/*
- * Project: libFIRM
- * File name: ir/opt/cfopt.c
- * Purpose: Partial condition evaluation
- * Author: Christoph Mallon, Matthias Braun
- * Created: 10. Sep. 2006
- * 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.
+ */
+
+/**
+ * @file
+ * @brief Partial condition evaluation
+ * @date 10. Sep. 2006
+ * @author Christoph Mallon, Matthias Braun
+ * @version $Id$
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
+#include "iroptimize.h"
+
#include <assert.h>
#include "array.h"
-#include "condeval.h"
#include "debug.h"
#include "ircons.h"
#include "irgmod.h"
#include "irgraph.h"
#include "tv.h"
+//#define AVOID_PHIB
+
DEBUG_ONLY(static firm_dbg_module_t *dbg);
/**
set_irn_in(node, n + 1, ins);
}
-/**
- * Remove predecessor j from node, which is either a Block or a Phi
- * returns true if only one predecessor is left
- */
-static int remove_pred(ir_node* node, int j)
-{
- int n;
-
- assert(is_Block(node) || is_Phi(node));
-
- n = get_irn_arity(node);
- if (n == 2) {
- ir_node* pred = get_irn_n(node, 1 - j);
-
- if (is_Block(node)) {
- pred = get_nodes_block(pred);
- edges_reroute(node, pred, current_ir_graph);
- } else {
- exchange(node, pred);
- }
- return 1;
- } else {
- ir_node** ins;
- int i;
-
- NEW_ARR_A(ir_node*, ins, n - 1);
- for (i = 0; i < j; i++)
- ins[i] = get_irn_n(node, i);
- for (i++; i < n; i++)
- ins[i - 1] = get_irn_n(node, i);
-
- set_irn_in(node, n - 1, ins);
- return 0;
- }
-}
-
static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
{
int i;
return value;
}
+ irg = get_irn_irg(block);
+ assert(block != get_irg_start_block(irg));
+
// blocks with only 1 pred need no phi
n_cfgpreds = get_Block_n_cfgpreds(block);
if(n_cfgpreds == 1) {
ir_node *pred_block = get_Block_cfgpred_block(block, 0);
- ir_node *value = search_def_and_create_phis(pred_block, mode);
+ ir_node *value = search_def_and_create_phis(pred_block, mode);
set_irn_link(block, value);
mark_irn_visited(block);
for(i = 0; i < n_cfgpreds; ++i)
in[i] = new_Unknown(mode);
- irg = get_irn_irg(block);
phi = new_r_Phi(irg, block, n_cfgpreds, in, mode);
set_irn_link(block, phi);
mark_irn_visited(block);
const ir_edge_t *next;
ir_node *value;
- assert(n_vals > 0);
+ assert(n_vals == 2);
irg = get_irn_irg(vals[0]);
inc_irg_visited(irg);
// Only fix the users of the first, i.e. the original node
value = vals[0];
- // this can happen when fixing phi preds, we mustn't fix the users
- if(get_nodes_block(value) != blocks[0]) return;
-
foreach_out_edge_safe(value, edge, next) {
ir_node *user = get_edge_src_irn(edge);
int j = get_edge_src_pos(edge);
if(get_irn_op(user) == op_End)
continue;
+ if (user_block == blocks[1])
+ continue;
+
DB((dbg, LEVEL_3, ">>> Fixing user %+F (pred %d == %+F)\n", user, j, get_irn_n(user, j)));
if(is_Phi(user)) {
set_Block_cfgpred(block, pos, new_jmp);
}
-typedef struct _condeval_env_t {
- ir_node *true_block;
- pn_Cmp pnc;
- ir_node *cnst;
- unsigned long visited_nr;
+typedef struct condeval_env_t {
+ ir_node *true_block;
+ pn_Cmp pnc;
+ ir_node *cnst;
+ tarval *tv;
+ unsigned long visited_nr;
- ir_node *cnst_pred; /**< the block before the constant */
- int cnst_pos; /**< the pos to the constant block (needed to kill that edge later) */
+ ir_node *cnst_pred; /**< the block before the constant */
+ int cnst_pos; /**< the pos to the constant block (needed to
+ kill that edge later) */
} condeval_env_t;
-static void copy_and_fix(ir_node *block, ir_node *copy_block, int j, const condeval_env_t *env) {
+static ir_node *copy_and_fix_node(const condeval_env_t *env, ir_node *block,
+ ir_node *copy_block, int j, ir_node *node) {
+ int i, arity;
+ ir_node *copy;
+
+ /* we can evaluate Phis right now, all other nodes get copied */
+ if (is_Phi(node)) {
+ copy = get_Phi_pred(node, j);
+ /* we might have to evaluate a phi-cascades */
+ if(get_irn_visited(copy) >= env->visited_nr) {
+ copy = get_irn_link(copy);
+ }
+ } else {
+ copy = exact_copy(node);
+ set_nodes_block(copy, copy_block);
+
+ assert(get_irn_mode(copy) != mode_X);
+
+ arity = get_irn_arity(copy);
+ for(i = 0; i < arity; ++i) {
+ ir_node *pred = get_irn_n(copy, i);
+ ir_node *new_pred;
+
+ if(get_nodes_block(pred) != block)
+ continue;
+
+ if(get_irn_visited(pred) >= env->visited_nr) {
+ new_pred = get_irn_link(pred);
+ } else {
+ new_pred = copy_and_fix_node(env, block, copy_block, j, pred);
+ }
+ set_irn_n(copy, i, new_pred);
+ }
+ }
+
+ set_irn_link(node, copy);
+ set_irn_visited(node, env->visited_nr);
+
+ return copy;
+}
+
+static void copy_and_fix(const condeval_env_t *env, ir_node *block,
+ ir_node *copy_block, int j) {
const ir_edge_t *edge;
/* Look at all nodes in the cond_block and copy them into pred */
foreach_out_edge(block, edge) {
ir_node *node = get_edge_src_irn(edge);
ir_node *copy;
+ ir_mode *mode;
+
+ if (is_Block(node)) {
+ /* Block->Block edge, should be the MacroBlock edge */
+ assert(get_Block_MacroBlock(node) == block && "Block->Block edge found");
+ continue;
+ }
/* ignore control flow */
- if (get_irn_mode(node) == mode_X)
+ mode = get_irn_mode(node);
+ if (mode == mode_X || is_Cond(node))
continue;
+#ifdef AVOID_PHIB
+ /* we may not copy mode_b nodes, because this could produce phi with
+ * mode_bs which can't be handled in all backends. Instead we duplicate
+ * the node and move it to it's users */
+ if (mode == mode_b) {
+ const ir_edge_t *edge, *next;
+ ir_node *pred;
+ int pn;
- /* we can evaluate Phis right now, all other nodes get copied */
- if (is_Phi(node)) {
- copy = get_Phi_pred(node, j);
- } else {
- copy = exact_copy(node);
- set_nodes_block(copy, copy_block);
+ assert(is_Proj(node));
+
+ pred = get_Proj_pred(node);
+ pn = get_Proj_proj(node);
+
+ foreach_out_edge_safe(node, edge, next) {
+ ir_node *cmp_copy;
+ ir_node *user = get_edge_src_irn(edge);
+ int pos = get_edge_src_pos(edge);
+ ir_node *user_block = get_nodes_block(user);
+
+ if(user_block == block)
+ continue;
+
+ cmp_copy = exact_copy(pred);
+ set_nodes_block(cmp_copy, user_block);
+ copy = new_r_Proj(current_ir_graph, user_block, cmp_copy, mode_b, pn);
+ set_irn_n(user, pos, copy);
+ }
+ continue;
}
+#endif
- set_irn_link(node, copy);
- set_irn_visited(node, env->visited_nr);
+ copy = copy_and_fix_node(env, block, copy_block, j, node);
/* we might hit values in blocks that have already been processed by a
* recursive find_phi_with_const call */
foreach_out_edge(block, edge) {
ir_node *vals[2];
ir_node *blocks[2];
-
ir_node *node = get_edge_src_irn(edge);
+ ir_mode *mode;
- if (get_irn_mode(node) == mode_X)
+ if (is_Block(node)) {
+ /* Block->Block edge, should be the MacroBlock edge */
+ assert(get_Block_MacroBlock(node) == block && "Block->Block edge found");
+ continue;
+ }
+
+ mode = get_irn_mode(node);
+ if (mode == mode_X || is_Cond(node))
+ continue;
+#ifdef AVOID_PHIB
+ if (mode == mode_b)
continue;
+#endif
DB((dbg, LEVEL_2, ">> Fixing users of %+F\n", node));
}
}
+/**
+ * returns wether the cmp evaluates to true or false, or can't be evaluated!
+ * 1: true, 0: false, -1: can't evaluate
+ */
static int eval_cmp(pn_Cmp pnc, tarval *tv1, tarval *tv2) {
pn_Cmp cmp_result = tarval_cmp(tv1, tv2);
// does the compare evaluate to true?
if(cmp_result == pn_Cmp_False)
- return 0;
+ return -1;
if((cmp_result & pnc) != cmp_result)
return 0;
return 1;
}
-static ir_node *find_phi_with_const(ir_node *jump, ir_node *value, condeval_env_t *env) {
+static ir_node *find_const(condeval_env_t *env, ir_node *jump, ir_node *value)
+{
ir_node *block = get_nodes_block(jump);
if(irn_visited(value))
if(is_Const(value)) {
tarval *tv_const = get_Const_tarval(env->cnst);
- tarval *tv = get_Const_tarval(value);
+ tarval *tv = get_Const_tarval(value);
- if(!eval_cmp(env->pnc, tv, tv_const))
+ if(eval_cmp(env->pnc, tv, tv_const) <= 0) {
return NULL;
+ }
DB((
dbg, LEVEL_1,
return block;
}
+ if(is_Phi(value)) {
+ int i, arity;
+
+ /* the phi has to be in the same block as the jump */
+ if(get_nodes_block(value) != block) {
+ return NULL;
+ }
+
+ arity = get_irn_arity(value);
+ for(i = 0; i < arity; ++i) {
+ ir_node *copy_block;
+ ir_node *phi_pred = get_Phi_pred(value, i);
+ ir_node *cfgpred = get_Block_cfgpred(block, i);
+
+ copy_block = find_const(env, cfgpred, phi_pred);
+ if(copy_block == NULL)
+ continue;
+
+ /* copy duplicated nodes in copy_block and fix SSA */
+ copy_and_fix(env, block, copy_block, i);
+
+ if(copy_block == get_nodes_block(cfgpred)) {
+ env->cnst_pred = block;
+ env->cnst_pos = i;
+ }
+
+ /* return now as we can't process more possibilities in 1 run */
+ return copy_block;
+ }
+ }
+
+ return NULL;
+}
+
+static ir_node *find_candidate(condeval_env_t *env, ir_node *jump,
+ ir_node *value)
+{
+ ir_node *block = get_nodes_block(jump);
+
+ if(irn_visited(value)) {
+ return NULL;
+ }
+ mark_irn_visited(value);
+
+ if(is_Const(value)) {
+ tarval *tv = get_Const_tarval(value);
+
+ if(tv != env->tv)
+ return NULL;
+
+ DB((
+ dbg, LEVEL_1,
+ "> Found condition evaluation candidate %+F->%+F\n",
+ env->true_block, block
+ ));
+
+ // adjust true_block to point directly towards our jump
+ add_pred(env->true_block, jump);
+
+ split_critical_edge(env->true_block, 0);
+
+ // we need a bigger visited nr when going back
+ env->visited_nr++;
+
+ return block;
+ }
if(is_Phi(value)) {
int i, arity;
for(i = 0; i < arity; ++i) {
ir_node *copy_block;
ir_node *phi_pred = get_Phi_pred(value, i);
- ir_node *cfgpred = get_Block_cfgpred(block, i);
+ ir_node *cfgpred = get_Block_cfgpred(block, i);
- copy_block = find_phi_with_const(cfgpred, phi_pred, env);
+ copy_block = find_candidate(env, cfgpred, phi_pred);
if(copy_block == NULL)
continue;
/* copy duplicated nodes in copy_block and fix SSA */
- copy_and_fix(block, copy_block, i, env);
+ copy_and_fix(env, block, copy_block, i);
if(copy_block == get_nodes_block(cfgpred)) {
env->cnst_pred = block;
- env->cnst_pos = i;
+ env->cnst_pos = i;
}
// return now as we can't process more possibilities in 1 run
return copy_block;
}
}
+ if(is_Proj(value)) {
+ ir_node *left;
+ ir_node *right;
+ int pnc;
+ ir_node *cmp = get_Proj_pred(value);
+ if(!is_Cmp(cmp))
+ return NULL;
+
+ left = get_Cmp_left(cmp);
+ right = get_Cmp_right(cmp);
+ pnc = get_Proj_proj(value);
+
+ /* we assume that the constant is on the right side, swap left/right
+ * if needed */
+ if(is_Const(left)) {
+ ir_node *t = left;
+ left = right;
+ right = t;
+
+ pnc = get_inversed_pnc(pnc);
+ }
+
+ if(!is_Const(right))
+ return 0;
+
+ if(get_nodes_block(left) != block) {
+ return 0;
+ }
+
+ /* negate condition when we're looking for the false block */
+ if(env->tv == get_tarval_b_false()) {
+ pnc = get_negated_pnc(pnc, get_irn_mode(right));
+ }
+
+ // (recursively) look if a pred of a phi is a constant
+ env->pnc = pnc;
+ env->cnst = right;
+
+ return find_const(env, jump, left);
+ }
return NULL;
}
-
/**
- * Block-walker: searchs for the following construct
+ * Block-walker: searches for the following construct
*
* Const or Phi with constants
* |
{
condeval_env_t env;
int *changed = data;
- ir_graph *irg = current_ir_graph;
- ir_node *copy_block;
- ir_node *pred;
+ ir_node *selector;
ir_node *projx;
ir_node *cond;
- ir_node *cmp;
- ir_node *left;
- ir_node *right;
- ir_node *cond_block;
- pn_Cmp pnc;
+ ir_node *copy_block;
+ int selector_evaluated;
+ const ir_edge_t *edge, *next;
+ ir_node* bad;
+ size_t cnst_pos;
if(get_Block_n_cfgpreds(block) != 1)
return;
if (!is_Cond(cond))
return;
- pred = get_Cond_selector(cond);
- // TODO handle switches
- if (get_irn_mode(pred) != mode_b)
+ selector = get_Cond_selector(cond);
+ // TODO handle switch Conds
+ if (get_irn_mode(selector) != mode_b)
return;
- if (!is_Proj(pred))
- return;
- pnc = get_Proj_proj(pred);
-
- cmp = get_Proj_pred(pred);
- assert(is_Cmp(cmp));
-
- left = get_Cmp_left(cmp);
- right = get_Cmp_right(cmp);
- assert(get_irn_mode(left) == get_irn_mode(right));
- /* we assume that the cond_block is the true case */
- if (get_Proj_proj(projx) == pn_Cond_false) {
- pnc = get_negated_pnc(pnc, get_irn_mode(left));
+ /* handle cases that can be immediately evalutated */
+ selector_evaluated = -1;
+ if(is_Proj(selector)) {
+ ir_node *cmp = get_Proj_pred(selector);
+ if(is_Cmp(cmp)) {
+ ir_node *left = get_Cmp_left(cmp);
+ ir_node *right = get_Cmp_right(cmp);
+ if(is_Const(left) && is_Const(right)) {
+ int pnc = get_Proj_proj(selector);
+ tarval *tv_left = get_Const_tarval(left);
+ tarval *tv_right = get_Const_tarval(right);
+
+ selector_evaluated = eval_cmp(pnc, tv_left, tv_right);
+ if(selector_evaluated < 0)
+ return;
+ }
+ }
+ } else if(is_Const(selector)) {
+ tarval *tv = get_Const_tarval(selector);
+ if(tv == get_tarval_b_true()) {
+ selector_evaluated = 1;
+ } else {
+ assert(tv == get_tarval_b_false());
+ selector_evaluated = 0;
+ }
}
- /* we assume that the constant is on the right side, swap left/right
- * if needed */
- if(is_Const(left)) {
- ir_node *t = left;
- left = right;
- right = t;
-
- pnc = get_inversed_pnc(pnc);
+ env.cnst_pred = NULL;
+ if (get_Proj_proj(projx) == pn_Cond_false) {
+ env.tv = get_tarval_b_false();
+ if(selector_evaluated >= 0)
+ selector_evaluated = !selector_evaluated;
+ } else {
+ env.tv = get_tarval_b_true();
}
- if(!is_Const(right))
+ if(selector_evaluated == 0) {
+ bad = new_Bad();
+ exchange(projx, bad);
+ *changed = 1;
return;
-
- cond_block = get_nodes_block(cond);
-
- // special case: comparing a constant with a constant
- if(is_Const(left)) {
- tarval *tv1 = get_Const_tarval(left);
- tarval *tv2 = get_Const_tarval(right);
- ir_node *pred;
- if(eval_cmp(pnc, tv1, tv2)) {
- pred = new_r_Jmp(irg, cond_block);
- } else {
- pred = new_Bad();
- }
- set_Block_cfgpred(block, 0, pred);
+ } else if(selector_evaluated == 1) {
+ dbg_info *dbgi = get_irn_dbg_info(selector);
+ ir_node *jmp = new_rd_Jmp(dbgi, current_ir_graph, get_nodes_block(projx));
+ exchange(projx, jmp);
*changed = 1;
- set_irg_doms_inconsistent(irg);
- set_irg_extblk_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
- } else {
- if(get_nodes_block(left) != cond_block)
- return;
+ return;
+ }
- // (recursively) look if a pred of a phi is a constant
- env.true_block = block;
- env.pnc = pnc;
- env.cnst = right;
- inc_irg_visited(current_ir_graph);
- env.visited_nr = get_irg_visited(irg);
-
- copy_block = find_phi_with_const(projx, left, &env);
-
- if(copy_block != NULL) {
- /* we have to remove the edge towards the pred as the pred now
- * jumps into the true_block. We also have to shorten phis
- * in our block because of this */
- const ir_edge_t *edge, *next;
+ // (recursively) look if a pred of a phi is a constant
+ env.true_block = block;
+ inc_irg_visited(current_ir_graph);
+ env.visited_nr = get_irg_visited(current_ir_graph);
- /* shorten phis */
- foreach_out_edge_safe(env.cnst_pred, edge, next) {
- ir_node *node = get_edge_src_irn(edge);
+ copy_block = find_candidate(&env, projx, selector);
+ if (copy_block == NULL)
+ return;
- if(is_Phi(node))
- remove_pred(node, env.cnst_pos);
- }
+ /* we have to remove the edge towards the pred as the pred now
+ * jumps into the true_block. We also have to shorten phis
+ * in our block because of this */
+ bad = new_Bad();
+ cnst_pos = env.cnst_pos;
- remove_pred(env.cnst_pred, env.cnst_pos);
+ /* shorten phis */
+ foreach_out_edge_safe(env.cnst_pred, edge, next) {
+ ir_node *node = get_edge_src_irn(edge);
- // the graph is changed now
- *changed = 1;
- set_irg_doms_inconsistent(irg);
- set_irg_extblk_inconsistent(irg);
- set_irg_loopinfo_inconsistent(irg);
- }
+ if(is_Phi(node))
+ set_Phi_pred(node, cnst_pos, bad);
}
+
+ set_Block_cfgpred(env.cnst_pred, cnst_pos, bad);
+
+ /* the graph is changed now */
+ *changed = 1;
}
void opt_cond_eval(ir_graph* irg)
{
- int changed;
+ int changed, rerun;
FIRM_DBG_REGISTER(dbg, "firm.opt.condeval");
DB((dbg, LEVEL_1, "===> Performing condition evaluation on %+F\n", irg));
- edges_assure(irg);
remove_critical_cf_edges(irg);
-
normalize_proj_nodes(irg);
+ edges_assure(irg);
set_using_irn_link(irg);
set_using_visited(irg);
+ changed = 0;
do {
- changed = 0;
- irg_block_walk_graph(irg, cond_eval, NULL, &changed);
- } while(changed);
+ rerun = 0;
+ irg_block_walk_graph(irg, cond_eval, NULL, &rerun);
+ changed |= rerun;
+ } while (rerun);
+
+ if (changed) {
+ /* control flow changed, some blocks may become dead */
+ set_irg_outs_inconsistent(irg);
+ set_irg_doms_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+ set_irg_loopinfo_inconsistent(irg);
+ }
clear_using_visited(irg);
clear_using_irn_link(irg);
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