[Bug c++/89405] [8/9 Regression] ICE in import_export_decl, at cp/decl2.c:2959

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89405

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dmalcolm at gcc dot gnu.org

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
-fno-weak: "This option exists only for testing, and should not be used by
end-users"

Failing assertion:

2957      /* Any code that creates entities with TREE_PUBLIC cleared should
2958         also set DECL_INTERFACE_KNOWN.  */
2959      gcc_assert (TREE_PUBLIC (decl));

on this decl:

(gdb) call debug_tree (decl)
 <var_decl 0x7ffff1a657e0 value
    type <boolean_type 0x7ffff1a72888 bool readonly unsigned type_6 QI
        size <integer_cst 0x7ffff18adf18 constant 8>
        unit-size <integer_cst 0x7ffff18adf30 constant 1>
        align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff1a72888 precision:1 min <integer_cst 0x7ffff18cf180 0> max <integer_cst
0x7ffff18cf1b0 1>>
    readonly constant used static tree_1 tree_2 tree_3 unsigned nonlocal
in_system_header read decl_1 QI
../x86_64-pc-linux-gnu/libstdc++-v3/include/type_traits:59:45 size <integer_cst
0x7ffff18adf18 8> unit-size <integer_cst 0x7ffff18adf30 1>
    align:8 warn_if_not_align:0 context <record_type 0x7ffff1a6ee70
integral_constant> initial <integer_cst 0x7ffff18cf180 0>
    template-info 0x7ffff1a69ba0 chain <function_decl 0x7ffff1a6d500 __conv_op
>>

(gdb) call inform (decl.decl_minimal.locus, "")
In file included from
../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/move.h:55,
                 from
../x86_64-pc-linux-gnu/libstdc++-v3/include/bits/nested_exception.h:40,
                 from ../../src/libstdc++-v3/libsupc++/exception:144,
                 from ../../src/libstdc++-v3/libsupc++/new:40,
                 from /tmp/test.cc:1:
../x86_64-pc-linux-gnu/libstdc++-v3/include/type_traits: At global scope:
../x86_64-pc-linux-gnu/libstdc++-v3/include/type_traits:59:45: note: 
   59 |       static constexpr _Tp                  value = __v;
      |                                             ^~~~~

within:

  /// integral_constant
  template<typename _Tp, _Tp __v>
    struct integral_constant
    {
      static constexpr _Tp                  value = __v;

The flag gets cleared here in maybe_commonize_var in the "else" suite of an "if
(flag_weak)":

5630                  /* While for initialized variables, we must use internal
5631                     linkage -- which means that multiple copies will not
5632                     be merged.  */
5633                  TREE_PUBLIC (decl) = 0;
5634                  DECL_COMMON (decl) = 0;