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Re: RFC: Update ISL under gcc/infrastructure/ ? // Remove CLooG?
- From: Tobias Grosser <tobias at grosser dot es>
- To: Tobias Burnus <tobias dot burnus at physik dot fu-berlin dot de>, gcc at gcc dot gnu dot org
- Cc: Richard Biener <richard dot guenther at gmail dot com>, Roman Gareev <gareevroman at gmail dot com>, Albert Cohen <albert dot cohen at inria dot fr>, Sven Verdoolaege <skimo at kotnet dot org>, Mircea Namolaru <mircea dot namolaru at inria dot fr>
- Date: Thu, 06 Nov 2014 00:39:42 +0100
- Subject: Re: RFC: Update ISL under gcc/infrastructure/ ? // Remove CLooG?
- Authentication-results: sourceware.org; auth=none
- References: <20141104151755 dot GA13200 at physik dot fu-berlin dot de>
On 04.11.2014 16:17, Tobias Burnus wrote:
Hi all,
currently, contrib/download_prerequisites downloads isl-0.12.2 from
ftp://gcc.gnu.org/pub/gcc/infrastructure/$ISL.tar.bz2
However, that version has a bug which causes an ICE (PR 62289).
End of October, ISL 0.14 was released, which should contain a fix for
that issue. Hence, one should consider using 0.14 instead of /infrastructure/
and download_prerequisites.
Download: http://isl.gforge.inria.fr
Thanks Tobias for bringing this one up.
Disclaimer: I haven't tested that version, yet.
* * *
The page https://gcc.gnu.org/install/prerequisites.html lists 0.12.2 as
version to be used (without "(or later)").
The configure script does some version checks, but seeminly only to rule
out early version of ISL as it is only the check for an include file.
According to https://groups.google.com/forum/#!topic/isl-development/CQGVfj60SQM
"0.14 was kept backward compatible with 0.13." [But 0.15 will break it.]
Thus, assuming 0.13 works, 0.14 also should work. Release notes:
http://repo.or.cz/w/isl.git/blob/HEAD:/ChangeLog
Right. 0.13 should work from svn revision 213816.
As Richard pointed out, isl introduce a backward incompatible change in
0.13 that unfortunately made it impossible to compile 4.8 with isl 0.13.
Judging from Richards comments, this seems to continue to cause issues.
@Sven, we need to be very careful with such changes in the future. If it
is low cost, we may even consider to make isl_int again available for
a couple of releases (from 0.14.1 on).
Comments? Especially from Richard and Tobias?
* * *
Finally, is CLooG still needed or will GCC also work with only ISL? Looking
at https://gcc.gnu.org/ml/gcc-patches/2014-08/msg01742.html , it seems as if
it is about the right time to remove it.
CLooG is not necessarily needed. You can run graphite just with ISL. The
main reason that ISL code generation is not enabled by default is that
we did not yet get extensive testing and it was unclear who will have
the time to fix possible bugs.
@Mircae, Roman: Would you have time to help with bug-fixing if we do the
switch now? (I am happy to review patches and give advice, but can not
do the full move myself)
Cheers,
Tobias