------- Comment #5 from rakdver at gcc dot gnu dot org 2009-06-20 17:08 ------- (In reply to comment #4) > With MAX_DOMINATORS_TO_WALK zero and find_loop_niter_by_eval completely > disabled > (checking enabled compiler, built with -O0): > > tree iv optimization : 11.12 ( 6%) usr 0.07 ( 5%) sys 12.02 ( 6%) wall > 59123 kB (20%) ggc > > With just find_loop_niter_by_eval disabled: > > tree iv optimization : 10.81 ( 6%) usr 0.05 ( 3%) sys 11.44 ( 6%) wall > 59123 kB (20%) ggc > > so that's it.
I assume you were really looking at tree canonical iv counter, not on the tree iv optimization one, otherwise I don't see how you got to this conclusion. > Zdenek - if for one exit we cannot determine the number of executions, > shouldn't we return chrec_dont_know here instead of just examining the > other exits? Why should we? The fact that we cannot determine number of iterations before a particular exit is taken does not tell you anything about the rest of the exits. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38729
