+/*
+ * Copyright (C) 1995-2007 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 <assert.h>
-#include <alloca.h>
#include "array.h"
+#include "condeval.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"
DEBUG_ONLY(static firm_dbg_module_t *dbg);
-static void cond_eval(ir_node* block, void* env)
+/**
+ * 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)
{
- int n_block = get_Block_n_cfgpreds(block);
+ ir_node** ins;
+ int n;
int i;
- for (i = 0; i < n_block; i++) {
- ir_node* pred;
- ir_node* projx;
- ir_node* cond;
- ir_node* cmp;
- ir_node* left;
- ir_node* right;
- ir_node* cond_block;
- ir_node* phi;
- ir_node* cnst;
- pn_Cmp pnc;
- int n_phi;
- int j;
-
- pred = get_Block_cfgpred(block, i);
- if (!is_Proj(pred)) continue;
- projx = pred;
-
- pred = get_Proj_pred(projx);
- if (!is_Cond(pred)) continue;
- cond = pred;
-
- pred = get_Cond_selector(cond);
- assert(is_Proj(pred));
- // TODO handle switches
- if (get_irn_mode(pred) != mode_b) continue;
- pnc = get_Proj_proj(pred);
-
- cmp = get_Proj_pred(pred);
- assert(is_Cmp(cmp));
-
- left = get_Cmp_left(cmp);
- right = get_Cmp_right(cmp);
-
- // TODO handle Const-Const and Phi-Phi
- if (is_Phi(left)) {
- if (!is_Const(right)) continue;
- phi = left;
- cnst = right;
- } else if (is_Phi(right)) {
- if (!is_Const(left)) continue;
- phi = right;
- cnst = left;
- pnc = get_inversed_pnc(pnc);
- } else {
+ 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 *search_def_and_create_phis(ir_node *block, ir_mode *mode)
+{
+ 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();
+
+ // already processed this block?
+ if(irn_visited(block)) {
+ ir_node *value = (ir_node*) get_irn_link(block);
+ return value;
+ }
+
+ // 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);
+
+ 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);
+
+ irg = get_irn_irg(block);
+ phi = new_r_Phi(irg, block, n_cfgpreds, in, mode);
+ set_irn_link(block, phi);
+ mark_irn_visited(block);
+
+ // set phi preds
+ 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);
+
+ 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 * const *blocks, ir_node * const *vals, int n_vals)
+{
+ int i;
+ ir_graph *irg;
+ ir_mode *mode;
+ const ir_edge_t *edge;
+ const ir_edge_t *next;
+ ir_node *value;
+
+ assert(n_vals > 0);
+
+ irg = get_irn_irg(vals[0]);
+ inc_irg_visited(irg);
+
+ mode = get_irn_mode(vals[0]);
+ for(i = 0; i < n_vals; ++i) {
+ ir_node *value = vals[i];
+ ir_node *value_block = blocks[i];
+
+ assert(get_irn_mode(value) == mode);
+
+ set_irn_link(value_block, value);
+ mark_irn_visited(value_block);
+ }
+
+ // 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);
+ ir_node *user_block = get_nodes_block(user);
+ ir_node *newval;
+
+ // ignore keeps
+ if(get_irn_op(user) == op_End)
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);
+ } else {
+ newval = search_def_and_create_phis(user_block, mode);
+ }
+
+ // 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(irg, new_block);
+ 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;
+
+ 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) {
+ const ir_edge_t *edge;
- cond_block = get_nodes_block(cond);
- if (get_nodes_block(phi) != cond_block) continue;
-
- if (get_Proj_proj(projx) == 0) pnc = get_negated_pnc(pnc, get_irn_mode(cnst));
-
- n_phi = get_Phi_n_preds(phi);
- for (j = 0; j < n_phi; j++) {
- tarval* tv_phi;
- tarval* tv_cnst;
- ir_node** ins;
- int k;
-
- pred = get_Phi_pred(phi, j);
- // TODO handle Phi cascades
- if (!is_Const(pred)) continue;
-
- tv_phi = get_Const_tarval(pred);
- tv_cnst = get_Const_tarval(cnst);
-
- switch (tarval_cmp(tv_phi, tv_cnst)) {
- case pn_Cmp_Lt:
- if (pnc != pn_Cmp_Lt &&
- pnc != pn_Cmp_Le &&
- pnc != pn_Cmp_Lg) {
- continue;
- }
- break;
-
- case pn_Cmp_Eq:
- if (pnc != pn_Cmp_Le &&
- pnc != pn_Cmp_Ge &&
- pnc != pn_Cmp_Eq) {
- continue;
- }
- break;
-
- case pn_Cmp_Gt:
- if (pnc != pn_Cmp_Gt &&
- pnc != pn_Cmp_Ge &&
- pnc != pn_Cmp_Lg) {
- continue;
- }
- break;
-
- default: continue;
+ /* 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 = get_irn_mode(node);
+
+ /* ignore control flow */
+ if (mode == mode_X || is_Cond(node))
+ continue;
+ /* 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;
+
+ 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;
+ }
- DB((
- dbg, LEVEL_1,
- "> Found condition evaluation candidate %+F->%+F predecessor %d\n",
- block, cond_block, j
- ));
+ /* 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);
+ }
-#if 0 // TODO repair data flow and dominance
- NEW_ARR_A(ir_node*, ins, n_block + 1);
- for (k = 0; k < n_block; k++) ins[k] = get_Block_cfgpred(block, k);
- ins[k] = get_Block_cfgpred(cond_block, j);
- set_irn_in(block, n_block + 1, ins);
+ set_irn_link(node, copy);
+ set_irn_visited(node, env->visited_nr);
- set_Block_cfgpred(cond_block, j, new_Bad());
- set_Phi_pred(phi, j, new_Bad());
-#endif
+ /* 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 *vals[2];
+ ir_node *blocks[2];
+ ir_node *node = get_edge_src_irn(edge);
+ ir_mode *mode = get_irn_mode(node);
+
+ if (mode == mode_X || is_Cond(node))
+ continue;
+ if (mode == mode_b)
+ continue;
+
+ DB((dbg, LEVEL_2, ">> Fixing users of %+F\n", node));
+
+ blocks[0] = block;
+ vals[0] = node;
+ blocks[1] = copy_block;
+ vals[1] = get_irn_link(node);
+ construct_ssa(blocks, vals, 2);
+ }
+}
+
+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;
+ 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) {
+ ir_node *block = get_nodes_block(jump);
+
+ if(irn_visited(value))
+ return NULL;
+ mark_irn_visited(value);
+
+ if(is_Const(value)) {
+ tarval *tv_const = get_Const_tarval(env->cnst);
+ tarval *tv = get_Const_tarval(value);
+
+ if(!eval_cmp(env->pnc, tv, tv_const))
+ 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 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_phi_with_const(cfgpred, phi_pred, env);
+ if(copy_block == NULL)
+ continue;
+
+ /* copy duplicated nodes in copy_block and fix SSA */
+ copy_and_fix(block, copy_block, i, env);
+
+ 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;
}
+/**
+ * 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_graph *irg = current_ir_graph;
+ ir_node *copy_block;
+ ir_node *pred;
+ ir_node *projx;
+ ir_node *cond;
+ ir_node *cmp;
+ ir_node *left;
+ ir_node *right;
+ ir_node *cond_block;
+ pn_Cmp pnc;
+
+ 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;
+
+ pred = get_Cond_selector(cond);
+ // TODO handle switches
+ if (get_irn_mode(pred) != 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));
+ }
+
+ /* 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;
+
+ 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);
+ *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;
+
+ // (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;
+ ir_node* bad = new_Bad();
+ size_t 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));
- irg_block_walk_graph(irg, NULL, cond_eval, NULL);
+ remove_critical_cf_edges(irg);
+ normalize_proj_nodes(irg);
+
+ edges_assure(irg);
+ set_using_irn_link(irg);
+ set_using_visited(irg);
+
+ changed = 0;
+ do {
+ 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_doms_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+ set_irg_loopinfo_inconsistent(irg);
+ }
+
+ clear_using_visited(irg);
+ clear_using_irn_link(irg);
}
projects / libfirm / blobdiff