On Tue, Jun 29, 2010 at 1:55 AM, Ian Lance Taylor <i...@google.com> wrote: > Artem Shinkarov <artyom.shinkar...@gmail.com> writes: > >> I'm trying to implement a support for vector shuffling. For this >> purpose I would like to introduce a built-in function and lower it >> down in the veclower pass. However the problem is, that I don't want >> to introduce a separate built-in function for each type. So the >> question is: how can I specify a built-in function that would accept >> any parameters, and would be expanded at some points to some proper >> types. There is a hacky solution like in this patch: >> http://gcc.gnu.org/ml/gcc-patches/2009-02/msg00096.html, but may be >> someone have an idea of a cleaner solution. > > Perhaps you could define the builtin function as a pure varargs > function, and do the appropriate type checking manually when folding the > call.
We already to that (varargs function) for the type-generic C99 fp classification functions (and use attribute "type generic" to mark them, especially to avoid applying default conversions for vararg calls). The type-generic C99 fp classification functions are a somewhat simple case though as they all have a fixed return type, int. For the case in question we need a return type that is determined by the function argument type(s). Thus there is both the complexity of teaching that to the FE and the middle-end. Richard. > Ian >
