X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=ir%2Fopt%2Fcfopt.c;h=e0cd1ac0d2af073bf36fef445f6955b921ea71b0;hb=c0bef4f5aded93790e8d181ec3fcdcd6429a3cd3;hp=b91b61e4a6b7d2ff2d36e70bf303e6d8658d77c3;hpb=362c133139e49392bafd15a511c02786b5f7c1a0;p=libfirm diff --git a/ir/opt/cfopt.c b/ir/opt/cfopt.c index b91b61e4a..e0cd1ac0d 100644 --- a/ir/opt/cfopt.c +++ b/ir/opt/cfopt.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved. + * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved. * * This file is part of libFirm. * @@ -27,6 +27,8 @@ # include "config.h" #endif +#include "iroptimize.h" + #include #include "plist.h" @@ -51,7 +53,6 @@ #include "irflag_t.h" #include "firmstat.h" -#include "cfopt.h" #include "iropt_dbg.h" /*------------------------------------------------------------------*/ @@ -61,8 +62,14 @@ /* 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. @@ -80,11 +87,10 @@ * 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) { +static int remove_senseless_conds(ir_node *bl) { int i, j; int n = get_Block_n_cfgpreds(bl); - - assert(is_Block(bl)); + int changed = 0; for (i = 0; i < n; ++i) { ir_node *pred_i = get_Block_cfgpred(bl, i); @@ -103,13 +109,22 @@ static void remove_senseless_conds(ir_node *bl, void *data) { 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. * Optimizes blocks with equivalent_node(). This is tricky, @@ -117,27 +132,31 @@ 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 *node, void *env) { - int i, n; +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 */ - - /* 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()) { - for (i = 0, n = get_Block_n_cfgpreds(node); i < n; ++i) - set_Block_cfgpred(node, i, skip_Tuple(get_Block_cfgpred(node, i))); + 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)) + 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! */ @@ -154,7 +173,8 @@ static void merge_blocks(ir_node *node, void *env) { assert((get_opt_control_flow_straightening() || get_opt_control_flow_weak_simplification()) && ("strange flag setting")); - exchange (b, new_block); + exchange(b, new_block); + env->changed = 1; b = new_block; new_block = equivalent_node(b); } @@ -162,70 +182,89 @@ static void merge_blocks(ir_node *node, void *env) { /* 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)) + 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) { +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 */ + /* 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 *pred_X = get_Block_cfgpred(block, i); + ir_node *skipped = skip_Tuple(pred_X); - if (! is_Bad(pred_X)) { - ir_node *pred_bl = get_nodes_block(skip_Proj(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 blocks */ + set_Block_removable(block); } /** * Collects all Phi nodes in link list of Block. - * Marks all blocks "block_visited" if they contain a node other + * 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) { - ir_op *op = get_irn_op(n); - plist_t *list = env; - - if (op != op_Block) { - ir_node *b = get_nodes_block(n); - - if (op == op_Phi) { +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 (op != op_Jmp && !is_Bad(b)) { /* Check for non empty block. */ - mark_Block_block_visited(b); + } else if (code != iro_Jmp && !is_Bad(b)) { /* Check for non-empty block. */ + set_Block_non_removable(b); - if (op == op_Proj) { /* link Proj nodes */ + 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 (op == op_Cond) { + } 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(list, n); + plist_insert_back(env->list, n); } } } @@ -234,11 +273,12 @@ static void collect_nodes(ir_node *n, void *env) { /** Returns true if pred is predecessor of block. */ static int is_pred_of(ir_node *pred, ir_node *b) { - int i, n; + int i; - for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++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; + if (b_pred == pred) + return 1; } return 0; } @@ -278,17 +318,15 @@ static int test_whether_dispensable(ir_node *b, int pos) { if (is_Block_dead(pred)) return 0; - if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { - + 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_block_visited(pred, get_irg_block_visited(current_ir_graph)-1); + set_Block_non_removable(pred); return 1; } /* Seems to be empty. At least we detected this in collect_nodes. */ - if (!get_irn_link(b)) { + if (get_irn_link(b) == NULL) { /* There are no Phi nodes ==> all predecessors are dispensable. */ n_preds = get_Block_n_cfgpreds(pred); } else { @@ -296,10 +334,8 @@ static int test_whether_dispensable(ir_node *b, int pos) { 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++) { + 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; @@ -322,18 +358,10 @@ static int test_whether_dispensable(ir_node *b, int pos) { return n_preds; non_dispensable: - set_Block_block_visited(pred, get_irg_block_visited(current_ir_graph)-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. @@ -381,11 +409,11 @@ 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) { +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; ir_node **in; - defer_ex_phi *defers; + merge_env *env = ctx; /* Count the number of predecessor if this block is merged with pred blocks that are empty. */ @@ -395,21 +423,6 @@ static void optimize_blocks(ir_node *b, void *env) { } 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); @@ -419,11 +432,9 @@ static void optimize_blocks(ir_node *b, void *env) { 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))) { + if (is_Block_dead(pred)) { /* case Phi 1: Do nothing */ - } - else if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { + } 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); @@ -442,38 +453,6 @@ static void optimize_blocks(ir_node *b, void *env) { } } } - - /* 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); @@ -487,47 +466,47 @@ static void optimize_blocks(ir_node *b, void *env) { exchange(phi, in[0]); else set_irn_in(phi, p_preds, in); + env->changed = 1; 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. -*/ + 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) { - pred = get_nodes_block(get_Block_cfgpred(b, 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; - 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 */ + 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_Bad(pred)) { + if (is_Block_dead(pred)) { /* Do nothing */ - } else if (get_Block_block_visited(pred) + 1 - < get_irg_block_visited(current_ir_graph)) { + } 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++) { - /* @@@ 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; } @@ -545,12 +524,11 @@ static void optimize_blocks(ir_node *b, void *env) { /* 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)); + pred = get_Block_cfgpred_block(b, i); - if (is_Bad(get_Block_cfgpred(b, i))) { + if (is_Block_dead(pred)) { /* Do nothing */ - } else if (get_Block_block_visited(pred) +1 - < get_irg_block_visited(current_ir_graph)) { + } 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))) @@ -566,11 +544,11 @@ static void optimize_blocks(ir_node *b, void *env) { 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"); } - phi = get_irn_link(phi); } } } @@ -580,20 +558,19 @@ static void optimize_blocks(ir_node *b, void *env) { for (i = 0; i < get_Block_n_cfgpreds(b); i++) { pred = get_Block_cfgpred_block(b, i); - if (is_Bad(pred)) { + if (is_Block_dead(pred)) { /* case 1: Do nothing */ - } else if (get_Block_block_visited(pred) +1 - < get_irg_block_visited(current_ir_graph)) { + } 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); /* 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); + 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_block)) - in[n_preds++] = pred_block; + if (! is_Bad(pred_X)) + in[n_preds++] = pred_X; } /* Remove block as it might be kept alive. */ exchange(pred, b/*new_Bad()*/); @@ -605,19 +582,24 @@ static void optimize_blocks(ir_node *b, void *env) { assert(n_preds <= max_preds); set_irn_in(b, n_preds, in); + env->changed = 1; - assert(get_irn_link(b) == NULL || (n_preds == p_preds && "Wrong Phi Fix")); + assert(get_irn_link(b) == NULL || p_preds == -1 || (n_preds == p_preds && "Wrong Phi Fix")); xfree(in); } /** - * Walker: optimize all blocks using the default optimizations. + * 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 *env) { +static void remove_simple_blocks(ir_node *block, void *ctx) { ir_node *new_blk = equivalent_node(block); - if (new_blk != block) + merge_env *env = ctx; + + if (new_blk != block) { exchange(block, new_blk); + env->changed = 1; + } } /** @@ -706,20 +688,16 @@ static int handle_switch_cond(ir_node *cond) { * 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, j, n; ir_node **in = NULL; ir_node *cond, *end = get_irg_end(irg); ir_graph *rem = current_ir_graph; - irg_dom_state dom_state = get_irg_dom_state(current_ir_graph); - plist_t *list; plist_element_t *el; + merge_env env; assert(get_irg_phase_state(irg) != phase_building); @@ -729,59 +707,81 @@ void optimize_cf(ir_graph *irg) { current_ir_graph = irg; + /* FIXME: control flow opt destroys block edges. So edges are deactivated here. Fix the edges! */ edges_deactivate(irg); - /* Handle graph state */ - 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; - - /* we have dominance info, we can kill dead block */ - irg_block_walk_graph(irg, NULL, remove_dead_block_cf, NULL); - - /* fix the keep-alives */ - end = get_irg_end(irg); - 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) < 0) - set_End_keepalive(end, i, new_Bad()); - } else if (is_Block_dead(get_nodes_block(ka)) || - get_Block_dom_depth(get_nodes_block(ka)) < 0) - /* do NOT keep nodes in dead blocks */ + /* 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 */ + 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()); + env.changed = 1; + } + } else if (is_Block_dead(get_nodes_block(ka)) || + get_Block_dom_depth(get_nodes_block(ka)) < 0) { + /* do NOT keep nodes in dead blocks */ + set_End_keepalive(end, i, new_Bad()); + env.changed = 1; } } - irg_block_walk_graph(irg, NULL, remove_senseless_conds, NULL); - /* Use block visited flag to mark non-empty blocks. */ - inc_irg_block_visited(irg); + ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK); - list = plist_new(); - irg_walk(end, merge_blocks, collect_nodes, list); + 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); + env.changed = 0; + } /* handle all collected switch-Conds */ - foreach_plist(list, el) { + foreach_plist(env.list, el) { cond = plist_element_get_value(el); - handle_switch_cond(cond); + 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; } - plist_free(list); /* Optimize the standard code. */ - irg_block_walk(get_irg_end_block(irg), optimize_blocks, remove_simple_blocks, NULL); + env.changed = 0; + assure_doms(irg); + irg_block_walk(get_irg_end_block(irg), optimize_blocks, remove_simple_blocks, &env); /* Walk all keep alives, optimize them if block, add to new in-array for end if useful. */ n = get_End_n_keepalives(end); if (n > 0) NEW_ARR_A(ir_node *, in, n); + + /* in rare cases a node may be kept alive more than once, use the visited flag to detect this */ inc_irg_visited(irg); + ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED); /* fix the keep alive */ for (i = j = 0; i < n; i++) { @@ -790,25 +790,76 @@ void optimize_cf(ir_graph *irg) { 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(irg, /* Don't walk all the way to Start. */ - get_irg_block_visited(irg)-1); - irg_block_walk(ka, optimize_blocks, remove_simple_blocks, NULL); + if ((op == op_Block) && !Block_block_visited(ka)) { + /* irg_block_walk() will increase the block visited flag, but we must visit only + these blocks that are not visited yet, so decrease it first. */ + set_irg_block_visited(irg, get_irg_block_visited(irg) - 1); + irg_block_walk(ka, optimize_blocks, remove_simple_blocks, &env.changed); mark_irn_visited(ka); in[j++] = ka; - } else if (op == op_Phi) { - mark_irn_visited(ka); - if (! is_Block_dead(get_nodes_block(ka))) - in[j++] = ka; - } else if (is_op_keep(op)) { + } else { mark_irn_visited(ka); + /* don't keep alive dead blocks */ if (! is_Block_dead(get_nodes_block(ka))) in[j++] = ka; } } } - if (j != n) + if (j != n) { set_End_keepalives(end, j, in); + env.changed = 1; + } + + 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) { + 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); + } + + /* 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. */