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* [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying
@ 2006-03-10 12:50 cyp561 at gmail dot com
2006-03-10 12:57 ` [Bug middle-end/26630] [4.0 Regression] " pinskia at gcc dot gnu dot org
` (9 more replies)
0 siblings, 10 replies; 11+ messages in thread
From: cyp561 at gmail dot com @ 2006-03-10 12:50 UTC (permalink / raw)
To: gcc-bugs
As far as I can tell, c1 should be equal to 80000, not -51072, or at least
equal to c2.
Sorry if I'm mistaken, but I can't see how c1 and c2 can be different. The
result is the same using gcc 3.3.6, gcc 3.4.4 and gcc 4.0.2.
Program (error.c):
---------
#include <stdio.h>
int main()
{
int a1 = 40000;
#define b1 ((int)(short)(a1-10000))
int c1 = ( b1 +10000)*2;
int a2 = 40000;
int b2 = ((int)(short)(a2-10000));
int c2 = ( b2 +10000)*2;
printf("sizeof(int) = %d, sizeof(short) = %d\na1 = %d, b1 = %d, c1 = %d\na2
= %d, b2 = %d, c2 = %d (c1 and c2 should both be 80000)\n",
sizeof(int), sizeof(short), a1, b1, c1,
a2, b2, c2);
if( c1!=80000 || c2!=80000 )
{
printf("Error!\n");
return 1;
}
return 0;
}
----------
Output:
j@gentoo ~/tmp $ cat /proc/version
Linux version 2.6.15-gentoo-r1 (root@gentoo) (gcc version 3.3.6 (Gentoo 3.3.6,
ssp-3.3.6-1.0, pie-8.7.8)) #1 PREEMPT Wed Jan 25 11:58:26 CET 2006
j@gentoo ~/tmp $ gcc-3.3.6 -v
Reading specs from /usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/specs
Configured with: /var/tmp/portage/gcc-3.3.6/work/gcc-3.3.6/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/3.3.6
--includedir=/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3.6
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3.6/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/3.3.6/info
--with-gxx-include-dir=/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.6/include/g++-v3
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --disable-multilib
--disable-libgcj --enable-languages=c,c++,f77 --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)
j@gentoo ~/tmp $ gcc-3.3.6 -o error error.c -Wall
j@gentoo ~/tmp $ ./error
sizeof(int) = 4, sizeof(short) = 2
a1 = 40000, b1 = 30000, c1 = -51072
a2 = 40000, b2 = 30000, c2 = 80000 (c1 and c2 should both be 80000)
Error!
j@gentoo ~/tmp $ gcc-3.4.4 -v
Reading specs from /usr/lib/gcc/i686-pc-linux-gnu/3.4.4/specs
Configured with: /var/tmp/portage/gcc-3.4.4-r1/work/gcc-3.4.4/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/3.4.4
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/3.4.4/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.4
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.4/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/3.4.4/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/3.4.4/include/g++-v3
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --disable-multilib
--disable-libmudflap --disable-libgcj --enable-languages=c,c++,f77
--enable-shared --enable-threads=posix --enable-__cxa_atexit
--enable-clocale=gnu
Thread model: posix
gcc version 3.4.4 (Gentoo 3.4.4-r1, ssp-3.4.4-1.0, pie-8.7.8)
j@gentoo ~/tmp $ gcc-3.4.4 -o error error.c -Wall
j@gentoo ~/tmp $ ./error
sizeof(int) = 4, sizeof(short) = 2
a1 = 40000, b1 = 30000, c1 = -51072
a2 = 40000, b2 = 30000, c2 = 80000 (c1 and c2 should both be 80000)
Error!
j@gentoo ~/tmp $ gcc-4.0.2 -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /var/tmp/portage/gcc-4.0.2-r3/work/gcc-4.0.2/configure
--prefix=/usr --bindir=/usr/i686-pc-linux-gnu/gcc-bin/4.0.2
--includedir=/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include
--datadir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2
--mandir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2/man
--infodir=/usr/share/gcc-data/i686-pc-linux-gnu/4.0.2/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-linux-gnu/4.0.2/include/g++-v4
--host=i686-pc-linux-gnu --build=i686-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --disable-multilib
--disable-libmudflap --disable-libgcj --enable-languages=c,c++,f95
--enable-shared --enable-threads=posix --enable-__cxa_atexit
--enable-clocale=gnu
Thread model: posix
gcc version 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
j@gentoo ~/tmp $ gcc-4.0.2 -o error error.c -Wall
j@gentoo ~/tmp $ ./error
sizeof(int) = 4, sizeof(short) = 2
a1 = 40000, b1 = 30000, c1 = -51072
a2 = 40000, b2 = 30000, c2 = 80000 (c1 and c2 should both be 80000)
Error!
j@gentoo ~/tmp $
--
Summary: Incorrect result when subtracting, casting to short and
back to int, adding and multiplying
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: cyp561 at gmail dot com
GCC build triplet: i686-pc-linux-gnu-gcc-3.3.6
GCC host triplet: i686-pc-linux-gnu-gcc-3.3.6
GCC target triplet: i686-pc-linux-gnu-gcc-3.3.6
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
@ 2006-03-10 12:57 ` pinskia at gcc dot gnu dot org
2006-03-10 13:52 ` rguenth at gcc dot gnu dot org
` (8 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-03-10 12:57 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from pinskia at gcc dot gnu dot org 2006-03-10 12:57 -------
Confirmed, just a regression on the 4.0 branch, 3.4.6 was the last release of
the 3.4 branch.
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Component|c |middle-end
Ever Confirmed|0 |1
Keywords| |wrong-code
Known to fail| |3.4.0 4.0.0 4.0.3 3.3.3
| |3.0.4
Known to work| |2.95.3 4.1.0 4.2.0
Last reconfirmed|0000-00-00 00:00:00 |2006-03-10 12:57:24
date| |
Summary|Incorrect result when |[4.0 Regression] Incorrect
|subtracting, casting to |result when subtracting,
|short and back to int, |casting to short and back to
|adding and multiplying |int, adding and multiplying
Target Milestone|--- |4.0.4
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
2006-03-10 12:57 ` [Bug middle-end/26630] [4.0 Regression] " pinskia at gcc dot gnu dot org
@ 2006-03-10 13:52 ` rguenth at gcc dot gnu dot org
2006-03-10 13:53 ` rguenth at gcc dot gnu dot org
` (7 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-10 13:52 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rguenth at gcc dot gnu dot org 2006-03-10 13:52 -------
We fold
((intD.0) ((short intD.7) a1D.1133 - 10000) + 10000) * 2
via extract_muldiv to
(intD.0) (short intD.7) a1D.1133 * 2
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu dot
| |org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
2006-03-10 12:57 ` [Bug middle-end/26630] [4.0 Regression] " pinskia at gcc dot gnu dot org
2006-03-10 13:52 ` rguenth at gcc dot gnu dot org
@ 2006-03-10 13:53 ` rguenth at gcc dot gnu dot org
2006-03-10 14:31 ` rguenth at gcc dot gnu dot org
` (6 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-10 13:53 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from rguenth at gcc dot gnu dot org 2006-03-10 13:53 -------
shorter testcase:
extern void abort(void);
int main()
{
int a1 = 40000;
int c1 = ( ((int)(short)(a1-10000)) + 10000)*2;
if (c1 != 80000)
abort();
return 0;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (2 preceding siblings ...)
2006-03-10 13:53 ` rguenth at gcc dot gnu dot org
@ 2006-03-10 14:31 ` rguenth at gcc dot gnu dot org
2006-03-10 16:17 ` rguenth at gcc dot gnu dot org
` (5 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-10 14:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from rguenth at gcc dot gnu dot org 2006-03-10 14:31 -------
with 4.1 we start with
((intD.0) (short intD.7) ((short unsigned intD.8) a1D.1280 - 10000) + 10000) *
2
which convert builds from converting a - 10000 to short:
(short intD.7) ((short unsigned intD.8) a1D.1280 - 10000)
this prevents the (now latent) problem in extract_muldiv to show up.
I believe
case CONVERT_EXPR: case NON_LVALUE_EXPR: case NOP_EXPR:
/* If op0 is an expression ... */
if ((COMPARISON_CLASS_P (op0)
|| UNARY_CLASS_P (op0)
|| BINARY_CLASS_P (op0)
|| EXPRESSION_CLASS_P (op0))
/* ... and is unsigned, and its type is smaller than ctype,
then we cannot pass through as widening. */
&& ((TYPE_UNSIGNED (TREE_TYPE (op0))
&& ! (TREE_CODE (TREE_TYPE (op0)) == INTEGER_TYPE
&& TYPE_IS_SIZETYPE (TREE_TYPE (op0)))
&& (GET_MODE_SIZE (TYPE_MODE (ctype))
> GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0)))))
/* ... or this is a truncation (t is narrower than op0),
then we cannot pass through this narrowing. */
|| (GET_MODE_SIZE (TYPE_MODE (type))
< GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (op0))))
the last check needs to read !=, but this extract_muldiv looks like a mess...
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (3 preceding siblings ...)
2006-03-10 14:31 ` rguenth at gcc dot gnu dot org
@ 2006-03-10 16:17 ` rguenth at gcc dot gnu dot org
2006-03-10 16:25 ` patchapp at dberlin dot org
` (4 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-10 16:17 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from rguenth at gcc dot gnu dot org 2006-03-10 16:17 -------
The patch from 25125 fixes the problem.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |25125
AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot
|dot org |org
Status|NEW |ASSIGNED
GCC build triplet|i686-pc-linux-gnu-gcc-3.3.6 |
GCC host triplet|i686-pc-linux-gnu-gcc-3.3.6 |
GCC target triplet|i686-pc-linux-gnu-gcc-3.3.6 |
Last reconfirmed|2006-03-10 12:57:24 |2006-03-10 16:17:24
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (4 preceding siblings ...)
2006-03-10 16:17 ` rguenth at gcc dot gnu dot org
@ 2006-03-10 16:25 ` patchapp at dberlin dot org
2006-03-13 9:02 ` rguenth at gcc dot gnu dot org
` (3 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: patchapp at dberlin dot org @ 2006-03-10 16:25 UTC (permalink / raw)
To: gcc-bugs
------- Comment #6 from patchapp at dberlin dot org 2006-03-10 16:25 -------
Subject: Bug number PR26630
A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-03/msg00616.html
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (5 preceding siblings ...)
2006-03-10 16:25 ` patchapp at dberlin dot org
@ 2006-03-13 9:02 ` rguenth at gcc dot gnu dot org
2006-03-13 9:09 ` rguenth at gcc dot gnu dot org
` (2 subsequent siblings)
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-13 9:02 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from rguenth at gcc dot gnu dot org 2006-03-13 09:02 -------
Subject: Bug 26630
Author: rguenth
Date: Mon Mar 13 09:02:40 2006
New Revision: 111990
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=111990
Log:
2006-03-13 Richard Guenther <rguenther@suse.de>
PR middle-end/26630
* gcc.dg/torture/pr26630.c: New testcase.
Added:
trunk/gcc/testsuite/gcc.dg/torture/pr26630.c
Modified:
trunk/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (6 preceding siblings ...)
2006-03-13 9:02 ` rguenth at gcc dot gnu dot org
@ 2006-03-13 9:09 ` rguenth at gcc dot gnu dot org
2006-06-09 10:35 ` rguenth at gcc dot gnu dot org
2007-02-03 16:23 ` gdr at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-03-13 9:09 UTC (permalink / raw)
To: gcc-bugs
------- Comment #8 from rguenth at gcc dot gnu dot org 2006-03-13 09:09 -------
Subject: Bug 26630
Author: rguenth
Date: Mon Mar 13 09:09:13 2006
New Revision: 111992
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=111992
Log:
2006-03-13 Richard Guenther <rguenther@suse.de>
PR middle-end/26630
* gcc.dg/torture/pr26630.c: New testcase.
Added:
branches/gcc-4_1-branch/gcc/testsuite/gcc.dg/torture/pr26630.c
Modified:
branches/gcc-4_1-branch/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (7 preceding siblings ...)
2006-03-13 9:09 ` rguenth at gcc dot gnu dot org
@ 2006-06-09 10:35 ` rguenth at gcc dot gnu dot org
2007-02-03 16:23 ` gdr at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-06-09 10:35 UTC (permalink / raw)
To: gcc-bugs
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|rguenth at gcc dot gnu dot |unassigned at gcc dot gnu
|org |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
* [Bug middle-end/26630] [4.0 Regression] Incorrect result when subtracting, casting to short and back to int, adding and multiplying
2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
` (8 preceding siblings ...)
2006-06-09 10:35 ` rguenth at gcc dot gnu dot org
@ 2007-02-03 16:23 ` gdr at gcc dot gnu dot org
9 siblings, 0 replies; 11+ messages in thread
From: gdr at gcc dot gnu dot org @ 2007-02-03 16:23 UTC (permalink / raw)
To: gcc-bugs
------- Comment #9 from gdr at gcc dot gnu dot org 2007-02-03 16:23 -------
Fixed in GCC-4.1.0.
--
gdr at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
Target Milestone|4.0.4 |4.1.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26630
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2007-02-03 16:23 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
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2006-03-10 12:50 [Bug c/26630] New: Incorrect result when subtracting, casting to short and back to int, adding and multiplying cyp561 at gmail dot com
2006-03-10 12:57 ` [Bug middle-end/26630] [4.0 Regression] " pinskia at gcc dot gnu dot org
2006-03-10 13:52 ` rguenth at gcc dot gnu dot org
2006-03-10 13:53 ` rguenth at gcc dot gnu dot org
2006-03-10 14:31 ` rguenth at gcc dot gnu dot org
2006-03-10 16:17 ` rguenth at gcc dot gnu dot org
2006-03-10 16:25 ` patchapp at dberlin dot org
2006-03-13 9:02 ` rguenth at gcc dot gnu dot org
2006-03-13 9:09 ` rguenth at gcc dot gnu dot org
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