3 * File name: ir/ir/irgopt.h
4 * Purpose: Optimizations for a whole ir graph, i.e., a procedure.
5 * Author: Christian Schaefer, Goetz Lindenmaier
6 * Modified by: Sebastian Felis
9 * Copyright: (c) 1998-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 * Optimizations for a whole ir graph, i.e., a procedure.
18 * @author Christian Schaefer, Goetz Lindenmaier
26 /** Applies local optimizations (see iropt.h) to all nodes reachable from node n.
28 * @param n The node to be optimized.
30 void local_optimize_node(ir_node *n);
32 /** Applies local optimizations (see iropt.h) to all nodes in the graph.
34 * @param irg The graph to be optimized.
36 * After applying local_optimize_graph() to a IR-graph, Bad nodes
37 * only occure as predecessor of Block and Phi nodes.
39 void local_optimize_graph (ir_graph *irg);
41 /** Performs dead node elimination by copying the ir graph to a new obstack.
43 * The major intention of this pass is to free memory occupied by
44 * dead nodes and outdated analyses information. Further this
45 * function removes Bad predecesors from Blocks and the corresponding
46 * inputs to Phi nodes. This opens optmization potential for other
47 * optimizations. Further this phase reduces dead Block<->Jmp
48 * self-cycles to Bad nodes.
50 * Dead_node_elimination is only performed if options `optimize' and
51 * `opt_dead_node_elimination' are set. The graph may
52 * not be in state phase_building. The outs datasturcture is freed,
53 * the outs state set to outs_none. Backedge information is conserved.
54 * Removes old attributes of nodes. Sets link field to NULL.
55 * Callee information must be freed (irg_callee_info_none).
57 * @param irg The graph to be optimized.
59 void dead_node_elimination(ir_graph *irg);
61 typedef struct _survive_dce_t survive_dce_t;
64 * Make a new Survive DCE environment.
66 survive_dce_t *new_survive_dce(void);
69 * Free a Survive DCE environment.
71 void free_survive_dce(survive_dce_t *sd);
74 * Register a node pointer to be patched upon DCE.
75 * When DCE occurs, the node pointer specified by @p place will be
76 * patched to the new address of the node it is pointing to.
78 * @param sd The Survive DCE environment.
79 * @param place The address of the node pointer.
81 void survive_dce_register_irn(survive_dce_t *sd, ir_node **place);
83 /** Cleans the control flow from Bad predecesors.
85 * Removes Bad predecesors from Blocks and the corresponding
86 * inputs to Phi nodes as in dead_node_elimination but without
89 * Conserves loop information.
91 * @param irg The graph to be optimized.
93 void remove_bad_predecessors(ir_graph *irg);
95 /** Inlines a method at the given call site.
97 * Removes the call node and splits the basic block the call node
98 * belongs to. Inserts a copy of the called graph between these nodes.
99 * Assumes that call is a Call node in current_ir_graph and that
100 * the type in the Call nodes type attribute is the same as the
101 * type of the called graph.
102 * Further it assumes that all Phi nodes in a block of current_ir_graph
103 * are assembled in a "link" list in the link field of the corresponding
104 * block nodes. Further assumes that all Proj nodes are in a "link" list
105 * in the nodes producing the tuple. (This is only an optical feature
106 * for the graph.) Conserves this feature for the old
107 * nodes of the graph. This precondition can be established by a call to
108 * collect_phisprojs(), see irgmod.h.
109 * As dead_node_elimination this function reduces dead Block<->Jmp
110 * self-cycles to Bad nodes.
112 * Called_graph must be unequal to current_ir_graph. Will not inline
114 * Sets visited masterflag in current_ir_graph to the max of the flag in
115 * current and called graph.
116 * Assumes that both, the called and the calling graph are in state
117 * "op_pin_state_pinned".
118 * It is recommended to call local_optimize_graph() after inlining as this
119 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
120 * combination as control flow operation.
122 * @param call the call node that should be inlined
123 * @param called_graph the IR-graph that is called at call
125 * @return zero if method could not be inlined (recursion for instance),
126 * non-zero if all went ok
128 int inline_method(ir_node *call, ir_graph *called_graph);
130 /** Inlines all small methods at call sites where the called address comes
131 * from a SymConst node that references the entity representing the called
134 * The size argument is a rough measure for the code size of the method:
135 * Methods where the obstack containing the firm graph is smaller than
136 * size are inlined. Further only a limited number of calls are inlined.
137 * If the method contains more than 1024 inlineable calls none will be
139 * Inlining is only performed if flags `optimize' and `inlineing' are set.
140 * The graph may not be in state phase_building.
141 * It is recommended to call local_optimize_graph() after inlining as this
142 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
143 * combination as control flow operation.
145 void inline_small_irgs(ir_graph *irg, int size);
148 /** Inlineing with a different heuristic than inline_small_irgs().
150 * Inlines leave functions. If inlinening creates new leave
151 * function inlines these, too. (If g calls f, and f calls leave h,
152 * h is first inlined in f and then f in g.)
154 * Then inlines all small functions (this is not recursive).
156 * For a heuristic this inlineing uses firm node counts. It does
157 * not count auxiliary nodes as Proj, Tuple, End, Start, Id, Sync.
159 * @param maxsize Do not inline any calls if a method has more than
160 * maxsize firm nodes. It may reach this limit by
162 * @param leavesize Inline leave functions if they have less than leavesize
164 * @param size Inline all function smaller than size.
166 void inline_leave_functions(int maxsize, int leavesize, int size);
170 * Pins all floating nodes to a block where they
171 * will be executed only if needed. Depends on the flag opt_global_cse.
172 * Graph may not be in phase_building. Does not schedule control dead
173 * code. Uses dominator information which it computes if the irg is not
174 * in state dom_consistent. Destroys the out information as it moves nodes
175 * to other blocks. Optimizes Tuples in Control edges.
176 * @todo This is not tested!
178 * Call remove_critical_cf_edges() before place_code(). This normalizes
179 * the control flow graph so that for all operations a basic block exists
180 * where they can be optimally placed.
182 * @todo A more powerful code placement would move operations past Phi nodes
185 void place_code(ir_graph *irg);
187 /** Places an empty basic block on critical control flow edges thereby
190 * A critical control flow edge is an edge from a block with several
191 * control exits to a block with several control entries (See Muchnic
194 * @param irg IR Graph
196 void remove_critical_cf_edges(ir_graph *irg);
198 # endif /* _IRGOPT_H_ */