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Subject: [Bug middle-end/46488] [4.5 regression] server/core_filters.c from apache httpd 2.2.17 miscompiled at -O3
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46488

--- Comment #32 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-11-30 15:10:58 UTC ---
The problem appears to be deeply rooted in the Ring construct, more precisely
in the HEAD trick.  IIUC the idea is to "attach" a doubly-linked list to
another structure by means of a "virtual" member overlaid on top of the
structure; the only thing they actually share is a special APR_RING_ENTRY (the
APR_RING_HEAD).  But this overlay fundamentally violates the aliasing rules
even if one try to narrow the accesses to just the shared part.

Richard, is that how the aliasing rules are implemented in the 4.5.x series? 
Has this been changed in 4.6.0?