[Bug middle-end/15345] [3.4 Regression] [non-unit-at-a-time] unreferenced nested inline functions not optimized away

["jh at suse dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

------- Additional Comments From jh at suse dot cz  2004-07-19 15:43 -------
Subject: Re:  [3.4 Regression] [non-unit-at-a-time] unreferenced nested inline functions not optimized away

> 
> ------- Additional Comments From jakub at gcc dot gnu dot org  2004-07-19 14:11 -------
> This bug is IMHO very severe, it makes GCC 3.4.x totally unusable for glibc
> builds as it almost doubles the size of the dynamic linker.
> Can't this decision be reconsidered?

Why exactly does glibc rely on elliminating unused nested functions?
> 
> It worked just fine until GCC 3.3.x because of the DECL_DEFER_OUTPUT setting
> in rest_of_compilation (now rest_of_handle_inlining).
> 
> I have played with:
> --- gcc/toplev.c.jj        2004-02-20 19:37:45.000000000 +0100
> +++ gcc/toplev.c    2004-07-19 15:50:30.985366840 +0200
> @@ -2714,9 +2714,13 @@ rest_of_handle_inlining (tree decl)
>              for unreferenced symbols.  See g77.f-torture/execute/980520-1.f.
>              But removing this line from the check breaks all languages that
>              use the call graph to output symbols.  This hard-coded check is
> -            the least invasive work-around.  */
> +            the least invasive work-around.
> +            C nested functions need to be deferred here too, otherwise
> +            they will be emitted even when never used.  */
>           && (flag_inline_functions
> -             || strcmp (lang_hooks.name, "GNU F77") == 0)
> +             || strcmp (lang_hooks.name, "GNU F77") == 0
> +             || (strcmp (lang_hooks.name, "GNU C") == 0
> +                 && DECL_CONTEXT (decl)))
>           && ((! TREE_PUBLIC (decl) && ! TREE_ADDRESSABLE (decl)
>                && ! TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))
>                && ! flag_keep_inline_functions)
> 
> Honza, can you see what problems could this cause?

That might work (using the old deffering code path just didn't occured
to me).  Instead of relying on the hooks, I think we might simply use
cgraph_node (decl)->origin test so we won't mess up for methods (this is
why you need the checks for languages, right?)

Thanks!
Honza
> 
> -- 
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15345
> 
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15345