == ISD::AND && - isOneConstant(Carry.getOperand(1)))) - Carry = Carry.getOperand(0); - - if (Carry.getOpcode() == X86ISD::SETCC || - Carry.getOpcode() == X86ISD::SETCC_CARRY) { - if (Carry.getConstantOperandVal(0) == X86::COND_B) - return DCI.CombineTo(N, SDValue(N, 0), Carry.getOperand(1)); - } +static SDValue combineSBB(SDNode *N, SelectionDAG &DAG) { + if (SDValue Flags = combineCarryThroughADD(N->getOperand(2))) { + MVT VT = N->getSimpleValueType(0); + SDVTList VTs = DAG.getVTList(VT, MVT::i32); + return DAG.getNode(X86ISD::SBB, SDLoc(N), VTs, + N->getOperand(0), N->getOperand(1), + Flags); } return SDValue(); @@ -35036,6 +35051,14 @@ static SDValue combineADC(SDNode *N, SelectionDAG &DAG, return DCI.CombineTo(N, Res1, CarryOut); } + if (SDValue Flags = combineCarryThroughADD(N->getOperand(2))) { + MVT VT = N->getSimpleValueType(0); + SDVTList VTs = DAG.getVTList(VT, MVT::i32); + return DAG.getNode(X86ISD::ADC, SDLoc(N), VTs, + N->getOperand(0), N->getOperand(1), + Flags); + } + return SDValue(); } @@ -35721,7 +35744,7 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N, case X86ISD::CMOV: return combineCMov(N, DAG, DCI, Subtarget); case ISD::ADD: return combineAdd(N, DAG, Subtarget); case ISD::SUB: return combineSub(N, DAG, Subtarget); - case X86ISD::ADD: return combineX86ADD(N, DAG, DCI); + case X86ISD::SBB: return combineSBB(N, DAG); case X86ISD::ADC: return combineADC(N, DAG, DCI); case ISD::MUL: return combineMul(N, DAG, DCI, Subtarget); case ISD::SHL: |
