https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93384
--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, it seems
#0 symtab_node::noninterposable_alias (this=<optimized out>) at
../../gcc/symtab.c:1878
#1 0x0000000010f6e5a0 in function_and_variable_visibility
(whole_program=<optimized out>) at ../../gcc/ipa-visibility.c:772
#2 0x00000000111d1ff4 in (anonymous
namespace)::whole_program_function_and_variable_visibility () at
../../gcc/ipa-visibility.c:969
#3 (anonymous namespace)::pass_ipa_whole_program_visibility::execute
(this=<optimized out>) at ../../gcc/ipa-visibility.c:969
#4 0x00000000109f38c4 in execute_one_pass (pass=pass@entry=0x11896850) at
../../gcc/passes.c:2500
#5 0x00000000109f3578 in execute_ipa_pass_list (pass=0x11896850) at
../../gcc/passes.c:2927
#6 0x0000000011057524 in ipa_passes () at ../../gcc/cgraphunit.c:2660
#7 symbol_table::compile (this=0x7ffff5a30000) at ../../gcc/cgraphunit.c:2737
#8 0x000000001102c318 in lto_main () at ../../gcc/lto/lto.c:658
#9 0x00000000110e7838 in compile_file () at ../../gcc/toplev.c:459
#10 0x000000001073b6fc in do_compile () at ../../gcc/toplev.c:2274
#11 toplev::main (this=0x7fffffffdd76, argc=<optimized out>, argv=<optimized
out>) at ../../gcc/toplev.c:2413
#12 0x000000001073de34 in main (argc=<optimized out>, argv=0x7fffffffe1a8) at
../../gcc/main.c:39
is called just once in lto1 for the _PyObject_AssertFailed node, so my guess is
that it has been previously created in cc1plus and streamed out and in.
The reason why
node->call_for_symbol_and_aliases (symtab_node::noninterposable_alias,
(void *)&new_node, true);
doesn't find the already existing alias is that while _PyObject_AssertFailed
and
_PyObject_AssertFailed.localalias have the same TREE_TYPE, DECL_CONTEXT and
DECL_ATTRIBUTES, the _PyObject_AssertFailed node has TREE_THIS_VOLATILE set on
it, while the alias doesn't, so flags_from_type_or_decl (node->decl) returns 0,
while flags_from_type_or_decl (fn->decl) returns ECF_NORETURN.
During symtab_node::noninterposable_alias (void) it uses copy_node and so
should copy even TREE_THIS_VOLATILE, so my guess is that the function isn't
marked noreturn explicitly, but it was later on that ipa-pure-const or whatever
determined the function is noreturn, and didn't update the aliases (I guess
such updating would be dangerous).
