X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fldstopt.c;h=d5358791797c6785cb8362fee62dfff30fb89c6c;hb=5992483ac7f47c78e5315897faf715fc840f32ce;hp=e8081cd7e65c27f8b6878ca0c6317b5caade6b5d;hpb=0fe16709e2f7fdf8438b85c8167621041d00b22b;p=libfirm diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c index e8081cd7e..d53587917 100644 --- a/ir/opt/ldstopt.c +++ b/ir/opt/ldstopt.c @@ -5,9 +5,23 @@ * Author: * Created: * CVS-ID: $Id$ - * Copyright: (c) 1998-2004 Universität Karlsruhe + * 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" @@ -20,7 +34,13 @@ # include "dbginfo_t.h" # include "iropt_dbg.h" # include "irflag_t.h" -# include "firmstat.h" +# include "array.h" +# include "irhooks.h" +# include "opt_polymorphy.h" + +#ifdef DO_CACHEOPT +#include "cacheopt/cachesim.h" +#endif #undef IMAX #define IMAX(a,b) ((a) > (b) ? (a) : (b)) @@ -35,13 +55,38 @@ typedef struct _walk_env_t { int 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 *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 */ } ldst_info_t; +/** + * flags for control flow + */ +enum block_flags_t { + BLOCK_HAS_COND = 1, /**< Block has conditional control flow */ + BLOCK_HAS_EXC = 2 /**< Block has exceptionl control flow */ +}; + +/** + * a Block info + */ +typedef struct _block_info_t { + unsigned flags; /**< flags for the block */ +} block_info_t; + /** * walker, clears all links first */ @@ -53,7 +98,7 @@ static void init_links(ir_node *n, void *env) /** * 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); @@ -68,9 +113,26 @@ static ldst_info_t *get_info(ir_node *node, walk_env_t *env) } /** - * update the info for a Load/Store + * 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 void update_projs(ldst_info_t *info, ir_node *proj) +static int update_projs(ldst_info_t *info, ir_node *proj) { long nr = get_Proj_proj(proj); @@ -79,31 +141,204 @@ static void 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; } - else + else { info->projs[nr] = proj; + return 0; + } +} + +/** + * update the exception block info for a Load/Store + */ +static int update_exc(ldst_info_t *info, ir_node *block, int pos) +{ + assert(info->exc_block == NULL && "more than one exception block found"); + + info->exc_block = block; + info->exc_idx = pos; + return 0; } +#define get_irn_out_n(node) (unsigned)get_irn_link(node) +#define set_irn_out_n(node, n) set_irn_link(adr, (void *)(n)) + /** * walker, collects all Load/Store/Proj nodes + * + * walks form Start -> End */ -static void collect_nodes(ir_node *n, void *env) +static void collect_nodes(ir_node *node, void *env) { + ir_op *op = get_irn_op(node); ir_node *pred; - ldst_info_t *info; + ldst_info_t *ldst_info; walk_env_t *wenv = env; - if (get_irn_op(n) == op_Proj) { - pred = get_Proj_pred(n); + if (op == op_Proj) { + ir_node *adr; + ir_op *op; - if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) { - info = get_info(pred, wenv); + pred = get_Proj_pred(node); + op = get_irn_op(pred); - update_projs(info, n); + if (op == op_Load) { + ldst_info = get_ldst_info(pred, wenv); + + wenv->changes |= update_projs(ldst_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; + } + } + 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; + } + } + } + else if (op == op_Block) { /* check, if it's an exception block */ + int i, n; + + for (i = 0, n = get_Block_n_cfgpreds(node); i < n; ++i) { + ir_node *pred_block; + block_info_t *bl_info; + + 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_forking_op(pred)) + bl_info->flags |= BLOCK_HAS_COND; + + if (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store) { + 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); + + 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); + type *tp = get_entity_owner(ent); + + /* Do not fiddle about polymorphy. */ + 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; + } +} + +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)); +} + +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) { + 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); + res = rec_get_accessed_path(get_Sel_ptr(ptr), depth+1); + 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 */ @@ -111,77 +346,269 @@ static int 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; + int res = 0; - 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 form a Load: + * this can be done, if the address is from an Sel(Alloc) and + * the Sel type is a subtype of the alloc type. + * + * This optimizes some often used OO constructs, + * like x = new O; x->t; */ + if (info->projs[pn_Load_X_except]) { + if (get_irn_op(ptr) == op_Sel) { + 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); + type *s_type = get_entity_type(ent); + 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; + } + } + } + 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; + } + } - ptr = get_Load_ptr(load); - mem = get_Load_mem(load); - pred = skip_Proj(mem); + /* do NOT touch volatile loads for now */ + if (get_Load_volatility(load) == volatility_is_volatile) + return 0; if (! info->projs[pn_Load_res] && ! info->projs[pn_Load_X_except]) { /* a Load which value is neither used nor exception checked, remove it */ + mem = get_Load_mem(load); exchange(info->projs[pn_Load_M], mem); - res = 1; + + return 1; } - 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) ); - 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; + /* the mem of the Load. Must still be returned after optimization */ + mem = get_Load_mem(load); + + /* Load from a constant polymorphic field, where we can resolve + polymorphy. */ + 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 1; } - else if (get_irn_op(pred) == op_Load && get_Load_ptr(pred) == ptr && - get_Load_mode(pred) == load_mode) { - /* - * 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 latter case the Load cannot - * throw an exception when the previous Load was quiet. - */ - 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] ); - exchange( info->projs[pn_Load_M], mem ); + /* 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; } - 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 (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); + + /* no result :-) */ + if (info->projs[pn_Load_res]) { + if (is_atomic_entity(ent)) { + ir_node *c = copy_const_value(get_atomic_ent_value(ent)); + + DBG_OPT_RC(load, c); + exchange(info->projs[pn_Load_res], c); + + return 1; + } + } + } + else if (variability_constant == get_entity_variability(ent)) { + compound_graph_path *path; + /* + 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); + */ + path = get_accessed_path(ptr); + if (path) { + ir_node *c; + + assert(is_proper_compound_graph_path(path, get_compound_graph_path_length(path)-1)); + c = get_compound_ent_value_by_path(ent, path); + + /* printf(" cons: "); DDMN(c); */ + + if (info->projs[pn_Load_M]) + exchange(info->projs[pn_Load_M], mem); + if (info->projs[pn_Load_res]) + exchange(info->projs[pn_Load_res], copy_const_value(c)); + /* + { + 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"); + } + */ + } 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); + if (get_irn_op(ptr) == op_SymConst && + get_SymConst_kind(ptr) == symconst_addr_ent) { printf(" "); DDMEO(get_SymConst_entity(ptr)); } + printf("cannot optimize.\n"); + */ } - 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()); - + /* we changed the irg, but try further */ res = 1; } } + + /* 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; + + /* follow the memory chain as long as there are only Loads */ + for (pred = skip_Proj(mem); ; pred = skip_Proj(get_Load_mem(pred))) { + + /* + * 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 ... + */ + + if (get_irn_op(pred) == op_Store && get_Store_ptr(pred) == ptr && + get_irn_mode(get_Store_value(pred)) == load_mode) { + ldst_info_t *pred_info = get_irn_link(pred); + + /* + * 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 Exc? 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); + exchange(info->projs[pn_Load_res], 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()); + return 1; + } + } + 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 previos 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)) { + ldst_info_t *pred_info = get_irn_link(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 */ + 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)); + } + 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()); + + return 1; + } + } + + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; + } return res; } @@ -193,7 +620,6 @@ static int 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; if (get_Store_volatility(store) == volatility_is_volatile) @@ -206,42 +632,210 @@ static int optimize_store(ir_node *store) * is possible *(type1 *)p = a; *(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 */ + for (pred = skip_Proj(mem); ; 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 1; + } } - } - 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 1; + } } + + /* follow only Load chains */ + if (get_irn_op(pred) != op_Load) + break; } return res; } +/** + * walker, optimizes Phi after Stores: + * Does the following optimization: + * + * val1 val2 val3 val1 val2 val3 + * | | | \ | / + * Str Str Str \ | / + * \ | / Phi + * \ | / | + * \ | / Str + * Phi + * + * This removes the number of stores and allows for predicated execution. + * Moves Stores back to the end of a function which may be bad + * + * Is only allowed if the predecessor blocks have only one successor. + */ +static int optimize_phi(ir_node *phi, void *env) +{ + walk_env_t *wenv = env; + int i, n; + 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; + + /* Must be a memory Phi */ + if (get_irn_mode(phi) != mode_M) + return 0; + + n = get_Phi_n_preds(phi); + if (n <= 0) + return 0; + + store = skip_Proj(get_Phi_pred(phi, 0)); + old_store = store; + if (get_irn_op(store) != op_Store) + return 0; + + /* abort on bad blocks */ + if (is_Bad(get_nodes_block(store))) + return 0; + + /* check if the block has only one output */ + 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)); + info = get_irn_link(store); + exc = info->exc_block; + + for (i = 1; i < n; ++i) { + ir_node *pred = skip_Proj(get_Phi_pred(phi, i)); + + if (get_irn_op(pred) != op_Store) + return 0; + + if (mode != get_irn_mode(get_Store_value(pred)) || ptr != get_Store_ptr(pred)) + return 0; + + info = get_irn_link(pred); + + /* check, if all stores have the same exception flow */ + if (exc != info->exc_block) + return 0; + + /* abort on bad blocks */ + if (is_Bad(get_nodes_block(store))) + return 0; + + /* check if the block has only one output */ + 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: + * + * val1 val2 val3 val1 val2 val3 + * | | | \ | / + * | Str | | Str | | Str | \ | / + * \ | / Phi + * \ | / | + * \ | / Str + * Phi + * + * Is only allowed if the predecessor blocks have only one successor. + */ + + /* first step: collect all inputs */ + NEW_ARR_A(ir_node *, inM, n); + NEW_ARR_A(ir_node *, inD, n); + NEW_ARR_A(int, idx, n); + + for (i = 0; i < n; ++i) { + ir_node *pred = skip_Proj(get_Phi_pred(phi, i)); + info = get_irn_link(pred); + + inM[i] = get_Store_mem(pred); + inD[i] = get_Store_value(pred); + idx[i] = info->exc_idx; + } + block = get_nodes_block(phi); + + /* second step: create a new memory Phi */ + phiM = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inM, mode_M); + + /* third step: create a new data Phi */ + phiD = new_rd_Phi(get_irn_dbg_info(phi), current_ir_graph, block, n, inD, mode); + + /* 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); + } + + if (n > 1) { + /* the exception block should be optimized as some inputs are identical now */ + } + } + + /* sixt step: replace old Phi */ + exchange(phi, projM); + + return 1; +} + /** * walker, collects all Load/Store/Proj nodes */ @@ -259,6 +853,9 @@ static void do_load_store_optimize(ir_node *n, void *env) wenv->changes |= optimize_store(n); break; + case iro_Phi: + wenv->changes |= optimize_phi(n, env); + default: ; }