[Bug c/38781] New: PR38151: valgrind finds problem

[Bug c/38781] New: PR38151: valgrind finds problem

[dcb314 at hotmail dot com]

In the testsuite for C is the file gcc.c-torture/execute/pr38151.c

I just tried to compile this file with the GNU C compiler
version 4.4 snapshot 20090102 using valgrind.

The debug output was

==32071== Conditional jump or move depends on uninitialised value(s)
==32071==    at 0x8A1544: merge_classes (i386.c:4787)
==32071==    by 0x8A69D6: classify_argument (i386.c:4912)
==32071==    by 0x8A727C: construct_container (i386.c:5205)
==32071==    by 0x8B1283: ix86_gimplify_va_arg (i386.c:6633)
==32071==    by 0x4BE4FA: gimplify_va_arg_expr (builtins.c:5025)
==32071==    by 0x5FE7F5: gimplify_expr (gimplify.c:6361)
==32071==    by 0x613B69: gimplify_modify_expr (gimplify.c:4230)
==32071==    by 0x5FDE09: gimplify_expr (gimplify.c:6333)

I've had a quick look at the code, and I suspect that
some array index checking around line 4912 of i386.c
might help.

This bug report may be related to the original source of
this code, pr38151.


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           Summary: PR38151: valgrind finds problem
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: dcb314 at hotmail dot com
  GCC host triplet: x86_64-suse-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug c/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

------- Comment #1 from hjl dot tools at gmail dot com  2009-01-09 17:57 -------
A patch is posted at

http://gcc.gnu.org/ml/gcc-patches/2009-01/msg00463.html


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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |http://gcc.gnu.org/ml/gcc-
                   |                            |patches/2009-
                   |                            |01/msg00463.html
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-01-09 17:57:21
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug c/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   GCC host triplet|x86_64-suse-linux           |
 GCC target triplet|                            |x86_64-*-linux-gnu
   Target Milestone|---                         |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

------- Comment #2 from hjl dot tools at gmail dot com  2009-01-14 15:16 -------
An updated patch is posted at

http://gcc.gnu.org/ml/gcc-patches/2009-01/msg00738.html


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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|http://gcc.gnu.org/ml/gcc-  |http://gcc.gnu.org/ml/gcc-
                   |patches/2009-               |patches/2009-
                   |01/msg00463.html            |01/msg00738.html


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

------- Comment #3 from hjl dot tools at gmail dot com  2009-01-14 17:07 -------
An updated patch is at

http://gcc.gnu.org/ml/gcc-patches/2009-01/msg00747.html


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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|http://gcc.gnu.org/ml/gcc-  |http://gcc.gnu.org/ml/gcc-
                   |patches/2009-               |patches/2009-
                   |01/msg00738.html            |01/msg00747.html


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[dcb314 at hotmail dot com]

------- Comment #4 from dcb314 at hotmail dot com  2009-01-15 21:51 -------
(In reply to comment #3)
> An updated patch is at
> 
> http://gcc.gnu.org/ml/gcc-patches/2009-01/msg00747.html

I have a couple of minor questions about the coding style
of this patch.

1. Why is the "/ 8 / 8" a good idea ? 

Presumably "/ 64" doesn't do it right ?

2. On the middle condition of the for-loop, could it
be micro-optimised to compute the upper limit of the
for loop before the loop starts ?

For example, instead of

; (i < A) && (i + pos) < B; ++i

replace with 

const int limit = min( A, B - pos);

...

; i < limit; ++i


Just an idea.


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dcb314 at hotmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dcb314 at hotmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

------- Comment #5 from hjl dot tools at gmail dot com  2009-03-29 19:33 -------
The updated patch is at

http://gcc.gnu.org/ml/gcc-patches/2009-03/msg01581.html


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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ubizjak at gmail dot com
                URL|http://gcc.gnu.org/ml/gcc-  |http://gcc.gnu.org/ml/gcc-
                   |patches/2009-               |patches/2009-
                   |01/msg00747.html            |03/msg01581.html


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[hjl at gcc dot gnu dot org]

------- Comment #6 from hjl at gcc dot gnu dot org  2009-03-30 14:29 -------
Subject: Bug 38781

Author: hjl
Date: Mon Mar 30 14:29:10 2009
New Revision: 145292

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=145292
Log:
2008-03-30  H.J. Lu  <hongjiu.lu@intel.com>

        PR target/38781
        * config/i386/i386.c (classify_argument): Check total size of
        structure.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[hjl dot tools at gmail dot com]

------- Comment #7 from hjl dot tools at gmail dot com  2009-03-30 14:33 -------
Fixed for 4.5.0. No plan to back port.


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hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.4.0                       |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781

[Bug target/38781] PR38151: valgrind finds problem

[lauras at gcc dot gnu dot org]

------- Comment #8 from lauras at gcc dot gnu dot org  2009-04-24 05:50 -------
*** Bug 34865 has been marked as a duplicate of this bug. ***


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lauras at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hp at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38781