X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fcfopt.c;h=4e5cc69058ea8e84c411a09031a9adbdb98638b7;hb=d652537f11d5c3262930cc7f4962c5b1858e649a;hp=f5f8799672af7a8ca1cefd85d4f78bee14f486b6;hpb=d582838a2939e14c38453d5397af829ff588ecfe;p=libfirm diff --git a/ir/opt/cfopt.c b/ir/opt/cfopt.c index f5f879967..4e5cc6905 100644 --- a/ir/opt/cfopt.c +++ b/ir/opt/cfopt.c @@ -1,20 +1,35 @@ /* - * Project: libFIRM - * File name: ir/opt/cfopt.c - * Purpose: control flow optimizations - * Author: - * Created: - * CVS-ID: $Id$ - * Copyright: (c) 1998-2004 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 Control flow optimizations. + * @author Goetz Lindenmaier, Michael Beck, Sebastian Hack + * @version $Id$ */ +#include "config.h" -#ifdef HAVE_CONFIG_H -# include "config.h" -#endif +#include "iroptimize.h" #include +#include "plist.h" #include "xmalloc.h" #include "irnode_t.h" #include "irgraph_t.h" @@ -26,8 +41,9 @@ #include "irgmod.h" #include "irdump.h" #include "irvrfy.h" +#include "iredges.h" -#include "array.h" +#include "array_t.h" #include "irouts.h" #include "irbackedge_t.h" @@ -35,7 +51,6 @@ #include "irflag_t.h" #include "firmstat.h" -#include "cfopt.h" #include "iropt_dbg.h" /*------------------------------------------------------------------*/ @@ -45,8 +60,14 @@ /* is empty if it contains only a Jmp node. */ /* Blocks can only be removed if they are not needed for the */ /* semantics of Phi nodes. */ +/* Further, we NEVER remove labeled blocks (even if we could move */ +/* the label. */ /*------------------------------------------------------------------*/ +#define set_Block_removable(block) set_Block_mark(block, 1) +#define set_Block_non_removable(block) set_Block_mark(block, 0) +#define is_Block_removable(block) (get_Block_mark(block) != 0) + /** * Replace binary Conds that jumps twice into the same block * by a simple Jmp. @@ -64,36 +85,43 @@ * Note that the simple case that Block has only these two * predecessors are already handled in equivalent_node_Block(). */ -static void remove_senseless_conds(ir_node *bl, void *data) -{ - int i, j; - int n = get_Block_n_cfgpreds(bl); - - assert(is_Block(bl)); - - for (i = 0; i < n; ++i) { - ir_node *pred_i = get_Block_cfgpred(bl, i); - ir_node *cond_i = skip_Proj(pred_i); - - for (j = i + 1; j < n; ++j) { - ir_node *pred_j = get_Block_cfgpred(bl, j); - ir_node *cond_j = skip_Proj(pred_j); - - if (cond_j == cond_i - && get_irn_op(cond_i) == op_Cond - && get_irn_mode(get_Cond_selector(cond_i)) == mode_b) { - - ir_node *jmp = new_r_Jmp(current_ir_graph, get_nodes_block(cond_i)); - set_irn_n(bl, i, jmp); - set_irn_n(bl, j, new_Bad()); - - DBG_OPT_IFSIM2(cond_i, jmp); - break; - } - } - } +static int remove_senseless_conds(ir_node *bl) { + int i, j; + int n = get_Block_n_cfgpreds(bl); + int changed = 0; + + for (i = 0; i < n; ++i) { + ir_node *pred_i = get_Block_cfgpred(bl, i); + ir_node *cond_i = skip_Proj(pred_i); + + /* binary Cond */ + if (is_Cond(cond_i) && get_irn_mode(get_Cond_selector(cond_i)) == mode_b) { + + for (j = i + 1; j < n; ++j) { + ir_node *pred_j = get_Block_cfgpred(bl, j); + ir_node *cond_j = skip_Proj(pred_j); + + if (cond_j == cond_i) { + ir_node *jmp = new_r_Jmp(current_ir_graph, get_nodes_block(cond_i)); + set_irn_n(bl, i, jmp); + set_irn_n(bl, j, new_Bad()); + + DBG_OPT_IFSIM2(cond_i, jmp); + changed = 1; + break; + } + } + } + } + return changed; } +/** An environment for merge_blocks and collect nodes. */ +typedef struct _merge_env { + int changed; /**< Set if the graph was changed. */ + int phis_moved; /**< Set if Phi nodes were moved. */ + plist_t *list; /**< Helper list for all found Switch Conds. */ +} merge_env; /** * Removes Tuples from Block control flow predecessors. @@ -102,115 +130,160 @@ static void remove_senseless_conds(ir_node *bl, void *data) * Therefore we also optimize at control flow operations, depending * how we first reach the Block. */ -static void merge_blocks(ir_node *n, void *env) { - int i; - ir_node *new_block; - - /* clear the link field for ALL nodes first */ - set_irn_link(n, NULL); - - if (get_irn_op(n) == op_Block) { - /* Remove Tuples */ - for (i = 0; i < get_Block_n_cfgpreds(n); i++) { - /* GL @@@ : is this possible? if (get_opt_normalize()) -- added, all tests go through. - A different order of optimizations might cause problems. */ - if (get_opt_normalize()) - set_Block_cfgpred(n, i, skip_Tuple(get_Block_cfgpred(n, i))); - } - - /* see below */ - new_block = equivalent_node(n); - if (new_block != n && ! is_Block_dead(new_block)) - exchange (n, new_block); - - } else if (get_opt_optimize() && (get_irn_mode(n) == mode_X)) { - /* We will soon visit a block. Optimize it before visiting! */ - ir_node *b = get_nodes_block(skip_Proj(n)); - - if (!is_Block_dead(b)) { - new_block = equivalent_node(b); - - while (irn_not_visited(b) && (!is_Block_dead(new_block)) && (new_block != b)) { - /* We would have to run gigo() if new is bad, so we - promote it directly below. Nevertheless, we sometimes reach a block - the first time through a dataflow node. In this case we optimized the - block as such and have to promote the Bad here. */ - assert((get_opt_control_flow_straightening() || - get_opt_control_flow_weak_simplification()) && - ("strange flag setting")); - exchange (b, new_block); - b = new_block; - new_block = equivalent_node(b); - } - - /* normally, we would create a Bad block here, but this must be - * prevented, so just set it's cf to Bad. - */ - if (is_Block_dead(new_block)) - exchange(n, new_Bad()); - } - } +static void merge_blocks(ir_node *node, void *ctx) { + int i; + ir_node *new_block; + merge_env *env = ctx; + + /* clear the link field for ALL nodes first */ + set_irn_link(node, NULL); + + if (is_Block(node)) { + /* Remove Tuples */ + for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) { + ir_node *pred = get_Block_cfgpred(node, i); + ir_node *skipped = skip_Tuple(pred); + if (pred != skipped) { + set_Block_cfgpred(node, i, skipped); + env->changed = 1; + } + } + + /* see below */ + new_block = equivalent_node(node); + if (new_block != node && ! is_Block_dead(new_block)) { + exchange(node, new_block); + env->changed = 1; + } + + } else if (get_opt_optimize() && (get_irn_mode(node) == mode_X)) { + /* We will soon visit a block. Optimize it before visiting! */ + ir_node *b = get_nodes_block(skip_Proj(node)); + + if (!is_Block_dead(b)) { + new_block = equivalent_node(b); + + while (!irn_visited(b) && !is_Block_dead(new_block) && new_block != b) { + /* We would have to run gigo() if new is bad, so we + promote it directly below. Nevertheless, we sometimes reach a block + the first time through a dataflow node. In this case we optimized the + block as such and have to promote the Bad here. */ + assert((get_opt_control_flow_straightening() || + get_opt_control_flow_weak_simplification()) && + ("strange flag setting")); + exchange(b, new_block); + env->changed = 1; + b = new_block; + new_block = equivalent_node(b); + } + + /* normally, we would create a Bad block here, but this must be + * prevented, so just set it's cf to Bad. + */ + if (is_Block_dead(new_block)) { + exchange(node, new_Bad()); + env->changed = 1; + } + } + } } /** - * Remove cf from dead block by inspecting dominance info + * Block walker removing control flow from dead block by + * inspecting dominance info. * Do not replace blocks by Bad. This optimization shall * ensure, that all Bad control flow predecessors are * removed, and no new other Bads are introduced. + * Further removed useless Conds and clear the mark of all blocks. * * Must be run in the post walker. */ -static void remove_dead_block_cf(ir_node *block, void *env) -{ - int i, n; - - /* check block predecessors and turn control flow into bad */ - for (i = 0, n = get_Block_n_cfgpreds(block); i < n; ++i) { - ir_node *pred_X = get_Block_cfgpred(block, i); - - if (! is_Bad(pred_X)) { - ir_node *pred_bl = get_nodes_block(skip_Proj(pred_X)); - - if (is_Block_dead(pred_bl) || (get_Block_dom_depth(pred_bl) < 0)) - exchange (pred_X, new_Bad()); - } - } +static void remove_unreachable_blocks_and_conds(ir_node *block, void *env) { + int i; + int *changed = env; + + /* Check block predecessors and turn control flow into bad. + Beware of Tuple, kill them. */ + for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) { + ir_node *pred_X = get_Block_cfgpred(block, i); + ir_node *skipped = skip_Tuple(pred_X); + + if (! is_Bad(skipped)) { + ir_node *pred_bl = get_nodes_block(skip_Proj(skipped)); + + if (is_Block_dead(pred_bl) || (get_Block_dom_depth(pred_bl) < 0)) { + set_Block_dead(pred_bl); + exchange(pred_X, new_Bad()); + *changed = 1; + } else if (skipped != pred_X) { + set_Block_cfgpred(block, i, skipped); + *changed = 1; + } + } + } + + *changed |= remove_senseless_conds(block); + + /* clear the block mark of all non labeled blocks */ + if (has_Block_label(block)) + set_Block_non_removable(block); + else + set_Block_removable(block); } /** * Collects all Phi nodes in link list of Block. - * Marks all blocks "block_visited" if they contain a node other - * than Jmp. - * Replaces n by Bad if n is unreachable control flow. We do that - * in the post walker, so we catch all blocks. + * Marks all blocks "non_removable" if they contain a node other + * than Jmp (and Proj). + * Links all Proj nodes to their predecessors. + * Collects all switch-Conds in a list. */ -static void collect_nodes(ir_node *n, void *env) { - if (is_no_Block(n)) { - ir_node *b = get_nodes_block(n); - - if ((get_irn_op(n) == op_Phi)) { - /* Collect Phi nodes to compact ins along with block's ins. */ - set_irn_link(n, get_irn_link(b)); - set_irn_link(b, n); - } - else if ((get_irn_op(n) != op_Jmp) && !is_Bad(b)) { /* Check for non empty block. */ - mark_Block_block_visited(b); - } - } +static void collect_nodes(ir_node *n, void *ctx) { + ir_opcode code = get_irn_opcode(n); + merge_env *env = ctx; + + if (code == iro_Block) { + /* mark the block as non-removable if it is labeled */ + if (has_Block_label(n)) + set_Block_non_removable(n); + } else { + ir_node *b = get_nodes_block(n); + + if (code == iro_Phi && get_irn_arity(n) > 0) { + /* Collect Phi nodes to compact ins along with block's ins. */ + set_irn_link(n, get_irn_link(b)); + set_irn_link(b, n); + } else if (code != iro_Jmp && !is_Bad(b)) { /* Check for non-empty block. */ + set_Block_non_removable(b); + + if (code == iro_Proj) { /* link Proj nodes */ + ir_node *pred = get_Proj_pred(n); + + set_irn_link(n, get_irn_link(pred)); + set_irn_link(pred, n); + } else if (code == iro_Cond) { + ir_node *sel = get_Cond_selector(n); + if (mode_is_int(get_irn_mode(sel))) { + /* found a switch-Cond, collect */ + plist_insert_back(env->list, n); + } + } + } + } } /** Returns true if pred is predecessor of block. */ static int is_pred_of(ir_node *pred, ir_node *b) { - int i, n; - - for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) { - ir_node *b_pred = get_nodes_block(get_Block_cfgpred(b, i)); - if (b_pred == pred) return 1; - } - return 0; + int i; + + for (i = get_Block_n_cfgpreds(b) - 1; i >= 0; --i) { + ir_node *b_pred = get_Block_cfgpred_block(b, i); + if (b_pred == pred) + return 1; + } + return 0; } - /** Test whether we can optimize away pred block pos of b. * * @param b A block node. @@ -239,69 +312,57 @@ static int is_pred_of(ir_node *pred, ir_node *b) { * as already removed. **/ static int test_whether_dispensable(ir_node *b, int pos) { - int i, j, n_preds = 1; - ir_node *pred = get_Block_cfgpred_block(b, pos); - - /* Bad blocks will be optimized away, so we don't need space for them */ - if (is_Block_dead(pred)) - return 0; - - if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { - - if (!get_opt_optimize() || !get_opt_control_flow_strong_simplification()) { - /* Mark block so that is will not be removed: optimization is turned off. */ - set_Block_block_visited(pred, get_irg_block_visited(current_ir_graph)-1); - return 1; - } - - /* Seems to be empty. At least we detected this in collect_nodes. */ - if (!get_irn_link(b)) { - /* There are no Phi nodes ==> all predecessors are dispensable. */ - n_preds = get_Block_n_cfgpreds(pred); - } else { - /* b's pred blocks and pred's pred blocks must be pairwise disjunct. - Handle all pred blocks with preds < pos as if they were already removed. */ - for (i = 0; i < pos; i++) { - ir_node *b_pred = get_Block_cfgpred_block(b, i); - if (! is_Block_dead(b_pred) && - get_Block_block_visited(b_pred) + 1 - < get_irg_block_visited(current_ir_graph)) { - for (j = 0; j < get_Block_n_cfgpreds(b_pred); j++) { - ir_node *b_pred_pred = get_Block_cfgpred_block(b_pred, j); - if (is_pred_of(b_pred_pred, pred)) - goto non_dispensable; - } - } else { - if (is_pred_of(b_pred, pred)) - goto non_dispensable; - } - } - for (i = pos +1; i < get_Block_n_cfgpreds(b); i++) { - ir_node *b_pred = get_Block_cfgpred_block(b, i); - if (is_pred_of(b_pred, pred)) - goto non_dispensable; - } - /* if we get here, the block is dispensable */ - n_preds = get_Block_n_cfgpreds(pred); - } - } - - return n_preds; + int i, j, n_preds = 1; + ir_node *pred = get_Block_cfgpred_block(b, pos); + + /* Bad blocks will be optimized away, so we don't need space for them */ + if (is_Block_dead(pred)) + return 0; + + if (is_Block_removable(pred)) { + if (!get_opt_optimize() || !get_opt_control_flow_strong_simplification()) { + /* Mark block so that is will not be removed: optimization is turned off. */ + set_Block_non_removable(pred); + return 1; + } + + /* Seems to be empty. At least we detected this in collect_nodes. */ + if (get_irn_link(b) == NULL) { + /* There are no Phi nodes ==> all predecessors are dispensable. */ + n_preds = get_Block_n_cfgpreds(pred); + } else { + /* b's pred blocks and pred's pred blocks must be pairwise disjunct. + Handle all pred blocks with preds < pos as if they were already removed. */ + for (i = 0; i < pos; i++) { + ir_node *b_pred = get_Block_cfgpred_block(b, i); + if (! is_Block_dead(b_pred) && is_Block_removable(b_pred)) { + for (j = get_Block_n_cfgpreds(b_pred) - 1; j >= 0; --j) { + ir_node *b_pred_pred = get_Block_cfgpred_block(b_pred, j); + if (is_pred_of(b_pred_pred, pred)) + goto non_dispensable; + } + } else { + if (is_pred_of(b_pred, pred)) + goto non_dispensable; + } + } + for (i = pos +1; i < get_Block_n_cfgpreds(b); i++) { + ir_node *b_pred = get_Block_cfgpred_block(b, i); + if (is_pred_of(b_pred, pred)) + goto non_dispensable; + } + /* if we get here, the block is dispensable */ + n_preds = get_Block_n_cfgpreds(pred); + } + } + + return n_preds; non_dispensable: - set_Block_block_visited(pred, get_irg_block_visited(current_ir_graph)-1); - return 1; + set_Block_non_removable(pred); + return 1; } -/** - * Store to defer the exchanged of Phi nodes. - */ -typedef struct _defer_ex_phi { - ir_node *phi_pred; /**< the previous Phi node that will be replaced */ - ir_node *phi; /**< the new Phi node that replaces phi_pred */ -} defer_ex_phi; - /** * This method removed Bad cf predecessors from Blocks and Phis, and removes * empty blocks. A block is empty if it only contains Phi and Jmp nodes. @@ -349,236 +410,270 @@ typedef struct _defer_ex_phi { * @@@ It is negotiable whether we should do this ... there might end up a copy * from the Phi in the loop when removing the Phis. */ -static void optimize_blocks(ir_node *b, void *env) { - int i, j, k, n, max_preds, n_preds, p_preds; - ir_node *pred, *phi; - ir_node **in; - defer_ex_phi *defers; - - /* Count the number of predecessor if this block is merged with pred blocks - that are empty. */ - max_preds = 0; - for (i = 0, k = get_Block_n_cfgpreds(b); i < k; ++i) { - max_preds += test_whether_dispensable(b, i); - } - in = xmalloc(max_preds * sizeof(*in)); - - defers = NEW_ARR_F(defer_ex_phi, 0); - -/*- - printf(" working on "); DDMN(b); - for (i = 0; i < get_Block_n_cfgpreds(b); i++) { - pred = get_nodes_block(get_Block_cfgpred(b, i)); - if (is_Bad(get_Block_cfgpred(b, i))) { - printf(" removing Bad %i\n ", i); - } else if (get_Block_block_visited(pred) +1 - < get_irg_block_visited(current_ir_graph)) { - printf(" removing pred %i ", i); DDMN(pred); - } else { printf(" Nothing to do for "); DDMN(pred); } - } - * end Debug output -*/ - - /*- Fix the Phi nodes of the current block -*/ - for (phi = get_irn_link(b); phi; ) { - assert(get_irn_op(phi) == op_Phi); - - /* Find the new predecessors for the Phi */ - p_preds = 0; - for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) { - pred = get_Block_cfgpred_block(b, i); - - if (is_Bad(get_Block_cfgpred(b, i))) { - /* case Phi 1: Do nothing */ - } - else if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { - /* case Phi 2: It's an empty block and not yet visited. */ - ir_node *phi_pred = get_Phi_pred(phi, i); - - for (j = 0, k = get_Block_n_cfgpreds(pred); j < k; j++) { - /* because of breaking loops, not all predecessors are Bad-clean, - * so we must check this here again */ - if (! is_Bad(get_Block_cfgpred(pred, j))) { - if (get_nodes_block(phi_pred) == pred) { - /* case Phi 2a: */ - assert(get_irn_op(phi_pred) == op_Phi); /* Block is empty!! */ - - in[p_preds++] = get_Phi_pred(phi_pred, j); - } else { - /* case Phi 2b: */ - in[p_preds++] = phi_pred; - } - } - } - - /* The Phi_pred node is replaced now if it is a Phi. - - Somehow the removed Phi node can be used legally in loops. - Therefore we replace the old phi by the new one. - This must be done _AFTER_ all Phis are optimized, or - it will fail if two Phis use the same pred_Phi. - - FIXME: Is the following true? We ALWAYS replace it by the new one. - - Further we have to remove the old Phi node by replacing it - by Bad. Else it will remain in the keep alive array of End - and cause illegal situations. So if there is no loop, we should - replace it by Bad. - */ - if (get_nodes_block(phi_pred) == pred) { - int i; - /* remove the Phi as it might be kept alive. Further there - might be other users. */ - for (i = ARR_LEN(defers) - 1; i >= 0; --i) - if (defers[i].phi_pred == phi_pred) - break; - - if (i < 0) { - /* we have a new replacement */ - defer_ex_phi elem; - - elem.phi_pred = phi_pred; - elem.phi = phi; - ARR_APP1(defer_ex_phi, defers, elem); - } - } - } else { - /* case Phi 3: */ - in[p_preds++] = get_Phi_pred(phi, i); - } - } - assert(p_preds <= max_preds); - - /* Fix the node */ - if (p_preds == 1) - /* By removal of Bad ins the Phi might be degenerated. */ - exchange(phi, in[0]); - else - set_irn_in(phi, p_preds, in); - - phi = get_irn_link(phi); - } - - /* now, exchange all Phis */ - for (i = ARR_LEN(defers) - 1; i >= 0; --i) { - exchange(defers[i].phi_pred, defers[i].phi); - } - DEL_ARR_F(defers); - - /*- This happens only if merge between loop backedge and single loop entry. - See special case above. -*/ - for (k = 0, n = get_Block_n_cfgpreds(b); k < n; ++k) { - pred = get_nodes_block(get_Block_cfgpred(b, k)); - - if (get_Block_block_visited(pred) + 1 < get_irg_block_visited(current_ir_graph)) { - /* we found a predecessor block at position k that will be removed */ - for (phi = get_irn_link(pred); phi;) { - /* - * the previous phase may already changed the phi, and even - * removed it at all, so check here if this node is still a phi - */ - if (get_irn_op(phi) == op_Phi) { - int q_preds = 0; - - /* move this phi from the predecessor into the block b */ - set_nodes_block(phi, b); - - /* first, copy all 0..k-1 predecessors */ - for (i = 0; i < k; i++) { - pred = get_nodes_block(get_Block_cfgpred(b, i)); - - if (is_Bad(get_Block_cfgpred(b, i))) { - /* Do nothing */ - } else if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { - /* It's an empty block and not yet visited. */ - for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { - /* @@@ Hier brauche ich Schleifeninformation!!! Kontrollflusskante - muss Rueckwaertskante sein! (An allen vier in[q_preds] = phi - Anweisungen.) Trotzdem tuts bisher!! */ - if (! is_Bad(get_Block_cfgpred(pred, j))) - in[q_preds++] = phi; - } - } else { - in[q_preds++] = phi; - } - } - - /* now we are at k, copy the phi predecessors */ - pred = get_nodes_block(get_Block_cfgpred(b, k)); - for (i = 0; i < get_Phi_n_preds(phi); i++) { - if (! is_Bad(get_Block_cfgpred(pred, i))) - in[q_preds++] = get_Phi_pred(phi, i); - } - - /* and now all the rest */ - for (i = k+1; i < get_Block_n_cfgpreds(b); i++) { - pred = get_nodes_block(get_Block_cfgpred(b, i)); - - if (is_Bad(get_Block_cfgpred(b, i))) { - /* Do nothing */ - } else if (get_Block_block_visited(pred) +1 - < get_irg_block_visited(current_ir_graph)) { - /* It's an empty block and not yet visited. */ - for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { - if (! is_Bad(get_Block_cfgpred(pred, j))) - in[q_preds++] = phi; - } - } else { - in[q_preds++] = phi; - } - } - - /* Fix the node */ - if (q_preds == 1) - exchange(phi, in[0]); - else - set_irn_in(phi, q_preds, in); - - assert(q_preds <= max_preds); -// assert(p_preds == q_preds && "Wrong Phi Fix"); - } - phi = get_irn_link(phi); - } - } - } - - /*- Fix the block -*/ - n_preds = 0; - for (i = 0; i < get_Block_n_cfgpreds(b); i++) { - pred = get_nodes_block(get_Block_cfgpred(b, i)); - - if (is_Bad(get_Block_cfgpred(b, i))) { - /* case 1: Do nothing */ - } else if (get_Block_block_visited(pred) +1 - < get_irg_block_visited(current_ir_graph)) { - /* case 2: It's an empty block and not yet visited. */ - assert(get_Block_n_cfgpreds(b) > 1); - /* Else it should be optimized by equivalent_node. */ - for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { - ir_node *pred_block = get_Block_cfgpred(pred, j); - - /* because of breaking loops, not all predecessors are Bad-clean, - * so we must check this here again */ - if (! is_Bad(pred_block)) - in[n_preds++] = pred_block; - } - /* Remove block as it might be kept alive. */ - exchange(pred, b/*new_Bad()*/); - } else { - /* case 3: */ - in[n_preds++] = get_Block_cfgpred(b, i); - } - } - assert(n_preds <= max_preds); - - set_irn_in(b, n_preds, in); - - assert(get_irn_link(b) == NULL || (n_preds == p_preds && "Wrong Phi Fix")); - - xfree(in); +static void optimize_blocks(ir_node *b, void *ctx) { + int i, j, k, n, max_preds, n_preds, p_preds = -1; + ir_node *pred, *phi, *next; + ir_node **in; + merge_env *env = ctx; + + /* Count the number of predecessor if this block is merged with pred blocks + that are empty. */ + max_preds = 0; + for (i = 0, k = get_Block_n_cfgpreds(b); i < k; ++i) { + max_preds += test_whether_dispensable(b, i); + } + in = XMALLOCN(ir_node*, max_preds); + + /*- Fix the Phi nodes of the current block -*/ + for (phi = get_irn_link(b); phi != NULL; phi = next) { + assert(is_Phi(phi)); + next = get_irn_link(phi); + + /* Find the new predecessors for the Phi */ + p_preds = 0; + for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) { + pred = get_Block_cfgpred_block(b, i); + + if (is_Block_dead(pred)) { + /* case Phi 1: Do nothing */ + } else if (is_Block_removable(pred) && !Block_block_visited(pred)) { + /* case Phi 2: It's an empty block and not yet visited. */ + ir_node *phi_pred = get_Phi_pred(phi, i); + + for (j = 0, k = get_Block_n_cfgpreds(pred); j < k; j++) { + /* because of breaking loops, not all predecessors are Bad-clean, + * so we must check this here again */ + if (! is_Bad(get_Block_cfgpred(pred, j))) { + if (get_nodes_block(phi_pred) == pred) { + /* case Phi 2a: */ + assert(is_Phi(phi_pred)); /* Block is empty!! */ + + in[p_preds++] = get_Phi_pred(phi_pred, j); + } else { + /* case Phi 2b: */ + in[p_preds++] = phi_pred; + } + } + } + } else { + /* case Phi 3: */ + in[p_preds++] = get_Phi_pred(phi, i); + } + } + assert(p_preds <= max_preds); + + /* Fix the node */ + if (p_preds == 1) + /* By removal of Bad ins the Phi might be degenerated. */ + exchange(phi, in[0]); + else + set_irn_in(phi, p_preds, in); + env->changed = 1; + } + + /*- This happens only if merge between loop backedge and single loop entry. + Moreover, it is only needed if predb is the direct dominator of b, else there can be no uses + of the Phi's in predb ... -*/ + for (k = 0, n = get_Block_n_cfgpreds(b); k < n; ++k) { + ir_node *predb = get_nodes_block(get_Block_cfgpred(b, k)); + + if (is_Block_removable(predb) && !Block_block_visited(predb)) { + ir_node *next_phi; + + /* we found a predecessor block at position k that will be removed */ + for (phi = get_irn_link(predb); phi; phi = next_phi) { + int q_preds = 0; + next_phi = get_irn_link(phi); + + assert(is_Phi(phi)); + + if (get_Block_idom(b) != predb) { + /* predb is not the dominator. There can't be uses of pred's Phi nodes, kill them .*/ + exchange(phi, new_Bad()); + } else { + /* predb is the direct dominator of b. There might be uses of the Phi nodes from + predb in further block, so move this phi from the predecessor into the block b */ + set_nodes_block(phi, b); + set_irn_link(phi, get_irn_link(b)); + set_irn_link(b, phi); + env->phis_moved = 1; + + /* first, copy all 0..k-1 predecessors */ + for (i = 0; i < k; i++) { + pred = get_Block_cfgpred_block(b, i); + + if (is_Block_dead(pred)) { + /* Do nothing */ + } else if (is_Block_removable(pred) && !Block_block_visited(pred)) { + /* It's an empty block and not yet visited. */ + for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { + if (! is_Bad(get_Block_cfgpred(pred, j))) + in[q_preds++] = phi; + } + } else { + in[q_preds++] = phi; + } + } + + /* now we are at k, copy the phi predecessors */ + pred = get_nodes_block(get_Block_cfgpred(b, k)); + for (i = 0; i < get_Phi_n_preds(phi); i++) { + if (! is_Bad(get_Block_cfgpred(pred, i))) + in[q_preds++] = get_Phi_pred(phi, i); + } + + /* and now all the rest */ + for (i = k+1; i < get_Block_n_cfgpreds(b); i++) { + pred = get_Block_cfgpred_block(b, i); + + if (is_Block_dead(pred)) { + /* Do nothing */ + } else if (is_Block_removable(pred) && !Block_block_visited(pred)) { + /* It's an empty block and not yet visited. */ + for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { + if (! is_Bad(get_Block_cfgpred(pred, j))) + in[q_preds++] = phi; + } + } else { + in[q_preds++] = phi; + } + } + + /* Fix the node */ + if (q_preds == 1) + exchange(phi, in[0]); + else + set_irn_in(phi, q_preds, in); + env->changed = 1; + + assert(q_preds <= max_preds); + // assert(p_preds == q_preds && "Wrong Phi Fix"); + } + } + } + } + + /*- Fix the block -*/ + n_preds = 0; + for (i = 0; i < get_Block_n_cfgpreds(b); i++) { + pred = get_Block_cfgpred_block(b, i); + + if (is_Block_dead(pred)) { + /* case 1: Do nothing */ + } else if (is_Block_removable(pred) && !Block_block_visited(pred)) { + /* case 2: It's an empty block and not yet visited. */ + assert(get_Block_n_cfgpreds(b) > 1 || has_Block_label(b)); + /* Else it should be optimized by equivalent_node. */ + for (j = 0; j < get_Block_n_cfgpreds(pred); j++) { + ir_node *pred_X = get_Block_cfgpred(pred, j); + + /* because of breaking loops, not all predecessors are Bad-clean, + * so we must check this here again */ + if (! is_Bad(pred_X)) + in[n_preds++] = pred_X; + } + /* Remove block as it might be kept alive. */ + exchange(pred, b/*new_Bad()*/); + } else { + /* case 3: */ + in[n_preds++] = get_Block_cfgpred(b, i); + } + } + assert(n_preds <= max_preds); + + set_irn_in(b, n_preds, in); + env->changed = 1; + + assert(get_irn_link(b) == NULL || p_preds == -1 || (n_preds == p_preds && "Wrong Phi Fix")); + xfree(in); +} + +/** + * Block walker: optimize all blocks using the default optimizations. + * This removes Blocks that with only a Jmp predecessor. + */ +static void remove_simple_blocks(ir_node *block, void *ctx) { + ir_node *new_blk = equivalent_node(block); + merge_env *env = ctx; + + if (new_blk != block) { + exchange(block, new_blk); + env->changed = 1; + } } +/** + * Handle pre-optimized table switch Cond's. + * During iropt, all Projs from a switch-Cond are already removed except + * the defProj and maybe the taken one. + * The defProj cannot be removed WITHOUT looking backwards, so we do this here. + * + * @param cond the switch-Cond + * + * @return non-zero if a switch-Cond was optimized + * + * Expects all Proj's linked to the cond node + */ +static int handle_switch_cond(ir_node *cond) { + ir_node *sel = get_Cond_selector(cond); + + ir_node *proj1 = get_irn_link(cond); + ir_node *proj2 = get_irn_link(proj1); + ir_node *jmp, *blk; + + blk = get_nodes_block(cond); + + if (proj2 == NULL) { + /* this Cond has only one Proj: must be the defProj */ + assert(get_Cond_default_proj(cond) == get_Proj_proj(proj1)); + /* convert it into a Jmp */ + jmp = new_r_Jmp(current_ir_graph, blk); + exchange(proj1, jmp); + return 1; + } else if (get_irn_link(proj2) == NULL) { + /* We have two Proj's here. Check if the Cond has + a constant argument */ + tarval *tv = value_of(sel); + + if (tv != tarval_bad) { + /* we have a constant switch */ + long num = get_tarval_long(tv); + long def_num = get_Cond_default_proj(cond); + + if (def_num == get_Proj_proj(proj1)) { + /* first one is the defProj */ + if (num == get_Proj_proj(proj2)) { + jmp = new_r_Jmp(current_ir_graph, blk); + exchange(proj2, jmp); + exchange(proj1, new_Bad()); + return 1; + } + } else if (def_num == get_Proj_proj(proj2)) { + /* second one is the defProj */ + if (num == get_Proj_proj(proj1)) { + jmp = new_r_Jmp(current_ir_graph, blk); + exchange(proj1, jmp); + exchange(proj2, new_Bad()); + return 1; + } + } else { + /* neither: strange, Cond was not optimized so far */ + if (num == get_Proj_proj(proj1)) { + jmp = new_r_Jmp(current_ir_graph, blk); + exchange(proj1, jmp); + exchange(proj2, new_Bad()); + return 1; + } else if (num == get_Proj_proj(proj2)) { + jmp = new_r_Jmp(current_ir_graph, blk); + exchange(proj2, jmp); + exchange(proj1, new_Bad()); + return 1; + } + } + } + } + return 0; +} /* Optimizations of the control flow that also require changes of Phi nodes. * @@ -593,103 +688,188 @@ static void optimize_blocks(ir_node *b, void *env) { * It walks only over block nodes and adapts these and the Phi nodes in these blocks, * which it finds in a linked list computed by the first pass. * - * We use the block_visited flag to mark empty blocks in the first + * We use the mark flag to mark removable blocks in the first * phase. - * @@@ It would be better to add a struct in the link field - * that keeps the Phi list and the mark. Place it on an obstack, as - * we will lose blocks and thereby generate memory leaks. */ void optimize_cf(ir_graph *irg) { - int i, n; - ir_node **in; - ir_node *end = get_irg_end(irg); - ir_graph *rem = current_ir_graph; - irg_dom_state dom_state = get_irg_dom_state(current_ir_graph); - current_ir_graph = irg; - - /* if the graph is not pinned, we cannot determine empty blocks */ - assert(get_irg_pinned(irg) != op_pin_state_floats && - "Control flow optimization need a pinned graph"); - - /* Handle graph state */ - assert(get_irg_phase_state(irg) != phase_building); - set_irg_outs_inconsistent(current_ir_graph); - set_irg_extblk_inconsistent(current_ir_graph); - set_irg_loopinfo_inconsistent(current_ir_graph); - set_irg_doms_inconsistent(current_ir_graph); - - if (dom_state == dom_consistent && get_opt_optimize() && get_opt_unreachable_code()) { - ir_node *end = get_irg_end(irg); - - /* we have dominance info, we can kill dead block */ - irg_block_walk_graph(irg, NULL, remove_dead_block_cf, NULL); - - /* fix the keep-alives */ - for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) { - ir_node *ka = get_End_keepalive(end, i); - - if (is_Block(ka)) { - /* do NOT keep dead blocks */ - if (get_Block_dom_depth(ka) == -1) - set_End_keepalive(end, i, new_Bad()); - } - else if (is_Block_dead(get_nodes_block(ka)) || - get_Block_dom_depth(get_nodes_block(ka)) == -1) - /* do NOT keep nodes in dead blocks */ - set_End_keepalive(end, i, new_Bad()); - } - } - irg_block_walk_graph(current_ir_graph, NULL, remove_senseless_conds, NULL); - - /* Use block visited flag to mark non-empty blocks. */ - inc_irg_block_visited(irg); - irg_walk(end, merge_blocks, collect_nodes, NULL); - - /* Optimize the standard code. */ - irg_block_walk(get_irg_end_block(irg), optimize_blocks, NULL, NULL); - - /* Walk all keep alives, optimize them if block, add to new in-array - for end if useful. */ - in = NEW_ARR_F (ir_node *, 1); - in[0] = get_nodes_block(end); - inc_irg_visited(current_ir_graph); - - /* fix the keep alive */ - for (i = 0, n = get_End_n_keepalives(end); i < n; i++) { - ir_node *ka = get_End_keepalive(end, i); - - if (irn_not_visited(ka)) { - ir_op *op = get_irn_op(ka); - - if ((op == op_Block) && Block_not_block_visited(ka)) { - set_irg_block_visited(current_ir_graph, /* Don't walk all the way to Start. */ - get_irg_block_visited(current_ir_graph)-1); - irg_block_walk(ka, optimize_blocks, NULL, NULL); - mark_irn_visited(ka); - ARR_APP1 (ir_node *, in, ka); - } else if (op == op_Phi) { - mark_irn_visited(ka); - if (! is_Block_dead(get_nodes_block(ka))) - ARR_APP1 (ir_node *, in, ka); - } else if (is_op_keep(op)) { - mark_irn_visited(ka); - if (! is_Block_dead(get_nodes_block(ka))) - ARR_APP1 (ir_node *, in, ka); - } - } - } - DEL_ARR_F(end->in); - end->in = in; - - /* the verifier doesn't work yet with floating nodes */ - if (get_irg_pinned(irg) == op_pin_state_pinned) { - /* after optimize_cf(), only Bad data flow may remain. */ - if (irg_vrfy_bads(irg, BAD_DF | BAD_BLOCK | TUPLE)) { - dump_ir_block_graph(irg, "-vrfy-cf"); - dump_ir_graph(irg, "-vrfy-cf"); - fprintf(stderr, "VRFY_BAD in optimize_cf()\n"); - } - } - - current_ir_graph = rem; + int i, j, n, changed; + ir_node **in = NULL; + ir_node *cond, *end = get_irg_end(irg); + ir_graph *rem = current_ir_graph; + plist_element_t *el; + merge_env env; + + assert(get_irg_phase_state(irg) != phase_building); + + /* if the graph is not pinned, we cannot determine empty blocks */ + assert(get_irg_pinned(irg) != op_pin_state_floats && + "Control flow optimization need a pinned graph"); + + current_ir_graph = irg; + + /* FIXME: control flow opt destroys block edges. So edges are deactivated here. Fix the edges! */ + edges_deactivate(irg); + + /* we use the mark flag to mark removable blocks */ + ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK); +restart: + env.changed = 0; + env.phis_moved = 0; + + /* ALWAYS kill unreachable control flow. Backend cannot handle it anyway. + Use dominator info to kill blocks. Also optimize useless Conds. */ + assure_doms(irg); + irg_block_walk_graph(irg, NULL, remove_unreachable_blocks_and_conds, &env.changed); + + /* fix the keep-alives */ + changed = 0; + for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) { + ir_node *ka = get_End_keepalive(end, i); + + if (is_Block(ka)) { + /* do NOT keep dead blocks */ + if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) { + set_End_keepalive(end, i, new_Bad()); + changed = 1; + } + } else { + ir_node *block = get_nodes_block(ka); + + if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) { + /* do NOT keep nodes in dead blocks */ + set_End_keepalive(end, i, new_Bad()); + changed = 1; + } + } + } + env.changed |= changed; + + ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK); + + env.list = plist_new(); + irg_walk(end, merge_blocks, collect_nodes, &env); + + ir_free_resources(irg, IR_RESOURCE_IRN_LINK); + + if (env.changed) { + /* Handle graph state if was changed. */ + 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); + env.changed = 0; + } + + /* handle all collected switch-Conds */ + foreach_plist(env.list, el) { + cond = plist_element_get_value(el); + env.changed |= handle_switch_cond(cond); + } + plist_free(env.list); + + if (env.changed) { + /* The Cond optimization might generate unreachable code, so restart if + it happens. */ + goto restart; + } + + /* Optimize the standard code. */ + env.changed = 0; + assure_doms(irg); + irg_block_walk_graph(irg, optimize_blocks, remove_simple_blocks, &env); + + /* in rare cases a node may be kept alive more than once, use the visited flag to detect this */ + ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED); + inc_irg_visited(irg); + + /* fix the keep-alives again */ + changed = 0; + for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) { + ir_node *ka = get_End_keepalive(end, i); + + if (is_Block(ka)) { + /* do NOT keep dead blocks */ + if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) { + set_End_keepalive(end, i, new_Bad()); + changed = 1; + } + } else { + ir_node *block = get_nodes_block(ka); + + if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) { + /* do NOT keep nodes in dead blocks */ + set_End_keepalive(end, i, new_Bad()); + changed = 1; + } + } + } + env.changed |= changed; + + remove_End_Bads_and_doublets(end); + + + ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_VISITED); + + if (env.phis_moved) { + /* Bad: when we moved Phi's, we might produce dead Phi nodes + that are kept-alive. + Some other phases cannot copy with this, so will them. + */ + n = get_End_n_keepalives(end); + if (n > 0) { + NEW_ARR_A(ir_node *, in, n); + if (env.changed) { + /* Handle graph state if was changed. */ + set_irg_outs_inconsistent(irg); + } + assure_irg_outs(irg); + + for (i = j = 0; i < n; ++i) { + ir_node *ka = get_End_keepalive(end, i); + + if (is_Phi(ka)) { + int k; + + for (k = get_irn_n_outs(ka) - 1; k >= 0; --k) { + ir_node *user = get_irn_out(ka, k); + + if (user != ka && user != end) { + /* Is it a real user or just a self loop ? */ + break; + } + } + if (k >= 0) + in[j++] = ka; + } else + in[j++] = ka; + } + if (j != n) { + set_End_keepalives(end, j, in); + env.changed = 1; + } + } + } + + if (env.changed) { + /* Handle graph state if was changed. */ + 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); + } + + + /* the verifier doesn't work yet with floating nodes */ + if (get_irg_pinned(irg) == op_pin_state_pinned) { + /* after optimize_cf(), only Bad data flow may remain. */ + if (irg_vrfy_bads(irg, BAD_DF | BAD_BLOCK | TUPLE)) { + dump_ir_block_graph(irg, "-vrfy-cf"); + dump_ir_graph(irg, "-vrfy-cf"); + fprintf(stderr, "VRFY_BAD in optimize_cf()\n"); + } + } + + current_ir_graph = rem; }