[Bug rtl-optimization/38518] Excessive compile time with -O3

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38518

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixing this DF issue get's us down to

 loop invariant motion   :   0.14 ( 0%) usr   0.01 ( 1%) sys   0.14 ( 0%) wall 
   148 kB ( 0%) ggc
 loop unswitching        :  15.44 (30%) usr   0.02 ( 3%) sys  15.48 (29%) wall 
     0 kB ( 0%) ggc
 TOTAL                 :  52.26             0.73            52.99            
456534 kB

so finally a RTL unswitching slowness ;)