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[Bug c/22485] pointer +- integer is never NULL
- From: "mattias at virtutech dot se" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 15 Jul 2005 09:12:56 -0000
- Subject: [Bug c/22485] pointer +- integer is never NULL
- References: <20050714131031.22485.mattias@virtutech.se>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From mattias at virtutech dot se 2005-07-15 09:12 -------
It could be made an option so the user can tell GCC whether to make
standard-conforming code go as fast as possible or if arithmetic on null
pointers (as a gcc extension, say) is needed. -fnull-pointer-arith?
(In reply to comment #13)
> Scanning a region of memory starting from zero, is not
> exactly the kind of thing never done in practice.
True, but that sort of code is already in danger, since GCC assumes that in
x = *p;
if (!p) shout();
the condition is never true (even if it is possible to read from location 0).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=22485