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From: Janne Blomqvist <blomqvist.janne@gmail.com>
To: Thomas Koenig <tkoenig@netcologne.de>
Cc: "fortran@gcc.gnu.org" <fortran@gcc.gnu.org>,
	gcc-patches <gcc-patches@gcc.gnu.org>
Subject: Re: [patch, fortran] Implement maxloc and minloc for character
Date: Tue, 21 Nov 2017 16:25:00 -0000	[thread overview]
Message-ID: <CAO9iq9G_tGjJ=j229i2TTxeTZWZjc4aQYUVdL_GaSD83vLmKuA@mail.gmail.com> (raw)
In-Reply-To: <03e85917-b506-0d8b-78b0-263c371cba6a@netcologne.de>

On Mon, Nov 20, 2017 at 8:29 PM, Thomas Koenig <tkoenig@netcologne.de> wrote:
> Am 20.11.2017 um 09:30 schrieb Janne Blomqvist:
>>
>> On Sun, Nov 19, 2017 at 11:11 PM, Thomas Koenig <tkoenig@netcologne.de>
>> wrote:
>>>
>>> There is one question regarding the ABI. Apparently, the string length
>>> is passed as an int even on a 64-bit system. I verified that this
>>> is indeed the case by doing the actual work on a
>>> powerpc64-unknown-linux-gnu box (gcc110 on the gcc compile farm),
>>> which is big-endian. If we were actually passing an eight-byte
>>> quantity, and only getting the upper bytes, we would crash & burn.
>>>
>>> Now, I _thought_ we were passing string lengths as size_t now (Janne?),
>>> but maybe something was missing in that change.
>>
>>
>> Unfortunately I had to revert the charlen->size_t patch since it
>> caused regressions on aix/power (presumably due to endianness issues).
>
>
> Ah, that explains it. I had forgotten the reversion part.
>
>> There's apparently some other process for getting compile farm
>> accounts nowadays, and we have broken the ABI again for gcc 8, so
>> maybe I should dust off the patch and try again. Or what do you think?
>
>
> You can apply at https://cfarm.tetaneutral.net/ . These machines are
> indeed quite nice to work on, especially because of the different
> architectures (and because there are some very powerful machines
> there).
>
> So, any other comments about my patch? OK for trunk?

- In many cases the copyright notice has "This file is part of the GNU
Fortran 95 runtime library (libgfortran)." It's a while since we've
called ourselves "GNU Fortran 95", so just remove the "95".

- It seems in the library you're using int for string lengths? Please
use gfc_charlen_type instead (in the frontend, gfc_charlen_type_node).
(Most of the charlen->size_t patch is fixing up places where we're
accidentally using int instead of gfc_charlen_type..).

- Why are you using GFC_INTEGER_1 / GFC_INTEGER_4 to loop over the
arrays rather than char/gfc_char4_t? Not sure if it makes any
difference in practice, but it sure seems confusing..

- Not really related to your patch, but memcmp_char4 sure looks
redundant. Isn't it the same as memcmp(a, b, size*4), in which case we
could use optimized memcmp implementations?



-- 
Janne Blomqvist

  reply	other threads:[~2017-11-21 16:07 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-19 22:04 Thomas Koenig
2017-11-20  8:41 ` Janne Blomqvist
2017-11-20 18:33   ` Thomas Koenig
2017-11-21 16:25     ` Janne Blomqvist [this message]
2017-11-21 19:53       ` Thomas Koenig
2017-11-21 20:47         ` Janne Blomqvist
2017-11-22 18:16           ` Thomas Koenig
2017-11-23 13:25             ` Janne Blomqvist
2017-11-23 14:03               ` Janne Blomqvist
2017-11-23 14:06                 ` Ramana Radhakrishnan
2017-11-23 14:10                   ` Janne Blomqvist
2017-11-23 18:40               ` Thomas Koenig
2017-11-24  9:33                 ` Janne Blomqvist

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