[Bug c++/115239] New: ICE: internal compiler error: Segmentation fault

[Bug c++/115239] New: ICE: internal compiler error: Segmentation fault

[markus at oberhumer dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

            Bug ID: 115239
           Summary: ICE: internal compiler error: Segmentation fault
           Product: gcc
           Version: 14.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: markus at oberhumer dot com
  Target Milestone: ---

Link at Compiler Explorer:

  https://godbolt.org/z/b1oW566E5

I stumbled on this while compiling some invalid code during refactoring.

Test case has been reduced by cvise.

Discovered using gcc-14.1.1-4.fc40.x86_64. Might be a regression - gcc-13 does
not crash.

Acutal code: ```
constexpr bool foo(const char *, char *, long) { return true; }
constexpr bool foo(const char *, char *, unsigned) { return true; }
constexpr bool foo(char, char, long) { return true; }
constexpr bool foo(char, char, unsigned) { return true; }

static_assert(foo((char *)nullptr, nullptr, 0));
```

[Bug c++/115239] ICE: internal compiler error: Segmentation fault

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2024-05-27
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
[apinski@xeond2 gcc]$ ./cc1plus t.cc
 constexpr bool foo(const char*, char*, long int) constexpr bool foo(const
char*, char*, unsigned int) constexpr bool foo(char, char, long int) constexpr
bool foo(char, char, unsigned int)
t.cc: At global scope:
t.cc:7:18: internal compiler error: Segmentation fault
    7 | static_assert(foo((char *)nullptr, nullptr, 0));
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x134bdbf crash_signal
        /home/apinski/src/upstream-gcc-match/gcc/gcc/toplev.cc:319
0xa49a4e compare_ics
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/call.cc:12124
0xa5736a joust
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/call.cc:12958
0xa58ee8 tourney
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/call.cc:13476
0xa59068 perform_overload_resolution
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/call.cc:5006
0xa5db12 build_new_function_call(tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/call.cc:5098
0xcadf7d finish_call_expr(tree_node*, vec<tree_node*, va_gc, vl_embed>**, bool,
bool, int)
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/semantics.cc:3136
0xc0c2bb cp_parser_postfix_expression
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:8191
0xbe74f0 cp_parser_binary_expression
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:10411
0xbe82b4 cp_parser_assignment_expression
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:10755
0xbe93fd cp_parser_constant_expression
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:11045
0xbeb84b cp_parser_static_assert
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:17096
0xc32672 cp_parser_declaration
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:15706
0xc336fa cp_parser_toplevel_declaration
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:15727
0xc336fa cp_parser_translation_unit
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:5297
0xc336fa c_parse_file()
        /home/apinski/src/upstream-gcc-match/gcc/gcc/cp/parser.cc:51518
0xd81961 c_common_parse_file()
        /home/apinski/src/upstream-gcc-match/gcc/gcc/c-family/c-opts.cc:1311
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call from static_assert in some cases

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE: internal compiler      |[14/15 Regression] ICE:
                   |error: Segmentation fault   |Segmentation fault with
                   |                            |ambiguous function call
                   |                            |from static_assert in some
                   |                            |cases
   Target Milestone|---                         |14.2

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call from static_assert in some cases

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 58294
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58294&action=edit
Reduced further

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call in some cases

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #58294|0                           |1
        is obsolete|                            |

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 58295
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58295&action=edit
Reduced further, removed one argument

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-bisection             |
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |ppalka at gcc dot gnu.org
            Summary|[14/15 Regression] ICE:     |[14/15 Regression] ICE:
                   |Segmentation fault with     |Segmentation fault with
                   |ambiguous function call in  |ambiguous function call in
                   |some cases (`const char*`   |some cases (`const char*`
                   |vs `char` with `long` vs    |vs `char` with `long` vs
                   |`unsigned`)                 |`unsigned`) since r14-6522

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r14-6522-gb24c09bfb626271cda345f5a6f0d3a6b6480593d

[Bug c++/115239] [14/15 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:7fed7e9bbc57d502e141e079a6be2706bdbd4560

commit r15-1292-g7fed7e9bbc57d502e141e079a6be2706bdbd4560
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Jun 13 10:02:43 2024 -0400

    c++: ICE w/ ambig and non-strictly-viable cands [PR115239]

    Here during overload resolution we have two strictly viable ambiguous
    candidates #1 and #2, and two non-strictly viable candidates #3 and #4
    which we hold on to ever since r14-6522.  These latter candidates have
    an empty second arg conversion since the first arg conversion was deemed
    bad, and this trips up joust when called on #3 and #4 which assumes all
    arg conversions are there.

    We can fix this by making joust robust to empty arg conversions, but in
    this situation we shouldn't need to compare #3 and #4 at all given that
    we have a strictly viable candidate.  To that end, this patch makes
    tourney shortcut considering non-strictly viable candidates upon
    encountering ambiguity between two strictly viable candidates (taking
    advantage of the fact that the candidates list is sorted according to
    viability via splice_viable).

            PR c++/115239

    gcc/cp/ChangeLog:

            * call.cc (tourney): Don't consider a non-strictly viable
            candidate as the champ if there was ambiguity between two
            strictly viable candidates.

    gcc/testsuite/ChangeLog:

            * g++.dg/overload/error7.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>

[Bug c++/115239] [14 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
            Summary|[14/15 Regression] ICE:     |[14 Regression] ICE:
                   |Segmentation fault with     |Segmentation fault with
                   |ambiguous function call in  |ambiguous function call in
                   |some cases (`const char*`   |some cases (`const char*`
                   |vs `char` with `long` vs    |vs `char` with `long` vs
                   |`unsigned`) since r14-6522  |`unsigned`) since r14-6522
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org

[Bug c++/115239] [14 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:4df86402990e2f45e02a367f1734a22ebc041e98

commit r14-10319-g4df86402990e2f45e02a367f1734a22ebc041e98
Author: Patrick Palka <ppalka@redhat.com>
Date:   Thu Jun 13 10:02:43 2024 -0400

    c++: ICE w/ ambig and non-strictly-viable cands [PR115239]

    Here during overload resolution we have two strictly viable ambiguous
    candidates #1 and #2, and two non-strictly viable candidates #3 and #4
    which we hold on to ever since r14-6522.  These latter candidates have
    an empty second arg conversion since the first arg conversion was deemed
    bad, and this trips up joust when called on #3 and #4 which assumes all
    arg conversions are there.

    We can fix this by making joust robust to empty arg conversions, but in
    this situation we shouldn't need to compare #3 and #4 at all given that
    we have a strictly viable candidate.  To that end, this patch makes
    tourney shortcut considering non-strictly viable candidates upon
    encountering ambiguity between two strictly viable candidates (taking
    advantage of the fact that the candidates list is sorted according to
    viability via splice_viable).

            PR c++/115239

    gcc/cp/ChangeLog:

            * call.cc (tourney): Don't consider a non-strictly viable
            candidate as the champ if there was ambiguity between two
            strictly viable candidates.

    gcc/testsuite/ChangeLog:

            * g++.dg/overload/error7.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>
    (cherry picked from commit 7fed7e9bbc57d502e141e079a6be2706bdbd4560)

[Bug c++/115239] [14 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Patrick Palka <ppalka at gcc dot gnu.org> changed:

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

--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 14.2, thanks for the bug report.

[Bug c++/115239] [14 Regression] ICE: Segmentation fault with ambiguous function call in some cases (`const char*` vs `char` with `long` vs `unsigned`) since r14-6522

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115239

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jan.zizka at nokia dot com

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 115621 has been marked as a duplicate of this bug. ***