diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 26 |
1 files changed, 0 insertions, 26 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 737d9661fdf..acc00fd58b1 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2374,32 +2374,6 @@ SDOperand DAGCombiner::visitSRA(SDNode *N) { DAG.getValueType(EVT)); } - // fold sra (shl X, m), result_size - n - // -> (sign_extend (trunc (shl X, result_size - n - m))) for - // result_size - n != m. If truncate is free for the target sext(shl) is - // likely to result in better code. - if (N0.getOpcode() == ISD::SHL) { - // Get the two constanst of the shifts, CN0 = m, CN = n. - const ConstantSDNode *N01C = dyn_cast<ConstantSDNode>(N0.getOperand(1)); - if (N01C && N1C) { - // Determine if the truncate type's bitsize would correspond to - // an integer type for this target. - unsigned VTValSize = MVT::getSizeInBits(VT); - MVT::ValueType TruncVT = MVT::getIntegerType(VTValSize - N1C->getValue()); - unsigned ShiftAmt = N1C->getValue() - N01C->getValue(); - - // If the shift wouldn't be a noop, the truncated type is an actual type, - // and the truncate is free, then proceed with the transform. - if (ShiftAmt != 0 && - !MVT::isExtendedVT(TruncVT) && TLI.isTruncateFree(VT, TruncVT)) { - SDOperand Amt = DAG.getConstant(ShiftAmt, TLI.getShiftAmountTy()); - SDOperand Shift = DAG.getNode(ISD::SRL, VT, N0.getOperand(0), Amt); - SDOperand Trunc = DAG.getNode(ISD::TRUNCATE, TruncVT, Shift); - return DAG.getNode(ISD::SIGN_EXTEND, N->getValueType(0), Trunc); - } - } - } - // fold (sra (sra x, c1), c2) -> (sra x, c1+c2) if (N1C && N0.getOpcode() == ISD::SRA) { if (ConstantSDNode *C1 = dyn_cast<ConstantSDNode>(N0.getOperand(1))) { |
