X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fgvn_pre.c;h=0dd46f824ee608a3b19b49be36b2e44bd34bd24d;hb=9f6646e4b737e3de981f87f4f7cde177a835e61d;hp=eef9e15f6fa3b5b025b486651f7e07b477cec448;hpb=5e905f32b9a1347c700037f09f3432233c42fd73;p=libfirm diff --git a/ir/opt/gvn_pre.c b/ir/opt/gvn_pre.c index eef9e15f6..0dd46f824 100644 --- a/ir/opt/gvn_pre.c +++ b/ir/opt/gvn_pre.c @@ -1,392 +1,931 @@ /* - * Project: libFIRM - * File name: ir/opt/gvn_pre.c - * Purpose: Global Value Numbering Partial Redundancy Elimination - * (VanDrunen Hosking 2004) - * Author: Michael Beck, Rubino Geiss - * Created: - * CVS-ID: $Id$ - * Copyright: (c) 1998-2006 Universität Karlsruhe - * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE. + * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved. + * + * This file is part of libFirm. + * + * This file may be distributed and/or modified under the terms of the + * GNU General Public License version 2 as published by the Free Software + * Foundation and appearing in the file LICENSE.GPL included in the + * packaging of this file. + * + * Licensees holding valid libFirm Professional Edition licenses may use + * this file in accordance with the libFirm Commercial License. + * Agreement provided with the Software. + * + * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE + * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE. */ -#ifdef HAVE_CONFIG_H -# include "config.h" -#endif - -#include +/** + * @file + * @brief Global Value Numbering Partial Redundancy Elimination + * (VanDrunen Hosking 2004) + * @author Michael Beck + * @brief + */ +#include "config.h" -#include "irgraph_t.h" -#include "irgwalk.h" +#include "iroptimize.h" +#include "irflag.h" #include "irdom.h" #include "irouts.h" -#include "pset.h" #include "irgopt.h" -#include "iropt_t.h" -#include "irprintf.h" -#include "irnode_t.h" +#include "irgwalk.h" #include "ircons.h" #include "irgmod.h" +#include "valueset.h" +#include "irnodehashmap.h" +#include "irnodeset.h" +#include "iredges.h" +#include "iropt_dbg.h" #include "debug.h" -#include "gvn_pre.h" +#include "irpass.h" -/* */ +#include "irgraph_t.h" +#include "irnode_t.h" +#include "iropt_t.h" + +/** Additional info we need for every block. */ typedef struct block_info { - pset *nodes; /**< the set of nodes per block */ - pset *avail_out; /**< the Avail_out set for a block */ - pset *antic_in; /**< the Antic_in set for a block */ - pset *new_set; /**< the set of all new values for a block */ - ir_node *avail; /**< the get_map(avail, block) result */ - int not_found; /**< non-zero, if avail was not found in this block */ - struct block_info *next; + ir_valueset_t *exp_gen; /**< contains this blocks clean expressions */ + ir_valueset_t *avail_out; /**< The Avail_out set for a block. */ + ir_valueset_t *antic_in; /**< The Antic_in set for a block. */ + ir_valueset_t *new_set; /**< The set of all new values for a block. */ + ir_nodehashmap_t *trans; /**< contains translated nodes in block */ + ir_node *avail; /**< The get_map(avail, block) result. */ + ir_node *block; /**< The Block of the block info. */ + struct block_info *next; /**< Links all entries, so we can recover the sets easily. */ + int found; /**< Non-zero, if avail was found in this block. */ } block_info; -typedef struct avail_env { - struct obstack *obst; /**< the obstack to allocate on */ - ir_node *start_block; /**< the start block of the current graph */ - ir_node *end_block; /**< the end block of the current graph */ - block_info *list; /**< links all block info entires for easier recovery */ - int changes; /**< non-zero, if calculation of Antic_in has changed */ -} avail_env; +/** + * A pair of nodes that must be exchanged. + * We must defer the exchange because our hash-sets cannot + * find an already replace node else. + */ +typedef struct elim_pair { + ir_node *old_node; /**< The old node that will be replaced. */ + ir_node *new_node; /**< The new node. */ + struct elim_pair *next; /**< Links all entries in a list. */ + int reason; /**< The reason for the replacement. */ +} elim_pair; + +/** The environment for the GVN-PRE algorithm */ +typedef struct pre_env { + struct obstack *obst; /**< The obstack to allocate on. */ + ir_node *start_block; /**< The start block of the current graph. */ + ir_node *end_block; /**< The end block of the current graph */ + block_info *list; /**< Links all block info entries for easier recovery. */ + elim_pair *pairs; /**< A list of node pairs that must be eliminated. */ + unsigned last_idx; /**< last node index of "old" nodes, all higher indexes are newly created once. */ + char changes; /**< Non-zero, if calculation of Antic_in has changed. */ + char first_iter; /**< non-zero for first iteration */ +} pre_env; /** The debug module handle. */ -static firm_dbg_module_t *dbg; +DEBUG_ONLY(static firm_dbg_module_t *dbg;) + +/* ---------- Functions for Value sets ---------- */ + /** - * returns non-zero if a node is movable. + * computes dst = dst \/ src for value sets + * + * @param dst the union result set + * @param src the source set */ -static int is_nice_value(ir_node *n) { - ir_mode *mode = get_irn_mode(n); - - if (!mode_is_data(mode)) - return 0; - if (is_irn_constlike(n)) - return 0; - return (get_irn_pinned(n) != op_pin_state_pinned); +static void value_union(ir_valueset_t *dst, ir_valueset_t *src) +{ + ir_valueset_iterator_t iter; + ir_node *value, *expr; + + foreach_valueset(src, value, expr, iter) { + /* dominator tree walk; use first available expr as leader */ + ir_valueset_insert(dst, value, expr); + } } -#define pset_foreach(v, s) for ((v) = pset_first(s); (v); (v) = pset_next(s)) -/** computes dst = dst \/ src */ -static void pset_union(pset *dst, pset *src, unsigned (*hash)(void *)) +/* ---------- Functions for Values ---------- */ + +/** + * Remember adds a node e to the GCSE valuetable. + * + * @param e a node representing an expression + * @return the final value for the expression e + */ +static ir_node *remember(ir_node *e) { - void *entry; + ir_node *value; + + if (is_Proj(e)) { + ir_node *pred = get_Proj_pred(e); + ir_node *v_pred = identify_remember(pred); + + if (v_pred != pred) { + ir_node *proj = new_r_Proj(v_pred, get_irn_mode(e), get_Proj_proj(e)); + value = identify_remember(proj); + return value; + } + } - pset_foreach(entry, src) { - pset_insert(dst, entry, ir_node_hash(entry)); - } + value = identify_remember(e); + return value; +} /* identify */ + +/** + * Identify does a lookup in the GCSE valuetable. + * + * @param e a node representing an expression + * @return a node representing the value or NULL if no identified + */ +static ir_node *identify(ir_node *e) +{ + return identify_remember(e); +} + +/** + * Returns the block info of a block. + * + * @param block the block + * @return block info of block + */ +static block_info *get_block_info(ir_node *block) +{ + block_info *info = (block_info*)get_irn_link(block); + return info; } +/** + * Allocate block info for block block. + * + * @param block the block + * @param env the environment + */ +static void alloc_blk_info(ir_node *block, pre_env *env) +{ + block_info *info = OALLOC(env->obst, block_info); + + set_irn_link(block, info); + info->exp_gen = ir_valueset_new(16); + info->avail_out = ir_valueset_new(16); + info->antic_in = ir_valueset_new(16); + /* valueset has much nicer interface */ + info->trans = XMALLOC(ir_nodehashmap_t); + ir_nodehashmap_init(info->trans); + + info->new_set = NULL; + info->avail = NULL; + info->block = block; + info->found = 1; + + info->next = env->list; + env->list = info; +} /* alloc_blk_info */ + +/** + * Returns non-zero if a node is movable and a possible candidate for PRE. + * + * @param n the node + * @return non-zero if value is nice + */ +static int is_nice_value(ir_node *n) +{ + ir_mode *mode; + + if (get_irn_mode(n) == mode_M) + return 0; + + if (is_Phi(n)) + return 1; + + while (is_Proj(n)) + n = get_Proj_pred(n); + + /* we may not move pinned nodes */ + if (get_irn_pinned(n) == op_pin_state_pinned) + return 0; + + mode = get_irn_mode(n); + if (!mode_is_data(mode)) { + /* Div and Mod are only nice if they do not use memory. */ + if (! is_Div(n) && ! is_Mod(n)) + return 0; + if (! is_NoMem(get_memop_mem(n))) + return 0; + } + return 1; +} /* is_nice_value */ + + #ifdef DEBUG_libfirm /** - * Dump the Avail or Antic sets + * Dump a value set. + * + * @param set the set to dump + * @param txt a text to describe the set + * @param block the owner block of the set + */ +static void dump_value_set(ir_valueset_t *set, const char *txt, ir_node *block) +{ + ir_valueset_iterator_t iter; + ir_node *value, *expr; + int i; + + DB((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block)); + i = 0; + foreach_valueset(set, value, expr, iter) { + if ((i & 3) == 3) + DB((dbg, LEVEL_2, "\n")); + if (value != expr) + DB((dbg, LEVEL_2, " %+F(%+F),", expr, value)); + else + DB((dbg, LEVEL_2, " %+F,", expr)); + ++i; + } + DB((dbg, LEVEL_2, "\n}\n")); +} /* dump_value_set */ + +/** + * Dump all exp_gen value sets. + * + * @param list the list of block infos to retrieve the sets from */ -static void dump_set(pset *set, char *txt, ir_node *block) +static void dump_all_expgen_sets(block_info *list) { - ir_node *n; - int i; - - DBG((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block)); - i = 0; - pset_foreach(n, set) { - if ((i & 3) == 3) - DBG((dbg, LEVEL_2, "\n")); - DBG((dbg, LEVEL_2, " %+F,", n)); - ++i; - } - DBG((dbg, LEVEL_2, "\n}\n")); -} /* dump_set */ + block_info *bl_info; + + for (bl_info = list; bl_info != NULL; bl_info = bl_info->next) { + dump_value_set(bl_info->exp_gen, "[Exp_gen]", bl_info->block); + } +} #else -#define dump_set(set, txt, block) +#define dump_value_set(set, txt, block) +#define dump_all_expgen_sets(list, txt) #endif /* DEBUG_libfirm */ +/** + * Gets result of nodes phi translation into block. + * + * @param node the node + * @param block the target block + * + * @return a phi translation of node node into block block or NULL + */ +static ir_node *get_translated(ir_node *node, ir_node *block) +{ + if (is_irn_constlike(node)) { + return node; + + } else { + block_info *bi = get_block_info(block); + ir_node *trans = (ir_node *)ir_nodehashmap_get(bi->trans, node); + return trans; + } +} /** - * Return the block info of a block + * Saves result of phi translation of node into predecessor + * at pos of block succ. + * + * @param node the node + * @param succ the successor of the translation target block + * @param pos the position of the predecessor block + * @param trans the translation result + * */ -static block_info *get_block_info(ir_node *block) { - return get_irn_link(block); +static void set_translated(ir_node *node, ir_node *succ, int pos, ir_node *trans) +{ + ir_node *pred = get_Block_cfgpred_block(succ, pos); + block_info *bi = get_block_info(pred); + + ir_nodehashmap_insert(bi->trans, node, trans); } /** - * computes Avail_out(block): + * Checks if a node node is clean in block block for use in antic_in. * - * Avail_in(block) = Avail_out(dom(block)) - * Avail_out(block) = Avail_in(block) \/ Nodes(block) + * A clean node in block block can be hoisted above block block. + * A node is not clean if its value is killed in block block. + * The node can still be hoisted into block block. * - * Precondition: - * This function must be called in the top-down dominance order: - * Then, it computes Leader(Nodes(block)) instead of Nodes(block) ! + * @param n the phi translated or not translated node + * @param block the block + * @return non-zero value for clean node */ -static void compute_avail_top_down(ir_node *block, void *ctx) +static int is_clean_in_block_antic(ir_node *node, ir_node *block) { - avail_env *env = ctx; - block_info *dom_info; - block_info *info = get_block_info(block); - ir_node *dom_blk; + int i; + + if (get_irn_mode(node) == mode_M) + return 0; + + /* a phi only has predecessors in other blocks */ + if (is_Phi(node)) + return 1; + + /* constants are in start block */ + if (is_irn_constlike(node)) + return 1; + + /* what we really want to check + Only for node is translated case; other are clean anyway */ + if (! is_nice_value(node)) { + return 0; + } + + /* cleanliness depends on nodes predecessors + At least if node is translated. */ + for (i = get_irn_arity(node) - 1; i >= 0; --i) { + ir_node *pred = get_irn_n(node, i); + ir_node *trans, *value; + + if (is_irn_constlike(pred)) + continue; + + /* exp_gen only contains clean nodes */ + if (ir_valueset_lookup(get_block_info(block)->exp_gen, pred)) + continue; + + /* block of pred strictly dominates target block. pred irrelevant. */ + if (block_strictly_dominates(get_nodes_block(pred), block)) + continue; + + /* --- pred neither in block, nor dominating -- */ + + /* This pred is in antic_in and such clean. + Not every clean pred is in antic_in though. + Predecessor might be translated or not */ + value = identify(pred); + if (ir_valueset_lookup(get_block_info(block)->antic_in, value)) + continue; + + /* This check is not redundant for translated nodes; + non translated ones are already nice. */ + if (! is_nice_value(pred)) { + DB((dbg, LEVEL_5, "unclean %+F because pred %+F not nice\n", node, pred)); + return 0; + } + + /* predecessor is not translated. This is legal if + predecessor is dominating or in target block (already checked). */ + trans = get_translated(pred, block); + if (trans == NULL) { + DB((dbg, LEVEL_5, "unclean %+F because pred %+F unclean (not translated)\n", node, pred)); + return 0; + + } else { + /* Node and predecessor are translated, but is pred clean? + The value of the translated predecessor has to be in antic_in. */ + ir_node *value = identify(trans); + if (! ir_valueset_lookup(get_block_info(block)->antic_in, value)) { + DB((dbg, LEVEL_5, "unclean %+F because pred %+F value %+F not antic\n", node, pred, value)); + return 0; + } + } + + assert(0 && "should have been catched"); + } + + /* clean */ + return 1; +} /* is_clean_in_block */ - /* we don't need the end block Avail */ - if (block == env->end_block) - return; +/** + * Checks if a node n is clean in block block for exp_gen. + * + * @param n the node + * @param block the block + * @return non-zero value for clean node + */ +static int is_clean_in_block_expgen(ir_node *n, ir_node *block) +{ + int i; - pset_union(info->avail_out, info->nodes, ir_node_hash); + if (get_irn_mode(n) == mode_M) + return 0; - /* the root has no dominator */ - if (block != env->start_block) { - dom_blk = get_Block_idom(block); - assert(is_Block(dom_blk)); + if (is_Phi(n)) + return 1; - dom_info = get_block_info(dom_blk); - assert(dom_info); + if (! is_nice_value(n)) + return 0; - pset_union(info->avail_out, dom_info->avail_out, ir_node_hash); - } - dump_set(info->avail_out, "Avail_out", block); -} + for (i = get_irn_arity(n) - 1; i >= 0; --i) { + ir_node *pred = get_irn_n(n, i); -/* - * Implement phi_translate + /* sufficient for exp_gen because block is always block of node */ + if (get_nodes_block(pred) != block) + continue; + + /* pred is in block, + so it needs to be clean (already in exp_gen) */ + if (! get_irn_link(pred)) { + DB((dbg, LEVEL_5, "unclean %+F because pred %+F unclean\n", n, pred)); + return 0; + } else { + continue; + } + } + return 1; +} /* is_clean_in_block */ + +/** + * Does blocklocal common subexpression elimination (cse). + * + * @param irn the node + * @param ctx the environment */ -static ir_node *phi_translate(ir_node *node, ir_node *block, int pos, avail_env *env) +static void cse_walker(ir_node *irn, void *ctx) { - ir_node *pred_block; - ir_node *res; - int i, arity = get_irn_intra_arity(node); - struct obstack *old; - - if (is_Phi(node)) { - if (get_nodes_block(node) == block) - return get_Phi_pred(node, pos); - return node; - } - - /* check if the node has at least one Phi predecessor */ - for (i = 0; i < arity; ++i) { - ir_node *phi = get_irn_intra_n(node, i); - if (is_Phi(phi) && get_nodes_block(phi) == block) - break; - } - if (i >= arity) { - /* no Phi in the predecessors */ - return node; - } - - pred_block = get_Block_cfgpred_block(block, pos); - - /* Create a copy of the node in the pos'th predecessor block. - Use our environmental obstack, as these nodes are always - temporary. */ - old = current_ir_graph->obst; - current_ir_graph->obst = env->obst; - res = new_ir_node( - get_irn_dbg_info(node), - current_ir_graph, - pred_block, - get_irn_op(node), - get_irn_mode(node), - arity, - get_irn_in(node)); - /* We need the attribute copy here, because the Hash value of a - node might depend on that. */ - copy_node_attr(node, res); - current_ir_graph->obst = old; - - for (i = -1; i < arity; ++i) { - ir_node *pred = get_irn_intra_n(node, i); - - if (! is_Phi(pred)) - set_irn_n(res, i, pred); - else - set_irn_n(res, i, get_Phi_pred(pred, pos)); - } - set_irn_link(res, NULL); - return res; + ir_node *opt = identify_remember(irn); + (void) ctx; + + if (opt != irn) { + DB((dbg, LEVEL_5, "CSE %+F to %+F\n", irn, opt)); + exchange(irn, opt); + } } /** - * computes Antic_in(block): + * Bottom up walker that ensures that every block gets a block info. * + * @param irn the node + * @param ctx the environment */ -static void compute_antic(ir_node *block, void *ctx) +static void block_info_walker(ir_node *irn, void *ctx) { - avail_env *env = ctx; - block_info *succ_info; - block_info *info = get_block_info(block); - ir_node *succ; - int size; - - /* no need for computations in start block */ - if (block == env->start_block) - return; - - size = pset_count(info->antic_in); - - /* the root has no dominator */ - if (block != env->end_block) { - int n_succ = get_Block_n_cfg_outs(block); - - if (n_succ == 1) { - ir_node *node; - int i, pos = -1; - pset *nodes = new_pset(identities_cmp, 8); - - pset_union(nodes, info->nodes, ir_node_hash); - - /* find blocks position in succ's block predecessors */ - succ = get_Block_cfg_out(block, 0); - for (i = get_Block_n_cfgpreds(succ) - 1; i >= 0; --i) { - if (get_Block_cfgpred_block(succ, i) == block) { - pos = i; - break; - } - } - assert(pos >= 0); - - succ_info = get_block_info(succ); - for (node = pset_first(succ_info->antic_in); - node; - node = pset_next(succ_info->antic_in)) { - ir_node *trans = phi_translate(node, succ, pos, env); - - identify_remember(nodes, trans); - - /* add all predecessors of node */ - for (i = get_irn_arity(node) - 1; i >= 0; --i) { - ir_node *pred = get_irn_n(node, i); - ir_node *trans = phi_translate(pred, succ, pos, env); - - if (is_nice_value(trans)) - identify_remember(nodes, trans); - } - } - /* this step calculates Antic_in(b) = Antic_out(b) \/ Nodes(b) */ - pset_union(info->antic_in, nodes, ir_node_hash); - del_pset(nodes); - } - else { - ir_node *n, *succ0; - block_info *succ0_info; - int i; - - assert(n_succ > 1); - - /* Select a successor to compute the disjoint of all Nodes - sets, it might be useful to select the block with the - smallest number of nodes. For simplicity we choose the - first one. */ - succ0 = get_Block_cfg_out(block, 0); - succ0_info = get_block_info(succ0); - for (n = pset_first(succ0_info->antic_in); - n; - n = pset_next(succ0_info->antic_in)) { - /* we need the disjoint */ - for (i = 1; i < n_succ; ++i) { - ir_node *succ = get_Block_cfg_out(block, i); - block_info *succ_info = get_block_info(succ); - if (pset_find(succ_info->antic_in, n, ir_node_hash(n)) == NULL) - break; - } - if (i >= n_succ) { - /* we found a node that is common in all Antic_in(succ(b)), - put it in Antic_in(b) */ - identify_remember(info->antic_in, n); - } - } - /* this step calculates Antic_in(b) = Antic_out(b) \/ Nodes(b) */ - pset_union(info->antic_in, info->nodes, ir_node_hash); - } - } - - if (size != pset_count(info->antic_in)) - /* the Antic_in set has changed */ - env->changes |= 1; - - dump_set(info->antic_in, "Antic_in", block); -} /* compute_antic */ + if (is_Block(irn)) { + pre_env *env = (pre_env*)ctx; + alloc_blk_info(irn, env); + } +} /** - * allocate a block info + * Topological walker puts nodes in top-down topological order into exp_gen set. + * + * @param irn the node + * @param ctx the environment */ -static void alloc_blk_info(ir_node *block, void *ctx) +static void topo_walker(ir_node *irn, void *ctx) { - int i; - avail_env *env = ctx; - block_info *info = obstack_alloc(env->obst, sizeof(block_info)); - - set_irn_link(block, info); - info->nodes = new_pset(identities_cmp, 8); - info->antic_in = new_pset(identities_cmp, 8); - info->avail_out = new_pset(identities_cmp, 8); - info->avail = NULL; - info->not_found = 0; - info->new_set = NULL; - info->next = env->list; - env->list = info->next; - - /* fill the nodes set, we will need it later */ - for (i = get_irn_n_outs(block) - 1; i >= 0; --i) { - ir_node *n = get_irn_out(block, i); - - /* clear the link field here, we need it later */ - set_irn_link(n, NULL); - - /* we cannot optimize pinned nodes, so do not remember them */ - if (is_nice_value(n)) - identify_remember(info->nodes, n); - else if (is_Phi(n) && get_irn_mode(n) != mode_M) { - /* - * Phis are "temporaries" and must be handled special: - * They are avail, but are not in Antic_in - */ - identify_remember(info->avail_out, n); - } - } + ir_node *block; + block_info *info; + ir_node *value; + (void) ctx; + + /* GVN step: remember the value */ + value = remember(irn); + + /* no need to put constants into the sets: they are always redundant */ + if (! is_nice_value(irn) || is_irn_constlike(irn)) + return; + + /* Do not put mode_T nodes info the sets, or PhiT will be created + (which are not allowed in Firm). Instead, put the Proj's here only. */ + if (get_irn_mode(irn) == mode_T) + return; + + block = get_nodes_block(irn); + info = get_block_info(block); + + if (is_clean_in_block_expgen(irn, block)) { + /* two expressions with same value in block; + should have been fixed by cse pass */ + assert(get_nodes_block(irn) == block && + (! ir_valueset_lookup(info->exp_gen, value))); + + DB((dbg, LEVEL_5, "%+F clean in block %+F\n", irn, block)); + + ir_valueset_insert(info->exp_gen, value, irn); + /* flag irn as clean*/ + set_irn_link(irn, irn); + } else { + /* flag irn as not clean */ + set_irn_link(irn, NULL); + } } /** - * Compare two nodes for equal operands. + * Computes Avail_out(block): + * + * Avail_in(block) = Avail_out(dom(block)) + * Avail_out(block) = Avail_in(block) \/ Nodes(block) + * + * Precondition: + * This function must be called in the top-down topological order: + * Then it computes Leader(Nodes(block)) instead of Nodes(block) ! + * + * @param block the block + * @param ctx walker context */ -static int operands_equal(ir_node *n1, ir_node *n2) +static void compute_avail_top_down(ir_node *block, void *ctx) { - int i, arity = get_irn_arity(n1); - assert(n1->op == n2->op && arity == get_irn_arity(n2)); - for (i = 0; i < arity; ++i) - if (get_irn_n(n1, i) != get_irn_n(n2, i)) - return 0; - return 1; + pre_env *env = (pre_env*)ctx; + block_info *dom_info; + block_info *info = get_block_info(block); + ir_node *dom_blk; + + /* filter blocks from topological walker */ + if (! is_Block(block)) + return; + + if (block == env->end_block) + return; + + /* First, add all nodes from the immediate dominator. + This ensures that avail_out contains the leader. + The start block has no dominators. */ + if (block != env->start_block) { + dom_blk = get_Block_idom(block); + assert(is_Block(dom_blk)); + dom_info = get_block_info(dom_blk); + + value_union(info->avail_out, dom_info->avail_out); + } + /* Second, add values from exp_gen. */ + value_union(info->avail_out, info->exp_gen); + + dump_value_set(info->avail_out, "Avail_out", block); } /** - * Get the leader of an expression. In Firm, only - * Phi nodes can be leaders, all other 'leader' are - * handled by the identify_remember mechanism right. + * Translates an expression above a Phi. + * + * @param node the node + * @param block the block the node is translated into + * @param pos the input number of the destination block + * + * @return a node representing the translated value */ -static ir_node *get_leader(ir_node *n) +static ir_node *phi_translate(ir_node *node, ir_node *block, int pos) { - ir_node *l = get_irn_link(n); + ir_node *nn; + ir_node **in; + int i, arity; + + if (is_Phi(node)) { + if (get_nodes_block(node) == block) { + /* a Phi inside target block */ + return get_Phi_pred(node, pos); + } + /* already outside */ + return node; + } + + arity = get_irn_arity(node); + in = XMALLOCN(ir_node *, arity); + + for (i = 0; i < arity; ++i) { + ir_node *pred = get_irn_n(node, i); + ir_node *pred_block = get_Block_cfgpred_block(block,pos); + ir_node *trans = get_translated(pred, pred_block); + + /* if node is topologically first in block then + there is no translated predecessor. + We do not check cleanliness here, so pred might be not clean. */ + if (trans == NULL) + in[i] = pred; + else + in[i] = trans; + } + + nn = new_ir_node( + get_irn_dbg_info(node), + get_irn_irg(node), + get_Block_cfgpred_block(block, pos), + get_irn_op(node), + get_irn_mode(node), + arity, + in); + free(in); + /* We need the attribute copy here, because the Hash value of a + node might depend on that. */ + copy_node_attr(get_irn_irg(node), node, nn); + DB((dbg, LEVEL_5, "New node %+F in %+F origin %+F\n", nn, get_Block_cfgpred_block(block, pos), node)); + + + nn = optimize_node(nn); + DB((dbg, LEVEL_5, "New gcse optimized node %+F origin %+F\n", nn, node)); + + /* During the insert phase we need to compare the global value numbers + of blocks that do not dominate each other. 'Blocksafe' GCSE requires + the two equivalent nodes to be in blocks that dominate each other. + (see identities_cmp() in iropt.c) + If we do not translate a node into the predecessor block, their values + will not be considered equivalent. (we are at a merging block.) + So we have to translate a node into its predecessor block. + If we switched off blocksafety we will find matching values that are + not dominating (in loops) which we cannot use. + + Also, blocksafe GCSE does not kill nn even if its value is already + present in the successor because the predecessor blocks do not dominate. + This is required for antic_in. + + The nodes produced here are not necessarily in the designated block. + They are used to determine the value of node node. + If we use them for hoisting, we need to make sure that they are in the + designated block. fix_translated() does this job. */ + + return nn; +} /* phi_translate */ - if (l) { - assert(is_Phi(l)); - return l; - } - return n; +/** + * Block-walker, computes Antic_in(block). + * + * @param block the block + * @param ctx the walker environment + */ +static void compute_antic(ir_node *block, void *ctx) +{ + pre_env *env = (pre_env*)ctx; + block_info *succ_info; + block_info *info; + ir_node *succ, *value, *expr; + size_t size; + ir_valueset_iterator_t iter; + + /* filter blocks from topologic walker */ + if (! is_Block(block)) + return; + + /* no need for computations in start block */ + if (block == env->start_block) + return; + + /* the end block has no successor */ + if (block == env->end_block) + return; + + info = get_block_info(block); + size = ir_valueset_size(info->antic_in); + int n_succ; + + /* This step puts all generated expression from the + current block into antic_in. + This is needs to be done in the first iteration only. */ + if (env->first_iter) { + foreach_valueset(info->exp_gen, value, expr, iter) { + /* We will have phi nodes in antic in. + This should prevent special cases in several places. */ + ir_valueset_insert(info->antic_in, value, expr); + } + } + + /* TODO handle endless loops. */ + + n_succ = get_Block_n_cfg_outs(block); + if (n_succ == 1) { + int pos = -1; + + /* find blocks position in succ's block predecessors */ + succ = get_Block_cfg_out(block, 0); + pos = get_Block_cfgpred_pos(succ, block); + assert(pos >= 0); + + succ_info = get_block_info(succ); + /* translate into list: we cannot insert into a set we iterate + * and succ might be equal to block for endless loops */ + foreach_valueset(succ_info->antic_in, value, expr, iter) { + ir_node *trans, *newval; + + DB((dbg, LEVEL_5, "Begin phi translate antic: expr %+F from %+F to %d\n", expr, succ, pos)); + + /* TODO if successor block has 1 predecessor we need no phi translation. + But the clean_in_block check is still needed! */ + /* TODO phi translation and clean in block are overlapping, + because phi trans perhaps should know in advance if predecessors are clean. */ + trans = phi_translate(expr, succ, pos); + newval = remember(trans); + + DB((dbg, LEVEL_5, "----> phi translate antic: expr %+F from %+F to %d is trans %+F\n", expr, succ, pos, trans)); + + if (is_clean_in_block_antic(trans, block)) { + if (! is_irn_constlike(trans)) { + ir_valueset_insert(info->antic_in, newval, trans); + } + DB((dbg, LEVEL_5, " translated %+F clean in %+F\n", trans, block)); + + } else { + DB((dbg, LEVEL_5, " translated %+F not clean in %+F\n", trans, block)); + } + + /* We have to set translated anyway + because expr might still be hoisted _into_ block. */ + set_translated(expr, succ, pos, trans); + + DB((dbg, LEVEL_5, "- end: expr %+F -----\n\n", expr)); + } + + } else if (n_succ > 1) { + ir_node *succ0; + block_info *succ0_info; + int i, common = 1; + + /* Select a successor to compute the disjoint of all nodes + sets, it might be useful to select the block with the + smallest number of nodes. For simplicity we choose the + first one. */ + succ0 = get_Block_cfg_out(block, 0); + succ0_info = get_block_info(succ0); + + foreach_valueset(succ0_info->antic_in, value, expr, iter) { + /* we need the disjoint */ + for (i = 1; i < n_succ; ++i) { + ir_node *succ = get_Block_cfg_out(block, i); + block_info *succ_info = get_block_info(succ); + + if (ir_valueset_lookup(succ_info->antic_in, value) == NULL) { + common = 0; + break; + } + } + + if (common) { + /* we found a value that is common in all Antic_in(succ(b)), + put it in Antic_in(b) if the value is not already represented. */ + if (is_clean_in_block_antic(expr, block)) { + ir_valueset_insert(info->antic_in, value, expr); + } + set_translated(expr, succ0, 0, expr); + + } else { + set_translated(expr, succ0, 0, expr); + } + + } + } + + dump_value_set(info->antic_in, "Antic_in", block); + if (size != ir_valueset_size(info->antic_in)) { + env->changes |= 1; + } + +} /* compute_antic */ + +/** + * Finds if the value of expr is a partially redundant value in block. + * + * @param block the block + * @param expr the expression + * + * @return mode of the expression if it is partially redundant else NULL + */ +static ir_mode *find_partially_redundant(ir_node *block, ir_node *expr) +{ + ir_node *first_avail; + int pos, arity = get_irn_arity(block); + int fully_redundant, partially_redundant; + ir_mode *mode; + + DB((dbg, LEVEL_3, "Examine expr %+F of %+F\n", expr, block)); + + partially_redundant = 0; + fully_redundant = 1; + first_avail = NULL; + mode = NULL; + + /* for each predecessor blocks */ + for (pos = 0; pos < arity; ++pos) { + block_info *pred_info; + ir_node *pred_blk = get_Block_cfgpred_block(block, pos); + ir_node *trans_expr, *trans_value, *avail_expr; + + /* ignore bad blocks. */ + if (is_Bad(pred_blk)) + continue; + + trans_expr = get_translated(expr, get_Block_cfgpred_block(block,pos)); + DB((dbg, LEVEL_2, "expr %+F trans @ %d is translated %+F\n", expr, pos, trans_expr)); + /* exp in antic in, so pred is clean + uncover when it is not */ + assert(trans_expr); + + trans_value = identify(trans_expr); + DB((dbg, LEVEL_2, "trans_value %+F\n", trans_value)); + assert(trans_value); + + pred_info = get_block_info(pred_blk); + avail_expr = (ir_node*)ir_valueset_lookup(pred_info->avail_out, trans_value); + DB((dbg, LEVEL_2, "avail_expr %+F\n", avail_expr)); + + if (avail_expr == NULL) { + /* expr not available */ + pred_info->avail = expr; + pred_info->found = 0; + fully_redundant = 0; + + } else { + /* expr is available */ + pred_info->avail = avail_expr; + pred_info->found = 1; + mode = get_irn_mode(avail_expr); + partially_redundant = 1; + + if (first_avail == NULL) + first_avail = avail_expr; + else if (first_avail != avail_expr) + /* Multiple differnet expressions are available */ + fully_redundant = 0; + + DB((dbg, LEVEL_2, "Found %+F from block %+F as %+F in pred %+F\n", expr, block, avail_expr, pred_blk)); + } /* if */ + } /* for */ + + /* If it is not the same value already existing along every predecessor + and it is defined by some predecessor then it is partially redundant. */ + if (! fully_redundant && partially_redundant) + return mode; + else + return NULL; } -static ir_node *has_leader(ir_node *n) +/** + * Copies node and its predecessors to a block that dominates the target block. + * + * @param node the node + * @param target the target block + * + * @return copy of node node dominating target block + */ +static ir_node *fix_translation(ir_node *node, ir_node *target) { - ir_node *l = get_irn_link(n); + ir_node *nn; + int i, arity; + ir_node **ins; - if (l) { - assert(is_Phi(l)); - return l; - } - return NULL; -} + DB((dbg, LEVEL_1, "Fix_translation %+F into %+F\n", node, target)); + + /* identifies unreachable blocks using domination */ + if (get_Block_dom_depth(get_nodes_block(node)) < 0 || + (get_Block_dom_depth(target) < 0)) + return new_r_Bad(get_irn_irg(node), get_irn_mode(node)); + + /* Walk upwards until the node dominates its use in target block. + Precondition is that the node is clean. */ + if (block_dominates(get_nodes_block(node), target)) + return node; + + DB((dbg, LEVEL_1, "Fix_translation%+F of node %+F does not dominate target %+F\n", get_nodes_block(node), node, target)); + + arity = get_irn_arity(node); + ins = XMALLOCN(ir_node*, arity); + + for (i = arity - 1; i >= 0; --i) { + ir_node *pred = get_irn_n(node, i); + ir_node *fixed = fix_translation(pred, target); + + DB((dbg, LEVEL_1, "Fixed %+F to %+F for node %+F\n", pred, fixed, node)); + ins[i] = fixed; + } + + nn = new_ir_node( + get_irn_dbg_info(node), + get_irn_irg(node), + target, + get_irn_op(node), + get_irn_mode(node), + arity, + ins); + free(ins); + copy_node_attr(get_irn_irg(node), node, nn); + + DB((dbg, LEVEL_1, "New fixed node %+F from translated %+F. target %+F\n", nn, node, target)); + + nn = optimize_node(nn); + remember(nn); + return nn; +} /* fix_translation */ + +/** + * Updates the new_set of a block by adding the new_set of + * the immediate dominating block. + * + * @param the block + */ +static void update_new_set(ir_node *block, ir_node *idom) +{ + ir_node *value, *expr; + ir_valueset_iterator_t iter; + block_info *curr_info = get_block_info(block); + block_info *idom_info = get_block_info(idom); + int updated = 0; + + dump_value_set(idom_info->new_set, "[New Set]", idom); + foreach_valueset(idom_info->new_set, value, expr, iter) { + ir_valueset_insert(curr_info->new_set, value, expr); + updated |= ir_valueset_replace(curr_info->avail_out, value, expr); + } + if (updated) { + dump_value_set(curr_info->avail_out, "Updated [Avail_out]", block); + } +} /* update_new_set */ /** * Perform insertion of partially redundant values. - * For every Block node, do the following: + * For every block node, do the following: * 1. Propagate the NEW_SETS of the dominator into the current block. * If the block has multiple predecessors, * 2a. Iterate over the ANTIC expressions for the block to see if @@ -396,243 +935,314 @@ static ir_node *has_leader(ir_node *n) * 2c. Insert a new Phi merging the values of the predecessors. * 2d. Insert the new Phi, and the new expressions, into the * NEW_SETS set. + * + * @param block the block + * @param ctx the walker environment */ static void insert_nodes(ir_node *block, void *ctx) { - avail_env *env = ctx; - ir_node *v, *idom, *first_s; - block_info *curr_info, *idom_info; - int pos, arity = get_irn_intra_arity(block); - int all_same, by_some; - - curr_info = get_block_info(block); - curr_info->new_set = new_pset(identities_cmp, 8); - - if (block == env->start_block) - return; - - idom = get_Block_idom(block); - idom_info = get_block_info(idom); - - /* update the new_sets */ - pset_union(curr_info->new_set, idom_info->new_set, ir_node_hash); - pset_foreach(v, idom_info->new_set) { - ir_node *old = identify_remember(idom_info->new_set, v); - - if (old != v) { - /* v must dominate old here */ - assert(block_dominates(get_nodes_block(v), get_nodes_block(old))); - - pset_remove(curr_info->avail_out, old, ir_node_hash(old)); - identify_remember(curr_info->avail_out, v); - } - } - dump_set(curr_info->avail_out, "[Avail_out]", block); - - if (arity <= 1) - return; - - pset_foreach(v, curr_info->antic_in) { - /* - * If we already have a leader for this node, - * it is totally redundant. - */ - if (has_leader(v)) - continue; - - /* If the value was already computed in the dominator, then - it is totally redundant. Hence we have nothing to insert. */ - if (pset_find(idom_info->avail_out, v, ir_node_hash(v))) { -// DBG((dbg, LEVEL_2, "Found %+F from block %+F avail in dom %+F\n", v, block, idom)); - continue; - } - - all_same = 1; - by_some = 0; - first_s = NULL; - - /* for all predecessor blocks */ - for (pos = 0; pos < arity; ++pos) { - block_info *pred_info; - ir_node *pred_blk = get_Block_cfgpred_block(block, pos); - ir_node *trans, *found; - - /* ignore bad blocks. */ - if (is_Bad(pred_blk)) - continue; - - trans = phi_translate(v, block, pos, env); - - pred_info = get_block_info(pred_blk); - found = pset_find(pred_info->avail_out, trans, ir_node_hash(trans)); - - if (found == NULL) { - all_same = 0; - pred_info->avail = trans; - pred_info->not_found = 1; - } - else { - found = get_leader(found); - pred_info->avail = found; - pred_info->not_found = 0; - by_some = 1; - if (first_s == NULL) - first_s = found; - else if (first_s != found) - all_same = 0; - - DBG((dbg, LEVEL_2, "Found %+F from block %+F as %+F in pred %+F\n", v, block, found, pred_blk)); - } /* if */ - } /* for */ - - /* If it's not the same value already existing along every predecessor, and - it's defined by some predecessor, it is partially redundant. */ - if (! all_same && by_some) { - ir_node *phi, **in; - ir_mode *mode = NULL; - DBG((dbg, LEVEL_1, "Partial redundant %+F from block %+F found\n", v, block)); - - in = xmalloc(arity * sizeof(*in)); - /* for all predecessor blocks */ - for (pos = 0; pos < arity; ++pos) { - ir_node *pred_blk = get_Block_cfgpred_block(block, pos); - block_info *pred_info = get_block_info(pred_blk); - - /* ignore bad blocks. */ - if (is_Bad(pred_blk)) { - in[pos] = new_Bad(); - continue; - } - - /* ignore blocks that already have the expression */ - if (pred_info->not_found) { - ir_node *avail = pred_info->avail; - ir_node *nn; - assert(! is_Phi(avail)); - - mode = get_irn_mode(avail); - nn = new_ir_node( - get_irn_dbg_info(avail), - current_ir_graph, pred_blk, - get_irn_op(avail), - mode, - get_irn_arity(avail), - get_irn_in(avail) + 1); - - pred_info->avail = identify_remember(pred_info->avail_out, nn); - } - in[pos] = pred_info->avail; - } /* for */ - phi = new_r_Phi(current_ir_graph, block, arity, in, mode); - free(in); - identify_remember(curr_info->avail_out, phi); - identify_remember(curr_info->new_set, phi); - /* v might be translated, so add it here */ - identify_remember(curr_info->avail_out, v); - identify_remember(curr_info->new_set, v); - set_irn_link(v, phi); - DBG((dbg, LEVEL_2, "New %+F for redundant %+F created\n", phi, v)); - env->changes |= 1; - } /* if */ - } /* pset_foreach */ + pre_env *env = (pre_env*)ctx; + ir_node *value, *expr, *idom; + block_info *curr_info; + int pos, arity = get_irn_arity(block); + ir_valueset_iterator_t iter; + + /* filter only blocks */ + if (! is_Block(block)) + return; + + /* ensure that even the start block has a new_set */ + curr_info = get_block_info(block); + if (curr_info->new_set) + ir_valueset_del(curr_info->new_set); + curr_info->new_set = ir_valueset_new(16); + + if (block == env->start_block) + return; + + DB((dbg, LEVEL_2, "Insert operation of %+F\n", block)); + + idom = get_Block_idom(block); + update_new_set(block, idom); + + /* process only merge blocks */ + if (arity < 2) + return; + + /* for each antic_in */ + foreach_valueset(curr_info->antic_in, value, expr, iter) { + ir_mode *mode; + ir_node *phi, *phi_value; + ir_node **phi_in; + + /* filter phi nodes from antic in */ + if (is_Phi(expr)) + continue; + + /* A value computed in the dominator is totally redundant. + Hence we have nothing to insert. */ + if (ir_valueset_lookup(get_block_info(idom)->avail_out, value)) { + DB((dbg, LEVEL_2, "Fully redundant expr %+F value %+F\n", expr, value)); + continue; + } + + mode = find_partially_redundant(block, expr); + if (mode == NULL) + continue; + + DB((dbg, LEVEL_1, "Partial redundant %+F from block %+F found\n", expr, block)); + + phi_in = XMALLOCN(ir_node *, arity); + + /* for all predecessor blocks */ + for (pos = 0; pos < arity; ++pos) { + ir_node *pred_blk = get_Block_cfgpred_block(block, pos); + block_info *pred_info; + + /* ignore bad blocks. */ + if (is_Bad(pred_blk)) { + ir_graph *irg = get_irn_irg(pred_blk); + phi_in[pos] = new_r_Bad(irg, mode); + continue; + } + pred_info = get_block_info(pred_blk); + + /* ignore blocks that already have the expression */ + if (! pred_info->found) { + ir_node *translated, *trans_value; + + translated = get_translated(expr, pred_blk); + /* make sure translated domintes its use */ + translated = fix_translation(translated, pred_blk); + DB((dbg, LEVEL_3, "Use translated %+F in %+F because expr %+F not available\n", translated, pred_blk, expr)); + + /* make the new node available */ + trans_value = remember(translated); + ir_valueset_insert(pred_info->avail_out, trans_value, translated); + phi_in[pos] = translated; + DB((dbg, LEVEL_5, "phi_in %+F\n", translated)); + } else { + phi_in[pos] = pred_info->avail; + DB((dbg, LEVEL_5, "phi_in %+F\n", pred_info->avail)); + } + + } /* for */ + + phi = new_r_Phi(block, arity, phi_in, mode); + free(phi_in); + DB((dbg, LEVEL_1, "New %+F for redundant %+F created\n", phi, expr)); + + phi_value = remember(phi); + + /* this 'global' value is now available through the new phi */ + ir_valueset_replace(curr_info->avail_out, value, phi); + /* add this phi and its 'blocklocal' value */ + ir_valueset_insert(curr_info->avail_out, phi_value, phi); + + ir_valueset_insert(curr_info->new_set, value, phi); + ir_valueset_insert(curr_info->new_set, phi_value, phi); + + /* remove from antic_in to prevent reprocessing */ + ir_valueset_remove_iterator(curr_info->antic_in, &iter); + + env->changes |= 1; + + } /* node_set_foreach */ } /* insert_nodes */ /** - * Do the elimination step + * Walker which finds redundant nodes using avail_out sets + * and exchanges them for existing ones. + * We cannot change the graph here as this would affect + * the hash values of the nodes. + * + * @param irn the node + * @param ctx the walker environment */ -static void eliminate_nodes(ir_node *block, void *ctx) +static void eliminate(ir_node *irn, void *ctx) { - avail_env *env = ctx; - block_info *curr_info = get_block_info(block); - ir_node *v; - - pset_foreach(v, curr_info->nodes) { - ir_node *l = identify_remember(curr_info->avail_out, v); - - l = get_leader(l); - if (l != v) { - DBG((dbg, LEVEL_2, "Replacing %+F by %+F\n", v, l)); - exchange(v, l); - } - } -} + pre_env *env = (pre_env*)ctx; + + if (! is_Block(irn)) { + ir_node *block = get_nodes_block(irn); + block_info *bl = get_block_info(block); + ir_node *value = identify(irn); + + if (value != NULL) { + ir_node *expr = (ir_node*)ir_valueset_lookup(bl->avail_out, value); + + if (expr != NULL && expr != irn) { + elim_pair *p = OALLOC(env->obst, elim_pair); + + p->old_node = irn; + p->new_node = expr; + p->next = env->pairs; + if (get_irn_idx(expr) >= env->last_idx) + p->reason = FS_OPT_GVN_PARTLY; + else + p->reason = FS_OPT_GVN_FULLY; + env->pairs = p; + } + } + } +} /* eliminate */ +/** + * Do all the recorded changes and optimize + * newly created Phi's. + * + * @param pairs list of elimination pairs + */ +static void eliminate_nodes(elim_pair *pairs) +{ + elim_pair *p; + + for (p = pairs; p != NULL; p = p->next) { + /* might be already changed */ + p->new_node = skip_Id(p->new_node); + + DB((dbg, LEVEL_1, "Replacing %+F by %+F\n", p->old_node, p->new_node)); + /* PRE tends to create Phi(self, self, ... , x, self, self, ...) + * which we can optimize here */ + if (is_Phi(p->new_node)) { + int i; + ir_node *res = NULL; + + for (i = get_irn_arity(p->new_node) - 1; i >= 0; --i) { + ir_node *pred = get_irn_n(p->new_node, i); + + if (pred != p->old_node) { + if (res) { + res = NULL; + break; + } + res = pred; + } + } + if (res) { + exchange(p->new_node, res); + p->new_node = res; + } + } + DBG_OPT_GVN_PRE(p->old_node, p->new_node, p->reason); + exchange(p->old_node, p->new_node); + } +} /* eliminate_nodes */ + +/** + * Gvn_Pre pass for graph irg. + * + * @param irg the graph + */ void do_gvn_pre(ir_graph *irg) { - struct obstack obst; - avail_env a_env; - optimization_state_t state; - block_info *p; - int iter = 0; - - /* register a debug mask */ - dbg = firm_dbg_register("firm.opt.gvn_pre"); - - obstack_init(&obst); - a_env.obst = &obst; - a_env.list = NULL; - a_env.start_block = get_irg_start_block(irg); - a_env.end_block = get_irg_end_block(irg); - - /* Move Proj's into the same block as their args, - else we would assign the result to wrong blocks */ - normalize_proj_nodes(irg); - - /* critical edges MUST be removed */ - remove_critical_cf_edges(irg); - - /* we need dominator AND post dominator information */ - if (get_irg_dom_state(irg) != dom_consistent) - compute_doms(irg); - if (get_irg_postdom_state(irg) != dom_consistent) - compute_postdoms(irg); - if (get_irg_outs_state(irg) != outs_consistent) - compute_irg_outs(irg); - - /* - * Switch on GCSE. We need it to correctly compute - * the leader of a node by hashing. - */ - save_optimization_state(&state); - set_opt_global_cse(1); - - /* allocate block info for all blocks */ - irg_block_walk_graph(irg, NULL, alloc_blk_info, &a_env); - - /* compute the available value sets for all blocks */ - dom_tree_walk_irg(irg, compute_avail_top_down, NULL, &a_env); - - /* compute the anticipated value sets for all blocks */ - do { - DBG((dbg, LEVEL_1, "Antic_in Iteration %d starts ...\n", ++iter)); - a_env.changes = 0; - irg_block_walk_graph(irg, compute_antic, NULL, &a_env); -// postdom_tree_walk_irg(irg, compute_antic, NULL, &a_env); - DBG((dbg, LEVEL_1, "------------------------\n")); - } while (a_env.changes != 0); - - /* compute redundant expressions */ - iter = 0; - do { - DBG((dbg, LEVEL_1, "Insert Iteration %d starts ...\n", ++iter)); - a_env.changes = 0; - dom_tree_walk_irg(irg, insert_nodes, NULL, &a_env); - DBG((dbg, LEVEL_1, "------------------------\n")); - } while (a_env.changes != 0); - - /* last step: eliminate nodes */ - dom_tree_walk_irg(irg, eliminate_nodes, NULL, &a_env); - - restore_optimization_state(&state); - - /* clean up: delete all sets */ - for (p = a_env.list; p != NULL; p = p->next) { - if (p->antic_in) - del_pset(p->antic_in); - if (p->avail_out) - del_pset(p->avail_out); - if (p->nodes) - del_pset(p->nodes); - } - obstack_free(&obst, NULL); + struct obstack obst; + pre_env a_env; + optimization_state_t state; + block_info *bl_info; + unsigned antic_iter, insert_iter; + + /* register a debug mask */ + FIRM_DBG_REGISTER(dbg, "firm.opt.gvn_pre"); + /* edges will crash if enabled due to our allocate on other obstack trick */ + edges_deactivate(irg); + + /* algorithm preconditions */ + remove_critical_cf_edges(irg); + /* we get all nodes of a block by following outs */ + assure_irg_outs(irg); + /* we need dominator for Antic_out calculation */ + compute_doms(irg); + compute_postdoms(irg); + + save_optimization_state(&state); + + /* CSE pass + * If there are two nodes with the same value in one block, + * the exp_gen valueset can only contain one of them. */ + set_opt_global_cse(0); + new_identities(irg); + irg_walk_graph(irg, NULL, cse_walker, &a_env); + + DB((dbg, LEVEL_1, "Doing GVN-PRE for %+F\n", irg)); + + /* Switch on GCSE. We need it to correctly compute + the value of a node, which is independent from + its block. */ + set_opt_global_cse(1); + new_identities(irg); + + /* setup environment */ + obstack_init(&obst); + a_env.obst = &obst; + a_env.list = NULL; + a_env.start_block = get_irg_start_block(irg); + a_env.end_block = get_irg_end_block(irg); + a_env.pairs = NULL; + + /* allocate block info */ + irg_walk_blkwise_graph(irg, block_info_walker, NULL, &a_env); + + /* generate exp_gen */ + irg_walk_blkwise_dom_top_down(irg, NULL, topo_walker, &a_env); + dump_all_expgen_sets(a_env.list); + + /* compute the avail_out sets for all blocks */ + dom_tree_walk_irg(irg, compute_avail_top_down, NULL, &a_env); + + /* compute the anticipated value sets for all blocks */ + antic_iter = 0; + a_env.first_iter = 1; + + /* antic_in passes */ + do { + DB((dbg, LEVEL_1, "= Antic_in Iteration %d ========================\n", + ++antic_iter)); + a_env.changes = 0; + irg_walk_blkwise_graph(irg, compute_antic, NULL, &a_env); + a_env.first_iter = 0; + DB((dbg, LEVEL_1, "----------------------------------------------\n")); + /* TODO bad endless loop protection */ + } while (a_env.changes != 0 && antic_iter < 40); + + /* compute redundant expressions */ + insert_iter = 0; + a_env.last_idx = get_irg_last_idx(irg); + do { + ++insert_iter; + DB((dbg, LEVEL_1, "= Insert Iteration %d ==========================\n", insert_iter)); + a_env.changes = 0; + /* TODO topologically top down would be better; fewer iterations. */ + dom_tree_walk_irg(irg, insert_nodes, NULL, &a_env); + DB((dbg, LEVEL_1, "----------------------------------------------\n")); + } while (a_env.changes != 0); + + /* last step: eliminate nodes */ + irg_walk_graph(irg, NULL, eliminate, &a_env); + eliminate_nodes(a_env.pairs); + + /* clean up: delete all sets */ + for (bl_info = a_env.list; bl_info != NULL; bl_info = bl_info->next) { + ir_valueset_del(bl_info->exp_gen); + ir_valueset_del(bl_info->avail_out); + ir_valueset_del(bl_info->antic_in); + ir_nodehashmap_destroy(bl_info->trans); + free(bl_info->trans); + if (bl_info->new_set) + ir_valueset_del(bl_info->new_set); + } + + obstack_free(&obst, NULL); + + /* pin the graph again. + This is needed due to the use of set_opt_global_cse(1) */ + set_irg_pinned(irg, op_pin_state_pinned); + restore_optimization_state(&state); + } /* do_gvn_pre */ + +/* Creates an ir_graph pass for do_gvn_pre. */ +ir_graph_pass_t *do_gvn_pre_pass(const char *name) +{ + return def_graph_pass(name ? name : "gvn_pre", do_gvn_pre); +} /* do_gvn_pre_pass */