diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 49 |
1 files changed, 31 insertions, 18 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 7dcdb796705..d91d23f0529 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -33873,31 +33873,42 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG, ConstantSDNode *C = dyn_cast<ConstantSDNode>(N->getOperand(1)); if (!C) return SDValue(); - uint64_t MulAmt = C->getZExtValue(); - if (isPowerOf2_64(MulAmt)) + if (isPowerOf2_64(C->getZExtValue())) return SDValue(); + int64_t SignMulAmt = C->getSExtValue(); + assert(SignMulAmt != INT64_MIN && "Int min should have been handled!"); + uint64_t AbsMulAmt = SignMulAmt < 0 ? -SignMulAmt : SignMulAmt; + SDLoc DL(N); - if (MulAmt == 3 || MulAmt == 5 || MulAmt == 9) - return DAG.getNode(X86ISD::MUL_IMM, DL, VT, N->getOperand(0), - N->getOperand(1)); + if (AbsMulAmt == 3 || AbsMulAmt == 5 || AbsMulAmt == 9) { + SDValue NewMul = DAG.getNode(X86ISD::MUL_IMM, DL, VT, N->getOperand(0), + DAG.getConstant(AbsMulAmt, DL, VT)); + if (SignMulAmt < 0) + NewMul = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), + NewMul); + + return NewMul; + } uint64_t MulAmt1 = 0; uint64_t MulAmt2 = 0; - if ((MulAmt % 9) == 0) { + if ((AbsMulAmt % 9) == 0) { MulAmt1 = 9; - MulAmt2 = MulAmt / 9; - } else if ((MulAmt % 5) == 0) { + MulAmt2 = AbsMulAmt / 9; + } else if ((AbsMulAmt % 5) == 0) { MulAmt1 = 5; - MulAmt2 = MulAmt / 5; - } else if ((MulAmt % 3) == 0) { + MulAmt2 = AbsMulAmt / 5; + } else if ((AbsMulAmt % 3) == 0) { MulAmt1 = 3; - MulAmt2 = MulAmt / 3; + MulAmt2 = AbsMulAmt / 3; } SDValue NewMul; + // For negative multiply amounts, only allow MulAmt2 to be a power of 2. if (MulAmt2 && - (isPowerOf2_64(MulAmt2) || MulAmt2 == 3 || MulAmt2 == 5 || MulAmt2 == 9)){ + (isPowerOf2_64(MulAmt2) || + (SignMulAmt >= 0 && (MulAmt2 == 3 || MulAmt2 == 5 || MulAmt2 == 9)))) { if (isPowerOf2_64(MulAmt2) && !(N->hasOneUse() && N->use_begin()->getOpcode() == ISD::ADD)) @@ -33919,17 +33930,19 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG, else NewMul = DAG.getNode(X86ISD::MUL_IMM, DL, VT, NewMul, DAG.getConstant(MulAmt2, DL, VT)); + + // Negate the result. + if (SignMulAmt < 0) + NewMul = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), + NewMul); } else if (!Subtarget.slowLEA()) - NewMul = combineMulSpecial(MulAmt, N, DAG, VT, DL); + NewMul = combineMulSpecial(C->getZExtValue(), N, DAG, VT, DL); if (!NewMul) { - assert(MulAmt != 0 && - MulAmt != (VT == MVT::i64 ? UINT64_MAX : UINT32_MAX) && + assert(C->getZExtValue() != 0 && + C->getZExtValue() != (VT == MVT::i64 ? UINT64_MAX : UINT32_MAX) && "Both cases that could cause potential overflows should have " "already been handled."); - int64_t SignMulAmt = C->getSExtValue(); - assert(SignMulAmt != INT64_MIN && "Int min should have been handled!"); - uint64_t AbsMulAmt = SignMulAmt < 0 ? -SignMulAmt : SignMulAmt; if (isPowerOf2_64(AbsMulAmt - 1)) { // (mul x, 2^N + 1) => (add (shl x, N), x) NewMul = DAG.getNode( |
