On Fri, 22 Nov 2013, Jakub Jelinek wrote: > How do i?86 _Atomic long long and _Atomic long double work btw? > At least when they are inside of structures, they have 4 byte alignment.
If the generic libatomic functions are called, they use locking if alignment is inadequate (libatomic presumes natural alignment is the required alignment for size-specific operations). If the operations are inlined or the size-specific libatomic functions are called, you may indeed have problems. Plausible fixes for such issues include: * Probably x86_field_alignment should not reduce alignment for fields of atomic type. * The code in c-common.c resolving size-generic atomic builtins to size-specific ones should not do so if the alignment is less than natural (taking account of possible alignment reductions for fields, so working out pointer target alignment conservatively). (And of course add testcases for any bugs this fixes.) -- Joseph S. Myers jos...@codesourcery.com
