diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/tree-ssa-loop-unswitch.cc | 66 |
1 files changed, 54 insertions, 12 deletions
diff --git a/gcc/tree-ssa-loop-unswitch.cc b/gcc/tree-ssa-loop-unswitch.cc index 7d6781d..dfe75f5 100644 --- a/gcc/tree-ssa-loop-unswitch.cc +++ b/gcc/tree-ssa-loop-unswitch.cc @@ -118,6 +118,7 @@ struct unswitch_predicate if (!false_range.varying_p () && !false_range.undefined_p ()) false_range.invert (); + count = e->count (); num = predicates->length (); predicates->safe_push (this); } @@ -126,7 +127,8 @@ struct unswitch_predicate unswitch_predicate (gcond *stmt) : switch_p (false) { - if (EDGE_SUCC (gimple_bb (stmt), 0)->flags & EDGE_TRUE_VALUE) + basic_block bb = gimple_bb (stmt); + if (EDGE_SUCC (bb, 0)->flags & EDGE_TRUE_VALUE) edge_index = 0; else edge_index = 1; @@ -134,6 +136,7 @@ struct unswitch_predicate tree rhs = gimple_cond_rhs (stmt); enum tree_code code = gimple_cond_code (stmt); condition = build2 (code, boolean_type_node, lhs, rhs); + count = EDGE_SUCC (bb, 0)->count ().max (EDGE_SUCC (bb, 1)->count ()); if (irange::supports_p (TREE_TYPE (lhs))) { auto range_op = range_op_handler (code, TREE_TYPE (lhs)); @@ -180,6 +183,9 @@ struct unswitch_predicate /* Index of the edge the predicate belongs to in the successor vector. */ int edge_index; + /* The profile count of this predicate. */ + profile_count count; + /* Whether the predicate was created from a switch statement. */ bool switch_p; @@ -206,10 +212,14 @@ static class loop *tree_unswitch_loop (class loop *, edge, tree); static bool tree_unswitch_single_loop (class loop *, dump_user_location_t, predicate_vector &predicate_path, unsigned loop_size, unsigned &budget, - int ignored_edge_flag, bitmap); + int ignored_edge_flag, bitmap, + unswitch_predicate * = NULL, + basic_block = NULL); static void find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, - vec<unswitch_predicate *> &candidates); + vec<unswitch_predicate *> &candidates, + unswitch_predicate *&hottest, + basic_block &hottest_bb); static bool tree_unswitch_outer_loop (class loop *); static edge find_loop_guard (class loop *, vec<gimple *>&); static bool empty_bb_without_guard_p (class loop *, basic_block, @@ -242,7 +252,8 @@ set_predicates_for_bb (basic_block bb, vec<unswitch_predicate *> predicates) Return total number of instructions in the loop. */ static unsigned -init_loop_unswitch_info (class loop *loop) +init_loop_unswitch_info (class loop *loop, unswitch_predicate *&hottest, + basic_block &hottest_bb) { unsigned total_insns = 0; @@ -259,13 +270,16 @@ init_loop_unswitch_info (class loop *loop) total_insns += insns; } + hottest = NULL; + hottest_bb = NULL; /* Find all unswitching candidates. */ for (unsigned i = 0; i != loop->num_nodes; i++) { /* Find a bb to unswitch on. */ vec<unswitch_predicate *> candidates; candidates.create (1); - find_unswitching_predicates_for_bb (bbs[i], loop, candidates); + find_unswitching_predicates_for_bb (bbs[i], loop, candidates, + hottest, hottest_bb); if (!candidates.is_empty ()) set_predicates_for_bb (bbs[i], candidates); else @@ -329,7 +343,10 @@ tree_ssa_unswitch_loops (function *fun) unswitch_predicate::predicates = new vec<unswitch_predicate *> (); /* Unswitch innermost loop. */ - unsigned int loop_size = init_loop_unswitch_info (loop); + unswitch_predicate *hottest; + basic_block hottest_bb; + unsigned int loop_size = init_loop_unswitch_info (loop, hottest, + hottest_bb); unsigned int budget = loop_size + param_max_unswitch_insns; predicate_vector predicate_path; @@ -338,7 +355,8 @@ tree_ssa_unswitch_loops (function *fun) changed_unswitch |= tree_unswitch_single_loop (loop, loc, predicate_path, loop_size, budget, - ignored_edge_flag, handled); + ignored_edge_flag, handled, + hottest, hottest_bb); predicate_path.release (); for (auto predlist : bb_predicates) @@ -449,7 +467,9 @@ is_maybe_undefined (const tree name, gimple *stmt, class loop *loop) static void find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, - vec<unswitch_predicate *> &candidates) + vec<unswitch_predicate *> &candidates, + unswitch_predicate *&hottest, + basic_block &hottest_bb) { gimple *last, *def; tree use; @@ -489,6 +509,14 @@ find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, unswitch_predicate *predicate = new unswitch_predicate (stmt); candidates.safe_push (predicate); + /* If we unswitch on this predicate we isolate both paths, so + pick the highest count for updating of the hottest predicate + to unswitch on first. */ + if (!hottest || predicate->count > hottest->count) + { + hottest = predicate; + hottest_bb = bb; + } } else if (gswitch *stmt = safe_dyn_cast <gswitch *> (last)) { @@ -561,6 +589,11 @@ find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, edge_index, e, edge_range[edge_index]); candidates.safe_push (predicate); + if (!hottest || predicate->count > hottest->count) + { + hottest = predicate; + hottest_bb = bb; + } } } } @@ -888,13 +921,15 @@ evaluate_loop_insns_for_predicate (class loop *loop, /* Unswitch single LOOP. PREDICATE_PATH contains so far used predicates for unswitching. BUDGET is number of instruction for which we can increase - the loop and is updated when unswitching occurs. */ + the loop and is updated when unswitching occurs. If HOTTEST is not + NULL then pick this candidate as the one to unswitch on. */ static bool tree_unswitch_single_loop (class loop *loop, dump_user_location_t loc, predicate_vector &predicate_path, unsigned loop_size, unsigned &budget, - int ignored_edge_flag, bitmap handled) + int ignored_edge_flag, bitmap handled, + unswitch_predicate *hottest, basic_block hottest_bb) { class loop *nloop; bool changed = false; @@ -939,8 +974,15 @@ tree_unswitch_single_loop (class loop *loop, dump_user_location_t loc, } return false; }; - /* Check predicates of reachable blocks. */ - evaluate_bbs (loop, NULL, ignored_edge_flag, check_predicates); + + if (hottest) + { + predicate = hottest; + predicate_bb = hottest_bb; + } + else + /* Check predicates of reachable blocks. */ + evaluate_bbs (loop, NULL, ignored_edge_flag, check_predicates); if (predicate != NULL) { |