[Bug c/25514] New: [m68k] internal consistency failure

[Bug c/25514] New: [m68k] internal consistency failure

[stephen at marenka dot net]

Recent versions of make fail with an error reproducible as follows.

$ gcc -O2 -c -o buggy.o buggy.c
buggy.c: In function 'pop_variable_scope':
buggy.c:62: fatal error: internal consistency failure
compilation terminated.

Workaround: change -O2 to -O1.


-- 
           Summary: [m68k] internal consistency failure
           Product: gcc
           Version: 4.0.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: stephen at marenka dot net
 GCC build triplet: m68k-linux-gnu
  GCC host triplet: m68k-linux-gnu
GCC target triplet: m68k-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug c/25514] [m68k] internal consistency failure

[stephen at marenka dot net]

------- Comment #1 from stephen at marenka dot net  2005-12-21 14:12 -------
Created an attachment (id=10544)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10544&action=view)
Test Case


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[stephen at marenka dot net]

------- Comment #2 from stephen at marenka dot net  2006-02-01 16:28 -------
Also fails with gcc-4.1 (debian 4.1-0exp4).


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2006-02-02 19:32 -------
Reduced testcase on the mainline:
void __attribute__((const)) g(void);
struct variable_set{int i;};
struct variable_set_list
{
    struct variable_set_list *next;
    struct variable_set *set;
};
extern struct variable_set_list *current_variable_set_list;
static struct variable_set global_variable_set;
static struct variable_set_list global_setlist  = { 0, &global_variable_set };
void pop_variable_scope (void)
{
  struct variable_set_list *setlist;
  if (current_variable_set_list->next == 0)
    g();
  if (current_variable_set_list != &global_setlist)
    {
      setlist = current_variable_set_list;
      current_variable_set_list = setlist->next;
    }
  else
    {
      setlist = global_setlist.next;
      global_setlist.set = setlist->set;
      global_setlist.next = setlist->next;
    }
  free ((char *) setlist);
}


-- 

pinskia 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         |2006-02-02 19:32:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #4 from rsandifo at gcc dot gnu dot org  2006-04-25 14:23 -------
This issue is related to PR22002.  I have a patch.

A slightly-more reduced testcase is:

struct node { struct node *next; int value; };
struct node *current_node, global_list;

void
bar (void)
{
  struct node *node, *next;

  node = current_node;
  next = node->next;
  if (node != &global_list)
    current_node = next;
  else
    {
      node = global_list.next;
      global_list.value = node->value;
      global_list.next = node->next;
    }
  foo (node);
}


-- 

rsandifo at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rsandifo at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-02-02 19:32:25         |2006-04-25 14:23:53
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #5 from rsandifo at gcc dot gnu dot org  2006-04-27 16:41 -------
Subject: Bug 25514

Author: rsandifo
Date: Thu Apr 27 16:41:51 2006
New Revision: 113312

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113312
Log:
        PR rtl-optimization/25514
        * combine.c (replaced_rhs_insn): New variable.
        (combine_instructions): Set replaced_rhs_insn when trying to replace
        a SET_SRC with a REG_EQUAL note.
        (distribute_notes): Use replaced_rhs_insn when determining the live
        range of a REG_DEAD register.

gcc/testsute
        * gcc.c-torture/compile/pr25514.c: New test.

Modified:
    branches/csl/coldfire-4_1/ChangeLog.csl
    branches/csl/coldfire-4_1/gcc/combine.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #6 from rsandifo at gcc dot gnu dot org  2006-04-27 16:43 -------
Subject: Bug 25514

Author: rsandifo
Date: Thu Apr 27 16:43:10 2006
New Revision: 113313

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113313
Log:
        PR rtl-optimization/25514
        * combine.c (replaced_rhs_insn): New variable.
        (combine_instructions): Set replaced_rhs_insn when trying to replace
        a SET_SRC with a REG_EQUAL note.
        (distribute_notes): Use replaced_rhs_insn when determining the live
        range of a REG_DEAD register.

gcc/testsute
        * gcc.c-torture/compile/pr25514.c: New test.

Added:
    branches/csl/coldfire-4_1/gcc/testsuite/gcc.c-torture/compile/pr25514.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[patchapp at dberlin dot org]

------- Comment #7 from patchapp at dberlin dot org  2006-05-10 13:52 -------
Subject: Bug number PR25514

A patch for this bug has been added to the patch tracker.
The mailing list url for the patch is
http://gcc.gnu.org/ml/gcc-patches/2006-04/msg00958.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [m68k] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #8 from rsandifo at gcc dot gnu dot org  2006-05-22 15:58 -------
Subject: Bug 25514

Author: rsandifo
Date: Mon May 22 15:58:03 2006
New Revision: 113983

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=113983
Log:
        PR rtl-optimization/25514
        * combine.c (replaced_rhs_insn): New variable.
        (combine_instructions): Set replaced_rhs_insn when trying to replace
        a SET_SRC with a REG_EQUAL note.
        (distribute_notes): Use replaced_rhs_insn when determining the live
        range of a REG_DEAD register.

gcc/testsute
        * gcc.c-torture/compile/pr25514.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr25514.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [4.0, 4.1 regression] [m68k] internal consistency failure

[jbglaw at lug-owl dot de]

------- Comment #9 from jbglaw at lug-owl dot de  2006-05-23 07:54 -------
Bisected down to r113983 (which was ment to fix this problem for m68k), I'm
getting exactly this "internal consistency failure" when compiling parts of
uClibc for vax-linux-uClibc. (That is, starting with r113981:-)  From reading
the mailing lists, this also happens for the hppa and ia64 ports.


-- 

jbglaw at lug-owl dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jbglaw at lug-owl dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [4.0, 4.1 regression] [m68k] internal consistency failure

[jsm28 at gcc dot gnu dot org]

-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug target/25514] [4.0, 4.1 regression] [m68k] internal consistency failure

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0, 4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #10 from ebotcazou at gcc dot gnu dot org  2006-11-02 07:42 -------
Richard, I'm on another problem related to REG_NOTEs in the combiner (PR 29329)
present on the 4.1 branch so I think it's time to make a definitive decision on
this PR.

I'd be in favor of backporting all your changes to the 4.1 branch but I'll let
you and Roger decide.  Thanks in advance.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sayle at gcc dot gnu dot
                   |                            |org, ebotcazou at gcc dot
                   |                            |gnu dot org
          Component|target                      |rtl-optimization
            Summary|[4.0, 4.1 regression] [m68k]|[4.0, 4.1 regression]
                   |internal consistency failure|internal consistency failure


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #11 from rsandifo at gcc dot gnu dot org  2006-11-02 07:55 -------
Ack that, thanks Eric.  Roger and I did discuss this a bit
off-list, but I don't think we came to any conclusion.
(Tardiness on my part being the dominant problem, sorry.)

I think Roger is OK in principle with a backport, but the
questions are (a) whether we should keep your patch on
mainline too and, if not, (b) whether we should revert
it on the branches too.  Roger, let me know if I've
misrepresented you there.

Richard


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #12 from ebotcazou at gcc dot gnu dot org  2006-11-02 08:03 -------
> I think Roger is OK in principle with a backport, but the
> questions are (a) whether we should keep your patch on
> mainline too and, if not, (b) whether we should revert
> it on the branches too.  Roger, let me know if I've
> misrepresented you there.

I don't think my patch should be taken into account to make the decision.
However, I can first revert it everywhere to make the backport easier.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #13 from ebotcazou at gcc dot gnu dot org  2006-11-16 13:08 -------
Ping. :-)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #14 from ebotcazou at gcc dot gnu dot org  2006-12-21 22:27 -------
Not sure what to think about the current state of affairs of the 4.1 branch
and, consequently, about this PR.  Anyone?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[mmitchel at gcc dot gnu dot org]

------- Comment #15 from mmitchel at gcc dot gnu dot org  2007-01-05 17:39 -------
Eric asked me to weigh in here.  My only concern about a backport is Comment
#9, which suggests that the patch didn't work.  I'm assuming that since we're
all talking about backporting it, that comment was mistaken?  If indeed there
are no known problems, I think it's reasonable to put this on 4.1.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #16 from ebotcazou at gcc dot gnu dot org  2007-01-05 18:10 -------
> Eric asked me to weigh in here.  My only concern about a backport is Comment
> #9, which suggests that the patch didn't work.  I'm assuming that since we're
> all talking about backporting it, that comment was mistaken?  If indeed there
> are no known problems, I think it's reasonable to put this on 4.1.

Thanks Mark.  It seems that a whole new class of internal consistency failures
due to the mishandling of REG_NOTEs in the combiner appeared in 4.1.x (for
example rtl-optimization/28243 and the blocked rtl-optimization/29329) and up.
Richard's patch is the most generic fix available as of today, so backporting
it or not to the 4.1.x branch has cascading effects on the other PRs.  Maybe
the problem reported in comment #9 is another variant.

Richard, are you still ready to backport it?  If so, I can revert my patch for
rtl-optimization/28243 right now to make things easier.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mark at codesourcery dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[mark at codesourcery dot com]

------- Comment #17 from mark at codesourcery dot com  2007-01-05 18:13 -------
Subject: Re:  [4.0/4.1 regression] internal consistency
 failure

ebotcazou at gcc dot gnu dot org wrote:

> Thanks Mark.  It seems that a whole new class of internal consistency failures
> due to the mishandling of REG_NOTEs in the combiner appeared in 4.1.x (for
> example rtl-optimization/28243 and the blocked rtl-optimization/29329) and up.
> Richard's patch is the most generic fix available as of today, so backporting
> it or not to the 4.1.x branch has cascading effects on the other PRs.  Maybe
> the problem reported in comment #9 is another variant.

Do you mean positive cascading effects, in that bugs go away, or
negative, in that new bugs show up?  Do you think that backporting this
patch is going to fix some bugs at the expense of breaking others?

Thanks,


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #18 from ebotcazou at gcc dot gnu dot org  2007-01-05 18:33 -------
> Do you mean positive cascading effects, in that bugs go away, or
> negative, in that new bugs show up?

Positive cascading effects if the set of patch is backported to the branch.

> Do you think that backporting this patch is going to fix some bugs at the
> expense of breaking others?

That will very likely fix again 28243 and help for 29329.  I can make a quick
pass on the various related PRs for mainline/4.2/4.1 over the week-end and
post kind of an overview of the situation before you definitely decide.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[mark at codesourcery dot com]

------- Comment #19 from mark at codesourcery dot com  2007-01-05 18:37 -------
Subject: Re:  [4.0/4.1 regression] internal consistency
 failure

ebotcazou at gcc dot gnu dot org wrote:
> ------- Comment #18 from ebotcazou at gcc dot gnu dot org  2007-01-05 18:33 -------
>> Do you mean positive cascading effects, in that bugs go away, or
>> negative, in that new bugs show up?
> 
> Positive cascading effects if the set of patch is backported to the branch.
> 
>> Do you think that backporting this patch is going to fix some bugs at the
>> expense of breaking others?
> 
> That will very likely fix again 28243 and help for 29329.  I can make a quick
> pass on the various related PRs for mainline/4.2/4.1 over the week-end and
> post kind of an overview of the situation before you definitely decide.

I think I can do best by deferring to you, Roger, and Richard.

It sounds like everyone's agreed that Richard's changes are the right
thing, in principle.  It also sounds like they have had little (no?)
negative affect in practice.  As long as we don't feel that we're unduly
introducing risk (fixing one thing but breaking another), I'm all for
putting the patches on the branch.

I know Richard's busy (he's getting ready to submit a big batch of
changes), so if you feel like trying the backport you might want to give
it a go.  Otherwise, I'm sure Richard will get to it in the relatively
near future.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #20 from ebotcazou at gcc dot gnu dot org  2007-01-05 19:03 -------
> I know Richard's busy (he's getting ready to submit a big batch of
> changes), so if you feel like trying the backport you might want to give
> it a go.  Otherwise, I'm sure Richard will get to it in the relatively
> near future.

OK, I'm going to give it a whirl.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[richard at nildram dot co dot uk]

------- Comment #21 from richard at nildram dot co dot uk  2007-01-06 08:42 -------
Subject: Re:  [4.0/4.1 regression] internal consistency failure

"ebotcazou at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:
>> Eric asked me to weigh in here.  My only concern about a backport is Comment
>> #9, which suggests that the patch didn't work.  I'm assuming that since we're
>> all talking about backporting it, that comment was mistaken?  If indeed there
>> are no known problems, I think it's reasonable to put this on 4.1.
>
> Thanks Mark.  It seems that a whole new class of internal consistency failures
> due to the mishandling of REG_NOTEs in the combiner appeared in 4.1.x (for
> example rtl-optimization/28243 and the blocked rtl-optimization/29329) and up.
> Richard's patch is the most generic fix available as of today, so backporting
> it or not to the 4.1.x branch has cascading effects on the other PRs.  Maybe
> the problem reported in comment #9 is another variant.
>
> Richard, are you still ready to backport it?  If so, I can revert my patch for
> rtl-optimization/28243 right now to make things easier.

Yup, I'm still ready to backport it if the consensus is that
the patch is OK for 4.1.  I see from later comments that you
might be backporting it yourself, but the offer still stands
if you haven't started yet.

Richard


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #22 from ebotcazou at gcc dot gnu dot org  2007-01-06 08:53 -------
> Yup, I'm still ready to backport it if the consensus is that
> the patch is OK for 4.1.  I see from later comments that you
> might be backporting it yourself, but the offer still stands
> if you haven't started yet.

I only resynced my 4.1 branch (it changed a lot recently) and got a baseline,
so I've not really started.  OK, please do it and I'll only do the reversion
of my patch on all branches.  Thanks again.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0/4.1 regression] internal consistency failure

[rsandifo at gcc dot gnu dot org]

------- Comment #23 from rsandifo at gcc dot gnu dot org  2007-01-06 14:27 -------
Subject: Bug 25514

Author: rsandifo
Date: Sat Jan  6 14:26:58 2007
New Revision: 120526

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=120526
Log:
gcc/
        Backport:

        2006-05-23  Richard Sandiford  <richard@codesourcery.com>

        PR rtl-optimization/27736
        * combine.c (replaced_rhs_value): New variable.
        (combine_instructions): Set it.
        (distribute_notes): When distributing a note in replaced_rhs_insn,
        check whether the value was used in replaced_rhs_value.

        2006-05-22  Richard Sandiford  <richard@codesourcery.com>

        PR rtl-optimization/25514
        * combine.c (replaced_rhs_insn): New variable.
        (combine_instructions): Set replaced_rhs_insn when trying to replace
        a SET_SRC with a REG_EQUAL note.
        (distribute_notes): Use replaced_rhs_insn when determining the live
        range of a REG_DEAD register.

gcc/testsuite/
        2006-05-22  Richard Sandiford  <richard@codesourcery.com>

        PR rtl-optimization/25514
        * gcc.c-torture/compile/pr25514.c: New test.

Added:
    branches/gcc-4_1-branch/gcc/testsuite/gcc.c-torture/compile/pr25514.c
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/combine.c
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514

[Bug rtl-optimization/25514] [4.0 regression] internal consistency failure

[ebotcazou at gcc dot gnu dot org]

------- Comment #24 from ebotcazou at gcc dot gnu dot org  2007-02-10 15:10 -------
Fixed in upcoming 4.1.2, the 4.0 branch is now closed.


-- 

ebotcazou at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|3.4.3 4.2.0 4.1.0           |3.4.3 4.2.0 4.1.2
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25514