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[Bug middle-end/31058] overflow warnings should not be enabled with -Wall
- From: "rakdver at atrey dot karlin dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 7 Mar 2007 22:17:09 -0000
- Subject: [Bug middle-end/31058] overflow warnings should not be enabled with -Wall
- References: <bug-31058-12049@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #19 from rakdver at atrey dot karlin dot mff dot cuni dot cz 2007-03-07 22:17 -------
Subject: Re: overflow warnings should not be enabled with -Wall
> IIRC there are some cases that are only caught in the 2nd vrp run. It is still
> a possibility if this bug cannot be fixed otherwise.
>
> However, I don't see the issue with this testcase.
>
> a) its not a flex array
well, it may be a flex array -- it is at the end of the structure.
> b) the unrolled loop produces out of bounds accesses
> c) hence, the unrolled version cannot ever be used
no, this cannot be derived.
> d) it shouldn't be produced in the first place.
Well, yes, this is true. It is quite unlikely that a programmer would
use length of 5 for a tail array, hence we should take this as a hint
and avoid prefetching the array.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31058