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Fold shifts with undef operands.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28167 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-05-08 17:29:49 +00:00
parent 1b7371331f
commit 2cfd6746ae
1 changed files with 7 additions and 0 deletions
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7
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@ -1439,11 +1439,14 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
case ISD::FSUB:
case ISD::FDIV:
case ISD::FREM:
case ISD::SRA:
return N1; // fold op(undef, arg2) -> undef
case ISD::UDIV:
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
case ISD::SRL:
case ISD::SHL:
return getConstant(0, VT); // fold op(undef, arg2) -> 0
}
}
@ -1467,9 +1470,13 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
return N2; // fold op(arg1, undef) -> undef
case ISD::MUL:
case ISD::AND:
case ISD::SRL:
case ISD::SHL:
return getConstant(0, VT); // fold op(arg1, undef) -> 0
case ISD::OR:
return getConstant(MVT::getIntVTBitMask(VT), VT);
case ISD::SRA:
return N1;
}
}