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From: "wad at infinet dot ru" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/66090] Wrong loop code generation with -O2 on ARM
Date: Tue, 02 Jun 2015 09:45:00 -0000	[thread overview]
Message-ID: <bug-66090-4-Z5kiWhrJPV@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-66090-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66090

--- Comment #10 from Andrew <wad at infinet dot ru> ---
(In reply to Christian Prochaska from comment #0)
> test.c:
> 
> void func()
> {
>     unsigned int i;
> 
>     unsigned int *ptr = (unsigned int*)0xfffff000;
> 
>     for (i = 0; i < 1024; i++)
>         *(ptr++) = 0;
> }

There is no attempts to check pointer for NULL.
But, this is hidden attempt to substitute one test (i < 1024) to another (ptr
!= NULL), which will be the result of unexpected "always true".

And by the way:

void *ptr = malloc(1024);

if (ptr == NULL) /* always false ? Never panic()? */
  panic();


  parent reply	other threads:[~2015-06-02  9:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-10  2:28 [Bug c/66090] New: " christian.prochaska@genode-labs.com
2015-05-10 11:09 ` [Bug c/66090] " kugan at gcc dot gnu.org
2015-05-10 21:43 ` pinskia at gcc dot gnu.org
2015-05-12 19:46 ` rearnsha at gcc dot gnu.org
2015-05-13  8:54 ` rguenth at gcc dot gnu.org
2015-05-13  8:54 ` rguenth at gcc dot gnu.org
2015-05-13 15:20 ` joseph at codesourcery dot com
2015-06-02  9:02 ` wad at infinet dot ru
2015-06-02  9:07 ` ktkachov at gcc dot gnu.org
2015-06-02  9:13 ` pinskia at gcc dot gnu.org
2015-06-02  9:45 ` wad at infinet dot ru [this message]
2015-06-22 18:01 ` mpolacek at gcc dot gnu.org

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