* Kevin Kofler: > Dave Love wrote: >> they'd be rather limited by the compiler options we're supposed to use, >> that don't include vectorization, so you don't even get the benefit you >> could from SSE2. (I've been told off in review for turning that on, >> though an FPC member has approved it.) > > Why don't we enable -ftree-vectorize by default? GCC upstream thinks that it is still not beneficial in general. Obviously, there will always be *some* regressions, but for GCC 9, the thinking was that the regressions still outweight the striking benefits in some cases. I believe Clang enables the auto-vectorizer at -O2. >> However, hwcaps won't help for programs with no separate library >> performance component; Gromacs is an example. On a heterogeneous HPC >> system you need multiple parallel-installable versions with a convention >> for the paths they'll be on. > > As I wrote elsewhere in this huge thread: just turn the program into a > library with a dummy main program. That requires manual work, so it's unclear how to do this for large parts of the distribution. And people will worry about PIC-related losses, or due to assumptions regarding symbol interposition (which affect inter-procedural analysis). The latter even affects Fedora because PIE does not turn off these optimizations. Thanks, Florian _______________________________________________ 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
