On Wed, Sep 14, 2016 at 03:41:33PM +0200, Richard Biener wrote:
> > We've seen several different proposals for where/how to do this
> > simplification, why did you
> > say strlenopt is best? It would be an unconditional strchr (a, 0) -> a +
> > strlen (a) rewrite,
> > ie. completely unrelated to what strlenopt does. We do all the other
> > simplifications based
> > on constant arguments in builtins.c and gimple-fold.c, why is strchr (s, 0)
> > different?
>
> I was thinking about the case where strlen opt already knows strlen
> (a). But sure, gimple-fold.c
> works as well.
I think for the middle-end, using strchr (a, 0) as canonical instead of a +
strlen (a)
is better, and at expansion time we can decide what to use (a + strlen (a)
if you'd expand strlen inline, rather than as a function call, or
__rawmemchr (which if libc is sane should be fastest), or strchr, or a + strlen
(a)).
Jakub
