On Mon, Feb 11, 2019 at 01:47:16PM +0100, Ingo Molnar wrote:
> * Alexey Dobriyan <adobri...@gmail.com> wrote:

> > QUESTION: is it possible to tell gcc "this function is semantically
> > equivalent to memset(3) so make high level optimizations but call it
> > when it is necessary"? I suspect the answer is "no" :-\
> 
> No idea ...
> 
> > TODO:
> >     CONFIG_FORTIFY_SOURCE is enabled by distros
> >     benchmarks
> >     testing
> >     more comments
> >     check with memset_io() so that no surprises pop up
> 
> I'd only like to make happy noises here to make sure you continue with 
> this work - it does look promising. :-)

Thanks, Ingo.

This is really the core of the problem: once memset() becomes something
other than

        static inline void *memset(void *p, int c, size_t len)
        {
                return __builtin_memset(p, c, len);
        }

GCC starts pretending that it doesn't know what memset() is and all those
advertised space savings go to hell.

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