RE: Builtins and C++ and such

[Bernard Dautrevaux <Dautrevaux at microprocess dot com>]

> -----Original Message-----
> From: Jason Merrill [mailto:jason@redhat.com]
> Sent: Wednesday, March 20, 2002 11:20 AM
> To: Gabriel Dos Reis
> Cc: Mark Mitchell; gcc@gcc.gnu.org; bkoz@redhat.com
> Subject: Re: Builtins and C++ and such
> 
> 
> >>>>> "Gabriel" == Gabriel Dos Reis <gdr@codesourcery.com> writes:
> 
> > I'm strongly of the opinion of Jason that, even though the ideal
> > would be to have the library do most of the dirty work, the compiler
> > ought to assist us through some extensions.
> 
> Actually, I disagree about the ideal.  I think the compiler 
> is The Right
> Place for this stuff.
> 
> > Here is a fourth suggestion.
> > Suppose for a moment that the compiler is smart enought (or can be
> > made smart) to replace a reference to a function by the
> > referenced function where possible, then we could say:
> 
> >    void(&memcpy)(void*, const void*, size_t) = __builtin_memcpy;
> 
> Again, this would involve putting the library through 
> contortions in order
> to tell the compiler about itself.


And IMHO gcc nowhere has a list of all builtins, with a guarantee this will
*never* change on *any* target, so the library will have to go in infinite
contorsions to keep with the compilers and various targets... 

FWIW I think the compiler is the one that *creates* the problem with
builtins, used as an internal optimization. It is then the one that have
cope with their proper semantics/usefulness.
 
        Bernard

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Bernard Dautrevaux
Microprocess Ingenierie
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