[Bug c++/31505] New: Canonical types failures

[Bug c++/31505] New: Canonical types failures

[bangerth at dealii dot org]

For the attached (unfortunately rather lengthy) file I finally managed
to get a reproducible testcase that spews out several pages of
canonical types warning messages when compiled with -O2 (but not with
-O0):

examples/step-27> /tmp/bangerth/bin/gcc-mainline/bin/g++ -c step-27.ii -O2
step-27.cc: In member function 'void LaplaceProblem<dim>::create_coarse_grid()
[with int dim = 2]':
step-27.cc:742: warning: same canonical type node for different types
dealii::Point<2> [24] and const dealii::Point<2> [24]
 <array_type 0xb4cef8dc
    type <record_type 0xb7459bd0 Point sizes-gimplified addressable
needs-constructing type_1 type_5 type_6 BLK
        size <integer_cst 0xb7d5e834 constant invariant 128>
        unit size <integer_cst 0xb7d5e850 constant invariant 16>
        align 32 symtab 0 alias set 147 canonical type 0xb7459bd0
        fields <field_decl 0xb5f54a20 D.74077 type <record_type 0xb745472c
Tensor>
            ignored decl_6 BLK file
/tmp/bangerth/x/deal.II/base/include/base/tensor_base.h line 39 size
<integer_cst 0xb7d5e834 128> unit size <integer_cst 0xb7d5e850 16>
            align 32 offset_align 128
            offset <integer_cst 0xb7d5e444 constant invariant 0>
            bit offset <integer_cst 0xb7d5eb28 constant invariant 0> context
<record_type 0xb7459bd0 Point> chain <type_decl 0xb5f8a438 Point>> context
<namespace_decl 0xb7e25870 dealii>
       needs-constructor X() X(constX&) this=(X&) n_parents=1 use_template=1
interface-unknown
        pointer_to_this <pointer_type 0xb5f8a510> reference_to_this
<reference_type 0xb5f8e0d8> chain <type_decl 0xb7459c3c Point>>
    sizes-gimplified needs-constructing BLK
...

I hope this helps to track a few things down. I have a couple of other
files that show canonical types fail as well, but there the bug goes
away once one uses -save-temps :-(

Best
 Wolfgang


-- 
           Summary: Canonical types failures
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bangerth at dealii dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] Canonical types failures

[bangerth at dealii dot org]

------- Comment #1 from bangerth at dealii dot org  2007-04-07 16:55 -------
*** Bug 31506 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] Canonical types failures

[bangerth at dealii dot org]

------- Comment #2 from bangerth at dealii dot org  2007-04-07 16:59 -------
For some reason, bugzilla gives me an internal error when I try to attach
the file. In any case, it is here:
  http://www.math.tamu.edu/~bangerth/step-27.ii.gz


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] Canonical types failures

[pinskia at gcc dot gnu dot org]

------- Comment #3 from pinskia at gcc dot gnu dot org  2007-04-07 20:25 -------
Reducing.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] Canonical types failures

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2007-04-08 00:05 -------
I bet a beer that this is related to code like:
int a[] = {1,2};

The only reason I am saying that is because the last time I looked into a
failure of giving the same aliasing set to int[] = {1,2} as int[2] was the same
problem.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2007-04-08 05:55 -------
Reduced testcase (which makes I am correct):
template <int dim> struct Point 
{
        Point (const double x, const double y);
};
Point<2>  f(void) {}
void create_coarse_grid () {
        static const Point<2> vertices_1[]
        = {
                Point<2> (-1., -1.),
                Point<2> (-1./2, -1.),
                Point<2> (0., -1.),
                Point<2> (+1./2, -1.)
        };
}


=====================
If I change [] to [4] then it works.


-- 

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         |2007-04-08 05:55:43
               date|                            |
            Summary|Canonical types failures    |[4.3 Regression] Canonical
                   |                            |types failures
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[dgregor at gcc dot gnu dot org]

------- Comment #6 from dgregor at gcc dot gnu dot org  2007-04-09 10:39 -------
This is clearly my bug, but I am not able to reproduce it on i686-pc-linux-gnu. 

Does the following patch fix the problem?

  http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00188.html

If not, which platform are you seeing the problem on?


-- 

dgregor at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dgregor at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-04-08 05:55:43         |2007-04-09 10:39:33
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[bangerth at dealii dot org]

------- Comment #7 from bangerth at dealii dot org  2007-04-09 14:49 -------
(In reply to comment #6)
> This is clearly my bug, but I am not able to reproduce it on i686-pc-linux-gnu. 

This was with r123617, on i686-pc-linux-gnu. I can reproduce with this
version and Andrew's testcase, though only with -O2. Did you try it with
this flag?

W.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[bangerth at dealii dot org]

------- Comment #8 from bangerth at dealii dot org  2007-04-09 14:56 -------
(In reply to comment #6)
> Does the following patch fix the problem?
> 
>   http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00188.html

Yes. I think it would be good if you added Andrew's testcase to the patch
as well, compiled with -O2.

W.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[dgregor at gcc dot gnu dot org]

------- Comment #9 from dgregor at gcc dot gnu dot org  2007-04-09 15:09 -------
I can't reproduce this bug with r123671 on i686-pc-linux-gnu. However, since
the above patch does fix the problem, I'll add this PR to the ChangeLog for
that patch.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[bangerth at dealii dot org]

------- Comment #10 from bangerth at dealii dot org  2007-04-09 15:23 -------
Great, thanks. Hopefully someone approves the patch soon.

Talking about canonical types: I think the idea of only issuing a warning
in cases like the current one is a really bad idea. Warnings are meant for
things where the programmer did something dubious (if correct) and that
can be silenced by adjusting the source code. On the other hand, what we
have here is a compiler whose internal data structures have become corrupted.
That's pretty much the definition of what we use ICEs for, and I would urge
you to reconsider the idea of using a warning instead.

Does it matter? I do think so. For example, I found this one by actually 
looking at the log files of my automated compile jobs. It showed a successful
compilation, rather than a failure, because a warning still makes 'make' go
on as if nothing had happened. I'm sure canonical type failures would be
found quicker if their effect was more drastic, because it makes people
look for the place where something goes wrong.

Best
  Wolfgang


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[gdr at cs dot tamu dot edu]

------- Comment #11 from gdr at cs dot tamu dot edu  2007-04-09 15:33 -------
Subject: Re:  [4.3 Regression] Canonical types failures

"bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Talking about canonical types: I think the idea of only issuing a warning
| in cases like the current one is a really bad idea.

Fully agreed.  I believe we discussed this on the main list.  It
should not be a warning.  It should be an ICE.  This is a compiler
bug.  That is what ICE is for.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

Re: [Bug c++/31505] [4.3 Regression] Canonical types failures

[Gabriel Dos Reis]

"bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| Talking about canonical types: I think the idea of only issuing a warning
| in cases like the current one is a really bad idea.

Fully agreed.  I believe we discussed this on the main list.  It
should not be a warning.  It should be an ICE.  This is a compiler
bug.  That is what ICE is for.

-- Gaby

[Bug c++/31505] [4.3 Regression] Canonical types failures

[steven at gcc dot gnu dot org]

------- Comment #12 from steven at gcc dot gnu dot org  2007-04-09 17:51 -------
Yay to making it an ICE instead of a warning. 


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|dgregor at gcc dot gnu dot  |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[steven at gcc dot gnu dot org]

-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dgregor at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505

[Bug c++/31505] [4.3 Regression] Canonical types failures

[dgregor at gcc dot gnu dot org]

------- Comment #13 from dgregor at gcc dot gnu dot org  2007-04-12 12:52 -------
Same problem/cause as 31103, which is now fixed on mainline.

*** This bug has been marked as a duplicate of 31103 ***


-- 

dgregor at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31505