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* [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
@ 2009-04-23 13:34 vincent at vinc17 dot org
2009-04-23 13:45 ` [Bug c/39867] " vincent at vinc17 dot org
` (8 more replies)
0 siblings, 9 replies; 10+ messages in thread
From: vincent at vinc17 dot org @ 2009-04-23 13:34 UTC (permalink / raw)
To: gcc-bugs
With GCC 4.4.0, the following program outputs 4294967295 instead of 2:
#include <stdio.h>
int main (void)
{
int exp = -1;
printf ("%u\n", exp < 2 ? 2U : (unsigned int) exp);
return 0;
}
Note: I've tried with gcc-snapshot under a Debian/unstable x86_64 Linux
machine, but the same bug was reported to me, with gcc-4.4.0 (it was found by
Philippe Theveny, who works on MPFR, and the MPFR tests fail because of that).
GCC 4.3.3 does not have this problem.
--
Summary: [4.4 Regression] Wrong result of conditional operator
exp < 2 ? 2U : (unsigned int) exp
Product: gcc
Version: 4.4.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: vincent at vinc17 dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug c/39867] [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
@ 2009-04-23 13:45 ` vincent at vinc17 dot org
2009-04-23 13:46 ` [Bug middle-end/39867] " rguenth at gcc dot gnu dot org
` (7 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: vincent at vinc17 dot org @ 2009-04-23 13:45 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from vincent at vinc17 dot org 2009-04-23 13:44 -------
I forgot to say: the bug occurs whether one compiles with optimizations or not.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
2009-04-23 13:45 ` [Bug c/39867] " vincent at vinc17 dot org
@ 2009-04-23 13:46 ` rguenth at gcc dot gnu dot org
2009-04-23 15:16 ` [Bug middle-end/39867] [4.4/4.5 " bonzini at gnu dot org
` (6 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2009-04-23 13:46 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from rguenth at gcc dot gnu dot org 2009-04-23 13:46 -------
We fold it to
return (int) MAX_EXPR <(unsigned int) exp, 2>;
which is obviously bogus. 4.3 produced
return NON_LVALUE_EXPR <MAX_EXPR <exp, 2>>;
which is correct (well, but has likely mismatched types if the 2 is still
unsigned).
Confirmed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Component|c |middle-end
Ever Confirmed|0 |1
Keywords| |wrong-code
Last reconfirmed|0000-00-00 00:00:00 |2009-04-23 13:46:39
date| |
Target Milestone|--- |4.4.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
2009-04-23 13:45 ` [Bug c/39867] " vincent at vinc17 dot org
2009-04-23 13:46 ` [Bug middle-end/39867] " rguenth at gcc dot gnu dot org
@ 2009-04-23 15:16 ` bonzini at gnu dot org
2009-04-23 15:23 ` bonzini at gnu dot org
` (5 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gnu dot org @ 2009-04-23 15:16 UTC (permalink / raw)
To: gcc-bugs
--
bonzini at gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[4.4 Regression] Wrong |[4.4/4.5 Regression] Wrong
|result of conditional |result of conditional
|operator exp < 2 ? 2U : |operator exp < 2 ? 2U :
|(unsigned int) exp |(unsigned int) exp
Target Milestone|4.4.0 |4.4.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (2 preceding siblings ...)
2009-04-23 15:16 ` [Bug middle-end/39867] [4.4/4.5 " bonzini at gnu dot org
@ 2009-04-23 15:23 ` bonzini at gnu dot org
2009-04-23 15:52 ` bonzini at gnu dot org
` (4 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gnu dot org @ 2009-04-23 15:23 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from bonzini at gnu dot org 2009-04-23 15:22 -------
Created an attachment (id=17684)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17684&action=view)
patch
Bootstrapped but not yet regtested. Testcase:
/* { dg-do link } */
/* { dg-options "-O2" } */
int main (void)
{
int exp = -1;
/* Wrong folding of the LHS to an unsigned MAX leads to 4294967295 > 2. */
if (("%u\n", exp < 2 ? 2U : (unsigned int) exp) > 2)
link_error ();
return 0;
}
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (3 preceding siblings ...)
2009-04-23 15:23 ` bonzini at gnu dot org
@ 2009-04-23 15:52 ` bonzini at gnu dot org
2009-04-24 10:29 ` bonzini at gcc dot gnu dot org
` (3 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gnu dot org @ 2009-04-23 15:52 UTC (permalink / raw)
To: gcc-bugs
--
bonzini at gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|unassigned at gcc dot gnu |bonzini at gnu dot org
|dot org |
Status|NEW |ASSIGNED
Last reconfirmed|2009-04-23 13:46:39 |2009-04-23 15:52:19
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (4 preceding siblings ...)
2009-04-23 15:52 ` bonzini at gnu dot org
@ 2009-04-24 10:29 ` bonzini at gcc dot gnu dot org
2009-04-24 11:35 ` bonzini at gcc dot gnu dot org
` (2 subsequent siblings)
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gcc dot gnu dot org @ 2009-04-24 10:29 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from bonzini at gnu dot org 2009-04-24 10:29 -------
Subject: Bug 39867
Author: bonzini
Date: Fri Apr 24 10:29:18 2009
New Revision: 146695
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=146695
Log:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* fold-const.c (fold_cond_expr_with_comparison): When folding
> and >= to MAX, make sure the MAX uses the same type as the
comparison operands.
testsuite:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* gcc.dg/pr39867.c: New.
Added:
trunk/gcc/testsuite/gcc.dg/pr39867.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/fold-const.c
trunk/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (6 preceding siblings ...)
2009-04-24 11:35 ` bonzini at gcc dot gnu dot org
@ 2009-04-24 11:35 ` bonzini at gnu dot org
2009-06-23 9:44 ` rguenth at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gnu dot org @ 2009-04-24 11:35 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from bonzini at gnu dot org 2009-04-24 11:35 -------
Subject: Bug 39867
Author: bonzini
Date: Fri Apr 24 11:34:59 2009
New Revision: 146702
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=146702
Log:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* fold-const.c (fold_cond_expr_with_comparison): When folding
> and >= to MAX, make sure the MAX uses the same type as the
comparison's operands.
testsuite:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* gcc.dg/pr39867.c: New.
Added:
branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/pr39867.c
- copied unchanged from r146695, trunk/gcc/testsuite/gcc.dg/pr39867.c
Modified:
branches/gcc-4_4-branch/gcc/ChangeLog
branches/gcc-4_4-branch/gcc/fold-const.c
branches/gcc-4_4-branch/gcc/testsuite/ChangeLog
------- Comment #6 from bonzini at gnu dot org 2009-04-24 11:35 -------
committed to both branches.
--
bonzini at gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (5 preceding siblings ...)
2009-04-24 10:29 ` bonzini at gcc dot gnu dot org
@ 2009-04-24 11:35 ` bonzini at gcc dot gnu dot org
2009-04-24 11:35 ` bonzini at gnu dot org
2009-06-23 9:44 ` rguenth at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: bonzini at gcc dot gnu dot org @ 2009-04-24 11:35 UTC (permalink / raw)
To: gcc-bugs
------- Comment #5 from bonzini at gnu dot org 2009-04-24 11:35 -------
Subject: Bug 39867
Author: bonzini
Date: Fri Apr 24 11:34:59 2009
New Revision: 146702
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=146702
Log:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* fold-const.c (fold_cond_expr_with_comparison): When folding
> and >= to MAX, make sure the MAX uses the same type as the
comparison's operands.
testsuite:
2009-04-24 Paolo Bonzini <bonzini@gnu.org>
PR middle-end/39867
* gcc.dg/pr39867.c: New.
Added:
branches/gcc-4_4-branch/gcc/testsuite/gcc.dg/pr39867.c
- copied unchanged from r146695, trunk/gcc/testsuite/gcc.dg/pr39867.c
Modified:
branches/gcc-4_4-branch/gcc/ChangeLog
branches/gcc-4_4-branch/gcc/fold-const.c
branches/gcc-4_4-branch/gcc/testsuite/ChangeLog
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
* [Bug middle-end/39867] [4.4/4.5 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp
2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
` (7 preceding siblings ...)
2009-04-24 11:35 ` bonzini at gnu dot org
@ 2009-06-23 9:44 ` rguenth at gcc dot gnu dot org
8 siblings, 0 replies; 10+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2009-06-23 9:44 UTC (permalink / raw)
To: gcc-bugs
------- Comment #7 from rguenth at gcc dot gnu dot org 2009-06-23 09:43 -------
*** Bug 40524 has been marked as a duplicate of this bug. ***
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |david dot kirkby at onetel
| |dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39867
^ permalink raw reply [flat|nested] 10+ messages in thread
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2009-04-23 13:34 [Bug c/39867] New: [4.4 Regression] Wrong result of conditional operator exp < 2 ? 2U : (unsigned int) exp vincent at vinc17 dot org
2009-04-23 13:45 ` [Bug c/39867] " vincent at vinc17 dot org
2009-04-23 13:46 ` [Bug middle-end/39867] " rguenth at gcc dot gnu dot org
2009-04-23 15:16 ` [Bug middle-end/39867] [4.4/4.5 " bonzini at gnu dot org
2009-04-23 15:23 ` bonzini at gnu dot org
2009-04-23 15:52 ` bonzini at gnu dot org
2009-04-24 10:29 ` bonzini at gcc dot gnu dot org
2009-04-24 11:35 ` bonzini at gcc dot gnu dot org
2009-04-24 11:35 ` bonzini at gnu dot org
2009-06-23 9:44 ` rguenth at gcc dot gnu dot org
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