X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fldstopt.c;h=2e9aeeab0e5e56476b30a94263b25ee65fdeb69d;hb=ee5c07444d26eaae35ff78a7b2a7605ad3dc3f2b;hp=86a34c233231cc5cc8accbedb9ef28b6ec3aae50;hpb=d6a329898caaf412be1561a8345c7aeccc5f5a5a;p=libfirm diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c index 86a34c233..2e9aeeab0 100644 --- a/ir/opt/ldstopt.c +++ b/ir/opt/ldstopt.c @@ -8,6 +8,20 @@ * Copyright: (c) 1998-2004 Universität Karlsruhe * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE. */ +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#ifdef HAVE_ALLOCA_H +#include +#endif +#ifdef HAVE_MALLOC_H +#include +#endif +#ifdef HAVE_STRING_H +# include +#endif + # include "irnode_t.h" # include "irgraph_t.h" # include "irmode_t.h" @@ -21,42 +35,76 @@ # include "iropt_dbg.h" # include "irflag_t.h" # include "array.h" -# include "firmstat.h" +# include "irhooks.h" +# include "irtools.h" +# include "opt_polymorphy.h" + +#ifdef DO_CACHEOPT +#include "cacheopt/cachesim.h" +#endif #undef IMAX #define IMAX(a,b) ((a) > (b) ? (a) : (b)) #define MAX_PROJ IMAX(pn_Load_max, pn_Store_max) +enum changes_t { + DF_CHANGED = 1, /**< data flow changed */ + CF_CHANGED = 2, /**< control flow changed */ +}; + /** * walker environment */ typedef struct _walk_env_t { struct obstack obst; /**< list of all stores */ - int changes; + unsigned changes; /**< a bitmask of graph changes */ } walk_env_t; +/** + * flags for Load/Store + */ +enum ldst_flags_t { + LDST_VISITED = 1 /**< if set, this Load/Store is already visited */ +}; + /** * a Load/Store info */ typedef struct _ldst_info_t { - ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */ - ir_node *exc_block; /**< the exception block if available */ - int exc_idx; /**< predecessor index in the exception block */ + ir_node *projs[MAX_PROJ]; /**< list of Proj's of this node */ + ir_node *exc_block; /**< the exception block if available */ + int exc_idx; /**< predecessor index in the exception block */ + unsigned flags; /**< flags */ + unsigned visited; /**< visited counter for breaking loops */ } ldst_info_t; /** - * walker, clears all links first + * flags for control flow */ -static void init_links(ir_node *n, void *env) -{ - set_irn_link(n, NULL); -} +enum block_flags_t { + BLOCK_HAS_COND = 1, /**< Block has conditional control flow */ + BLOCK_HAS_EXC = 2 /**< Block has exceptional control flow */ +}; + +/** + * a Block info + */ +typedef struct _block_info_t { + unsigned flags; /**< flags for the block */ +} block_info_t; + +/** the master visited flag for loop detection. */ +static unsigned master_visited = 0; + +#define INC_MASTER() ++master_visited +#define MARK_NODE(info) (info)->visited = master_visited +#define NODE_VISITED(info) (info)->visited >= master_visited /** * get the Load/Store info of a node */ -static ldst_info_t *get_info(ir_node *node, walk_env_t *env) +static ldst_info_t *get_ldst_info(ir_node *node, walk_env_t *env) { ldst_info_t *info = get_irn_link(node); @@ -70,10 +118,27 @@ static ldst_info_t *get_info(ir_node *node, walk_env_t *env) return info; } +/** + * get the Block info of a node + */ +static block_info_t *get_block_info(ir_node *node, walk_env_t *env) +{ + block_info_t *info = get_irn_link(node); + + if (! info) { + info = obstack_alloc(&env->obst, sizeof(*info)); + + memset(info, 0, sizeof(*info)); + + set_irn_link(node, info); + } + return info; +} + /** * update the projection info for a Load/Store */ -static int update_projs(ldst_info_t *info, ir_node *proj) +static unsigned update_projs(ldst_info_t *info, ir_node *proj) { long nr = get_Proj_proj(proj); @@ -82,7 +147,7 @@ static int update_projs(ldst_info_t *info, ir_node *proj) if (info->projs[nr]) { /* there is already one, do CSE */ exchange(proj, info->projs[nr]); - return 1; + return DF_CHANGED; } else { info->projs[nr] = proj; @@ -91,9 +156,13 @@ static int update_projs(ldst_info_t *info, ir_node *proj) } /** - * update the exception block info for a Load/Store + * update the exception block info for a Load/Store node. + * + * @param info the load/store info struct + * @param block the exception handler block for this load/store + * @param pos the control flow input of the block */ -static int update_exc(ldst_info_t *info, ir_node *block, int pos) +static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos) { assert(info->exc_block == NULL && "more than one exception block found"); @@ -102,122 +171,515 @@ static int update_exc(ldst_info_t *info, ir_node *block, int pos) return 0; } +#define get_irn_out_n(node) (unsigned)PTR_TO_INT(get_irn_link(node)) +#define set_irn_out_n(node, n) set_irn_link(adr, INT_TO_PTR(n)) + /** * walker, collects all Load/Store/Proj nodes + * + * walks from Start -> End */ static void collect_nodes(ir_node *node, void *env) { - ir_node *pred; - ldst_info_t *info; + ir_op *op = get_irn_op(node); + ir_node *pred, *blk, *pred_blk; + ldst_info_t *ldst_info; walk_env_t *wenv = env; - if (get_irn_op(node) == op_Proj) { + if (op == op_Proj) { + ir_node *adr; + ir_op *op; + pred = get_Proj_pred(node); + op = get_irn_op(pred); + + if (op == op_Load) { + ldst_info = get_ldst_info(pred, wenv); - if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) { - info = get_info(pred, wenv); + wenv->changes |= update_projs(ldst_info, node); - wenv->changes |= update_projs(info, node); + if ((ldst_info->flags & LDST_VISITED) == 0) { + adr = get_Load_ptr(pred); + set_irn_out_n(adr, get_irn_out_n(adr) + 1); + + ldst_info->flags |= LDST_VISITED; + } + + /* + * Place the Proj's to the same block as the + * predecessor Load. This is always ok and prevents + * "non-SSA" form after optimizations if the Proj + * is in a wrong block. + */ + blk = get_nodes_block(node); + pred_blk = get_nodes_block(pred); + if (blk != pred_blk) { + wenv->changes |= DF_CHANGED; + set_nodes_block(node, pred_blk); + } + } + else if (op == op_Store) { + ldst_info = get_ldst_info(pred, wenv); + + wenv->changes |= update_projs(ldst_info, node); + + if ((ldst_info->flags & LDST_VISITED) == 0) { + adr = get_Store_ptr(pred); + set_irn_out_n(adr, get_irn_out_n(adr) + 1); + + ldst_info->flags |= LDST_VISITED; + } + + /* + * Place the Proj's to the same block as the + * predecessor Store. This is always ok and prevents + * "non-SSA" form after optimizations if the Proj + * is in a wrong block. + */ + blk = get_nodes_block(node); + pred_blk = get_nodes_block(pred); + if (blk != pred_blk) { + wenv->changes |= DF_CHANGED; + set_nodes_block(node, pred_blk); + } } } - else if (get_irn_op(node) == op_Block) { /* check, if it's an exception block */ - int i, n; + else if (op == op_Block) { /* check, if it's an exception block */ + int i; + + for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) { + ir_node *pred_block; + block_info_t *bl_info; - for (i = 0, n = get_Block_n_cfgpreds(node); i < n; ++i) { pred = skip_Proj(get_Block_cfgpred(node, i)); + /* ignore Bad predecessors, they will be removed later */ + if (is_Bad(pred)) + continue; + + pred_block = get_nodes_block(pred); + bl_info = get_block_info(pred_block, wenv); + + if (is_fragile_op(pred)) + bl_info->flags |= BLOCK_HAS_EXC; + else if (is_irn_forking(pred)) + bl_info->flags |= BLOCK_HAS_COND; + if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) { - info = get_info(pred, wenv); + ldst_info = get_ldst_info(pred, wenv); + + wenv->changes |= update_exc(ldst_info, node, i); + } + } + } +} + +/** + * Returns an entity if the address ptr points to a constant one. + */ +static entity *find_constant_entity(ir_node *ptr) +{ + for (;;) { + ir_op *op = get_irn_op(ptr); - wenv->changes |= update_exc(info, node, i); + if (op == op_SymConst && (get_SymConst_kind(ptr) == symconst_addr_ent)) { + return get_SymConst_entity(ptr); + } + else if (op == op_Sel) { + entity *ent = get_Sel_entity(ptr); + ir_type *tp = get_entity_owner(ent); + + /* Do not fiddle with polymorphism. */ + if (is_Class_type(get_entity_owner(ent)) && + ((get_entity_n_overwrites(ent) != 0) || + (get_entity_n_overwrittenby(ent) != 0) ) ) + return NULL; + + if (variability_constant == get_entity_variability(ent)) + return ent; + + if (is_Array_type(tp)) { + /* check bounds */ + int i, n; + + for (i = 0, n = get_Sel_n_indexs(ptr); i < n; ++i) { + ir_node *bound; + tarval *tlower, *tupper; + ir_node *index = get_Sel_index(ptr, i); + tarval *tv = computed_value(index); + + /* check if the index is constant */ + if (tv == tarval_bad) + return NULL; + + bound = get_array_lower_bound(tp, i); + tlower = computed_value(bound); + bound = get_array_upper_bound(tp, i); + tupper = computed_value(bound); + + if (tlower == tarval_bad || tupper == tarval_bad) + return NULL; + + if (tarval_cmp(tv, tlower) & pn_Cmp_Lt) + return NULL; + if (tarval_cmp(tupper, tv) & pn_Cmp_Lt) + return NULL; + + /* ok, bounds check finished */ + } } + + /* try next */ + ptr = get_Sel_ptr(ptr); } + else + return NULL; } } +/** + * Return the Selection index of a Sel node from dimension n + */ +static long get_Sel_array_index_long(ir_node *n, int dim) { + ir_node *index = get_Sel_index(n, dim); + assert(get_irn_op(index) == op_Const); + return get_tarval_long(get_Const_tarval(index)); +} + +/** + * Returns the accessed component graph path for an + * node computing an address. + * + * @param ptr the node computing the address + * @param depth current depth in steps upward from the root + * of the address + */ +static compound_graph_path *rec_get_accessed_path(ir_node *ptr, int depth) { + compound_graph_path *res = NULL; + entity *root, *field; + int path_len, pos; + + if (get_irn_op(ptr) == op_SymConst) { + /* a SymConst. If the depth is 0, this is an access to a global + * entity and we don't need a component path, else we know + * at least it's length. + */ + assert(get_SymConst_kind(ptr) == symconst_addr_ent); + root = get_SymConst_entity(ptr); + res = (depth == 0) ? NULL : new_compound_graph_path(get_entity_type(root), depth); + } + else { + assert(get_irn_op(ptr) == op_Sel); + /* it's a Sel, go up until we find the root */ + res = rec_get_accessed_path(get_Sel_ptr(ptr), depth+1); + + /* fill up the step in the path at the current position */ + field = get_Sel_entity(ptr); + path_len = get_compound_graph_path_length(res); + pos = path_len - depth - 1; + set_compound_graph_path_node(res, pos, field); + + if (is_Array_type(get_entity_owner(field))) { + assert(get_Sel_n_indexs(ptr) == 1 && "multi dim arrays not implemented"); + set_compound_graph_path_array_index(res, pos, get_Sel_array_index_long(ptr, 0)); + } + } + return res; +} + +/** Returns an access path or NULL. The access path is only + * valid, if the graph is in phase_high and _no_ address computation is used. + */ +static compound_graph_path *get_accessed_path(ir_node *ptr) { + return rec_get_accessed_path(ptr, 0); +} + /** * optimize a Load */ -static int optimize_load(ir_node *load) +static unsigned optimize_load(ir_node *load) { ldst_info_t *info = get_irn_link(load); ir_mode *load_mode = get_Load_mode(load); - ir_node *pred, *mem, *ptr; - int res = 1; + ir_node *pred, *mem, *ptr, *new_node; + entity *ent; + unsigned res = 0; + /* do NOT touch volatile loads for now */ if (get_Load_volatility(load) == volatility_is_volatile) return 0; + /* the address of the load to be optimized */ + ptr = get_Load_ptr(load); + /* - * BEWARE: one might think that checking the modes is useless, because - * if the pointers are identical, they refer to the same object. - * This is only true in strong typed languages, not is C were the following - * is possible a = *(type1 *)p; b = *(type2 *)p ... + * Check if we can remove the exception from a Load: + * This can be done, if the address is from an Sel(Alloc) and + * the Sel type is a subtype of the allocated type. + * + * This optimizes some often used OO constructs, + * like x = new O; x->t; */ + if (info->projs[pn_Load_X_except]) { + if (is_Sel(ptr)) { + ir_node *mem = get_Sel_mem(ptr); + + if (get_irn_op(skip_Proj(mem)) == op_Alloc) { + /* ok, check the types */ + entity *ent = get_Sel_entity(ptr); + ir_type *s_type = get_entity_type(ent); + ir_type *a_type = get_Alloc_type(mem); + + if (is_SubClass_of(s_type, a_type)) { + /* ok, condition met: there can't be an exception because + * Alloc guarantees that enough memory was allocated */ + + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + res |= CF_CHANGED; + } + } + } + else if ((get_irn_op(skip_Proj(ptr)) == op_Alloc) || + ((get_irn_op(ptr) == op_Cast) && (get_irn_op(skip_Proj(get_Cast_op(ptr))) == op_Alloc))) { + /* simple case: a direct load after an Alloc. Firm Alloc throw + * an exception in case of out-of-memory. So, there is no way for an + * exception in this load. + * This code is constructed by the "exception lowering" in the Jack compiler. + */ + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + res |= CF_CHANGED; + } + } - ptr = get_Load_ptr(load); + /* the mem of the Load. Must still be returned after optimization */ mem = get_Load_mem(load); - pred = skip_Proj(mem); if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) { /* a Load which value is neither used nor exception checked, remove it */ exchange(info->projs[pn_Load_M], mem); - res = 1; + + return res | DF_CHANGED; } - else if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && - get_irn_mode(get_Store_value(pred)) == load_mode) { - /* - * a load immediately after a store -- a read after write. - * We may remove the Load, if it does not have an exception handler - * OR they are in the same block. In the latter case the Load cannot - * throw an exception when the previous Store was quiet. - */ - if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { - exchange( info->projs[pn_Load_res], get_Store_value(pred) ); - if (info->projs[pn_Load_M]) - exchange(info->projs[pn_Load_M], mem); - - /* no exception */ - if (info->projs[pn_Load_X_except]) - exchange( info->projs[pn_Load_X_except], new_Bad()); - res = 1; + + /* Load from a constant polymorphic field, where we can resolve + polymorphism. */ + new_node = transform_node_Load(load); + if (new_node != load) { + if (info->projs[pn_Load_M]) { + exchange(info->projs[pn_Load_M], mem); + info->projs[pn_Load_M] = NULL; + } + if (info->projs[pn_Load_X_except]) { + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; } + if (info->projs[pn_Load_res]) + exchange(info->projs[pn_Load_res], new_node); + return res | DF_CHANGED; } - else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && - get_Load_mode(pred) == load_mode) { + + /* check if we can determine the entity that will be loaded */ + ent = find_constant_entity(ptr); + if (ent) { + if ((allocation_static == get_entity_allocation(ent)) && + (visibility_external_allocated != get_entity_visibility(ent))) { + /* a static allocation that is not external: there should be NO exception + * when loading. */ + + /* no exception, clear the info field as it might be checked later again */ + if (info->projs[pn_Load_X_except]) { + exchange(info->projs[pn_Load_X_except], new_Bad()); + info->projs[pn_Load_X_except] = NULL; + res |= CF_CHANGED; + } + + if (variability_constant == get_entity_variability(ent) + && is_atomic_entity(ent)) { + /* Might not be atomic after + lowering of Sels. In this + case we could also load, but + it's more complicated. */ + /* more simpler case: we load the content of a constant value: + * replace it by the constant itself + */ + + /* no memory */ + if (info->projs[pn_Load_M]) { + exchange(info->projs[pn_Load_M], mem); + res |= DF_CHANGED; + } + + /* no result :-) */ + if (info->projs[pn_Load_res]) { + if (is_atomic_entity(ent)) { + ir_node *c = copy_const_value(get_irn_dbg_info(load), get_atomic_ent_value(ent)); + + DBG_OPT_RC(load, c); + exchange(info->projs[pn_Load_res], c); + return DF_CHANGED | res; + } + } + } + else if (variability_constant == get_entity_variability(ent)) { + compound_graph_path *path = get_accessed_path(ptr); + + if (path) { + ir_node *c; + + assert(is_proper_compound_graph_path(path, get_compound_graph_path_length(path)-1)); + /* + { + int j; + for (j = 0; j < get_compound_graph_path_length(path); ++j) { + entity *node = get_compound_graph_path_node(path, j); + fprintf(stdout, ".%s", get_entity_name(node)); + if (is_Array_type(get_entity_owner(node))) + fprintf(stdout, "[%d]", get_compound_graph_path_array_index(path, j)); + } + printf("\n"); + } + */ + + c = get_compound_ent_value_by_path(ent, path); + free_compound_graph_path(path); + + /* printf(" cons: "); DDMN(c); */ + + if (info->projs[pn_Load_M]) { + exchange(info->projs[pn_Load_M], mem); + res |= DF_CHANGED; + } + if (info->projs[pn_Load_res]) { + exchange(info->projs[pn_Load_res], copy_const_value(get_irn_dbg_info(load), c)); + return res | DF_CHANGED; + } + } + else { + /* We can not determine a correct access path. E.g., in jack, we load + a byte from an object to generate an exception. Happens in test program + Reflectiontest. + printf(">>>>>>>>>>>>> Found access to constant entity %s in function %s\n", get_entity_name(ent), + get_entity_name(get_irg_entity(current_ir_graph))); + printf(" load: "); DDMN(load); + printf(" ptr: "); DDMN(ptr); + */ + } + } + } + } + + /* Check, if the address of this load is used more than once. + * If not, this load cannot be removed in any case. */ + if (get_irn_out_n(ptr) <= 1) + return res; + + /* + * follow the memory chain as long as there are only Loads + * and try to replace current Load or Store by a previous one. + * Note that in unreachable loops it might happen that we reach + * load again, as well as we can fall into a cycle. + * We break such cycles using a special visited flag. + */ + INC_MASTER(); + for (pred = skip_Proj(mem); load != pred; pred = skip_Proj(get_Load_mem(pred))) { + ldst_info_t *pred_info = get_irn_link(pred); + /* - * a load immediately after a load -- a read after read. - * We may remove the second Load, if it does not have an exception handler - * OR they are in the same block. In the later case the Load cannot - * throw an exception when the previous Load was quiet. + * BEWARE: one might think that checking the modes is useless, because + * if the pointers are identical, they refer to the same object. + * This is only true in strong typed languages, not in C were the following + * is possible a = *(ir_type1 *)p; b = *(ir_type2 *)p ... */ - if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { - ldst_info_t *pred_info = get_irn_link(pred); - - if (pred_info->projs[pn_Load_res]) { - /* we need a data proj from the previous load for this optimization */ - exchange( info->projs[pn_Load_res], pred_info->projs[pn_Load_res] ); - if (info->projs[pn_Load_M]) - exchange(info->projs[pn_Load_M], mem); + + if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && + get_irn_mode(get_Store_value(pred)) == load_mode) { + /* + * a Load immediately after a Store -- a read after write. + * We may remove the Load, if both Load & Store does not have an exception handler + * OR they are in the same block. In the latter case the Load cannot + * throw an exception when the previous Store was quiet. + * + * Why we need to check for Store Exception? If the Store cannot + * be executed (ROM) the exception handler might simply jump into + * the load block :-( + * We could make it a little bit better if we would know that the exception + * handler of the Store jumps directly to the end... + */ + if ((!pred_info->projs[pn_Store_X_except] && !info->projs[pn_Load_X_except]) || + get_nodes_block(load) == get_nodes_block(pred)) { + ir_node *value = get_Store_value(pred); + + DBG_OPT_RAW(load, value); + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + + /* no exception */ + if (info->projs[pn_Load_X_except]) { + exchange( info->projs[pn_Load_X_except], new_Bad()); + res |= CF_CHANGED; + } + + if (info->projs[pn_Load_res]) + exchange(info->projs[pn_Load_res], value); + + return res | DF_CHANGED; } - else { - if (info->projs[pn_Load_res]) { - set_Proj_pred(info->projs[pn_Load_res], pred); - set_nodes_block(info->projs[pn_Load_res], get_nodes_block(pred)); - } - if (info->projs[pn_Load_M]) { - /* Actually, this if should not be necessary. Construct the Loads - properly!!! */ - exchange(info->projs[pn_Load_M], mem); - } + } + else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && + get_Load_mode(pred) == load_mode) { + /* + * a Load after a Load -- a read after read. + * We may remove the second Load, if it does not have an exception handler + * OR they are in the same block. In the later case the Load cannot + * throw an exception when the previous Load was quiet. + * + * Here, there is no need to check if the previous Load has an exception + * hander because they would have exact the same exception... + */ + if (! info->projs[pn_Load_X_except] || get_nodes_block(load) == get_nodes_block(pred)) { + DBG_OPT_RAR(load, pred); + + if (pred_info->projs[pn_Load_res]) { + /* we need a data proj from the previous load for this optimization */ + if (info->projs[pn_Load_res]) + exchange(info->projs[pn_Load_res], pred_info->projs[pn_Load_res]); + + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + } + else { + if (info->projs[pn_Load_res]) { + set_Proj_pred(info->projs[pn_Load_res], pred); + set_nodes_block(info->projs[pn_Load_res], get_nodes_block(pred)); + pred_info->projs[pn_Load_res] = info->projs[pn_Load_res]; + } + if (info->projs[pn_Load_M]) { + /* Actually, this if should not be necessary. Construct the Loads + properly!!! */ + exchange(info->projs[pn_Load_M], mem); + } + } + + /* no exception */ + if (info->projs[pn_Load_X_except]) { + exchange(info->projs[pn_Load_X_except], new_Bad()); + res |= CF_CHANGED; + } + + return res |= DF_CHANGED; } + } - /* no exception */ - if (info->projs[pn_Load_X_except]) - exchange(info->projs[pn_Load_X_except], new_Bad()); + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; - res = 1; - } + /* check for cycles */ + if (NODE_VISITED(pred_info)) + break; + MARK_NODE(pred_info); } return res; } @@ -225,13 +687,12 @@ static int optimize_load(ir_node *load) /** * optimize a Store */ -static int optimize_store(ir_node *store) +static unsigned optimize_store(ir_node *store) { ldst_info_t *info = get_irn_link(store); ir_node *pred, *mem, *ptr, *value, *block; ir_mode *mode; - ldst_info_t *pred_info; - int res = 0; + unsigned res = 0; if (get_Store_volatility(store) == volatility_is_volatile) return 0; @@ -240,71 +701,96 @@ static int optimize_store(ir_node *store) * BEWARE: one might think that checking the modes is useless, because * if the pointers are identical, they refer to the same object. * This is only true in strong typed languages, not is C were the following - * is possible *(type1 *)p = a; *(type2 *)p = b ... + * is possible *(ir_type1 *)p = a; *(ir_type2 *)p = b ... */ - block = get_nodes_block(store); ptr = get_Store_ptr(store); + + /* Check, if the address of this load is used more than once. + * If not, this load cannot be removed in any case. */ + if (get_irn_out_n(ptr) <= 1) + return 0; + + block = get_nodes_block(store); mem = get_Store_mem(store); value = get_Store_value(store); - pred = skip_Proj(mem); mode = get_irn_mode(value); - pred_info = get_irn_link(pred); - - if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && - get_nodes_block(pred) == block && get_irn_mode(get_Store_value(pred)) == mode) { - /* - * a store immediately after a store in the same block -- a write after write. - * We may remove the first Store, if it does not have an exception handler. - * - * TODO: What, if both have the same exception handler ??? - */ - if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) { - exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) ); - res = 1; + /* follow the memory chain as long as there are only Loads */ + INC_MASTER(); + for (pred = skip_Proj(mem); pred != store; pred = skip_Proj(get_Load_mem(pred))) { + ldst_info_t *pred_info = get_irn_link(pred); + + if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && + get_nodes_block(pred) == block && get_irn_mode(get_Store_value(pred)) == mode) { + /* + * a Store after a Store in the same block -- a write after write. + * We may remove the first Store, if it does not have an exception handler. + * + * TODO: What, if both have the same exception handler ??? + */ + if (get_Store_volatility(pred) != volatility_is_volatile && !pred_info->projs[pn_Store_X_except]) { + DBG_OPT_WAW(pred, store); + exchange( pred_info->projs[pn_Store_M], get_Store_mem(pred) ); + return DF_CHANGED; + } } - } - else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && - value == pred_info->projs[pn_Load_res]) { - /* - * a store a value immediately after a load -- a write after read. - * We may remove the second Store, if it does not have an exception handler. - */ - if (! info->projs[pn_Store_X_except]) { - exchange( info->projs[pn_Store_M], mem ); - res = 1; + else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && + value == pred_info->projs[pn_Load_res]) { + /* + * a Store of a value after a Load -- a write after read. + * We may remove the second Store, if it does not have an exception handler. + */ + if (! info->projs[pn_Store_X_except]) { + DBG_OPT_WAR(store, pred); + exchange( info->projs[pn_Store_M], mem ); + return DF_CHANGED; + } } + + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; + + /* check for cycles */ + if (NODE_VISITED(pred_info)) + break; + MARK_NODE(pred_info); } return res; } /** - * walker, optimizes Phi after Stores: + * walker, optimizes Phi after Stores to identical places: * Does the following optimization: + * @verbatim * * val1 val2 val3 val1 val2 val3 * | | | \ | / * Str Str Str \ | / - * \ | / Phi + * \ | / PhiData * \ | / | * \ | / Str - * Phi + * PhiM * - * This removes teh number of stores and allows for predicated execution. - * Moves Stores back to the end of a function which may be bad + * @endverbatim + * This reduces the number of stores and allows for predicated execution. + * Moves Stores back to the end of a function which may be bad. * - * Note: that even works, if one of the Stores is already in our current block + * This is only possible if the predecessor blocks have only one successor. */ -static int optimize_phi(ir_node *phi) +static unsigned optimize_phi(ir_node *phi, void *env) { + walk_env_t *wenv = env; int i, n; - ir_node *store, *ptr, *block, *phiM, *phiD, *exc; + ir_node *store, *old_store, *ptr, *block, *phiM, *phiD, *exc, *projM; ir_mode *mode; ir_node **inM, **inD; int *idx; dbg_info *db = NULL; ldst_info_t *info; + block_info_t *bl_info; + unsigned res = 0; /* Must be a memory Phi */ if (get_irn_mode(phi) != mode_M) @@ -315,9 +801,19 @@ static int optimize_phi(ir_node *phi) return 0; store = skip_Proj(get_Phi_pred(phi, 0)); + old_store = store; if (get_irn_op(store) != op_Store) return 0; + /* abort on dead blocks */ + if (is_Block_dead(get_nodes_block(store))) + return 0; + + /* check if the block has only one successor */ + bl_info = get_irn_link(get_nodes_block(store)); + if (bl_info->flags) + return 0; + /* this is the address of the store */ ptr = get_Store_ptr(store); mode = get_irn_mode(get_Store_value(store)); @@ -330,7 +826,7 @@ static int optimize_phi(ir_node *phi) if (get_irn_op(pred) != op_Store) return 0; - if (mode != get_irn_mode(get_Store_value(pred)) || ptr != get_Store_ptr(pred)) + if (ptr != get_Store_ptr(pred) || mode != get_irn_mode(get_Store_value(pred))) return 0; info = get_irn_link(pred); @@ -338,23 +834,32 @@ static int optimize_phi(ir_node *phi) /* check, if all stores have the same exception flow */ if (exc != info->exc_block) return 0; + + /* abort on dead blocks */ + if (is_Block_dead(get_nodes_block(store))) + return 0; + + /* check if the block has only one successor */ + bl_info = get_irn_link(get_nodes_block(store)); + if (bl_info->flags) + return 0; } /* * ok, when we are here, we found all predecessors of a Phi that - * are Stores to the same address. That means whatever we do before - * we enter the block of the Phi, we do a Store. - * So, we can move the store to the current block: + * are Stores to the same address and size. That means whatever + * we do before we enter the block of the Phi, we do a Store. + * So, we can move the Store to the current block: * * val1 val2 val3 val1 val2 val3 * | | | \ | / * | Str | | Str | | Str | \ | / - * \ | / Phi + * \ | / PhiData * \ | / | * \ | / Str - * Phi + * PhiM * - * Note: that even works, if one of the Stores is already in our current block + * Is only allowed if the predecessor blocks have only one successor. */ /* first step: collect all inputs */ @@ -380,11 +885,23 @@ static int optimize_phi(ir_node *phi) /* fourth step: create the Store */ store = new_rd_Store(db, current_ir_graph, block, phiM, ptr, phiD); +#ifdef DO_CACHEOPT + co_set_irn_name(store, co_get_irn_ident(old_store)); +#endif + + projM = new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M); + + info = get_ldst_info(store, wenv); + info->projs[pn_Store_M] = projM; /* fifths step: repair exception flow */ if (exc) { ir_node *projX = new_rd_Proj(NULL, current_ir_graph, block, store, mode_X, pn_Store_X_except); + info->projs[pn_Store_X_except] = projX; + info->exc_block = exc; + info->exc_idx = idx[0]; + for (i = 0; i < n; ++i) { set_Block_cfgpred(exc, idx[i], projX); } @@ -392,16 +909,18 @@ static int optimize_phi(ir_node *phi) if (n > 1) { /* the exception block should be optimized as some inputs are identical now */ } + + res |= CF_CHANGED; } - /* sixt step: replace old Phi */ - exchange(phi, new_rd_Proj(NULL, current_ir_graph, block, store, mode_M, pn_Store_M)); + /* sixth step: replace old Phi */ + exchange(phi, projM); - return 1; + return res | DF_CHANGED; } /** - * walker, collects all Load/Store/Proj nodes + * walker, do the optimizations */ static void do_load_store_optimize(ir_node *n, void *env) { @@ -418,7 +937,7 @@ static void do_load_store_optimize(ir_node *n, void *env) break; case iro_Phi: - wenv->changes |= optimize_phi(n); + wenv->changes |= optimize_phi(n, env); default: ; @@ -433,15 +952,18 @@ void optimize_load_store(ir_graph *irg) walk_env_t env; assert(get_irg_phase_state(irg) != phase_building); + assert(get_irg_pinned(irg) != op_pin_state_floats && + "LoadStore optimization needs pinned graph"); - if (!get_opt_redundant_LoadStore()) + if (! get_opt_redundant_loadstore()) return; obstack_init(&env.obst); env.changes = 0; /* init the links, then collect Loads/Stores/Proj's in lists */ - irg_walk_graph(irg, init_links, collect_nodes, &env); + master_visited = 0; + irg_walk_graph(irg, firm_clear_link, collect_nodes, &env); /* now we have collected enough information, optimize */ irg_walk_graph(irg, NULL, do_load_store_optimize, &env); @@ -452,9 +974,10 @@ void optimize_load_store(ir_graph *irg) if (env.changes) { if (get_irg_outs_state(current_ir_graph) == outs_consistent) set_irg_outs_inconsistent(current_ir_graph); + } - /* is this really needed: Yes, as exception block may get bad but this might be tested */ - if (get_irg_dom_state(current_ir_graph) == dom_consistent) - set_irg_dom_inconsistent(current_ir_graph); + if (env.changes & CF_CHANGED) { + /* is this really needed: Yes, control flow changed, block might get Bad. */ + set_irg_doms_inconsistent(current_ir_graph); } }