diff options
Diffstat (limited to 'gcc/tree-outof-ssa.c')
| -rw-r--r-- | gcc/tree-outof-ssa.c | 1104 |
1 files changed, 266 insertions, 838 deletions
diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c index 19e49d5..59958f5 100644 --- a/gcc/tree-outof-ssa.c +++ b/gcc/tree-outof-ssa.c @@ -30,9 +30,10 @@ along with GCC; see the file COPYING3. If not see #include "tree-flow.h" #include "timevar.h" #include "tree-dump.h" -#include "tree-ssa-live.h" #include "tree-pass.h" #include "toplev.h" +#include "expr.h" +#include "ssaexpand.h" /* Used to hold all the components required to do SSA PHI elimination. @@ -61,7 +62,7 @@ typedef struct _elim_graph { int size; /* List of nodes in the elimination graph. */ - VEC(tree,heap) *nodes; + VEC(int,heap) *nodes; /* The predecessor and successor edge list. */ VEC(int,heap) *edge_list; @@ -79,85 +80,176 @@ typedef struct _elim_graph { edge e; /* List of constant copies to emit. These are pushed on in pairs. */ + VEC(int,heap) *const_dests; VEC(tree,heap) *const_copies; } *elim_graph; -/* Create a temporary variable based on the type of variable T. Use T's name - as the prefix. */ +/* For an edge E find out a good source location to associate with + instructions inserted on edge E. If E has an implicit goto set, + use its location. Otherwise search instructions in predecessors + of E for a location, and use that one. That makes sense because + we insert on edges for PHI nodes, and effects of PHIs happen on + the end of the predecessor conceptually. */ -static tree -create_temp (tree t) +static void +set_location_for_edge (edge e) { - tree tmp; - const char *name = NULL; - tree type; - - if (TREE_CODE (t) == SSA_NAME) - t = SSA_NAME_VAR (t); - - gcc_assert (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == PARM_DECL); + if (e->goto_locus) + { + set_curr_insn_source_location (e->goto_locus); + set_curr_insn_block (e->goto_block); + } + else + { + basic_block bb = e->src; + gimple_stmt_iterator gsi; - type = TREE_TYPE (t); - tmp = DECL_NAME (t); - if (tmp) - name = IDENTIFIER_POINTER (tmp); + do + { + for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + if (gimple_has_location (stmt) || gimple_block (stmt)) + { + set_curr_insn_source_location (gimple_location (stmt)); + set_curr_insn_block (gimple_block (stmt)); + return; + } + } + /* Nothing found in this basic block. Make a half-assed attempt + to continue with another block. */ + if (single_pred_p (bb)) + bb = single_pred (bb); + else + bb = e->src; + } + while (bb != e->src); + } +} - if (name == NULL) - name = "temp"; - tmp = create_tmp_var (type, name); +/* Insert a copy instruction from partition SRC to DEST onto edge E. */ - if (DECL_DEBUG_EXPR_IS_FROM (t) && DECL_DEBUG_EXPR (t)) +static void +insert_partition_copy_on_edge (edge e, int dest, int src) +{ + rtx seq; + if (dump_file && (dump_flags & TDF_DETAILS)) { - SET_DECL_DEBUG_EXPR (tmp, DECL_DEBUG_EXPR (t)); - DECL_DEBUG_EXPR_IS_FROM (tmp) = 1; + fprintf (dump_file, + "Inserting a partition copy on edge BB%d->BB%d :" + "PART.%d = PART.%d", + e->src->index, + e->dest->index, dest, src); + fprintf (dump_file, "\n"); } - else if (!DECL_IGNORED_P (t)) + + gcc_assert (SA.partition_to_pseudo[dest]); + gcc_assert (SA.partition_to_pseudo[src]); + + set_location_for_edge (e); + + /* Partition copy between same base variables only, so it's the same mode, + hence we can use emit_move_insn. */ + start_sequence (); + emit_move_insn (SA.partition_to_pseudo[dest], SA.partition_to_pseudo[src]); + seq = get_insns (); + end_sequence (); + + insert_insn_on_edge (seq, e); +} + +/* Insert a copy instruction from expression SRC to partition DEST + onto edge E. */ + +static void +insert_value_copy_on_edge (edge e, int dest, tree src) +{ + rtx seq, x; + enum machine_mode mode; + if (dump_file && (dump_flags & TDF_DETAILS)) { - SET_DECL_DEBUG_EXPR (tmp, t); - DECL_DEBUG_EXPR_IS_FROM (tmp) = 1; + fprintf (dump_file, + "Inserting a value copy on edge BB%d->BB%d : PART.%d = ", + e->src->index, + e->dest->index, dest); + print_generic_expr (dump_file, src, TDF_SLIM); + fprintf (dump_file, "\n"); } - DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t); - DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t); - DECL_GIMPLE_REG_P (tmp) = DECL_GIMPLE_REG_P (t); - add_referenced_var (tmp); - /* We should never have copied variables in non-automatic storage - or variables that have their address taken. So it is pointless - to try to copy call-clobber state here. */ - gcc_assert (!may_be_aliased (t) && !is_global_var (t)); + gcc_assert (SA.partition_to_pseudo[dest]); - return tmp; -} + set_location_for_edge (e); + + start_sequence (); + mode = GET_MODE (SA.partition_to_pseudo[dest]); + x = expand_expr (src, SA.partition_to_pseudo[dest], mode, EXPAND_NORMAL); + if (GET_MODE (x) != mode) + x = convert_to_mode (mode, x, TYPE_UNSIGNED (TREE_TYPE (src))); + if (x != SA.partition_to_pseudo[dest]) + emit_move_insn (SA.partition_to_pseudo[dest], x); + seq = get_insns (); + end_sequence (); + insert_insn_on_edge (seq, e); +} -/* This helper function fill insert a copy from a constant or variable SRC to - variable DEST on edge E. */ +/* Insert a copy instruction from RTL expression SRC to partition DEST + onto edge E. */ static void -insert_copy_on_edge (edge e, tree dest, tree src) +insert_rtx_to_part_on_edge (edge e, int dest, rtx src) { - gimple copy; + rtx seq; + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, + "Inserting a temp copy on edge BB%d->BB%d : PART.%d = ", + e->src->index, + e->dest->index, dest); + print_simple_rtl (dump_file, src); + fprintf (dump_file, "\n"); + } - copy = gimple_build_assign (dest, src); - set_is_used (dest); + gcc_assert (SA.partition_to_pseudo[dest]); + set_location_for_edge (e); - if (TREE_CODE (src) == ADDR_EXPR) - src = TREE_OPERAND (src, 0); - if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL) - set_is_used (src); + start_sequence (); + gcc_assert (GET_MODE (src) == GET_MODE (SA.partition_to_pseudo[dest])); + emit_move_insn (SA.partition_to_pseudo[dest], src); + seq = get_insns (); + end_sequence (); + insert_insn_on_edge (seq, e); +} + +/* Insert a copy instruction from partition SRC to RTL lvalue DEST + onto edge E. */ + +static void +insert_part_to_rtx_on_edge (edge e, rtx dest, int src) +{ + rtx seq; if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, - "Inserting a copy on edge BB%d->BB%d :", + "Inserting a temp copy on edge BB%d->BB%d : ", e->src->index, e->dest->index); - print_gimple_stmt (dump_file, copy, 0, dump_flags); - fprintf (dump_file, "\n"); + print_simple_rtl (dump_file, dest); + fprintf (dump_file, "= PART.%d\n", src); } - gsi_insert_on_edge (e, copy); + gcc_assert (SA.partition_to_pseudo[src]); + set_location_for_edge (e); + + start_sequence (); + gcc_assert (GET_MODE (dest) == GET_MODE (SA.partition_to_pseudo[src])); + emit_move_insn (dest, SA.partition_to_pseudo[src]); + seq = get_insns (); + end_sequence (); + + insert_insn_on_edge (seq, e); } @@ -169,7 +261,8 @@ new_elim_graph (int size) { elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph)); - g->nodes = VEC_alloc (tree, heap, 30); + g->nodes = VEC_alloc (int, heap, 30); + g->const_dests = VEC_alloc (int, heap, 20); g->const_copies = VEC_alloc (tree, heap, 20); g->edge_list = VEC_alloc (int, heap, 20); g->stack = VEC_alloc (int, heap, 30); @@ -185,7 +278,7 @@ new_elim_graph (int size) static inline void clear_elim_graph (elim_graph g) { - VEC_truncate (tree, g->nodes, 0); + VEC_truncate (int, g->nodes, 0); VEC_truncate (int, g->edge_list, 0); } @@ -199,7 +292,8 @@ delete_elim_graph (elim_graph g) VEC_free (int, heap, g->stack); VEC_free (int, heap, g->edge_list); VEC_free (tree, heap, g->const_copies); - VEC_free (tree, heap, g->nodes); + VEC_free (int, heap, g->const_dests); + VEC_free (int, heap, g->nodes); free (g); } @@ -209,22 +303,22 @@ delete_elim_graph (elim_graph g) static inline int elim_graph_size (elim_graph g) { - return VEC_length (tree, g->nodes); + return VEC_length (int, g->nodes); } /* Add NODE to graph G, if it doesn't exist already. */ static inline void -elim_graph_add_node (elim_graph g, tree node) +elim_graph_add_node (elim_graph g, int node) { int x; - tree t; + int t; - for (x = 0; VEC_iterate (tree, g->nodes, x, t); x++) + for (x = 0; VEC_iterate (int, g->nodes, x, t); x++) if (t == node) return; - VEC_safe_push (tree, heap, g->nodes, node); + VEC_safe_push (int, heap, g->nodes, node); } @@ -299,7 +393,7 @@ do { \ /* Add T to elimination graph G. */ static inline void -eliminate_name (elim_graph g, tree T) +eliminate_name (elim_graph g, int T) { elim_graph_add_node (g, T); } @@ -309,22 +403,21 @@ eliminate_name (elim_graph g, tree T) G->e. */ static void -eliminate_build (elim_graph g, basic_block B) +eliminate_build (elim_graph g) { - tree T0, Ti; + tree Ti; int p0, pi; gimple_stmt_iterator gsi; clear_elim_graph (g); - for (gsi = gsi_start_phis (B); !gsi_end_p (gsi); gsi_next (&gsi)) + for (gsi = gsi_start_phis (g->e->dest); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple phi = gsi_stmt (gsi); - T0 = var_to_partition_to_var (g->map, gimple_phi_result (phi)); - + p0 = var_to_partition (g->map, gimple_phi_result (phi)); /* Ignore results which are not in partitions. */ - if (T0 == NULL_TREE) + if (p0 == NO_PARTITION) continue; Ti = PHI_ARG_DEF (phi, g->e->dest_idx); @@ -338,18 +431,16 @@ eliminate_build (elim_graph g, basic_block B) { /* Save constant copies until all other copies have been emitted on this edge. */ - VEC_safe_push (tree, heap, g->const_copies, T0); + VEC_safe_push (int, heap, g->const_dests, p0); VEC_safe_push (tree, heap, g->const_copies, Ti); } else { - Ti = var_to_partition_to_var (g->map, Ti); - if (T0 != Ti) + pi = var_to_partition (g->map, Ti); + if (p0 != pi) { - eliminate_name (g, T0); - eliminate_name (g, Ti); - p0 = var_to_partition (g->map, T0); - pi = var_to_partition (g->map, Ti); + eliminate_name (g, p0); + eliminate_name (g, pi); elim_graph_add_edge (g, p0, pi); } } @@ -399,32 +490,46 @@ elim_backward (elim_graph g, int T) if (!TEST_BIT (g->visited, P)) { elim_backward (g, P); - insert_copy_on_edge (g->e, - partition_to_var (g->map, P), - partition_to_var (g->map, T)); + insert_partition_copy_on_edge (g->e, P, T); } }); } +/* Allocate a new pseudo register usable for storing values sitting + in NAME (a decl or SSA name), i.e. with matching mode and attributes. */ + +static rtx +get_temp_reg (tree name) +{ + tree var = TREE_CODE (name) == SSA_NAME ? SSA_NAME_VAR (name) : name; + tree type = TREE_TYPE (var); + int unsignedp = TYPE_UNSIGNED (type); + enum machine_mode reg_mode + = promote_mode (type, DECL_MODE (var), &unsignedp, 0); + rtx x = gen_reg_rtx (reg_mode); + if (POINTER_TYPE_P (type)) + mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (var)))); + return x; +} + /* Insert required copies for T in graph G. Check for a strongly connected region, and create a temporary to break the cycle if one is found. */ static void elim_create (elim_graph g, int T) { - tree U; int P, S; if (elim_unvisited_predecessor (g, T)) { - U = create_temp (partition_to_var (g->map, T)); - insert_copy_on_edge (g->e, U, partition_to_var (g->map, T)); + rtx U = get_temp_reg (partition_to_var (g->map, T)); + insert_part_to_rtx_on_edge (g->e, U, T); FOR_EACH_ELIM_GRAPH_PRED (g, T, P, { if (!TEST_BIT (g->visited, P)) { elim_backward (g, P); - insert_copy_on_edge (g->e, partition_to_var (g->map, P), U); + insert_rtx_to_part_on_edge (g->e, P, U); } }); } @@ -434,12 +539,9 @@ elim_create (elim_graph g, int T) if (S != -1) { SET_BIT (g->visited, T); - insert_copy_on_edge (g->e, - partition_to_var (g->map, T), - partition_to_var (g->map, S)); + insert_partition_copy_on_edge (g->e, T, S); } } - } @@ -449,7 +551,6 @@ static void eliminate_phi (edge e, elim_graph g) { int x; - basic_block B = e->dest; gcc_assert (VEC_length (tree, g->const_copies) == 0); @@ -459,20 +560,19 @@ eliminate_phi (edge e, elim_graph g) g->e = e; - eliminate_build (g, B); + eliminate_build (g); if (elim_graph_size (g) != 0) { - tree var; + int part; sbitmap_zero (g->visited); VEC_truncate (int, g->stack, 0); - for (x = 0; VEC_iterate (tree, g->nodes, x, var); x++) + for (x = 0; VEC_iterate (int, g->nodes, x, part); x++) { - int p = var_to_partition (g->map, var); - if (!TEST_BIT (g->visited, p)) - elim_forward (g, p); + if (!TEST_BIT (g->visited, part)) + elim_forward (g, part); } sbitmap_zero (g->visited); @@ -487,121 +587,15 @@ eliminate_phi (edge e, elim_graph g) /* If there are any pending constant copies, issue them now. */ while (VEC_length (tree, g->const_copies) > 0) { - tree src, dest; + int dest; + tree src; src = VEC_pop (tree, g->const_copies); - dest = VEC_pop (tree, g->const_copies); - insert_copy_on_edge (e, dest, src); + dest = VEC_pop (int, g->const_dests); + insert_value_copy_on_edge (e, dest, src); } } -/* Take the ssa-name var_map MAP, and assign real variables to each - partition. */ - -static void -assign_vars (var_map map) -{ - int x, num; - tree var, root; - var_ann_t ann; - - num = num_var_partitions (map); - for (x = 0; x < num; x++) - { - var = partition_to_var (map, x); - if (TREE_CODE (var) != SSA_NAME) - { - ann = var_ann (var); - /* It must already be coalesced. */ - gcc_assert (ann->out_of_ssa_tag == 1); - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "partition %d already has variable ", x); - print_generic_expr (dump_file, var, TDF_SLIM); - fprintf (dump_file, " assigned to it.\n"); - } - } - else - { - root = SSA_NAME_VAR (var); - ann = var_ann (root); - /* If ROOT is already associated, create a new one. */ - if (ann->out_of_ssa_tag) - { - root = create_temp (root); - ann = var_ann (root); - } - /* ROOT has not been coalesced yet, so use it. */ - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Partition %d is assigned to var ", x); - print_generic_stmt (dump_file, root, TDF_SLIM); - } - change_partition_var (map, root, x); - } - } -} - - -/* Replace use operand P with whatever variable it has been rewritten to based - on the partitions in MAP. EXPR is an optional expression vector over SSA - versions which is used to replace P with an expression instead of a variable. - If the stmt is changed, return true. */ - -static inline bool -replace_use_variable (var_map map, use_operand_p p, gimple *expr) -{ - tree new_var; - tree var = USE_FROM_PTR (p); - - /* Check if we are replacing this variable with an expression. */ - if (expr) - { - int version = SSA_NAME_VERSION (var); - if (expr[version]) - { - SET_USE (p, gimple_assign_rhs_to_tree (expr[version])); - return true; - } - } - - new_var = var_to_partition_to_var (map, var); - if (new_var) - { - SET_USE (p, new_var); - set_is_used (new_var); - return true; - } - return false; -} - - -/* Replace def operand DEF_P with whatever variable it has been rewritten to - based on the partitions in MAP. EXPR is an optional expression vector over - SSA versions which is used to replace DEF_P with an expression instead of a - variable. If the stmt is changed, return true. */ - -static inline bool -replace_def_variable (var_map map, def_operand_p def_p, tree *expr) -{ - tree new_var; - tree var = DEF_FROM_PTR (def_p); - - /* Do nothing if we are replacing this variable with an expression. */ - if (expr && expr[SSA_NAME_VERSION (var)]) - return true; - - new_var = var_to_partition_to_var (map, var); - if (new_var) - { - SET_DEF (def_p, new_var); - set_is_used (new_var); - return true; - } - return false; -} - - /* Remove each argument from PHI. If an arg was the last use of an SSA_NAME, check to see if this allows another PHI node to be removed. */ @@ -704,21 +698,16 @@ eliminate_useless_phis (void) variable. */ static void -rewrite_trees (var_map map, gimple *values) +rewrite_trees (var_map map) { - elim_graph g; - basic_block bb; - gimple_stmt_iterator gsi; - edge e; - gimple_seq phi; - bool changed; - #ifdef ENABLE_CHECKING + basic_block bb; /* Search for PHIs where the destination has no partition, but one or more arguments has a partition. This should not happen and can create incorrect code. */ FOR_EACH_BB (bb) { + gimple_stmt_iterator gsi; for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple phi = gsi_stmt (gsi); @@ -744,593 +733,54 @@ rewrite_trees (var_map map, gimple *values) } } #endif - - /* Replace PHI nodes with any required copies. */ - g = new_elim_graph (map->num_partitions); - g->map = map; - FOR_EACH_BB (bb) - { - for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) - { - gimple stmt = gsi_stmt (gsi); - use_operand_p use_p, copy_use_p; - def_operand_p def_p; - bool remove = false, is_copy = false; - int num_uses = 0; - ssa_op_iter iter; - - changed = false; - - if (gimple_assign_copy_p (stmt)) - is_copy = true; - - copy_use_p = NULL_USE_OPERAND_P; - FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) - { - if (replace_use_variable (map, use_p, values)) - changed = true; - copy_use_p = use_p; - num_uses++; - } - - if (num_uses != 1) - is_copy = false; - - def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF); - - if (def_p != NULL) - { - /* Mark this stmt for removal if it is the list of replaceable - expressions. */ - if (values && values[SSA_NAME_VERSION (DEF_FROM_PTR (def_p))]) - remove = true; - else - { - if (replace_def_variable (map, def_p, NULL)) - changed = true; - /* If both SSA_NAMEs coalesce to the same variable, - mark the now redundant copy for removal. */ - if (is_copy) - { - gcc_assert (copy_use_p != NULL_USE_OPERAND_P); - if (DEF_FROM_PTR (def_p) == USE_FROM_PTR (copy_use_p)) - remove = true; - } - } - } - else - FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF) - if (replace_def_variable (map, def_p, NULL)) - changed = true; - - /* Remove any stmts marked for removal. */ - if (remove) - gsi_remove (&gsi, true); - else - { - if (changed) - if (maybe_clean_or_replace_eh_stmt (stmt, stmt)) - gimple_purge_dead_eh_edges (bb); - gsi_next (&gsi); - } - } - - phi = phi_nodes (bb); - if (phi) - { - edge_iterator ei; - FOR_EACH_EDGE (e, ei, bb->preds) - eliminate_phi (e, g); - } - } - - delete_elim_graph (g); -} - -/* These are the local work structures used to determine the best place to - insert the copies that were placed on edges by the SSA->normal pass.. */ -static VEC(edge,heap) *edge_leader; -static VEC(gimple_seq,heap) *stmt_list; -static bitmap leader_has_match = NULL; -static edge leader_match = NULL; - - -/* Pass this function to make_forwarder_block so that all the edges with - matching PENDING_STMT lists to 'curr_stmt_list' get redirected. E is the - edge to test for a match. */ - -static inline bool -same_stmt_list_p (edge e) -{ - return (e->aux == (PTR) leader_match) ? true : false; } +/* Given the out-of-ssa info object SA (with prepared partitions) + eliminate all phi nodes in all basic blocks. Afterwards no + basic block will have phi nodes anymore and there are possibly + some RTL instructions inserted on edges. */ -/* Return TRUE if S1 and S2 are equivalent copies. */ - -static inline bool -identical_copies_p (const_gimple s1, const_gimple s2) -{ -#ifdef ENABLE_CHECKING - gcc_assert (is_gimple_assign (s1)); - gcc_assert (is_gimple_assign (s2)); - gcc_assert (DECL_P (gimple_assign_lhs (s1))); - gcc_assert (DECL_P (gimple_assign_lhs (s2))); -#endif - - if (gimple_assign_lhs (s1) != gimple_assign_lhs (s2)) - return false; - - if (gimple_assign_rhs1 (s1) != gimple_assign_rhs1 (s2)) - return false; - - return true; -} - - -/* Compare the PENDING_STMT list for edges E1 and E2. Return true if the lists - contain the same sequence of copies. */ - -static inline bool -identical_stmt_lists_p (const_edge e1, const_edge e2) -{ - gimple_seq t1 = PENDING_STMT (e1); - gimple_seq t2 = PENDING_STMT (e2); - gimple_stmt_iterator gsi1, gsi2; - - for (gsi1 = gsi_start (t1), gsi2 = gsi_start (t2); - !gsi_end_p (gsi1) && !gsi_end_p (gsi2); - gsi_next (&gsi1), gsi_next (&gsi2)) - { - if (!identical_copies_p (gsi_stmt (gsi1), gsi_stmt (gsi2))) - break; - } - - if (!gsi_end_p (gsi1) || !gsi_end_p (gsi2)) - return false; - - return true; -} - - -/* Allocate data structures used in analyze_edges_for_bb. */ - -static void -init_analyze_edges_for_bb (void) -{ - edge_leader = VEC_alloc (edge, heap, 25); - stmt_list = VEC_alloc (gimple_seq, heap, 25); - leader_has_match = BITMAP_ALLOC (NULL); -} - - -/* Free data structures used in analyze_edges_for_bb. */ - -static void -fini_analyze_edges_for_bb (void) -{ - VEC_free (edge, heap, edge_leader); - VEC_free (gimple_seq, heap, stmt_list); - BITMAP_FREE (leader_has_match); -} - -/* A helper function to be called via walk_tree. Return DATA if it is - contained in subtree TP. */ - -static tree -contains_tree_r (tree * tp, int *walk_subtrees, void *data) -{ - if (*tp == data) - { - *walk_subtrees = 0; - return (tree) data; - } - else - return NULL_TREE; -} - -/* A threshold for the number of insns contained in the latch block. - It is used to prevent blowing the loop with too many copies from - the latch. */ -#define MAX_STMTS_IN_LATCH 2 - -/* Return TRUE if the stmts on SINGLE-EDGE can be moved to the - body of the loop. This should be permitted only if SINGLE-EDGE is a - single-basic-block latch edge and thus cleaning the latch will help - to create a single-basic-block loop. Otherwise return FALSE. */ - -static bool -process_single_block_loop_latch (edge single_edge) -{ - gimple_seq stmts; - basic_block b_exit, b_pheader, b_loop = single_edge->src; - edge_iterator ei; - edge e; - gimple_stmt_iterator gsi, gsi_exit; - gimple_stmt_iterator tsi; - tree expr; - gimple stmt; - unsigned int count = 0; - - if (single_edge == NULL || (single_edge->dest != single_edge->src) - || (EDGE_COUNT (b_loop->succs) != 2) - || (EDGE_COUNT (b_loop->preds) != 2)) - return false; - - /* Get the stmts on the latch edge. */ - stmts = PENDING_STMT (single_edge); - - /* Find the successor edge which is not the latch edge. */ - FOR_EACH_EDGE (e, ei, b_loop->succs) - if (e->dest != b_loop) - break; - - b_exit = e->dest; - - /* Check that the exit block has only the loop as a predecessor, - and that there are no pending stmts on that edge as well. */ - if (EDGE_COUNT (b_exit->preds) != 1 || PENDING_STMT (e)) - return false; - - /* Find the predecessor edge which is not the latch edge. */ - FOR_EACH_EDGE (e, ei, b_loop->preds) - if (e->src != b_loop) - break; - - b_pheader = e->src; - - if (b_exit == b_pheader || b_exit == b_loop || b_pheader == b_loop) - return false; - - gsi_exit = gsi_after_labels (b_exit); - - /* Get the last stmt in the loop body. */ - gsi = gsi_last_bb (single_edge->src); - stmt = gsi_stmt (gsi); - - if (gimple_code (stmt) != GIMPLE_COND) - return false; - - - expr = build2 (gimple_cond_code (stmt), boolean_type_node, - gimple_cond_lhs (stmt), gimple_cond_rhs (stmt)); - /* Iterate over the insns on the latch and count them. */ - for (tsi = gsi_start (stmts); !gsi_end_p (tsi); gsi_next (&tsi)) - { - gimple stmt1 = gsi_stmt (tsi); - tree var; - - count++; - /* Check that the condition does not contain any new definition - created in the latch as the stmts from the latch intended - to precede it. */ - if (gimple_code (stmt1) != GIMPLE_ASSIGN) - return false; - var = gimple_assign_lhs (stmt1); - if (TREE_THIS_VOLATILE (var) - || TYPE_VOLATILE (TREE_TYPE (var)) - || walk_tree (&expr, contains_tree_r, var, NULL)) - return false; - } - /* Check that the latch does not contain more than MAX_STMTS_IN_LATCH - insns. The purpose of this restriction is to prevent blowing the - loop with too many copies from the latch. */ - if (count > MAX_STMTS_IN_LATCH) - return false; - - /* Apply the transformation - clean up the latch block: - - var = something; - L1: - x1 = expr; - if (cond) goto L2 else goto L3; - L2: - var = x1; - goto L1 - L3: - ... - - ==> - - var = something; - L1: - x1 = expr; - tmp_var = var; - var = x1; - if (cond) goto L1 else goto L2; - L2: - var = tmp_var; - ... - */ - for (tsi = gsi_start (stmts); !gsi_end_p (tsi); gsi_next (&tsi)) - { - gimple stmt1 = gsi_stmt (tsi); - tree var, tmp_var; - gimple copy; - - /* Create a new variable to load back the value of var in case - we exit the loop. */ - var = gimple_assign_lhs (stmt1); - tmp_var = create_temp (var); - copy = gimple_build_assign (tmp_var, var); - set_is_used (tmp_var); - gsi_insert_before (&gsi, copy, GSI_SAME_STMT); - copy = gimple_build_assign (var, tmp_var); - gsi_insert_before (&gsi_exit, copy, GSI_SAME_STMT); - } - - PENDING_STMT (single_edge) = 0; - /* Insert the new stmts to the loop body. */ - gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT); - - if (dump_file) - fprintf (dump_file, - "\nCleaned-up latch block of loop with single BB: %d\n\n", - single_edge->dest->index); - - return true; -} - -/* Look at all the incoming edges to block BB, and decide where the best place - to insert the stmts on each edge are, and perform those insertions. */ - -static void -analyze_edges_for_bb (basic_block bb) -{ - edge e; - edge_iterator ei; - int count; - unsigned int x; - bool have_opportunity; - gimple_stmt_iterator gsi; - gimple stmt; - edge single_edge = NULL; - bool is_label; - edge leader; - - count = 0; - - /* Blocks which contain at least one abnormal edge cannot use - make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs - found on edges in these block. */ - have_opportunity = true; - FOR_EACH_EDGE (e, ei, bb->preds) - if (e->flags & EDGE_ABNORMAL) - { - have_opportunity = false; - break; - } - - if (!have_opportunity) - { - FOR_EACH_EDGE (e, ei, bb->preds) - if (PENDING_STMT (e)) - gsi_commit_one_edge_insert (e, NULL); - return; - } - - /* Find out how many edges there are with interesting pending stmts on them. - Commit the stmts on edges we are not interested in. */ - FOR_EACH_EDGE (e, ei, bb->preds) - { - if (PENDING_STMT (e)) - { - gcc_assert (!(e->flags & EDGE_ABNORMAL)); - if (e->flags & EDGE_FALLTHRU) - { - gsi = gsi_start_bb (e->src); - if (!gsi_end_p (gsi)) - { - stmt = gsi_stmt (gsi); - gsi_next (&gsi); - gcc_assert (stmt != NULL); - is_label = (gimple_code (stmt) == GIMPLE_LABEL); - /* Punt if it has non-label stmts, or isn't local. */ - if (!is_label - || DECL_NONLOCAL (gimple_label_label (stmt)) - || !gsi_end_p (gsi)) - { - gsi_commit_one_edge_insert (e, NULL); - continue; - } - } - } - single_edge = e; - count++; - } - } - - /* If there aren't at least 2 edges, no sharing will happen. */ - if (count < 2) - { - if (single_edge) - { - /* Add stmts to the edge unless processed specially as a - single-block loop latch edge. */ - if (!process_single_block_loop_latch (single_edge)) - gsi_commit_one_edge_insert (single_edge, NULL); - } - return; - } - - /* Ensure that we have empty worklists. */ -#ifdef ENABLE_CHECKING - gcc_assert (VEC_length (edge, edge_leader) == 0); - gcc_assert (VEC_length (gimple_seq, stmt_list) == 0); - gcc_assert (bitmap_empty_p (leader_has_match)); -#endif - - /* Find the "leader" block for each set of unique stmt lists. Preference is - given to FALLTHRU blocks since they would need a GOTO to arrive at another - block. The leader edge destination is the block which all the other edges - with the same stmt list will be redirected to. */ - have_opportunity = false; - FOR_EACH_EDGE (e, ei, bb->preds) - { - if (PENDING_STMT (e)) - { - bool found = false; - - /* Look for the same stmt list in edge leaders list. */ - for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++) - { - if (identical_stmt_lists_p (leader, e)) - { - /* Give this edge the same stmt list pointer. */ - PENDING_STMT (e) = NULL; - e->aux = leader; - bitmap_set_bit (leader_has_match, x); - have_opportunity = found = true; - break; - } - } - - /* If no similar stmt list, add this edge to the leader list. */ - if (!found) - { - VEC_safe_push (edge, heap, edge_leader, e); - VEC_safe_push (gimple_seq, heap, stmt_list, PENDING_STMT (e)); - } - } - } - - /* If there are no similar lists, just issue the stmts. */ - if (!have_opportunity) - { - for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++) - gsi_commit_one_edge_insert (leader, NULL); - VEC_truncate (edge, edge_leader, 0); - VEC_truncate (gimple_seq, stmt_list, 0); - bitmap_clear (leader_has_match); - return; - } - - if (dump_file) - fprintf (dump_file, "\nOpportunities in BB %d for stmt/block reduction:\n", - bb->index); - - /* For each common list, create a forwarding block and issue the stmt's - in that block. */ - for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++) - if (bitmap_bit_p (leader_has_match, x)) - { - edge new_edge; - gimple_stmt_iterator gsi; - gimple_seq curr_stmt_list; - - leader_match = leader; - - /* The tree_* cfg manipulation routines use the PENDING_EDGE field - for various PHI manipulations, so it gets cleared when calls are - made to make_forwarder_block(). So make sure the edge is clear, - and use the saved stmt list. */ - PENDING_STMT (leader) = NULL; - leader->aux = leader; - curr_stmt_list = VEC_index (gimple_seq, stmt_list, x); - - new_edge = make_forwarder_block (leader->dest, same_stmt_list_p, - NULL); - bb = new_edge->dest; - if (dump_file) - { - fprintf (dump_file, "Splitting BB %d for Common stmt list. ", - leader->dest->index); - fprintf (dump_file, "Original block is now BB%d.\n", bb->index); - print_gimple_seq (dump_file, curr_stmt_list, 0, TDF_VOPS); - } - - FOR_EACH_EDGE (e, ei, new_edge->src->preds) - { - e->aux = NULL; - if (dump_file) - fprintf (dump_file, " Edge (%d->%d) lands here.\n", - e->src->index, e->dest->index); - } - - gsi = gsi_last_bb (leader->dest); - gsi_insert_seq_after (&gsi, curr_stmt_list, GSI_NEW_STMT); - - leader_match = NULL; - /* We should never get a new block now. */ - } - else - { - PENDING_STMT (leader) = VEC_index (gimple_seq, stmt_list, x); - gsi_commit_one_edge_insert (leader, NULL); - } - - - /* Clear the working data structures. */ - VEC_truncate (edge, edge_leader, 0); - VEC_truncate (gimple_seq, stmt_list, 0); - bitmap_clear (leader_has_match); -} - - -/* This function will analyze the insertions which were performed on edges, - and decide whether they should be left on that edge, or whether it is more - efficient to emit some subset of them in a single block. All stmts are - inserted somewhere. */ - -static void -perform_edge_inserts (void) +void +expand_phi_nodes (struct ssaexpand *sa) { basic_block bb; + elim_graph g = new_elim_graph (sa->map->num_partitions); + g->map = sa->map; - if (dump_file) - fprintf(dump_file, "Analyzing Edge Insertions.\n"); - - /* analyze_edges_for_bb calls make_forwarder_block, which tries to - incrementally update the dominator information. Since we don't - need dominator information after this pass, go ahead and free the - dominator information. */ - free_dominance_info (CDI_DOMINATORS); - free_dominance_info (CDI_POST_DOMINATORS); - - /* Allocate data structures used in analyze_edges_for_bb. */ - init_analyze_edges_for_bb (); - - FOR_EACH_BB (bb) - analyze_edges_for_bb (bb); - - analyze_edges_for_bb (EXIT_BLOCK_PTR); - - /* Free data structures used in analyze_edges_for_bb. */ - fini_analyze_edges_for_bb (); - -#ifdef ENABLE_CHECKING - { - edge_iterator ei; - edge e; - FOR_EACH_BB (bb) + FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR, next_bb) + if (!gimple_seq_empty_p (phi_nodes (bb))) { + edge e; + edge_iterator ei; FOR_EACH_EDGE (e, ei, bb->preds) + eliminate_phi (e, g); + set_phi_nodes (bb, NULL); + /* We can't redirect EH edges in RTL land, so we need to do this + here. Redirection happens only when splitting is necessary, + which it is only for critical edges, normally. For EH edges + it might also be necessary when the successor has more than + one predecessor. In that case the edge is either required to + be fallthru (which EH edges aren't), or the predecessor needs + to end with a jump (which again, isn't the case with EH edges). + Hence, split all EH edges on which we inserted instructions + and whose successor has multiple predecessors. */ + for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); ) { - if (PENDING_STMT (e)) - error (" Pending stmts not issued on PRED edge (%d, %d)\n", - e->src->index, e->dest->index); + if (e->insns.r && (e->flags & EDGE_EH) + && !single_pred_p (e->dest)) + { + rtx insns = e->insns.r; + basic_block bb; + e->insns.r = NULL_RTX; + bb = split_edge (e); + single_pred_edge (bb)->insns.r = insns; + } + else + ei_next (&ei); } - FOR_EACH_EDGE (e, ei, bb->succs) - { - if (PENDING_STMT (e)) - error (" Pending stmts not issued on SUCC edge (%d, %d)\n", - e->src->index, e->dest->index); - } - } - FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs) - { - if (PENDING_STMT (e)) - error (" Pending stmts not issued on ENTRY edge (%d, %d)\n", - e->src->index, e->dest->index); - } - FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds) - { - if (PENDING_STMT (e)) - error (" Pending stmts not issued on EXIT edge (%d, %d)\n", - e->src->index, e->dest->index); } - } -#endif + + delete_elim_graph (g); } @@ -1339,12 +789,11 @@ perform_edge_inserts (void) should also be used. */ static void -remove_ssa_form (bool perform_ter) +remove_ssa_form (bool perform_ter, struct ssaexpand *sa) { - basic_block bb; gimple *values = NULL; var_map map; - gimple_stmt_iterator gsi; + unsigned i; map = coalesce_ssa_name (); @@ -1365,29 +814,21 @@ remove_ssa_form (bool perform_ter) dump_replaceable_exprs (dump_file, values); } - /* Assign real variables to the partitions now. */ - assign_vars (map); + rewrite_trees (map); - if (dump_file && (dump_flags & TDF_DETAILS)) + sa->map = map; + sa->values = values; + sa->partition_has_default_def = BITMAP_ALLOC (NULL); + for (i = 1; i < num_ssa_names; i++) { - fprintf (dump_file, "After Base variable replacement:\n"); - dump_var_map (dump_file, map); + tree t = ssa_name (i); + if (t && SSA_NAME_IS_DEFAULT_DEF (t)) + { + int p = var_to_partition (map, t); + if (p != NO_PARTITION) + bitmap_set_bit (sa->partition_has_default_def, p); + } } - - rewrite_trees (map, values); - - if (values) - free (values); - - /* Remove PHI nodes which have been translated back to real variables. */ - FOR_EACH_BB (bb) - for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);) - remove_phi_node (&gsi, true); - - /* If any copies were inserted on edges, analyze and insert them now. */ - perform_edge_inserts (); - - delete_var_map (map); } @@ -1477,12 +918,26 @@ insert_backedge_copies (void) } } +/* Free all memory associated with going out of SSA form. SA is + the outof-SSA info object. */ + +void +finish_out_of_ssa (struct ssaexpand *sa) +{ + free (sa->partition_to_pseudo); + if (sa->values) + free (sa->values); + delete_var_map (sa->map); + BITMAP_FREE (sa->partition_has_default_def); + memset (sa, 0, sizeof *sa); +} + /* Take the current function out of SSA form, translating PHIs as described in R. Morgan, ``Building an Optimizing Compiler'', Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */ -static unsigned int -rewrite_out_of_ssa (void) +unsigned int +rewrite_out_of_ssa (struct ssaexpand *sa) { /* If elimination of a PHI requires inserting a copy on a backedge, then we will have to split the backedge which has numerous @@ -1499,37 +954,10 @@ rewrite_out_of_ssa (void) if (dump_file && (dump_flags & TDF_DETAILS)) gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS); - remove_ssa_form (flag_tree_ter && !flag_mudflap); + remove_ssa_form (flag_tree_ter, sa); if (dump_file && (dump_flags & TDF_DETAILS)) gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS); - cfun->gimple_df->in_ssa_p = false; return 0; } - - -/* Define the parameters of the out of SSA pass. */ - -struct gimple_opt_pass pass_del_ssa = -{ - { - GIMPLE_PASS, - "optimized", /* name */ - NULL, /* gate */ - rewrite_out_of_ssa, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - TV_TREE_SSA_TO_NORMAL, /* tv_id */ - PROP_cfg | PROP_ssa, /* properties_required */ - 0, /* properties_provided */ - /* ??? If TER is enabled, we also kill gimple. */ - PROP_ssa, /* properties_destroyed */ - TODO_verify_ssa | TODO_verify_flow - | TODO_verify_stmts, /* todo_flags_start */ - TODO_dump_func - | TODO_ggc_collect - | TODO_remove_unused_locals /* todo_flags_finish */ - } -}; |