X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firlivechk.c;h=bbe8cbbc096823aaca07320d621dbe10ff6ab840;hb=ee7cb73523122ef2cda446d9cbc675edb89acabe;hp=3bdc8dfe4315a8e17ce390a06d7c0ef1d18f90f6;hpb=b933b4f862d3d88376d3e619444518961904ef2f;p=libfirm diff --git a/ir/ana/irlivechk.c b/ir/ana/irlivechk.c index 3bdc8dfe4..bbe8cbbc0 100644 --- a/ir/ana/irlivechk.c +++ b/ir/ana/irlivechk.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 1995-2007 University of Karlsruhe. All right reserved. + * Copyright (C) 1995-2007 Inria Rhone-Alpes. All right reserved. * * This file is part of libFirm. * @@ -37,13 +37,17 @@ * * The precomputation remains valid as long as the CFG is not altered. */ +#include #include #include "irgraph_t.h" +#include "irnode_t.h" #include "irphase_t.h" #include "iredges_t.h" + #include "irprintf.h" +#include "irdom.h" #include "irdump.h" #include "dfs_t.h" @@ -55,45 +59,42 @@ #include "statev.h" typedef struct _bl_info_t { - ir_node *block; /**< The block. */ + const ir_node *block; /**< The block. */ - int id; /**< a tight number for the block. + int be_tgt_calc : 1; + int id : 31; /**< a tight number for the block. we're just reusing the pre num from the DFS. */ - bitset_t *red_reachable; /**< Holds all id's if blocks reachable in the CFG modulo back edges. */ bitset_t *be_tgt_reach; /**< target blocks of back edges whose sources are reachable from this block in the reduced graph. */ - - bitset_t *be_tgt_dom; /**< target blocks of back edges which - are dominated by this block. */ } bl_info_t; #define get_block_info(lv, bl) ((bl_info_t *) phase_get_irn_data(&(lv)->ph, bl)) struct _lv_chk_t { ir_phase ph; - dfs_t *dfs; - DEBUG_ONLY(firm_dbg_module_t *dbg;) + const dfs_t *dfs; int n_blocks; bitset_t *back_edge_src; bitset_t *back_edge_tgt; bl_info_t **map; + DEBUG_ONLY(firm_dbg_module_t *dbg;) }; -static void *init_block_data(ir_phase *ph, ir_node *irn, void *old) +static void *init_block_data(ir_phase *ph, const ir_node *irn, void *old) { lv_chk_t *lv = container_of(ph, lv_chk_t, ph); bl_info_t *bi = phase_alloc(ph, sizeof(bi[0])); - bi->id = dfs_get_pre_num(lv->dfs, irn); + bi->id = get_Block_dom_tree_pre_num(irn); bi->block = irn; bi->red_reachable = bitset_obstack_alloc(phase_obst(ph), lv->n_blocks); bi->be_tgt_reach = bitset_obstack_alloc(phase_obst(ph), lv->n_blocks); - bi->be_tgt_dom = bitset_obstack_alloc(phase_obst(ph), lv->n_blocks); + bi->be_tgt_calc = 0; (void) old; return bi; } @@ -103,12 +104,13 @@ static void *init_block_data(ir_phase *ph, ir_node *irn, void *old) * @param irn A node. * @return 1 if the node shall be considered in liveness, 0 if not. */ -static INLINE int is_liveness_node(const ir_node *irn) +static inline int is_liveness_node(const ir_node *irn) { - switch(get_irn_opcode(irn)) { + switch (get_irn_opcode(irn)) { case iro_Block: case iro_Bad: case iro_End: + case iro_Anchor: return 0; default:; } @@ -130,11 +132,12 @@ static void red_trans_closure(lv_chk_t *lv) int i, n; for (i = 0, n = dfs_get_n_nodes(lv->dfs); i < n; ++i) { - ir_node *bl = dfs_get_post_num_node(lv->dfs, i); + const ir_node *bl = dfs_get_post_num_node(lv->dfs, i); bl_info_t *bi = get_block_info(lv, bl); const ir_edge_t *edge; + bitset_set(bi->red_reachable, bi->id); foreach_block_succ (bl, edge) { ir_node *succ = get_edge_src_irn(edge); bl_info_t *si = get_block_info(lv, succ); @@ -145,10 +148,8 @@ static void red_trans_closure(lv_chk_t *lv) * blocks from there into the reachable set of the current node */ if (kind != DFS_EDGE_BACK) { - assert(dfs_get_post_num(lv->dfs, bl) - > dfs_get_post_num(lv->dfs, succ)); + assert(dfs_get_post_num(lv->dfs, bl) > dfs_get_post_num(lv->dfs, succ)); bitset_or(bi->red_reachable, si->red_reachable); - bitset_set(bi->red_reachable, si->id); } /* mark the block as a back edge src and succ as back edge tgt. */ @@ -162,85 +163,106 @@ static void red_trans_closure(lv_chk_t *lv) } -/** - * Compute the two back edge sets for each block. - * be_tgt_reach contains all target blocks of a back edges reachable from a node. - * be_tgt_dom contains all target blocks of back edges strictly dominated - * by a node. - */ -static void compute_back_edge_sets(lv_chk_t *lv, ir_node *bl) +static void compute_back_edge_chain(lv_chk_t *lv, const ir_node *bl) { - bl_info_t *bi = phase_get_or_set_irn_data(&(lv)->ph, bl); bitset_t *tmp = bitset_alloca(lv->n_blocks); + bl_info_t *bi = get_block_info(lv, bl); bitset_pos_t elm; - ir_node *n; - - dominates_for_each (bl, n) { - bl_info_t *ni = phase_get_or_set_irn_data(&(lv)->ph, n); - - /* compute information for dominance sub tree */ - compute_back_edge_sets(lv, n); - - /* - * of course all blocks dominated by blocks in the - * subtree are also dominated by bl. - */ - bitset_or(bi->be_tgt_dom, ni->be_tgt_dom); - /* - * add the immeditate dominee to the back edge tgt dominance - * bitset if it is the target node of a back edge. - */ - if (bitset_is_set(lv->back_edge_tgt, ni->id)) - bitset_set(bi->be_tgt_dom, ni->id); - } + DBG((lv->dbg, LEVEL_2, "computing T_%d\n", bi->id)); - /* - * iterate over all back edge src nodes which are reachable from - * this nodes and put the targets of the back edges in the be_tgt_reach - * bitset of the node. - */ + /* put all back edge sources reachable (reduced) from here in tmp */ bitset_copy(tmp, bi->red_reachable); bitset_set(tmp, bi->id); bitset_and(tmp, lv->back_edge_src); - bitset_foreach (tmp, elm) { - ir_node *src = lv->map[elm]->block; + bi->be_tgt_calc = 1; + + DBG((lv->dbg, LEVEL_2, "\treachable be src: %B\n", tmp)); + + /* iterate over them ... */ + bitset_foreach(tmp, elm) { + bl_info_t *si = lv->map[elm]; const ir_edge_t *edge; - foreach_block_succ (src, edge) { - ir_node *succ = get_edge_src_irn(edge); - dfs_edge_kind_t kind = dfs_get_edge_kind(lv->dfs, src, succ); + /* and find back edge targets which are not reduced reachable from bl */ + foreach_block_succ (si->block, edge) { + ir_node *tgt = get_edge_src_irn(edge); + bl_info_t *ti = get_block_info(lv, tgt); + dfs_edge_kind_t kind = dfs_get_edge_kind(lv->dfs, si->block, tgt); + + if (kind == DFS_EDGE_BACK && !bitset_is_set(bi->red_reachable, ti->id)) { + if (!ti->be_tgt_calc) + compute_back_edge_chain(lv, tgt); + bitset_set(bi->be_tgt_reach, ti->id); + bitset_or(bi->be_tgt_reach, ti->be_tgt_reach); + } + } + bitset_clear(bi->be_tgt_reach, bi->id); + } +} + + +static inline void compute_back_edge_chains(lv_chk_t *lv) +{ + bitset_pos_t elm; + int i, n; + + DBG((lv->dbg, LEVEL_2, "back edge sources: %B\n", lv->back_edge_src)); + bitset_foreach(lv->back_edge_src, elm) { + compute_back_edge_chain(lv, lv->map[elm]->block); + } + + for (i = 0, n = dfs_get_n_nodes(lv->dfs); i < n; ++i) { + const ir_node *bl = dfs_get_post_num_node(lv->dfs, i); + bl_info_t *bi = get_block_info(lv, bl); - if (kind == DFS_EDGE_BACK) { + const ir_edge_t *edge; + + if (!bitset_is_set(lv->back_edge_tgt, bi->id)) { + foreach_block_succ (bl, edge) { + ir_node *succ = get_edge_src_irn(edge); bl_info_t *si = get_block_info(lv, succ); - bitset_set(bi->be_tgt_reach, si->id); + dfs_edge_kind_t kind = dfs_get_edge_kind(lv->dfs, bl, succ); + + if (kind != DFS_EDGE_BACK) { + assert(dfs_get_post_num(lv->dfs, bl) > dfs_get_post_num(lv->dfs, succ)); + bitset_or(bi->be_tgt_reach, si->be_tgt_reach); + } } } } + + for (i = 0, n = dfs_get_n_nodes(lv->dfs); i < n; ++i) { + const ir_node *bl = dfs_get_post_num_node(lv->dfs, i); + bl_info_t *bi = get_block_info(lv, bl); + bitset_set(bi->be_tgt_reach, bi->id); + } } -lv_chk_t *lv_chk_new(ir_graph *irg) +lv_chk_t *lv_chk_new(ir_graph *irg, const dfs_t *dfs) { - lv_chk_t *res = xmalloc(sizeof(res[0])); + lv_chk_t *res = XMALLOC(lv_chk_t); struct obstack *obst; int i; + edges_deactivate(irg); + edges_activate(irg); + compute_doms(irg); + + stat_ev_tim_push(); phase_init(&res->ph, "liveness check", irg, PHASE_DEFAULT_GROWTH, init_block_data, NULL); obst = phase_obst(&res->ph); FIRM_DBG_REGISTER(res->dbg, "ir.ana.lvchk"); - res->dfs = dfs_new(&absgraph_irg_cfg_succ, irg); + res->dfs = dfs; res->n_blocks = dfs_get_n_nodes(res->dfs); res->back_edge_src = bitset_obstack_alloc(obst, res->n_blocks); res->back_edge_tgt = bitset_obstack_alloc(obst, res->n_blocks); res->map = obstack_alloc(obst, res->n_blocks * sizeof(res->map[0])); + memset(res->map, 0, res->n_blocks * sizeof(res->map[0])); -#ifdef ENABLE_STATS - memset(&res->stat_data, 0, sizeof(res->stat_data)); - res->stat = &res->stat_data; -#endif #if 0 { char name[256]; @@ -256,38 +278,40 @@ lv_chk_t *lv_chk_new(ir_graph *irg) /* fill the map which maps pre_num to block infos */ for (i = res->n_blocks - 1; i >= 0; --i) { - ir_node *irn = dfs_get_pre_num_node(res->dfs, i); - res->map[i] = phase_get_or_set_irn_data(&res->ph, irn); + ir_node *irn = (ir_node *) dfs_get_pre_num_node(res->dfs, i); + bl_info_t *bi = phase_get_or_set_irn_data(&res->ph, irn); + assert(bi->id < res->n_blocks); + assert(res->map[bi->id] == NULL); + res->map[bi->id] = bi; } /* first of all, compute the transitive closure of the CFG *without* back edges */ red_trans_closure(res); - /* now fill the two remaining bitsets concerning back edges */ - compute_back_edge_sets(res, get_irg_start_block(irg)); - - DEBUG_ONLY_NICE { - DBG((res->dbg, LEVEL_1, "liveness chk in %+F\n", irg)); - for (i = res->n_blocks - 1; i >= 0; --i) { - ir_node *irn = dfs_get_pre_num_node(res->dfs, i); - bl_info_t *bi = get_block_info(res, irn); - DBG((res->dbg, LEVEL_1, "lv_chk for %d -> %+F\n", i, irn)); - DBG((res->dbg, LEVEL_1, "\tred reach: %B\n", bi->red_reachable)); - DBG((res->dbg, LEVEL_1, "\ttgt reach: %B\n", bi->be_tgt_reach)); - DBG((res->dbg, LEVEL_1, "\ttgt dom: %B\n", bi->be_tgt_dom)); - } + /* compute back edge chains */ + compute_back_edge_chains(res); + +#ifndef NDEBUG + DBG((res->dbg, LEVEL_1, "liveness chk in %+F\n", irg)); + for (i = res->n_blocks - 1; i >= 0; --i) { + const ir_node *irn = dfs_get_pre_num_node(res->dfs, i); + bl_info_t *bi = get_block_info(res, irn); + DBG((res->dbg, LEVEL_1, "lv_chk for %d -> %+F\n", i, irn)); + DBG((res->dbg, LEVEL_1, "\tred reach: %B\n", bi->red_reachable)); + DBG((res->dbg, LEVEL_1, "\ttgt reach: %B\n", bi->be_tgt_reach)); } +#endif DBG((res->dbg, LEVEL_1, "back edge src: %B\n", res->back_edge_src)); DBG((res->dbg, LEVEL_1, "back edge tgt: %B\n", res->back_edge_tgt)); + stat_ev_tim_pop("lv_chk_cons_time"); return res; } void lv_chk_free(lv_chk_t *lv) { - obstack_free(phase_obst(&lv->ph), NULL); - dfs_free(lv->dfs); + phase_free(&lv->ph); xfree(lv); } @@ -308,24 +332,187 @@ void lv_chk_free(lv_chk_t *lv) * live at the end of the block. * @return 1, if @p what is live at the end at @p bl. */ -unsigned lv_chk_bl_xxx(const lv_chk_t *lv, const ir_node *bl, const ir_node *what) +unsigned lv_chk_bl_in_mask(const lv_chk_t *lv, const ir_node *bl, const ir_node *var) { + ir_node *def_bl; + const ir_edge_t *edge; + stat_ev_cnt_decl(uses); - stat_ev_cnt_decl(iter); + int res = 0; + + assert(is_Block(bl) && "can only check for liveness in a block"); + + if (!is_liveness_node(var)) + return 0; + + def_bl = get_nodes_block(var); + if (def_bl == bl || !block_dominates(def_bl, bl)) { + goto end; + } + + else { + bitset_t *uses = bitset_alloca(lv->n_blocks); + bitset_t *tmp = bitset_alloca(lv->n_blocks); + int min_dom = get_Block_dom_tree_pre_num(def_bl) + 1; + int max_dom = get_Block_dom_max_subtree_pre_num(def_bl); + bl_info_t *bli = get_block_info(lv, bl); + int i; + + DBG((lv->dbg, LEVEL_2, "lv check of %+F, def=%+F,%d != q=%+F,%d\n", + var, def_bl, min_dom - 1, bl, bli->id)); + + foreach_out_edge (var, edge) { + ir_node *user = get_edge_src_irn(edge); + ir_node *use_bl; + bl_info_t *bi; + + if (!is_liveness_node(user)) + continue; + + stat_ev_cnt_inc(uses); + use_bl = get_nodes_block(user); + if (is_Phi(user)) { + int pos = get_edge_src_pos(edge); + use_bl = get_Block_cfgpred_block(use_bl, pos); + } + + if (use_bl == bl) { + res = lv_chk_state_in; + DBG((lv->dbg, LEVEL_2, "\tuse directly in block %+F by %+F\n", use_bl, user)); + goto end; + } + + bi = get_block_info(lv, use_bl); + bitset_set(uses, bi->id); + } + + DBG((lv->dbg, LEVEL_2, "\tuses: %B\n", uses)); + + { + + bitset_copy(tmp, bli->be_tgt_reach); + bitset_set(tmp, bli->id); + + DBG((lv->dbg, LEVEL_2, "\tbe tgt reach: %B, dom span: [%d, %d]\n", tmp, min_dom, max_dom)); + for (i = bitset_next_set(tmp, min_dom); i >= 0 && i <= max_dom; i = bitset_next_set(tmp, i + 1)) { + bl_info_t *ti = lv->map[i]; + DBG((lv->dbg, LEVEL_2, "\tlooking from %d: seeing %B\n", ti->id, ti->red_reachable)); + if (bitset_intersect(ti->red_reachable, uses)) { + res = lv_chk_state_in; + goto end; + } + + bitset_andnot(tmp, ti->red_reachable); + } + } + } + +end: + return res; +} + +unsigned lv_chk_bl_end_mask(const lv_chk_t *lv, const ir_node *bl, const ir_node *var) +{ + ir_node *def_bl; + const ir_edge_t *edge; + + stat_ev_cnt_decl(uses); + + int res = 0; + + assert(is_Block(bl) && "can only check for liveness in a block"); + + if (!is_liveness_node(var)) + return 0; + + def_bl = get_nodes_block(var); + if (!block_dominates(def_bl, bl)) { + goto end; + } else { + bitset_t *uses = bitset_alloca(lv->n_blocks); + bitset_t *tmp = bitset_alloca(lv->n_blocks); + int min_dom = get_Block_dom_tree_pre_num(def_bl) + 1; + int max_dom = get_Block_dom_max_subtree_pre_num(def_bl); + bl_info_t *bli = get_block_info(lv, bl); + int i; + + DBG((lv->dbg, LEVEL_2, "lv end check of %+F, def=%+F,%d != q=%+F,%d\n", + var, def_bl, min_dom - 1, bl, bli->id)); + + foreach_out_edge (var, edge) { + ir_node *user = get_edge_src_irn(edge); + ir_node *use_bl; + bl_info_t *bi; + + if (!is_liveness_node(user)) + continue; + + stat_ev_cnt_inc(uses); + use_bl = get_nodes_block(user); + if (is_Phi(user)) { + int pos = get_edge_src_pos(edge); + use_bl = get_Block_cfgpred_block(use_bl, pos); + + if (bl == use_bl) + res |= lv_chk_state_end; + } + + bi = get_block_info(lv, use_bl); + if (use_bl != bl || bitset_is_set(lv->back_edge_tgt, bi->id)) + bitset_set(uses, bi->id); + } + + DBG((lv->dbg, LEVEL_2, "\tuses: %B\n", uses)); + + bitset_copy(tmp, bli->be_tgt_reach); + bitset_set(tmp, bli->id); + + DBG((lv->dbg, LEVEL_2, "\tbe tgt reach + current: %B, dom span: [%d, %d]\n", tmp, min_dom, max_dom)); + for (i = bitset_next_set(tmp, min_dom); i >= 0 && i <= max_dom; i = bitset_next_set(tmp, i + 1)) { + bl_info_t *ti = lv->map[i]; + DBG((lv->dbg, LEVEL_2, "\tlooking from %d: seeing %B\n", ti->id, ti->red_reachable)); + if (bitset_intersect(ti->red_reachable, uses)) { + res = lv_chk_state_out | lv_chk_state_end; + goto end; + } + + bitset_andnot(tmp, ti->red_reachable); + } + } + +end: + return res; +} + +/** + * Check a nodes liveness situation of a block. + * This routine considers both cases, the live in and end/out case. + * + * @param lv The liveness check environment. + * @param bl The block under investigation. + * @param var The node to check for. + * @return A bitmask of lv_chk_state_XXX fields. + */ +unsigned lv_chk_bl_xxx(const lv_chk_t *lv, const ir_node *bl, const ir_node *var) +{ int res = 0; - ir_node *what_bl; + ir_node *def_bl; + stat_ev_cnt_decl(uses); + stat_ev_cnt_decl(iter); assert(is_Block(bl) && "can only check for liveness in a block"); - if (!is_liveness_node(what)) + /* If the variable ist no liveness related var, bail out. */ + if (!is_liveness_node(var)) return 0; - stat_ev_ctx_push_fobj("node", what); - stat_ev("lv_chk"); + stat_ev_ctx_push_fmt("lv_chk", "%u", get_irn_idx(var)); + stat_ev_tim_push(); - what_bl = get_nodes_block(what); - if (!block_dominates(what_bl, bl)) { + /* If there is no dominance relation, go out, too */ + def_bl = get_nodes_block(var); + if (!block_dominates(def_bl, bl)) { stat_ev("lv_chk_no_dom"); goto end; } @@ -334,12 +521,12 @@ unsigned lv_chk_bl_xxx(const lv_chk_t *lv, const ir_node *bl, const ir_node *wha * If the block in question is the same as the definition block, * the algorithm is simple. Just check for uses not inside this block. */ - if (what_bl == bl) { + if (def_bl == bl) { const ir_edge_t *edge; stat_ev("lv_chk_def_block"); - DBG((lv->dbg, LEVEL_2, "lv check same block %+F in %+F\n", what, bl)); - foreach_out_edge (what, edge) { + DBG((lv->dbg, LEVEL_2, "lv check same block %+F in %+F\n", var, bl)); + foreach_out_edge (var, edge) { ir_node *use = get_edge_src_irn(edge); ir_node *use_bl; @@ -358,7 +545,7 @@ unsigned lv_chk_bl_xxx(const lv_chk_t *lv, const ir_node *bl, const ir_node *wha } } - if (use_bl != what_bl) { + if (use_bl != def_bl) { res = lv_chk_state_end | lv_chk_state_out; goto end; } @@ -367,98 +554,149 @@ unsigned lv_chk_bl_xxx(const lv_chk_t *lv, const ir_node *bl, const ir_node *wha goto end; } - /* this is the complicated case */ + /* + * this is the more complicated case. + * We try to gather as much information as possible during looking + * at the uses. + * + * Note that we know for sure that bl != def_bl. That is sometimes + * silently exploited below. + */ else { - bitset_t *visited = bitset_alloca(lv->n_blocks); - bitset_t *to_visit = bitset_alloca(lv->n_blocks); - bitset_t *next = bitset_alloca(lv->n_blocks); - bitset_t *uses = bitset_alloca(lv->n_blocks); - bl_info_t *def = get_block_info(lv, what_bl); - bl_info_t *bli = get_block_info(lv, bl); + bl_info_t *def = get_block_info(lv, def_bl); + bl_info_t *bli = get_block_info(lv, bl); + bitset_t *uses = bitset_alloca(lv->n_blocks); + bitset_t *Tq; + unsigned i, min_dom, max_dom; const ir_edge_t *edge; - DBG((lv->dbg, LEVEL_2, "lv check different block %+F in %+F\n", what, bl)); - foreach_out_edge (what, edge) { - ir_node *user = get_edge_src_irn(edge); + /* if the block has no DFS info, it cannot be reached. + * This can happen in functions with endless loops. + * we then go out, since nothing is live there. + * + * TODO: Is that right? + */ + if (!bli) + goto end; + + (void) def; + DBG((lv->dbg, LEVEL_2, "lv check %+F (def in %+F #%d) in different block %+F #%d\n", + var, def_bl, def->id, bl, bli->id)); + + foreach_out_edge (var, edge) { + ir_node *user = get_edge_src_irn(edge); + int mask = lv_chk_state_in; + ir_node *use_bl; bl_info_t *bi; + /* if the user is no liveness node, the use does not count */ if (!is_liveness_node(user)) continue; stat_ev_cnt_inc(uses); + + /* if the user is a phi, the use is in the predecessor + * furthermore, prepare a mask so that in the case where + * bl (the block in question) coincides with a use, it + * can be marked live_end there. */ use_bl = get_nodes_block(user); if (is_Phi(user)) { - int pos = get_edge_src_pos(edge); + int pos = get_edge_src_pos(edge); + use_bl = get_Block_cfgpred_block(use_bl, pos); + mask |= lv_chk_state_end; + } - use_bl = get_Block_cfgpred_block(use_bl, pos); - bi = get_block_info(lv, use_bl); - if (use_bl == bl) - res |= lv_chk_state_end | lv_chk_state_in; + /* if the use block coincides with the query block, we + * already gather a little liveness information. + * The variable is surely live there, since bl != def_bl + * (that case is treated above). */ + if (use_bl == bl) + res |= mask; - bitset_set(uses, bi->id); - } + bi = get_block_info(lv, use_bl); - else { - bi = get_block_info(lv, use_bl); + if (bi) bitset_set(uses, bi->id); - if (use_bl == bl) - res |= lv_chk_state_in; - } - } - DBG((lv->dbg, LEVEL_2, "\tuses: %B, #: %d\n", uses, bitset_popcnt(uses))); - bitset_clear(uses, def->id); - bitset_set(to_visit, bli->id); - do { - int id = bitset_next_set(to_visit, 0); - bl_info_t *bi = lv->map[id]; + /* get the dominance range which really matters. all uses outside + * the definition's dominance range are not to consider. note, + * that the definition itself is also not considered. The case + * where bl == def_bl is considered above. */ + min_dom = get_Block_dom_tree_pre_num(def_bl) + 1; + max_dom = get_Block_dom_max_subtree_pre_num(def_bl); + + DBG((lv->dbg, LEVEL_2, "\tuses: %B\n", uses)); + + /* prepare a set with all reachable back edge targets. + * this will determine our "looking points" from where + * we will search/find the calculated uses. */ + Tq = bli->be_tgt_reach; + + /* now, visit all viewing points in the temporary bitset lying + * in the dominance range of the variable. Note that for reducible + * flow-graphs the first iteration is sufficient and the loop + * will be left. */ + DBG((lv->dbg, LEVEL_2, "\tbe tgt reach: %B, dom span: [%d, %d]\n", Tq, min_dom, max_dom)); + i = bitset_next_set(Tq, min_dom); + while(i <= max_dom) { + bl_info_t *ti = lv->map[i]; + int use_in_current_block = bitset_is_set(uses, ti->id); stat_ev_cnt_inc(iter); - DBG((lv->dbg, LEVEL_2, "\tto visit: %B\n", to_visit)); - DBG((lv->dbg, LEVEL_2, "\tvisited: %B\n", visited)); /* - * if one of the blocks is reachable, the node must be live there. - * Note that this is not sufficient, since the nodes reachable - * via back edges are not contained in the red_reachable set. + * This is somewhat tricky. Since this routine handles both, live in + * and end/out we have to handle all the border cases correctly. + * Each node is in its own red_reachable set (see calculation + * function above). That means, that in the case where bl == t, the + * intersection check of uses and reachability below will always + * find an intersection, namely t. + * + * However, if a block contains a use and the variable is dead + * afterwards, it is not live end/out at that block. Besides + * back-edge target. If a var is live-in at a back-edge target it + * is also live out/end there since the variable is live in the + * underlying loop. So in the case where t == bl and that is not + * a back-edge target, we have to remove that use from consideration + * to determine if the var is live out/end there. + * + * Note that the live in information has been calculated by the + * uses iteration above. */ - if (bitset_intersect(bi->red_reachable, uses)) { - res = lv_chk_state_end | lv_chk_state_out | lv_chk_state_in; + if (ti == bli && !bitset_is_set(lv->back_edge_tgt, ti->id)) { + DBG((lv->dbg, LEVEL_2, "\tlooking not from a back edge target and q == t. removing use: %d\n", ti->id)); + bitset_clear(uses, ti->id); + } + + /* If we can reach a use, the variable is live there and we say goodbye */ + DBG((lv->dbg, LEVEL_2, "\tlooking from %d: seeing %B\n", ti->id, ti->red_reachable)); + if (bitset_intersect(ti->red_reachable, uses)) { + res |= lv_chk_state_in | lv_chk_state_out | lv_chk_state_end; goto end; } /* - * if not, we have to check the back edges in question, if - * they lead to places which are reachable. + * if we deleted a use do to the commentary above, we have to + * re-add it since it might be visible from further view points + * (we only need that in the non-reducible case). */ - else { - bitset_set(visited, id); - bitset_or(visited, bi->red_reachable); + if (use_in_current_block) + bitset_set(uses, ti->id); - bitset_copy(next, bi->be_tgt_reach); - bitset_and(next, def->be_tgt_dom); - DBG((lv->dbg, LEVEL_2, "\tnext: %B\n----\n", next)); - - if (bitset_intersect(uses, next)) { - res = lv_chk_state_end | lv_chk_state_out | lv_chk_state_in; - goto end; - } - - bitset_or(to_visit, next); - bitset_andnot(to_visit, visited); + i = bitset_next_set(Tq, get_Block_dom_max_subtree_pre_num(ti->block) + 1); + } - } - } while (!bitset_is_empty(to_visit)); } end: + stat_ev_tim_pop("lv_chk_query_time"); stat_ev_cnt_done(uses, "lv_chk_uses"); stat_ev_cnt_done(iter, "lv_chk_iter"); - stat_ev_ctx_pop(); + stat_ev_ctx_pop("lv_chk"); return res; }