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From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/58009] Elements with same value in vector subscript in variable definition context
Date: Sun, 28 Jul 2013 11:25:00 -0000	[thread overview]
Message-ID: <bug-58009-4-EPGUtiMR76@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-58009-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58009

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |burnus at gcc dot gnu.org

--- Comment #4 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to Thomas Koenig from comment #3)
> a([i,j,i]) = ...
> for which I cannot think of an algorithm which is O(n),
> so I guess it will have to be O(n**2).

Given that most code has either no or only very few vector subscripts, it
shouldn't matter too much.

Additionally, I expect that one either has only very few elements - or one uses
A([array]) which is not compile-time checkable.

The only case where one might have a lot of elements in the vector is in
generated code - but that looks as a very, very special case for which one does
not need to performance optimize, I'd guess.


Side note: I tried your example with NAG f95 5.1 (of 2007) - and it does not
detect the issue - neither at compile nor at runtime (-C=all).


  parent reply	other threads:[~2013-07-28 11:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-28  9:55 [Bug fortran/58009] New: " tkoenig at gcc dot gnu.org
2013-07-28 10:23 ` [Bug fortran/58009] " dominiq at lps dot ens.fr
2013-07-28 11:25 ` burnus at gcc dot gnu.org [this message]
2013-07-28 12:38 ` tkoenig at gcc dot gnu.org
2013-07-28 21:16 ` tkoenig at gcc dot gnu.org

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