[Bug rtl-optimization/34171] New: [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[Bug rtl-optimization/34171] New: [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

With current trunk on Alpha with -O3:

(sid)170:tbm@vorpal: ~] /usr/lib/gcc-snapshot/bin/gcc -O3
enlightenment-handlers.c
enlightenment-handlers.c: In function 'doSignalsSetup':
enlightenment-handlers.c:24: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.


-- 
           Summary: [4.3 Regression] Segfault in df_chain_remove_problem
                    with -O3 on alpha
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: tbm at cyrius dot com
GCC target triplet: alpha-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #1 from tbm at cyrius dot com  2007-11-21 09:19 -------
Program received signal SIGSEGV, Segmentation fault.
df_chain_remove_problem () at gcc/df-problems.c:1948
1948            for (use_rec = df_get_artificial_uses (bb->index); *use_rec;
use_rec++)
(gdb) where
#0  df_chain_remove_problem () at gcc/df-problems.c:1948
#1  0x00000001201466fc in df_chain_fully_remove_problem ()
    at gcc/df-problems.c:1981
#2  0x000000012013e3e8 in df_finish_pass (verify=0 '\0') at gcc/df-core.c:663
#3  0x00000001202e3a78 in execute_todo (flags=132097) at gcc/passes.c:1015
#4  0x00000001202e4230 in execute_one_pass (pass=0x1208c5e28)
    at gcc/passes.c:1140
#5  0x00000001202e4488 in execute_pass_list (pass=0x1208c5e28)
    at gcc/passes.c:1171
#6  0x00000001202e449c in execute_pass_list (pass=0x1208c25d8)
    at gcc/passes.c:1172
#7  0x00000001203fc414 in tree_rest_of_compilation (fndecl=0x200004a6c30)
    at gcc/tree-optimize.c:404
#8  0x00000001205f77c8 in cgraph_expand_function (node=0x200003e6500)
    at gcc/cgraphunit.c:1151
#9  0x00000001205fab20 in cgraph_optimize () at gcc/cgraphunit.c:1214
#10 0x000000012001ad58 in c_write_global_declarations () at gcc/c-decl.c:8081
#11 0x0000000120381888 in toplev_main (argc=<value optimized out>, argv=<value
    optimized out>) at gcc/toplev.c:1055
#12 0x00000001200afa58 in main (argc=2550688, argv=0x0) at gcc/main.c:35
(gdb)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #3 from tbm at cyrius dot com  2007-11-21 09:20 -------
/* Testcase by Martin Michlmayr <tbm@cyrius.com> */

extern char coredump;
extern void sigemptyset (char *);
struct sigaction
{
  char sa_mask;
};
void doSignalsSetup (void)
{
  static const int signals[] = {
    1, 2, 3, 4, 6, 8, 11, 13, 14, 15, 30 , 31
  };
  unsigned int i, sig;
  struct sigaction sa;
  for (i = 0; i < sizeof (signals) / sizeof (int); i++)
    {
      sig = signals[i];
      if (coredump &&
          (sig == 4 || sig == 8 || sig == 11 || sig == 10))
        continue;
      sigemptyset (&sa.sa_mask);
    }
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #2 from tbm at cyrius dot com  2007-11-21 09:19 -------
Created an attachment (id=14588)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14588&action=view)
preprocessed source


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[bonzini at gnu dot org]

------- Comment #4 from bonzini at gnu dot org  2007-11-21 09:47 -------
Created an attachment (id=14589)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14589&action=view)
attempt

Can you try this patch?  I don't have the resources now to build a cross and
test it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #5 from tbm at cyrius dot com  2007-11-21 10:56 -------
(In reply to comment #4)
> Created an attachment (id=14589)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14589&action=view) [edit]
> attempt
> 
> Can you try this patch?  I don't have the resources now to build a cross and
> test it.

Now I'm getting:

Program received signal SIGSEGV, Segmentation fault.
0x00000001201466d0 in df_chain_remove_problem () at
/home/tbm/scratch/gcc/gcc/df-problems.c:1941
1941          struct df_ref **def_rec = df_get_artificial_defs (bb->index);
(gdb) where
#0  0x00000001201466d0 in df_chain_remove_problem () at
/home/tbm/scratch/gcc/gcc/df-problems.c:1941
#1  0x00000001201469e8 in df_chain_fully_remove_problem ()
    at /home/tbm/scratch/gcc/gcc/df-problems.c:1982


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[paolo dot bonzini at lu dot unisi dot ch]

------- Comment #6 from paolo dot bonzini at lu dot unisi dot ch  2007-11-21 12:51 -------
Subject: Re:  [4.3 Regression] Segfault in df_chain_remove_problem
 with -O3 on alpha

So it means the basic block has been deleted.

I want to see what happens if I consolidate all the 
out_of_date_transfer_functions bitmaps into one.  Seongbae, do you 
remember experimenting with anything like that?

Paolo


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #7 from spark at gcc dot gnu dot org  2007-11-21 16:22 -------
(In reply to comment #6)
> Subject: Re:  [4.3 Regression] Segfault in df_chain_remove_problem
>  with -O3 on alpha
> 
> So it means the basic block has been deleted.
> 
> I want to see what happens if I consolidate all the 
> out_of_date_transfer_functions bitmaps into one.  Seongbae, do you 
> remember experimenting with anything like that?
> 
> Paolo

Not really. 
I agree that it's most likely a bb being deleted though.
I guess somebody will have to trace through using a debugger 
I'll try to build a cross to alpha and see if I can reproduce the problem
today.


-- 

spark at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |spark at gcc dot gnu dot org
                   |dot org                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[steven at gcc dot gnu dot org]

------- Comment #8 from steven at gcc dot gnu dot org  2007-11-21 17:47 -------
Martin, can you go up to frame #4, and do "print *pass" in gdb? Thanks.


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-11-21 17:47:04
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #9 from tbm at cyrius dot com  2007-11-21 18:11 -------
(In reply to comment #8)
> Martin, can you go up to frame #4, and do "print *pass" in gdb? Thanks.

You mean in execute_one_pass, right?

Breakpoint 4, execute_one_pass (pass=0x1208c51b8) at gcc/passes.c:1065
1065      current_pass = pass;
(gdb) print *pass
$1 = {name = 0x1207c2e7e "useless", gate = 0,
  execute = 0x1203a57a0 <remove_useless_stmts>,
  sub = 0x0, next = 0x120896890, static_pass_number = 12,
  tv_id = 0, properties_required = 1,
  properties_provided = 0, properties_destroyed = 0,
  todo_flags_start = 589824,
  todo_flags_finish = 1, letter = 0 '\0'}
(gdb)
(gdb) c
Continuing.

Breakpoint 3, execute_one_pass (pass=0x1208c51b8) at gcc/passes.c:1140
1140      execute_todo (todo_after | pass->todo_flags_finish);
(gdb) print *pass
$2 = {name = 0x1207c2e7e "useless", gate = 0,
  execute = 0x1203a57a0 <remove_useless_stmts>,
  sub = 0x0, next = 0x120896890, static_pass_number = 12,
  tv_id = 0, properties_required = 1,
  properties_provided = 0, properties_destroyed = 0,
  todo_flags_start = 589824,
  todo_flags_finish = 1, letter = 0 '\0'}
(gdb)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[steven at gcc dot gnu dot org]

------- Comment #10 from steven at gcc dot gnu dot org  2007-11-21 20:02 -------
That is useless information.  You have a breakpoint on execute_one_pass, which
executes the pass list.

Look at *pass _at the point of the ICE_.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[tbm at cyrius dot com]

------- Comment #11 from tbm at cyrius dot com  2007-11-21 20:23 -------
(In reply to comment #10)
> That is useless information.  You have a breakpoint on execute_one_pass, which
> executes the pass list.

I thought you said frame 4 and that was execute_one_pass.  Anyway, Seongbae
Park found the problem in the meantime so I guess he'll add more info soon.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #12 from spark at gcc dot gnu dot org  2007-11-21 20:40 -------
At the end of fwprop2 pass in fwprop_done(), we call cleanup_cfg()
and it merges a few blocks, making some bb disappear (in this particular case,
bb index 25), which clears the bit in df_chain->out_of_date_transfer_functions.
Then, somehow, some of the insns originating from 25 has their bb numbers not
reset, and later those insns get the new bb numbers assigned, at which point we
call df_insn_change_bb(), which sets the bit for the deleted block on
out_of_date_transfer_functions map.
Then after fwprop, TODO runs df_finish_pass and we bomb.

I'm working on a fix.


-- 

spark at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-11-21 17:47:04         |2007-11-21 20:40:45
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #13 from spark at gcc dot gnu dot org  2007-11-21 22:08 -------
The following patch seems to fix the problem:

diff -r fad6feb87420 gcc/cfgrtl.c
--- a/gcc/cfgrtl.c      Wed Nov 21 00:17:50 2007 +0000
+++ b/gcc/cfgrtl.c      Wed Nov 21 14:07:15 2007 -0800
@@ -2629,6 +2629,7 @@ cfg_layout_merge_blocks (basic_block a,
   /* In the case basic blocks are not adjacent, move them around.  */
   if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
     {
+      rtx insn;
       rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));

       emit_insn_after_noloc (first, BB_END (a), a);
@@ -2637,7 +2638,15 @@ cfg_layout_merge_blocks (basic_block a,
        first = NEXT_INSN (first);
       gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
       BB_HEAD (b) = NULL;
+      insn = NEXT_INSN (first);
       delete_insn (first);
+
+      for (; insn != NEXT_INSN (BB_END (b));
+          insn = NEXT_INSN (insn))
+       {
+         set_block_for_insn (insn, a);
+         df_insn_change_bb (insn);
+       }
     }
   /* Otherwise just re-associate the instructions.  */
   else


I'm going to stare at the surrounding code a bit more 
to convince myself, and will do some testing.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[steven at gcc dot gnu dot org]

------- Comment #14 from steven at gcc dot gnu dot org  2007-11-21 22:30 -------
The patch is semi-wrong.  The call to emit_insn_after_noloc() should already
set the proper BLOCK_FOR_INSN for every insn.  Only doing the
df_insn_change_bb() should be sufficient.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #15 from spark at gcc dot gnu dot org  2007-11-21 22:43 -------
(In reply to comment #14)
> The patch is semi-wrong.  The call to emit_insn_after_noloc() should already
> set the proper BLOCK_FOR_INSN for every insn.  Only doing the
> df_insn_change_bb() should be sufficient.

Thanks Steven. Something like:

diff -r fad6feb87420 gcc/cfgrtl.c
--- a/gcc/cfgrtl.c      Wed Nov 21 00:17:50 2007 +0000
+++ b/gcc/cfgrtl.c      Wed Nov 21 14:40:43 2007 -0800
@@ -2629,6 +2629,7 @@ cfg_layout_merge_blocks (basic_block a,
   /* In the case basic blocks are not adjacent, move them around.  */
   if (NEXT_INSN (BB_END (a)) != BB_HEAD (b))
     {
+      rtx insn;
       rtx first = unlink_insn_chain (BB_HEAD (b), BB_END (b));

       emit_insn_after_noloc (first, BB_END (a), a);
@@ -2637,6 +2638,14 @@ cfg_layout_merge_blocks (basic_block a,
        first = NEXT_INSN (first);
       gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
       BB_HEAD (b) = NULL;
+
+      /* emit_insn_after_noloc doesn't call df_insn_change_bb.
+         We need to explicitly call df_insn_change_bb here. */
+      for (insn = NEXT_INSN (first);
+          insn != NEXT_INSN (BB_END (b));
+          insn = NEXT_INSN (insn))
+       df_insn_change_bb (insn);
+
       delete_insn (first);
     }
   /* Otherwise just re-associate the instructions.  */


I see bunch of similar loops throughout cfgrtl.c.
I'll see if I should refactor those loops into separate functions 
(one with set_block_for_insn and one without).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #16 from spark at gcc dot gnu dot org  2007-11-22 00:30 -------
I'm bootstrapping the following patch. This includes some slight refactoring of
set_block_for_insn/df_insn_change_bb loops within cfgrtl.c.
It's mostly cosmetic change on top of the patch on comment #15.

diff -r fad6feb87420 gcc/cfgrtl.c
--- a/gcc/cfgrtl.c      Wed Nov 21 00:17:50 2007 +0000
+++ b/gcc/cfgrtl.c      Wed Nov 21 23:48:55 2007 +0000
@@ -465,23 +465,48 @@ emit_insn_at_entry (rtx insn)
   commit_edge_insertions ();
 }

-/* Update insns block within BB.  */
+/* Update BLOCK_FOR_INSN of insns between BEGIN and END
+   including BEGIN but not END, and notify df of the change.
+   Note that NEXT_INSN (END) has to have a valid value
+   (either NULL or a pointer to a valid insn). */
+
+static void
+update_bb_for_insns (rtx begin, rtx end, basic_block bb)
+{
+  rtx insn;
+
+  for (insn = begin; insn != end; insn = NEXT_INSN (insn))
+    {
+      if (!BARRIER_P (insn))
+       {
+         set_block_for_insn (insn, bb);
+         df_insn_change_bb (insn);
+       }
+    }
+}
+
+/* Call df_insn_change_bb for insns between BEGIN and END
+   including BEGIN but not END.
+   Note that NEXT_INSN (END) has to have a valid value
+   (either NULL or a pointer to a valid insn). */
+
+static void
+notify_bb_change_for_insns (rtx begin, rtx end)
+{
+  rtx insn;
+
+  for (insn = begin; insn != end; insn = NEXT_INSN (insn))
+    if (!BARRIER_P (insn))
+      df_insn_change_bb (insn);
+}
+
+/* Update BLOCK_FOR_INSN of insns in BB to BB,
+   and notify df of the change.  */

 void
 update_bb_for_insn (basic_block bb)
 {
-  rtx insn;
-
-  for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
-    {
-      if (!BARRIER_P (insn))
-       {
-         set_block_for_insn (insn, bb);
-         df_insn_change_bb (insn);
-       }
-      if (insn == BB_END (bb))
-       break;
-    }
+  update_bb_for_insns (BB_HEAD (bb), NEXT_INSN (BB_END (bb)), bb);
 }


 /* Return the INSN immediately following the NOTE_INSN_BASIC_BLOCK
@@ -629,16 +654,7 @@ rtl_merge_blocks (basic_block a, basic_b
   /* Reassociate the insns of B with A.  */
   if (!b_empty)
     {
-      rtx x;
-
-      for (x = a_end; x != b_end; x = NEXT_INSN (x))
-       {
-         set_block_for_insn (x, a);
-         df_insn_change_bb (x);
-       }
-
-      set_block_for_insn (b_end, a);
-      df_insn_change_bb (b_end);
+      update_bb_for_insns (a_end, NEXT_INSN (b_end), a);

       a_end = b_end;
     }
@@ -843,14 +859,9 @@ try_redirect_by_replacing_jump (edge e,
                 which originally were or were created before jump table are
                 inside the basic block.  */
              rtx new_insn = BB_END (src);
-             rtx tmp;
-
-             for (tmp = NEXT_INSN (BB_END (src)); tmp != barrier;
-                  tmp = NEXT_INSN (tmp))
-               {
-                 set_block_for_insn (tmp, src);
-                 df_insn_change_bb (tmp);
-               }
+
+             update_bb_for_insns (NEXT_INSN (BB_END (src)),
+                                  barrier, src);

              NEXT_INSN (PREV_INSN (new_insn)) = NEXT_INSN (new_insn);
              PREV_INSN (NEXT_INSN (new_insn)) = PREV_INSN (new_insn);
@@ -2637,6 +2648,12 @@ cfg_layout_merge_blocks (basic_block a,
        first = NEXT_INSN (first);
       gcc_assert (NOTE_INSN_BASIC_BLOCK_P (first));
       BB_HEAD (b) = NULL;
+
+      /* emit_insn_after_noloc doesn't call df_insn_change_bb.
+         We need to explicitly notify. */
+      notify_bb_change_for_insns (NEXT_INSN (first),
+                                 NEXT_INSN (BB_END (b)));
+
       delete_insn (first);
     }
   /* Otherwise just re-associate the instructions.  */
@@ -2644,13 +2661,8 @@ cfg_layout_merge_blocks (basic_block a,
     {
       rtx insn;

-      for (insn = BB_HEAD (b);
-          insn != NEXT_INSN (BB_END (b));
-          insn = NEXT_INSN (insn))
-       {
-         set_block_for_insn (insn, a);
-         df_insn_change_bb (insn);
-       }
+      update_bb_for_insns (BB_HEAD (b),
+                           NEXT_INSN (BB_END (b)), a);

       insn = BB_HEAD (b);
       /* Skip possible DELETED_LABEL insn.  */


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[steven at gcc dot gnu dot org]

------- Comment #17 from steven at gcc dot gnu dot org  2007-11-22 07:06 -------
I'd say s/update_bb_for_insns/update_bb_for_insn_chain/

And it doesn't hurt to set BLOCK_FOR_INSN, so now that the code is factored to
new functions, I'd also say
s/notify_bb_change_for_insns/update_bb_for_insn_chain/.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[spark at gcc dot gnu dot org]

------- Comment #18 from spark at gcc dot gnu dot org  2007-11-30 17:02 -------
Subject: Bug 34171

Author: spark
Date: Fri Nov 30 17:02:43 2007
New Revision: 130539

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=130539
Log:
gcc/testsuite/ChangeLog:

2007-11-30  Martin Michlmayr <tbm@cyrius.com>

        PR rtl-optimization/34171
        * gcc.dg/pr34171.c: New testcase.

gcc/ChangeLog:

2007-11-30  Seongbae Park <seongbae.park@gmail.com>

        PR rtl-optimization/34171
        * cfgrtl.c (update_bb_for_insn_chain): New function,
        refactored from update_bb_for_insn.
        (update_bb_for_insn): Call update_bb_for_insn.
        (rtl_merge_blocks, try_redirect_by_replacing_jump):
        Replace a loop with update_bb_for_insn_chain call.
        (cfg_layout_merge_blocks): Add a call to
        update_bb_for_insn_chain. Replace the for loop
        with a call to update_bb_for_insn_chain.


Added:
    trunk/gcc/testsuite/gcc.dg/pr34171.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgrtl.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171

[Bug rtl-optimization/34171] [4.3 Regression] Segfault in df_chain_remove_problem with -O3 on alpha

[jakub at gcc dot gnu dot org]

------- Comment #19 from jakub at gcc dot gnu dot org  2007-11-30 17:07 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34171