Re: help on adding new insns like min/max

[Dale Johannesen <dalej at apple dot com>]

On Monday, October 21, 2002, at 04:05  PM, Ming Ouyang wrote:

> I tried my gcc with definition of sminsi3/smaxsi3 and I dumpped
> all debug info, gcc always treats min as a function call in my
> test.c.00.rtl through test.c.30.dbr:
>
> (call (mem:SI (symbol_ref/v:SI ("smin")) ))
>
> I think once gcc found that is a function call, it would not
> optimize it, am I right?
> What I should get is something like "(smin: SI ...", is that right?
> So probably I need to change something other than xxx.md?
> Thanks.
If you're using it as a function of course gcc will treat it as
a function.  It is not one of the standard C functions so gcc does
not do anything special to it (and is not allowed to, that would
break standard conformance).  The usual way to get min/max functionality
in C is to put a macro definition in a header file somewhere, something 
like
#define MAX(x,y) ((x>y) ? x : y)
(watch out for ++ operators, improvement left as an exercise)