RE: [PATCH] Use strlen when searching for a nul char

[Joseph Myers <joseph at codesourcery dot com>]

On Wed, 7 Oct 2015, Wilco Dijkstra wrote:

> > I agree; I'd rather discourage the addition of such optimizations as
> > inlines in glibc unless they depend on information that's inherently not
> > available to GCC (e.g. properties of architecture-specific function
> > implementations in glibc).  As I said before in
> > <https://sourceware.org/ml/libc-alpha/2015-06/msg00146.html> the aim
> > should be to make the GNU system as a whole as good as possible.
> 
> Does this mean we no longer care about supporting older GCC versions
> efficiently in GLIBC?

We expect people caring about microoptimizations to use current tool 
versions.

> Ie. can we remove bits/string2.h and just do a trivial implementation of
> the inlines in string/string-inlines.c?

See the discussion starting at 
<https://sourceware.org/ml/libc-alpha/2015-05/msg00526.html>.  We could 
remove optimizations only relevant to old compilers (say pre-4.1 or 
pre-4.3, potentially pre-4.6 if that actually means significant cleanup), 
yes.

Note this does *not* automatically mean completely removing the header - 
for example, code mapping __func to __builtin_func may still be relevant, 
at least when building glibc, so you need to be careful that the code you 
remove really is dead with modern GCC.  And you need to allow for the x86 
version of string-inlines.c as well.  See my reviews of Ondřej's patches 
<https://sourceware.org/ml/libc-alpha/2015-05/msg00770.html> and 
<https://sourceware.org/ml/libc-alpha/2015-05/msg00772.html>.

-- 
Joseph S. Myers
joseph@codesourcery.com