------- Comment #22 from rguenth at gcc dot gnu dot org 2008-01-07 15:56
-------
A histogram over the number of VUSEs/VDEFs that are being sorted by sort_vuses
reveals:
180 2
281964 256
1498 4
that is, we call qsort 281964 times with 256 virtual operands in the VEC. Now,
curiously(?), virtual operands are sorted already, but after DECL_UID, not
SSA_NAME_VERSION (see operand_build_sort_virtual).
Adjusting the tree-vn sorting order to that of the operand scanner lets us
improve these numbers to
27 2
28665 256
128 4
a reduction of a factor of 10. Profile after that:
Each sample counts as 0.01 seconds.
% cumulative self self total
time seconds seconds calls s/call s/call name
10.37 2.91 2.91 14769893 0.00 0.00 add_vars_for_offset
7.91 5.13 2.22 44264182 0.00 0.00 add_virtual_operand
7.16 7.14 2.01 235231611 0.00 0.00 var_ann
5.24 8.61 1.47 206399974 0.00 0.00 VN_INFO
5.20 10.07 1.46 172 0.01 0.04 DFS
5.17 11.52 1.45 68814811 0.00 0.00 iterative_hash_expr
4.92 12.90 1.38 12610 0.00 0.00 get_call_expr_operands
4.74 14.23 1.33 1439173 0.00 0.00 ggc_alloc_stat
4.63 15.53 1.30 69275355 0.00 0.00 htab_find_with_hash
3.88 16.62 1.09 19029637 0.00 0.00 set_bb_for_stmt
3.56 17.62 1.00 266239 0.00 0.00 valueize_vuses
2.21 18.24 0.62 129473 0.00 0.00 visit_reference_op_store
1.96 18.79 0.55 68703417 0.00 0.00 uid_decl_map_eq
1.92 19.33 0.54 operand_build_cmp
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34683
