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Re: [PATCH, AArch64] Add optimized strchrnul

On 09/12/14 22:38, Andrew Pinski wrote:
> On Wed, Dec 3, 2014 at 9:45 AM, Kyle McMartin <> wrote:
>> On Wed, Nov 05, 2014 at 02:02:22PM +0000, Marcus Shawcroft wrote:
>>> On 13 June 2014 11:23, Richard Earnshaw <> wrote:
>>>> Here is an optimized implementation of __strchrnul.  The simplification
>>>> that we don't have to track precisely why the loop terminates (match or
>>>> end-of-string) means we have to do less work in both setup and the core
>>>> inner loop.  That means this should never be slower than strchr.
>>>> As with strchr, the use of LD1 means we do not need different versions
>>>> for big-/little-endian.
>>>> <date>  Richard Earnshaw  <>
>>>>         * sysdeps/aarch64/strchrnul.S: New file.
>>> Committed. + NEWS entry. /Marcus
>> 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).
> Thanks,
> Andrew Pinski
>> regards, Kyle

Well spotted!  I'll push a fix round the various implementations of this


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