void optimize_cf(ir_graph *irg);
/**
- * Perform partial conditional evaluation on the given graph.
+ * Perform path-sensitive jump threading on the given graph.
*
* @param irg the graph
*/
-void opt_cond_eval(ir_graph* irg);
+void opt_jumpthreading(ir_graph* irg);
/**
* Try to simplify boolean expression in the given ir graph.
+++ /dev/null
-/*
- * 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 $Id$
- */
-#include "config.h"
-
-#include "iroptimize.h"
-
-#include <assert.h>
-#include "array_t.h"
-#include "debug.h"
-#include "ircons.h"
-#include "irgmod.h"
-#include "irgopt.h"
-#include "irgwalk.h"
-#include "irnode.h"
-#include "irnode_t.h"
-#include "iredges.h"
-#include "iredges_t.h"
-#include "irtools.h"
-#include "irgraph.h"
-#include "tv.h"
-#include "opt_confirms.h"
-#include "iropt_dbg.h"
-
-#undef AVOID_PHIB
-
-DEBUG_ONLY(static firm_dbg_module_t *dbg);
-
-/**
- * Add the new predecessor x to node node, which is either a Block or a Phi
- */
-static void add_pred(ir_node* node, ir_node* x)
-{
- ir_node** ins;
- int n;
- int i;
-
- assert(is_Block(node) || is_Phi(node));
-
- n = get_irn_arity(node);
- NEW_ARR_A(ir_node*, ins, n + 1);
- for (i = 0; i < n; i++)
- ins[i] = get_irn_n(node, i);
- ins[n] = x;
- set_irn_in(node, n + 1, ins);
-}
-
-static ir_node *ssa_second_def;
-static ir_node *ssa_second_def_block;
-
-static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode,
- int first)
-{
- int i;
- int n_cfgpreds;
- ir_graph *irg;
- ir_node *phi;
- ir_node **in;
-
- /* This is needed because we create bads sometimes */
- if (is_Bad(block))
- return new_Bad();
-
- /* the other defs can't be marked for cases where a user of the original
- * value is in the same block as the alternative definition.
- * In this case we mustn't use the alternative definition.
- * So we keep a flag that indicated wether we walked at least 1 block
- * away and may use the alternative definition */
- if (block == ssa_second_def_block && !first) {
- return ssa_second_def;
- }
-
- /* already processed this block? */
- if (irn_visited(block)) {
- ir_node *value = (ir_node*) get_irn_link(block);
- return value;
- }
-
- irg = get_irn_irg(block);
- assert(block != get_irg_start_block(irg));
-
- /* a Block with only 1 predecessor needs 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, 0);
-
- set_irn_link(block, value);
- mark_irn_visited(block);
- return value;
- }
-
- /* create a new Phi */
- NEW_ARR_A(ir_node*, in, n_cfgpreds);
- for(i = 0; i < n_cfgpreds; ++i)
- in[i] = new_Unknown(mode);
-
- phi = new_r_Phi(block, n_cfgpreds, in, mode);
- set_irn_link(block, phi);
- mark_irn_visited(block);
-
- /* set Phi predecessors */
- for(i = 0; i < n_cfgpreds; ++i) {
- ir_node *pred_block = get_Block_cfgpred_block(block, i);
- ir_node *pred_val = search_def_and_create_phis(pred_block, mode, 0);
-
- set_irn_n(phi, i, pred_val);
- }
-
- return phi;
-}
-
-/**
- * Given a set of values this function constructs SSA-form for the users of the
- * first value (the users are determined through the out-edges of the value).
- * Uses the irn_visited flags. Works without using the dominance tree.
- */
-static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
- ir_node *second_block, ir_node *second_val)
-{
- ir_graph *irg;
- ir_mode *mode;
- const ir_edge_t *edge;
- const ir_edge_t *next;
-
- /* no need to do anything */
- if (orig_val == second_val)
- return;
-
- irg = get_irn_irg(orig_val);
- inc_irg_visited(irg);
-
- mode = get_irn_mode(orig_val);
- set_irn_link(orig_block, orig_val);
- mark_irn_visited(orig_block);
-
- ssa_second_def_block = second_block;
- ssa_second_def = second_val;
-
- /* Only fix the users of the first, i.e. the original node */
- foreach_out_edge_safe(orig_val, edge, next) {
- ir_node *user = get_edge_src_irn(edge);
- int j = get_edge_src_pos(edge);
- ir_node *user_block = get_nodes_block(user);
- ir_node *newval;
-
- /* ignore keeps */
- if (is_End(user))
- continue;
-
- DB((dbg, LEVEL_3, ">>> Fixing user %+F (pred %d == %+F)\n", user, j, get_irn_n(user, j)));
-
- if (is_Phi(user)) {
- ir_node *pred_block = get_Block_cfgpred_block(user_block, j);
- newval = search_def_and_create_phis(pred_block, mode, 1);
- } else {
- newval = search_def_and_create_phis(user_block, mode, 1);
- }
-
- /* don't fix newly created Phis from the SSA construction */
- if (newval != user) {
- DB((dbg, LEVEL_4, ">>>> Setting input %d of %+F to %+F\n", j, user, newval));
- set_irn_n(user, j, newval);
- }
- }
-}
-
-static void split_critical_edge(ir_node *block, int pos) {
- ir_graph *irg = get_irn_irg(block);
- ir_node *in[1];
- ir_node *new_block;
- ir_node *new_jmp;
-
- in[0] = get_Block_cfgpred(block, pos);
- new_block = new_r_Block(irg, 1, in);
- new_jmp = new_r_Jmp(new_block);
- set_Block_cfgpred(block, pos, new_jmp);
-}
-
-typedef struct condeval_env_t {
- ir_node *true_block;
- ir_node *cmp; /**< The Compare node that might be partial evaluated */
- pn_Cmp pnc; /**< The Compare mode of the Compare node. */
- ir_node *cnst;
- tarval *tv;
- ir_visited_t 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) */
-} condeval_env_t;
-
-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-cascade */
- 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);
- }
- DB((dbg, LEVEL_2, ">> Set Pred of %+F to %+F\n", copy, new_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 */
- 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 its users */
- if (mode == mode_b) {
- const ir_edge_t *edge, *next;
- ir_node *pred;
- int pn;
-
- 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
-
- 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 */
- assert(get_irn_visited(copy) <= env->visited_nr);
- if (get_irn_visited(copy) >= env->visited_nr) {
- ir_node *prev_copy = get_irn_link(copy);
- if (prev_copy != NULL)
- set_irn_link(node, prev_copy);
- }
- }
-
- /* fix data-flow (and reconstruct SSA if needed) */
- foreach_out_edge(block, edge) {
- ir_node *node = get_edge_src_irn(edge);
- ir_node *copy_node;
- 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;
- }
-
- 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));
-
- copy_node = get_irn_link(node);
- construct_ssa(block, node, copy_block, copy_node);
- }
-}
-
-/**
- * returns whether the cmp evaluates to true or false, or can't be evaluated!
- * 1: true, 0: false, -1: can't evaluate
- *
- * @param pnc the compare mode of the Compare
- * @param tv_left the left tarval
- * @param tv_right the right tarval
- */
-static int eval_cmp_tv(pn_Cmp pnc, tarval *tv_left, tarval *tv_right) {
- pn_Cmp cmp_result = tarval_cmp(tv_left, tv_right);
-
- /* does the compare evaluate to true? */
- if (cmp_result == pn_Cmp_False)
- return -1;
- if ((cmp_result & pnc) != cmp_result)
- return 0;
-
- return 1;
-}
-
-/**
- * returns whether the cmp evaluates to true or false, or can't be evaluated!
- * 1: true, 0: false, -1: can't evaluate
- *
- * @param env the environment
- * @param cand the candidate node, either a Const or a Confirm
- */
-static int eval_cmp(condeval_env_t *env, ir_node *cand) {
- if (is_Const(cand)) {
- tarval *tv_cand = get_Const_tarval(cand);
- tarval *tv_cmp = get_Const_tarval(env->cnst);
-
- return eval_cmp_tv(env->pnc, tv_cand, tv_cmp);
- } else { /* a Confirm */
- tarval *res = computed_value_Cmp_Confirm(env->cmp, cand, env->cnst, env->pnc);
-
- if (res == tarval_bad)
- return -1;
- return res == tarval_b_true;
- }
-}
-
-/**
- * Check for Const or Confirm with Const.
- */
-static int is_Const_or_Confirm(const ir_node *node) {
- if (is_Confirm(node))
- node = get_Confirm_bound(node);
- return is_Const(node);
-}
-
-/**
- * get the tarval of a Const or Confirm with
- */
-static tarval *get_Const_or_Confirm_tarval(const ir_node *node) {
- if (is_Confirm(node)) {
- if (get_Confirm_bound(node))
- node = get_Confirm_bound(node);
- }
- return get_Const_tarval(node);
-}
-
-static ir_node *find_const_or_confirm(condeval_env_t *env, ir_node *jump, ir_node *value)
-{
- ir_node *block = get_nodes_block(jump);
-
- if (irn_visited_else_mark(value))
- return NULL;
-
- if (is_Const_or_Confirm(value)) {
- if (eval_cmp(env, value) <= 0) {
- 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;
-
- /* the Phi has to be in the same Block as the Jmp */
- 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_or_confirm(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_else_mark(value)) {
- return NULL;
- }
-
- if (is_Const_or_Confirm(value)) {
- tarval *tv = get_Const_or_Confirm_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;
-
- /* the Phi has to be in the same Block as the Jmp */
- 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_candidate(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;
- }
- }
- 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 == tarval_b_false) {
- pnc = get_negated_pnc(pnc, get_irn_mode(right));
- }
-
- /* (recursively) look if a pred of a Phi is a constant or a Confirm */
- env->cmp = cmp;
- env->pnc = pnc;
- env->cnst = right;
-
- return find_const_or_confirm(env, jump, left);
- }
-
- return NULL;
-}
-
-/**
- * Block-walker: searches for the following construct
- *
- * Const or Phi with constants
- * |
- * Cmp
- * |
- * Cond
- * /
- * ProjX
- * /
- * Block
- */
-static void cond_eval(ir_node* block, void* data)
-{
- condeval_env_t env;
- int *changed = data;
- ir_node *selector;
- ir_node *projx;
- ir_node *cond;
- 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;
-
- projx = get_Block_cfgpred(block, 0);
- if (!is_Proj(projx))
- return;
- assert(get_irn_mode(projx) == mode_X);
-
- cond = get_Proj_pred(projx);
- if (!is_Cond(cond))
- return;
-
- selector = get_Cond_selector(cond);
- /* TODO handle switch Conds */
- if (get_irn_mode(selector) != mode_b)
- return;
-
- /* handle cases that can be immediately evaluated */
- 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_tv(pnc, tv_left, tv_right);
- if (selector_evaluated < 0)
- return;
- }
- }
- } else if (is_Const_or_Confirm(selector)) {
- tarval *tv = get_Const_or_Confirm_tarval(selector);
- if (tv == tarval_b_true) {
- selector_evaluated = 1;
- } else {
- assert(tv == tarval_b_false);
- selector_evaluated = 0;
- }
- }
-
- env.cnst_pred = NULL;
- if (get_Proj_proj(projx) == pn_Cond_false) {
- env.tv = tarval_b_false;
- if (selector_evaluated >= 0)
- selector_evaluated = !selector_evaluated;
- } else {
- env.tv = tarval_b_true;
- }
-
- if (selector_evaluated == 0) {
- bad = new_Bad();
- exchange(projx, bad);
- *changed = 1;
- return;
- } else if (selector_evaluated == 1) {
- dbg_info *dbgi = get_irn_dbg_info(selector);
- ir_node *jmp = new_rd_Jmp(dbgi, get_nodes_block(projx));
- DBG_OPT_COND_EVAL(projx, jmp);
- exchange(projx, jmp);
- *changed = 1;
- return;
- }
-
- /* (recursively) look if a pred of a Phi is a constant or a Confirm */
- env.true_block = block;
- inc_irg_visited(current_ir_graph);
- env.visited_nr = get_irg_visited(current_ir_graph);
-
- copy_block = find_candidate(&env, projx, selector);
- if (copy_block == NULL)
- return;
-
- /* 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;
-
- /* shorten Phis */
- foreach_out_edge_safe(env.cnst_pred, edge, next) {
- ir_node *node = get_edge_src_irn(edge);
-
- 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, rerun;
-
- FIRM_DBG_REGISTER(dbg, "firm.opt.condeval");
-
- DB((dbg, LEVEL_1, "===> Performing condition evaluation on %+F\n", irg));
-
- remove_critical_cf_edges(irg);
- normalize_proj_nodes(irg);
-
- edges_assure(irg);
- ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
-
- changed = 0;
- do {
- rerun = 0;
- irg_block_walk_graph(irg, cond_eval, NULL, &rerun);
- changed |= rerun;
- } while (rerun);
-
- ir_free_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
-
- 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);
- set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
-
- /* Dead code might be created. Optimize it away as it is dangerous
- * to call optimize_df() an dead code. */
- optimize_cf(irg);
- }
-}
--- /dev/null
+/*
+ * 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 Path-Sensitive Jump Threading
+ * @date 10. Sep. 2006
+ * @author Christoph Mallon, Matthias Braun
+ * @version $Id$
+ */
+#include "config.h"
+
+#include "iroptimize.h"
+
+#include <assert.h>
+#include "array_t.h"
+#include "debug.h"
+#include "ircons.h"
+#include "irgmod.h"
+#include "irgopt.h"
+#include "irgwalk.h"
+#include "irnode.h"
+#include "irnode_t.h"
+#include "iredges.h"
+#include "iredges_t.h"
+#include "irtools.h"
+#include "irgraph.h"
+#include "tv.h"
+#include "opt_confirms.h"
+#include "iropt_dbg.h"
+
+#undef AVOID_PHIB
+
+DEBUG_ONLY(static firm_dbg_module_t *dbg);
+
+/**
+ * Add the new predecessor x to node node, which is either a Block or a Phi
+ */
+static void add_pred(ir_node* node, ir_node* x)
+{
+ ir_node** ins;
+ int n;
+ int i;
+
+ assert(is_Block(node) || is_Phi(node));
+
+ n = get_irn_arity(node);
+ NEW_ARR_A(ir_node*, ins, n + 1);
+ for (i = 0; i < n; i++)
+ ins[i] = get_irn_n(node, i);
+ ins[n] = x;
+ set_irn_in(node, n + 1, ins);
+}
+
+static ir_node *ssa_second_def;
+static ir_node *ssa_second_def_block;
+
+static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode,
+ int first)
+{
+ int i;
+ int n_cfgpreds;
+ ir_graph *irg;
+ ir_node *phi;
+ ir_node **in;
+
+ /* This is needed because we create bads sometimes */
+ if (is_Bad(block))
+ return new_Bad();
+
+ /* the other defs can't be marked for cases where a user of the original
+ * value is in the same block as the alternative definition.
+ * In this case we mustn't use the alternative definition.
+ * So we keep a flag that indicated wether we walked at least 1 block
+ * away and may use the alternative definition */
+ if (block == ssa_second_def_block && !first) {
+ return ssa_second_def;
+ }
+
+ /* already processed this block? */
+ if (irn_visited(block)) {
+ ir_node *value = (ir_node*) get_irn_link(block);
+ return value;
+ }
+
+ irg = get_irn_irg(block);
+ assert(block != get_irg_start_block(irg));
+
+ /* a Block with only 1 predecessor needs 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, 0);
+
+ set_irn_link(block, value);
+ mark_irn_visited(block);
+ return value;
+ }
+
+ /* create a new Phi */
+ NEW_ARR_A(ir_node*, in, n_cfgpreds);
+ for(i = 0; i < n_cfgpreds; ++i)
+ in[i] = new_Unknown(mode);
+
+ phi = new_r_Phi(block, n_cfgpreds, in, mode);
+ set_irn_link(block, phi);
+ mark_irn_visited(block);
+
+ /* set Phi predecessors */
+ for(i = 0; i < n_cfgpreds; ++i) {
+ ir_node *pred_block = get_Block_cfgpred_block(block, i);
+ ir_node *pred_val = search_def_and_create_phis(pred_block, mode, 0);
+
+ set_irn_n(phi, i, pred_val);
+ }
+
+ return phi;
+}
+
+/**
+ * Given a set of values this function constructs SSA-form for the users of the
+ * first value (the users are determined through the out-edges of the value).
+ * Uses the irn_visited flags. Works without using the dominance tree.
+ */
+static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
+ ir_node *second_block, ir_node *second_val)
+{
+ ir_graph *irg;
+ ir_mode *mode;
+ const ir_edge_t *edge;
+ const ir_edge_t *next;
+
+ /* no need to do anything */
+ if (orig_val == second_val)
+ return;
+
+ irg = get_irn_irg(orig_val);
+ inc_irg_visited(irg);
+
+ mode = get_irn_mode(orig_val);
+ set_irn_link(orig_block, orig_val);
+ mark_irn_visited(orig_block);
+
+ ssa_second_def_block = second_block;
+ ssa_second_def = second_val;
+
+ /* Only fix the users of the first, i.e. the original node */
+ foreach_out_edge_safe(orig_val, edge, next) {
+ ir_node *user = get_edge_src_irn(edge);
+ int j = get_edge_src_pos(edge);
+ ir_node *user_block = get_nodes_block(user);
+ ir_node *newval;
+
+ /* ignore keeps */
+ if (is_End(user))
+ continue;
+
+ DB((dbg, LEVEL_3, ">>> Fixing user %+F (pred %d == %+F)\n", user, j, get_irn_n(user, j)));
+
+ if (is_Phi(user)) {
+ ir_node *pred_block = get_Block_cfgpred_block(user_block, j);
+ newval = search_def_and_create_phis(pred_block, mode, 1);
+ } else {
+ newval = search_def_and_create_phis(user_block, mode, 1);
+ }
+
+ /* don't fix newly created Phis from the SSA construction */
+ if (newval != user) {
+ DB((dbg, LEVEL_4, ">>>> Setting input %d of %+F to %+F\n", j, user, newval));
+ set_irn_n(user, j, newval);
+ }
+ }
+}
+
+static void split_critical_edge(ir_node *block, int pos) {
+ ir_graph *irg = get_irn_irg(block);
+ ir_node *in[1];
+ ir_node *new_block;
+ ir_node *new_jmp;
+
+ in[0] = get_Block_cfgpred(block, pos);
+ new_block = new_r_Block(irg, 1, in);
+ new_jmp = new_r_Jmp(new_block);
+ set_Block_cfgpred(block, pos, new_jmp);
+}
+
+typedef struct jumpthreading_env_t {
+ ir_node *true_block;
+ ir_node *cmp; /**< The Compare node that might be partial evaluated */
+ pn_Cmp pnc; /**< The Compare mode of the Compare node. */
+ ir_node *cnst;
+ tarval *tv;
+ ir_visited_t 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) */
+} jumpthreading_env_t;
+
+static ir_node *copy_and_fix_node(const jumpthreading_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-cascade */
+ 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);
+ }
+ DB((dbg, LEVEL_2, ">> Set Pred of %+F to %+F\n", copy, new_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 jumpthreading_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 */
+ 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 its users */
+ if (mode == mode_b) {
+ const ir_edge_t *edge, *next;
+ ir_node *pred;
+ int pn;
+
+ 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
+
+ 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 */
+ assert(get_irn_visited(copy) <= env->visited_nr);
+ if (get_irn_visited(copy) >= env->visited_nr) {
+ ir_node *prev_copy = get_irn_link(copy);
+ if (prev_copy != NULL)
+ set_irn_link(node, prev_copy);
+ }
+ }
+
+ /* fix data-flow (and reconstruct SSA if needed) */
+ foreach_out_edge(block, edge) {
+ ir_node *node = get_edge_src_irn(edge);
+ ir_node *copy_node;
+ 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;
+ }
+
+ 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));
+
+ copy_node = get_irn_link(node);
+ construct_ssa(block, node, copy_block, copy_node);
+ }
+}
+
+/**
+ * returns whether the cmp evaluates to true or false, or can't be evaluated!
+ * 1: true, 0: false, -1: can't evaluate
+ *
+ * @param pnc the compare mode of the Compare
+ * @param tv_left the left tarval
+ * @param tv_right the right tarval
+ */
+static int eval_cmp_tv(pn_Cmp pnc, tarval *tv_left, tarval *tv_right)
+{
+ pn_Cmp cmp_result = tarval_cmp(tv_left, tv_right);
+
+ /* does the compare evaluate to true? */
+ if (cmp_result == pn_Cmp_False)
+ return -1;
+ if ((cmp_result & pnc) != cmp_result)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * returns whether the cmp evaluates to true or false, or can't be evaluated!
+ * 1: true, 0: false, -1: can't evaluate
+ *
+ * @param env the environment
+ * @param cand the candidate node, either a Const or a Confirm
+ */
+static int eval_cmp(jumpthreading_env_t *env, ir_node *cand)
+{
+ if (is_Const(cand)) {
+ tarval *tv_cand = get_Const_tarval(cand);
+ tarval *tv_cmp = get_Const_tarval(env->cnst);
+
+ return eval_cmp_tv(env->pnc, tv_cand, tv_cmp);
+ } else { /* a Confirm */
+ tarval *res = computed_value_Cmp_Confirm(env->cmp, cand, env->cnst, env->pnc);
+
+ if (res == tarval_bad)
+ return -1;
+ return res == tarval_b_true;
+ }
+}
+
+/**
+ * Check for Const or Confirm with Const.
+ */
+static int is_Const_or_Confirm(const ir_node *node)
+{
+ if (is_Confirm(node))
+ node = get_Confirm_bound(node);
+ return is_Const(node);
+}
+
+/**
+ * get the tarval of a Const or Confirm with
+ */
+static tarval *get_Const_or_Confirm_tarval(const ir_node *node)
+{
+ if (is_Confirm(node)) {
+ if (get_Confirm_bound(node))
+ node = get_Confirm_bound(node);
+ }
+ return get_Const_tarval(node);
+}
+
+static ir_node *find_const_or_confirm(jumpthreading_env_t *env, ir_node *jump,
+ ir_node *value)
+{
+ ir_node *block = get_nodes_block(jump);
+
+ if (irn_visited_else_mark(value))
+ return NULL;
+
+ if (is_Const_or_Confirm(value)) {
+ if (eval_cmp(env, value) <= 0) {
+ 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;
+
+ /* the Phi has to be in the same Block as the Jmp */
+ 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_or_confirm(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(jumpthreading_env_t *env, ir_node *jump,
+ ir_node *value)
+{
+ ir_node *block = get_nodes_block(jump);
+
+ if (irn_visited_else_mark(value)) {
+ return NULL;
+ }
+
+ if (is_Const_or_Confirm(value)) {
+ tarval *tv = get_Const_or_Confirm_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;
+
+ /* the Phi has to be in the same Block as the Jmp */
+ 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_candidate(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;
+ }
+ }
+ 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 == tarval_b_false) {
+ pnc = get_negated_pnc(pnc, get_irn_mode(right));
+ }
+
+ /* (recursively) look if a pred of a Phi is a constant or a Confirm */
+ env->cmp = cmp;
+ env->pnc = pnc;
+ env->cnst = right;
+
+ return find_const_or_confirm(env, jump, left);
+ }
+
+ return NULL;
+}
+
+/**
+ * Block-walker: searches for the following construct
+ *
+ * Const or Phi with constants
+ * |
+ * Cmp
+ * |
+ * Cond
+ * /
+ * ProjX
+ * /
+ * Block
+ */
+static void thread_jumps(ir_node* block, void* data)
+{
+ jumpthreading_env_t env;
+ int *changed = data;
+ ir_node *selector;
+ ir_node *projx;
+ ir_node *cond;
+ 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;
+
+ projx = get_Block_cfgpred(block, 0);
+ if (!is_Proj(projx))
+ return;
+ assert(get_irn_mode(projx) == mode_X);
+
+ cond = get_Proj_pred(projx);
+ if (!is_Cond(cond))
+ return;
+
+ selector = get_Cond_selector(cond);
+ /* TODO handle switch Conds */
+ if (get_irn_mode(selector) != mode_b)
+ return;
+
+ /* handle cases that can be immediately evaluated */
+ 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_tv(pnc, tv_left, tv_right);
+ if (selector_evaluated < 0)
+ return;
+ }
+ }
+ } else if (is_Const_or_Confirm(selector)) {
+ tarval *tv = get_Const_or_Confirm_tarval(selector);
+ if (tv == tarval_b_true) {
+ selector_evaluated = 1;
+ } else {
+ assert(tv == tarval_b_false);
+ selector_evaluated = 0;
+ }
+ }
+
+ env.cnst_pred = NULL;
+ if (get_Proj_proj(projx) == pn_Cond_false) {
+ env.tv = tarval_b_false;
+ if (selector_evaluated >= 0)
+ selector_evaluated = !selector_evaluated;
+ } else {
+ env.tv = tarval_b_true;
+ }
+
+ if (selector_evaluated == 0) {
+ bad = new_Bad();
+ exchange(projx, bad);
+ *changed = 1;
+ return;
+ } else if (selector_evaluated == 1) {
+ dbg_info *dbgi = get_irn_dbg_info(selector);
+ ir_node *jmp = new_rd_Jmp(dbgi, get_nodes_block(projx));
+ DBG_OPT_COND_EVAL(projx, jmp);
+ exchange(projx, jmp);
+ *changed = 1;
+ return;
+ }
+
+ /* (recursively) look if a pred of a Phi is a constant or a Confirm */
+ env.true_block = block;
+ inc_irg_visited(current_ir_graph);
+ env.visited_nr = get_irg_visited(current_ir_graph);
+
+ copy_block = find_candidate(&env, projx, selector);
+ if (copy_block == NULL)
+ return;
+
+ /* 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;
+
+ /* shorten Phis */
+ foreach_out_edge_safe(env.cnst_pred, edge, next) {
+ ir_node *node = get_edge_src_irn(edge);
+
+ 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_jumpthreading(ir_graph* irg)
+{
+ int changed, rerun;
+
+ FIRM_DBG_REGISTER(dbg, "firm.opt.jumpthreading");
+
+ DB((dbg, LEVEL_1, "===> Performing jumpthreading on %+F\n", irg));
+
+ remove_critical_cf_edges(irg);
+
+ edges_assure(irg);
+ ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
+
+ changed = 0;
+ do {
+ rerun = 0;
+ irg_block_walk_graph(irg, thread_jumps, NULL, &rerun);
+ changed |= rerun;
+ } while (rerun);
+
+ ir_free_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_IRN_VISITED);
+
+ 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);
+ set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
+
+ /* Dead code might be created. Optimize it away as it is dangerous
+ * to call optimize_df() an dead code. */
+ optimize_cf(irg);
+ }
+}
projects / libfirm / commitdiff