public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "alexey.lapshin at oracle dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/65146] New: alignment of _Atomic structure member is not correct Date: Fri, 20 Feb 2015 19:58:00 -0000 [thread overview] Message-ID: <bug-65146-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65146 Bug ID: 65146 Summary: alignment of _Atomic structure member is not correct Product: gcc Version: 4.9.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: alexey.lapshin at oracle dot com Alignment of single _Atomic object match with documentation : https://gcc.gnu.org/wiki/Atomic/GCCMM/UnalignedPolicy . Alignment of _Atomic structure member does not match. ~/atomic_test$ cat unaligned_atomic.c #include <stdatomic.h> #include <stdio.h> typedef struct { char c [8]; } power_of_two_obj; typedef struct { char c[1]; _Atomic power_of_two_obj ao; } container_struct; int main ( void ) { _Atomic power_of_two_obj obj1; container_struct obj2; printf("\n Size and Alignment of _Atomic object "); printf(" : sizeof(obj1) %d __alignof__(obj1) %d ", sizeof(obj1), __alignof__(obj1) ); printf("\n Size and Alignment of _Atomic member object "); printf(" : sizeof(obj2.ao) %d __alignof__(obj2.ao) %d \n", sizeof(obj2.ao), __alignof__(obj2.ao) ); return 0; } ~/atomic_test$ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/opt/gcc/libexec/gcc/i386-pc-solaris2.11/4.9.2/lto-wrapper Target: i386-pc-solaris2.11 Configured with: ./configure --prefix=/opt/gcc/ Thread model: posix gcc version 4.9.2 (GCC) ~/atomic_test$ gcc -O -latomic -std=c11 unaligned_atomic.c -m32 ~/atomic_test$ ./a.out Size and Alignment of _Atomic object : sizeof(obj1) 8 __alignof__(obj1) 8 Size and Alignment of _Atomic member object : sizeof(obj2.ao) 8 __alignof__(obj2.ao) 4 According to the documentation https://gcc.gnu.org/wiki/Atomic/GCCMM/UnalignedPolicy alignment of both "obj1" and "obj2.ao" should be 8 bytes. But in the above test case alignment of obj2.ao is 4 bytes. The bug is found on Solaris x86 -m32
next reply other threads:[~2015-02-20 19:29 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-02-20 19:58 alexey.lapshin at oracle dot com [this message] 2015-02-20 21:43 ` [Bug c/65146] " joseph at codesourcery dot com 2015-02-20 22:51 ` alexey.lapshin at oracle dot com 2015-02-20 23:32 ` joseph at codesourcery dot com 2020-08-26 14:59 ` [Bug target/65146] " jason at gcc dot gnu.org 2020-08-26 16:03 ` jakub at gcc dot gnu.org 2020-08-26 17:33 ` jakub at gcc dot gnu.org 2020-08-26 17:58 ` hjl.tools at gmail dot com 2020-08-27 16:45 ` cvs-commit at gcc dot gnu.org 2022-04-27 12:37 ` peter at cordes dot ca 2023-12-04 10:10 ` egallager at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-65146-4@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).