// <summary>
// This routine will attempt to simplify the unary expression when the
// argument is a constant. The result is returned in `result' and the
// function returns true or false depending on whether a reduction
// was performed or not
// </summary>
bool Reduce (EmitContext ec, Constant e, out Expression result)
{
Type expr_type = e.Type;
switch (Oper){
case Operator.UnaryPlus:
result = e;
return true;
case Operator.UnaryNegation:
result = TryReduceNegative (e);
return true;
case Operator.LogicalNot:
if (expr_type != TypeManager.bool_type) {
result = null;
Error23 (expr_type);
return false;
}
BoolConstant b = (BoolConstant) e;
result = new BoolConstant (!(b.Value));
return true;
case Operator.OnesComplement:
if (!((expr_type == TypeManager.int32_type) ||
(expr_type == TypeManager.uint32_type) ||
(expr_type == TypeManager.int64_type) ||
(expr_type == TypeManager.uint64_type) ||
(expr_type.IsSubclassOf (TypeManager.enum_type)))){
result = null;
if (ImplicitConversionExists (ec, e, TypeManager.int32_type)){
result = new Cast (new TypeExpr (TypeManager.int32_type, loc), e, loc);
result = result.Resolve (ec);
} else if (ImplicitConversionExists (ec, e, TypeManager.uint32_type)){
result = new Cast (new TypeExpr (TypeManager.uint32_type, loc), e, loc);
result = result.Resolve (ec);
} else if (ImplicitConversionExists (ec, e, TypeManager.int64_type)){
result = new Cast (new TypeExpr (TypeManager.int64_type, loc), e, loc);
result = result.Resolve (ec);
} else if (ImplicitConversionExists (ec, e, TypeManager.uint64_type)){
result = new Cast (new TypeExpr (TypeManager.uint64_type, loc), e, loc);
result = result.Resolve (ec);
}
if (result == null || !(result is Constant)){
result = null;
Error23 (expr_type);
return false;
}
expr_type = result.Type;
e = (Constant) result;
}
if (e is EnumConstant){
EnumConstant enum_constant = (EnumConstant) e;
Expression reduced;
if (Reduce (ec, enum_constant.Child, out reduced)){
result = new EnumConstant ((Constant) reduced, enum_constant.Type);
return true;
} else {
result = null;
return false;
}
}
if (expr_type == TypeManager.int32_type){
result = new IntConstant (~ ((IntConstant) e).Value);
} else if (expr_type == TypeManager.uint32_type){
result = new UIntConstant (~ ((UIntConstant) e).Value);
} else if (expr_type == TypeManager.int64_type){
result = new LongConstant (~ ((LongConstant) e).Value);
} else if (expr_type == TypeManager.uint64_type){
result = new ULongConstant (~ ((ULongConstant) e).Value);
} else {
result = null;
Error23 (expr_type);
return false;
}
return true;
case Operator.AddressOf:
result = this;
return false;
case Operator.Indirection:
result = this;
return false;
}
throw new Exception ("Can not constant fold: " + Oper.ToString());
}
