From e41ba804ba5f5ca433e09238d561b1b4c8b10985 Mon Sep 17 00:00:00 2001 From: Kewen Lin Date: Thu, 29 Jul 2021 22:26:25 -0500 Subject: Use range-based for loops for traversing loops This patch follows Martin's suggestion here[1], to support range based loop for iterating loops, analogously to the patch for vec[2]. For example, use below range-based for loop for (auto loop : loops_list (cfun, 0)) to replace the previous macro FOR_EACH_LOOP FOR_EACH_LOOP (loop, 0) [1] https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573424.html [2] https://gcc.gnu.org/pipermail/gcc-patches/2021-June/572315.html gcc/ChangeLog: * cfgloop.h (as_const): New function. (class loop_iterator): Rename to ... (class loops_list): ... this. (loop_iterator::next): Rename to ... (loops_list::Iter::fill_curr_loop): ... this and adjust. (loop_iterator::loop_iterator): Rename to ... (loops_list::loops_list): ... this and adjust. (loops_list::Iter): New class. (loops_list::iterator): New type. (loops_list::const_iterator): New type. (loops_list::begin): New function. (loops_list::end): Likewise. (loops_list::begin const): Likewise. (loops_list::end const): Likewise. (FOR_EACH_LOOP): Remove. (FOR_EACH_LOOP_FN): Remove. * cfgloop.c (flow_loops_dump): Adjust FOR_EACH_LOOP* with range-based for loop with loops_list instance. (sort_sibling_loops): Likewise. (disambiguate_loops_with_multiple_latches): Likewise. (verify_loop_structure): Likewise. * cfgloopmanip.c (create_preheaders): Likewise. (force_single_succ_latches): Likewise. * config/aarch64/falkor-tag-collision-avoidance.c (execute_tag_collision_avoidance): Likewise. * config/mn10300/mn10300.c (mn10300_scan_for_setlb_lcc): Likewise. * config/s390/s390.c (s390_adjust_loops): Likewise. * doc/loop.texi: Likewise. * gimple-loop-interchange.cc (pass_linterchange::execute): Likewise. * gimple-loop-jam.c (tree_loop_unroll_and_jam): Likewise. * gimple-loop-versioning.cc (loop_versioning::analyze_blocks): Likewise. (loop_versioning::make_versioning_decisions): Likewise. * gimple-ssa-split-paths.c (split_paths): Likewise. * graphite-isl-ast-to-gimple.c (graphite_regenerate_ast_isl): Likewise. * graphite.c (canonicalize_loop_form): Likewise. (graphite_transform_loops): Likewise. * ipa-fnsummary.c (analyze_function_body): Likewise. * ipa-pure-const.c (analyze_function): Likewise. * loop-doloop.c (doloop_optimize_loops): Likewise. * loop-init.c (loop_optimizer_finalize): Likewise. (fix_loop_structure): Likewise. * loop-invariant.c (calculate_loop_reg_pressure): Likewise. (move_loop_invariants): Likewise. * loop-unroll.c (decide_unrolling): Likewise. (unroll_loops): Likewise. * modulo-sched.c (sms_schedule): Likewise. * predict.c (predict_loops): Likewise. (pass_profile::execute): Likewise. * profile.c (branch_prob): Likewise. * sel-sched-ir.c (sel_finish_pipelining): Likewise. (sel_find_rgns): Likewise. * tree-cfg.c (replace_loop_annotate): Likewise. (replace_uses_by): Likewise. (move_sese_region_to_fn): Likewise. * tree-if-conv.c (pass_if_conversion::execute): Likewise. * tree-loop-distribution.c (loop_distribution::execute): Likewise. * tree-parloops.c (parallelize_loops): Likewise. * tree-predcom.c (tree_predictive_commoning): Likewise. * tree-scalar-evolution.c (scev_initialize): Likewise. (scev_reset): Likewise. * tree-ssa-dce.c (find_obviously_necessary_stmts): Likewise. * tree-ssa-live.c (remove_unused_locals): Likewise. * tree-ssa-loop-ch.c (ch_base::copy_headers): Likewise. * tree-ssa-loop-im.c (analyze_memory_references): Likewise. (tree_ssa_lim_initialize): Likewise. * tree-ssa-loop-ivcanon.c (canonicalize_induction_variables): Likewise. * tree-ssa-loop-ivopts.c (tree_ssa_iv_optimize): Likewise. * tree-ssa-loop-manip.c (get_loops_exits): Likewise. * tree-ssa-loop-niter.c (estimate_numbers_of_iterations): Likewise. (free_numbers_of_iterations_estimates): Likewise. * tree-ssa-loop-prefetch.c (tree_ssa_prefetch_arrays): Likewise. * tree-ssa-loop-split.c (tree_ssa_split_loops): Likewise. * tree-ssa-loop-unswitch.c (tree_ssa_unswitch_loops): Likewise. * tree-ssa-loop.c (gate_oacc_kernels): Likewise. (pass_scev_cprop::execute): Likewise. * tree-ssa-propagate.c (clean_up_loop_closed_phi): Likewise. * tree-ssa-sccvn.c (do_rpo_vn): Likewise. * tree-ssa-threadupdate.c (jump_thread_path_registry::thread_through_all_blocks): Likewise. * tree-vectorizer.c (vectorize_loops): Likewise. * tree-vrp.c (vrp_asserts::find_assert_locations): Likewise. --- gcc/tree-ssa-loop.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'gcc/tree-ssa-loop.c') diff --git a/gcc/tree-ssa-loop.c b/gcc/tree-ssa-loop.c index 957ac0f..0cc4b3b 100644 --- a/gcc/tree-ssa-loop.c +++ b/gcc/tree-ssa-loop.c @@ -157,8 +157,7 @@ gate_oacc_kernels (function *fn) if (!lookup_attribute ("oacc kernels", DECL_ATTRIBUTES (fn->decl))) return false; - class loop *loop; - FOR_EACH_LOOP (loop, 0) + for (auto loop : loops_list (cfun, 0)) if (loop->in_oacc_kernels_region) return true; @@ -455,12 +454,11 @@ public: unsigned pass_scev_cprop::execute (function *) { - class loop *loop; bool any = false; /* Perform final value replacement in loops, in case the replacement expressions are cheap. */ - FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) + for (auto loop : loops_list (cfun, LI_FROM_INNERMOST)) any |= final_value_replacement_loop (loop); return any ? TODO_cleanup_cfg | TODO_update_ssa_only_virtuals : 0; -- cgit v1.1 From 01b5038718056b024b370b74a874fbd92c5bbab3 Mon Sep 17 00:00:00 2001 From: Aldy Hernandez Date: Thu, 9 Sep 2021 20:30:28 +0200 Subject: Disable threading through latches until after loop optimizations. The motivation for this patch was enabling the use of global ranges in the path solver, but this caused certain properties of loops being destroyed which made subsequent loop optimizations to fail. Consequently, this patch's mail goal is to disable jump threading involving the latch until after loop optimizations have run. As can be seen in the test adjustments, we mostly shift the threading from the early threaders (ethread, thread[12] to the late threaders thread[34]). I have nuked some of the early notes in the testcases that came as part of the jump threader rewrite. They're mostly noise now. Note that we could probably relax some other restrictions in profitable_path_p when loop optimizations have completed, but it would require more testing, and I'm hesitant to touch more things than needed at this point. I have added a reminder to the function to keep this in mind. Finally, perhaps as a follow-up, we should apply the same restrictions to the forward threader. At some point I'd like to combine the cost models. Tested on x86-64 Linux. p.s. There is a thorough discussion involving the limitations of jump threading involving loops here: https://gcc.gnu.org/pipermail/gcc/2021-September/237247.html gcc/ChangeLog: * tree-pass.h (PROP_loop_opts_done): New. * gimple-range-path.cc (path_range_query::internal_range_of_expr): Intersect with global range. * tree-ssa-loop.c (tree_ssa_loop_done): Set PROP_loop_opts_done. * tree-ssa-threadbackward.c (back_threader_profitability::profitable_path_p): Disable threading through latches until after loop optimizations have run. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/ssa-dom-thread-2b.c: Adjust for disabling of threading through latches. * gcc.dg/tree-ssa/ssa-dom-thread-6.c: Same. * gcc.dg/tree-ssa/ssa-dom-thread-7.c: Same. Co-authored-by: Michael Matz --- gcc/tree-ssa-loop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'gcc/tree-ssa-loop.c') diff --git a/gcc/tree-ssa-loop.c b/gcc/tree-ssa-loop.c index 0cc4b3b..1bbf2f1 100644 --- a/gcc/tree-ssa-loop.c +++ b/gcc/tree-ssa-loop.c @@ -540,7 +540,7 @@ const pass_data pass_data_tree_loop_done = OPTGROUP_LOOP, /* optinfo_flags */ TV_NONE, /* tv_id */ PROP_cfg, /* properties_required */ - 0, /* properties_provided */ + PROP_loop_opts_done, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_cleanup_cfg, /* todo_flags_finish */ -- cgit v1.1