https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77848
--- Comment #11 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- (In reply to rguent...@suse.de from comment #10) > On Fri, 4 Nov 2016, wschmidt at gcc dot gnu.org wrote: > > > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77848 > > > > --- Comment #8 from Bill Schmidt <wschmidt at gcc dot gnu.org> --- > > FYI, the patch I am testing is: > > > > Index: gcc/tree-if-conv.c > > =================================================================== > > --- gcc/tree-if-conv.c (revision 241802) > > +++ gcc/tree-if-conv.c (working copy) > > @@ -2767,8 +2767,7 @@ tree_if_conversion (struct loop *loop) > > || loop->dont_vectorize)) > > goto cleanup; > > > > - if ((any_pred_load_store || any_complicated_phi) > > - && !version_loop_for_if_conversion (loop)) > > + if (flag_tree_loop_vectorize && !version_loop_for_if_conversion (loop)) > > goto cleanup; > > can any_pred_load_store or any_complicated_phi never be true without > flag_tree_loop_vectorize? It's quite possible, I'm not sure. I was trying to remove all preconditions for doing if-conversion, but without the test for flag_tree_loop_vectorize I ran into failures in the test suite for -O2 -ftree-if-conversion or whatever it is. > > Btw, I think we should simply guard if-conversion with > flag_tree_loop_vectorize... (given it has no cost model) Seems that can work if we can make SLP vectorization handle the PHI-convertibles on its own without if-conversion, as you suggested, but until then it will lose some SLP opportunities. By the way, outer loop vectorization is failing because of if ((loop->inner)->inner || (loop->inner)->next) { if (dump_enabled_p ()) dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location, "not vectorized: multiple nested loops.\n"); return false; } The versioned inner loop has two loops, so we don't even consider it further. Bill > > Richard. > > > /* Now all statements are if-convertible. Combine all the basic > > > >
