Re: Timing information for CFG manipulations

[Brad Lucier <lucier@math.purdue.edu>]

> 
> 
> Hi,
> this patch should track down the second problem:
> 
> >  flow 2                : 267.66 (34%) usr 251.44 (98%) sys 519.08 (49%) wall
> >  32.36    602.16   253.66     9556    26.54    26.54  sbitmap_vector_alloc
> 
> It makes find_sub_basic_blocks to operate at bitmap of blocks, instead of just
> one and thus it avoids multiple initializations of edge cache structure.
> 
> The possible problem is that I now need to benerate bitmap when calling from
> recog.c.  I hope it won't cause perofrmance regression as the bitmap is
> relativly small (compared to edge cache).  If it will, I can use bitmap,
> instead of sbitmap, that will add some overhead at split_all_insns side.
> 
> I don't have time to finish bootstrap, but the patch appears to work.
> OK assuming the bootstrapping/regtesting i386 passes fluently?

Bootstrapped and regtested on i686-pc-linux-gnu, flow2 is now

 flow 2                :  33.92 (16%) usr   0.10 ( 2%) sys  34.00 (16%) wall

So, two home runs in one day!  (Two goals in one day? ...)

Here are the new timing details:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  ms/call  ms/call  name
 16.66     29.10    29.10 72698858     0.00     0.00  bitmap_operation
 12.43     50.81    21.71       13  1670.00  4145.64  calculate_global_regs_live
  9.86     68.04    17.23  9305997     0.00     0.00  cached_make_edge
  5.57     77.77     9.73    67331     0.14     0.38  try_crossjump_bb
  4.03     84.81     7.04                             htab_traverse
  2.99     90.03     5.22    27855     0.19     0.19  sbitmap_intersection_of_su
ccs

Brad