On Mon, Sep 5, 2016 at 7:26 AM, Kugan Vivekanandarajah <kugan.vivekanandara...@linaro.org> wrote: > Hi All, > > While looking at gcc source, I noticed that we are iterating over SSA > variable from 0 to num_ssa_names in some cases and 1 to num_ssa_names > in others. It seems that variable 0 is always NULL TREE.
Yeah, that's artificial because we don't assign SSA name version 0 (for some unknown reason). > But it can > confuse people who are looking for the first time. Therefore It might > be good to follow some consistent usage here. > > It might be also good to gave a FOR_EACH_SSAVAR iterator as we do in > other case. Here is attempt to do this based on what is done in other > places. Bootstrapped and regression tested on X86_64-linux-gnu with no > new regressions. is this OK? First of all some bikeshedding - FOR_EACH_SSA_NAME would be better as SSAVAR might be confused with iterating over SSA_NAME_VAR. Then, if you add an iterator why leave the name == NULL handling to consumers? That looks odd. Then, SSA names are just in a vector thus why not re-use the vector iterator? That is, #define FOR_EACH_SSA_NAME (name) \ for (unsigned i = 1; SSANAMES (cfun).iterate (i, &name); ++i) would be equivalent to your patch? Please also don't add new iterators that implicitely use 'cfun' but always use one that passes it as explicit arg. Thanks, Richard. > Thanks, > Kugan > > > gcc/ChangeLog: > > 2016-09-05 Kugan Vivekanandarajah <kug...@linaro.org> > > * tree-ssanames.h (ssa_iterator::ssa_iterator): New. > (ssa_iterator::get): Likewise. > (ssa_iterator::next): Likewise. > (FOR_EACH_SSAVAR): Likewise. > * cfgexpand.c (update_alias_info_with_stack_vars): Use > FOR_EACH_SSAVAR to iterate over SSA variables. > (pass_expand::execute): Likewise. > * omp-simd-clone.c (ipa_simd_modify_function_body): Likewise. > * tree-cfg.c (dump_function_to_file): Likewise. > * tree-into-ssa.c (pass_build_ssa::execute): Likewise. > (update_ssa): Likewise. > * tree-ssa-alias.c (dump_alias_info): Likewise. > * tree-ssa-ccp.c (ccp_finalize): Likewise. > * tree-ssa-coalesce.c (build_ssa_conflict_graph): Likewise. > (create_outofssa_var_map): Likewise. > (coalesce_ssa_name): Likewise. > * tree-ssa-operands.c (dump_immediate_uses): Likewise. > * tree-ssa-pre.c (compute_avail): Likewise. > * tree-ssa-sccvn.c (init_scc_vn): Likewise. > (scc_vn_restore_ssa_info): Likewise. > (free_scc_vn): Likwise. > (run_scc_vn): Likewise. > * tree-ssa-structalias.c (compute_points_to_sets): Likewise. > * tree-ssa-ter.c (new_temp_expr_table): Likewise.
