[Bug analyzer/96650] New: [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[Bug analyzer/96650] New: [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96650

            Bug ID: 96650
           Summary: [11 Regression] ICE in on_fact, at
                    analyzer/constraint-manager.cc:1785
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: analyzer
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-11.0.0-alpha20200816 snapshot (g:c99116aeeb9644ebddec653ee8b19de4d38b65bd)
ICEs when compiling the following testcase w/ -O2 -fanalyzer:

int *wf;

void
yd (void);

int
cy (void);

int *
ee (int hp)
{
  if (hp != 0)
    yd ();

  return 0;
}

void
z0 (int co)
{
  int l4 = sizeof (int);

 aq:
  wf = ee (l4);
  if (l4 < co)
    l4 = cy () + sizeof (int);
  goto aq;
}

% gcc-11.0.0 -O2 -fanalyzer -c apa68zkr.c
during IPA pass: analyzer
apa68zkr.c: In function 'z0':
apa68zkr.c:12:6: internal compiler error: in on_fact, at
analyzer/constraint-manager.cc:1785
   12 |   if (hp != 0)
      |      ^
0x7a3d5f ana::merger_fact_visitor::on_fact(ana::svalue const*, tree_code,
ana::svalue const*)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/tree.h:3409
0x7a3d5f ana::constraint_manager::for_each_fact(ana::fact_visitor*) const
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/constraint-manager.cc:1833
0x1849ed2 ana::constraint_manager::merge(ana::constraint_manager const&,
ana::constraint_manager const&, ana::constraint_manager*, ana::model_merger
const&)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/constraint-manager.cc:1812
0x110d5fb ana::region_model::can_merge_with_p(ana::region_model const&,
ana::program_point const&, ana::region_model*) const
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/region-model.cc:2501
0x110382f ana::program_state::can_merge_with_p(ana::program_state const&,
ana::program_point const&, ana::program_state*) const
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/program-state.cc:916
0x10f2788 ana::exploded_graph::get_or_create_node(ana::program_point const&,
ana::program_state const&, ana::exploded_node const*)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/engine.cc:1949
0x10f4157 ana::exploded_graph::process_node(ana::exploded_node*)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/engine.cc:2650
0x10f4d5a ana::exploded_graph::process_worklist()
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/engine.cc:2341
0x10f6e8f ana::impl_run_checkers(ana::logger*)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/engine.cc:4107
0x10f7aac ana::run_checkers()
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/engine.cc:4175
0x10ec468 execute
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200816/work/gcc-11-20200816/gcc/analyzer/analyzer-pass.cc:84

[Bug analyzer/96650] [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96650

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |11.0

[Bug analyzer/96650] [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96650

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2020-09-14
     Ever confirmed|0                           |1

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Thanks for filing this bug.  Confirmed.

[Bug analyzer/96650] [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96650

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by David Malcolm <dmalcolm@gcc.gnu.org>:

https://gcc.gnu.org/g:50ddbd0282e06614b29f0d3f3be5fbe70085a8bd

commit r11-3212-g50ddbd0282e06614b29f0d3f3be5fbe70085a8bd
Author: David Malcolm <dmalcolm@redhat.com>
Date:   Tue Sep 15 05:51:04 2020 -0400

    analyzer: fix ICE when merging constraints w/o transitivity [PR96650]

    PR analyzer/96650 reports an assertion failure when merging the
    intersection of two sets of constraints, due to the resulting
    constraints being infeasible.

    It turns out that the two input sets were each infeasible if
    transitivity were considered, but -fanalyzer-transitivity was off.
    However for this case, the merging code was "discovering" the
    transitive infeasibility of the intersection of the constraints even
    when -fanalyzer-transitivity is off, triggering an assertion failure.

    I attempted various fixes for this, but each of them would have
    introduced O(N^2) logic into the constraint-handling code into the
    -fno-analyzer-transitivity case (with N == the number of constraints).

    This patch fixes the ICE by tweaking the assertion, so that we
    silently drop such constraints if -fanalyzer-transitivity is off.

    gcc/analyzer/ChangeLog:
            PR analyzer/96650
            * constraint-manager.cc (merger_fact_visitor::on_fact): Replace
            assertion that add_constraint succeeded with an assertion that
            if it fails, -fanalyzer-transitivity is off.

    gcc/testsuite/ChangeLog:
            PR analyzer/96650
            * gcc.dg/analyzer/pr96650-1-notrans.c: New test.
            * gcc.dg/analyzer/pr96650-1-trans.c: New test.
            * gcc.dg/analyzer/pr96650-2-notrans.c: New test.
            * gcc.dg/analyzer/pr96650-2-trans.c: New test.

[Bug analyzer/96650] [11 Regression] ICE in on_fact, at analyzer/constraint-manager.cc:1785

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96650

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

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

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Should be fixed by the above commit.