[Bug c/47837] New: FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[Bug c/47837] New: FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[danglin at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

           Summary: FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for
                    bogus messages, line 26)
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: danglin@gcc.gnu.org
              Host: hppa1.1-hp-hpux10.20
            Target: hppa1.1-hp-hpux10.20
             Build: hppa1.1-hp-hpux10.20


Executing on host: /xxx/gnu/gcc/objdir/gcc/xgcc -B/xxx/gnu/gcc/objdir/gcc/
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c   -Wuninitialized -O2
-S  -o 
uninit-pred-7_a.s    (timeout = 300)
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c: In function
'foo':/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c:26:11: warning:
'v' may 
be used uninitialized in this function [-Wuninitialized]
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c: In function 'foo_2':
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c:48:12: warning: 'v' may
be used uninitialized in this function [-Wuninitialized]
output is:
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c: In function
'foo':/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c:26:11: warning:
'v' may 
be used uninitialized in this function [-Wuninitialized]
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c: In function 'foo_2':
/xxx/gnu/gcc/gcc/gcc/testsuite/gcc.dg/uninit-pred-7_a.c:48:12: warning: 'v' may 
be used uninitialized in this function [-Wuninitialized]

PASS: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 20)
PASS: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 23)
FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)
PASS: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 42)
PASS: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 45)
PASS: gcc.dg/uninit-pred-7_a.c warning (test for warnings, line 48)
PASS: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 51)
PASS: gcc.dg/uninit-pred-7_a.c (test for excess errors)

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

Andreas Krebbel <krebbel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|hppa1.1-hp-hpux10.20        |hppa1.1-hp-hpux10.20,
                   |                            |s390x-ibm-linux
                 CC|                            |krebbel at gcc dot gnu.org
               Host|hppa1.1-hp-hpux10.20        |hppa1.1-hp-hpux10.20,
                   |                            |s390x-ibm-linux
              Build|hppa1.1-hp-hpux10.20        |hppa1.1-hp-hpux10.20,
                   |                            |s390x-ibm-linux

--- Comment #1 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-03 12:43:34 UTC ---
I see the same on s390x.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #2 from davidxl <xinliangli at gmail dot com> 2011-03-03 17:32:06 UTC ---
Please attach two dump files:

-fdump-tree-cddce2-blocks
-fdump-tree-uninit-details


David

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #4 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-03 17:39:12 UTC ---
Created attachment 23536
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23536
uninit-pred-7_a.c.128t.uninit

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #3 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-03 17:38:48 UTC ---
Created attachment 23535
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23535
uninit-pred-7_a.c.126t.cddce2

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #5 from davidxl <xinliangli at gmail dot com> 2011-03-03 18:06:33 UTC ---
While this exposes a limitation in uninit analysis, the cause of the warning is
that C FE behaves differently. On x86, the expression "n || l" is converted to
bitwise | expression, but on s390, it is not.  Any reason why it is the case?

David

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-03-03 18:36:58 UTC ---
(In reply to comment #5)
> While this exposes a limitation in uninit analysis, the cause of the warning is
> that C FE behaves differently. On x86, the expression "n || l" is converted to
> bitwise | expression, but on s390, it is not.  Any reason why it is the case?
> 
> David

Because of BRANCH_COST is different.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #7 from davidxl <xinliangli at gmail dot com> 2011-03-07 08:40:29 UTC ---
Created attachment 23566
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23566
Patch

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #8 from davidxl <xinliangli at gmail dot com> 2011-03-07 08:41:25 UTC ---
Please verify the patch on hpux and os390.

Thanks,

David

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #9 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-07 11:47:47 UTC ---
(In reply to comment #8)
> Please verify the patch on hpux and os390.

Your patch works! It fixes uninit-pred-7_a.c on s390 and s390x.

Thanks!

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #10 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-07 15:59:46 UTC ---
(In reply to comment #8)
> Please verify the patch on hpux and os390.

Perhaps you could enhance your patch to cover then uninit-pred-8_a.c case as
well. It looks quite similiar:

/build3/gcc-head-build/gcc/xgcc -B/build3/gcc-head-build/gcc/
/build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c   -Wuninitialized -O2
-S  -o uninit-pred-8_a.s

/build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c: In function ‘foo’:
/build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c:26:11: warning: ‘v’ may
be used uninitialized in this function [-Wuninitialized]
/build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c: In function ‘foo_2’:
/build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c:42:11: warning: ‘v’ may
be used uninitialized in this function [-Wuninitialized]

As well as with uninit-pred-7_a.c the first warning is unexpected.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #11 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-07 16:01:09 UTC ---
Created attachment 23572
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23572
uninit-pred-8_a.c.126t.cddce2

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #12 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-07 16:01:37 UTC ---
Created attachment 23573
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23573
uninit-pred-8_a.c.128t.uninit

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #13 from davidxl <xinliangli at gmail dot com> 2011-03-07 16:58:03 UTC ---
Yes -- I also wanted to do the generalization.

David

(In reply to comment #10)
> (In reply to comment #8)
> > Please verify the patch on hpux and os390.
> 
> Perhaps you could enhance your patch to cover then uninit-pred-8_a.c case as
> well. It looks quite similiar:
> 
> /build3/gcc-head-build/gcc/xgcc -B/build3/gcc-head-build/gcc/
> /build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c   -Wuninitialized -O2
> -S  -o uninit-pred-8_a.s
> 
> /build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c: In function ‘foo’:
> /build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c:26:11: warning: ‘v’ may
> be used uninitialized in this function [-Wuninitialized]
> /build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c: In function ‘foo_2’:
> /build3/gcc-head/gcc/testsuite/gcc.dg/uninit-pred-8_a.c:42:11: warning: ‘v’ may
> be used uninitialized in this function [-Wuninitialized]
> 
> As well as with uninit-pred-7_a.c the first warning is unexpected.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

Mikael Pettersson <mikpe at it dot uu.se> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mikpe at it dot uu.se

--- Comment #14 from Mikael Pettersson <mikpe at it dot uu.se> 2011-03-07 18:59:12 UTC ---
uninit-pred-7_a.c and uninit-pred-8_a.c fail in the same way on m68k-linux. 
The proposed patch fixes the unexpected warning in uninit-pred-7_a.c on m68k
but not the one in uninit-pred-8_a.c.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #15 from davidxl <xinliangli at gmail dot com> 2011-03-08 00:25:29 UTC ---
Created attachment 23581
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23581
patch2


Please validate the more generalized patch.

David

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[xinliangli at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #16 from davidxl <xinliangli at gmail dot com> 2011-03-08 00:26:47 UTC ---
The second patch should work for the two cases (verified with -mbranch-cost=0
on x86).

David

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #17 from Mikael Pettersson <mikpe at it dot uu.se> 2011-03-08 11:07:44 UTC ---
The second patch fixes both test cases on m68k-linux.

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[krebbel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

--- Comment #18 from Andreas Krebbel <krebbel at gcc dot gnu.org> 2011-03-08 14:40:45 UTC ---
(In reply to comment #15)
> Created attachment 23581 [details]
> patch2
> Please validate the more generalized patch.

Bootstraps and works on s390x for both testcases. Thanks!

[Bug c/47837] FAIL: gcc.dg/uninit-pred-7_a.c bogus warning (test for bogus messages, line 26)

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47837

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |mpolacek at gcc dot gnu.org
         Resolution|---                         |FIXED

--- Comment #19 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Looks fixed then.