On Wed, Feb 05, 2020 at 05:13:27PM +0000, Dave Love wrote: > GCC doesn't document the targets for which -fno-common produces better > code. Can someone say for which of the Fedora ones it makes a > difference? E.g. on any that is capable of vectorization. Common vars can't have alignment increased, while normal .bss vars can, because the common vars could be actually defined in some other TU e.g. with a non-common var and the alignment of that definition would be what is then used. Similarly, on -fsection-anchors targets (e.g. aarch64, powerpc*, s390*) .bss vars can be accessed using section anchors, while .common vars can't. Or e.g. -fsanitize=address can't add red zone around .common vars and so doesn't detect buffer overflows in them. 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
