diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 0956cb519ef..614525b1f52 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2555,6 +2555,20 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { if (N1.isUndef()) return N1; + // fold Y = sra (X, size(X)-1); sub (xor (X, Y), Y) -> (abs X) + if (TLI.isOperationLegalOrCustom(ISD::ABS, VT)) { + if (N0.getOpcode() == ISD::XOR && N1.getOpcode() == ISD::SRA) { + SDValue X0 = N0.getOperand(0), X1 = N0.getOperand(1); + SDValue S0 = N1.getOperand(0); + if ((X0 == S0 && X1 == N1) || (X0 == N1 && X1 == S0)) { + unsigned OpSizeInBits = VT.getScalarSizeInBits(); + if (ConstantSDNode *C = isConstOrConstSplat(N1.getOperand(1))) + if (C->getAPIntValue() == (OpSizeInBits - 1)) + return DAG.getNode(ISD::ABS, SDLoc(N), VT, S0); + } + } + } + // If the relocation model supports it, consider symbol offsets. if (GlobalAddressSDNode *GA = dyn_cast<GlobalAddressSDNode>(N0)) if (!LegalOperations && TLI.isOffsetFoldingLegal(GA)) { @@ -5660,13 +5674,19 @@ SDValue DAGCombiner::visitXOR(SDNode *N) { } // fold Y = sra (X, size(X)-1); xor (add (X, Y), Y) -> (abs X) - unsigned OpSizeInBits = VT.getScalarSizeInBits(); - if (N0.getOpcode() == ISD::ADD && N0.getOperand(1) == N1 && - N1.getOpcode() == ISD::SRA && N1.getOperand(0) == N0.getOperand(0) && - TLI.isOperationLegalOrCustom(ISD::ABS, VT)) { - if (ConstantSDNode *C = isConstOrConstSplat(N1.getOperand(1))) - if (C->getAPIntValue() == (OpSizeInBits - 1)) - return DAG.getNode(ISD::ABS, SDLoc(N), VT, N0.getOperand(0)); + if (TLI.isOperationLegalOrCustom(ISD::ABS, VT)) { + SDValue A = N0.getOpcode() == ISD::ADD ? N0 : N1; + SDValue S = N0.getOpcode() == ISD::SRA ? N0 : N1; + if (A.getOpcode() == ISD::ADD && S.getOpcode() == ISD::SRA) { + SDValue A0 = A.getOperand(0), A1 = A.getOperand(1); + SDValue S0 = S.getOperand(0); + if ((A0 == S && A1 == S0) || (A1 == S && A0 == S0)) { + unsigned OpSizeInBits = VT.getScalarSizeInBits(); + if (ConstantSDNode *C = isConstOrConstSplat(S.getOperand(1))) + if (C->getAPIntValue() == (OpSizeInBits - 1)) + return DAG.getNode(ISD::ABS, SDLoc(N), VT, S0); + } + } } // fold (xor x, x) -> 0 |
