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From: "samuel dot thibault at ens-lyon dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug target/36793] x86-64 does not get __sync_synchronize right Date: Fri, 21 Nov 2008 11:18:00 -0000 [thread overview] Message-ID: <20081121111644.3832.qmail@sourceware.org> (raw) In-Reply-To: <bug-36793-6365@http.gcc.gnu.org/bugzilla/> [-- Warning: decoded text below may be mangled, UTF-8 assumed --] [-- Attachment #1: Type: text/plain, Size: 1103 bytes --] ------- Comment #1 from samuel dot thibault at ens-lyon dot org 2008-11-21 11:16 ------- Just to confirm the bug: the gcc doc says it follows the Intel itanium binary interface. The Intel documentation says « Associated with each instrinsic are certain memory barrier properties that restrict the movement of memory references to visible data across the intrinsic operation (by either the compiler or the processor). » Not including the mfence instruction would let the processor move references across the instruction, so it is mandatory. And that is not only for x86_64, but also x86, on which you can use e.g. a locked nop if you don't know the arch, or a mfence when using -march= (IIRC it appeared with SSE2) -- samuel dot thibault at ens-lyon dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |samuel dot thibault at ens- | |lyon dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36793
next prev parent reply other threads:[~2008-11-21 11:18 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2008-07-10 15:10 [Bug target/36793] New: " jfc at mit dot edu 2008-11-21 11:18 ` samuel dot thibault at ens-lyon dot org [this message] 2008-11-21 17:24 ` [Bug target/36793] " ubizjak at gmail dot com 2008-11-21 17:37 ` hjl dot tools at gmail dot com 2008-11-21 17:38 ` hjl dot tools at gmail dot com 2008-11-21 23:22 ` samuel dot thibault at ens-lyon dot org 2008-11-21 23:40 ` hjl dot tools at gmail dot com 2008-11-22 18:30 ` ubizjak at gmail dot com 2008-11-22 19:42 ` samuel dot thibault at ens-lyon dot org 2008-11-24 16:58 ` uros at gcc dot gnu dot org 2008-11-24 17:00 ` ubizjak at gmail dot com 2008-11-25 9:16 ` ubizjak at gmail dot com
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