https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111401
--- Comment #4 from rguenther at suse dot de <rguenther at suse dot de> --- On Wed, 13 Sep 2023, rdapp at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111401 > > Robin Dapp <rdapp at gcc dot gnu.org> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |rdapp at gcc dot gnu.org > > --- Comment #2 from Robin Dapp <rdapp at gcc dot gnu.org> --- > I played around with this a bit. Emitting a COND_LEN in if-convert is easy: > > _ifc__35 = .COND_ADD (_23, init_20, _8, init_20); > > However, during reduction handling we rely on the reduction being a gimple > assign and binary operation, though so I needed to fix some places and indices > as well as the proper mask. > > What complicates things a bit is that we assume that "init_20" (i.e. the > reduction def) occurs once when we have it twice in the COND_ADD. I just > special cased that for now. Is this the proper thing to do? I think so - we should ignore a use in the else value when the other use is in that same stmt. > diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc > index 23c6e8259e7..e99add3cf16 100644 > --- a/gcc/tree-vect-loop.cc > +++ b/gcc/tree-vect-loop.cc > @@ -3672,7 +3672,7 @@ vect_analyze_loop (class loop *loop, vec_info_shared > *shared) > static bool > fold_left_reduction_fn (code_helper code, internal_fn *reduc_fn) > { > - if (code == PLUS_EXPR) > + if (code == PLUS_EXPR || code == IFN_COND_ADD) > { > *reduc_fn = IFN_FOLD_LEFT_PLUS; > return true; > @@ -4106,8 +4106,11 @@ vect_is_simple_reduction (loop_vec_info loop_info, > stmt_vec_info phi_info, > return NULL; > } > > - nphi_def_loop_uses++; > - phi_use_stmt = use_stmt; > + if (use_stmt != phi_use_stmt) > + { > + nphi_def_loop_uses++; > + phi_use_stmt = use_stmt; > + } > > @@ -7440,6 +7457,9 @@ vectorizable_reduction (loop_vec_info loop_vinfo, > if (i == STMT_VINFO_REDUC_IDX (stmt_info)) > continue; > > + if (op.ops[i] == op.ops[STMT_VINFO_REDUC_IDX (stmt_info)]) > + continue; > + > > Apart from that I think what's mainly missing is making the added code nicer. > Going to attach a tentative patch later. > >
