[Bug bootstrap/52391] [4.7 regression] genattrtab almost 5X slower for m68k than in 4.6 and earlier releases

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52391

--- Comment #6 from Mikael Pettersson <mikpe at it dot uu.se> 2012-02-27 23:03:00 UTC ---
Top-most lines from gprof profile of genattrtab @ r178388:

Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls   s/call   s/call  name    
 67.71    437.11   437.11 138244364     0.00     0.00  simplify_and_tree
 22.16    580.15   143.04 532054774     0.00     0.00  attr_equal_p
  6.49    622.06    41.91 1753529513     0.00     0.00  rtx_equal_p
  2.23    636.47    14.41 78398171     0.00     0.00  simplify_or_tree
  0.99    642.88     6.41  2169340     0.00     0.00  simplify_test_exp
  0.24    644.41     1.53 15087810     0.00     0.00  compute_alternative_mask
  0.12    645.20     0.79  2105645     0.00     0.00  attr_rtx