Re: c/10339: strncmp generates imPure code

[Andreas Schwab <schwab@suse.de>]

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The following reply was made to PR optimization/10339; it has been noted by GNATS.

From: Andreas Schwab <schwab@suse.de>
To: Michael Ubell <ubell@mindspring.com>
Cc: Falk Hueffner <falk.hueffner@student.uni-tuebingen.de>,
	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 22:04:08 +0200

 Michael Ubell <ubell@mindspring.com> writes:
 
 |> Do you mean you want me to set up a case where it runs off the
 |> end of memory?
 
 Yes.
 
 |> I think it is sufficient that it is reading memory
 |> that is not allocated, no?
 
 No, it is not.
 
 |>  If you change the length of the string
 |> in the example you can see that it will read more unallocated
 |> memory.
 
 You haven't provided any evidence yet.  The provided test case is
 correctly translated for the given platform.
 
 |>  Do you have some reason why reading arbirary unallocated
 |> memory is acceptable?  I don't see how the alignment is an issue.
 
 It is.  Memory returned by malloc is required to be correctly aligned for
 any type.
 
 Andreas.
 
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