1 /* Interprocedural constant propagation
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
3 Contributed by Razya Ladelsky <RAZYA@il.ibm.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* Interprocedural constant propagation. The aim of interprocedural constant
22 propagation (IPCP) is to find which function's argument has the same
23 constant value in each invocation throughout the whole program. For example,
24 consider the following program:
28 printf ("value is %d",y);
48 The IPCP algorithm will find that g's formal argument y is always called
51 The algorithm used is based on "Interprocedural Constant Propagation", by
52 Challahan David, Keith D Cooper, Ken Kennedy, Linda Torczon, Comp86, pg
55 The optimization is divided into three stages:
57 First stage - intraprocedural analysis
58 =======================================
59 This phase computes jump_function and modification flags.
61 A jump function for a callsite represents the values passed as an actual
62 arguments of a given callsite. There are three types of values:
63 Pass through - the caller's formal parameter is passed as an actual argument.
64 Constant - a constant is passed as an actual argument.
65 Unknown - neither of the above.
67 The jump function info, ipa_jump_func, is stored in ipa_edge_args
68 structure (defined in ipa_prop.h and pointed to by cgraph_node->aux)
69 modified_flags are defined in ipa_node_params structure
70 (defined in ipa_prop.h and pointed to by cgraph_edge->aux).
72 -ipcp_init_stage() is the first stage driver.
74 Second stage - interprocedural analysis
75 ========================================
76 This phase does the interprocedural constant propagation.
77 It computes lattices for all formal parameters in the program
78 and their value that may be:
80 BOTTOM - non constant.
81 CONSTANT - constant value.
83 Lattice describing a formal parameter p will have a constant value if all
84 callsites invoking this function have the same constant value passed to p.
86 The lattices are stored in ipcp_lattice which is itself in ipa_node_params
87 structure (defined in ipa_prop.h and pointed to by cgraph_edge->aux).
89 -ipcp_iterate_stage() is the second stage driver.
91 Third phase - transformation of function code
92 ============================================
93 Propagates the constant-valued formals into the function.
94 For each function whose parameters are constants, we create its clone.
96 Then we process the clone in two ways:
97 1. We insert an assignment statement 'parameter = const' at the beginning
98 of the cloned function.
99 2. For read-only parameters that do not live in memory, we replace all their
100 uses with the constant.
102 We also need to modify some callsites to call the cloned functions instead
103 of the original ones. For a callsite passing an argument found to be a
104 constant by IPCP, there are two different cases to handle:
105 1. A constant is passed as an argument. In this case the callsite in the
106 should be redirected to call the cloned callee.
107 2. A parameter (of the caller) passed as an argument (pass through
108 argument). In such cases both the caller and the callee have clones and
109 only the callsite in the cloned caller is redirected to call to the
112 This update is done in two steps: First all cloned functions are created
113 during a traversal of the call graph, during which all callsites are
114 redirected to call the cloned function. Then the callsites are traversed
115 and many calls redirected back to fit the description above.
117 -ipcp_insert_stage() is the third phase driver.
123 #include "coretypes.h"
127 #include "ipa-prop.h"
128 #include "tree-flow.h"
129 #include "tree-pass.h"
132 #include "diagnostic.h"
133 #include "tree-dump.h"
134 #include "tree-inline.h"
138 /* Number of functions identified as candidates for cloning. When not cloning
139 we can simplify iterate stage not forcing it to go through the decision
140 on what is profitable and what not. */
141 static int n_cloning_candidates;
143 /* Maximal count found in program. */
144 static gcov_type max_count;
146 /* Cgraph nodes that has been completely replaced by cloning during iterate
147 * stage and will be removed after ipcp is finished. */
148 static bitmap dead_nodes;
150 static void ipcp_print_profile_data (FILE *);
151 static void ipcp_function_scale_print (FILE *);
153 /* Get the original node field of ipa_node_params associated with node NODE. */
154 static inline struct cgraph_node *
155 ipcp_get_orig_node (struct cgraph_node *node)
157 return IPA_NODE_REF (node)->ipcp_orig_node;
160 /* Return true if NODE describes a cloned/versioned function. */
162 ipcp_node_is_clone (struct cgraph_node *node)
164 return (ipcp_get_orig_node (node) != NULL);
167 /* Create ipa_node_params and its data structures for NEW_NODE. Set ORIG_NODE
168 as the ipcp_orig_node field in ipa_node_params. */
170 ipcp_init_cloned_node (struct cgraph_node *orig_node,
171 struct cgraph_node *new_node)
173 ipa_check_create_node_params ();
174 ipa_initialize_node_params (new_node);
175 IPA_NODE_REF (new_node)->ipcp_orig_node = orig_node;
178 /* Perform intraprocedrual analysis needed for ipcp. */
180 ipcp_analyze_node (struct cgraph_node *node)
182 /* Unreachable nodes should have been eliminated before ipcp. */
183 gcc_assert (node->needed || node->reachable);
185 ipa_initialize_node_params (node);
186 ipa_detect_param_modifications (node);
189 /* Return scale for NODE. */
190 static inline gcov_type
191 ipcp_get_node_scale (struct cgraph_node *node)
193 return IPA_NODE_REF (node)->count_scale;
196 /* Set COUNT as scale for NODE. */
198 ipcp_set_node_scale (struct cgraph_node *node, gcov_type count)
200 IPA_NODE_REF (node)->count_scale = count;
203 /* Return whether LAT is a constant lattice. */
205 ipcp_lat_is_const (struct ipcp_lattice *lat)
207 if (lat->type == IPA_CONST_VALUE)
213 /* Return whether LAT is a constant lattice that ipa-cp can actually insert
214 into the code (i.e. constants excluding member pointers and pointers). */
216 ipcp_lat_is_insertable (struct ipcp_lattice *lat)
218 return lat->type == IPA_CONST_VALUE;
221 /* Return true if LAT1 and LAT2 are equal. */
223 ipcp_lats_are_equal (struct ipcp_lattice *lat1, struct ipcp_lattice *lat2)
225 gcc_assert (ipcp_lat_is_const (lat1) && ipcp_lat_is_const (lat2));
226 if (lat1->type != lat2->type)
229 if (operand_equal_p (lat1->constant, lat2->constant, 0))
235 /* Compute Meet arithmetics:
236 Meet (IPA_BOTTOM, x) = IPA_BOTTOM
238 Meet (const_a,const_b) = IPA_BOTTOM, if const_a != const_b.
239 MEET (const_a,const_b) = const_a, if const_a == const_b.*/
241 ipa_lattice_meet (struct ipcp_lattice *res, struct ipcp_lattice *lat1,
242 struct ipcp_lattice *lat2)
244 if (lat1->type == IPA_BOTTOM || lat2->type == IPA_BOTTOM)
246 res->type = IPA_BOTTOM;
249 if (lat1->type == IPA_TOP)
251 res->type = lat2->type;
252 res->constant = lat2->constant;
255 if (lat2->type == IPA_TOP)
257 res->type = lat1->type;
258 res->constant = lat1->constant;
261 if (!ipcp_lats_are_equal (lat1, lat2))
263 res->type = IPA_BOTTOM;
266 res->type = lat1->type;
267 res->constant = lat1->constant;
270 /* Return the lattice corresponding to the Ith formal parameter of the function
271 described by INFO. */
272 static inline struct ipcp_lattice *
273 ipcp_get_lattice (struct ipa_node_params *info, int i)
275 return &(info->params[i].ipcp_lattice);
278 /* Given the jump function JFUNC, compute the lattice LAT that describes the
279 value coming down the callsite. INFO describes the caller node so that
280 pass-through jump functions can be evaluated. */
282 ipcp_lattice_from_jfunc (struct ipa_node_params *info, struct ipcp_lattice *lat,
283 struct ipa_jump_func *jfunc)
285 if (jfunc->type == IPA_JF_CONST)
287 lat->type = IPA_CONST_VALUE;
288 lat->constant = jfunc->value.constant;
290 else if (jfunc->type == IPA_JF_PASS_THROUGH)
292 struct ipcp_lattice *caller_lat;
295 caller_lat = ipcp_get_lattice (info, jfunc->value.pass_through.formal_id);
296 lat->type = caller_lat->type;
297 if (caller_lat->type != IPA_CONST_VALUE)
299 cst = caller_lat->constant;
301 if (jfunc->value.pass_through.operation != NOP_EXPR)
304 if (TREE_CODE_CLASS (jfunc->value.pass_through.operation)
306 restype = boolean_type_node;
308 restype = TREE_TYPE (cst);
309 cst = fold_binary (jfunc->value.pass_through.operation,
310 restype, cst, jfunc->value.pass_through.operand);
312 if (!cst || !is_gimple_ip_invariant (cst))
313 lat->type = IPA_BOTTOM;
316 else if (jfunc->type == IPA_JF_ANCESTOR)
318 struct ipcp_lattice *caller_lat;
322 caller_lat = ipcp_get_lattice (info, jfunc->value.ancestor.formal_id);
323 lat->type = caller_lat->type;
324 if (caller_lat->type != IPA_CONST_VALUE)
326 if (TREE_CODE (caller_lat->constant) != ADDR_EXPR)
328 /* This can happen when the constant is a NULL pointer. */
329 lat->type = IPA_BOTTOM;
332 t = TREE_OPERAND (caller_lat->constant, 0);
333 ok = build_ref_for_offset (&t, TREE_TYPE (t),
334 jfunc->value.ancestor.offset,
335 jfunc->value.ancestor.type, false);
338 lat->type = IPA_BOTTOM;
339 lat->constant = NULL_TREE;
342 lat->constant = build_fold_addr_expr (t);
345 lat->type = IPA_BOTTOM;
348 /* True when OLD_LAT and NEW_LAT values are not the same. */
351 ipcp_lattice_changed (struct ipcp_lattice *old_lat,
352 struct ipcp_lattice *new_lat)
354 if (old_lat->type == new_lat->type)
356 if (!ipcp_lat_is_const (old_lat))
358 if (ipcp_lats_are_equal (old_lat, new_lat))
364 /* Print all ipcp_lattices of all functions to F. */
366 ipcp_print_all_lattices (FILE * f)
368 struct cgraph_node *node;
371 fprintf (f, "\nLattice:\n");
372 for (node = cgraph_nodes; node; node = node->next)
374 struct ipa_node_params *info;
378 info = IPA_NODE_REF (node);
379 fprintf (f, " Node: %s:\n", cgraph_node_name (node));
380 count = ipa_get_param_count (info);
381 for (i = 0; i < count; i++)
383 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
385 fprintf (f, " param [%d]: ", i);
386 if (lat->type == IPA_CONST_VALUE)
388 fprintf (f, "type is CONST ");
389 print_generic_expr (f, lat->constant, 0);
392 else if (lat->type == IPA_TOP)
393 fprintf (f, "type is TOP\n");
395 fprintf (f, "type is BOTTOM\n");
400 /* Return true if ipcp algorithms would allow cloning NODE. */
403 ipcp_versionable_function_p (struct cgraph_node *node)
405 tree decl = node->decl;
408 /* There are a number of generic reasons functions cannot be versioned. */
409 if (!tree_versionable_function_p (decl))
412 /* Removing arguments doesn't work if the function takes varargs. */
413 if (DECL_STRUCT_FUNCTION (decl)->stdarg)
416 /* Removing arguments doesn't work if we use __builtin_apply_args. */
417 FOR_EACH_BB_FN (bb, DECL_STRUCT_FUNCTION (decl))
419 gimple_stmt_iterator gsi;
420 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
422 const_gimple stmt = gsi_stmt (gsi);
425 if (!is_gimple_call (stmt))
427 t = gimple_call_fndecl (stmt);
430 if (DECL_BUILT_IN_CLASS (t) == BUILT_IN_NORMAL
431 && DECL_FUNCTION_CODE (t) == BUILT_IN_APPLY_ARGS)
439 /* Return true if this NODE is viable candidate for cloning. */
441 ipcp_cloning_candidate_p (struct cgraph_node *node)
445 gcov_type direct_call_sum = 0;
446 struct cgraph_edge *e;
448 /* We never clone functions that are not visible from outside.
449 FIXME: in future we should clone such functions when they are called with
450 different constants, but current ipcp implementation is not good on this.
452 if (cgraph_only_called_directly_p (node) || !node->analyzed)
455 if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
458 fprintf (dump_file, "Not considering %s for cloning; body is overwrittable.\n",
459 cgraph_node_name (node));
462 if (!ipcp_versionable_function_p (node))
465 fprintf (dump_file, "Not considering %s for cloning; body is not versionable.\n",
466 cgraph_node_name (node));
469 for (e = node->callers; e; e = e->next_caller)
471 direct_call_sum += e->count;
473 if (cgraph_maybe_hot_edge_p (e))
480 fprintf (dump_file, "Not considering %s for cloning; no direct calls.\n",
481 cgraph_node_name (node));
484 if (node->local.inline_summary.self_size < n_calls)
487 fprintf (dump_file, "Considering %s for cloning; code would shrink.\n",
488 cgraph_node_name (node));
492 if (!flag_ipa_cp_clone)
495 fprintf (dump_file, "Not considering %s for cloning; -fipa-cp-clone disabled.\n",
496 cgraph_node_name (node));
500 if (!optimize_function_for_speed_p (DECL_STRUCT_FUNCTION (node->decl)))
503 fprintf (dump_file, "Not considering %s for cloning; optimizing it for size.\n",
504 cgraph_node_name (node));
508 /* When profile is available and function is hot, propagate into it even if
509 calls seems cold; constant propagation can improve function's speed
513 if (direct_call_sum > node->count * 90 / 100)
516 fprintf (dump_file, "Considering %s for cloning; usually called directly.\n",
517 cgraph_node_name (node));
524 fprintf (dump_file, "Not considering %s for cloning; no hot calls.\n",
525 cgraph_node_name (node));
529 fprintf (dump_file, "Considering %s for cloning.\n",
530 cgraph_node_name (node));
534 /* Initialize ipcp_lattices array. The lattices corresponding to supported
535 types (integers, real types and Fortran constants defined as const_decls)
536 are initialized to IPA_TOP, the rest of them to IPA_BOTTOM. */
538 ipcp_initialize_node_lattices (struct cgraph_node *node)
541 struct ipa_node_params *info = IPA_NODE_REF (node);
542 enum ipa_lattice_type type;
544 if (ipa_is_called_with_var_arguments (info))
546 else if (cgraph_only_called_directly_p (node))
548 /* When cloning is allowed, we can assume that externally visible functions
549 are not called. We will compensate this by cloning later. */
550 else if (ipcp_cloning_candidate_p (node))
551 type = IPA_TOP, n_cloning_candidates ++;
555 for (i = 0; i < ipa_get_param_count (info) ; i++)
556 ipcp_get_lattice (info, i)->type = type;
559 /* build INTEGER_CST tree with type TREE_TYPE and value according to LAT.
562 build_const_val (struct ipcp_lattice *lat, tree tree_type)
566 gcc_assert (ipcp_lat_is_const (lat));
569 if (!useless_type_conversion_p (tree_type, TREE_TYPE (val)))
571 if (fold_convertible_p (tree_type, val))
572 return fold_build1 (NOP_EXPR, tree_type, val);
574 return fold_build1 (VIEW_CONVERT_EXPR, tree_type, val);
579 /* Compute the proper scale for NODE. It is the ratio between the number of
580 direct calls (represented on the incoming cgraph_edges) and sum of all
581 invocations of NODE (represented as count in cgraph_node).
583 FIXME: This code is wrong. Since the callers can be also clones and
584 the clones are not scaled yet, the sums gets unrealistically high.
585 To properly compute the counts, we would need to do propagation across
586 callgraph (as external call to A might imply call to non-clonned B
587 if A's clone calls clonned B). */
589 ipcp_compute_node_scale (struct cgraph_node *node)
592 struct cgraph_edge *cs;
595 /* Compute sum of all counts of callers. */
596 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
598 /* Work around the unrealistically high sum problem. We just don't want
599 the non-cloned body to have negative or very low frequency. Since
600 majority of execution time will be spent in clones anyway, this should
601 give good enough profile. */
602 if (sum > node->count * 9 / 10)
603 sum = node->count * 9 / 10;
604 if (node->count == 0)
605 ipcp_set_node_scale (node, 0);
607 ipcp_set_node_scale (node, sum * REG_BR_PROB_BASE / node->count);
610 /* Initialization and computation of IPCP data structures. This is the initial
611 intraprocedural analysis of functions, which gathers information to be
612 propagated later on. */
614 ipcp_init_stage (void)
616 struct cgraph_node *node;
617 struct cgraph_edge *cs;
619 for (node = cgraph_nodes; node; node = node->next)
621 ipcp_analyze_node (node);
622 for (node = cgraph_nodes; node; node = node->next)
626 /* building jump functions */
627 for (cs = node->callees; cs; cs = cs->next_callee)
629 /* We do not need to bother analyzing calls to unknown
630 functions unless they may become known during lto/whopr. */
631 if (!cs->callee->analyzed && !flag_lto && !flag_whopr)
633 ipa_count_arguments (cs);
634 if (ipa_get_cs_argument_count (IPA_EDGE_REF (cs))
635 != ipa_get_param_count (IPA_NODE_REF (cs->callee)))
637 /* Handle cases of functions with
638 a variable number of parameters. */
639 ipa_set_called_with_variable_arg (IPA_NODE_REF (cs->callee));
640 if (flag_indirect_inlining)
641 ipa_compute_jump_functions (cs);
644 ipa_compute_jump_functions (cs);
649 /* Return true if there are some formal parameters whose value is IPA_TOP (in
650 the whole compilation unit). Change their values to IPA_BOTTOM, since they
651 most probably get their values from outside of this compilation unit. */
653 ipcp_change_tops_to_bottom (void)
656 struct cgraph_node *node;
660 for (node = cgraph_nodes; node; node = node->next)
662 struct ipa_node_params *info = IPA_NODE_REF (node);
663 count = ipa_get_param_count (info);
664 for (i = 0; i < count; i++)
666 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
667 if (lat->type == IPA_TOP)
672 fprintf (dump_file, "Forcing param ");
673 print_generic_expr (dump_file, ipa_get_param (info, i), 0);
674 fprintf (dump_file, " of node %s to bottom.\n",
675 cgraph_node_name (node));
677 lat->type = IPA_BOTTOM;
684 /* Interprocedural analysis. The algorithm propagates constants from the
685 caller's parameters to the callee's arguments. */
687 ipcp_propagate_stage (void)
690 struct ipcp_lattice inc_lat = { IPA_BOTTOM, NULL };
691 struct ipcp_lattice new_lat = { IPA_BOTTOM, NULL };
692 struct ipcp_lattice *dest_lat;
693 struct cgraph_edge *cs;
694 struct ipa_jump_func *jump_func;
695 struct ipa_func_list *wl;
698 ipa_check_create_node_params ();
699 ipa_check_create_edge_args ();
701 /* Initialize worklist to contain all functions. */
702 wl = ipa_init_func_list ();
705 struct cgraph_node *node = ipa_pop_func_from_list (&wl);
706 struct ipa_node_params *info = IPA_NODE_REF (node);
708 for (cs = node->callees; cs; cs = cs->next_callee)
710 struct ipa_node_params *callee_info = IPA_NODE_REF (cs->callee);
711 struct ipa_edge_args *args = IPA_EDGE_REF (cs);
713 if (ipa_is_called_with_var_arguments (callee_info)
714 || !cs->callee->analyzed
715 || ipa_is_called_with_var_arguments (callee_info))
718 count = ipa_get_cs_argument_count (args);
719 for (i = 0; i < count; i++)
721 jump_func = ipa_get_ith_jump_func (args, i);
722 ipcp_lattice_from_jfunc (info, &inc_lat, jump_func);
723 dest_lat = ipcp_get_lattice (callee_info, i);
724 ipa_lattice_meet (&new_lat, &inc_lat, dest_lat);
725 if (ipcp_lattice_changed (&new_lat, dest_lat))
727 dest_lat->type = new_lat.type;
728 dest_lat->constant = new_lat.constant;
729 ipa_push_func_to_list (&wl, cs->callee);
736 /* Call the constant propagation algorithm and re-call it if necessary
737 (if there are undetermined values left). */
739 ipcp_iterate_stage (void)
741 struct cgraph_node *node;
742 n_cloning_candidates = 0;
745 fprintf (dump_file, "\nIPA iterate stage:\n\n");
748 ipa_update_after_lto_read ();
750 for (node = cgraph_nodes; node; node = node->next)
752 ipcp_initialize_node_lattices (node);
753 ipcp_compute_node_scale (node);
755 if (dump_file && (dump_flags & TDF_DETAILS))
757 ipcp_print_all_lattices (dump_file);
758 ipcp_function_scale_print (dump_file);
761 ipcp_propagate_stage ();
762 if (ipcp_change_tops_to_bottom ())
763 /* Some lattices have changed from IPA_TOP to IPA_BOTTOM.
764 This change should be propagated. */
766 gcc_assert (n_cloning_candidates);
767 ipcp_propagate_stage ();
771 fprintf (dump_file, "\nIPA lattices after propagation:\n");
772 ipcp_print_all_lattices (dump_file);
773 if (dump_flags & TDF_DETAILS)
774 ipcp_print_profile_data (dump_file);
778 /* Check conditions to forbid constant insertion to function described by
781 ipcp_node_modifiable_p (struct cgraph_node *node)
783 /* Once we will be able to do in-place replacement, we can be more
785 return ipcp_versionable_function_p (node);
788 /* Print count scale data structures. */
790 ipcp_function_scale_print (FILE * f)
792 struct cgraph_node *node;
794 for (node = cgraph_nodes; node; node = node->next)
798 fprintf (f, "printing scale for %s: ", cgraph_node_name (node));
799 fprintf (f, "value is " HOST_WIDE_INT_PRINT_DEC
800 " \n", (HOST_WIDE_INT) ipcp_get_node_scale (node));
804 /* Print counts of all cgraph nodes. */
806 ipcp_print_func_profile_counts (FILE * f)
808 struct cgraph_node *node;
810 for (node = cgraph_nodes; node; node = node->next)
812 fprintf (f, "function %s: ", cgraph_node_name (node));
813 fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC
814 " \n", (HOST_WIDE_INT) node->count);
818 /* Print counts of all cgraph edges. */
820 ipcp_print_call_profile_counts (FILE * f)
822 struct cgraph_node *node;
823 struct cgraph_edge *cs;
825 for (node = cgraph_nodes; node; node = node->next)
827 for (cs = node->callees; cs; cs = cs->next_callee)
829 fprintf (f, "%s -> %s ", cgraph_node_name (cs->caller),
830 cgraph_node_name (cs->callee));
831 fprintf (f, "count is " HOST_WIDE_INT_PRINT_DEC " \n",
832 (HOST_WIDE_INT) cs->count);
837 /* Print profile info for all functions. */
839 ipcp_print_profile_data (FILE * f)
841 fprintf (f, "\nNODE COUNTS :\n");
842 ipcp_print_func_profile_counts (f);
843 fprintf (f, "\nCS COUNTS stage:\n");
844 ipcp_print_call_profile_counts (f);
847 /* Build and initialize ipa_replace_map struct according to LAT. This struct is
848 processed by versioning, which operates according to the flags set.
849 PARM_TREE is the formal parameter found to be constant. LAT represents the
851 static struct ipa_replace_map *
852 ipcp_create_replace_map (tree parm_tree, struct ipcp_lattice *lat)
854 struct ipa_replace_map *replace_map;
857 replace_map = GGC_NEW (struct ipa_replace_map);
858 const_val = build_const_val (lat, TREE_TYPE (parm_tree));
861 fprintf (dump_file, " replacing param ");
862 print_generic_expr (dump_file, parm_tree, 0);
863 fprintf (dump_file, " with const ");
864 print_generic_expr (dump_file, const_val, 0);
865 fprintf (dump_file, "\n");
867 replace_map->old_tree = parm_tree;
868 replace_map->new_tree = const_val;
869 replace_map->replace_p = true;
870 replace_map->ref_p = false;
875 /* Return true if this callsite should be redirected to the original callee
876 (instead of the cloned one). */
878 ipcp_need_redirect_p (struct cgraph_edge *cs)
880 struct ipa_node_params *orig_callee_info;
882 struct ipa_jump_func *jump_func;
883 struct cgraph_node *node = cs->callee, *orig;
885 if (!n_cloning_candidates)
888 if ((orig = ipcp_get_orig_node (node)) != NULL)
890 if (ipcp_get_orig_node (cs->caller))
893 orig_callee_info = IPA_NODE_REF (node);
894 count = ipa_get_param_count (orig_callee_info);
895 for (i = 0; i < count; i++)
897 struct ipcp_lattice *lat = ipcp_get_lattice (orig_callee_info, i);
898 if (ipcp_lat_is_const (lat))
900 jump_func = ipa_get_ith_jump_func (IPA_EDGE_REF (cs), i);
901 if (jump_func->type != IPA_JF_CONST)
909 /* Fix the callsites and the call graph after function cloning was done. */
911 ipcp_update_callgraph (void)
913 struct cgraph_node *node;
915 for (node = cgraph_nodes; node; node = node->next)
916 if (node->analyzed && ipcp_node_is_clone (node))
918 bitmap args_to_skip = BITMAP_ALLOC (NULL);
919 struct cgraph_node *orig_node = ipcp_get_orig_node (node);
920 struct ipa_node_params *info = IPA_NODE_REF (orig_node);
921 int i, count = ipa_get_param_count (info);
922 struct cgraph_edge *cs, *next;
924 for (i = 0; i < count; i++)
926 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
927 tree parm_tree = ipa_get_param (info, i);
929 /* We can proactively remove obviously unused arguments. */
930 if (is_gimple_reg (parm_tree)
931 && !gimple_default_def (DECL_STRUCT_FUNCTION (orig_node->decl),
934 bitmap_set_bit (args_to_skip, i);
938 if (lat->type == IPA_CONST_VALUE)
939 bitmap_set_bit (args_to_skip, i);
941 for (cs = node->callers; cs; cs = next)
943 next = cs->next_caller;
944 if (!ipcp_node_is_clone (cs->caller) && ipcp_need_redirect_p (cs))
945 cgraph_redirect_edge_callee (cs, orig_node);
950 /* Update profiling info for versioned functions and the functions they were
953 ipcp_update_profiling (void)
955 struct cgraph_node *node, *orig_node;
956 gcov_type scale, scale_complement;
957 struct cgraph_edge *cs;
959 for (node = cgraph_nodes; node; node = node->next)
961 if (ipcp_node_is_clone (node))
963 orig_node = ipcp_get_orig_node (node);
964 scale = ipcp_get_node_scale (orig_node);
965 node->count = orig_node->count * scale / REG_BR_PROB_BASE;
966 scale_complement = REG_BR_PROB_BASE - scale;
968 orig_node->count * scale_complement / REG_BR_PROB_BASE;
969 for (cs = node->callees; cs; cs = cs->next_callee)
970 cs->count = cs->count * scale / REG_BR_PROB_BASE;
971 for (cs = orig_node->callees; cs; cs = cs->next_callee)
972 cs->count = cs->count * scale_complement / REG_BR_PROB_BASE;
977 /* If NODE was cloned, how much would program grow? */
979 ipcp_estimate_growth (struct cgraph_node *node)
981 struct cgraph_edge *cs;
982 int redirectable_node_callers = 0;
983 int removable_args = 0;
984 bool need_original = !cgraph_only_called_directly_p (node);
985 struct ipa_node_params *info;
989 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
990 if (cs->caller == node || !ipcp_need_redirect_p (cs))
991 redirectable_node_callers++;
993 need_original = true;
995 /* If we will be able to fully replace orignal node, we never increase
1000 info = IPA_NODE_REF (node);
1001 count = ipa_get_param_count (info);
1002 for (i = 0; i < count; i++)
1004 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
1005 tree parm_tree = ipa_get_param (info, i);
1007 /* We can proactively remove obviously unused arguments. */
1008 if (is_gimple_reg (parm_tree)
1009 && !gimple_default_def (DECL_STRUCT_FUNCTION (node->decl),
1013 if (lat->type == IPA_CONST_VALUE)
1017 /* We make just very simple estimate of savings for removal of operand from
1018 call site. Precise cost is dificult to get, as our size metric counts
1019 constants and moves as free. Generally we are looking for cases that
1020 small function is called very many times. */
1021 growth = node->local.inline_summary.self_size
1022 - removable_args * redirectable_node_callers;
1029 /* Estimate cost of cloning NODE. */
1031 ipcp_estimate_cloning_cost (struct cgraph_node *node)
1034 gcov_type count_sum = 1;
1035 struct cgraph_edge *e;
1038 cost = ipcp_estimate_growth (node) * 1000;
1042 fprintf (dump_file, "Versioning of %s will save code size\n",
1043 cgraph_node_name (node));
1047 for (e = node->callers; e; e = e->next_caller)
1048 if (!bitmap_bit_p (dead_nodes, e->caller->uid)
1049 && !ipcp_need_redirect_p (e))
1051 count_sum += e->count;
1052 freq_sum += e->frequency + 1;
1056 cost /= count_sum * 1000 / max_count + 1;
1058 cost /= freq_sum * 1000 / REG_BR_PROB_BASE + 1;
1060 fprintf (dump_file, "Cost of versioning %s is %i, (size: %i, freq: %i)\n",
1061 cgraph_node_name (node), cost, node->local.inline_summary.self_size,
1066 /* Return number of live constant parameters. */
1068 ipcp_const_param_count (struct cgraph_node *node)
1070 int const_param = 0;
1071 struct ipa_node_params *info = IPA_NODE_REF (node);
1072 int count = ipa_get_param_count (info);
1075 for (i = 0; i < count; i++)
1077 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
1078 tree parm_tree = ipa_get_param (info, i);
1079 if (ipcp_lat_is_insertable (lat)
1080 /* Do not count obviously unused arguments. */
1081 && (!is_gimple_reg (parm_tree)
1082 || gimple_default_def (DECL_STRUCT_FUNCTION (node->decl),
1089 /* Propagate the constant parameters found by ipcp_iterate_stage()
1090 to the function's code. */
1092 ipcp_insert_stage (void)
1094 struct cgraph_node *node, *node1 = NULL;
1096 VEC (cgraph_edge_p, heap) * redirect_callers;
1097 VEC (ipa_replace_map_p,gc)* replace_trees;
1098 int node_callers, count;
1100 struct ipa_replace_map *replace_param;
1102 long overall_size = 0, new_size = 0;
1105 ipa_check_create_node_params ();
1106 ipa_check_create_edge_args ();
1108 fprintf (dump_file, "\nIPA insert stage:\n\n");
1110 dead_nodes = BITMAP_ALLOC (NULL);
1112 for (node = cgraph_nodes; node; node = node->next)
1115 if (node->count > max_count)
1116 max_count = node->count;
1117 overall_size += node->local.inline_summary.self_size;
1120 max_new_size = overall_size;
1121 if (max_new_size < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS))
1122 max_new_size = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS);
1123 max_new_size = max_new_size * PARAM_VALUE (PARAM_IPCP_UNIT_GROWTH) / 100 + 1;
1125 /* First collect all functions we proved to have constant arguments to heap. */
1126 heap = fibheap_new ();
1127 for (node = cgraph_nodes; node; node = node->next)
1129 struct ipa_node_params *info;
1130 /* Propagation of the constant is forbidden in certain conditions. */
1131 if (!node->analyzed || !ipcp_node_modifiable_p (node))
1133 info = IPA_NODE_REF (node);
1134 if (ipa_is_called_with_var_arguments (info))
1136 if (ipcp_const_param_count (node))
1137 node->aux = fibheap_insert (heap, ipcp_estimate_cloning_cost (node), node);
1140 /* Now clone in priority order until code size growth limits are met or
1142 while (!fibheap_empty (heap))
1144 struct ipa_node_params *info;
1146 bitmap args_to_skip;
1147 struct cgraph_edge *cs;
1149 node = (struct cgraph_node *)fibheap_extract_min (heap);
1152 fprintf (dump_file, "considering function %s\n",
1153 cgraph_node_name (node));
1155 growth = ipcp_estimate_growth (node);
1157 if (new_size + growth > max_new_size)
1160 && optimize_function_for_size_p (DECL_STRUCT_FUNCTION (node->decl)))
1163 fprintf (dump_file, "Not versioning, cold code would grow");
1169 /* Look if original function becomes dead after clonning. */
1170 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
1171 if (cs->caller == node || ipcp_need_redirect_p (cs))
1173 if (!cs && cgraph_only_called_directly_p (node))
1174 bitmap_set_bit (dead_nodes, node->uid);
1176 info = IPA_NODE_REF (node);
1177 count = ipa_get_param_count (info);
1179 replace_trees = VEC_alloc (ipa_replace_map_p, gc, 1);
1180 args_to_skip = BITMAP_GGC_ALLOC ();
1181 for (i = 0; i < count; i++)
1183 struct ipcp_lattice *lat = ipcp_get_lattice (info, i);
1184 parm_tree = ipa_get_param (info, i);
1186 /* We can proactively remove obviously unused arguments. */
1187 if (is_gimple_reg (parm_tree)
1188 && !gimple_default_def (DECL_STRUCT_FUNCTION (node->decl),
1191 bitmap_set_bit (args_to_skip, i);
1195 if (lat->type == IPA_CONST_VALUE)
1198 ipcp_create_replace_map (parm_tree, lat);
1199 VEC_safe_push (ipa_replace_map_p, gc, replace_trees, replace_param);
1200 bitmap_set_bit (args_to_skip, i);
1204 /* Compute how many callers node has. */
1206 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
1208 redirect_callers = VEC_alloc (cgraph_edge_p, heap, node_callers);
1209 for (cs = node->callers; cs != NULL; cs = cs->next_caller)
1210 VEC_quick_push (cgraph_edge_p, redirect_callers, cs);
1212 /* Redirecting all the callers of the node to the
1213 new versioned node. */
1215 cgraph_create_virtual_clone (node, redirect_callers, replace_trees,
1217 args_to_skip = NULL;
1218 VEC_free (cgraph_edge_p, heap, redirect_callers);
1219 replace_trees = NULL;
1224 fprintf (dump_file, "versioned function %s with growth %i, overall %i\n",
1225 cgraph_node_name (node), (int)growth, (int)new_size);
1226 ipcp_init_cloned_node (node, node1);
1228 /* TODO: We can use indirect inlning info to produce new calls. */
1231 dump_function_to_file (node1->decl, dump_file, dump_flags);
1233 for (cs = node->callees; cs; cs = cs->next_callee)
1234 if (cs->callee->aux)
1236 fibheap_delete_node (heap, (fibnode_t) cs->callee->aux);
1237 cs->callee->aux = fibheap_insert (heap,
1238 ipcp_estimate_cloning_cost (cs->callee),
1243 while (!fibheap_empty (heap))
1246 fprintf (dump_file, "skipping function %s\n",
1247 cgraph_node_name (node));
1248 node = (struct cgraph_node *) fibheap_extract_min (heap);
1251 fibheap_delete (heap);
1252 BITMAP_FREE (dead_nodes);
1253 ipcp_update_callgraph ();
1254 ipcp_update_profiling ();
1257 /* The IPCP driver. */
1261 cgraph_remove_unreachable_nodes (true,dump_file);
1264 fprintf (dump_file, "\nIPA structures before propagation:\n");
1265 if (dump_flags & TDF_DETAILS)
1266 ipa_print_all_params (dump_file);
1267 ipa_print_all_jump_functions (dump_file);
1269 /* 2. Do the interprocedural propagation. */
1270 ipcp_iterate_stage ();
1271 /* 3. Insert the constants found to the functions. */
1272 ipcp_insert_stage ();
1273 if (dump_file && (dump_flags & TDF_DETAILS))
1275 fprintf (dump_file, "\nProfiling info after insert stage:\n");
1276 ipcp_print_profile_data (dump_file);
1278 /* Free all IPCP structures. */
1279 free_all_ipa_structures_after_ipa_cp ();
1281 fprintf (dump_file, "\nIPA constant propagation end\n");
1285 /* Note function body size. */
1287 ipcp_generate_summary (void)
1290 fprintf (dump_file, "\nIPA constant propagation start:\n");
1291 ipa_check_create_node_params ();
1292 ipa_check_create_edge_args ();
1293 ipa_register_cgraph_hooks ();
1294 /* 1. Call the init stage to initialize
1295 the ipa_node_params and ipa_edge_args structures. */
1299 /* Write ipcp summary for nodes in SET. */
1301 ipcp_write_summary (cgraph_node_set set)
1303 ipa_prop_write_jump_functions (set);
1306 /* Read ipcp summary. */
1308 ipcp_read_summary (void)
1310 ipa_prop_read_jump_functions ();
1313 /* Gate for IPCP optimization. */
1315 cgraph_gate_cp (void)
1320 struct ipa_opt_pass_d pass_ipa_cp =
1325 cgraph_gate_cp, /* gate */
1326 ipcp_driver, /* execute */
1329 0, /* static_pass_number */
1330 TV_IPA_CONSTANT_PROP, /* tv_id */
1331 0, /* properties_required */
1332 0, /* properties_provided */
1333 0, /* properties_destroyed */
1334 0, /* todo_flags_start */
1335 TODO_dump_cgraph | TODO_dump_func |
1336 TODO_remove_functions /* todo_flags_finish */
1338 ipcp_generate_summary, /* generate_summary */
1339 ipcp_write_summary, /* write_summary */
1340 ipcp_read_summary, /* read_summary */
1341 NULL, /* function_read_summary */
1342 lto_ipa_fixup_call_notes, /* stmt_fixup */
1344 NULL, /* function_transform */
1345 NULL, /* variable_transform */