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From: Michael Ubell <ubell@mindspring.com> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, Subject: Re: c/10339: strncmp generates imPure code Date: Mon, 07 Apr 2003 19:06:00 -0000 [thread overview] Message-ID: <20030407190602.24623.qmail@sources.redhat.com> (raw) The following reply was made to PR optimization/10339; it has been noted by GNATS. From: Michael Ubell <ubell@mindspring.com> To: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de> Cc: Wolfgang Bangerth <bangerth@ices.utexas.edu>, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org Subject: Re: c/10339: strncmp generates imPure code Date: Mon, 07 Apr 2003 12:05:31 -0700 > I suspect the extra byte read is actually not relevant for the result, > and because of alignment, gcc knows the second problem cannot occur, > but I have neither a SPARC nor SPARC knowledge to test that. > Actually if you make the compare string longer you can get it to look at an arbitrary number of bytes passed the allocated part, so I think this could fault if you set it up right. Also in the original problem, the first argument was not allocated locally so the compiler would have no idea how big or what its alignment was. (In fact it was in a loop comparing strings from an array.)
next reply other threads:[~2003-04-07 19:06 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2003-04-07 19:06 Michael Ubell [this message] -- strict thread matches above, loose matches on Subject: below -- 2003-04-08 1:56 Hans-Peter Nilsson 2003-04-07 21:46 Michael Ubell 2003-04-07 21:46 Andreas Schwab 2003-04-07 21:36 Michael Ubell 2003-04-07 21:26 Andreas Schwab 2003-04-07 20:56 Michael Ubell 2003-04-07 20:06 Andreas Schwab 2003-04-07 20:06 Michael Ubell 2003-04-07 19:56 Michael Ubell 2003-04-07 19:36 Andreas Schwab 2003-04-07 19:36 Falk Hueffner 2003-04-07 19:06 Falk Hueffner 2003-04-07 18:16 Wolfgang Bangerth 2003-04-07 17:06 Michael Ubell 2003-04-07 16:48 bangerth 2003-04-07 16:16 ubell
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