/*
- * 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 <assert.h>
+/**
+ * @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 "debug.h"
+#include "ircons.h"
#include "irdom.h"
-#include "irouts.h"
-#include "pset.h"
+#include "iredges.h"
+#include "irflag.h"
+#include "irgmod.h"
#include "irgopt.h"
-#include "iropt_t.h"
-#include "irprintf.h"
+#include "irgwalk.h"
+#include "irnodehashmap.h"
+#include "irnodeset.h"
+#include "iropt_dbg.h"
+#include "iroptimize.h"
+#include "irouts.h"
+#include "irpass.h"
+#include "valueset.h"
+
+#include "irgraph_t.h"
#include "irnode_t.h"
-#include "ircons.h"
-#include "irgmod.h"
-#include "debug.h"
-#include "gvn_pre.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;
+/**
+ * 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;
- ir_node *new_node;
- struct elim_pair *next;
+ 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 */
- pset *trans_set; /**< the set of all translated values */
- 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 */
- elim_pair *pairs; /**< a list of node pairs that must be eliminated */
- int changes; /**< non-zero, if calculation of Antic_in has changed */
+ 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;
- if (is_Proj(n))
- return is_nice_value(get_Proj_pred(n));
- 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;
+ ir_node *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))
-typedef unsigned (*HASH_FUNC)(void *);
+/* ---------- Functions for Values ---------- */
-#ifdef DEBUG_libfirm
/**
- * Dump the Avail or Antic sets
+ * 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 void dump_set(pset *set, char *txt, ir_node *block)
+static ir_node *remember(ir_node *e)
{
- ir_node *n;
- int i;
-
- DB((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block));
- i = 0;
- pset_foreach(n, set) {
- if ((i & 3) == 3)
- DB((dbg, LEVEL_2, "\n"));
- DB((dbg, LEVEL_2, " %+F,", n));
- ++i;
- }
- DB((dbg, LEVEL_2, "\n}\n"));
-} /* dump_set */
+ ir_node *value;
-#else
-#define dump_set(set, txt, block)
-#endif /* DEBUG_libfirm */
+ 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;
+ }
+ }
+ value = identify_remember(e);
+ return value;
+} /* identify */
/**
- * Return the block info of a block
+ * 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 block_info *get_block_info(ir_node *block) {
- return get_irn_link(block);
+static ir_node *identify(ir_node *e)
+{
+ return identify_remember(e);
}
-#define new_value_set() new_pset(identities_cmp, 8)
-#define del_value_set(set) del_pset(set)
-
/**
- * Add a value to a value set
+ * Returns the block info of a block.
+ *
+ * @param block the block
+ * @return block info of block
*/
-static ir_node *value_add(pset *value_set, ir_node *n)
+static block_info *get_block_info(ir_node *block)
{
- return identify_remember(value_set, n);
+ return (block_info*)get_irn_link(block);
}
/**
- * Lookup a value in a value set
+ * Allocate block info for block block.
+ *
+ * @param block the block
+ * @param env the environment
*/
-static ir_node *lookup(pset *value_set, ir_node *n)
+static void alloc_block_info(ir_node *block, pre_env *env)
{
- return pset_find(value_set, n, ir_node_hash(n));
-}
+ 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);
-/** computes dst = dst \/ src for value sets */
-static void value_union(pset *dst, pset *src)
+ info->new_set = NULL;
+ info->avail = NULL;
+ info->block = block;
+ info->found = 1;
+
+ info->next = env->list;
+ env->list = info;
+} /* alloc_block_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)
{
- void *entry;
- pset_foreach(entry, src)
- value_add(dst, entry);
-}
+ ir_mode *mode = get_irn_mode(n);
+
+ if (mode == 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;
+
+ 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
/**
- * computes Avail_out(block):
+ * Dump a value set.
*
- * Avail_in(block) = Avail_out(dom(block))
- * Avail_out(block) = Avail_in(block) \/ Nodes(block)
+ * @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;
+ ir_node *expr;
+ int i = 0;
+
+ DB((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block));
+ 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.
*
- * Precondition:
- * This function must be called in the top-down dominance order:
- * Then, it computes Leader(Nodes(block)) instead of Nodes(block) !
+ * @param list the list of block infos to retrieve the sets from
*/
-static void compute_avail_top_down(ir_node *block, void *ctx)
+static void dump_all_expgen_sets(block_info *list)
{
- 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->nodes);
-
- dump_set(info->avail_out, "Avail_out", block);
+ 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_value_set(set, txt, block)
+#define dump_all_expgen_sets(list)
+#endif /* DEBUG_libfirm */
+
/**
- * Returns the Phi-leader if one exists, else NULL.
+ * 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 *has_Phi_leader(ir_node *n)
+static ir_node *get_translated(ir_node *node, ir_node *block)
{
- ir_node *l = get_irn_link(n);
+ block_info *bi;
+ ir_node *trans;
+
+ if (is_irn_constlike(node))
+ return node;
- if (l) {
- assert(is_Phi(l));
- return l;
- }
- return NULL;
-} /* has_Phi_leader */
+ bi = get_block_info(block);
+ trans = ir_nodehashmap_get(ir_node, bi->trans, node);
+ return trans;
+}
/**
- * Get the leader of an expression.
+ * 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 ir_node *find_leader(pset *value_set, ir_node *n)
+static void set_translated(ir_node *node, ir_node *succ, int pos, ir_node *trans)
{
- ir_node *l = has_Phi_leader(n);
- if (l != NULL)
- return l;
- return lookup(value_set, n);
+ ir_node *pred = get_Block_cfgpred_block(succ, pos);
+ block_info *bi = get_block_info(pred);
+
+ ir_nodehashmap_insert(bi->trans, node, trans);
}
/**
- * Implements phi_translate
+ * Checks if a node node is clean in block block for use in antic_in.
+ *
+ * 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.
+ *
+ * @param n the phi translated or not translated node
+ * @param block the block
+ * @return non-zero value for clean node
*/
-static ir_node *phi_translate(ir_node *node, ir_node *block, int pos, pre_env *env)
+static int is_clean_in_block_antic(ir_node *node, ir_node *block)
{
- ir_node *nn, *res;
- int i, arity;
- struct obstack *old;
- ir_node *pred_block = get_Block_cfgpred_block(block, pos);
- block_info *pred_info = get_block_info(pred_block);
-
- if (is_Phi(node)) {
- if (get_nodes_block(node) == block) {
- ir_node *leader, *pred;
- pred = get_Phi_pred(node, pos);
- leader = find_leader(pred_info->avail_out, pred);
- assert(leader || ! is_nice_value(pred));
- node = leader != NULL ? leader : pred;
- }
- return node;
- }
-
- arity = get_irn_intra_arity(node);
-
- /* check if the node has at least one Phi predecessor */
- for (i = 0; i < arity; ++i) {
- ir_node *pred = get_irn_intra_n(node, i);
- ir_node *local_bl = get_irn_intra_n(pred, -1);
- ir_node *leader = find_leader(get_block_info(local_bl)->avail_out, pred);
-
- assert(leader || ! is_nice_value(pred));
- leader = leader != NULL ? leader : pred;
- if (is_Phi(leader) && get_nodes_block(leader) == block)
- break;
- }
- if (i >= arity) {
- /* no Phi in the predecessors */
- return node;
- }
-
- /* 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;
- nn = 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, nn);
-
- set_irn_n(nn, -1, get_irn_intra_n(node, -1));
- for (i = 0; i < arity; ++i) {
- ir_node *pred = get_irn_intra_n(node, i);
- ir_node *local_bl = get_irn_intra_n(pred, -1);
- ir_node *leader = find_leader(get_block_info(local_bl)->avail_out, pred);
-
- leader = leader != NULL ? leader : pred;
- if (is_Phi(leader) && get_nodes_block(leader) == block)
- set_irn_n(nn, i, get_Phi_pred(leader, pos));
- else
- set_irn_n(nn, i, leader);
- }
- set_irn_link(nn, NULL);
-
- res = value_add(env->trans_set, nn);
- current_ir_graph->obst = old;
-
- if (nn != res)
- obstack_free(env->obst, nn);
- else {
- DB((dbg, LEVEL_2, "Translate %+F into %+F\n", node, res));
- }
- return res;
-} /* phi_translate */
+ 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;
+ ir_node *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 */
/**
- * computes Antic_in(block):
+ * 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 void compute_antic(ir_node *block, void *ctx)
+static int is_clean_in_block_expgen(ir_node *n, ir_node *block)
{
- pre_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_value_set();
-
- value_union(nodes, info->nodes);
-
- /* 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);
-
- value_add(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))
- value_add(nodes, trans);
- }
- }
- /* this step calculates Antic_in(b) = Antic_out(b) \/ Nodes(b) */
- value_union(info->antic_in, nodes);
- del_value_set(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 (lookup(succ_info->antic_in, 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) */
- value_add(info->antic_in, n);
- }
- }
- /* this step calculates Antic_in(b) = Antic_out(b) \/ Nodes(b) */
- value_union(info->antic_in, info->nodes);
- }
- }
-
- 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 */
+ int i;
+
+ if (get_irn_mode(n) == mode_M)
+ return 0;
+
+ 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);
+
+ /* 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 */
/**
- * allocate a block info
+ * Does blocklocal common subexpression elimination (CSE).
+ *
+ * @param irn the node
+ * @param ctx the environment
*/
-static void alloc_blk_info(ir_node *block, void *ctx)
+static void cse_walker(ir_node *irn, void *ctx)
{
- int i;
- pre_env *env = ctx;
- block_info *info = obstack_alloc(env->obst, sizeof(block_info));
-
- set_irn_link(block, info);
- info->nodes = new_value_set();
- info->antic_in = new_value_set();
- info->avail_out = new_value_set();
- 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))
- value_add(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
- */
- value_add(info->avail_out, n);
- }
- }
+ 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);
+ }
}
/**
- * Compare two nodes for equal operands.
+ * Bottom up walker that ensures that every block gets a block info.
+ *
+ * @param irn the node
+ * @param ctx the environment
*/
-static int operands_equal(ir_node *n1, ir_node *n2)
+static void block_info_walker(ir_node *irn, void *ctx)
{
- int i, arity;
+ if (is_Block(irn)) {
+ pre_env *env = (pre_env*)ctx;
+ alloc_block_info(irn, env);
+ }
+}
- if (n1 == n2)
- return 1;
+/**
+ * Topological walker puts nodes in top-down topological order into exp_gen set.
+ *
+ * @param irn the node
+ * @param ctx the environment
+ */
+static void topo_walker(ir_node *irn, void *ctx)
+{
+ 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);
+ }
+}
- arity = get_irn_arity(n1);
- assert(n1->op == n2->op && arity == get_irn_arity(n2));
- for (i = 0; i < arity; ++i)
- if (! operands_equal(get_irn_n(n1, i), get_irn_n(n2, i)))
- return 0;
- return 1;
+/**
+ * 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 void compute_avail_top_down(ir_node *block, void *ctx)
+{
+ pre_env *env = (pre_env*)ctx;
+ block_info *dom_info;
+ block_info *info = get_block_info(block);
+ ir_node *dom_block;
+
+ /* 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 immediate dominator. */
+ if (block != env->start_block) {
+ dom_block = get_Block_idom(block);
+ assert(is_Block(dom_block));
+ dom_info = get_block_info(dom_block);
+
+ 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);
}
/**
- * Replace a value in a set by an node computing the same
- * value in a dominator block.
+ * Translates an expression above a Phi.
*
- * @return non-zero if a replacement took place
+ * @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 int value_replace(pset *set, ir_node *e)
+static ir_node *phi_translate(ir_node *node, ir_node *block, int pos)
{
- ir_node *old = value_add(set, e);
+ ir_node *nn;
+ ir_node **in;
+ int i;
+ int 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 (old != e) {
- /* e must dominate old here */
- assert(block_dominates(get_nodes_block(e), get_nodes_block(old)));
+/**
+ * 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;
+ ir_node *value;
+ ir_node *expr;
+ size_t size;
+ ir_valueset_iterator_t iter;
+
+ /* filter blocks from topological 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);
+
+ /* 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. */
+
+ int 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;
+ ir_node *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;
+ int 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;
+ }
+ }
+
+ /* 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 (common && is_clean_in_block_antic(expr, block)) {
+ ir_valueset_insert(info->antic_in, value, expr);
+ }
+ 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;
+ }
- pset_remove(set, old, ir_node_hash(old));
- value_add(set, e);
- return 1;
- }
- return 0;
+} /* 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 = NULL;
+ int pos;
+ int arity = get_irn_arity(block);
+ int fully_redundant = 1;
+ int partially_redundant = 0;
+ ir_mode *mode = NULL;
+
+ DB((dbg, LEVEL_3, "Examine expr %+F of %+F\n", expr, block));
+
+ /* for each predecessor blocks */
+ for (pos = 0; pos < arity; ++pos) {
+ block_info *pred_info;
+ ir_node *pred_block = get_Block_cfgpred_block(block, pos);
+ ir_node *trans_expr;
+ ir_node *trans_value;
+ ir_node *avail_expr;
+
+ /* ignore bad blocks. */
+ if (is_Bad(pred_block))
+ 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_block);
+ 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 different 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_block));
+ } /* 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;
+
+ return NULL;
}
+/**
+ * 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 *nn;
+ int i;
+ int arity;
+ ir_node **ins;
+
+ 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;
+ ir_node *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
* 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)
{
- pre_env *env = ctx;
- ir_node *e, *idom, *first_s;
- block_info *curr_info, *idom_info;
- int pos, arity = get_irn_intra_arity(block);
- int all_same, by_some, updated;
-
- curr_info = get_block_info(block);
- curr_info->new_set = new_value_set();
-
- if (block == env->start_block)
- return;
-
- idom = get_Block_idom(block);
- idom_info = get_block_info(idom);
-
- /* update the new_sets */
- updated = 0;
- dump_set(idom_info->new_set, "[New Set]", idom);
- pset_foreach(e, idom_info->new_set) {
- value_add(curr_info->new_set, e);
- updated |= value_replace(curr_info->avail_out, e);
- }
- if (updated)
- dump_set(curr_info->avail_out, "Updated [Avail_out]", block);
-
- if (arity <= 1)
- return;
-
- pset_foreach(e, curr_info->antic_in) {
- /*
- * If we already have a leader for this node,
- * it is totally redundant.
- */
- if (has_Phi_leader(e))
- continue;
-
- /* If the value was already computed in the dominator, then
- it is totally redundant. Hence we have nothing to insert. */
- if (lookup(idom_info->avail_out, e)) {
-// 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;
-
- /* 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(e, block, pos, env);
- v_prime = e_prime;
-
- pred_info = get_block_info(pred_blk);
- e_dprime = find_leader(pred_info->avail_out, v_prime);
-
- if (e_dprime == NULL) {
- all_same = 0;
- pred_info->avail = e_prime;
- pred_info->not_found = 1;
- }
- else {
- e_dprime = e_dprime;
- pred_info->avail = e_dprime;
- pred_info->not_found = 0;
- 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", e, 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, **in;
- ir_mode *mode = NULL;
- DB((dbg, LEVEL_1, "Partial redundant %+F from block %+F found\n", e, 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 *e_prime = pred_info->avail;
- ir_node *nn;
- assert(! is_Phi(e_prime));
-
- 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);
-
- DB((dbg, LEVEL_2, "New node %+F in block %+F created\n", nn, pred_blk));
- pred_info->avail = value_add(pred_info->avail_out, nn);
- }
- in[pos] = pred_info->avail;
- } /* for */
- phi = new_r_Phi(current_ir_graph, block, arity, in, mode);
- free(in);
- value_add(curr_info->avail_out, phi);
- value_add(curr_info->new_set, phi);
- /* e might be translated, so add it here */
- value_add(curr_info->avail_out, e);
- value_add(curr_info->new_set, e);
- DB((dbg, LEVEL_2, "New %+F for redundant %+F created\n", phi, e));
- set_irn_link(e, phi);
-
- env->changes |= 1;
- } /* if */
- } /* pset_foreach */
+ pre_env *env = (pre_env*)ctx;
+ ir_node *value;
+ ir_node *expr;
+ ir_node *idom;
+ block_info *curr_info;
+ int pos;
+ int 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;
+ ir_node *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_block = get_Block_cfgpred_block(block, pos);
+ block_info *pred_info;
+
+ /* ignore bad blocks. */
+ if (is_Bad(pred_block)) {
+ ir_graph *irg = get_irn_irg(pred_block);
+ phi_in[pos] = new_r_Bad(irg, mode);
+ continue;
+ }
+ pred_info = get_block_info(pred_block);
+
+ /* ignore blocks that already have the expression */
+ if (! pred_info->found) {
+ ir_node *translated = get_translated(expr, pred_block);
+ ir_node *trans_value;
+
+ /* make sure translated dominates its use */
+ translated = fix_translation(translated, pred_block);
+ DB((dbg, LEVEL_3, "Use translated %+F in %+F because expr %+F not available\n", translated, pred_block, 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: collect all changes
- * We cannot do the changes right here, as this would change
- * the hash values of the nodes in the avail_out set!
+ * 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 collect_elim_pairs(ir_node *block, void *ctx)
+static void eliminate(ir_node *irn, void *ctx)
{
- pre_env *env = ctx;
- block_info *curr_info = get_block_info(block);
- ir_node *v;
-
- dump_set(curr_info->nodes, "Updating nodes", block);
- pset_foreach(v, curr_info->nodes) {
- ir_node *l = find_leader(curr_info->avail_out, v);
-
- assert(l);
- if (l != v) {
- elim_pair *p = obstack_alloc(env->obst, sizeof(*p));
-
- p->old_node = v;
- p->new_node = l;
- p->next = env->pairs;
- env->pairs = p;
- }
- }
-}
+ 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.
+ * 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;
+ 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 */
- for (p = pairs; p != NULL; p = p->next) {
- DB((dbg, LEVEL_2, "Replacing %+F by %+F\n", p->old_node, p->new_node));
- exchange(p->old_node, p->new_node);
- }
+/**
+ * Gvn_Pre pass for graph irg.
+ *
+ * @param irg the graph
+ */
+void do_gvn_pre(ir_graph *irg)
+{
+ struct obstack obst;
+ pre_env a_env;
+ optimization_state_t state;
+ block_info *bl_info;
+ unsigned antic_iter;
+ unsigned insert_iter;
+
+ assure_irg_properties(irg,
+ IR_GRAPH_PROPERTY_CONSISTENT_OUTS
+ | IR_GRAPH_PROPERTY_NO_CRITICAL_EDGES
+ | IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+ | IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE);
+
+ /* 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);
+
+ 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);
+
+ confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_NONE);
}
-void do_gvn_pre(ir_graph *irg)
+/* Creates an ir_graph pass for do_gvn_pre. */
+ir_graph_pass_t *do_gvn_pre_pass(const char *name)
{
- struct obstack obst;
- pre_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");
- firm_dbg_set_mask(dbg, SET_LEVEL_2);
-
- obstack_init(&obst);
- a_env.obst = &obst;
- a_env.trans_set = new_value_set();
- 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;
-
- /* 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 for Antic_out calculation */
- if (get_irg_dom_state(irg) != dom_consistent)
- compute_doms(irg);
- /* we get all nodes of a block by following outs */
- 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);
-
- DB((dbg, LEVEL_1, "Doing GVN-PRE for %e\n", get_irg_entity(irg)));
-
- /* 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 {
- DB((dbg, LEVEL_1, "Antic_in Iteration %d starts ...\n", ++iter));
- a_env.changes = 0;
- irg_block_walk_graph(irg, compute_antic, NULL, &a_env);
- DB((dbg, LEVEL_1, "------------------------\n"));
- } while (a_env.changes != 0);
-
- /* compute redundant expressions */
- iter = 0;
- do {
- DB((dbg, LEVEL_1, "Insert Iteration %d starts ...\n", ++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 */
- dom_tree_walk_irg(irg, collect_elim_pairs, NULL, &a_env);
- eliminate_nodes(a_env.pairs);
-
- restore_optimization_state(&state);
-
- /* clean up: delete all sets */
- for (p = a_env.list; p != NULL; p = p->next) {
- if (p->antic_in)
- del_value_set(p->antic_in);
- if (p->avail_out)
- del_value_set(p->avail_out);
- if (p->nodes)
- del_value_set(p->nodes);
- }
- del_value_set(a_env.trans_set);
- obstack_free(&obst, NULL);
- set_irg_pinned(irg, op_pin_state_pinned);
-
- if (a_env.pairs) {
- set_irg_outs_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
- }
-} /* do_gvn_pre */
+ return def_graph_pass(name ? name : "gvn_pre", do_gvn_pre);
+}
projects / libfirm / blobdiff