[PATCH, AArch64] Add optimized strchrnul

[Kyle McMartin]

On Tue, Dec 09, 2014 at 02:38:11PM -0800, Andrew Pinski wrote:
> > Hrm, I've bisected this commit as the cause of localedef segfaulting as
> > part of install-locales... it ends up crashing weirdly inside of
> > vsprintf's internals. Have either of you seen anything similar?
> 
> I just ran into this with an ILP32 compiled glibc (with thunderX
> tuning and some extra patches) where printf was crashing.  The problem
> is v15 is being used but it is a callee saved register.  Here is the
> documentation from the ABI:
> Registers v8-v15 must be preserved by a callee across subroutine
> calls; the remaining registers (v0-v7, v16-v31)
> do not need to be preserved (or should be preserved by the caller).
> 

Aha, I'd debugged to the same point today after comparing logs between
the C and assembler versions of strchrnul. I swapped vrepmask for v7 and
things chugged along as expected.

--Kyle

> Thanks,
> Andrew Pinski
>