diff options
Diffstat (limited to 'llvm/lib/Target')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 74 |
1 files changed, 36 insertions, 38 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index e827c5c35f1..7dcdb796705 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -33928,45 +33928,43 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG, "Both cases that could cause potential overflows should have " "already been handled."); int64_t SignMulAmt = C->getSExtValue(); - if ((SignMulAmt != INT64_MIN) && (SignMulAmt != INT64_MAX) && - (SignMulAmt != -INT64_MAX)) { - int64_t AbsMulAmt = SignMulAmt < 0 ? -SignMulAmt : SignMulAmt; - if (isPowerOf2_64(AbsMulAmt - 1)) { - // (mul x, 2^N + 1) => (add (shl x, N), x) - NewMul = DAG.getNode( - ISD::ADD, DL, VT, N->getOperand(0), - DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(Log2_64(AbsMulAmt - 1), DL, - MVT::i8))); - // To negate, subtract the number from zero - if (SignMulAmt < 0) - NewMul = DAG.getNode(ISD::SUB, DL, VT, - DAG.getConstant(0, DL, VT), NewMul); - } else if (isPowerOf2_64(AbsMulAmt + 1)) { - // (mul x, 2^N - 1) => (sub (shl x, N), x) - NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(Log2_64(AbsMulAmt + 1), - DL, MVT::i8)); - // To negate, reverse the operands of the subtract. - if (SignMulAmt < 0) - NewMul = DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), NewMul); - else - NewMul = DAG.getNode(ISD::SUB, DL, VT, NewMul, N->getOperand(0)); - } else if (SignMulAmt >= 0 && isPowerOf2_64(AbsMulAmt - 2)) { - // (mul x, 2^N + 2) => (add (add (shl x, N), x), x) - NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(Log2_64(AbsMulAmt - 2), - DL, MVT::i8)); - NewMul = DAG.getNode(ISD::ADD, DL, VT, NewMul, N->getOperand(0)); - NewMul = DAG.getNode(ISD::ADD, DL, VT, NewMul, N->getOperand(0)); - } else if (SignMulAmt >= 0 && isPowerOf2_64(AbsMulAmt + 2)) { - // (mul x, 2^N - 2) => (sub (sub (shl x, N), x), x) - NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(Log2_64(AbsMulAmt + 2), - DL, MVT::i8)); - NewMul = DAG.getNode(ISD::SUB, DL, VT, NewMul, N->getOperand(0)); + 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( + ISD::ADD, DL, VT, N->getOperand(0), + DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), + DAG.getConstant(Log2_64(AbsMulAmt - 1), DL, + MVT::i8))); + // To negate, subtract the number from zero + if (SignMulAmt < 0) + NewMul = DAG.getNode(ISD::SUB, DL, VT, + DAG.getConstant(0, DL, VT), NewMul); + } else if (isPowerOf2_64(AbsMulAmt + 1)) { + // (mul x, 2^N - 1) => (sub (shl x, N), x) + NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), + DAG.getConstant(Log2_64(AbsMulAmt + 1), + DL, MVT::i8)); + // To negate, reverse the operands of the subtract. + if (SignMulAmt < 0) + NewMul = DAG.getNode(ISD::SUB, DL, VT, N->getOperand(0), NewMul); + else NewMul = DAG.getNode(ISD::SUB, DL, VT, NewMul, N->getOperand(0)); - } + } else if (SignMulAmt >= 0 && isPowerOf2_64(AbsMulAmt - 2)) { + // (mul x, 2^N + 2) => (add (add (shl x, N), x), x) + NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), + DAG.getConstant(Log2_64(AbsMulAmt - 2), + DL, MVT::i8)); + NewMul = DAG.getNode(ISD::ADD, DL, VT, NewMul, N->getOperand(0)); + NewMul = DAG.getNode(ISD::ADD, DL, VT, NewMul, N->getOperand(0)); + } else if (SignMulAmt >= 0 && isPowerOf2_64(AbsMulAmt + 2)) { + // (mul x, 2^N - 2) => (sub (sub (shl x, N), x), x) + NewMul = DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), + DAG.getConstant(Log2_64(AbsMulAmt + 2), + DL, MVT::i8)); + NewMul = DAG.getNode(ISD::SUB, DL, VT, NewMul, N->getOperand(0)); + NewMul = DAG.getNode(ISD::SUB, DL, VT, NewMul, N->getOperand(0)); } } |
