From 39c28e0703835288061e6b1161fe05b96fe55bfd Mon Sep 17 00:00:00 2001 From: Michael Beck Date: Mon, 10 Dec 2007 16:28:52 +0000 Subject: [PATCH] - handle pure Calls like Load nodes - remove unused code [r16933] --- ir/opt/ldstopt.c | 114 ++++++++++++++++++++++++----------------------- 1 file changed, 59 insertions(+), 55 deletions(-) diff --git a/ir/opt/ldstopt.c b/ir/opt/ldstopt.c index 33eeddd12..3af1d8703 100644 --- a/ir/opt/ldstopt.c +++ b/ir/opt/ldstopt.c @@ -63,7 +63,7 @@ DEBUG_ONLY(static firm_dbg_module_t *dbg;) #undef IMAX #define IMAX(a,b) ((a) > (b) ? (a) : (b)) -#define MAX_PROJ IMAX(pn_Load_max, pn_Store_max) +#define MAX_PROJ IMAX(IMAX(pn_Load_max, pn_Store_max), pn_Call_max) enum changes_t { DF_CHANGED = 1, /**< data flow changed */ @@ -78,19 +78,11 @@ typedef struct _walk_env_t { 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 */ - unsigned flags; /**< flags */ unsigned visited; /**< visited counter for breaking loops */ } ldst_info_t; @@ -190,28 +182,20 @@ static unsigned update_exc(ldst_info_t *info, ir_node *block, int pos) */ static void collect_nodes(ir_node *node, void *env) { - ir_op *op = get_irn_op(node); + ir_opcode opcode = get_irn_opcode(node); ir_node *pred, *blk, *pred_blk; ldst_info_t *ldst_info; walk_env_t *wenv = env; - if (op == op_Proj) { - ir_node *adr; - ir_op *op; - - pred = get_Proj_pred(node); - op = get_irn_op(pred); + if (opcode == iro_Proj) { + pred = get_Proj_pred(node); + opcode = get_irn_opcode(pred); - if (op == op_Load) { + if (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call) { ldst_info = get_ldst_info(pred, &wenv->obst); wenv->changes |= update_projs(ldst_info, node); - if ((ldst_info->flags & LDST_VISITED) == 0) { - adr = get_Load_ptr(pred); - ldst_info->flags |= LDST_VISITED; - } - /* * Place the Proj's to the same block as the * predecessor Load. This is always ok and prevents @@ -224,30 +208,8 @@ static void collect_nodes(ir_node *node, void *env) wenv->changes |= DF_CHANGED; set_nodes_block(node, pred_blk); } - } else if (op == op_Store) { - ldst_info = get_ldst_info(pred, &wenv->obst); - - wenv->changes |= update_projs(ldst_info, node); - - if ((ldst_info->flags & LDST_VISITED) == 0) { - adr = get_Store_ptr(pred); - 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 (op == op_Block) { + } else if (opcode == iro_Block) { int i; for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) { @@ -274,7 +236,8 @@ static void collect_nodes(ir_node *node, void *env) else if (is_irn_forking(pred)) bl_info->flags |= BLOCK_HAS_COND; - if (is_exc && (get_irn_op(pred) == op_Load || get_irn_op(pred) == op_Store)) { + opcode = get_irn_opcode(pred); + if (is_exc && (opcode == iro_Load || opcode == iro_Store || opcode == iro_Call)) { ldst_info = get_ldst_info(pred, &wenv->obst); wenv->changes |= update_exc(ldst_info, node, i); @@ -472,9 +435,30 @@ static int can_use_stored_value(ir_mode *old_mode, ir_mode *new_mode) { } /* can_use_stored_value */ /** - * Follow the memory chain as long as there are only Loads - * and alias free Stores and try to replace current Load or Store - * by a previous ones. + * Check whether a Call is at least pure, ie. does only read memory. + */ +static unsigned is_Call_pure(ir_node *call) { + ir_type *call_tp = get_Call_type(call); + unsigned prop = get_method_additional_properties(call_tp); + + /* check first the call type */ + if ((prop & (mtp_property_const|mtp_property_pure)) == 0) { + /* try the called entity */ + ir_node *ptr = get_Call_ptr(call); + + if (is_SymConst(ptr) && get_SymConst_kind(ptr) == symconst_addr_ent) { + ir_entity *ent = get_SymConst_entity(ptr); + + prop = get_entity_additional_properties(ent); + } + } + return (prop & (mtp_property_const|mtp_property_pure)) != 0; +} /* is_Call_pure */ + +/** + * Follow the memory chain as long as there are only Loads, + * alias free Stores, and constant Calls and try to replace the + * current Load by a previous ones. * 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. @@ -605,8 +589,17 @@ static unsigned follow_Mem_chain(ir_node *load, ir_node *curr) { if (rel != no_alias) break; pred = skip_Proj(get_Store_mem(pred)); - } else if (get_irn_op(pred) == op_Load) { + } else if (is_Load(pred)) { pred = skip_Proj(get_Load_mem(pred)); + } else if (is_Call(pred)) { + if (is_Call_pure(pred)) { + /* The called graph is at least pure, so there are no Store's + in it. We can handle it like a Load and skip it. */ + pred = skip_Proj(get_Call_mem(pred)); + } else { + /* there might be Store's in the graph, stop here */ + break; + } } else { /* follow only Load chains */ break; @@ -1305,9 +1298,12 @@ struct phi_entry { }; /** - * Move loops out of loops if possible + * Move loops out of loops if possible. + * + * @param pscc the loop described by an SCC + * @param env the loop environment */ -static void move_loads_in_loops(scc *pscc, loop_env *env) { +static void move_loads_out_of_loops(scc *pscc, loop_env *env) { ir_node *phi, *load, *next, *other, *next_other; ir_entity *ent; int j; @@ -1374,6 +1370,7 @@ static void move_loads_in_loops(scc *pscc, loop_env *env) { if (rel != no_alias) break; } + /* only pure Calls are allowed here, so ignore them */ } if (other == NULL) { ldst_info_t *ninfo; @@ -1414,7 +1411,7 @@ static void move_loads_in_loops(scc *pscc, loop_env *env) { } } } -} /* move_loads_in_loops */ +} /* move_loads_out_of_loops */ /** * Process a loop SCC. @@ -1458,8 +1455,15 @@ static void process_loop(scc *pscc, loop_env *env) { next = e->next; switch (get_irn_opcode(irn)) { case iro_Call: + if (is_Call_pure(irn)) { + /* pure calls can be treated like loads */ + only_phi = 0; + break; + } + /* non-pure calls must be handle like may-alias Stores */ + goto fail; case iro_CopyB: - /* cannot handle Calls or CopyB yet */ + /* cannot handle CopyB yet */ goto fail; case iro_Load: process = 1; @@ -1529,7 +1533,7 @@ static void process_loop(scc *pscc, loop_env *env) { } DB((dbg, LEVEL_2, "\n")); - move_loads_in_loops(pscc, env); + move_loads_out_of_loops(pscc, env); fail: ; -- 2.20.1