X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=ir%2Fopt%2Fgvn_pre.c;h=b3e09c691cded2061f61210785e7861b902c2003;hb=74c0b452c2665b803968a21b556ae2be4a270737;hp=27481a9b4a2e8ad5a15d031d762251b134512da8;hpb=67a7863ec96a1999a8030f8dd89672a2033814b1;p=libfirm diff --git a/ir/opt/gvn_pre.c b/ir/opt/gvn_pre.c index 27481a9b4..b3e09c691 100644 --- a/ir/opt/gvn_pre.c +++ b/ir/opt/gvn_pre.c @@ -1,70 +1,273 @@ /* - * 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 + * @version $Id$ + * @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 "irgwalk.h" +#include "ircons.h" +#include "irgmod.h" +#include "valueset.h" +#include "irnodemap.h" +#include "irnodeset.h" +#include "iredges.h" +#include "iropt_dbg.h" +#include "debug.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 */ - struct block_info *next; + ir_valueset_t *exp_gen; /**< The set of expression per block. */ + 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_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 not_found; /**< Non-zero, if avail was not found in this block. */ } block_info; -typedef struct avail_env { - struct obstack *obst; /**< the obstack to allocate on */ - ir_node *start_block; - ir_node *end_block; - block_info *list; /**< links all block info entires for easier recovery */ - int changes; /**< non-zero, if calculation of Antic_in has changed */ -} avail_env; - /** - * returns non-zero if a node is movable. + * A pair of nodes that must be exchanged. + * We must defer the exchange because our hash-sets cannot + * find an already replace node else. */ -static int is_nice_value(ir_node *n) { - ir_mode *mode = get_irn_mode(n); +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; + +static ir_nodemap_t value_map; + +/** The debug module handle. */ +DEBUG_ONLY(static firm_dbg_module_t *dbg;) + +/* ---------- Functions for Value sets ---------- */ + +/** computes dst = dst \/ src for value sets */ +static void value_union(ir_valueset_t *dst, ir_valueset_t *src) +{ + ir_valueset_iterator_t iter; + ir_node *value, *expr; - if (mode == mode_M || mode == mode_X) - return 0; - return (get_irn_pinned(n) != op_pin_state_pinned); + foreach_valueset(src, value, expr, iter) { + ir_valueset_insert(dst, value, expr); + } } -/** computes dst = dst \/ src */ -static void pset_union(pset *dst, pset *src, unsigned (*hash)(void *)) + +/* ---------- Functions for Values ---------- */ + +/** + * Add a node e representing the value v to the set. + * + * @param e a node representing an expression + * @param v a node representing a value + * + * @return the final value for the expression e + */ +static ir_node *add(ir_node *e, ir_node *v) { - void *entry; + if (is_Proj(v)) { + ir_node *pred = get_Proj_pred(v); + ir_node *v_pred = identify_remember(pred); + + if (v_pred != pred) { + /* must create a new value here */ + v = new_r_Proj(v_pred, get_irn_mode(v), get_Proj_proj(v)); + } + } + v = identify_remember(v); + ir_nodemap_insert(&value_map, e, v); + return v; +} /* add */ - for (entry = pset_first(src); entry; entry = pset_next(src)) { - pset_insert(dst, entry, ir_node_hash(entry)); - } -} +/** + * Lookup a value in a value set. + * + * @param e a node representing an expression + * + * @return a node representing the value or NULL if + * the given expression is not available + */ +static ir_node *lookup(ir_node *e) +{ + ir_node *value = ir_nodemap_get(&value_map, e); + if (value != NULL) + return identify_remember(value); + return NULL; +} /* lookup */ + +/** + * Return the block info of a block. + * + * @param block the block + */ +static block_info *get_block_info(ir_node *block) +{ + return get_irn_link(block); +} /* get_block_info */ + +/** + * Allocate a block info for a 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); + info->new_set = NULL; + info->avail = NULL; + info->block = block; + info->next = env->list; + env->list = info; + info->not_found = 0; +} /* alloc_blk_info */ /** - * computes Avail_out(block): + * Returns non-zero if a node is movable and a possible candidate for PRE. + * + * @param n the node + */ +static int is_nice_value(ir_node *n) +{ + ir_mode *mode; + + while (is_Proj(n)) + n = get_Proj_pred(n); + if (get_irn_pinned(n) == op_pin_state_pinned) + return 0; + mode = get_irn_mode(n); + if (!mode_is_data(mode)) { + if (! is_Div(n) && ! is_Mod(n) && ! is_DivMod(n)) + return 0; + if (! is_NoMem(get_fragile_op_mem(n))) + return 0; + } + return 1; +} /* is_nice_value */ + +#ifdef DEBUG_libfirm +/** + * 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, 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 */ + +#else +#define dump_value_set(set, txt, block) +#endif /* DEBUG_libfirm */ + +/** + * Topological walker. Allocates block info for every block and place nodes in topological + * order into the nodes set. + */ +static void topo_walker(ir_node *irn, void *ctx) +{ + pre_env *env = ctx; + ir_node *block; + block_info *info; + ir_node *value; + + if (is_Block(irn)) { + /* the topological walker ensures that blocks are visited before anything else */ + alloc_blk_info(irn, env); + return; + } + /* GVN step: remember the value */ + value = add(irn, 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; + + /* place this node into the set of possible nodes of its block */ + block = get_nodes_block(irn); + info = get_block_info(block); + + ir_valueset_insert(info->exp_gen, value, irn); +} /* topo_walker */ + +/** + * Computes Avail_out(block): * * Avail_in(block) = Avail_out(dom(block)) * Avail_out(block) = Avail_in(block) \/ Nodes(block) @@ -72,387 +275,631 @@ static void pset_union(pset *dst, pset *src, unsigned (*hash)(void *)) * Precondition: * This function must be called in the top-down dominance order: * Then, it computes Leader(Nodes(block)) instead of Nodes(block) ! + * + * @param block the block + * @param ctx walker context */ static void compute_avail_top_down(ir_node *block, void *ctx) { - avail_env *env = ctx; - block_info *dom_info; - block_info *info = get_irn_link(block); - ir_node *dom_blk; - int i; - - /* the root has no dominator */ - if (block != env->start_block) { - dom_blk = get_Block_idom(block); - assert(is_Block(dom_blk)); - - dom_info = get_irn_link(dom_blk); - assert(dom_info); - - pset_union(info->avail_out, dom_info->avail_out, ir_node_hash); - pset_union(info->avail_out, info->nodes, ir_node_hash); - } -#ifdef _DEBUG - { - ir_node *n; - - ir_printf("Avail_out(%+F) = {\n", block); - for (i = 0, n = pset_first(info->avail_out); n; ++i, n = pset_next(info->avail_out)) { - if ((i & 3) == 3) - printf("\n"); - ir_printf(" %+F,", n); - } - printf("\n}\n"); - } -#endif -} + pre_env *env = ctx; + block_info *dom_info; + block_info *info = get_block_info(block); + ir_node *dom_blk; + + /* we don't need the end block Avail */ + if (block == env->end_block) + return; + + /* + * First add all nodes from the dominator. + * This must be done to ensure that Antic_out contains the leader + * for every node. The root has no dominator. + */ + if (block != env->start_block) { + dom_blk = get_Block_idom(block); + assert(is_Block(dom_blk)); + + dom_info = get_block_info(dom_blk); + assert(dom_info); + + value_union(info->avail_out, dom_info->avail_out); + } + value_union(info->avail_out, info->exp_gen); + + dump_value_set(info->avail_out, "Avail_out", block); +} /* compute_avail_top_down */ -/* - * Implement phi_translate +/** + * check if a node n is clean in block block. + * + * @param n the node + * @param block the block + * @param set a value set, containing the already processed predecessors */ -static ir_node *phi_translate(ir_node *node, ir_node *block, int pos, avail_env *env) +static int is_clean_in_block(ir_node *n, ir_node *block, ir_valueset_t *set) { - 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, node); - return res; -} + int i; + + if (is_Phi(n)) + return 1; + + if (! is_nice_value(n)) + return 0; + + for (i = get_irn_arity(n) - 1; i >= 0; --i) { + ir_node *pred = get_irn_n(n, i); + ir_node *value; + + if (get_nodes_block(pred) != block) + continue; + + if (is_Phi(pred)) + continue; + + if (! is_nice_value(pred)) + return 0; + + value = lookup(pred); + if (! value) + return 0; + if (! ir_valueset_lookup(set, value)) + return 0; + } + return 1; +} /* is_clean_in_block */ /** - * Retranslate a Phi-translated node back + * Implements phi_translate. Translate a expression above a Phi. + * + * @param node the node + * @param block the block in which the node is translated + * @param pos the input number of the destination block + * @param translated the valueset containing the other already translated nodes + * + * @return a node representing the translated value */ -static ir_node *phi_retrans(ir_node *n, avail_env *env) +static ir_node *phi_translate(ir_node *node, ir_node *block, int pos, ir_valueset_t *translated) { - if (node_is_in_irgs_storage(current_ir_graph, n)) - return n; - return get_irn_link(n); -} + ir_node *nn; + int i, arity; + + if (is_Phi(node)) { + if (get_nodes_block(node) == block) { + /* a Phi inside our block */ + return get_Phi_pred(node, pos); + } + /* already outside */ + return node; + } + + arity = get_irn_arity(node); + + /* check if the node has at least one Phi predecessor */ + for (i = 0; i < arity; ++i) { + ir_node *pred = get_irn_n(node, i); + ir_node *leader = lookup(pred); + ir_node *trans; + + leader = leader != NULL ? leader : pred; + trans = ir_valueset_lookup(translated, leader); + + if ((trans != NULL && trans != leader) || (is_Phi(leader) && get_nodes_block(leader) == block)) + break; + } + if (i >= arity) { + /* no translation needed */ + return node; + } + + nn = new_ir_node( + get_irn_dbg_info(node), + current_ir_graph, + get_nodes_block(node), + 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(current_ir_graph, node, nn); + + for (i = 0; i < arity; ++i) { + ir_node *pred = get_irn_n(node, i); + ir_node *leader = lookup(pred); + ir_node *trans; + + leader = leader != NULL ? leader : pred; + trans = ir_valueset_lookup(translated, leader); + if (trans == NULL) + trans = leader; + + if (is_Phi(trans) && get_nodes_block(trans) == block) + set_irn_n(nn, i, get_Phi_pred(trans, pos)); + else + set_irn_n(nn, i, trans); + } + nn = optimize_node(nn); + return nn; +} /* phi_translate */ /** - * computes Antic_in(block): + * Block-walker, computes Antic_in(block). * + * @param block the block + * @param ctx the walker environment */ static void compute_antic(ir_node *block, void *ctx) { - avail_env *env = ctx; - block_info *succ_info; - block_info *info = get_irn_link(block); - ir_node *succ; - int i, size; - - 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_irn_link(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_irn_link(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_irn_link(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; - -#ifdef _DEBUG - { - ir_node *n; - - ir_printf("Antic_in(%+F) = {\n", block); - for (i = 0, n = pset_first(info->antic_in); n; ++i, n = pset_next(info->antic_in)) { - ir_node *orig = phi_retrans(n, env); - if ((i & 3) == 3) - printf("\n"); - ir_printf(" %+F%", n); - if (orig != n) - ir_printf("{%+F}", orig); - printf(", "); - } - printf("\n}\n"); - } -#endif -} + pre_env *env = ctx; + block_info *succ_info; + block_info *info = get_block_info(block); + ir_node *succ, *value, *expr; + size_t size; + ir_valueset_iterator_t iter; + + /* no need for computations in start block */ + if (block == env->start_block) + return; + + size = ir_valueset_size(info->antic_in); + + /* the end block has no successor */ + if (block != env->end_block) { + int n_succ; + + /* + * This step puts all generated expression from the current + * current block into Antic_in. + * It is enough to do this in the first iteration only, because + * the set info->exp_gen is not changed anymore. + */ + if (env->first_iter) { + foreach_valueset(info->exp_gen, value, expr, iter) { + ir_valueset_insert(info->antic_in, value, expr); + } + } + + 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 = phi_translate(expr, succ, pos, info->antic_in); + + if (is_clean_in_block(trans, block, info->antic_in)) + ir_valueset_insert(info->antic_in, value, trans); + } + } else { /* n_succ > 1 */ + ir_node *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); + 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) + break; + } + if (i >= n_succ) { + /* 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(expr, block, info->antic_in)) + ir_valueset_insert(info->antic_in, value, expr); + } + } + } + } + + /* we do not need a clean here, because we ensure that only cleaned nodes are in exp_gen + * and all other sets */ + + dump_value_set(info->antic_in, "Antic_in", block); + if (size != ir_valueset_size(info->antic_in)) { + /* the Antic_in set has changed */ + env->changes |= 1; + } +} /* compute_antic */ /** - * allocate a block info + * Perform insertion of partially redundant values. + * 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 + * any of them are partially redundant. + * 2b. If so, insert them into the necessary predecessors to make + * the expression fully redundant. + * 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 alloc_blk_info(ir_node *block, void *ctx) +static void insert_nodes(ir_node *block, 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->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); - - /* 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); - } - } -} + pre_env *env = ctx; + ir_node *value, *expr, *idom, *first_s, *worklist; + block_info *curr_info, *idom_info; + int pos, arity = get_irn_arity(block); + int all_same, by_some, updated; + ir_valueset_iterator_t iter; + + /* 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; + + idom = get_Block_idom(block); + idom_info = get_block_info(idom); + + /* update the new_sets */ + 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); + } + + if (arity <= 1) + return; + + /* convert the set into a list. This allows the removal of + * elements from the set */ + worklist = NULL; + foreach_valueset(curr_info->antic_in, value, expr, iter) { + ir_mode *mode; + + /* If the value was already computed in the dominator, then + it is totally redundant. Hence we have nothing to insert. */ + if (ir_valueset_lookup(idom_info->avail_out, value)) { + // DB((dbg, LEVEL_2, "Found %+F from block %+F avail in dom %+F\n", v, block, idom)); + continue; + } + + by_some = 0; + all_same = 1; + first_s = NULL; + mode = 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 *e_prime, *v_prime, *e_dprime; + + /* ignore bad blocks. */ + if (is_Bad(pred_blk)) + continue; + + e_prime = phi_translate(expr, block, pos, curr_info->avail_out); + v_prime = lookup(e_prime); + if (v_prime == NULL) + v_prime = value; + + pred_info = get_block_info(pred_blk); + e_dprime = ir_valueset_lookup(pred_info->avail_out, v_prime); + + if (e_dprime == NULL) { + pred_info->avail = e_prime; + pred_info->not_found = 1; + all_same = 0; + } else { + pred_info->avail = e_dprime; + pred_info->not_found = 0; + mode = get_irn_mode(e_dprime); + e_dprime = e_dprime; + by_some = 1; + if (first_s == NULL) + first_s = e_dprime; + else if (first_s != e_dprime) + all_same = 0; + + DB((dbg, LEVEL_2, "Found %+F from block %+F as %+F in pred %+F\n", expr, block, e_dprime, 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, *l, **in; + + DB((dbg, LEVEL_1, "Partial redundant %+F from block %+F found\n", expr, block)); + + 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 = 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 *e_prime = pred_info->avail; + ir_node *nn; + if (!is_Phi(e_prime)) { + ir_node *proj_pred = NULL; + if (is_Proj(e_prime)) { + ir_node *pred = get_Proj_pred(e_prime); + mode = get_irn_mode(pred); + nn = new_ir_node( + get_irn_dbg_info(pred), + current_ir_graph, pred_blk, + get_irn_op(pred), + mode, + get_irn_arity(pred), + get_irn_in(pred) + 1); + copy_node_attr(current_ir_graph, pred, nn); + + DB((dbg, LEVEL_1, "New node %+F in block %+F created\n", nn, pred_blk)); + proj_pred = nn; + } + mode = get_irn_mode(e_prime); + nn = new_ir_node( + get_irn_dbg_info(e_prime), + current_ir_graph, pred_blk, + get_irn_op(e_prime), + mode, + get_irn_arity(e_prime), + get_irn_in(e_prime) + 1); + copy_node_attr(current_ir_graph, e_prime, nn); + if (proj_pred != NULL) { + set_Proj_pred(nn, proj_pred); + } + + DB((dbg, LEVEL_1, "New node %+F in block %+F created\n", nn, pred_blk)); + l = lookup(expr); + if (l == NULL) { + l = add(expr, value); + } + ir_valueset_insert(pred_info->avail_out, add(nn, l), nn); + pred_info->avail = nn; + } + } + in[pos] = pred_info->avail; + } /* for */ + phi = new_r_Phi(block, arity, in, mode); + l = lookup(expr); + if (l == NULL) { + l = add(expr, value); + } + value = add(phi, l); + ir_valueset_replace(curr_info->avail_out, value, phi); + ir_valueset_insert(curr_info->new_set, value, phi); + free(in); + DB((dbg, LEVEL_1, "New %+F for redundant %+F created\n", phi, expr)); + ir_valueset_remove_iterator(curr_info->antic_in, &iter); + env->changes |= 1; + } /* if */ + } /* node_set_foreach */ +} /* insert_nodes */ /** - * Insert the nodes. + * Walker, change nodes by its value if different. + * + * We cannot do the changes right here, as this would change + * the hash values of the nodes in the avail_out set! + * + * @param irn the node + * @param ctx the walker environment */ -static void insert_nodes(ir_node *block, void *ctx) +static void eliminate(ir_node *irn, void *ctx) { - avail_env *env = ctx; - ir_node *v, *idom, *first_s; - block_info *info, *idom_info; - int pos, arity = get_irn_intra_arity(block); - int all_same, by_some; - - if (arity <= 1) - return; - - info = get_irn_link(block); - - idom = get_Block_idom(block); - idom_info = get_irn_link(idom); - for (v = pset_first(info->antic_in); - v; - v = pset_next(info->antic_in)) { - /* 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))) { -// ir_printf("Found %+F from block %+F avail in dom %+F\n", v, block, idom); - continue; - } - - all_same = 1; - by_some = 0; - first_s = NULL; - - for (pos = 0; pos < arity; ++pos) { - block_info *pred_info; - ir_node *pred = get_Block_cfgpred_block(block, pos); - ir_node *trans, *found; - - if (is_Bad(pred)) - continue; - - trans = phi_translate(v, block, pos, env); - - pred_info = get_irn_link(pred); - found = pset_find(pred_info->avail_out, trans, ir_node_hash(trans)); - - if (found == NULL) { - all_same = 0; - } - else { - by_some = 1; - if (first_s == NULL) - first_s = found; - else if (first_s != found) - all_same = 0; - - ir_printf("Found %+F from block %+F as %+F in pred %+F\n", v, block, found, pred); - } - } - - if (! all_same && by_some) { - ir_printf("Partial redundant %+F from block %+F found\n", v, block); - } - } -} + pre_env *env = ctx; + + if (!is_Block(irn)) { + ir_node *block = get_nodes_block(irn); + block_info *bl = get_block_info(block); + ir_node *value = lookup(irn); + + if (value != NULL) { + ir_node *expr = 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; + p->reason = get_irn_idx(expr) >= env->last_idx ? FS_OPT_GVN_PARTLY : 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_2, "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 */ + +/* + * Argh: Endless loops cause problems, because the + * insert algorithm did not terminate. We get translated nodes that + * references the origin. These nodes are translated again and again... + * + * The current fix is to use post-dominance. This simple ignores + * endless loops, i.e. we cannot optimize them. + */ void do_gvn_pre(ir_graph *irg) { - struct obstack obst; - avail_env a_env; - optimization_state_t state; - block_info *p; - int iter = 0; - - 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); - - 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); - - 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 { -#ifdef _DEBUG - printf("Antic_in Iteration %d starts ...\n", ++iter); -#endif /* _DEBUG */ - a_env.changes = 0; - irg_block_walk_graph(irg, compute_antic, NULL, &a_env); -// postdom_tree_walk_irg(irg, compute_antic, NULL, &a_env); -#ifdef _DEBUG - printf("------------------------\n"); -#endif /* _DEBUG */ - } while (a_env.changes != 0); - - iter = 0; - do { -#ifdef _DEBUG - printf("Insert Iteration %d starts ...\n", ++iter); -#endif /* _DEBUG */ - a_env.changes = 0; - irg_block_walk_graph(irg, insert_nodes, NULL, &a_env); -// dom_tree_walk_irg(irg, insert_nodes, NULL, &a_env); -#ifdef _DEBUG - printf("------------------------\n"); -#endif /* _DEBUG */ - } while (a_env.changes != 0); - - restore_optimization_state(&state); - - 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); - } - obstack_free(&obst, NULL); -} + struct obstack obst; + pre_env a_env; + optimization_state_t state; + block_info *bl_info; + unsigned antic_iter, insert_iter; + ir_node *value, *expr; + + /* 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); + + new_identities(irg); + ir_nodemap_init(&value_map); + + 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; + + /* critical edges MUST be removed */ + remove_critical_cf_edges(irg); + + /* we need dominator for Antic_out calculation */ + assure_doms(irg); + assure_postdoms(irg); + /* we get all nodes of a block by following outs */ + assure_irg_outs(irg); + + /* + * Switch on GCSE. We need it to correctly compute + * the value of a node, which is independent from + * its block. + */ + save_optimization_state(&state); + set_opt_global_cse(1); + + DB((dbg, LEVEL_1, "Doing GVN-PRE for %+F\n", irg)); + + /* allocate block info for all blocks */ + irg_walk_blkwise_dom_top_down(irg, NULL, topo_walker, &a_env); + + /* clean the exp_gen set. Doing this here saves the cleanup in the iteration. */ + for (bl_info = a_env.list; bl_info != NULL; bl_info = bl_info->next) { + ir_valueset_iterator_t iter; + + foreach_valueset(bl_info->exp_gen, value, expr, iter) { + if (!is_clean_in_block(expr, bl_info->block, bl_info->exp_gen)) + ir_valueset_remove_iterator(bl_info->exp_gen, &iter); + } + } + /* 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 */ + antic_iter = 0; + a_env.first_iter = 1; + + /* we use the visited flag to mark non-clean nodes */ + inc_irg_visited(irg); + do { + DB((dbg, LEVEL_1, "Antic_in Iteration %d starts ...\n", ++antic_iter)); + a_env.changes = 0; + postdom_tree_walk_irg(irg, compute_antic, NULL, &a_env); + a_env.first_iter = 0; + DB((dbg, LEVEL_1, "------------------------\n")); + } while (a_env.changes != 0); + + /* compute redundant expressions */ + insert_iter = 0; + a_env.last_idx = get_irg_last_idx(irg); + do { + DB((dbg, LEVEL_1, "Insert Iteration %d starts ...\n", ++insert_iter)); + a_env.changes = 0; + 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); + if (bl_info->new_set) + ir_valueset_del(bl_info->new_set); + } + ir_nodemap_destroy(&value_map); + 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); + + if (a_env.pairs) { + set_irg_outs_inconsistent(irg); + set_irg_loopinfo_inconsistent(irg); + } +} /* 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 */