[Bug c++/32716] New: Wrong code generation. Inlining problem.

[Bug c++/32716] New: Wrong code generation. Inlining problem.

[pranav dot bhandarkar at gmail dot com]

Generating wrong code for the following code snippet (test.C)
using namespace std;
#include <iostream>
class A { public:int a;};
class B: public virtual A { public:     A::a;};
class C : public virtual A { public:    A::a;};
class D : public C, public B {};
void h ( D &x )
{
        x.a++;
}
int main ()
{
       int result ;
        D d;
        d.a = 0;
        h (d);
        result = !(d.a==1);
        result ? cout<<"FAILED": cout <<"SUCCESS";
        return 0;
}
$>arm-none-eabi-g++ -O3 test.C
$> arm-none-eabi-run a.out
FAILED
$>arm-none-eabi-g++ -O3 test.C -fno-inline-functions
$> arm-none-eabi-run a.out
SUCCESS
$>arm-none-eabi-g++ --version
arm-none-eabi-g++ (GCC) 4.3.0 20070703 (experimental)
Copyright (C) 2007 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


-- 
           Summary: Wrong code generation. Inlining problem.
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pranav dot bhandarkar at gmail dot com
GCC target triplet: arm-none-eabi


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] Wrong code generation. Inlining problem.

[pranav dot bhandarkar at gmail dot com]

------- Comment #1 from pranav dot bhandarkar at gmail dot com  2007-07-10 10:02 -------
Created an attachment (id=13876)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13876&action=view)
Dump of the early inline pass, that highlights the problem with the inliner

h() gets inlined into main but the result of the increment in h() is not used
in main after inlining causing 0 to be assigned to result.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2007-07-10 11:29 -------
This is an aliasing problem (or rather a C++ FE problem):

  # SFT.41_31 = VDEF <SFT.41_30(D)>
  d.D.2508.a = 0;
  x.0_10 = (struct A *) &d;
...
  D.2747_16 = x.0_10 + D.2746_15;
  # VUSE <SFT.44_27>
  D.2748_17 = D.2747_16->a;
  D.2749_18 = D.2748_17 + 1;
  # SFT.44_34 = VDEF <SFT.44_27>
  D.2747_16->a = D.2749_18;
  # VUSE <SFT.41_31>
  D.2707_1 = d.D.2508.a;
  D.2706_2 = D.2707_1 != 1;
  return D.2706_2;

note how we don't identify the contrived access through the virtual base
with the zero-initialization and use in main().  Instead, it seems to
alias with

  iftmp.1_6 = (int (*__vtbl_ptr_type) (void) *) D.2735_5;
  # SFT.44_21 = VDEF <SFT.44_20(D)>
  d.D.2504._vptr.C = iftmp.1_6;
...
  # SFT.44_27 = VDEF <SFT.44_21>
  d.D.2504._vptr.C = &_ZTV1D[3];


Of course the original trees created for the virtual base access is
"somewhat" contrieved:

  (void) ((struct A *) (struct D *) x + (long unsigned int) *(long int *)
(((struct D *) x)->D.2504._vptr.C + 0xffffffffffffffffffffffffffffffe8))->a++ ;

while in main() we manage to do:

    struct D d;
  <<cleanup_point <<< Unknown tree: expr_stmt
  __comp_ctor  (&d) >>>
>>;
  <<cleanup_point <<< Unknown tree: expr_stmt
  (void) (d.D.2508.a = 0) >>>
>>;
  <<cleanup_point <<< Unknown tree: expr_stmt
  h ((struct D &) &d) >>>
>>;
  return <retval> = d.D.2508.a != 1;


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org, rguenth at gcc dot gnu
                   |                            |dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
 GCC target triplet|arm-none-eabi               |
           Keywords|                            |alias, wrong-code
      Known to fail|                            |4.2.0 4.2.1 4.3.0
      Known to work|                            |4.1.2
   Last reconfirmed|0000-00-00 00:00:00         |2007-07-10 11:29:31
               date|                            |
            Summary|Wrong code generation.      |[4.2/4.3 Regression] Wrong
                   |Inlining problem.           |code generation. Alias and
                   |                            |C++ virtual bases problem.
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2007-07-10 12:52 -------
Fixed with "take3.diff".


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[ramana dot radhakrishnan at celunite dot com]

------- Comment #4 from ramana dot radhakrishnan at celunite dot com  2007-07-10 15:14 -------
(In reply to comment #3)
> Fixed with "take3.diff".
> 

Did you forget to attach take3.diff ? 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[rguenther at suse dot de]

------- Comment #5 from rguenther at suse dot de  2007-07-10 15:32 -------
Subject: Re:  [4.2/4.3 Regression] Wrong code generation.
 Alias and C++ virtual bases problem.

On Tue, 10 Jul 2007, ramana dot radhakrishnan at celunite dot com wrote:

> ------- Comment #4 from ramana dot radhakrishnan at celunite dot com  2007-07-10 15:14 -------
> (In reply to comment #3)
> > Fixed with "take3.diff".
> > 
> 
> Did you forget to attach take3.diff ? 

No, that was a hint to Danny ;)

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[dberlin at dberlin dot org]

------- Comment #6 from dberlin at gcc dot gnu dot org  2007-07-10 16:59 -------
Subject: Re:  [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual
bases problem.

On 10 Jul 2007 15:32:51 -0000, rguenther at suse dot de
<gcc-bugzilla@gcc.gnu.org> wrote:
>
>
> ------- Comment #5 from rguenther at suse dot de  2007-07-10 15:32 -------
> Subject: Re:  [4.2/4.3 Regression] Wrong code generation.
>  Alias and C++ virtual bases problem.
>
> On Tue, 10 Jul 2007, ramana dot radhakrishnan at celunite dot com wrote:
>
> > ------- Comment #4 from ramana dot radhakrishnan at celunite dot com  2007-07-10 15:14 -------
> > (In reply to comment #3)
> > > Fixed with "take3.diff".
> > >
> >
> > Did you forget to attach take3.diff ?
>
> No, that was a hint to Danny ;)


You never told me whether omnetpp/xalanbmc were still failing with it or not :)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[rguenther at suse dot de]

------- Comment #7 from rguenther at suse dot de  2007-07-11 08:32 -------
Subject: Re:  [4.2/4.3 Regression] Wrong code generation.
 Alias and C++ virtual bases problem.

On Tue, 10 Jul 2007, dberlin at dberlin dot org wrote:

> On 10 Jul 2007 15:32:51 -0000, rguenther at suse dot de
> <gcc-bugzilla@gcc.gnu.org> wrote:
> >
> >
> > ------- Comment #5 from rguenther at suse dot de  2007-07-10 15:32 -------
> > Subject: Re:  [4.2/4.3 Regression] Wrong code generation.
> >  Alias and C++ virtual bases problem.
> >
> > On Tue, 10 Jul 2007, ramana dot radhakrishnan at celunite dot com wrote:
> >
> > > ------- Comment #4 from ramana dot radhakrishnan at celunite dot com  2007-07-10 15:14 -------
> > > (In reply to comment #3)
> > > > Fixed with "take3.diff".
> > > >
> > >
> > > Did you forget to attach take3.diff ?
> >
> > No, that was a hint to Danny ;)
> 
> 
> You never told me whether omnetpp/xalanbmc were still failing with it or not :)

Doh!  Yes, they did.  You never got around sending me the variant with
more asserts either ;)

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.0                       |4.2.1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.1                       |4.2.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[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=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[dberlin at gcc dot gnu dot org]

------- Comment #8 from dberlin at gcc dot gnu dot org  2007-08-19 23:23 -------
Subject: Bug 32716

Author: dberlin
Date: Sun Aug 19 23:23:29 2007
New Revision: 127629

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=127629
Log:
2007-08-19  Daniel Berlin  <dberlin@dberlin.org>

        Fix PR 32772
        Fix PR 32716
        Fix PR 32328
        Fix PR 32303

        * tree-flow.h (struct stmt_ann_d): Remove makes_clobbering_call.
        * tree-ssa-alias.c (init_transitive_clobber_worklist): Add
        on_worklist argument and avoid adding things to worklist multiple
        times.
        (add_to_worklist): Ditto.
        (mark_aliases_call_clobbered): Mark entire structure clobbered if
        single SFT is clobbered.
        (set_initial_properties): Ditto.
        (compute_call_clobbered): Update for changes to function
        arguments.
        (create_overlap_variables_for): Always create SFT for offset 0.
        (create_structure_vars): Handle PHI's, since we are in SSA form at
        this point.
        * tree-ssa-loop-ivopts.c (get_ref_tag): Don't return subvars.
        * tree-ssa-operands.c (access_can_touch_variable): Don't handle
        TARGET_MEM_REF.
        (add_vars_for_offset): Figure out aliases from access + points-to.
        (add_virtual_operand): Use add_vars-for_offset.
        (get_tmr_operands): Update for NMT changes, rewrite to be correct.
        (add_call_clobber_ops): Remove makes_clobbering_call set.
        (get_expr_operands): Always pass through the INDIRECT_REF
        reference.
        * tree-ssa-structalias.c (struct constraint_graph): Remove
        variables member.
        Add pe, pe_rep, pointer_label, loc_label, pointed_by, points_to,
        address_taken, pt_used, number_incoming.
        (FIRST_ADDR_NODE): Removed.
        (merge_graph_nodes): Remove broken code for the moment.
        (init_graph): New function.
        (build_pred_graph): Remove code to init_graph.
        Add location equivalence support.
        (struct scc_info): Rename roots to deleted.
        (scc_visit): Ditto.
        (init_scc_info): Ditto
        (init_topo_info): Use graph->size.
        (compute_topo_order): Ditto.
        (do_da_constraint): Removed.
        (do_sd_constraint): Remove calls to find().
        set_union_with_increment should always get 0 as last arg here.
        (do_complex_constraint): Replace do_da_constraint with assert.
        Stop calling find.
        (struct equiv_class_label): New.
        (pointer_equiv_class_table): Ditto.
        (location_equiv_class_table): Ditto.
        (equiv_class_label_hash): Ditto.
        (equiv_class_label_eq): Ditto
        (equiv_class_lookup): Ditto.
        (equiv_class_ladd): Ditto.
        (pointer_equiv_class): Ditto.
        (location_equiv_class): Ditto.
        (condense_visit): Rename and rewrite from label_visit to do only
        SCC related stuff for HU.
        (label_visit): Do HU work for HU.
        (perform_var_substitution): Update to do HU and location
        equivalence.
        (free_var_substitution_info): Update to free HU and location
        equivalence structures.  */
        (find_equivalent_node): Update for pointer but not location
        equivalence.
        (unite_pointer_equivalences): New function.
        (move_complex_constraints): Rewrite to only do moving.
        (rewrite_constraints): Split out of move_complex_constraints.
        (solve_graph): Use graph->size.
        (process_constraint_1): Add from_call argument, use it.
        Split *a = &b into two constraints.
        (process_constraint): Use new process_constraint_1.
        (get_constraint_for_component_ref): Handle bitmaxsize == -1 case.
        (get_constraint_for): Handle non-pointer integers properly.
        Remove code that used to handle structures.
        (handle_ptr_arith): Fix a few bugs in pointer arithmetic handling
        with unknown addends.
        (handle_rhs_call): New function.
        (find_func_aliases): Use handle_rhs_call.
        (set_uids_in_ptset): Add an assert.
        (set_used_smts): Fix bug in not considering unified vars.
        (compute_tbaa_pruning): Stop initing useless iteration_obstack.
        (compute_points_to_sets): Update for other function changes.
        (delete_points_to_sets): Ditto.
        (ipa_pta_execute): Ditto.
        (pass_ipa_pta): We need to update SSA after ipa_pta.



Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-flow.h
    trunk/gcc/tree-ssa-alias.c
    trunk/gcc/tree-ssa-loop-ivopts.c
    trunk/gcc/tree-ssa-operands.c
    trunk/gcc/tree-ssa-structalias.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[dberlin at gcc dot gnu dot org]

------- Comment #9 from dberlin at gcc dot gnu dot org  2007-08-20 01:54 -------
All should be fixed


-- 

dberlin at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2/4.3 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[ht990332 at gmail dot com]

------- Comment #10 from ht990332 at gmail dot com  2007-08-20 08:51 -------
Will 4.2.2 get this fix or only trunk?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2007-08-20 09:27 -------
Re-opening, 4.2 is still affected.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
      Known to fail|4.2.0 4.2.1 4.3.0           |4.2.0 4.2.1
      Known to work|4.1.2                       |4.1.2 4.3.0
         Resolution|FIXED                       |
            Summary|[4.2/4.3 Regression] Wrong  |[4.2 Regression] Wrong code
                   |code generation. Alias and  |generation. Alias and C++
                   |C++ virtual bases problem.  |virtual bases problem.


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[mmitchel at gcc dot gnu dot org]

------- Comment #12 from mmitchel at gcc dot gnu dot org  2007-10-09 19:20 -------
Change target milestone to 4.2.3, as 4.2.2 has been released.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.2                       |4.2.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[jsm28 at gcc dot gnu dot org]

------- Comment #13 from jsm28 at gcc dot gnu dot org  2008-02-01 16:54 -------
4.2.3 is being released now, changing milestones of open bugs to 4.2.4.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.3                       |4.2.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[jsm28 at gcc dot gnu dot org]

------- Comment #14 from jsm28 at gcc dot gnu dot org  2008-05-19 20:23 -------
4.2.4 is being released, changing milestones to 4.2.5.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.2.4                       |4.2.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[ramana at icerasemi dot com]

------- Comment #15 from ramana at icerasemi dot com  2009-01-15 10:41 -------
Add self to CC


-- 

ramana at icerasemi dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ramana dot r at gmail dot
                   |                            |com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716

[Bug c++/32716] [4.2 Regression] Wrong code generation. Alias and C++ virtual bases problem.

[jsm28 at gcc dot gnu dot org]

------- Comment #16 from jsm28 at gcc dot gnu dot org  2009-03-30 22:11 -------
Closing 4.2 branch, fixed in 4.3.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
      Known to fail|4.2.0 4.2.1                 |4.2.0 4.2.1 4.2.5
         Resolution|                            |FIXED
   Target Milestone|4.2.5                       |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32716