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[Bug c/16721] [3.5 Regression] Accesses to volatile objects optimized away
- From: "macro at linux-mips dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 27 Jul 2004 12:25:35 -0000
- Subject: [Bug c/16721] [3.5 Regression] Accesses to volatile objects optimized away
- References: <20040726181156.16721.macro@linux-mips.org>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From macro at linux-mips dot org 2004-07-27 12:25 -------
(In reply to comment #2)
> I can reproduce this on alphaev68-linux.
>
> In the test case you gave, removing the access seems entirely appropriate
> to me, since addr is not volatile.
>
> However, the same happens if you mark it volatile, so this is really a bug.
> -fno-strict-aliasing is a red herring; the access also gets optimized away for
>
> struct data { volatile unsigned long addr; } p;
> void test() { p.addr; }
>
> at -O2.
>
p->addr is not volatile, but *p->addr is. Threfore the original test case is valid.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16721