+
+/**
+ * Walker: collect Phi nodes and mark
+ */
+static void collect_phis(ir_node *node, void *env)
+{
+ (void) env;
+
+ if (is_Phi(node)) {
+ ir_node *block = get_nodes_block(node);
+ add_Block_phi(block, node);
+ return;
+ }
+
+ /* Ignore control flow nodes, these will be removed. */
+ if (get_irn_pinned(node) == op_pin_state_pinned &&
+ !is_Block(node) && !is_cfop(node)) {
+ /* found a pinned non-cf node, mark its block */
+ ir_node *block = get_nodes_block(node);
+ set_Block_mark(block, 1);
+ }
+}
+
+/**
+ * If node is a Jmp in a block containing no pinned instruction
+ * and having only one predecessor, skip the block and return its
+ * cf predecessor, else the node itself.
+ */
+static ir_node *skip_empty_blocks(ir_node *node)
+{
+ while (is_Jmp(node)) {
+ ir_node *block = get_nodes_block(node);
+
+ if (get_Block_n_cfgpreds(block) != 1)
+ break;
+
+ if (get_Block_mark(block))
+ break;
+
+ node = get_Block_cfgpred(block, 0);
+ }
+ return node;
+}
+
+/**
+ * Check if two block inputs can be fused.
+ * This can be done, if block contains no Phi node that depends on
+ * different inputs idx_i and idx_j.
+ */
+static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j) {
+ const ir_node *phi;
+
+ for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
+ if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
+ return 0;
+ }
+ return 1;
+}
+
+/**
+ * Remove block input with given index.
+ */
+static void remove_block_input(ir_node *block, int idx)
+{
+ int i, j, n = get_Block_n_cfgpreds(block) - 1;
+ ir_node *phi, **ins;
+
+ NEW_ARR_A(ir_node *, ins, n);
+
+ if (n == 1) {
+ /* all Phis will be deleted */
+ ir_node *next_phi;
+
+ for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
+ next_phi = get_Phi_next(phi);
+ exchange(phi, get_Phi_pred(phi, idx ^ 1));
+ }
+ set_Block_phis(block, NULL);
+ } else {
+ for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
+ for (i = j = 0; i <= n; ++i) {
+ if (i != idx)
+ ins[j++] = get_Phi_pred(phi, i);
+ }
+ set_irn_in(phi, n, ins);
+ }
+ }
+ for (i = j = 0; i <= n; ++i) {
+ if (i != idx)
+ ins[j++] = get_Block_cfgpred(block, i);
+ }
+ set_irn_in(block, n, ins);
+}
+
+/**
+ * Under the preposition that we have a chain of blocks from
+ * from_block to to_block, collapse them all into to_block.
+ */
+static void move_nodes_to_block(ir_node *jmp, ir_node *to_block) {
+ ir_node *new_jmp = NULL;
+ ir_node *block, *next_block;
+
+ for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
+ new_jmp = get_Block_cfgpred(block, 0);
+ next_block = get_nodes_block(new_jmp);
+ exchange(block, to_block);
+ }
+ if (new_jmp)
+ exchange(jmp, new_jmp);
+}
+
+/**
+ * Block walker:
+ *
+ * if we can find the following structure,
+ *
+ * upper_block
+ * / |
+ * / |
+ * lower_block |
+ * / \ |
+ * ... low_idx up_idx
+ * \ |
+ * block
+ *
+ * try to convert it into a (x pnc_lo c_lo) || (x pnc_hi c_hi)
+ * and optimize.
+ */
+static void find_cf_and_or_walker(ir_node *block, void *ctx)
+{
+ int low_idx, up_idx;
+ int n_cfgpreds = get_Block_n_cfgpreds(block);
+ bool_opt_env_t *env = ctx;
+
+restart:
+ if (n_cfgpreds < 2)
+ return;
+
+ for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
+ ir_node *lower_block;
+ ir_node *lower_cf;
+ ir_node *cond;
+ ir_node *cond_selector;
+ ir_node *lower_pred;
+
+ lower_cf = get_Block_cfgpred(block, low_idx);
+ lower_cf = skip_empty_blocks(lower_cf);
+ if (!is_Proj(lower_cf))
+ continue;
+
+ cond = get_Proj_pred(lower_cf);
+ if (!is_Cond(cond))
+ continue;
+
+ lower_block = get_nodes_block(cond);
+ if (get_Block_n_cfgpreds(lower_block) != 1)
+ continue;
+
+ /* the block must not produce any side-effects */
+ if (get_Block_mark(lower_block))
+ continue;
+
+ cond_selector = get_Cond_selector(cond);
+ if (get_irn_mode(cond_selector) != mode_b)
+ continue;
+
+ lower_pred = get_Block_cfgpred_block(lower_block, 0);
+
+ for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
+ ir_node *upper_block;
+ ir_node *upper_cf;
+ ir_node *upper_cond;
+ ir_node *upper_cond_selector;
+ ir_node *replacement;
+ cond_pair cpair;
+
+ upper_cf = get_Block_cfgpred(block, up_idx);
+ upper_cf = skip_empty_blocks(upper_cf);
+ if (is_Bad(upper_cf))
+ continue;
+ upper_block = get_nodes_block(upper_cf);
+ if (upper_block != lower_pred)
+ continue;
+ if (!block_dominates(upper_block, block))
+ continue;
+
+ assert(is_Proj(upper_cf));
+ upper_cond = get_Proj_pred(upper_cf);
+ assert(is_Cond(upper_cond));
+ upper_cond_selector = get_Cond_selector(upper_cond);
+ if (get_irn_mode(upper_cond_selector) != mode_b)
+ continue;
+
+ /* we have found the structure */
+ /* check Phis: There must be NO Phi in block that
+ depends on the existence of low block */
+ if (!can_fuse_block_inputs(block, low_idx, up_idx))
+ continue;
+
+ /* all fine, try it */
+ if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
+ continue;
+
+ /* normalize pncs: we need the true case to jump into the
+ * common block (ie. conjunctive normal form) */
+ if (get_Proj_proj(lower_cf) == pn_Cond_false) {
+ if (cpair.proj_lo == cond_selector) {
+ ir_mode *mode = get_tarval_mode(cpair.tv_lo);
+ ir_node *cmp = get_Proj_pred(cpair.proj_lo);
+ ir_node *block = get_nodes_block(cmp);
+ cpair.pnc_lo = get_negated_pnc(cpair.pnc_lo, mode);
+ cpair.proj_lo = new_r_Proj(block, cmp, mode_b, cpair.pnc_lo);
+ } else {
+ ir_mode *mode = get_tarval_mode(cpair.tv_hi);
+ ir_node *cmp = get_Proj_pred(cpair.proj_hi);
+ ir_node *block = get_nodes_block(cmp);
+ assert(cpair.proj_hi == cond_selector);
+ cpair.pnc_hi = get_negated_pnc(cpair.pnc_hi, mode);
+ cpair.proj_hi = new_r_Proj(block, cmp, mode_b, cpair.pnc_hi);
+ }
+ }
+ if (get_Proj_proj(upper_cf) == pn_Cond_false) {
+ if (cpair.proj_lo == upper_cond_selector) {
+ ir_mode *mode = get_tarval_mode(cpair.tv_lo);
+ ir_node *cmp = get_Proj_pred(cpair.proj_lo);
+ ir_node *block = get_nodes_block(cmp);
+ cpair.pnc_lo = get_negated_pnc(cpair.pnc_lo, mode);
+ cpair.proj_lo = new_r_Proj(block, cmp, mode_b, cpair.pnc_lo);
+ } else {
+ ir_mode *mode = get_tarval_mode(cpair.tv_hi);
+ ir_node *cmp = get_Proj_pred(cpair.proj_hi);
+ ir_node *block = get_nodes_block(cmp);
+ assert(cpair.proj_hi == upper_cond_selector);
+ cpair.pnc_hi = get_negated_pnc(cpair.pnc_hi, mode);
+ cpair.proj_hi = new_r_Proj(block, cmp, mode_b, cpair.pnc_hi);
+ }
+ }
+
+ /* can we optimize the case? */
+ replacement = bool_or(&cpair, upper_block);
+ if (replacement == NULL)
+ continue;
+
+ env->changed = 1;
+
+ DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
+ current_ir_graph, upper_block, lower_block));
+
+ /* move all expressions on the path to lower/upper block */
+ move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
+ move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
+
+ /* move all nodes from lower block to upper block */
+ exchange(lower_block, upper_block);
+
+ remove_block_input(block, up_idx);
+ --n_cfgpreds;
+
+ /* the optimizations expected the true case to jump */
+ if (get_Proj_proj(lower_cf) == pn_Cond_false) {
+ ir_node *block = get_nodes_block(replacement);
+ replacement = new_rd_Not(NULL, block, replacement, mode_b);
+ }
+ set_Cond_selector(cond, replacement);
+
+ goto restart;
+ }
+ }
+}
+
+void opt_bool(ir_graph *const irg)
+{
+ bool_opt_env_t env;
+
+ /* register a debug mask */
+ FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
+
+ /* works better with one return block only */
+ normalize_one_return(irg);
+
+ env.changed = 0;
+
+ /* optimize simple Andb and Orb cases */
+ irg_walk_graph(irg, NULL, bool_walk, &env);
+
+ ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
+
+ /* now more complicated cases: find control flow And/Or and optimize. */
+ irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
+ irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
+
+ if (env.changed) {
+ set_irg_outs_inconsistent(irg);
+ set_irg_doms_inconsistent(irg);
+ set_irg_extblk_inconsistent(irg);
+ set_irg_loopinfo_inconsistent(irg);
+ }
+
+ ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
+}
+
+/* Creates an ir_graph pass for opt_bool. */
+ir_graph_pass_t *opt_bool_pass(const char *name)
+{
+ return def_graph_pass(name ? name : "opt_bool", opt_bool);
+} /* opt_bool_pass */