cgraph_remove_node slow(?)

[Richard Guenther <rguenth at tat dot physik dot uni-tuebingen dot de>]

Hi!

I'm seeing from a flat profile of cc1plus compiling the tramp3d-v3
testcase with leafification enabled (aka lots of inlining):

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls   s/call   s/call  name
  3.63      5.07     5.07   163579     0.00     0.00  cgraph_remove_node
  2.74      8.90     3.83 44552296     0.00     0.00  ggc_alloc_stat
  2.49     12.37     3.47   381067     0.00     0.00  cgraph_remove_edge
  1.68     14.72     2.35    13314     0.00     0.00  compute_immediate_uses
  1.52     16.84     2.12 56272844     0.00     0.00  bitmap_set_bit
  1.50     18.93     2.09 54900205     0.00     0.00  ggc_set_mark

where cgraph_remove_node is called like:

                0.01    0.01     266/163579      cgraph_optimize [4]
                0.22    0.14    7117/163579      cgraph_finalize_compilation_unit [316]
                4.84    3.02  156196/163579      expand_calls_inline [18]
[24]     5.9    5.07    3.16  163579         cgraph_remove_node [24]
                3.10    0.00  340261/381067      cgraph_remove_edge [52]
                0.03    0.03  163579/111937201     htab_find_slot <cycle 2> [276]
                0.00    0.00   14716/169400      htab_clear_slot [3363]
                0.00    0.00   14970/161941      dump_enabled_p [3550]

Is there some low-hanging fruit to optimize the cgraph_remove_node
calls from expand_call_inline (I didn't see anything obvious)?

Thanks,
Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/