diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelLowering.cpp | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index 6f7636c619d..ef8a6d68395 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -33727,12 +33727,8 @@ static SDValue combineMulSpecial(uint64_t MulAmt, SDNode *N, SelectionDAG &DAG, // mul x, 13 => add ((shl (mul x, 3), 2), x) return combineMulShlAddOrSub(3, 2, /*isAdd*/ true); case 23: - // mul x, 13 => sub ((shl (mul x, 3), 3), x) + // mul x, 23 => sub ((shl (mul x, 3), 3), x) return combineMulShlAddOrSub(3, 3, /*isAdd*/ false); - case 14: - // mul x, 14 => add (add ((shl (mul x, 3), 2), x), x) - return DAG.getNode(ISD::ADD, DL, VT, N->getOperand(0), - combineMulShlAddOrSub(3, 2, /*isAdd*/ true)); case 26: // mul x, 26 => sub ((mul (mul x, 9), 3), x) return combineMulMulAddOrSub(/*isAdd*/ false); @@ -33743,15 +33739,6 @@ static SDValue combineMulSpecial(uint64_t MulAmt, SDNode *N, SelectionDAG &DAG, // mul x, 29 => add (add ((mul (mul x, 9), 3), x), x) return DAG.getNode(ISD::ADD, DL, VT, N->getOperand(0), combineMulMulAddOrSub(/*isAdd*/ true)); - case 30: - // mul x, 30 => sub (sub ((shl x, 5), x), x) - return DAG.getNode( - ISD::SUB, DL, VT, - DAG.getNode(ISD::SUB, DL, VT, - DAG.getNode(ISD::SHL, DL, VT, N->getOperand(0), - DAG.getConstant(5, DL, MVT::i8)), - N->getOperand(0)), - N->getOperand(0)); } return SDValue(); } @@ -33927,6 +33914,7 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG, int NumSign = SignMulAmt > 0 ? 1 : -1; bool IsPowerOf2_64PlusOne = isPowerOf2_64(NumSign * SignMulAmt - 1); bool IsPowerOf2_64MinusOne = isPowerOf2_64(NumSign * SignMulAmt + 1); + bool IsPowerOf2_64MinusTwo = isPowerOf2_64(NumSign * SignMulAmt + 2); if (IsPowerOf2_64PlusOne) { // (mul x, 2^N + 1) => (add (shl x, N), x) NewMul = DAG.getNode( @@ -33942,9 +33930,16 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG, DAG.getConstant(Log2_64(NumSign * SignMulAmt + 1), DL, MVT::i8)), N->getOperand(0)); + } else if (IsPowerOf2_64MinusTwo && NumSign == 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(NumSign * SignMulAmt + 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)); } // To negate, subtract the number from zero - if ((IsPowerOf2_64PlusOne || IsPowerOf2_64MinusOne) && NumSign == -1) + if (NewMul && NumSign == -1) NewMul = DAG.getNode(ISD::SUB, DL, VT, DAG.getConstant(0, DL, VT), NewMul); } |
