|Summary:||Changes/LTO by default for package builds|
|Product:||[Fedora] Fedora||Reporter:||Ben Cotton <bcotton>|
|Component:||Changes Tracking||Assignee:||Jeff Law <law>|
|Status:||CLOSED CURRENTRELEASE||QA Contact:|
|Version:||33||CC:||bcotton, besser82, ego.cordatus, fabio.pedretti, kdudka, law, rjones|
|Fixed In Version:||Doc Type:||If docs needed, set a value|
|Doc Text:||Story Points:||---|
|Last Closed:||2020-10-27 14:48:00 UTC||Type:||---|
|oVirt Team:||---||RHEL 7.3 requirements from Atomic Host:|
|Cloudforms Team:||---||Target Upstream Version:|
|Bug Depends On:||1861276, 1872429, 1873188, 1877652|
Description Ben Cotton 2020-01-08 19:21:42 UTC
This is a tracking bug for Change: Changes/LTO by default for package builds For more details, see: https://fedoraproject.org/wiki/LTOByDefault This is a proposal to enable link time optimization (LTO) of packages built with rpmbuild by default. It's an over-simplification, but think of LTO as deferring analysis, optimization and code generation until creation of an executable or dynamic shared object.
Comment 1 Kamil Dudka 2020-07-24 15:23:31 UTC
This change causes failure of gnulib's test-float test on ppc64le, which prevents packages that use gnulib's float module from being built: https://koji.fedoraproject.org/koji/taskinfo?taskID=47694984 Minimal example: $ git clone --depth 1 https://git.savannah.gnu.org/git/gnulib.git $ cd gnulib $ git checkout 7ea899a94365ece6367515a7e61452d9d2e61730 $ ./gnulib-tool --create-testdir --dir=tst float $ cd tst $ ./configure CFLAGS='-flto -O2 -m64 -mcpu=power8 -mtune=power8' $ make check $ cat gltests/test-suite.log =============================== dummy 0: ./test-suite.log =============================== # TOTAL: 1 # PASS: 0 # SKIP: 0 # XFAIL: 0 # FAIL: 1 # XPASS: 0 # ERROR: 0 .. contents:: :depth: 2 FAIL: test-float ================ test-float.c:318: assertion 'm + m > m' failed FAIL test-float (exit status: 134) After removing -flto from CFLAGS, the test passes just fine.
Comment 2 Jeff Law 2020-07-27 05:15:06 UTC
This is almost certainly a broken configure test which in turn causes the mis-behavior of the gnulib float test. I'll have to verify tomorrow, but the autoconf tests which determine how gnulib packs/unpacks floating point numbers is one that's known to be broken WRT ISO C aliasing rules.
Comment 3 Kamil Dudka 2020-07-27 09:22:48 UTC
Jeff, thank you for looking into this! We had a similar problem with gnulib's test-isinf test on ppc64le four years ago but gnulib upstream is not much receptive to such reports without patches: https://lists.gnu.org/archive/html/bug-gnulib/2016-01/msg00011.html For now I have disabled LTO on ppc64le in coreutils and findutils to make the packages build again: https://src.fedoraproject.org/rpms/coreutils/c/6d3ccf4f https://src.fedoraproject.org/rpms/findutils/c/8de28b81
Comment 4 Jeff Law 2020-08-10 21:16:17 UTC
Moving to MODIFIED as this feature is in the testable state.
Comment 5 Ben Cotton 2020-08-11 13:10:49 UTC
Branching F33 Change Tracker bugs. Today is the code complete (testable) deadline. All bugs should be at least in MODIFIED state by now to indicate they are testable.
Comment 6 Ben Cotton 2020-08-27 01:12:01 UTC
Yesterday we reached the Code complete (100% code complete) deadline for Fedora 33 Changes. If your Change is complete, please set this tracking bug to ON_QA. If you need to defer this Change to Fedora 34, please let NEEDINFO me. As a reminder, we are now in the Beta Freeze. If you need to land package updates, please propose it as a Freeze Exception at https://qa.fedoraproject.org/blockerbugs/propose_bug
Comment 7 Ben Cotton 2020-10-27 14:48:00 UTC
Closing tracking bugs for F33. If your change didn't make it into F33 for some reason, please reopen this and NEEDINFO me.