Dominique Martinet wrote on Tue, Aug 04, 2020: > So I'd really need a way to have only that file compiled with the > optimisations, and other files without it -- Jeff or someone else, could > you please advise? I could still use help with that, please. To recap, waypipe: - compiles a single function in single .c file into a static lib (.a) with optimisations e.g. `-mavx512f -mlzcnt -mbmi` or `-mfpu=neon` depending on what the compiler provides. - compiles other stuff without these optimisations; the other stuff knows what has been compiled or not through #ifdefs. - link the other stuff with that aforementioned .a ( - at runtime, decides if it is safe or not to run the optimized function, and only runs it if the hardware supports it -- since the code that makes the decision is compiled without the optimizations the binary as a whole should run on whatever we support) with -flto=auto, the final link step fails with the following: https://kojipkgs.fedoraproject.org//work/tasks/2576/48362576/build.log ------ gcc -o test/diff_roundtrip test/diff_roundtrip.p/diff_roundtrip.c.o -Wl,--as-needed -Wl,--no-undefined -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -march=armv7-a -mfpu=vfpv3-d16 -mtune=generic-armv7-a -mabi=aapcs-linux -mfloat-abi=hard -Wl,-z,relro -Wl,--as-needed -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld -Wl,--start-group src/libwaypipe_src.a src/libkernel_neon.a protocols/libprotocols.a -pthread -lrt /usr/lib/libgbm.so /usr/lib/liblz4.so /usr/lib/libzstd.so -Wl,--end-group '-Wl,-rpath,$ORIGIN/../src:$ORIGIN/../protocols' -Wl,-rpath-link,/builddir/build/BUILD/waypipe-v0.6.1/armv7hl-redhat-linux-gnueabi/src -Wl,-rpath-link,/builddir/build/BUILD/waypipe-v0.6.1/armv7hl-redhat-linux-gnueabi/protocols /usr/lib/gcc/armv7hl-redhat-linux-gnueabi/10/include/arm_neon.h: In function ‘run_interval_diff_neon’: /usr/lib/gcc/armv7hl-redhat-linux-gnueabi/10/include/arm_neon.h:10426:22: fatal error: You must enable NEON instructions (e.g. ‘-mfloat-abi=softfp’ ‘-mfpu=neon’) to use these intrinsics. 10426 | return (uint64x2_t)__builtin_neon_vld1v2di ((const __builtin_neon_di *) __a); | ^ compilation terminated. ------ where `run_interval_diff_neon`is the optimised function that was compiled in the first .a with optimization flags >From what I have read it's not possible to mark a function or a file as "LTO disabled"? Did I get that correctly? What can I or upstream do about this? I mean, I can disable LTO in the spec file but what _should_ I do ;) Is it a bug I should file a gcc bz for or is that a feature I don't understand? FWIW I don't have the problem with avx512f, it links just fine. Thanks, -- Dominique _______________________________________________ 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
