[Bug c/60291] slow compile times for any mode (-O0/-O1/-O2) on large .c source file (30MBs)

[trippels at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60291

--- Comment #3 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
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*)
 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*)