https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101947
--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
It's the DW_AT_byte_size expression in:
(gdb) p debug_dwarf_die (die)
DIE 1041: DW_TAG_structure_type (0x7ffff39f06e0)
abbrev id: 51 offset: 1041 mark: 1
DW_AT_name: "exp_dist__rpc_target"
DW_AT_byte_size: location descriptor:
(0x7ffff39f0dc0) DW_OP_push_object_address 0, 0
(0x7ffff39f0e10) DW_OP_deref_type 4, die -> 0 (0x7ffff39f0af0)
(0x7ffff39f0e60) DW_OP_convert 0, 0
(0x7ffff39f0eb0) DW_OP_call4 die -> 0 (0x7ffff39f0a50), 0
(0x7ffff39f0f50) DW_OP_plus_uconst 7, 0
(0x7ffff39f0fa0) DW_OP_const1s 18446744073709551612, 0
(0x7ffff39f0960) DW_OP_and 0, 0
whose DW_OP_deref_type 4 operation uses:
DIE 0: DW_TAG_base_type (0x7ffff39f0af0)
abbrev id: 21 offset: 0 mark: 1
DW_AT_byte_size: 4
DW_AT_encoding: 5
DW_AT_name: "SIGNED_32"
DW_AT_artificial: 1
that was not initially referenced anywhere.