[Bug c/37102] New: possible integer codegen bug

[Bug c/37102] New: possible integer codegen bug

[regehr at cs dot utah dot edu]

This is for svn 139046 on Ubuntu Hardy.

regehr@john-home:~/volatile/tmp0$ current-gcc -O -Wall -fwrapv small.c -o small
regehr@john-home:~/volatile/tmp0$ ./small
5
regehr@john-home:~/volatile/tmp0$ current-gcc -O3 -Wall -fwrapv small.c -o
small
regehr@john-home:~/volatile/tmp0$ ./small
0
regehr@john-home:~/volatile/tmp0$ current-gcc -v
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../configure --program-prefix=current-
--enable-languages=c,c++ --prefix=/home/regehr
Thread model: posix
gcc version 4.4.0 20080813 (experimental) (GCC) 
regehr@john-home:~/volatile/tmp0$ cat small.c

#include <stdio.h>

unsigned int g_24;
unsigned int g_37 = 1;
unsigned char g_225;

int main (void)
{
  int l_289;
  for (l_289 = 1; l_289 < 5; l_289 += 1) {
    if (g_225) {
      g_24 = g_37;
    }
  }
  g_24 = g_37;
  unsigned short context = g_24 << 1;
  do {
    if (context)
      context = (context << 1) ^ 1;
  } while (0);
  printf ("%d\n", (int)context);
  return 0;
}


-- 
           Summary: possible integer codegen bug
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: regehr at cs dot utah dot edu
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2008-08-13 09:53 -------
-fno-unswitch-loops fixes the original testcase but not the following which
only fails _with_ -O3 -fno-unswitch-loops.

extern void abort (void);

unsigned int g_24;
unsigned int g_37 = 1;
unsigned int g_225 = 0;

int main ()
{
  unsigned int l_289;
  for (l_289 = 1; l_289 < 5; l_289 += 1) {
      if (g_225) {
          g_24 = g_37;
      }
  }
  g_24 = g_37;
  unsigned int context = g_24 << 1;
  do {
      if (context)
        context = (context << 1) ^ 1;
  } while (0);
  if (context != 5)
    abort ();
  return 0;
}


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
          Component|c                           |tree-optimization
     Ever Confirmed|0                           |1
  GCC build triplet|i686-pc-linux-gnu           |
   GCC host triplet|i686-pc-linux-gnu           |
 GCC target triplet|i686-pc-linux-gnu           |
           Keywords|                            |wrong-code
      Known to fail|                            |4.3.1 4.4.0
      Known to work|                            |4.2.4
   Last reconfirmed|0000-00-00 00:00:00         |2008-08-13 09:53:31
               date|                            |
            Summary|possible integer codegen bug|[4.3/4.4 Regression]
                   |                            |possible integer codegen bug
   Target Milestone|---                         |4.3.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2008-08-13 09:54 -------
Testcase failing with -O3 but not with -O3 -fno-unswitch-loops:

extern void abort (void);

unsigned int g_24;
unsigned int g_37 = 1;
unsigned int g_225 = 0;

void __attribute__((noinline)) foo (int x)
{
  if (x != 5)
    abort ();
}

int main ()
{
  unsigned int l_289;
  for (l_289 = 1; l_289 < 5; l_289 += 1) {
      if (g_225) {
          g_24 = g_37;
      }
  }
  g_24 = g_37;
  unsigned int context = g_24 << 1;
  do {
      if (context)
        context = (context << 1) ^ 1;
  } while (0);
  foo (context);
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[jakub at gcc dot gnu dot org]

------- Comment #3 from jakub at gcc dot gnu dot org  2008-08-14 10:02 -------
Somewhat shorter:
extern void abort (void);

unsigned int a, b = 1, c;

void __attribute__ ((noinline))
foo (int x)
{
  if (x != 5)
    abort ();
}

int
main ()
{
  unsigned int d, e;
  for (d = 1; d < 5; d++)
    if (c)
      a = b;
  a = b;
  e = a << 1;
  if (e)
    e = (e << 1) ^ 1;
  foo (e);
  return 0;
}

At *.tailc looks sane to me.
<bb 2>:
  pretmp.35_15 = c;
  b.1_5 = b;
  a_lsm.48_4 = a;
  if (pretmp.35_15 != 0)
    goto <bb 3>;
  else
    goto <bb 4>;

<bb 3>:

<bb 4>:
  # a_lsm.48_28 = PHI <b.1_5(3), a_lsm.48_4(2)>
  a = b.1_5;
  e_9 = b.1_5 << 1;
  if (e_9 != 0)
    goto <bb 5>;
  else
    goto <bb 6>;
so a_lsm.48_28 is either b or a, depending on whether c != 0 or not, and a = b.
Then copyrename4 decides to replace a = b.1_5; with a = a_lsm_48_5; and at
*.uncprop we have:
<bb 2>:
  pretmp.35_15 = c;
  a_lsm.48_5 = b;
  a_lsm.48_4 = a;
  if (pretmp.35_15 != 0)
    goto <bb 3>;
  else
    goto <bb 4>;

<bb 3>:

<bb 4>:
  # a_lsm.48_28 = PHI <a_lsm.48_5(3), a_lsm.48_4(2)>
  a = a_lsm.48_5;
  e_9 = a_lsm.48_5 << 1;
  if (e_9 != 0)
    goto <bb 5>;
  else
    goto <bb 6>;
which looks correct too.  But *.optimized is already wrong:
<bb 2>:
  a_lsm.49 = b;
  a_lsm.48 = a;
  if (c != 0)
    goto <bb 3>;
  else
    goto <bb 7>;

<bb 7>:
  a_lsm.49 = a_lsm.48;
  goto <bb 4>;

<bb 3>:

<bb 4>:
  a = a_lsm.49;
  e = a_lsm.49 << 1;
  if (e != 0)
    goto <bb 5>;
  else
    goto <bb 8>;
While in *.uncprop a was set unconditionally to b, now it is sometimes b and
sometimes a.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[jsm28 at gcc dot gnu dot org]

-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[cnstar9988 at gmail dot com]

------- Comment #4 from cnstar9988 at gmail dot com  2008-08-26 13:38 -------
gcc 4.3.2 20080826 failed.

----------------------------
#include <stdio.h>

unsigned int g_24;
unsigned int g_37 = 1;
unsigned char g_225;

int main (void)
{
  int l_289;
  for (l_289 = 1; l_289 < 5; l_289 += 1) {
    if (g_225) {
      g_24 = g_37;
    }
  }
  g_24 = g_37;
  unsigned short context = g_24 << 1;
  do {
    if (context)
      context = (context << 1) ^ 1;
  } while (0);
  printf ("%d\n", (int)context);
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[jsm28 at gcc dot gnu dot org]

------- Comment #5 from jsm28 at gcc dot gnu dot org  2008-08-27 22:05 -------
4.3.2 is released, changing milestones to 4.3.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.2                       |4.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] possible integer codegen bug

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2008-08-28 14:48 -------
It looks like that we correctly track liveliness by

Live on entry to BB2 :

Live on entry to BB3 : a_lsm.27_5

Live on entry to BB4 : a_lsm.27_5

Live on entry to BB5 :

Live on entry to BB6 :

for

  # BLOCK 2 freq:2000
  # PRED: ENTRY [100.0%]  (fallthru,exec)
  c.0_4 = c;
  a_lsm.27_5 = b;
  a_lsm.27_1 = a;
  if (c.0_4 != 0)
    goto <bb 3>;
  else
    goto <bb 4>;
  # SUCC: 4 [50.0%]  (false,exec) 3 [50.0%]  (true,exec)

  # BLOCK 3 freq:1000
  # PRED: 2 [50.0%]  (true,exec)
  # SUCC: 4 [100.0%]  (fallthru,exec)

  # BLOCK 4 freq:2000
  # PRED: 3 [100.0%]  (fallthru,exec) 2 [50.0%]  (false,exec)
  # a_lsm.27_29 = PHI <a_lsm.27_5(3), a_lsm.27_1(2)>
  a = a_lsm.27_5;
  e_9 = a_lsm.27_5 << 1;
  if (e_9 != 0)
    goto <bb 5>;
  else
    goto <bb 6>;
  # SUCC: 5 [54.0%]  (true,exec) 6 [46.0%]  (false,exec)


and based on this create the conflict graph.  But we still (blindly)
generate copies for the (dead) PHI node in BB4 which causes conflicts
that we didn't see.

So, why exactly do we generate copies for a PHI node which result is
not live-in in its BB?  Andrew - you are probably most familiar with
the out-of-SSA code, can you have a look here?  (the dead PHI node is
caused by the last DSE pass which removes the last use of it and there
is no other DCE pass to clean that up).

Jakubs testcase from comment #3 at -O3.

My humble "fix" for this would be to exchange 118.cddce with 120.dse which
should hide this problem.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amacleod at redhat dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2008-09-04 14:53 -------
As on the trunk we are now feeding out-of-SSA with random dead statements
at -O0 we should look into this.  Or schedule a DCE pass before it if it
cannot cope with dead statements.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |blocker
           Priority|P2                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #8 from amacleod at redhat dot com  2008-09-04 16:09 -------
out of ssa generally expects that there is no dead code. 

I think the original logic was that you never want to generate code for dead
statements, so DCE would be run just before out of ssa.

It assumes any conflicts caused by any copies which will be inserted are
already covered in the conflict graph.  In this particular case, if the PHI
results was live for even a statement or two, it would conflict with the use of
a_lsm.27_5 in the next statement, and then the coalesce would happen with
a_lsm.27_1 instead.  We'd still get the dead copy, but the code would work
fine.

That's a reasonable example of why we don't want to feed dead code into
outofssa. Figuring out which PHI parameter is TRULY available would be a tricky
proposition to catch this case. And its a waste.

So we either run dead code just before out of ssa, or take PHI's with no uses
and discard them at the same time we discard virtual PHIs (this would be
trivial). I wonder if we might eventually find a similar circumstance with a
dead PHI cycle that would not be easy to detect without the same logic as a DCE
tho.

I'd say a DCE pass is generally a better approach, and should be documented as
a requirement, or even wired in.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2008-09-04 16:17 -------
Thanks for the explanation, for the branch I would recommend an extra DCE
pass right before pass_del_ssa.  On the trunk we need to make sure to run
this at -O0 as well.  Note that the simple DCE can leave dead statements
around, only control-dependent DCE will make sure to not retain any
DCE opportunities.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #10 from amacleod at redhat dot com  2008-09-04 16:51 -------
As long as it removes any dead PHIs, it would be sufficient. Other types of
dead statements don't have 'unexpected' side effects across basic block
boundaries, and should be handled fine. Other than being a waste of effort of
course :-)

A little further thinking leads me to think dead PHI cycles could not produce
this problem. The PHI results would get conflicts since they are live out their
basic blocks. It the lack of any use in this case that is the problem.

But removing a PHI with no uses can easily have ripple effects in that it may
have been the only use of some other PHI, etc, etc.  So we're back to DCE type
work anyway.   


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[lthode at mail dot unomaha dot edu]

------- Comment #11 from lthode at mail dot unomaha dot edu  2008-09-15 01:03 -------
(In reply to comment #9)
> Thanks for the explanation, for the branch I would recommend an extra DCE
> pass right before pass_del_ssa.  On the trunk we need to make sure to run
> this at -O0 as well.  Note that the simple DCE can leave dead statements
> around, only control-dependent DCE will make sure to not retain any
> DCE opportunities.
> 

Well, I tried just that (running CD-DCE right before Out-of-SSA independent of
optimization level) on the trunk, and 16 Fortran testcases blow up (with an ICE
in Out-of-SSA) at -O0 due to it.  However, turning optimization on makes them
compile again, so running DCE at -O0 isn't such a great idea.  On the other
hand, this should be easy enough to fix on the branch, as we can just run the
pass if optimization is enabled.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2008-09-17 14:25 -------
Ok, so I think we should be fine if we ignore PHI nodes with zero-use results
during building the elimination graph - chained unused PHIs will have lifeness
computed for all but the PHI node with the zero-use result.

So, on the 4.3 branch the following fixes the failure for me:

Index: tree-outof-ssa.c
===================================================================
*** tree-outof-ssa.c    (revision 140417)
--- tree-outof-ssa.c    (working copy)
*************** eliminate_build (elim_graph g, basic_blo
*** 321,326 ****
--- 321,329 ----

    for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi))
      {
+       if (has_zero_uses (PHI_RESULT (phi)))
+       continue;
+ 
        T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi));

        /* Ignore results which are not in partitions.  */


I am now giving this testing.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #13 from amacleod at redhat dot com  2008-09-17 14:34 -------
I was in the middle of updating this PR and taking possesion :-)

Upon further reflection, I don't think it is acceptable for out-of-ssa to
generate incorrect code simply because an optimization wasn't run before it.

So, there are 2 basic choices. ONnis as you state, only there is an additional
bit required during the rewrite verification.  

The other option is a very mini dead phi removal done at the same time as
virtual phis are eliminated. its only a few lines of code and simple removes
PHIs with no uses, and takes care of the ripple effect as well. I have a patch
for it as well, its just not completely tested yet.

I'll attach both in a minute, I just wanted you to know I was looking at it :-)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #14 from rguenth at gcc dot gnu dot org  2008-09-17 14:38 -------
Hm, it doesn't work - bootstrap fails as gengtype segfaults.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #15 from amacleod at redhat dot com  2008-09-17 14:39 -------
Created an attachment (id=16343)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16343&action=view)
potential patch 1

This is the first option which simply doesn't add the result of a PHI with no
uses to the partition map.  It passes bootstrap and all tests on
x86_64-unknown-linux-gnu with no regressions.


-- 

amacleod at redhat dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |amacleod at redhat dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #16 from amacleod at redhat dot com  2008-09-17 14:48 -------
Created an attachment (id=16345)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16345&action=view)
Potential patch #2

This is the other option, eliminate dead PHIs.  compiling all of GCC .c files
at -O3, it finds a total of 12 instances of dead phis, and 3 of those were
"extra" ones made dead by elimination of the original dead PHI.


This patch has not yet been bootstrapped and fully tested, its ongoing now.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #17 from amacleod at redhat dot com  2008-09-17 21:55 -------
Created an attachment (id=16348)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16348&action=view)
Patch submitted

Doh. The last patch for the dead code removal had a disabling check in it that
I was using for some testing, so it didn't actually do anything :-P

This is the correct patch which I will be checking in. It has been bootstrapped
and passed all tests with no regressions on x86_64-unknown-linux-gnu. 


-- 

amacleod at redhat dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #16343|0                           |1
        is obsolete|                            |
  Attachment #16345|0                           |1
        is obsolete|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[amacleod at gcc dot gnu dot org]

------- Comment #18 from amacleod at redhat dot com  2008-09-18 14:00 -------
Subject: Bug 37102

Author: amacleod
Date: Thu Sep 18 13:58:55 2008
New Revision: 140455

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=140455
Log:
fix PR 37102 by having out of ssa remove dead PHI nodes.


Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr37102.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-outof-ssa.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[amacleod at redhat dot com]

------- Comment #19 from amacleod at redhat dot com  2008-09-18 20:04 -------
The patch should be fine for 4.3, but I'll give it a few days in mainline and
see if anything shows up on any overnight or weekly runs


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[cnstar9988 at gmail dot com]

------- Comment #20 from cnstar9988 at gmail dot com  2008-09-27 11:32 -------
ping...
The bug is not fixed in 4.3-branch.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[cnstar9988 at gmail dot com]

------- Comment #21 from cnstar9988 at gmail dot com  2008-10-10 00:56 -------
Does this patch works well on 4.3?
Thanks!


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[lthode at mail dot unomaha dot edu]

------- Comment #22 from lthode at mail dot unomaha dot edu  2008-10-12 19:57 -------
amacleod: ping?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[amacleod at gcc dot gnu dot org]

------- Comment #23 from amacleod at redhat dot com  2008-10-17 17:37 -------
Subject: Bug 37102

Author: amacleod
Date: Fri Oct 17 17:35:58 2008
New Revision: 141195

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=141195
Log:
fix PR tree-optimization/37102

2008-10-17  Andrew MacLeod  <amacleod@redhat.com>

        PR tree-optimization/37102
        * tree-outof-ssa.c (remove_gimple_phi_args): Remove all the PHI args  
        from a node. Check to see if another PHI is dead.
        (eliminate_useless_phis): Rename from eliminate_virtual_phis and remove
        real PHIs which have no uses.
        (rewrite_out_of_ssa): Call eliminate_useless_phis.

2008-10-17  Andrew MacLeod  <amacleod@redhat.com>

        PR tree-optimization/37102
        * gcc.c-torture/execute/pr37102.c: New Test.


Added:
    branches/gcc-4_3-branch/gcc/testsuite/gcc.c-torture/execute/pr37102.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog
    branches/gcc-4_3-branch/gcc/tree-outof-ssa.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102

[Bug tree-optimization/37102] [4.3 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #24 from rguenth at gcc dot gnu dot org  2008-10-18 11:17 -------
Fixed then.  Thanks.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|4.2.4 4.4.0                 |4.2.4 4.3.3 4.4.0
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102