Date: Tue, 18 Sep 2012 20:17:06 +0000 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Jeff Roberson <jroberson@jroberson.net> Cc: Konstantin Belousov <kostikbel@gmail.com>, attilio@freebsd.org, freebsd-arch@freebsd.org, arch@freebsd.org Subject: Re: Aliasing issue with TAILQ on ppc64 ? Message-ID: <23196.1347999426@critter.freebsd.dk> In-Reply-To: Your message of "Tue, 18 Sep 2012 09:00:38 -1000." <alpine.BSF.2.00.1209180858190.47770@desktop>
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In message <alpine.BSF.2.00.1209180858190.47770@desktop>, Jeff Roberson writes:
>If you compile at low optimization levels I assume it goes away?
I don't have access to the machine at this time, and in general
I'm not particular focused on PPC64, since this is a general
problem on any architecture, as I understand the C-language rules.
>Can you place asm volatile ("" ::: "memory"); between the two tailq macros
>with the same optimization level?
I tried earlier to put a printf("FOO") there, and that fixed it, which
I why I diagnosed it as an aliasing issue in the first place.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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