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22 * @brief Optimizations for a whole ir graph, i.e., a procedure.
23 * @author Christian Schaefer, Goetz Lindenmaier, Sebastian Felis
26 #ifndef FIRM_IR_IRGOPT_H
27 #define FIRM_IR_IRGOPT_H
29 #include "firm_types.h"
31 /** Applies local optimizations (see iropt.h) to all nodes reachable from node n.
33 * @param n The node to be optimized.
35 void local_optimize_node(ir_node *n);
37 /** Applies local optimizations (see iropt.h) to all nodes in the graph.
39 * @param irg The graph to be optimized.
41 * After applying local_optimize_graph() to a IR-graph, Bad nodes
42 * only occur as predecessor of Block and Phi nodes.
44 void local_optimize_graph(ir_graph *irg);
46 /** Applies local optimizations (see iropt.h) to all nodes in the graph.
48 * After applying optimize_graph_df() to a IR-graph, Bad nodes
49 * only occur as predecessor of Block and Phi nodes.
51 * This version uses fixpoint iteration.
53 * @param irg The graph to be optimized.
55 * @return non-zero if the optimization could be applied, 0 else
57 int optimize_graph_df(ir_graph *irg);
60 * Creates an ir_graph pass for optimize_graph_df().
62 * @param name the name of this pass or NULL
63 * @param verify should this pass be verified?
64 * @param dump should this pass result be dumped?
66 * @return the newly created ir_graph pass
68 ir_graph_pass_t *optimize_graph_df_pass(const char *name);
70 /** Performs dead node elimination by copying the ir graph to a new obstack.
72 * The major intention of this pass is to free memory occupied by
73 * dead nodes and outdated analyzes information. Further this
74 * function removes Bad predecessors from Blocks and the corresponding
75 * inputs to Phi nodes. This opens optimization potential for other
76 * optimizations. Further this phase reduces dead Block<->Jmp
77 * self-cycles to Bad nodes.
79 * Dead_node_elimination is only performed if options `optimize' and
80 * `opt_dead_node_elimination' are set. The graph may
81 * not be in state phase_building. The outs datasturcture is freed,
82 * the outs state set to outs_none. Backedge information is conserved.
83 * Removes old attributes of nodes. Sets link field to NULL.
84 * Callee information must be freed (irg_callee_info_none).
86 * @param irg The graph to be optimized.
88 void dead_node_elimination(ir_graph *irg);
90 typedef struct _survive_dce_t survive_dce_t;
93 * Make a new Survive DCE environment.
95 survive_dce_t *new_survive_dce(void);
98 * Free a Survive DCE environment.
100 void free_survive_dce(survive_dce_t *sd);
103 * Register a node pointer to be patched upon DCE.
104 * When DCE occurs, the node pointer specified by @p place will be
105 * patched to the new address of the node it is pointing to.
107 * @param sd The Survive DCE environment.
108 * @param place The address of the node pointer.
110 void survive_dce_register_irn(survive_dce_t *sd, ir_node **place);
112 /** Cleans the control flow from Bad predecessors.
114 * Removes Bad predecessors from Blocks and the corresponding
115 * inputs to Phi nodes as in dead_node_elimination but without
118 * Conserves loop information.
120 * @param irg The graph to be optimized.
122 void remove_bad_predecessors(ir_graph *irg);
124 /** Inlines a method at the given call site.
126 * Removes the call node and splits the basic block the call node
127 * belongs to. Inserts a copy of the called graph between these nodes.
128 * Assumes that call is a Call node in current_ir_graph and that
129 * the type in the Call nodes type attribute is the same as the
130 * type of the called graph.
131 * Further it assumes that all Phi nodes in a block of current_ir_graph
132 * are assembled in a "link" list in the link field of the corresponding
133 * block nodes. Further assumes that all Proj nodes are in a "link" list
134 * in the nodes producing the tuple. (This is only an optical feature
135 * for the graph.) Conserves this feature for the old
136 * nodes of the graph. This precondition can be established by a call to
137 * collect_phisprojs(), see irgmod.h.
138 * As dead_node_elimination this function reduces dead Block<->Jmp
139 * self-cycles to Bad nodes.
141 * Called_graph must be unequal to current_ir_graph. Will not inline
143 * Sets visited masterflag in current_ir_graph to the max of the flag in
144 * current and called graph.
145 * Assumes that both, the called and the calling graph are in state
146 * "op_pin_state_pinned".
147 * It is recommended to call local_optimize_graph() after inlining as this
148 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
149 * combination as control flow operation.
151 * @param call the call node that should be inlined
152 * @param called_graph the IR-graph that is called at call
154 * @return zero if method could not be inlined (recursion for instance),
155 * non-zero if all went ok
157 int inline_method(ir_node *call, ir_graph *called_graph);
161 * Pins all floating nodes to a block where they
162 * will be executed only if needed. Depends on the flag opt_global_cse.
163 * Graph may not be in phase_building. Does not schedule control dead
164 * code. Uses dominator information which it computes if the irg is not
165 * in state dom_consistent. Destroys the out information as it moves nodes
166 * to other blocks. Optimizes Tuples in Control edges.
167 * @todo This is not tested!
169 * Call remove_critical_cf_edges() before place_code(). This normalizes
170 * the control flow graph so that for all operations a basic block exists
171 * where they can be optimally placed.
173 * @todo A more powerful code placement would move operations past Phi nodes
176 void place_code(ir_graph *irg);
179 * Creates an ir_graph pass for place_code().
180 * This pass enables GCSE, runs optimize_graph_df() and finally
183 * @param name the name of this pass or NULL
185 * @return the newly created ir_graph pass
187 ir_graph_pass_t *place_code_pass(const char *name);
189 /** Places an empty basic block on critical control flow edges thereby
192 * A critical control flow edge is an edge from a block with several
193 * control exits to a block with several control entries (See Muchnic
194 * p. 407). Exception edges are always ignored.
196 * @param irg IR Graph
198 void remove_critical_cf_edges(ir_graph *irg);
200 /** Places an empty basic block on critical control flow edges thereby
203 * A critical control flow edge is an edge from a block with several
204 * control exits to a block with several control entries (See Muchnic
207 * @param irg IR Graph
208 * @param ignore_exception_edges if non-zero, exception edges will be ignored
210 void remove_critical_cf_edges_ex(ir_graph *irg, int ignore_exception_edges);