https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91287
--- Comment #24 from Richard Biener <rguenth at gcc dot gnu.org> ---
Btw, this is controlled by symtab_node::output_to_lto_symbol_table_p which has
/* FIXME: Builtins corresponding to real functions probably should have
symbol table entries. */
if (TREE_CODE (decl) == FUNCTION_DECL && fndecl_built_in_p (decl))
return false;
we could try to do sth like
if (TREE_CODE (decl) == FUNCTION_DECL
&& (fndecl_built_in_p (decl, BUILT_IN_MD)
|| (fndecl_built_in_p (decl, BUILT_IN_NORMAL)
&& !associated_internal_fn (decl))))
return false;
but that would still leave us with too many undefineds I guess
(gcc_unreachable for one).
We do not currently track builtins that do have a library implementation
(whether that it is used in the end is another thing, but less important).
What we definitely can do is put a whitelist above like via the following
which also catches the case of definitions of builtins.
Index: gcc/symtab.c
===================================================================
--- gcc/symtab.c (revision 273968)
+++ gcc/symtab.c (working copy)
@@ -2375,10 +2375,24 @@ symtab_node::output_to_lto_symbol_table_
first place. */
if (VAR_P (decl) && DECL_HARD_REGISTER (decl))
return false;
+
/* FIXME: Builtins corresponding to real functions probably should have
symbol table entries. */
- if (TREE_CODE (decl) == FUNCTION_DECL && fndecl_built_in_p (decl))
- return false;
+ if (TREE_CODE (decl) == FUNCTION_DECL
+ && !definition
+ && fndecl_built_in_p (decl))
+ {
+ if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
+ switch (DECL_FUNCTION_CODE (decl))
+ {
+ CASE_FLT_FN (BUILT_IN_ATAN2):
+ CASE_FLT_FN (BUILT_IN_SIN):
+ return true;
+ default:
+ break;
+ }
+ return false;
+ }
/* We have real symbol that should be in symbol table. However try to trim
down the refernces to libraries bit more because linker will otherwise
