Date: Mon, 12 May 2014 10:30:55 -0400 From: "Anthony G. Basile" <basile@...nsource.dyc.edu> To: musl@...ts.openwall.com Subject: Re: Broken GCC versions: 4.8.2 and 4.9.0 On 05/12/14 05:28, Natanael Copa wrote: > On Sun, 11 May 2014 17:20:30 -0400 > Rich Felker <dalias@...c.org> wrote: > >> On Sun, May 11, 2014 at 04:08:37PM -0400, James Cloos wrote: >>>>>>>> "RF" == Rich Felker <dalias@...c.org> writes: >>> >>> RF> I've tested it on gcc.godbolt.org and others have tested with local >>> RF> gcc 4.8.2 and 4.9.0, probably distro-provided (I didn't ask). >>> >>> I just tried debian-sid's 4.9. That does show the bug. As does their >>> gcc-snapshot version (a 4.10 pre). >>> >>> Perhaps the distro(s) which have the bug with 4.8.2 backported the commit >>> where the bug first occurs? >> >> Sounds plausible. Maybe that will help find the offending commit. > > I have tried to reproduce the issue on Alpine Linux without success. We > have gcc-4.8.2 with lots of patches from gentoo and with a hardened > default (default enabled). All the gentoo+musl stages on the gentoo tree are built with 4.7.3 so I can't speak to this issue. > > I have tried run with GCC_SPECS=vanilla (should disable the hardened > part) and without the -Os without any difference. > > It would be interesting to know what patches was used on the affected > gcc-4.8.2 systems. What gcc gentoo patches are you using? Even vanilla gentoo has some. > >>> RF> I wonder if the broken GCC is using isl/cloog >>> >>> I use the graphite optimizer on my Gentoo box (which generated the >>> assembly I quoted). The graphite code is only used when one or more >>> of -floop-interchange -floop-strip-mine -floop-block are specified. >>> >>> Testing with those options doesn't change the results. >> >> OK, ruled that out then. > > We also have a patch that will dlopen libcloog-isl.so.4 instead of > link to it directly for upgrade purposes. I have tried to build musl > with and without libcloog-isl.so.4 installed without it making any > difference. > > >> >> Rich -- Anthony G. Basile, Ph. D. Chair of Information Technology D'Youville College Buffalo, NY 14201 (716) 829-8197
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