X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fir%2Firopt.c;h=51e8854750cbd4c82c243762d1ab750553f18630;hb=eb47aca33f2f8c414409f3695e73277b47442334;hp=2de4ec1489b43208141c48009de62d1641164bbc;hpb=fc9bc377a4efe064fe1998121e52ba97ce4da415;p=libfirm diff --git a/ir/ir/iropt.c b/ir/ir/iropt.c index 2de4ec148..51e885475 100644 --- a/ir/ir/iropt.c +++ b/ir/ir/iropt.c @@ -672,10 +672,6 @@ static ir_op_ops *firm_set_default_computed_value(ir_opcode code, ir_op_ops *ops * * If all predecessors of a block are bad or lies in a dead * block, the current block is dead as well. - * - * Note, that blocks are NEVER turned into Bad's, instead - * the dead_block flag is set. So, never test for is_Bad(block), - * always use is_dead_Block(block). */ static ir_node *equivalent_node_Block(ir_node *n) { @@ -684,7 +680,7 @@ static ir_node *equivalent_node_Block(ir_node *n) ir_graph *irg; /* don't optimize dead or labeled blocks */ - if (is_Block_dead(n) || has_Block_entity(n)) + if (has_Block_entity(n)) return n; n_preds = get_Block_n_cfgpreds(n); @@ -695,32 +691,34 @@ static ir_node *equivalent_node_Block(ir_node *n) irg = get_irn_irg(n); + /* if all predecessors of a block are unreachable, then the block is + * unreachable */ + if (is_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK)) { + int i; + int n_cfgpreds = get_Block_n_cfgpreds(n); + + for (i = 0; i < n_cfgpreds; ++i) { + ir_node *pred = get_Block_cfgpred(n, i); + if (!is_Bad(pred)) + break; + } + /* only bad inputs? It's unreachable code (unless it is the start or + * end block) */ + if (i >= n_cfgpreds && n != get_irg_start_block(irg) + && n != get_irg_end_block(irg)) { + return get_irg_bad(irg); + } + } + /* Straightening: a single entry Block following a single exit Block - can be merged, if it is not the Start block. */ - /* !!! Beware, all Phi-nodes of n must have been optimized away. - This should be true, as the block is matured before optimize is called. - But what about Phi-cycles with the Phi0/Id that could not be resolved? - Remaining Phi nodes are just Ids. */ + * can be merged. */ if (n_preds == 1) { - ir_node *pred = skip_Proj(get_Block_cfgpred(n, 0)); + ir_node *pred = get_Block_cfgpred(n, 0); if (is_Jmp(pred)) { - ir_node *predblock = get_nodes_block(pred); - if (predblock == oldn) { - /* Jmp jumps into the block it is in -- deal self cycle. */ - n = set_Block_dead(n); - DBG_OPT_DEAD_BLOCK(oldn, n); - } else { - n = predblock; - DBG_OPT_STG(oldn, n); - } - } else if (is_Cond(pred)) { - ir_node *predblock = get_nodes_block(pred); - if (predblock == oldn) { - /* Jmp jumps into the block it is in -- deal self cycle. */ - n = set_Block_dead(n); - DBG_OPT_DEAD_BLOCK(oldn, n); - } + ir_node *pred_block = get_nodes_block(pred); + DBG_OPT_STG(n, pred_block); + return pred_block; } } else if (n_preds == 2) { /* Test whether Cond jumps twice to this block @@ -735,64 +733,18 @@ static ir_node *equivalent_node_Block(ir_node *n) if (cond == get_Proj_pred(b) && is_Cond(cond) && get_irn_mode(get_Cond_selector(cond)) == mode_b) { - /* Also a single entry Block following a single exit Block. Phis have - twice the same operand and will be optimized away. */ + /* Also a single entry Block following a single exit Block. + * Phis have twice the same operand and will be optimized away. + */ n = get_nodes_block(cond); DBG_OPT_IFSIM1(oldn, a, b, n); } } - } else if (get_opt_unreachable_code() && - (n != get_irg_start_block(irg)) && - (n != get_irg_end_block(irg))) { - int i; - - /* If all inputs are dead, this block is dead too, except if it is - the start or end block. This is one step of unreachable code - elimination */ - for (i = get_Block_n_cfgpreds(n) - 1; i >= 0; --i) { - ir_node *pred = get_Block_cfgpred(n, i); - ir_node *pred_blk; - - if (is_Bad(pred)) continue; - pred_blk = get_nodes_block(skip_Proj(pred)); - - if (is_Block_dead(pred_blk)) continue; - - if (pred_blk != n) { - /* really found a living input */ - break; - } - } - if (i < 0) { - n = set_Block_dead(n); - DBG_OPT_DEAD_BLOCK(oldn, n); - } } return n; } /* equivalent_node_Block */ -/** - * Returns a equivalent node for a Jmp, a Bad :-) - * Of course this only happens if the Block of the Jmp is dead. - */ -static ir_node *equivalent_node_Jmp(ir_node *n) -{ - ir_node *oldn = n; - - /* unreachable code elimination */ - if (is_Block_dead(get_nodes_block(n))) { - ir_graph *irg = get_irn_irg(n); - n = get_irg_bad(irg); - DBG_OPT_DEAD_BLOCK(oldn, n); - } - return n; -} /* equivalent_node_Jmp */ - -/** Raise is handled in the same way as Jmp. */ -#define equivalent_node_Raise equivalent_node_Jmp - - /* We do not evaluate Cond here as we replace it by a new node, a Jmp. See transform_node_Proj_Cond(). */ @@ -1309,31 +1261,18 @@ static ir_node *equivalent_node_Phi(ir_node *n) n_preds = get_Phi_n_preds(n); block = get_nodes_block(n); - /* Control dead */ - if (is_Block_dead(block)) { - ir_graph *irg = get_irn_irg(n); - return get_irg_bad(irg); - } - if (n_preds == 0) return n; /* Phi of dead Region without predecessors. */ + /* Phi of dead Region without predecessors. */ + if (n_preds == 0) + return n; /* Find first non-self-referencing input */ for (i = 0; i < n_preds; ++i) { first_val = get_Phi_pred(n, i); - if ( (first_val != n) /* not self pointer */ -#if 0 - /* BEWARE: when the if is changed to 1, Phis will ignore their Bad - * predecessors. Then, Phi nodes in unreachable code might be removed, - * causing nodes pointing to themselev (Adds for instance). - * This is really bad and causes endless recursion on several - * code pathes, so we do NOT optimize such code. - * This is not that bad as it sounds, optimize_cf() removes bad control flow - * (and bad Phi predecessors), so live code is optimized later. - */ - && (! is_Bad(get_Block_cfgpred(block, i))) -#endif - ) { /* value not dead */ - break; /* then found first value. */ + /* not self pointer */ + if (first_val != n) { + /* then found first value. */ + break; } } @@ -1347,13 +1286,7 @@ static ir_node *equivalent_node_Phi(ir_node *n) are non-self-referencing */ while (++i < n_preds) { ir_node *scnd_val = get_Phi_pred(n, i); - if ( (scnd_val != n) - && (scnd_val != first_val) -#if 0 - /* see above */ - && (! is_Bad(get_Block_cfgpred(block, i))) -#endif - ) { + if (scnd_val != n && scnd_val != first_val) { break; } } @@ -1598,14 +1531,6 @@ static ir_node *equivalent_node_Proj_Store(ir_node *proj) static ir_node *equivalent_node_Proj(ir_node *proj) { ir_node *n = get_Proj_pred(proj); - - if (get_irn_mode(proj) == mode_X) { - if (is_Block_dead(get_nodes_block(n))) { - /* Remove dead control flow -- early gigo(). */ - ir_graph *irg = get_irn_irg(proj); - return get_irg_bad(irg); - } - } if (n->op->ops.equivalent_node_Proj) return n->op->ops.equivalent_node_Proj(proj); return proj; @@ -1785,8 +1710,6 @@ static ir_op_ops *firm_set_default_equivalent_node(ir_opcode code, ir_op_ops *op switch (code) { CASE(Block); - CASE(Jmp); - CASE(Raise); CASE(Eor); CASE(Add); CASE(Shl); @@ -4566,14 +4489,24 @@ static ir_node *transform_node_Proj(ir_node *proj) return proj; } /* transform_node_Proj */ -/** - * Move Confirms down through Phi nodes. - */ static ir_node *transform_node_Phi(ir_node *phi) { - int i, n; - ir_mode *mode = get_irn_mode(phi); + int n = get_irn_arity(phi); + ir_mode *mode = get_irn_mode(phi); + ir_node *block = get_nodes_block(phi); + ir_graph *irg = get_irn_irg(phi); + ir_node *bad = get_irg_bad(irg); + int i; + /* Set phi-operands for bad-block inputs to bad */ + for (i = 0; i < n; ++i) { + ir_node *pred = get_Block_cfgpred(block, i); + if (!is_Bad(pred)) + continue; + set_irn_n(phi, i, bad); + } + + /* Move Confirms down through Phi nodes. */ if (mode_is_reference(mode)) { n = get_irn_arity(phi); @@ -5385,14 +5318,7 @@ static ir_node *transform_node_End(ir_node *n) for (i = j = 0; i < n_keepalives; ++i) { ir_node *ka = get_End_keepalive(n, i); - if (is_Block(ka)) { - if (! is_Block_dead(ka)) { - in[j++] = ka; - } - continue; - } else if (is_irn_pinned_in_irg(ka) && is_Block_dead(get_nodes_block(ka))) { - continue; - } else if (is_Bad(ka)) { + if (is_Bad(ka)) { /* no need to keep Bad */ continue; } @@ -5714,7 +5640,7 @@ static ir_node *transform_node_Load(ir_node *n) ir_node *block = get_nodes_block(n); ir_node *jmp = new_r_Jmp(block); ir_graph *irg = get_irn_irg(n); - ir_node *bad = new_r_Bad(irg); + ir_node *bad = get_irg_bad(irg); ir_mode *mode = get_Load_mode(n); ir_node *res = new_r_Proj(pred_load, mode, pn_Load_res); ir_node *in[pn_Load_max] = { mem, jmp, bad, res }; @@ -5735,7 +5661,7 @@ static ir_node *transform_node_Load(ir_node *n) ir_node *block = get_nodes_block(n); ir_node *jmp = new_r_Jmp(block); ir_graph *irg = get_irn_irg(n); - ir_node *bad = new_r_Bad(irg); + ir_node *bad = get_irg_bad(irg); ir_node *res = value; ir_node *in[pn_Load_max] = { mem, jmp, bad, res }; ir_node *tuple = new_r_Tuple(block, ARRAY_SIZE(in), in); @@ -5892,11 +5818,8 @@ static ir_op_ops *firm_set_default_transform_node(ir_opcode code, ir_op_ops *ops CASE_PROJ(Store); CASE_PROJ_EX(Cond); CASE_PROJ_EX(Div); + CASE_PROJ_EX(Load); CASE_PROJ_EX(Mod); - case iro_Load: - ops->transform_node = transform_node_Load; - ops->transform_node_Proj = transform_node_Proj_Load; - break; default: /* leave NULL */; } @@ -6353,93 +6276,37 @@ void visit_all_identities(ir_graph *irg, irg_walk_func visit, void *env) */ static ir_node *gigo(ir_node *node) { - int i, irn_arity; ir_op *op = get_irn_op(node); - /* remove garbage blocks by looking at control flow that leaves the block - and replacing the control flow by Bad. */ - if (get_irn_mode(node) == mode_X) { - ir_node *block = get_nodes_block(skip_Proj(node)); - ir_graph *irg = get_irn_irg(block); - - /* Don't optimize nodes in immature blocks. */ - if (!get_Block_matured(block)) - return node; - /* Don't optimize End, may have Bads. */ - if (op == op_End) return node; - - if (is_Block(block)) { - if (is_Block_dead(block)) { - /* control flow from dead block is dead */ - return get_irg_bad(irg); - } - - for (i = get_irn_arity(block) - 1; i >= 0; --i) { - if (!is_Bad(get_irn_n(block, i))) - break; - } - if (i < 0) { - ir_graph *irg = get_irn_irg(block); - /* the start block is never dead */ - if (block != get_irg_start_block(irg) - && block != get_irg_end_block(irg)) { - /* - * Do NOT kill control flow without setting - * the block to dead of bad things can happen: - * We get a Block that is not reachable be irg_block_walk() - * but can be found by irg_walk()! - */ - set_Block_dead(block); - return get_irg_bad(irg); - } - } - } + /* Code in "Bad" blocks is unreachable and can be replaced by Bad */ + if (op != op_Block && is_Bad(get_nodes_block(node))) { + ir_graph *irg = get_irn_irg(node); + return get_irg_bad(irg); } /* Blocks, Phis and Tuples may have dead inputs, e.g., if one of the blocks predecessors is dead. */ - if (op != op_Block && op != op_Phi && op != op_Tuple && op != op_Anchor) { + if (op != op_Block && op != op_Phi && op != op_Tuple && op != op_Anchor + && op != op_Sync && op != op_End) { ir_graph *irg = get_irn_irg(node); - irn_arity = get_irn_arity(node); - - /* - * Beware: we can only read the block of a non-floating node. - */ - if (is_irn_pinned_in_irg(node) && - is_Block_dead(get_nodes_block(skip_Proj(node)))) - return get_irg_bad(irg); + int irn_arity = get_irn_arity(node); + int i; for (i = 0; i < irn_arity; i++) { ir_node *pred = get_irn_n(node, i); - if (is_Bad(pred)) - return get_irg_bad(irg); -#if 0 - /* Propagating Unknowns here seems to be a bad idea, because - sometimes we need a node as a input and did not want that - it kills its user. - However, it might be useful to move this into a later phase - (if you think that optimizing such code is useful). */ - if (is_Unknown(pred) && mode_is_data(get_irn_mode(node))) - return new_r_Unknown(irg, get_irn_mode(node)); -#endif - } - } -#if 0 - /* With this code we violate the agreement that local_optimize - only leaves Bads in Block, Phi and Tuple nodes. */ - /* If Block has only Bads as predecessors it's garbage. */ - /* If Phi has only Bads as predecessors it's garbage. */ - if ((op == op_Block && get_Block_matured(node)) || op == op_Phi) { - irn_arity = get_irn_arity(node); - for (i = 0; i < irn_arity; i++) { - if (!is_Bad(get_irn_n(node, i))) break; + if (is_Bad(pred)) { + /* be careful not to kill cfopts too early or we might violate + * the 1 cfop per block property */ + if (!is_cfop(node) + || is_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK)) + return get_irg_bad(irg); + } } - if (i == irn_arity) node = get_irg_bad(irg); } -#endif + return node; -} /* gigo */ +} /** * These optimizations deallocate nodes from the obstack.