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Re: [Bug regression/40665] dereferencing type-punned pointer warnings cannot be disabled
- From: Andrew Pinski <pinskia at gmail dot com>
- To: "gcc-bugzilla at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- Cc: "gcc-bugs at gcc dot gnu dot org" <gcc-bugs at gcc dot gnu dot org>
- Date: Mon, 6 Jul 2009 20:50:14 -0700
- Subject: Re: [Bug regression/40665] dereferencing type-punned pointer warnings cannot be disabled
- References: <bug-40665-1600@http.gcc.gnu.org/bugzilla/> <20090707013408.913.qmail@sourceware.org>
Thus code is undefined you have an acess of a char array as a struct.
Yes you are only taking the address of an element but it is still
considered an acess by the standards.
Sent from my iPhone
On Jul 6, 2009, at 6:34 PM, "mikulas at artax dot karlin dot mff dot
cuni dot cz" <gcc-bugzilla@gcc.gnu.org> wrote:
------- Comment #2 from mikulas at artax dot karlin dot mff dot cuni
dot cz 2009-07-07 01:34 -------
Created an attachment (id=18146)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=18146&action=view)
a bug in -Wstrict-aliasing=3
This is an example of a flaw in -Wstrict-aliasing=3 (this mode is
very bad,
produces many false positives on my project and I'm wondering why is
it
default?)
Gcc man page says that -Wstrict-aliasing=3 produces less false
positives than
-Wstrict-aliasing=2. This is counterexample, it produces "type-
punned" warning
in -Wstrict-aliasing=3 mode and doesn't warn in -Wstrict-aliasing=2.
I added
(void *) casts everywhere, but they don't quash the warning.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40665