| /* Natural loop discovery code for GNU compiler. |
| Copyright (C) 2000-2017 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it under |
| the terms of the GNU General Public License as published by the Free |
| Software Foundation; either version 3, or (at your option) any later |
| version. |
| |
| GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "cfghooks.h" |
| #include "gimple-ssa.h" |
| #include "diagnostic-core.h" |
| #include "cfganal.h" |
| #include "cfgloop.h" |
| #include "gimple-iterator.h" |
| #include "dumpfile.h" |
| |
| static void flow_loops_cfg_dump (FILE *); |
| |
| /* Dump loop related CFG information. */ |
| |
| static void |
| flow_loops_cfg_dump (FILE *file) |
| { |
| basic_block bb; |
| |
| if (!file) |
| return; |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| edge succ; |
| edge_iterator ei; |
| |
| fprintf (file, ";; %d succs { ", bb->index); |
| FOR_EACH_EDGE (succ, ei, bb->succs) |
| fprintf (file, "%d ", succ->dest->index); |
| fprintf (file, "}\n"); |
| } |
| } |
| |
| /* Return nonzero if the nodes of LOOP are a subset of OUTER. */ |
| |
| bool |
| flow_loop_nested_p (const struct loop *outer, const struct loop *loop) |
| { |
| unsigned odepth = loop_depth (outer); |
| |
| return (loop_depth (loop) > odepth |
| && (*loop->superloops)[odepth] == outer); |
| } |
| |
| /* Returns the loop such that LOOP is nested DEPTH (indexed from zero) |
| loops within LOOP. */ |
| |
| struct loop * |
| superloop_at_depth (struct loop *loop, unsigned depth) |
| { |
| unsigned ldepth = loop_depth (loop); |
| |
| gcc_assert (depth <= ldepth); |
| |
| if (depth == ldepth) |
| return loop; |
| |
| return (*loop->superloops)[depth]; |
| } |
| |
| /* Returns the list of the latch edges of LOOP. */ |
| |
| static vec<edge> |
| get_loop_latch_edges (const struct loop *loop) |
| { |
| edge_iterator ei; |
| edge e; |
| vec<edge> ret = vNULL; |
| |
| FOR_EACH_EDGE (e, ei, loop->header->preds) |
| { |
| if (dominated_by_p (CDI_DOMINATORS, e->src, loop->header)) |
| ret.safe_push (e); |
| } |
| |
| return ret; |
| } |
| |
| /* Dump the loop information specified by LOOP to the stream FILE |
| using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
| |
| void |
| flow_loop_dump (const struct loop *loop, FILE *file, |
| void (*loop_dump_aux) (const struct loop *, FILE *, int), |
| int verbose) |
| { |
| basic_block *bbs; |
| unsigned i; |
| vec<edge> latches; |
| edge e; |
| |
| if (! loop || ! loop->header) |
| return; |
| |
| fprintf (file, ";;\n;; Loop %d\n", loop->num); |
| |
| fprintf (file, ";; header %d, ", loop->header->index); |
| if (loop->latch) |
| fprintf (file, "latch %d\n", loop->latch->index); |
| else |
| { |
| fprintf (file, "multiple latches:"); |
| latches = get_loop_latch_edges (loop); |
| FOR_EACH_VEC_ELT (latches, i, e) |
| fprintf (file, " %d", e->src->index); |
| latches.release (); |
| fprintf (file, "\n"); |
| } |
| |
| fprintf (file, ";; depth %d, outer %ld\n", |
| loop_depth (loop), (long) (loop_outer (loop) |
| ? loop_outer (loop)->num : -1)); |
| |
| if (loop->latch) |
| { |
| bool read_profile_p; |
| gcov_type nit = expected_loop_iterations_unbounded (loop, &read_profile_p); |
| if (read_profile_p && !loop->any_estimate) |
| fprintf (file, ";; profile-based iteration count: %" PRIu64 "\n", |
| (uint64_t) nit); |
| } |
| |
| fprintf (file, ";; nodes:"); |
| bbs = get_loop_body (loop); |
| for (i = 0; i < loop->num_nodes; i++) |
| fprintf (file, " %d", bbs[i]->index); |
| free (bbs); |
| fprintf (file, "\n"); |
| |
| if (loop_dump_aux) |
| loop_dump_aux (loop, file, verbose); |
| } |
| |
| /* Dump the loop information about loops to the stream FILE, |
| using auxiliary dump callback function LOOP_DUMP_AUX if non null. */ |
| |
| void |
| flow_loops_dump (FILE *file, void (*loop_dump_aux) (const struct loop *, FILE *, int), int verbose) |
| { |
| struct loop *loop; |
| |
| if (!current_loops || ! file) |
| return; |
| |
| fprintf (file, ";; %d loops found\n", number_of_loops (cfun)); |
| |
| FOR_EACH_LOOP (loop, LI_INCLUDE_ROOT) |
| { |
| flow_loop_dump (loop, file, loop_dump_aux, verbose); |
| } |
| |
| if (verbose) |
| flow_loops_cfg_dump (file); |
| } |
| |
| /* Free data allocated for LOOP. */ |
| |
| void |
| flow_loop_free (struct loop *loop) |
| { |
| struct loop_exit *exit, *next; |
| |
| vec_free (loop->superloops); |
| |
| /* Break the list of the loop exit records. They will be freed when the |
| corresponding edge is rescanned or removed, and this avoids |
| accessing the (already released) head of the list stored in the |
| loop structure. */ |
| for (exit = loop->exits->next; exit != loop->exits; exit = next) |
| { |
| next = exit->next; |
| exit->next = exit; |
| exit->prev = exit; |
| } |
| |
| ggc_free (loop->exits); |
| ggc_free (loop); |
| } |
| |
| /* Free all the memory allocated for LOOPS. */ |
| |
| void |
| flow_loops_free (struct loops *loops) |
| { |
| if (loops->larray) |
| { |
| unsigned i; |
| loop_p loop; |
| |
| /* Free the loop descriptors. */ |
| FOR_EACH_VEC_SAFE_ELT (loops->larray, i, loop) |
| { |
| if (!loop) |
| continue; |
| |
| flow_loop_free (loop); |
| } |
| |
| vec_free (loops->larray); |
| } |
| } |
| |
| /* Find the nodes contained within the LOOP with header HEADER. |
| Return the number of nodes within the loop. */ |
| |
| int |
| flow_loop_nodes_find (basic_block header, struct loop *loop) |
| { |
| vec<basic_block> stack = vNULL; |
| int num_nodes = 1; |
| edge latch; |
| edge_iterator latch_ei; |
| |
| header->loop_father = loop; |
| |
| FOR_EACH_EDGE (latch, latch_ei, loop->header->preds) |
| { |
| if (latch->src->loop_father == loop |
| || !dominated_by_p (CDI_DOMINATORS, latch->src, loop->header)) |
| continue; |
| |
| num_nodes++; |
| stack.safe_push (latch->src); |
| latch->src->loop_father = loop; |
| |
| while (!stack.is_empty ()) |
| { |
| basic_block node; |
| edge e; |
| edge_iterator ei; |
| |
| node = stack.pop (); |
| |
| FOR_EACH_EDGE (e, ei, node->preds) |
| { |
| basic_block ancestor = e->src; |
| |
| if (ancestor->loop_father != loop) |
| { |
| ancestor->loop_father = loop; |
| num_nodes++; |
| stack.safe_push (ancestor); |
| } |
| } |
| } |
| } |
| stack.release (); |
| |
| return num_nodes; |
| } |
| |
| /* Records the vector of superloops of the loop LOOP, whose immediate |
| superloop is FATHER. */ |
| |
| static void |
| establish_preds (struct loop *loop, struct loop *father) |
| { |
| loop_p ploop; |
| unsigned depth = loop_depth (father) + 1; |
| unsigned i; |
| |
| loop->superloops = 0; |
| vec_alloc (loop->superloops, depth); |
| FOR_EACH_VEC_SAFE_ELT (father->superloops, i, ploop) |
| loop->superloops->quick_push (ploop); |
| loop->superloops->quick_push (father); |
| |
| for (ploop = loop->inner; ploop; ploop = ploop->next) |
| establish_preds (ploop, loop); |
| } |
| |
| /* Add LOOP to the loop hierarchy tree where FATHER is father of the |
| added loop. If LOOP has some children, take care of that their |
| pred field will be initialized correctly. */ |
| |
| void |
| flow_loop_tree_node_add (struct loop *father, struct loop *loop) |
| { |
| loop->next = father->inner; |
| father->inner = loop; |
| |
| establish_preds (loop, father); |
| } |
| |
| /* Remove LOOP from the loop hierarchy tree. */ |
| |
| void |
| flow_loop_tree_node_remove (struct loop *loop) |
| { |
| struct loop *prev, *father; |
| |
| father = loop_outer (loop); |
| |
| /* Remove loop from the list of sons. */ |
| if (father->inner == loop) |
| father->inner = loop->next; |
| else |
| { |
| for (prev = father->inner; prev->next != loop; prev = prev->next) |
| continue; |
| prev->next = loop->next; |
| } |
| |
| loop->superloops = NULL; |
| } |
| |
| /* Allocates and returns new loop structure. */ |
| |
| struct loop * |
| alloc_loop (void) |
| { |
| struct loop *loop = ggc_cleared_alloc<struct loop> (); |
| |
| loop->exits = ggc_cleared_alloc<loop_exit> (); |
| loop->exits->next = loop->exits->prev = loop->exits; |
| loop->can_be_parallel = false; |
| loop->constraints = 0; |
| loop->nb_iterations_upper_bound = 0; |
| loop->nb_iterations_likely_upper_bound = 0; |
| loop->nb_iterations_estimate = 0; |
| return loop; |
| } |
| |
| /* Initializes loops structure LOOPS, reserving place for NUM_LOOPS loops |
| (including the root of the loop tree). */ |
| |
| void |
| init_loops_structure (struct function *fn, |
| struct loops *loops, unsigned num_loops) |
| { |
| struct loop *root; |
| |
| memset (loops, 0, sizeof *loops); |
| vec_alloc (loops->larray, num_loops); |
| |
| /* Dummy loop containing whole function. */ |
| root = alloc_loop (); |
| root->num_nodes = n_basic_blocks_for_fn (fn); |
| root->latch = EXIT_BLOCK_PTR_FOR_FN (fn); |
| root->header = ENTRY_BLOCK_PTR_FOR_FN (fn); |
| ENTRY_BLOCK_PTR_FOR_FN (fn)->loop_father = root; |
| EXIT_BLOCK_PTR_FOR_FN (fn)->loop_father = root; |
| |
| loops->larray->quick_push (root); |
| loops->tree_root = root; |
| } |
| |
| /* Returns whether HEADER is a loop header. */ |
| |
| bool |
| bb_loop_header_p (basic_block header) |
| { |
| edge_iterator ei; |
| edge e; |
| |
| /* If we have an abnormal predecessor, do not consider the |
| loop (not worth the problems). */ |
| if (bb_has_abnormal_pred (header)) |
| return false; |
| |
| /* Look for back edges where a predecessor is dominated |
| by this block. A natural loop has a single entry |
| node (header) that dominates all the nodes in the |
| loop. It also has single back edge to the header |
| from a latch node. */ |
| FOR_EACH_EDGE (e, ei, header->preds) |
| { |
| basic_block latch = e->src; |
| if (latch != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
| && dominated_by_p (CDI_DOMINATORS, latch, header)) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Find all the natural loops in the function and save in LOOPS structure and |
| recalculate loop_father information in basic block structures. |
| If LOOPS is non-NULL then the loop structures for already recorded loops |
| will be re-used and their number will not change. We assume that no |
| stale loops exist in LOOPS. |
| When LOOPS is NULL it is allocated and re-built from scratch. |
| Return the built LOOPS structure. */ |
| |
| struct loops * |
| flow_loops_find (struct loops *loops) |
| { |
| bool from_scratch = (loops == NULL); |
| int *rc_order; |
| int b; |
| unsigned i; |
| |
| /* Ensure that the dominators are computed. */ |
| calculate_dominance_info (CDI_DOMINATORS); |
| |
| if (!loops) |
| { |
| loops = ggc_cleared_alloc<struct loops> (); |
| init_loops_structure (cfun, loops, 1); |
| } |
| |
| /* Ensure that loop exits were released. */ |
| gcc_assert (loops->exits == NULL); |
| |
| /* Taking care of this degenerate case makes the rest of |
| this code simpler. */ |
| if (n_basic_blocks_for_fn (cfun) == NUM_FIXED_BLOCKS) |
| return loops; |
| |
| /* The root loop node contains all basic-blocks. */ |
| loops->tree_root->num_nodes = n_basic_blocks_for_fn (cfun); |
| |
| /* Compute depth first search order of the CFG so that outer |
| natural loops will be found before inner natural loops. */ |
| rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); |
| pre_and_rev_post_order_compute (NULL, rc_order, false); |
| |
| /* Gather all loop headers in reverse completion order and allocate |
| loop structures for loops that are not already present. */ |
| auto_vec<loop_p> larray (loops->larray->length ()); |
| for (b = 0; b < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; b++) |
| { |
| basic_block header = BASIC_BLOCK_FOR_FN (cfun, rc_order[b]); |
| if (bb_loop_header_p (header)) |
| { |
| struct loop *loop; |
| |
| /* The current active loop tree has valid loop-fathers for |
| header blocks. */ |
| if (!from_scratch |
| && header->loop_father->header == header) |
| { |
| loop = header->loop_father; |
| /* If we found an existing loop remove it from the |
| loop tree. It is going to be inserted again |
| below. */ |
| flow_loop_tree_node_remove (loop); |
| } |
| else |
| { |
| /* Otherwise allocate a new loop structure for the loop. */ |
| loop = alloc_loop (); |
| /* ??? We could re-use unused loop slots here. */ |
| loop->num = loops->larray->length (); |
| vec_safe_push (loops->larray, loop); |
| loop->header = header; |
| |
| if (!from_scratch |
| && dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "flow_loops_find: discovered new " |
| "loop %d with header %d\n", |
| loop->num, header->index); |
| } |
| /* Reset latch, we recompute it below. */ |
| loop->latch = NULL; |
| larray.safe_push (loop); |
| } |
| |
| /* Make blocks part of the loop root node at start. */ |
| header->loop_father = loops->tree_root; |
| } |
| |
| free (rc_order); |
| |
| /* Now iterate over the loops found, insert them into the loop tree |
| and assign basic-block ownership. */ |
| for (i = 0; i < larray.length (); ++i) |
| { |
| struct loop *loop = larray[i]; |
| basic_block header = loop->header; |
| edge_iterator ei; |
| edge e; |
| |
| flow_loop_tree_node_add (header->loop_father, loop); |
| loop->num_nodes = flow_loop_nodes_find (loop->header, loop); |
| |
| /* Look for the latch for this header block, if it has just a |
| single one. */ |
| FOR_EACH_EDGE (e, ei, header->preds) |
| { |
| basic_block latch = e->src; |
| |
| if (flow_bb_inside_loop_p (loop, latch)) |
| { |
| if (loop->latch != NULL) |
| { |
| /* More than one latch edge. */ |
| loop->latch = NULL; |
| break; |
| } |
| loop->latch = latch; |
| } |
| } |
| } |
| |
| return loops; |
| } |
| |
| /* Ratio of frequencies of edges so that one of more latch edges is |
| considered to belong to inner loop with same header. */ |
| #define HEAVY_EDGE_RATIO 8 |
| |
| /* Minimum number of samples for that we apply |
| find_subloop_latch_edge_by_profile heuristics. */ |
| #define HEAVY_EDGE_MIN_SAMPLES 10 |
| |
| /* If the profile info is available, finds an edge in LATCHES that much more |
| frequent than the remaining edges. Returns such an edge, or NULL if we do |
| not find one. |
| |
| We do not use guessed profile here, only the measured one. The guessed |
| profile is usually too flat and unreliable for this (and it is mostly based |
| on the loop structure of the program, so it does not make much sense to |
| derive the loop structure from it). */ |
| |
| static edge |
| find_subloop_latch_edge_by_profile (vec<edge> latches) |
| { |
| unsigned i; |
| edge e, me = NULL; |
| gcov_type mcount = 0, tcount = 0; |
| |
| FOR_EACH_VEC_ELT (latches, i, e) |
| { |
| if (e->count > mcount) |
| { |
| me = e; |
| mcount = e->count; |
| } |
| tcount += e->count; |
| } |
| |
| if (tcount < HEAVY_EDGE_MIN_SAMPLES |
| || (tcount - mcount) * HEAVY_EDGE_RATIO > tcount) |
| return NULL; |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "Found latch edge %d -> %d using profile information.\n", |
| me->src->index, me->dest->index); |
| return me; |
| } |
| |
| /* Among LATCHES, guesses a latch edge of LOOP corresponding to subloop, based |
| on the structure of induction variables. Returns this edge, or NULL if we |
| do not find any. |
| |
| We are quite conservative, and look just for an obvious simple innermost |
| loop (which is the case where we would lose the most performance by not |
| disambiguating the loop). More precisely, we look for the following |
| situation: The source of the chosen latch edge dominates sources of all |
| the other latch edges. Additionally, the header does not contain a phi node |
| such that the argument from the chosen edge is equal to the argument from |
| another edge. */ |
| |
| static edge |
| find_subloop_latch_edge_by_ivs (struct loop *loop ATTRIBUTE_UNUSED, vec<edge> latches) |
| { |
| edge e, latch = latches[0]; |
| unsigned i; |
| gphi *phi; |
| gphi_iterator psi; |
| tree lop; |
| basic_block bb; |
| |
| /* Find the candidate for the latch edge. */ |
| for (i = 1; latches.iterate (i, &e); i++) |
| if (dominated_by_p (CDI_DOMINATORS, latch->src, e->src)) |
| latch = e; |
| |
| /* Verify that it dominates all the latch edges. */ |
| FOR_EACH_VEC_ELT (latches, i, e) |
| if (!dominated_by_p (CDI_DOMINATORS, e->src, latch->src)) |
| return NULL; |
| |
| /* Check for a phi node that would deny that this is a latch edge of |
| a subloop. */ |
| for (psi = gsi_start_phis (loop->header); !gsi_end_p (psi); gsi_next (&psi)) |
| { |
| phi = psi.phi (); |
| lop = PHI_ARG_DEF_FROM_EDGE (phi, latch); |
| |
| /* Ignore the values that are not changed inside the subloop. */ |
| if (TREE_CODE (lop) != SSA_NAME |
| || SSA_NAME_DEF_STMT (lop) == phi) |
| continue; |
| bb = gimple_bb (SSA_NAME_DEF_STMT (lop)); |
| if (!bb || !flow_bb_inside_loop_p (loop, bb)) |
| continue; |
| |
| FOR_EACH_VEC_ELT (latches, i, e) |
| if (e != latch |
| && PHI_ARG_DEF_FROM_EDGE (phi, e) == lop) |
| return NULL; |
| } |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "Found latch edge %d -> %d using iv structure.\n", |
| latch->src->index, latch->dest->index); |
| return latch; |
| } |
| |
| /* If we can determine that one of the several latch edges of LOOP behaves |
| as a latch edge of a separate subloop, returns this edge. Otherwise |
| returns NULL. */ |
| |
| static edge |
| find_subloop_latch_edge (struct loop *loop) |
| { |
| vec<edge> latches = get_loop_latch_edges (loop); |
| edge latch = NULL; |
| |
| if (latches.length () > 1) |
| { |
| latch = find_subloop_latch_edge_by_profile (latches); |
| |
| if (!latch |
| /* We consider ivs to guess the latch edge only in SSA. Perhaps we |
| should use cfghook for this, but it is hard to imagine it would |
| be useful elsewhere. */ |
| && current_ir_type () == IR_GIMPLE) |
| latch = find_subloop_latch_edge_by_ivs (loop, latches); |
| } |
| |
| latches.release (); |
| return latch; |
| } |
| |
| /* Callback for make_forwarder_block. Returns true if the edge E is marked |
| in the set MFB_REIS_SET. */ |
| |
| static hash_set<edge> *mfb_reis_set; |
| static bool |
| mfb_redirect_edges_in_set (edge e) |
| { |
| return mfb_reis_set->contains (e); |
| } |
| |
| /* Creates a subloop of LOOP with latch edge LATCH. */ |
| |
| static void |
| form_subloop (struct loop *loop, edge latch) |
| { |
| edge_iterator ei; |
| edge e, new_entry; |
| struct loop *new_loop; |
| |
| mfb_reis_set = new hash_set<edge>; |
| FOR_EACH_EDGE (e, ei, loop->header->preds) |
| { |
| if (e != latch) |
| mfb_reis_set->add (e); |
| } |
| new_entry = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
| NULL); |
| delete mfb_reis_set; |
| |
| loop->header = new_entry->src; |
| |
| /* Find the blocks and subloops that belong to the new loop, and add it to |
| the appropriate place in the loop tree. */ |
| new_loop = alloc_loop (); |
| new_loop->header = new_entry->dest; |
| new_loop->latch = latch->src; |
| add_loop (new_loop, loop); |
| } |
| |
| /* Make all the latch edges of LOOP to go to a single forwarder block -- |
| a new latch of LOOP. */ |
| |
| static void |
| merge_latch_edges (struct loop *loop) |
| { |
| vec<edge> latches = get_loop_latch_edges (loop); |
| edge latch, e; |
| unsigned i; |
| |
| gcc_assert (latches.length () > 0); |
| |
| if (latches.length () == 1) |
| loop->latch = latches[0]->src; |
| else |
| { |
| if (dump_file) |
| fprintf (dump_file, "Merged latch edges of loop %d\n", loop->num); |
| |
| mfb_reis_set = new hash_set<edge>; |
| FOR_EACH_VEC_ELT (latches, i, e) |
| mfb_reis_set->add (e); |
| latch = make_forwarder_block (loop->header, mfb_redirect_edges_in_set, |
| NULL); |
| delete mfb_reis_set; |
| |
| loop->header = latch->dest; |
| loop->latch = latch->src; |
| } |
| |
| latches.release (); |
| } |
| |
| /* LOOP may have several latch edges. Transform it into (possibly several) |
| loops with single latch edge. */ |
| |
| static void |
| disambiguate_multiple_latches (struct loop *loop) |
| { |
| edge e; |
| |
| /* We eliminate the multiple latches by splitting the header to the forwarder |
| block F and the rest R, and redirecting the edges. There are two cases: |
| |
| 1) If there is a latch edge E that corresponds to a subloop (we guess |
| that based on profile -- if it is taken much more often than the |
| remaining edges; and on trees, using the information about induction |
| variables of the loops), we redirect E to R, all the remaining edges to |
| F, then rescan the loops and try again for the outer loop. |
| 2) If there is no such edge, we redirect all latch edges to F, and the |
| entry edges to R, thus making F the single latch of the loop. */ |
| |
| if (dump_file) |
| fprintf (dump_file, "Disambiguating loop %d with multiple latches\n", |
| loop->num); |
| |
| /* During latch merging, we may need to redirect the entry edges to a new |
| block. This would cause problems if the entry edge was the one from the |
| entry block. To avoid having to handle this case specially, split |
| such entry edge. */ |
| e = find_edge (ENTRY_BLOCK_PTR_FOR_FN (cfun), loop->header); |
| if (e) |
| split_edge (e); |
| |
| while (1) |
| { |
| e = find_subloop_latch_edge (loop); |
| if (!e) |
| break; |
| |
| form_subloop (loop, e); |
| } |
| |
| merge_latch_edges (loop); |
| } |
| |
| /* Split loops with multiple latch edges. */ |
| |
| void |
| disambiguate_loops_with_multiple_latches (void) |
| { |
| struct loop *loop; |
| |
| FOR_EACH_LOOP (loop, 0) |
| { |
| if (!loop->latch) |
| disambiguate_multiple_latches (loop); |
| } |
| } |
| |
| /* Return nonzero if basic block BB belongs to LOOP. */ |
| bool |
| flow_bb_inside_loop_p (const struct loop *loop, const_basic_block bb) |
| { |
| struct loop *source_loop; |
| |
| if (bb == ENTRY_BLOCK_PTR_FOR_FN (cfun) |
| || bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| return 0; |
| |
| source_loop = bb->loop_father; |
| return loop == source_loop || flow_loop_nested_p (loop, source_loop); |
| } |
| |
| /* Enumeration predicate for get_loop_body_with_size. */ |
| static bool |
| glb_enum_p (const_basic_block bb, const void *glb_loop) |
| { |
| const struct loop *const loop = (const struct loop *) glb_loop; |
| return (bb != loop->header |
| && dominated_by_p (CDI_DOMINATORS, bb, loop->header)); |
| } |
| |
| /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
| order against direction of edges from latch. Specially, if |
| header != latch, latch is the 1-st block. LOOP cannot be the fake |
| loop tree root, and its size must be at most MAX_SIZE. The blocks |
| in the LOOP body are stored to BODY, and the size of the LOOP is |
| returned. */ |
| |
| unsigned |
| get_loop_body_with_size (const struct loop *loop, basic_block *body, |
| unsigned max_size) |
| { |
| return dfs_enumerate_from (loop->header, 1, glb_enum_p, |
| body, max_size, loop); |
| } |
| |
| /* Gets basic blocks of a LOOP. Header is the 0-th block, rest is in dfs |
| order against direction of edges from latch. Specially, if |
| header != latch, latch is the 1-st block. */ |
| |
| basic_block * |
| get_loop_body (const struct loop *loop) |
| { |
| basic_block *body, bb; |
| unsigned tv = 0; |
| |
| gcc_assert (loop->num_nodes); |
| |
| body = XNEWVEC (basic_block, loop->num_nodes); |
| |
| if (loop->latch == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| { |
| /* There may be blocks unreachable from EXIT_BLOCK, hence we need to |
| special-case the fake loop that contains the whole function. */ |
| gcc_assert (loop->num_nodes == (unsigned) n_basic_blocks_for_fn (cfun)); |
| body[tv++] = loop->header; |
| body[tv++] = EXIT_BLOCK_PTR_FOR_FN (cfun); |
| FOR_EACH_BB_FN (bb, cfun) |
| body[tv++] = bb; |
| } |
| else |
| tv = get_loop_body_with_size (loop, body, loop->num_nodes); |
| |
| gcc_assert (tv == loop->num_nodes); |
| return body; |
| } |
| |
| /* Fills dominance descendants inside LOOP of the basic block BB into |
| array TOVISIT from index *TV. */ |
| |
| static void |
| fill_sons_in_loop (const struct loop *loop, basic_block bb, |
| basic_block *tovisit, int *tv) |
| { |
| basic_block son, postpone = NULL; |
| |
| tovisit[(*tv)++] = bb; |
| for (son = first_dom_son (CDI_DOMINATORS, bb); |
| son; |
| son = next_dom_son (CDI_DOMINATORS, son)) |
| { |
| if (!flow_bb_inside_loop_p (loop, son)) |
| continue; |
| |
| if (dominated_by_p (CDI_DOMINATORS, loop->latch, son)) |
| { |
| postpone = son; |
| continue; |
| } |
| fill_sons_in_loop (loop, son, tovisit, tv); |
| } |
| |
| if (postpone) |
| fill_sons_in_loop (loop, postpone, tovisit, tv); |
| } |
| |
| /* Gets body of a LOOP (that must be different from the outermost loop) |
| sorted by dominance relation. Additionally, if a basic block s dominates |
| the latch, then only blocks dominated by s are be after it. */ |
| |
| basic_block * |
| get_loop_body_in_dom_order (const struct loop *loop) |
| { |
| basic_block *tovisit; |
| int tv; |
| |
| gcc_assert (loop->num_nodes); |
| |
| tovisit = XNEWVEC (basic_block, loop->num_nodes); |
| |
| gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
| |
| tv = 0; |
| fill_sons_in_loop (loop, loop->header, tovisit, &tv); |
| |
| gcc_assert (tv == (int) loop->num_nodes); |
| |
| return tovisit; |
| } |
| |
| /* Gets body of a LOOP sorted via provided BB_COMPARATOR. */ |
| |
| basic_block * |
| get_loop_body_in_custom_order (const struct loop *loop, |
| int (*bb_comparator) (const void *, const void *)) |
| { |
| basic_block *bbs = get_loop_body (loop); |
| |
| qsort (bbs, loop->num_nodes, sizeof (basic_block), bb_comparator); |
| |
| return bbs; |
| } |
| |
| /* Get body of a LOOP in breadth first sort order. */ |
| |
| basic_block * |
| get_loop_body_in_bfs_order (const struct loop *loop) |
| { |
| basic_block *blocks; |
| basic_block bb; |
| bitmap visited; |
| unsigned int i = 1; |
| unsigned int vc = 0; |
| |
| gcc_assert (loop->num_nodes); |
| gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
| |
| blocks = XNEWVEC (basic_block, loop->num_nodes); |
| visited = BITMAP_ALLOC (NULL); |
| blocks[0] = loop->header; |
| bitmap_set_bit (visited, loop->header->index); |
| while (i < loop->num_nodes) |
| { |
| edge e; |
| edge_iterator ei; |
| gcc_assert (i > vc); |
| bb = blocks[vc++]; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| if (flow_bb_inside_loop_p (loop, e->dest)) |
| { |
| /* This bb is now visited. */ |
| if (bitmap_set_bit (visited, e->dest->index)) |
| blocks[i++] = e->dest; |
| } |
| } |
| } |
| |
| BITMAP_FREE (visited); |
| return blocks; |
| } |
| |
| /* Hash function for struct loop_exit. */ |
| |
| hashval_t |
| loop_exit_hasher::hash (loop_exit *exit) |
| { |
| return htab_hash_pointer (exit->e); |
| } |
| |
| /* Equality function for struct loop_exit. Compares with edge. */ |
| |
| bool |
| loop_exit_hasher::equal (loop_exit *exit, edge e) |
| { |
| return exit->e == e; |
| } |
| |
| /* Frees the list of loop exit descriptions EX. */ |
| |
| void |
| loop_exit_hasher::remove (loop_exit *exit) |
| { |
| loop_exit *next; |
| for (; exit; exit = next) |
| { |
| next = exit->next_e; |
| |
| exit->next->prev = exit->prev; |
| exit->prev->next = exit->next; |
| |
| ggc_free (exit); |
| } |
| } |
| |
| /* Returns the list of records for E as an exit of a loop. */ |
| |
| static struct loop_exit * |
| get_exit_descriptions (edge e) |
| { |
| return current_loops->exits->find_with_hash (e, htab_hash_pointer (e)); |
| } |
| |
| /* Updates the lists of loop exits in that E appears. |
| If REMOVED is true, E is being removed, and we |
| just remove it from the lists of exits. |
| If NEW_EDGE is true and E is not a loop exit, we |
| do not try to remove it from loop exit lists. */ |
| |
| void |
| rescan_loop_exit (edge e, bool new_edge, bool removed) |
| { |
| struct loop_exit *exits = NULL, *exit; |
| struct loop *aloop, *cloop; |
| |
| if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| return; |
| |
| if (!removed |
| && e->src->loop_father != NULL |
| && e->dest->loop_father != NULL |
| && !flow_bb_inside_loop_p (e->src->loop_father, e->dest)) |
| { |
| cloop = find_common_loop (e->src->loop_father, e->dest->loop_father); |
| for (aloop = e->src->loop_father; |
| aloop != cloop; |
| aloop = loop_outer (aloop)) |
| { |
| exit = ggc_alloc<loop_exit> (); |
| exit->e = e; |
| |
| exit->next = aloop->exits->next; |
| exit->prev = aloop->exits; |
| exit->next->prev = exit; |
| exit->prev->next = exit; |
| |
| exit->next_e = exits; |
| exits = exit; |
| } |
| } |
| |
| if (!exits && new_edge) |
| return; |
| |
| loop_exit **slot |
| = current_loops->exits->find_slot_with_hash (e, htab_hash_pointer (e), |
| exits ? INSERT : NO_INSERT); |
| if (!slot) |
| return; |
| |
| if (exits) |
| { |
| if (*slot) |
| loop_exit_hasher::remove (*slot); |
| *slot = exits; |
| } |
| else |
| current_loops->exits->clear_slot (slot); |
| } |
| |
| /* For each loop, record list of exit edges, and start maintaining these |
| lists. */ |
| |
| void |
| record_loop_exits (void) |
| { |
| basic_block bb; |
| edge_iterator ei; |
| edge e; |
| |
| if (!current_loops) |
| return; |
| |
| if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| return; |
| loops_state_set (LOOPS_HAVE_RECORDED_EXITS); |
| |
| gcc_assert (current_loops->exits == NULL); |
| current_loops->exits |
| = hash_table<loop_exit_hasher>::create_ggc (2 * number_of_loops (cfun)); |
| |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| rescan_loop_exit (e, true, false); |
| } |
| } |
| } |
| |
| /* Dumps information about the exit in *SLOT to FILE. |
| Callback for htab_traverse. */ |
| |
| int |
| dump_recorded_exit (loop_exit **slot, FILE *file) |
| { |
| struct loop_exit *exit = *slot; |
| unsigned n = 0; |
| edge e = exit->e; |
| |
| for (; exit != NULL; exit = exit->next_e) |
| n++; |
| |
| fprintf (file, "Edge %d->%d exits %u loops\n", |
| e->src->index, e->dest->index, n); |
| |
| return 1; |
| } |
| |
| /* Dumps the recorded exits of loops to FILE. */ |
| |
| extern void dump_recorded_exits (FILE *); |
| void |
| dump_recorded_exits (FILE *file) |
| { |
| if (!current_loops->exits) |
| return; |
| current_loops->exits->traverse<FILE *, dump_recorded_exit> (file); |
| } |
| |
| /* Releases lists of loop exits. */ |
| |
| void |
| release_recorded_exits (function *fn) |
| { |
| gcc_assert (loops_state_satisfies_p (fn, LOOPS_HAVE_RECORDED_EXITS)); |
| loops_for_fn (fn)->exits->empty (); |
| loops_for_fn (fn)->exits = NULL; |
| loops_state_clear (fn, LOOPS_HAVE_RECORDED_EXITS); |
| } |
| |
| /* Returns the list of the exit edges of a LOOP. */ |
| |
| vec<edge> |
| get_loop_exit_edges (const struct loop *loop) |
| { |
| vec<edge> edges = vNULL; |
| edge e; |
| unsigned i; |
| basic_block *body; |
| edge_iterator ei; |
| struct loop_exit *exit; |
| |
| gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
| |
| /* If we maintain the lists of exits, use them. Otherwise we must |
| scan the body of the loop. */ |
| if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| { |
| for (exit = loop->exits->next; exit->e; exit = exit->next) |
| edges.safe_push (exit->e); |
| } |
| else |
| { |
| body = get_loop_body (loop); |
| for (i = 0; i < loop->num_nodes; i++) |
| FOR_EACH_EDGE (e, ei, body[i]->succs) |
| { |
| if (!flow_bb_inside_loop_p (loop, e->dest)) |
| edges.safe_push (e); |
| } |
| free (body); |
| } |
| |
| return edges; |
| } |
| |
| /* Counts the number of conditional branches inside LOOP. */ |
| |
| unsigned |
| num_loop_branches (const struct loop *loop) |
| { |
| unsigned i, n; |
| basic_block * body; |
| |
| gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun)); |
| |
| body = get_loop_body (loop); |
| n = 0; |
| for (i = 0; i < loop->num_nodes; i++) |
| if (EDGE_COUNT (body[i]->succs) >= 2) |
| n++; |
| free (body); |
| |
| return n; |
| } |
| |
| /* Adds basic block BB to LOOP. */ |
| void |
| add_bb_to_loop (basic_block bb, struct loop *loop) |
| { |
| unsigned i; |
| loop_p ploop; |
| edge_iterator ei; |
| edge e; |
| |
| gcc_assert (bb->loop_father == NULL); |
| bb->loop_father = loop; |
| loop->num_nodes++; |
| FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
| ploop->num_nodes++; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| rescan_loop_exit (e, true, false); |
| } |
| FOR_EACH_EDGE (e, ei, bb->preds) |
| { |
| rescan_loop_exit (e, true, false); |
| } |
| } |
| |
| /* Remove basic block BB from loops. */ |
| void |
| remove_bb_from_loops (basic_block bb) |
| { |
| unsigned i; |
| struct loop *loop = bb->loop_father; |
| loop_p ploop; |
| edge_iterator ei; |
| edge e; |
| |
| gcc_assert (loop != NULL); |
| loop->num_nodes--; |
| FOR_EACH_VEC_SAFE_ELT (loop->superloops, i, ploop) |
| ploop->num_nodes--; |
| bb->loop_father = NULL; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| rescan_loop_exit (e, false, true); |
| } |
| FOR_EACH_EDGE (e, ei, bb->preds) |
| { |
| rescan_loop_exit (e, false, true); |
| } |
| } |
| |
| /* Finds nearest common ancestor in loop tree for given loops. */ |
| struct loop * |
| find_common_loop (struct loop *loop_s, struct loop *loop_d) |
| { |
| unsigned sdepth, ddepth; |
| |
| if (!loop_s) return loop_d; |
| if (!loop_d) return loop_s; |
| |
| sdepth = loop_depth (loop_s); |
| ddepth = loop_depth (loop_d); |
| |
| if (sdepth < ddepth) |
| loop_d = (*loop_d->superloops)[sdepth]; |
| else if (sdepth > ddepth) |
| loop_s = (*loop_s->superloops)[ddepth]; |
| |
| while (loop_s != loop_d) |
| { |
| loop_s = loop_outer (loop_s); |
| loop_d = loop_outer (loop_d); |
| } |
| return loop_s; |
| } |
| |
| /* Removes LOOP from structures and frees its data. */ |
| |
| void |
| delete_loop (struct loop *loop) |
| { |
| /* Remove the loop from structure. */ |
| flow_loop_tree_node_remove (loop); |
| |
| /* Remove loop from loops array. */ |
| (*current_loops->larray)[loop->num] = NULL; |
| |
| /* Free loop data. */ |
| flow_loop_free (loop); |
| } |
| |
| /* Cancels the LOOP; it must be innermost one. */ |
| |
| static void |
| cancel_loop (struct loop *loop) |
| { |
| basic_block *bbs; |
| unsigned i; |
| struct loop *outer = loop_outer (loop); |
| |
| gcc_assert (!loop->inner); |
| |
| /* Move blocks up one level (they should be removed as soon as possible). */ |
| bbs = get_loop_body (loop); |
| for (i = 0; i < loop->num_nodes; i++) |
| bbs[i]->loop_father = outer; |
| |
| free (bbs); |
| delete_loop (loop); |
| } |
| |
| /* Cancels LOOP and all its subloops. */ |
| void |
| cancel_loop_tree (struct loop *loop) |
| { |
| while (loop->inner) |
| cancel_loop_tree (loop->inner); |
| cancel_loop (loop); |
| } |
| |
| /* Checks that information about loops is correct |
| -- sizes of loops are all right |
| -- results of get_loop_body really belong to the loop |
| -- loop header have just single entry edge and single latch edge |
| -- loop latches have only single successor that is header of their loop |
| -- irreducible loops are correctly marked |
| -- the cached loop depth and loop father of each bb is correct |
| */ |
| DEBUG_FUNCTION void |
| verify_loop_structure (void) |
| { |
| unsigned *sizes, i, j; |
| basic_block bb, *bbs; |
| struct loop *loop; |
| int err = 0; |
| edge e; |
| unsigned num = number_of_loops (cfun); |
| struct loop_exit *exit, *mexit; |
| bool dom_available = dom_info_available_p (CDI_DOMINATORS); |
| |
| if (loops_state_satisfies_p (LOOPS_NEED_FIXUP)) |
| { |
| error ("loop verification on loop tree that needs fixup"); |
| err = 1; |
| } |
| |
| /* We need up-to-date dominators, compute or verify them. */ |
| if (!dom_available) |
| calculate_dominance_info (CDI_DOMINATORS); |
| else |
| verify_dominators (CDI_DOMINATORS); |
| |
| /* Check the loop tree root. */ |
| if (current_loops->tree_root->header != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
| || current_loops->tree_root->latch != EXIT_BLOCK_PTR_FOR_FN (cfun) |
| || (current_loops->tree_root->num_nodes |
| != (unsigned) n_basic_blocks_for_fn (cfun))) |
| { |
| error ("corrupt loop tree root"); |
| err = 1; |
| } |
| |
| /* Check the headers. */ |
| FOR_EACH_BB_FN (bb, cfun) |
| if (bb_loop_header_p (bb)) |
| { |
| if (bb->loop_father->header == NULL) |
| { |
| error ("loop with header %d marked for removal", bb->index); |
| err = 1; |
| } |
| else if (bb->loop_father->header != bb) |
| { |
| error ("loop with header %d not in loop tree", bb->index); |
| err = 1; |
| } |
| } |
| else if (bb->loop_father->header == bb) |
| { |
| error ("non-loop with header %d not marked for removal", bb->index); |
| err = 1; |
| } |
| |
| /* Check the recorded loop father and sizes of loops. */ |
| auto_sbitmap visited (last_basic_block_for_fn (cfun)); |
| bitmap_clear (visited); |
| bbs = XNEWVEC (basic_block, n_basic_blocks_for_fn (cfun)); |
| FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| { |
| unsigned n; |
| |
| if (loop->header == NULL) |
| { |
| error ("removed loop %d in loop tree", loop->num); |
| err = 1; |
| continue; |
| } |
| |
| n = get_loop_body_with_size (loop, bbs, n_basic_blocks_for_fn (cfun)); |
| if (loop->num_nodes != n) |
| { |
| error ("size of loop %d should be %d, not %d", |
| loop->num, n, loop->num_nodes); |
| err = 1; |
| } |
| |
| for (j = 0; j < n; j++) |
| { |
| bb = bbs[j]; |
| |
| if (!flow_bb_inside_loop_p (loop, bb)) |
| { |
| error ("bb %d does not belong to loop %d", |
| bb->index, loop->num); |
| err = 1; |
| } |
| |
| /* Ignore this block if it is in an inner loop. */ |
| if (bitmap_bit_p (visited, bb->index)) |
| continue; |
| bitmap_set_bit (visited, bb->index); |
| |
| if (bb->loop_father != loop) |
| { |
| error ("bb %d has father loop %d, should be loop %d", |
| bb->index, bb->loop_father->num, loop->num); |
| err = 1; |
| } |
| } |
| } |
| free (bbs); |
| |
| /* Check headers and latches. */ |
| FOR_EACH_LOOP (loop, 0) |
| { |
| i = loop->num; |
| if (loop->header == NULL) |
| continue; |
| if (!bb_loop_header_p (loop->header)) |
| { |
| error ("loop %d%'s header is not a loop header", i); |
| err = 1; |
| } |
| if (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS) |
| && EDGE_COUNT (loop->header->preds) != 2) |
| { |
| error ("loop %d%'s header does not have exactly 2 entries", i); |
| err = 1; |
| } |
| if (loop->latch) |
| { |
| if (!find_edge (loop->latch, loop->header)) |
| { |
| error ("loop %d%'s latch does not have an edge to its header", i); |
| err = 1; |
| } |
| if (!dominated_by_p (CDI_DOMINATORS, loop->latch, loop->header)) |
| { |
| error ("loop %d%'s latch is not dominated by its header", i); |
| err = 1; |
| } |
| } |
| if (loops_state_satisfies_p (LOOPS_HAVE_SIMPLE_LATCHES)) |
| { |
| if (!single_succ_p (loop->latch)) |
| { |
| error ("loop %d%'s latch does not have exactly 1 successor", i); |
| err = 1; |
| } |
| if (single_succ (loop->latch) != loop->header) |
| { |
| error ("loop %d%'s latch does not have header as successor", i); |
| err = 1; |
| } |
| if (loop->latch->loop_father != loop) |
| { |
| error ("loop %d%'s latch does not belong directly to it", i); |
| err = 1; |
| } |
| } |
| if (loop->header->loop_father != loop) |
| { |
| error ("loop %d%'s header does not belong directly to it", i); |
| err = 1; |
| } |
| if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS) |
| && (loop_latch_edge (loop)->flags & EDGE_IRREDUCIBLE_LOOP)) |
| { |
| error ("loop %d%'s latch is marked as part of irreducible region", i); |
| err = 1; |
| } |
| } |
| |
| /* Check irreducible loops. */ |
| if (loops_state_satisfies_p (LOOPS_HAVE_MARKED_IRREDUCIBLE_REGIONS)) |
| { |
| /* Record old info. */ |
| auto_sbitmap irreds (last_basic_block_for_fn (cfun)); |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| edge_iterator ei; |
| if (bb->flags & BB_IRREDUCIBLE_LOOP) |
| bitmap_set_bit (irreds, bb->index); |
| else |
| bitmap_clear_bit (irreds, bb->index); |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| if (e->flags & EDGE_IRREDUCIBLE_LOOP) |
| e->flags |= EDGE_ALL_FLAGS + 1; |
| } |
| |
| /* Recount it. */ |
| mark_irreducible_loops (); |
| |
| /* Compare. */ |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| edge_iterator ei; |
| |
| if ((bb->flags & BB_IRREDUCIBLE_LOOP) |
| && !bitmap_bit_p (irreds, bb->index)) |
| { |
| error ("basic block %d should be marked irreducible", bb->index); |
| err = 1; |
| } |
| else if (!(bb->flags & BB_IRREDUCIBLE_LOOP) |
| && bitmap_bit_p (irreds, bb->index)) |
| { |
| error ("basic block %d should not be marked irreducible", bb->index); |
| err = 1; |
| } |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| if ((e->flags & EDGE_IRREDUCIBLE_LOOP) |
| && !(e->flags & (EDGE_ALL_FLAGS + 1))) |
| { |
| error ("edge from %d to %d should be marked irreducible", |
| e->src->index, e->dest->index); |
| err = 1; |
| } |
| else if (!(e->flags & EDGE_IRREDUCIBLE_LOOP) |
| && (e->flags & (EDGE_ALL_FLAGS + 1))) |
| { |
| error ("edge from %d to %d should not be marked irreducible", |
| e->src->index, e->dest->index); |
| err = 1; |
| } |
| e->flags &= ~(EDGE_ALL_FLAGS + 1); |
| } |
| } |
| } |
| |
| /* Check the recorded loop exits. */ |
| FOR_EACH_LOOP (loop, 0) |
| { |
| if (!loop->exits || loop->exits->e != NULL) |
| { |
| error ("corrupted head of the exits list of loop %d", |
| loop->num); |
| err = 1; |
| } |
| else |
| { |
| /* Check that the list forms a cycle, and all elements except |
| for the head are nonnull. */ |
| for (mexit = loop->exits, exit = mexit->next, i = 0; |
| exit->e && exit != mexit; |
| exit = exit->next) |
| { |
| if (i++ & 1) |
| mexit = mexit->next; |
| } |
| |
| if (exit != loop->exits) |
| { |
| error ("corrupted exits list of loop %d", loop->num); |
| err = 1; |
| } |
| } |
| |
| if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| { |
| if (loop->exits->next != loop->exits) |
| { |
| error ("nonempty exits list of loop %d, but exits are not recorded", |
| loop->num); |
| err = 1; |
| } |
| } |
| } |
| |
| if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| { |
| unsigned n_exits = 0, eloops; |
| |
| sizes = XCNEWVEC (unsigned, num); |
| memset (sizes, 0, sizeof (unsigned) * num); |
| FOR_EACH_BB_FN (bb, cfun) |
| { |
| edge_iterator ei; |
| if (bb->loop_father == current_loops->tree_root) |
| continue; |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| { |
| if (flow_bb_inside_loop_p (bb->loop_father, e->dest)) |
| continue; |
| |
| n_exits++; |
| exit = get_exit_descriptions (e); |
| if (!exit) |
| { |
| error ("exit %d->%d not recorded", |
| e->src->index, e->dest->index); |
| err = 1; |
| } |
| eloops = 0; |
| for (; exit; exit = exit->next_e) |
| eloops++; |
| |
| for (loop = bb->loop_father; |
| loop != e->dest->loop_father |
| /* When a loop exit is also an entry edge which |
| can happen when avoiding CFG manipulations |
| then the last loop exited is the outer loop |
| of the loop entered. */ |
| && loop != loop_outer (e->dest->loop_father); |
| loop = loop_outer (loop)) |
| { |
| eloops--; |
| sizes[loop->num]++; |
| } |
| |
| if (eloops != 0) |
| { |
| error ("wrong list of exited loops for edge %d->%d", |
| e->src->index, e->dest->index); |
| err = 1; |
| } |
| } |
| } |
| |
| if (n_exits != current_loops->exits->elements ()) |
| { |
| error ("too many loop exits recorded"); |
| err = 1; |
| } |
| |
| FOR_EACH_LOOP (loop, 0) |
| { |
| eloops = 0; |
| for (exit = loop->exits->next; exit->e; exit = exit->next) |
| eloops++; |
| if (eloops != sizes[loop->num]) |
| { |
| error ("%d exits recorded for loop %d (having %d exits)", |
| eloops, loop->num, sizes[loop->num]); |
| err = 1; |
| } |
| } |
| |
| free (sizes); |
| } |
| |
| gcc_assert (!err); |
| |
| if (!dom_available) |
| free_dominance_info (CDI_DOMINATORS); |
| } |
| |
| /* Returns latch edge of LOOP. */ |
| edge |
| loop_latch_edge (const struct loop *loop) |
| { |
| return find_edge (loop->latch, loop->header); |
| } |
| |
| /* Returns preheader edge of LOOP. */ |
| edge |
| loop_preheader_edge (const struct loop *loop) |
| { |
| edge e; |
| edge_iterator ei; |
| |
| gcc_assert (loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS)); |
| |
| FOR_EACH_EDGE (e, ei, loop->header->preds) |
| if (e->src != loop->latch) |
| break; |
| |
| return e; |
| } |
| |
| /* Returns true if E is an exit of LOOP. */ |
| |
| bool |
| loop_exit_edge_p (const struct loop *loop, const_edge e) |
| { |
| return (flow_bb_inside_loop_p (loop, e->src) |
| && !flow_bb_inside_loop_p (loop, e->dest)); |
| } |
| |
| /* Returns the single exit edge of LOOP, or NULL if LOOP has either no exit |
| or more than one exit. If loops do not have the exits recorded, NULL |
| is returned always. */ |
| |
| edge |
| single_exit (const struct loop *loop) |
| { |
| struct loop_exit *exit = loop->exits->next; |
| |
| if (!loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)) |
| return NULL; |
| |
| if (exit->e && exit->next == loop->exits) |
| return exit->e; |
| else |
| return NULL; |
| } |
| |
| /* Returns true when BB has an incoming edge exiting LOOP. */ |
| |
| bool |
| loop_exits_to_bb_p (struct loop *loop, basic_block bb) |
| { |
| edge e; |
| edge_iterator ei; |
| |
| FOR_EACH_EDGE (e, ei, bb->preds) |
| if (loop_exit_edge_p (loop, e)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Returns true when BB has an outgoing edge exiting LOOP. */ |
| |
| bool |
| loop_exits_from_bb_p (struct loop *loop, basic_block bb) |
| { |
| edge e; |
| edge_iterator ei; |
| |
| FOR_EACH_EDGE (e, ei, bb->succs) |
| if (loop_exit_edge_p (loop, e)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Return location corresponding to the loop control condition if possible. */ |
| |
| location_t |
| get_loop_location (struct loop *loop) |
| { |
| rtx_insn *insn = NULL; |
| struct niter_desc *desc = NULL; |
| edge exit; |
| |
| /* For a for or while loop, we would like to return the location |
| of the for or while statement, if possible. To do this, look |
| for the branch guarding the loop back-edge. */ |
| |
| /* If this is a simple loop with an in_edge, then the loop control |
| branch is typically at the end of its source. */ |
| desc = get_simple_loop_desc (loop); |
| if (desc->in_edge) |
| { |
| FOR_BB_INSNS_REVERSE (desc->in_edge->src, insn) |
| { |
| if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
| return INSN_LOCATION (insn); |
| } |
| } |
| /* If loop has a single exit, then the loop control branch |
| must be at the end of its source. */ |
| if ((exit = single_exit (loop))) |
| { |
| FOR_BB_INSNS_REVERSE (exit->src, insn) |
| { |
| if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
| return INSN_LOCATION (insn); |
| } |
| } |
| /* Next check the latch, to see if it is non-empty. */ |
| FOR_BB_INSNS_REVERSE (loop->latch, insn) |
| { |
| if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
| return INSN_LOCATION (insn); |
| } |
| /* Finally, if none of the above identifies the loop control branch, |
| return the first location in the loop header. */ |
| FOR_BB_INSNS (loop->header, insn) |
| { |
| if (INSN_P (insn) && INSN_HAS_LOCATION (insn)) |
| return INSN_LOCATION (insn); |
| } |
| /* If all else fails, simply return the current function location. */ |
| return DECL_SOURCE_LOCATION (current_function_decl); |
| } |
| |
| /* Records that every statement in LOOP is executed I_BOUND times. |
| REALISTIC is true if I_BOUND is expected to be close to the real number |
| of iterations. UPPER is true if we are sure the loop iterates at most |
| I_BOUND times. */ |
| |
| void |
| record_niter_bound (struct loop *loop, const widest_int &i_bound, |
| bool realistic, bool upper) |
| { |
| /* Update the bounds only when there is no previous estimation, or when the |
| current estimation is smaller. */ |
| if (upper |
| && (!loop->any_upper_bound |
| || wi::ltu_p (i_bound, loop->nb_iterations_upper_bound))) |
| { |
| loop->any_upper_bound = true; |
| loop->nb_iterations_upper_bound = i_bound; |
| if (!loop->any_likely_upper_bound) |
| { |
| loop->any_likely_upper_bound = true; |
| loop->nb_iterations_likely_upper_bound = i_bound; |
| } |
| } |
| if (realistic |
| && (!loop->any_estimate |
| || wi::ltu_p (i_bound, loop->nb_iterations_estimate))) |
| { |
| loop->any_estimate = true; |
| loop->nb_iterations_estimate = i_bound; |
| } |
| if (!realistic |
| && (!loop->any_likely_upper_bound |
| || wi::ltu_p (i_bound, loop->nb_iterations_likely_upper_bound))) |
| { |
| loop->any_likely_upper_bound = true; |
| loop->nb_iterations_likely_upper_bound = i_bound; |
| } |
| |
| /* If an upper bound is smaller than the realistic estimate of the |
| number of iterations, use the upper bound instead. */ |
| if (loop->any_upper_bound |
| && loop->any_estimate |
| && wi::ltu_p (loop->nb_iterations_upper_bound, |
| loop->nb_iterations_estimate)) |
| loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; |
| if (loop->any_upper_bound |
| && loop->any_likely_upper_bound |
| && wi::ltu_p (loop->nb_iterations_upper_bound, |
| loop->nb_iterations_likely_upper_bound)) |
| loop->nb_iterations_likely_upper_bound = loop->nb_iterations_upper_bound; |
| } |
| |
| /* Similar to get_estimated_loop_iterations, but returns the estimate only |
| if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
| on the number of iterations of LOOP could not be derived, returns -1. */ |
| |
| HOST_WIDE_INT |
| get_estimated_loop_iterations_int (struct loop *loop) |
| { |
| widest_int nit; |
| HOST_WIDE_INT hwi_nit; |
| |
| if (!get_estimated_loop_iterations (loop, &nit)) |
| return -1; |
| |
| if (!wi::fits_shwi_p (nit)) |
| return -1; |
| hwi_nit = nit.to_shwi (); |
| |
| return hwi_nit < 0 ? -1 : hwi_nit; |
| } |
| |
| /* Returns an upper bound on the number of executions of statements |
| in the LOOP. For statements before the loop exit, this exceeds |
| the number of execution of the latch by one. */ |
| |
| HOST_WIDE_INT |
| max_stmt_executions_int (struct loop *loop) |
| { |
| HOST_WIDE_INT nit = get_max_loop_iterations_int (loop); |
| HOST_WIDE_INT snit; |
| |
| if (nit == -1) |
| return -1; |
| |
| snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); |
| |
| /* If the computation overflows, return -1. */ |
| return snit < 0 ? -1 : snit; |
| } |
| |
| /* Returns an likely upper bound on the number of executions of statements |
| in the LOOP. For statements before the loop exit, this exceeds |
| the number of execution of the latch by one. */ |
| |
| HOST_WIDE_INT |
| likely_max_stmt_executions_int (struct loop *loop) |
| { |
| HOST_WIDE_INT nit = get_likely_max_loop_iterations_int (loop); |
| HOST_WIDE_INT snit; |
| |
| if (nit == -1) |
| return -1; |
| |
| snit = (HOST_WIDE_INT) ((unsigned HOST_WIDE_INT) nit + 1); |
| |
| /* If the computation overflows, return -1. */ |
| return snit < 0 ? -1 : snit; |
| } |
| |
| /* Sets NIT to the estimated number of executions of the latch of the |
| LOOP. If we have no reliable estimate, the function returns false, otherwise |
| returns true. */ |
| |
| bool |
| get_estimated_loop_iterations (struct loop *loop, widest_int *nit) |
| { |
| /* Even if the bound is not recorded, possibly we can derrive one from |
| profile. */ |
| if (!loop->any_estimate) |
| { |
| if (loop->header->count) |
| { |
| *nit = gcov_type_to_wide_int |
| (expected_loop_iterations_unbounded (loop) + 1); |
| return true; |
| } |
| return false; |
| } |
| |
| *nit = loop->nb_iterations_estimate; |
| return true; |
| } |
| |
| /* Sets NIT to an upper bound for the maximum number of executions of the |
| latch of the LOOP. If we have no reliable estimate, the function returns |
| false, otherwise returns true. */ |
| |
| bool |
| get_max_loop_iterations (const struct loop *loop, widest_int *nit) |
| { |
| if (!loop->any_upper_bound) |
| return false; |
| |
| *nit = loop->nb_iterations_upper_bound; |
| return true; |
| } |
| |
| /* Similar to get_max_loop_iterations, but returns the estimate only |
| if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
| on the number of iterations of LOOP could not be derived, returns -1. */ |
| |
| HOST_WIDE_INT |
| get_max_loop_iterations_int (const struct loop *loop) |
| { |
| widest_int nit; |
| HOST_WIDE_INT hwi_nit; |
| |
| if (!get_max_loop_iterations (loop, &nit)) |
| return -1; |
| |
| if (!wi::fits_shwi_p (nit)) |
| return -1; |
| hwi_nit = nit.to_shwi (); |
| |
| return hwi_nit < 0 ? -1 : hwi_nit; |
| } |
| |
| /* Sets NIT to an upper bound for the maximum number of executions of the |
| latch of the LOOP. If we have no reliable estimate, the function returns |
| false, otherwise returns true. */ |
| |
| bool |
| get_likely_max_loop_iterations (struct loop *loop, widest_int *nit) |
| { |
| if (!loop->any_likely_upper_bound) |
| return false; |
| |
| *nit = loop->nb_iterations_likely_upper_bound; |
| return true; |
| } |
| |
| /* Similar to get_max_loop_iterations, but returns the estimate only |
| if it fits to HOST_WIDE_INT. If this is not the case, or the estimate |
| on the number of iterations of LOOP could not be derived, returns -1. */ |
| |
| HOST_WIDE_INT |
| get_likely_max_loop_iterations_int (struct loop *loop) |
| { |
| widest_int nit; |
| HOST_WIDE_INT hwi_nit; |
| |
| if (!get_likely_max_loop_iterations (loop, &nit)) |
| return -1; |
| |
| if (!wi::fits_shwi_p (nit)) |
| return -1; |
| hwi_nit = nit.to_shwi (); |
| |
| return hwi_nit < 0 ? -1 : hwi_nit; |
| } |
| |
| /* Returns the loop depth of the loop BB belongs to. */ |
| |
| int |
| bb_loop_depth (const_basic_block bb) |
| { |
| return bb->loop_father ? loop_depth (bb->loop_father) : 0; |
| } |
| |
| /* Marks LOOP for removal and sets LOOPS_NEED_FIXUP. */ |
| |
| void |
| mark_loop_for_removal (loop_p loop) |
| { |
| if (loop->header == NULL) |
| return; |
| loop->former_header = loop->header; |
| loop->header = NULL; |
| loop->latch = NULL; |
| loops_state_set (LOOPS_NEED_FIXUP); |
| } |