3 * File name: ir/ir/irflag.h
4 * Purpose: Flags to control optimizations.
5 * Author: Christian Schaefer, Goetz Lindenmaier
6 * Modified by: Michael Beck
9 * Copyright: (c) 1999-2003 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
16 * Flags to customize the behavior of libfirm.
18 * @author Christian Schaefer
20 * There are the following groups of flags:
21 * 1. Optimization flags.
22 * a) There is a flag, 'optimize' to turn on/off all optimizations.
23 * b) There are flags for each individual optimization. Some flags turns
24 * transformations in several algorithms on/off.
25 * 2. Normalization flags.
26 * These flags steer transformations of the ir that improve it, as removing
27 * dump Phi nodes (one predecessor, all preds are equal ...), Ids, Tuples ...
29 * a) Flags to steer the level of the information.
30 * b) Flags to steer in which phase information should be dumped.
31 * 4. Verification flag
32 * This one controls the behavior of node and type verifications
37 #include "firm_types.h"
40 * A container type to load/restore all optimizations
42 typedef unsigned optimization_state_t;
45 * This function enables/disables optimizations globally.
47 * If optimize == 0 no optimizations are performed at all.
48 * Default: optimize == 1.
50 void set_optimize (int value);
51 int get_optimize(void);
53 /** This function enables/disables output of information about phases and
54 * controls the verbosity level.
56 * 0: no output at all.
57 * 1: very short output
58 * >>1: very verbose output.
60 void set_firm_verbosity (int value);
61 int get_firm_verbosity (void);
63 /** Enables/Disables constant folding optimization.
65 * If opt_constant_folding == 1 perform
66 * - constant expression evaluation (2 + 5 ==> 7, 3 < 2 ==> false)
67 * - algebraic simplification (a * 0 ==> 0, a or a ==> a)
68 * - simplification of tests ( !(a < b) ==> (a >= b))
69 * - refining the memory representation
70 * - remove store after load
71 * Default: opt_constant_folding == 1.
73 void set_opt_constant_folding (int value);
75 /** Enables/Disables loop unrolling.
77 * If opt_loop_unrolling == 1 perform loop_unrolling.
78 * See loop_unrolling.h.
80 * Default: opt_loop_unrolling = 1;
82 void set_opt_loop_unrolling (int value);
84 /** Enables/Disables output of information about loop unrolling.
86 void set_opt_loop_unrolling_verbose (int value);
88 /** Enables/Disables removal of redundant Loads and Stores.
90 * - Remove Store that overwrites a just stored value (WAW).
91 * - Remove Store if it stores a value just loaded (WAR with the same value).
92 * - Remove Load that loads a value just saved (RAW with the same value).
93 * - remove Load that loads a value already loaded (RAR)
94 * - replace Load of constant values with constants (RC)
96 void set_opt_redundant_loadstore(int value);
98 /** Enables/Disables common subexpression elimination.
100 * If opt_cse == 1 perform common subexpression elimination.
101 * Default: opt_cse == 1.
103 void set_opt_cse (int value);
105 /** Returns constant folding optimization setting. */
106 int get_opt_cse(void);
108 /** Enables/Disables global constant subexpression elimination.
110 * If opt_global_cse == 1 and opt_cse == 1 perform intra procedure
111 * constant subexpression elimination for floating nodes. Intra
112 * procedure cse gets the graph into state "floating". It is necessary
113 * to run pre/code motion to get the graph back into state "op_pin_state_pinned".
114 * right after a call to local_optimize with global cse turned on.
115 * Default: opt_global_cse == 0.
117 void set_opt_global_cse (int value);
119 /** Enables/Disables strength reduction.
121 * If opt_strength_red == 1 perform strength reduction.
124 * Default: opt_strength_red = 1;
126 void set_opt_strength_red (int value);
128 /** Enables/Disables output of information about strength reduction.
130 void set_opt_strength_red_verbose (int value);
132 /** Enables/Disables unreachable code elimination.
134 * If set, evaluate conditions of conditional branch and replace the
135 * branch with a Jmp/Bad Tuple.
137 * If opt_unreachable_code == 1 replace nodes (except Block,
138 * Phi and Tuple) with a Bad predecessor by the Bad node.
139 * Default: opt_unreachable_code == 1.
141 void set_opt_unreachable_code(int value);
143 /** Enables/Disables control flow optimizations.
145 * Performs Straightening, if simplifications and loop simplifications.
146 * Sets all separate control flow flags (control_flow_straightening,
147 * weak_simplification, strong_simplification and critical_edges).
149 void set_opt_control_flow(int value);
151 /** Enables/Disables Straightening. */
152 void set_opt_control_flow_straightening(int value);
154 /** Enables/Disables if simplifications in local optimizations. */
155 void set_opt_control_flow_weak_simplification(int value);
157 /** Enables/Disables strong if and loop simplification (in optimize_cf). */
158 void set_opt_control_flow_strong_simplification(int value);
160 /** Enables/Disables removal of critical control flow edges. */
161 void set_opt_critical_edges(int value);
163 /** Enables/Disables reassociation.
165 * If opt_reassociation == 1 reassociation is performed.
166 * Default: opt_reassociation == 1.
168 void set_opt_reassociation(int value);
170 /** Enables/Disables dead node elimination.
172 * If opt_dead_node_elimination == 1 deallocate all dead nodes
173 * by copying the firm graph.
174 * Default: opt_dead_node_elimination == 1. */
175 void set_opt_dead_node_elimination (int value);
177 /** Enables/Disables dead method elimination.
179 * If opt_dead_method_elimination == 1 methods never called are
181 * Default: opt_dead_method_elimination == 1. */
182 void set_opt_dead_method_elimination (int value);
183 void set_opt_dead_method_elimination_verbose (int value);
185 /** Enable/Disables inlining.
187 * If opt_inline == 1 the inlining transformation is performed.
189 void set_opt_inline (int value);
191 /** Enable/Disable optimization of dynamic method dispatch.
193 * This flag enables/disables the optimization of dynamic method dispatch.
194 * If the flag is turned on Sel nodes can be replaced by Const nodes representing
195 * the address of a function.
197 void set_opt_dyn_meth_dispatch (int value);
198 int get_opt_dyn_meth_dispatch (void);
200 /** Enable/Disable type optimization of cast nodes.
202 * Controls the optimizations in tropt.h. Default: on.
204 void set_opt_optimize_class_casts (int value);
205 void set_opt_optimize_class_casts_verbose (int value);
207 /** Restricts the behavior of cast optimization.
209 * If set, downcast are not optimized if they might be
210 * illegal as in (Super)(Sub) (new Super()). Default:
211 * 0 == not suppressed.
213 void set_opt_suppress_downcast_optimization(int value);
214 int get_opt_suppress_downcast_optimization(void);
216 /** Enable/Disable optimization of tail-recursion calls.
218 * This flag enables/disables the optimization tail-recursion call.
219 * If the flag is turned on tail-recursion calls are optimized into loops.
221 void set_opt_tail_recursion(int value);
222 void set_opt_tail_recursion_verbose(int value);
224 /** Enable/Disable floating of fragile ops.
226 * This flags enables/disables the floating of fragile operations.
227 * If this flag is on, fragile operations which are known to NOT raise
228 * an exception can be place to other basic blocks.
229 * Otherwise they remain in the block they were created.
231 void set_opt_fragile_ops(int value);
234 * Enable/Disable if conversion.
236 * If conversion tries to turn Conds into Mux nodes to eliminate
239 void set_opt_if_conversion(int value);
242 * Enable/Disable real function call optimization.
244 * Real function call optimization detects "real functions" and
245 * allows the floating of Call nodes. A "real function" is one that
246 * do only evaluate it's parameters and did not read or write memory
247 * to compute its results.
249 void set_opt_real_function_call(int value);
252 * Enable/Disable Confirm node removal during local optimization.
254 void set_opt_remove_confirm(int value);
257 * Enable/Disable scalar replacement optimization.
259 void set_opt_scalar_replacement(int value);
260 void set_opt_scalar_replacement_verbose(int value);
263 * Enable/Disable Null exception in Load and Store nodes only.
265 * If enabled, only Null pointer exception can occur at Load and
266 * store nodes. If it can be proven that the address input of these
267 * nodes is non-null, the exception edge can safely be removed.
268 * If disabled, other exceptions (like unaligned access, read-only memory,
271 * This flag is enabled by default.
273 void set_opt_ldst_only_null_ptr_exceptions(int value);
276 * Enable/Disable Selection based Null pointer check elimination.
278 * In languages, where all addresses are always Sel nodes, Null
279 * pointers can only occur as input to Sel nodes.
280 * If Null pointers are the only source for exceptions in Load and
281 * Store nodes (as typical in high level languages), we can eliminate
282 * exception edges form Load and Store as we can prove that the Sel
283 * nodes representing the Load/Store address have non-null inputs.
284 * Enabling this flag enables this elimination.
286 * Enabling this flag is meaningless if ldst_non_null_exceptions is
289 * This flags should be set for Java style languages.
291 void set_opt_sel_based_null_check_elim(int value);
293 /** Enable/Disable normalizations of the firm representation.
295 * This flag guards transformations that normalize the firm representation
296 * as removing Ids and Tuples, useless Phis, replacing SymConst(id) by
297 * Const(entity) and others.
298 * The transformations guarded by this flag are not guarded by flag
300 * Many algorithms operating on firm can not deal with constructs in
301 * the non-normalized representation.
303 * @@@ ATTENTION: not all such transformations are guarded by a flag.
305 void set_opt_normalize (int value);
307 /** Enable/Disable precise exception context.
309 * If enabled, all exceptions form a barrier for value, as in the
318 * If precise exception handling is enabled, an exception handler see a == 1,
319 * else it might see a == 2.
320 * Enable this for languages with strict exception order like Java.
322 void set_opt_precise_exc_context(int value);
325 * Save the current optimization state.
327 void save_optimization_state(optimization_state_t *state);
330 * Restore the current optimization state.
332 void restore_optimization_state(const optimization_state_t *state);
335 * Switches ALL optimizations off.
337 void all_optimizations_off(void);
340 * Possible verification modes.
342 typedef enum _firm_verification_t {
343 FIRM_VERIFICATION_OFF = 0, /**< do not verify nodes at all */
344 FIRM_VERIFICATION_ON = 1, /**< do node verification and assert on error in debug version */
345 FIRM_VERIFICATION_REPORT = 2, /**< do node verification, but report to stderr only */
346 FIRM_VERIFICATION_ERROR_ONLY = 3 /**< do node verification, but NEVER do assert nor report */
347 } firm_verification_t;
349 /** Select verification of nodes.
351 * Per default the verification is in mode NODE_VERIFICATION_ASSERT.
352 * Turn the verification off during development to check partial implementations.
354 void do_node_verification(firm_verification_t mode);
356 #endif /* _IRFLAG_H_ */