[Bug rtl-optimization/69609] block reordering consumes an inordinate amount of time, REE consumes much memory

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69609

--- Comment #16 from Richard Biener <rguenth at gcc dot gnu.org> ---
current HEAD with -O2 -fno-checking (a checking enabled build) shows

 callgraph ipa passes               :   6.80 ( 14%)   0.19 ( 12%)   7.00 ( 14%)
   33M (  5%)
 tree FRE                           :   6.55 ( 13%)   0.05 (  3%)   6.58 ( 13%)
 4146k (  1%)
 PRE                                :  13.08 ( 26%)   0.04 (  3%)  13.12 ( 26%)
   13k (  0%)
 machine dep reorg                  :   4.63 (  9%)   0.00 (  0%)   4.62 (  9%)
    0  (  0%)
 TOTAL                              :  49.61          1.55         51.18       
  706M

I looked at the tree FRE time and improved PHI hashing a bit but we still
spend a lot of time in processing PHIs.