http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60291
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |compile-time-hog
Status|UNCONFIRMED |NEW
Last reconfirmed| |2014-02-20
Ever confirmed|0 |1
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.(In reply to Markus Trippelsdorf from comment #3)
> Perf shows:
>
> 24.26% cc1 cc1 [.] bitmap_set_bit(bitmap_head*, int)
> 20.88% cc1 cc1 [.] mark_all_vars_used_1(tree_node**, int*, void*)
/* Only need to mark VAR_DECLS; parameters and return results are not
eliminated as unused. */
if (TREE_CODE (t) == VAR_DECL)
{
/* When a global var becomes used for the first time also walk its
initializer (non global ones don't have any). */
if (set_is_used (t) && is_global_var (t))
mark_all_vars_used (&DECL_INITIAL (t));
not sure why we do that .... (we've had such compile-time-hog in former
referenced-vars tracking as well). That's quadratic if you refer to
a large global from all functions.
> 14.18% cc1 cc1 [.] operand_equal_p(tree_node const*, tree_node const*,...
> 9.15% cc1 cc1 [.] mem_attrs_eq_p(mem_attrs const*, mem_attrs const*)
> 4.17% cc1 cc1 [.] walk_tree_1(tree_node**, tree_node*
> (*)(tree_node**,...
> 1.69% cc1 cc1 [.] tree_block(tree_node*)
