[Bug libstdc++/48750] New: for_each_template_random_access_ed has unbalanced new/delete[]

[Bug libstdc++/48750] New: for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

           Summary: for_each_template_random_access_ed has unbalanced
                    new/delete[]
           Product: gcc
           Version: 4.4.4
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: bugs@sehe.nl


thread_results is allocated using scalar new, yet deleted with array delete[]

Version of libs (ubuntu package): libstdc++6-4.4-dev through libstdc++6-4.6-dev
Version of compiler: g++ (Ubuntu/Linaro 4.4.4-14ubuntu5) 4.4.5
Also with: g++ (Debian 4.5.2-8) 4.5.2

Snippets:
/usr/include/c++/4.4/parallel/par_loop.h:87
#   pragma omp single
{
        num_threads = omp_get_num_threads();
        thread_results = static_cast<Result*>(
                            ::operator new(num_threads * sizeof(Result)));
        constructed = new bool[num_threads];
}

but line 127:

    delete[] thread_results;

This is unbalanced, and leads to the expected valgrind errors. Attached is a
snippet (originally from
http://stackoverflow.com/questions/5769908/unexpected-segfault-with-gnu-parallelaccumulate)
that will segfault.

I witnessed the segfault went away when fixing the `delete[]` into `delete`.
However, I think it should be evaluated whether the optimized (uninitializing)
allocation of thread_results is safe to do (valgrind keeps reporting
uninitialized memory references even if the attached example doesn't segfault
anymore).

---- 

I'll attach the sources in 10 minutes due to time restriction and browser
flakiness

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #1 from Seth Heeren <bugs at sehe dot nl> 2011-04-24 11:51:17 UTC ---
Created attachment 24089
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24089
minimal example

Compiled with


g++ -g -O0 -fopenmp minimal.cpp  -o minimal -save-temps

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |WORKSFORME

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 12:11:29 UTC ---
This has been fixed a lot of time ago: 4_5-branch, 4_6-branch and mainline are
all fine.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2011.04.24 12:16:35
         Resolution|WORKSFORME                  |
     Ever Confirmed|0                           |1

--- Comment #3 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 12:16:35 UTC ---
Never mind, now I see.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |t.h.shorrock at gmail dot
                   |                            |com

--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 12:21:32 UTC ---
*** Bug 48751 has been marked as a duplicate of this bug. ***

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |singler at kit dot edu

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 12:26:17 UTC ---
Let's add Johannes in CC. Indeed, something is fishy here and yes I agree the
correct fix doesn't seem just using ::operator delete(__thread_results);

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #6 from Seth Heeren <bugs at sehe dot nl> 2011-04-24 12:54:15 UTC ---
That _is quick response. Thank you. I'll keep an eye on this one

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 21:51:51 UTC ---
I had a quick look to this code and something really bad is going on, like, eg,
memory deallocated before calling the destructor of the object constructed in
it via placement new. And much more.

The patchlet below, which I'd ask the submitters to test, gives me something
much more sane, wrt Valgrind too, but Jahannes should really have a look asap.

(Note the patch is versus mainline first, as usual, thus doesn't apply cleanly
as-is to 4.4 for various trivial reasons, like uglified names)

/////////////////

Index: par_loop.h
===================================================================
--- par_loop.h    (revision 172920)
+++ par_loop.h    (working copy)
@@ -91,8 +91,7 @@
     _ThreadIndex __iam = omp_get_thread_num();

     // Neutral element.
-    _Result* __reduct = static_cast<_Result*>
-      (::operator new(sizeof(_Result)));
+    _Result* __reduct;

     _DifferenceType
       __start = equally_split_point(__length, __num_threads, __iam),
@@ -100,7 +99,7 @@

     if (__start < __stop)
       {
-        new(__reduct) _Result(__f(__o, __begin + __start));
+        __reduct = new _Result(__f(__o, __begin + __start));
         ++__start;
         __constructed[__iam] = true;
       }
@@ -110,18 +109,26 @@
     for (; __start < __stop; ++__start)
       *__reduct = __r(*__reduct, __f(__o, __begin + __start));

-    __thread_results[__iam] = *__reduct;
+    if (__constructed[__iam])
+      {
+        ::new(&__thread_results[__iam]) _Result(*__reduct);
+        delete __reduct;
+      }
       } //parallel

       for (_ThreadIndex __i = 0; __i < __num_threads; ++__i)
     if (__constructed[__i])
-      __output = __r(__output, __thread_results[__i]);
+      {
+        __output = __r(__output, __thread_results[__i]);
+        (&__thread_results[__i])->~_Result();
+      }

       // Points to last element processed (needed as return value for
       // some algorithms like transform).
       __f._M_finish_iterator = __begin + __length;

-      delete[] __thread_results;
+      ::operator delete(__thread_results);
+
       delete[] __constructed;

       return __o;

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |paolo.carlini at oracle dot
                   |                            |com

--- Comment #8 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-24 22:13:24 UTC ---
Johannes, can you please also audit the other uses of operator new, placement
new, etc, and double check that:

  1- We are not assigning to an object before constructing.
  2- We destruct each object before deleting its memory.

Thanks!

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-26 15:19:12 UTC ---
Seth, Tom, if you get a chance to test the changes I propose in Comment 7
(suitably, trivially tweaked for 4.4.x), please let me know as soon as
possible.

If Johannes cannot provide feedback on this issue over the next few days I mean
to go ahead with my patch, likely for 4.6.x too, and work on a other similar
tweaks in the same spirit elsewhere in the parallel code (luckily we have only
an handful of operator new / operator delete pairs needing attention).

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[t.h.shorrock at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #10 from Tom <t.h.shorrock at gmail dot com> 2011-04-26 18:09:05 UTC ---
Hi Paulo,

Yes, this certainly fixes my segfault.

Valgrind complains a little - although I am not sure if this is important (I
am very new to the helgrind tool).  In case it is useful, I attach the
output I get,

So the line numbers are meaningful, I include my modified par_loop.h and my
test file.


Here is my g++ -v

Using built-in specs.
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu/Linaro
4.4.4-14ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.4 --enable-shared --enable-multiarch
--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --libdir=/usr/lib --enable-nls
--with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --disable-werror --with-arch-32=i686 --with-tune=generic
--enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=x86_64-linux-gnu
Thread model: posix
gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5)

running on Ubuntu 10-10


Many thanks for your assistance with this. My gratitude to the FSF grows
daily.

Tom



On 26 April 2011 16:20, paolo.carlini at oracle dot com <
gcc-bugzilla@gcc.gnu.org> wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750
>
> --- Comment #9 from Paolo Carlini <paolo.carlini at oracle dot com>
> 2011-04-26 15:19:12 UTC ---
> Seth, Tom, if you get a chance to test the changes I propose in Comment 7
> (suitably, trivially tweaked for 4.4.x), please let me know as soon as
> possible.
>
> If Johannes cannot provide feedback on this issue over the next few days I
> mean
> to go ahead with my patch, likely for 4.6.x too, and work on a other
> similar
> tweaks in the same spirit elsewhere in the parallel code (luckily we have
> only
> an handful of operator new / operator delete pairs needing attention).
>
> --
> Configure bugmail: http://gcc.gnu.org/bugzilla/userprefs.cgi?tab=email
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug.
>

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #11 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-26 18:38:26 UTC ---
(In reply to comment #10)
> Yes, this certainly fixes my segfault.

For me, it only fixes the segfault, also avoids all valgrind and glibc errors
messages at runtime and drastically improves the valgring report in terms of
memory leaks, to 0 definitely and 0 indirectly lost (try not ding 'delete
__reduct', as was effectively happening before the patch, for example, to see
what I mean). The report is still not perfect, indeed, there may be other leaks
somewhere else, I'm going to audit other bits of the parallel infrastructure as
I said. This is the valgrind report I get here on an i7-980X I have at hand:

==7206== LEAK SUMMARY:
==7206==    definitely lost: 0 bytes in 0 blocks
==7206==    indirectly lost: 0 bytes in 0 blocks
==7206==      possibly lost: 3,344 bytes in 11 blocks
==7206==    still reachable: 2,984 bytes in 3 blocks
==7206==         suppressed: 0 bytes in 0 blocks

> Valgrind complains a little - although I am not sure if this is important (I
> am very new to the helgrind tool).  In case it is useful, I attach the
> output I get,

Sure it would be useful. Note, in general, a few memory issues have been fixed
already in 4.5.x and 4.6.x, thus at some point, if you are serious about
parallel mode, updating GCC will be certainly recommended.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #12 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-26 18:40:17 UTC ---
Forgot: my numbers, etc, are all about the exaxt testcase in PR48751.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |ASSIGNED
         AssignedTo|unassigned at gcc dot       |paolo.carlini at oracle dot
                   |gnu.org                     |com
   Target Milestone|---                         |4.6.1

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #13 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-27 01:05:36 UTC ---
Created attachment 24108
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24108
Draft patch

This is my work ìn progress patch. I'm for example seeing very good to perfect
improvements in terms of valgrind reports for sort / stable_sort /
random_shuffle too, which, before the patch, when the ValueType has a non
trivial destructor leak a lot.

I'm going to the run the patch through the testsuite in parallel-mode and get
it closer to the final shape.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #15 from Seth Heeren <bugs at sehe dot nl> 2011-04-27 09:51:26 UTC ---
Probably redundant info, but the compiler used in my prior post is

sehe@sid:~$ g++-4.6 -v       
Using built-in specs.
COLLECT_GCC=g++-4.6
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i486-linux-gnu/4.6.1/lto-wrapper
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.6.0-2'
--with-bugurl=file:///usr/share/doc/gcc-4.6/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++,go --prefix=/usr
--program-suffix=-4.6 --enable-shared --enable-multiarch
--enable-linker-build-id --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.6 --libdir=/usr/lib --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--enable-plugin --enable-gold --enable-ld=default --with-plugin-ld
--enable-objc-gc --enable-targets=all --with-arch-32=i586 --with-tune=generic
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.6.1 20110329 (prerelease) (Debian 4.6.0-2)

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #14 from Seth Heeren <bugs at sehe dot nl> 2011-04-27 09:48:57 UTC ---
I just built a debian SID chroot and applied the diff to it's libstdc++6
(4.6.0-2), and tested your patch with the minimal.cpp from this bug report

patch -p1 < ~sehe/attachment.cgi?id=24108

    patching file parallel/multiway_merge.h
    patching file parallel/losertree.h
    patching file parallel/par_loop.h
    Hunk #1 succeeded at 91 with fuzz 1.
    patching file parallel/quicksort.h
    patching file parallel/random_shuffle.h
    patching file parallel/multiway_mergesort.h
    patching file parallel/partial_sum.h

g++-4.6 -g -O0 -fopenmp minimal.cpp  -o minimal -save-temps
valgrind --leak-check=full ./minimal

    ==5960== LEAK SUMMARY:
    ==5960==    definitely lost: 0 bytes in 0 blocks
    ==5960==    indirectly lost: 0 bytes in 0 blocks
    ==5960==      possibly lost: 456 bytes in 3 blocks
    ==5960==    still reachable: 1,748 bytes in 3 blocks
    ==5960==         suppressed: 0 bytes in 0 blocks

The allocation possibly lost are attributed to GOMP_parallel_start from
numeric:99). 

Helgrind gives quite the array of possible data races. I don't know whether I
need to worry about them (as I don't know what kind of thread primitives GOMP
uses internally and if helgrind supports them).

If you want I can attach precompiled sources + val/helgrind outputs

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[singler at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

singler@gcc.gnu.org <singler at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |singler at gcc dot gnu.org

--- Comment #16 from singler at gcc dot gnu.org <singler at gcc dot gnu.org> 2011-04-27 19:59:29 UTC ---
I have reviewed the patch, it looks mostly fine.  Thanks!
Only line 606 of losertree.h might not yet be fully consistent with line 597. 
I'm not sure all loser tree members are correctly constructed in the first
place.

We might have to add

        for (unsigned int __i = 0; __i < _M_k; ++__i)
          {
            ::new(&(_M_losers[__i]._M_key)) _Tp(__sentinel);
            _M_losers[__i]._M_source = -1;
          }

I will test that...

We have used these ::operator new/placement new construction to avoid calling
the default constructor, which might not be available for the ValueType. 
Interference with the actual parallelism should be minimal.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #17 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-04-27 20:23:25 UTC ---
Thanks Johannes. Indeed, I was still a little nervous about those bits of
losertree.h. If you can, please make sure that (even if it costs a bit of
performance):

  1- After memory allocation, the first time each objects is constructed, via
placement new, not assigned.
  2- All the following times are assigned, not constructed.
  3- All the object are destructed, once, by calling explicitly the destructor,
in the destructor of _LoserTree* class, before deallocating the memory via
operator delete. Careful not trying to destruct objects never constructed in
the first place.

In general, I recommend preparing a tiny snippet code exercising the parallel
code at issue and running it under valgrind (doing that yesterday for the
elements of a vector<string>, for sort, stable_sort, etc, turned out to be
rather "interesting" ;)

Please, keep me up to date, we want to resolve this for 4.6.1, I think.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.1                       |---

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #18 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2011-05-03 14:20:49 UTC ---
Author: paolo
Date: Tue May  3 14:20:45 2011
New Revision: 173309

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173309
Log:
2011-05-03  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/48750
    * include/parallel/multiway_merge.h: Run _ValueType destructors.
    * include/parallel/multiway_mergesort.h: Likewise.
    * include/parallel/quicksort.h: Likewise.
    * include/parallel/random_shuffle.h: Likewise.
    * include/parallel/partial_sum.h: Likewise.
    * include/parallel/losertree.h: Run destructors; minor tweaks.
    * include/parallel/par_loop.h: Run destructors, fix memory
    allocations and deallocations.
    * testsuite/26_numerics/accumulate/48750.cc: New.

    * testsuite/ext/profile/mutex_extensions_neg.cc: Do not run in
    parallel-mode to avoid spurious multiple errors.


Added:
    trunk/libstdc++-v3/testsuite/26_numerics/accumulate/48750.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/parallel/losertree.h
    trunk/libstdc++-v3/include/parallel/multiway_merge.h
    trunk/libstdc++-v3/include/parallel/multiway_mergesort.h
    trunk/libstdc++-v3/include/parallel/par_loop.h
    trunk/libstdc++-v3/include/parallel/partial_sum.h
    trunk/libstdc++-v3/include/parallel/quicksort.h
    trunk/libstdc++-v3/include/parallel/random_shuffle.h
    trunk/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[bugs at sehe dot nl]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #19 from Seth Heeren <bugs at sehe dot nl> 2011-05-03 15:47:28 UTC ---
Cheers!

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.6.1
           Severity|major                       |normal

--- Comment #21 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-05-03 17:55:39 UTC ---
Fixed for 4.6.1.

[Bug libstdc++/48750] for_each_template_random_access_ed has unbalanced new/delete[]

[paolo at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48750

--- Comment #20 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2011-05-03 17:54:41 UTC ---
Author: paolo
Date: Tue May  3 17:54:35 2011
New Revision: 173335

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=173335
Log:
2011-05-03  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/48750
    * include/parallel/multiway_merge.h: Run _ValueType destructors.
    * include/parallel/multiway_mergesort.h: Likewise.
    * include/parallel/quicksort.h: Likewise.
    * include/parallel/random_shuffle.h: Likewise.
    * include/parallel/partial_sum.h: Likewise.
    * include/parallel/losertree.h: Run destructors; minor tweaks.
    * include/parallel/par_loop.h: Run destructors, fix memory
    allocations and deallocations.
    * testsuite/26_numerics/accumulate/48750.cc: New.

    * testsuite/ext/profile/mutex_extensions_neg.cc: Do not run in
    parallel-mode to avoid spurious multiple errors.

Added:
   
branches/gcc-4_6-branch/libstdc++-v3/testsuite/26_numerics/accumulate/48750.cc
Modified:
    branches/gcc-4_6-branch/libstdc++-v3/ChangeLog
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/losertree.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/multiway_merge.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/multiway_mergesort.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/par_loop.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/partial_sum.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/quicksort.h
    branches/gcc-4_6-branch/libstdc++-v3/include/parallel/random_shuffle.h
   
branches/gcc-4_6-branch/libstdc++-v3/testsuite/ext/profile/mutex_extensions_neg.cc