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* [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled
@ 2012-04-27  9:27 bonzini at gnu dot org
  2012-04-27  9:30 ` [Bug target/53138] " bonzini at gnu dot org
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: bonzini at gnu dot org @ 2012-04-27  9:27 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

             Bug #: 53138
           Summary: [4.7/4.8 Regression] spaceship operator miscompiled
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: bonzini@gnu.org
        ReportedBy: bonzini@gnu.org
            Target: x86_64-pc-linux-gnu


This program is miscompiled at -O2:

typedef struct sreal
{
  unsigned sig;        /* Significant.  */
  int exp;        /* Exponent.  */
} sreal;

sreal_compare (sreal *a, sreal *b)
{
  if (a->exp > b->exp)
    return 1;
  if (a->exp < b->exp)
    return -1;
  if (a->sig > b->sig)
    return 1;
  return -(a->sig < b->sig);
}

sreal a[] = {
   { 0, 0 },
   { 1, 0 },
   { 0, 1 },
   { 1, 1 }
};

int main()
{
  int i, j;
  for (i = 0; i <= 3; i++) {
    for (j = 0; j < 3; j++) {
      if (i < j && sreal_compare(&a[i], &a[j]) != -1) abort();
      if (i == j && sreal_compare(&a[i], &a[j]) != 0) abort();
      if (i > j && sreal_compare(&a[i], &a[j]) != 1) abort();
    }
  }
}

The problem is that the comparison on sig is compiled to this:

    movl    (%rsi), %ecx
    cmpl    %ecx, (%rdi)
    sbbl    %edx, %edx
    cmovbe    %edx, %eax
    ret

but sbbl only preserves the carry flag, not the zero flag.


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7/4.8 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
@ 2012-04-27  9:30 ` bonzini at gnu dot org
  2012-04-27 10:41 ` rguenth at gcc dot gnu.org
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: bonzini at gnu dot org @ 2012-04-27  9:30 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

Paolo Bonzini <bonzini at gnu dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-04-27
     Ever Confirmed|0                           |1


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7/4.8 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
  2012-04-27  9:30 ` [Bug target/53138] " bonzini at gnu dot org
@ 2012-04-27 10:41 ` rguenth at gcc dot gnu.org
  2012-04-27 12:18 ` bonzini at gnu dot org
                   ` (4 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-04-27 10:41 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.7.1


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7/4.8 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
  2012-04-27  9:30 ` [Bug target/53138] " bonzini at gnu dot org
  2012-04-27 10:41 ` rguenth at gcc dot gnu.org
@ 2012-04-27 12:18 ` bonzini at gnu dot org
  2012-04-30  8:58 ` [Bug target/53138] [4.7 " uros at gcc dot gnu.org
                   ` (3 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: bonzini at gnu dot org @ 2012-04-27 12:18 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

--- Comment #1 from Paolo Bonzini <bonzini at gnu dot org> 2012-04-27 12:18:03 UTC ---
Author: bonzini
Date: Fri Apr 27 12:17:50 2012
New Revision: 186904

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186904
Log:
2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

        PR target/53138
        * config/i386/i386.md (x86_mov<mode>cc_0_m1_neg): Add clobber.

testsuite:
2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

        PR target/53138
        * gcc.c-torture/execute/20120427-1.c: New testcase.



Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/20120427-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.md
    trunk/gcc/testsuite/ChangeLog


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
                   ` (2 preceding siblings ...)
  2012-04-27 12:18 ` bonzini at gnu dot org
@ 2012-04-30  8:58 ` uros at gcc dot gnu.org
  2012-04-30  9:56 ` uros at gcc dot gnu.org
                   ` (2 subsequent siblings)
  6 siblings, 0 replies; 8+ messages in thread
From: uros at gcc dot gnu.org @ 2012-04-30  8:58 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

--- Comment #2 from uros at gcc dot gnu.org 2012-04-30 08:57:45 UTC ---
Author: uros
Date: Mon Apr 30 08:57:41 2012
New Revision: 186962

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186962
Log:
    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * config/i386/i386.md (x86_mov<mode>cc_0_m1_neg): Add clobber.

testsuite/ChangeLog:

    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * gcc.c-torture/execute/20120427-1.c: New testcase.


Added:
    branches/gcc-4_7-branch/gcc/testsuite/gcc.c-torture/execute/20120427-1.c
Modified:
    branches/gcc-4_7-branch/gcc/ChangeLog
    branches/gcc-4_7-branch/gcc/config/i386/i386.md
    branches/gcc-4_7-branch/gcc/testsuite/ChangeLog


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
                   ` (3 preceding siblings ...)
  2012-04-30  8:58 ` [Bug target/53138] [4.7 " uros at gcc dot gnu.org
@ 2012-04-30  9:56 ` uros at gcc dot gnu.org
  2012-04-30 10:23 ` uros at gcc dot gnu.org
  2012-04-30 10:27 ` ubizjak at gmail dot com
  6 siblings, 0 replies; 8+ messages in thread
From: uros at gcc dot gnu.org @ 2012-04-30  9:56 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

--- Comment #3 from uros at gcc dot gnu.org 2012-04-30 09:56:31 UTC ---
Author: uros
Date: Mon Apr 30 09:56:27 2012
New Revision: 186963

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186963
Log:
    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * config/i386/i386.md (x86_mov<mode>cc_0_m1_neg): Add clobber.

testsuite/ChangeLog:

    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * gcc.c-torture/execute/20120427-1.c: New testcase.


Added:
    branches/gcc-4_6-branch/gcc/testsuite/gcc.c-torture/execute/20120427-1.c
Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/config/i386/i386.md
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
                   ` (4 preceding siblings ...)
  2012-04-30  9:56 ` uros at gcc dot gnu.org
@ 2012-04-30 10:23 ` uros at gcc dot gnu.org
  2012-04-30 10:27 ` ubizjak at gmail dot com
  6 siblings, 0 replies; 8+ messages in thread
From: uros at gcc dot gnu.org @ 2012-04-30 10:23 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

--- Comment #4 from uros at gcc dot gnu.org 2012-04-30 10:22:44 UTC ---
Author: uros
Date: Mon Apr 30 10:22:39 2012
New Revision: 186964

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=186964
Log:
    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * config/i386/i386.md (x86_mov<mode>cc_0_m1_neg): Add clobber.

testsuite/ChangeLog:

    Backport from mainline
    2012-04-27  Paolo Bonzini  <bonzini@gnu.org>

    PR target/53138
    * gcc.c-torture/execute/20120427-1.c: New testcase.


Added:
    branches/gcc-4_5-branch/gcc/testsuite/gcc.c-torture/execute/20120427-1.c
Modified:
    branches/gcc-4_5-branch/gcc/ChangeLog
    branches/gcc-4_5-branch/gcc/config/i386/i386.md
    branches/gcc-4_5-branch/gcc/testsuite/ChangeLog


^ permalink raw reply	[flat|nested] 8+ messages in thread
* [Bug target/53138] [4.7 Regression] spaceship operator miscompiled
  2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
                   ` (5 preceding siblings ...)
  2012-04-30 10:23 ` uros at gcc dot gnu.org
@ 2012-04-30 10:27 ` ubizjak at gmail dot com
  6 siblings, 0 replies; 8+ messages in thread
From: ubizjak at gmail dot com @ 2012-04-30 10:27 UTC (permalink / raw)
  To: gcc-bugs

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53138

Uros Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                URL|                            |http://gcc.gnu.org/ml/gcc-p
                   |                            |atches/2012-04/msg01745.htm
                   |                            |l
         Resolution|                            |FIXED
   Target Milestone|4.7.1                       |4.5.4

--- Comment #5 from Uros Bizjak <ubizjak at gmail dot com> 2012-04-30 10:26:48 UTC ---
Fixed in 4.5.4+.


^ permalink raw reply	[flat|nested] 8+ messages in thread
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2012-04-27  9:27 [Bug target/53138] New: [4.7/4.8 Regression] spaceship operator miscompiled bonzini at gnu dot org
2012-04-27  9:30 ` [Bug target/53138] " bonzini at gnu dot org
2012-04-27 10:41 ` rguenth at gcc dot gnu.org
2012-04-27 12:18 ` bonzini at gnu dot org
2012-04-30  8:58 ` [Bug target/53138] [4.7 " uros at gcc dot gnu.org
2012-04-30  9:56 ` uros at gcc dot gnu.org
2012-04-30 10:23 ` uros at gcc dot gnu.org
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