https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108183
--- Comment #1 from Iain Sandoe <iains at gcc dot gnu.org> ---
example:
a-hello.s:217:2: error: symbol '__M2_termios_ctor' can not be undefined in a
subtraction expression
leal __M2_termios_ctor-L5$pb(%eax), %edx #, _T53_57
(lldb) p (void) debug_tree(decl)
<function_decl 0x1068c5100 _M2_termios_ctor
type <function_type 0x106829dc8
type <void_type 0x1068250a8 PROC VOID
align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x1068250a8
pointer_to_this <pointer_type 0x106825150 ADDRESS>>
QI
size <integer_cst 0x106802d98 constant 8>
unit-size <integer_cst 0x106802db0 constant 1>
align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x106829dc8
arg-types <tree_list 0x10681cde8 value <void_type 0x1068250a8 PROC>>
pointer_to_this <pointer_type 0x106850dc8>>
addressable public static QI (null):0:0 align:8 warn_if_not_align:0 context
<translation_unit_decl 0x10680d168 D.46>
(mem:QI (symbol_ref:SI ("_M2_termios_ctor") <function_decl 0x1068c5100
_M2_termios_ctor>) [0 S1 A8]) chain <function_decl 0x1068c5000 _M2_RTco_fini>>
