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 in the graph.
28 * @param irg The graph to be optimized. */
29 void local_optimize_graph (ir_graph *irg);
31 /** Performs dead node elimination by copying the ir graph to a new obstack.
33 * The major intention of this pass is to free memory occupied by
34 * dead nodes and outdated analyses information. Further this
35 * function removes Bad predecesors from Blocks and the corresponding
36 * inputs to Phi nodes. This opens optmization potential for other
37 * optimizations. Further this phase reduces dead Block<->Jmp
38 * self-cycles to Bad nodes.
40 * Dead_node_elimination is only performed if options `optimize' and
41 * `opt_dead_node_elimination' are set. The graph may
42 * not be in state phase_building. The outs datasturcture is freed,
43 * the outs state set to no_outs. Backedge information is conserved.
44 * Removes old attributes of nodes. Sets link field to NULL.
45 * Callee information must be freed (irg_callee_info_none).
47 * Attention: the numbers assigned to nodes if the library is compiled for
48 * development/debugging are not conserved by copying.
50 * @param irg The graph to be optimized. */
51 void dead_node_elimination(ir_graph *irg);
53 /** Cleans the control flow from Bad predecesors.
55 * Removes Bad predecesors from Blocks and the corresponding
56 * inputs to Phi nodes as in dead_node_elimination but without
59 * @param irg The graph to be optimized.
61 void remove_bad_predecessors(ir_graph *irg);
63 /** Inlines a method at the given call site.
65 * Removes the call node and splits the basic block the call node
66 * belongs to. Inserts a copy of the called graph between these nodes.
67 * Assumes that call is a Call node in current_ir_graph and that
68 * the type in the Call nodes type attribute is the same as the
69 * type of the called graph.
70 * Further it assumes that all Phi nodes in a block of current_ir_graph
71 * are assembled in a "link" list in the link field of the corresponding
72 * block nodes. Further assumes that all Proj nodes are in a "link" list
73 * in the nodes producing the tuple. (This is only an optical feature
74 * for the graph.) Conserves this feature for the old
75 * nodes of the graph. This precondition can be established by a call to
76 * collect_phisprojs(), see irgmod.h.
77 * As dead_node_elimination this function reduces dead Block<->Jmp
78 * self-cycles to Bad nodes.
80 * Called_graph must be unequal to current_ir_graph. Will not inline
82 * Sets visited masterflag in current_ir_graph to the max of the flag in
83 * current and called graph.
84 * Assumes that both, the called and the calling graph are in state
86 * It is recommended to call local_optimize_graph after inlining as this
87 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
88 * combination as control flow operation.
90 * @param call the call node that should be inlined
91 * @param called_graph the IR-graph that is called at call
93 * @return zero if method could not be inlined (recursion for instance),
94 * non-zero if all went ok
96 int inline_method(ir_node *call, ir_graph *called_graph);
98 /** Inlines all small methods at call sites where the called address comes
99 * from a Const node that references the entity representing the called
101 * The size argument is a rough measure for the code size of the method:
102 * Methods where the obstack containing the firm graph is smaller than
103 * size are inlined. Further only a limited number of calls are inlined.
104 * If the method contains more than 1024 inlineable calls none will be
106 * Inlining is only performed if flags `optimize' and `inlineing' are set.
107 * The graph may not be in state phase_building.
108 * It is recommended to call local_optimize_graph after inlining as this
109 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
110 * combination as control flow operation. */
111 void inline_small_irgs(ir_graph *irg, int size);
114 /** Inlineing with a different heuristic than inline_small_irgs.
116 * Inlines leave functions. If inlinening creates new leave
117 * function inlines these, too. (If g calls f, and f calls leave h,
118 * h is first inlined in f and then f in g.)
120 * Then inlines all small functions (this is not recursive).
122 * For a heuristic this inlineing uses firm node counts. It does
123 * not count auxiliary nodes as Proj, Tuple, End, Start, Id, Sync.
125 * @param maxsize Do not inline any calls if a method has more than
126 * maxsize firm nodes. It may reach this limit by
128 * @param leavesize Inline leave functions if they have less than leavesize
130 * @param size Inline all function smaller than size.
132 void inline_leave_functions(int maxsize, int leavesize, int size);
134 /** Code Placement. Pinns all floating nodes to a block where they
135 will be executed only if needed. Depends on the flag opt_global_cse.
136 Graph may not be in phase_building. Does not schedule control dead
137 code. Uses dominator information which it computes if the irg is not
138 in state dom_consistent. Destroys the out information as it moves nodes
139 to other blocks. Optimizes Tuples in Control edges.
140 @todo This is not tested!
142 Call remove_critical_cf_edges() before place_code(). This normalizes
143 the control flow graph so that for all operations a basic block exists
144 where they can be optimally placed.
146 @todo A more powerful code placement would move operations past Phi nodes
148 void place_code(ir_graph *irg);
150 /** Control flow optimization.
151 * Removes empty blocks doing if simplifications and loop simplifications.
152 * A block is empty if it contains only a Jmp node and Phi nodes.
153 * Merges single entry single exit blocks with their predecessor
154 * and propagates dead control flow by calling equivalent_node.
155 * Independent of compiler flag it removes Tuples from cf edges,
156 * Bad predecessors form blocks and unnecessary predecessors of End.
158 * @bug So far destroys backedge information.
159 * @bug Chokes on Id nodes if called in a certain order with other
160 * optimizations. Call local_optimize_graph before to remove
163 void optimize_cf(ir_graph *irg);
166 /** Places an empty basic block on critical control flow edges thereby
168 A critical control flow edge is an edge from a block with several
169 control exits to a block with several control entries (See Muchnic
171 Is only executed if flag set_opt_critical_edges() is set.
174 void remove_critical_cf_edges(ir_graph *irg);
176 # endif /* _IRGOPT_H_ */