Re: help on adding new insns like min/max

[Ming Ouyang <mouyang at yahoo dot com>]

I also found that just now :) Anyway, thank you very very much.

Ming

--- Andrew Pinski <apinski@apple.com> wrote:
> Actually I messed up the definition of max:
> 
> #define max(a,b) ({__typeof__(a) a1=(a); __typeof__(b) b1 = (b); 
> (a1>b1)?a1:b1})
> 
> Sorry,
> Andrew Pinski
> 
> 
> On Monday, Oct 21, 2002, at 18:03 US/Pacific, Ming Ouyang wrote:
> 
> > Andrew,
> > Thanks for your reply. __typeof__ does make 2 or more min/max in one
> > function work, but it can't resolve complicated operands problem yet,
> > can you help on that?
> > Thanks so much.
> >
> > Ming
> >
> >
> > --- Andrew Pinski <apinski@apple.com> wrote:
> >> try this, using extensions for gcc:
> >>
> >> #define max(a,b) ({__typeof__(a) a1=(a); __typeof__(b) b1 = (b);
> >> (a>b)?a:b})
> >>
> >> Thanks,
> >> Andrew Pinski
> >>
> >> On Monday, Oct 21, 2002, at 17:34 US/Pacific, Ming Ouyang wrote:
> >>
> >>> Dale,
> >>> I just found that macro doesn't always work well, for any complicated
> >>> operands like: max(a, ++b), max(a+b, c), max(a, foo(c)), gcc won't
> >>> use max insn for them, it only use max insn for max(a,b).
> >>> In addition, if I have more than one maxs/mins, it seems gcc will
> >>> not generate max/min for them, could you give me some help on that?
> >>> Thanks a lot.
> >>>
> >>> Ming
> >>>
> >>> --- Dale Johannesen <dalej@apple.com> wrote:
> >>>>
> >>>> 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)
> >>>>
> >>>
> >>>
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