Hi! gcc 12 snapshot has landed as the system compiler into rawhide today. GCC 12 is going to enter its stage4 development phase (only regression and documentation bugfixes allowed) on Monday 17th, so there should be just those bugfixes and not new features etc. anymore. https://gcc.gnu.org/gcc-12/changes.html lists important changes, most important is probably that vectorization is enabled at -O2 now which is the option with most of the distribution is built with. https://gcc.gnu.org/gcc-12/porting_to.html is so far incomplete and lists some cases where people need to adjust their code. Other things include the usual C++ header changes, where previously some standard header included some other header as an implementation detail but it doesn't any longer and so code that relied on such indirect include that isn't required by the standard needs to include the header that provides whatever it relies on. Or e.g. packages using -Werror where new warnings are reported with the newer compiler and -Werror results in build failures. If there are bugs on the compiler side, please let me know immediately, so that those bugs can be fixed before the mass rebuild next week. Another important thing I wanted to say is that we'd like to switch ppc64le from the numerically problematic IBM extended long double to IEEE 754 quad long double. This is an ABI change. Some libraries are already built so that they support both ABIs at the same time, including glibc, libstdc++, libgcc, libgfortran etc. For other libraries and binaries, the compiler, assembler and linker will notice if they use long double and flag them as using either IBM or IEEE long double and linker (or I think dynamic linker too) might complain when things are mixed. Right now the rawhide gcc still defaults to -mabi=ibmlongdouble but the glibc/gcc libraries are built compatibly with both. We'd like to configure gcc shortly before the mass rebuild with --with-long-double-format=ieee so that it will default to -mabi=ieeelongdouble, probably on a side-tag build first, and it will be highly desirable to rebuild at least some of the most commonly used library packages in the order of dependencies there, otherwise I'd be afraid the mass rebuild could fail for way too many packages (as the mass rebuild doesn't do dependency order rebuilds but just goes through packages alphabetically or so). Any suggestions on which packages have commonly used library packages that use long double? readelf -A on libraries on ppc64le prints either nothing (either the library is thought not to use long double or supports both ABIs transparently or hasn't been rebuilt for some years), or Attribute Section: gnu File Attributes Tag_GNU_Power_ABI_FP: hard float, 128-bit IBM long double for libraries (or binaries or object files) that use IBM long double only or Attribute Section: gnu File Attributes Tag_GNU_Power_ABI_FP: hard float, 128-bit IEEE long double for IEEE long doubles. So I think we want to rebuild on a side-tag packages that provide shared libraries used by hundreds of other packages that are Tag_GNU_Power_ABI_FP: hard float, 128-bit IBM long double right now. Jakub _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
