2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Available Optimisations of libFirm.
25 #ifndef FIRM_IROPTIMIZE_H
26 #define FIRM_IROPTIMIZE_H
28 #include "firm_types.h"
31 * Control flow optimization.
33 * Removes empty blocks doing if simplifications and loop simplifications.
34 * A block is empty if it contains only a Jmp node and Phi nodes.
35 * Merges single entry single exit blocks with their predecessor
36 * and propagates dead control flow by calling equivalent_node().
37 * Independent of compiler flag it removes Tuples from cf edges,
38 * Bad predecessors from Blocks and Phis, and unnecessary predecessors of End.
40 * @bug So far destroys backedge information.
41 * @bug Chokes on Id nodes if called in a certain order with other
42 * optimizations. Call local_optimize_graph() before to remove
45 void optimize_cf(ir_graph *irg);
48 * Creates an ir_graph pass for optimize_cf().
50 * @param name the name of this pass or NULL
51 * @param verify should this pass be verified?
52 * @param dump should this pass result be dumped?
54 * @return the newly created ir_graph pass
56 ir_graph_pass_t *optimize_cf_pass(const char *name, int verify, int dump);
59 * Perform path-sensitive jump threading on the given graph.
61 * @param irg the graph
63 void opt_jumpthreading(ir_graph* irg);
66 * Creates an ir_graph pass for opt_jumpthreading().
68 * @param name the name of this pass or NULL
69 * @param verify should this pass be verified?
70 * @param dump should this pass result be dumped?
72 * @return the newly created ir_graph pass
74 ir_graph_pass_t *opt_jumpthreading_pass(const char *name, int verify, int dump);
77 * Try to simplify boolean expression in the given ir graph.
78 * eg. x < 5 && x < 6 becomes x < 5
80 * @param irg the graph
82 void opt_bool(ir_graph *irg);
85 * Creates an ir_graph pass for opt_bool().
87 * @param name the name of this pass or NULL
88 * @param verify should this pass be verified?
89 * @param dump should this pass result be dumped?
91 * @return the newly created ir_graph pass
93 ir_graph_pass_t *opt_bool_pass(const char *name, int verify, int dump);
96 * Try to reduce the number of conv nodes in the given ir graph.
98 * @param irg the graph
100 * @return non-zero if the optimization could be applied, 0 else
102 int conv_opt(ir_graph *irg);
105 * Creates an ir_graph pass for conv_opt().
107 * @param name the name of this pass or NULL
108 * @param verify should this pass be verified?
109 * @param dump should this pass result be dumped?
111 * @return the newly created ir_graph pass
113 ir_graph_pass_t *conv_opt_pass(const char *name, int verify, int dump);
116 * Do the scalar replacement optimization.
117 * Make a date flow analyze and split the
120 * @param irg the graph which should be optimized
122 void data_flow_scalar_replacement_opt(ir_graph *irg);
125 * A callback that checks whether a entity is an allocation
128 typedef int (*check_alloc_entity_func)(ir_entity *ent);
131 * Do simple and fast escape analysis for one graph.
133 * @param irg the graph
134 * @param callback a callback function to check whether a
135 * given entity is a allocation call
137 void escape_enalysis_irg(ir_graph *irg, check_alloc_entity_func callback);
140 * Do simple and fast escape analysis for all graphs.
142 * This optimization implements a simple and fast but inexact
143 * escape analysis. Some addresses might be marked as 'escaped' even
145 * The advantage is a low memory footprint and fast speed.
147 * @param run_scalar_replace if this flag in non-zero, scalar
148 * replacement optimization is run on graphs with removed
150 * @param callback a callback function to check whether a
151 * given entity is a allocation call
153 * This optimization removes allocation which are not used (rare) and replace
154 * allocation that can be proved dead at the end of the graph which stack variables.
156 * The creation of stack variable allows scalar replacement to be run only
157 * on those graphs that have been changed.
159 * This is most effective on Java where no other stack variables exists.
161 void escape_analysis(int run_scalar_replace, check_alloc_entity_func callback);
164 * Optimize function calls by handling const functions.
166 * This optimization first detects all "const functions", i.e.,
167 * IR graphs that neither read nor write memory (and hence did
168 * not create exceptions, as these use memory in Firm).
170 * The result of calls to such functions depends only on its
171 * arguments, hence those calls are no more pinned.
173 * This is a rather strong criteria, so do not expect that a
174 * lot of functions will be found. Moreover, all of them might
175 * already be inlined if inlining is activated.
176 * Anyway, it might be good for handling builtin's or pseudo-graphs,
177 * even if the later read/write memory (but we know how).
179 * This optimizations read the irg_const_function property of
180 * entities and and sets the irg_const_function property of
183 * If callee information is valid, we also optimize polymorphic Calls.
185 * @param force_run if non-zero, an optimization run is started even
186 * if no const function graph was detected.
187 * Else calls are only optimized if at least one
188 * const function graph was detected.
189 * @param callback a callback function to check whether a
190 * given entity is a allocation call
192 * If the frontend created external entities with the irg_const_function
193 * property set, the force_run parameter should be set, else
196 * @note This optimization destroys the link fields of nodes.
198 void optimize_funccalls(int force_run, check_alloc_entity_func callback);
201 * Creates an ir_prog pass for optimize_funccalls().
203 * @param name the name of this pass or NULL
204 * @param verify should this pass be verified?
205 * @param dump should this pass result be dumped?
206 * @param force_run if non-zero, an optimization run is started even
207 * if no const function graph was detected.
208 * Else calls are only optimized if at least one
209 * const function graph was detected.
210 * @param callback a callback function to check whether a
211 * given entity is a allocation call
213 * @return the newly created ir_prog pass
215 ir_prog_pass_t *optimize_funccalls_pass(
216 const char *name, int verify, int dump,
217 int force_run, check_alloc_entity_func callback);
220 * Does Partial Redundancy Elimination combined with
221 * Global Value Numbering.
222 * Can be used to replace place_code() completely.
224 * Based on VanDrunen and Hosking 2004.
226 * @param irg the graph
228 void do_gvn_pre(ir_graph *irg);
231 * Creates an ir_graph pass for do_gvn_pre().
233 * @param name the name of this pass or NULL
234 * @param verify should this pass be verified?
235 * @param dump should this pass result be dumped?
237 * @return the newly created ir_graph pass
239 ir_graph_pass_t *do_gvn_pre_pass(const char *name, int verify, int dump);
242 * This function is called to evaluate, if a mux can build
243 * of the current architecture.
244 * If it returns non-zero, a mux is created, else the code
246 * @param sel A selector of a Cond.
247 * @param phi_list List of Phi nodes about to be converted (linked via get_Phi_next() field)
248 * @param i First data predecessor involved in if conversion
249 * @param j Second data predecessor involved in if conversion
251 typedef int (*arch_allow_ifconv_func)(ir_node *sel, ir_node* phi_list, int i, int j);
254 * The parameters structure.
256 struct ir_settings_if_conv_t {
257 int max_depth; /**< The maximum depth up to which expressions
258 are examined when it has to be decided if they
259 can be placed into another block. */
260 arch_allow_ifconv_func allow_ifconv; /**< Evaluator function, if not set all possible Psi
261 nodes will be created. */
265 * Perform If conversion on a graph.
267 * @param irg The graph.
268 * @param params The parameters for the if conversion.
270 * Cannot handle blocks with Bad control predecessors, so call it after control
273 void opt_if_conv(ir_graph *irg, const ir_settings_if_conv_t *params);
276 * Creates an ir_graph pass for opt_if_conv().
278 * @param name the name of this pass or NULL
279 * @param verify should this pass be verified?
280 * @param dump should this pass result be dumped?
281 * @param params The parameters for the if conversion.
283 * @return the newly created ir_graph pass
285 ir_graph_pass_t *opt_if_conv_pass(
286 const char *name, int verify, int dump, const ir_settings_if_conv_t *params);
288 void opt_sync(ir_graph *irg);
291 * Creates an ir_graph pass for opt_sync().
293 * @param name the name of this pass or NULL
294 * @param verify should this pass be verified?
295 * @param dump should this pass result be dumped?
297 * @return the newly created ir_graph pass
299 ir_graph_pass_t *opt_sync_pass(const char *name, int verify, int dump);
302 * Check if we can replace the load by a given const from
303 * the const code irg.
305 * @param load the load to replace
306 * @param c the constant
308 * @return in the modes match or can be transformed using a reinterpret cast
309 * returns a copy of the constant (possibly Conv'ed) on the
312 ir_node *can_replace_load_by_const(const ir_node *load, ir_node *c);
315 * Load/Store optimization.
317 * Removes redundant non-volatile Loads and Stores.
318 * May introduce Bad nodes if exceptional control flow
319 * is removed. The following cases are optimized:
321 * Load without result: A Load which has only a memory use
324 * Load after Store: A Load after a Store is removed, if
325 * the Load doesn't have an exception handler OR is in
326 * the same block as the Store.
328 * Load after Load: A Load after a Load is removed, if the
329 * Load doesn't have an exception handler OR is in the
330 * same block as the previous Load.
332 * Store before Store: A Store immediately before another
333 * Store in the same block is removed, if the Store doesn't
334 * have an exception handler.
336 * Store after Load: A Store after a Load is removed, if the
337 * Store doesn't have an exception handler.
339 * @return non-zero if the optimization could be applied, 0 else
341 int optimize_load_store(ir_graph *irg);
344 * Creates an ir_graph pass for optimize_load_store().
346 * @param name the name of this pass or NULL
347 * @param verify should this pass be verified?
348 * @param dump should this pass result be dumped?
350 * @return the newly created ir_graph pass
352 ir_graph_pass_t *optimize_load_store_pass(const char *name, int verify, int dump);
355 * New experimental alternative to optimize_load_store.
356 * Based on a dataflow analysis, so load/stores are moved out of loops
359 int opt_ldst(ir_graph *irg);
362 * Creates an ir_graph pass for opt_ldst().
364 * @param name the name of this pass or NULL
365 * @param verify should this pass be verified?
366 * @param dump should this pass result be dumped?
368 * @return the newly created ir_graph pass
370 ir_graph_pass_t *opt_ldst_pass(const char *name, int verify, int dump);
373 * Do Loop unrolling in the given graph.
375 void optimize_loop_unrolling(ir_graph *irg);
378 * Creates an ir_graph pass for optimize_loop_unrolling().
380 * @param name the name of this pass or NULL
381 * @param verify should this pass be verified?
382 * @param dump should this pass result be dumped?
384 * @return the newly created ir_graph pass
386 ir_graph_pass_t *optimize_loop_unrolling_pass(const char *name, int verify, int dump);
389 * Optimize the frame type of an irg by removing
390 * never touched entities.
392 * @param irg The graph whose frame type will be optimized
394 * This function did not change the graph, only it's frame type.
395 * The layout state of the frame type will be set to layout_undefined
396 * if entities were removed.
398 void opt_frame_irg(ir_graph *irg);
401 * Creates an ir_graph pass for opt_frame_irg().
403 * @param name the name of this pass or NULL
404 * @param verify should this pass be verified?
405 * @param dump should this pass result be dumped?
407 * @return the newly created ir_graph pass
409 ir_graph_pass_t *opt_frame_irg_pass(const char *name, int verify, int dump);
411 /** Possible flags for the Operator Scalar Replacement. */
412 typedef enum osr_flags {
413 osr_flag_none = 0, /**< no additional flags */
414 osr_flag_lftr_with_ov_check = 1, /**< do linear function test replacement
415 only if no overflow can occur. */
416 osr_flag_ignore_x86_shift = 2, /**< ignore Multiplications by 2, 4, 8 */
417 osr_flag_keep_reg_pressure = 4 /**< do NOT increase register pressure by introducing new
418 induction variables. */
421 /* FirmJNI cannot handle identical enum values... */
423 /** default setting */
424 #define osr_flag_default osr_flag_lftr_with_ov_check
427 * Do the Operator Scalar Replacement optimization and linear
428 * function test replacement for loop control.
429 * Can be switched off using the set_opt_strength_red() flag.
430 * In that case, only remove_phi_cycles() is executed.
432 * @param irg the graph which should be optimized
433 * @param flags set of osr_flags
435 * The linear function replacement test is controlled by the flags.
436 * If the osr_flag_lftr_with_ov_check is set, the replacement is only
437 * done if do overflow can occur.
438 * Otherwise it is ALWAYS done which might be insecure.
442 * for (i = 0; i < 100; ++i)
444 * might be replaced by
446 * for (i = 0; i < 400; i += 4)
450 * for (i = 0; i < 0x7FFFFFFF; ++i)
452 * will not be replaced by
454 * for (i = 0; i < 0xFFFFFFFC; i += 4)
456 * because of overflow.
460 * for (i = 0; i <= 0xF; ++i)
462 * will NOT be transformed into
464 * for (i = 0xFFFFFFF0; i <= 0xFFFFFFFF; ++i)
466 * although here is no direct overflow. The OV occurs when the ++i
467 * is executed (and would created an endless loop here!).
469 * For the same reason, a loop
471 * for (i = 0; i <= 9; i += x)
473 * will NOT be transformed because we cannot estimate whether an overflow
474 * might happen adding x.
476 * Note that i < a + 400 is also not possible with the current implementation
477 * although this might be allowed by other compilers...
479 * Note further that tests for equality can be handled some simpler (but are not
482 * This algorithm destroys the link field of nodes.
484 void opt_osr(ir_graph *irg, unsigned flags);
487 * Creates an ir_graph pass for remove_phi_cycles().
489 * @param name the name of this pass or NULL
490 * @param verify should this pass be verified?
491 * @param dump should this pass result be dumped?
492 * @param flags set of osr_flags
494 * @return the newly created ir_graph pass
496 ir_graph_pass_t *opt_osr_pass(const char *name, int verify, int dump, unsigned flags);
499 * Removes useless Phi cycles, i.e cycles of Phi nodes with only one
501 * This is automatically done in opt_osr(), so there is no need to call it
504 * @param irg the graph which should be optimized
506 * This algorithm destroys the link field of nodes.
508 void remove_phi_cycles(ir_graph *irg);
511 * Creates an ir_graph pass for remove_phi_cycles().
513 * @param name the name of this pass or NULL
514 * @param verify should this pass be verified?
515 * @param dump should this pass result be dumped?
516 * @param params The parameters for the if conversion.
518 * @return the newly created ir_graph pass
520 ir_graph_pass_t *remove_phi_cycles_pass(const char *name, int verify, int dump);
523 /** A default threshold. */
524 #define DEFAULT_CLONE_THRESHOLD 300
527 * Do procedure cloning. Evaluate a heuristic weight for every
528 * Call(..., Const, ...). If the weight is bigger than threshold,
529 * clone the entity and fix the calls.
531 * @param threshold the threshold for cloning
533 * The threshold is an estimation of how many instructions are saved
534 * when executing a cloned method. If threshold is 0.0, every possible
537 void proc_cloning(float threshold);
542 * Applies Reassociation rules to integer expressions.
543 * Beware: Works only if integer overflow might be ignored, as for C, Java
544 * and for address expression.
545 * Works only if Constant folding is activated.
547 * Uses loop information to detect loop-invariant (ie contant
548 * inside the loop) values.
550 * See Muchnik 12.3.1 Algebraic Simplification and Reassociation of
551 * Addressing Expressions.
553 * @return non-zero if the optimization could be applied, 0 else
555 int optimize_reassociation(ir_graph *irg);
558 * Creates an ir_graph pass for optimize_reassociation().
560 * @param name the name of this pass or NULL
561 * @param verify should this pass be verified?
562 * @param dump should this pass result be dumped?
564 * @return the newly created ir_graph pass
566 ir_graph_pass_t *optimize_reassociation_pass(const char *name, int verify, int dump);
569 * Normalize the Returns of a graph by creating a new End block
570 * with One Return(Phi).
571 * This is the preferred input for the if-conversion.
573 * In pseudocode, it means:
580 * is transformed into
588 void normalize_one_return(ir_graph *irg);
591 * Creates an ir_graph pass for normalize_one_return().
593 * @param name the name of this pass or NULL
594 * @param verify should this pass be verified?
595 * @param dump should this pass result be dumped?
597 * @return the newly created ir_graph pass
599 ir_graph_pass_t *normalize_one_return_pass(const char *name, int verify, int dump);
602 * Normalize the Returns of a graph by moving
603 * the Returns upwards as much as possible.
604 * This might be preferred for code generation.
606 * In pseudocode, it means:
614 * is transformed into
621 void normalize_n_returns(ir_graph *irg);
624 * Creates an ir_graph pass for normalize_n_returns().
626 * @param name the name of this pass or NULL
627 * @param verify should this pass be verified?
628 * @param dump should this pass result be dumped?
630 * @return the newly created ir_graph pass
632 ir_graph_pass_t *normalize_n_returns_pass(const char *name, int verify, int dump);
635 * Do the scalar replacement optimization.
636 * Replace local compound entities (like structures and arrays)
637 * with atomic values if possible. Does not handle classes yet.
639 * @param irg the graph which should be optimized
641 * @return non-zero, if at least one entity was replaced
643 int scalar_replacement_opt(ir_graph *irg);
646 * Creates an ir_graph pass for scalar_replacement_opt().
648 * @param name the name of this pass or NULL
649 * @param verify should this pass be verified?
650 * @param dump should this pass result be dumped?
652 * @return the newly created ir_graph pass
654 ir_graph_pass_t *scalar_replacement_opt_pass(const char *name, int verify, int dump);
656 /** Performs strength reduction for the passed graph. */
657 void reduce_strength(ir_graph *irg);
660 * Optimizes tail-recursion calls by converting them into loops.
661 * Depends on the flag opt_tail_recursion.
662 * Currently supports the following forms:
664 * - return x + func();
665 * - return func() - x;
666 * - return x * func();
669 * Does not work for Calls that use the exception stuff.
671 * @param irg the graph to be optimized
673 * @return non-zero if the optimization could be applied, 0 else
675 int opt_tail_rec_irg(ir_graph *irg);
678 * Creates an ir_graph pass for opt_tail_rec_irg().
680 * @param name the name of this pass or NULL
681 * @param verify should this pass be verified?
682 * @param dump should this pass result be dumped?
684 * @return the newly created ir_graph pass
686 ir_graph_pass_t *opt_tail_rec_irg_pass(const char *name, int verify, int dump);
689 * Optimize tail-recursion calls for all IR-Graphs.
690 * Can currently handle:
691 * - direct return value, i.e. return func().
692 * - additive return value, i.e. return x +/- func()
693 * - multiplicative return value, i.e. return x * func() or return -func()
695 * The current implementation must be run before optimize_funccalls(),
696 * because it expects the memory edges pointing to calls, which might be
697 * removed by optimize_funccalls().
699 void opt_tail_recursion(void);
702 * Creates an ir_prog pass for opt_tail_recursion().
704 * @param name the name of this pass or NULL
705 * @param verify should this pass be verified?
706 * @param dump should this pass result be dumped?
708 * @return the newly created ir_prog pass
710 ir_prog_pass_t *opt_tail_recursion_pass(const char *name, int verify, int dump);
712 /** This is the type for a method, that returns a pointer type to
713 * tp. This is needed in the normalization. */
714 typedef ir_type *(*gen_pointer_type_to_func)(ir_type *tp);
716 /** Insert Casts so that class type casts conform exactly with the type hierarchy.
718 * Formulated in Java, this achieves the following:
720 * For a class hierarchy
722 * class B extends A {}
723 * class C extends B {}
724 * we transforms a cast
729 * The algorithm works for Casts with class types, but also for Casts
730 * with all pointer types that point (over several indirections,
731 * i.e. ***A) to a class type. Normalizes all graphs. Computes type
732 * information (@see irtypeinfo.h) if not available.
733 * Invalidates trout information as new casts are generated.
735 * @param gppt_fct A function that returns a pointer type that points
736 * to the type given as argument. If this parameter is NULL, a default
737 * function is used that either uses trout information or performs a O(n)
738 * search to find an existing pointer type. If it can not find a type,
739 * generates a pointer type with mode_P_mach and suffix "cc_ptr_tp".
741 void normalize_irp_class_casts(gen_pointer_type_to_func gppt_fct);
743 /** Insert Casts so that class type casts conform exactly with the type hierarchy
746 * For more details see normalize_irp_class_casts().
748 * This transformation requires that type information is computed. @see irtypeinfo.h.
750 void normalize_irg_class_casts(ir_graph *irg, gen_pointer_type_to_func gppt_fct);
752 /** Optimize casting between class types.
755 * class B extends A { }
756 * class C extends B {}
757 * Performs the following transformations:
758 * C c = (C)(B)(A)(B)new C() --> C c = (C)(B)newC() --> C c = new C()
759 * (Optimizing downcasts as A a = (A)(B)(new A()) --> A a = new A() can
760 * be suppressed by setting the flag opt_suppress_downcast_optimization.
761 * Downcasting A to B might cause an exception. It is not clear
762 * whether this is modeled by the Firm Cast node, as it has no exception
764 * If there is inh_m() that overwrites m() in B:
765 * ((A) new B()).m() --> (new B()).inh_m()
766 * Phi((A)x, (A)y) --> (A) Phi (x, y) if (A) is an upcast.
768 * Computes type information if not available. @see irtypeinfo.h.
769 * Typeinformation is valid after optimization.
770 * Invalidates trout information.
772 void optimize_class_casts(void);
775 * CLiff Click's combo algorithm from "Combining Analyses, combining Optimizations".
777 * Does conditional constant propagation, unreachable code elimination and optimistic
778 * global value numbering at once.
780 * @param irg the graph to run on
782 void combo(ir_graph *irg);
785 * Creates an ir_graph pass for combo.
787 * @param name the name of this pass or NULL
788 * @param verify should this pass be verified?
789 * @param dump should this pass result be dumped?
791 * @return the newly created ir_graph pass
793 ir_graph_pass_t *combo_pass(const char *name, int verify, int dump);
795 /** Inlines all small methods at call sites where the called address comes
796 * from a SymConst node that references the entity representing the called
799 * The size argument is a rough measure for the code size of the method:
800 * Methods where the obstack containing the firm graph is smaller than
801 * size are inlined. Further only a limited number of calls are inlined.
802 * If the method contains more than 1024 inlineable calls none will be
804 * Inlining is only performed if flags `optimize' and `inlineing' are set.
805 * The graph may not be in state phase_building.
806 * It is recommended to call local_optimize_graph() after inlining as this
807 * function leaves a set of obscure Tuple nodes, e.g. a Proj-Tuple-Jmp
808 * combination as control flow operation.
810 void inline_small_irgs(ir_graph *irg, int size);
813 /** Inlineing with a different heuristic than inline_small_irgs().
815 * Inlines leave functions. If inlinening creates new leave
816 * function inlines these, too. (If g calls f, and f calls leave h,
817 * h is first inlined in f and then f in g.)
819 * Then inlines all small functions (this is not recursive).
821 * For a heuristic this inlineing uses firm node counts. It does
822 * not count auxiliary nodes as Proj, Tuple, End, Start, Id, Sync.
823 * If the ignore_runtime flag is set, calls to functions marked with the
824 * mtp_property_runtime property are ignored.
826 * @param maxsize Do not inline any calls if a method has more than
827 * maxsize firm nodes. It may reach this limit by
829 * @param leavesize Inline leave functions if they have less than leavesize
831 * @param size Inline all function smaller than size.
832 * @param ignore_runtime count a function only calling runtime functions as
835 void inline_leave_functions(unsigned maxsize, unsigned leavesize,
836 unsigned size, int ignore_runtime);
839 * Heuristic inliner. Calculates a benefice value for every call and inlines
840 * those calls with a value higher than the threshold.
842 * @param maxsize Do not inline any calls if a method has more than
843 * maxsize firm nodes. It may reach this limit by
845 * @param threshold inlining threshold
847 void inline_functions(unsigned maxsize, int inline_threshold);
850 * Combines congruent blocks into one.
852 * @param irg The IR-graph to optimize.
854 * @return non-zero if the graph was transformed
856 int shape_blocks(ir_graph *irg);