[Bug c++/97186] New: [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[Bug c++/97186] New: [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

            Bug ID: 97186
           Summary: [11 Regression] ICE: Segmentation fault (in
                    maybe_instantiate_noexcept)
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

g++-11.0.0-alpha20200920 snapshot (g:363e7755f227656684c8e284307ceee451503ca4)
ICEs when compiling the following testcase:

template <class GG>
struct no {
  static void
  tg ()
  {
    void
    hk () noexcept (tg);

    hk ();
  }
};

void
os ()
{
  no<int> ().tg ();
}

% g++-11.0.0 -c n8bpixef.cc
n8bpixef.cc: In instantiation of 'void hk()':
n8bpixef.cc:9:8:   required from 'static void no<GG>::tg() [with GG = int]'
n8bpixef.cc:16:18:   required from here
n8bpixef.cc:7:5: internal compiler error: Segmentation fault
    7 |     hk () noexcept (tg);
      |     ^~
0x100af6f crash_signal
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/toplev.c:327
0xa1ca2f maybe_instantiate_noexcept(tree_node*, int)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/tree.h:3298
0x95054a mark_used(tree_node*, int)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/decl2.c:5549
0xa6c9eb finish_id_expression_1
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/semantics.c:3999
0xa6cb17 finish_id_expression(tree_node*, tree_node*, tree_node*, cp_id_kind*,
bool, bool, bool*, bool, bool, bool, bool, char const**, unsigned int)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/semantics.c:4063
0xa18554 tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:19326
0xa18cbd tsubst_copy_and_build(tree_node*, tree_node*, int, tree_node*, bool,
bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:19885
0xa2386f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:18889
0xa25bc9 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:17991
0xa25fa1 tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:17961
0xa24f2e tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:18281
0xa2c70f tsubst_expr(tree_node*, tree_node*, int, tree_node*, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:17946
0xa2c70f instantiate_body
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:25577
0xa2d88f instantiate_decl(tree_node*, bool, bool)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:25865
0xa4ff9b instantiate_pending_templates(int)
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/pt.c:25944
0x95175b c_parse_final_cleanups()
       
/var/tmp/portage/sys-devel/gcc-11.0.0_alpha20200920/work/gcc-11-20200920/gcc/cp/decl2.c:4920

clang 10.0.1 accepts it.

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

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

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

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-09-24
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |nathan at gcc dot gnu.org

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Started to ICE with r11-3192-ge9fdb9a73249f95f, before that it was rejected:

g++-10 pr97186.C -c
pr97186.C: In instantiation of ‘void hk() [with GG = int]’:
pr97186.C:9:8:   required from ‘static void no<GG>::tg() [with GG = int]’
pr97186.C:16:18:   required from here
pr97186.C:7:5: error: conversion from ‘void (*)()’ to ‘bool’ in a converted
constant expression
    7 |     hk () noexcept (tg);
      |     ^~
pr97186.C:7:5: error: could not convert ‘no<int>::tg’ from ‘void()’ to ‘bool’

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |nathan at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

--- Comment #2 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
The error abount conversion failure, if it is a bug, is unrelated to the ICE. 
I say 'if', because I think there have been changes in regards to whether
functions decay to pointers which can be implicitly converted to bool in
constant exprs.  Not digging into that right now though.

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathan Sidwell <nathan@gcc.gnu.org>:

https://gcc.gnu.org/g:2e66e53b1efb98f5cf6b0a123990c1ca999affd7

commit r11-3436-g2e66e53b1efb98f5cf6b0a123990c1ca999affd7
Author: Nathan Sidwell <nathan@acm.org>
Date:   Thu Sep 24 06:17:00 2020 -0700

    c++: local-decls are never member fns [PR97186]

    This fixes an ICE in noexcept instantiation.  It was presuming
    functions always have template_info, but that changed with my
    DECL_LOCAL_DECL_P changes.  Fortunately DECL_LOCAL_DECL_P fns are
    never member fns, so we don't need to go fishing out a this pointer.

    Also I realized I'd misnamed local10.C, so renaming it local-fn3.C,
    and while there adding the effective-target lto that David E pointed
    out was missing.

            PR c++/97186
            gcc/cp/
            * pt.c (maybe_instantiate_noexcept): Local externs are never
            member fns.
            gcc/testsuite/
            * g++.dg/template/local10.C: Rename ...
            * g++.dg/template/local-fn3.C: .. here.  Require lto.
            * g++.dg/template/local-fn4.C: New.

[Bug c++/97186] [11 Regression] ICE: Segmentation fault (in maybe_instantiate_noexcept)

[nathan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97186

Nathan Sidwell <nathan at gcc dot gnu.org> changed:

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

--- Comment #4 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
Fixed 2e66e53b1ef

if you think the code should be accepted without error please file a separate
defect.