1 /* Data references and dependences detectors.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
3 Contributed by Sebastian Pop <pop@cri.ensmp.fr>
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 /* This pass walks a given loop structure searching for array
22 references. The information about the array accesses is recorded
23 in DATA_REFERENCE structures.
25 The basic test for determining the dependences is:
26 given two access functions chrec1 and chrec2 to a same array, and
27 x and y two vectors from the iteration domain, the same element of
28 the array is accessed twice at iterations x and y if and only if:
29 | chrec1 (x) == chrec2 (y).
31 The goals of this analysis are:
33 - to determine the independence: the relation between two
34 independent accesses is qualified with the chrec_known (this
35 information allows a loop parallelization),
37 - when two data references access the same data, to qualify the
38 dependence relation with classic dependence representations:
42 - loop carried level dependence
43 - polyhedron dependence
44 or with the chains of recurrences based representation,
46 - to define a knowledge base for storing the data dependence
49 - to define an interface to access this data.
54 - subscript: given two array accesses a subscript is the tuple
55 composed of the access functions for a given dimension. Example:
56 Given A[f1][f2][f3] and B[g1][g2][g3], there are three subscripts:
57 (f1, g1), (f2, g2), (f3, g3).
59 - Diophantine equation: an equation whose coefficients and
60 solutions are integer constants, for example the equation
62 has an integer solution x = 1 and y = -1.
66 - "Advanced Compilation for High Performance Computing" by Randy
67 Allen and Ken Kennedy.
68 http://citeseer.ist.psu.edu/goff91practical.html
70 - "Loop Transformations for Restructuring Compilers - The Foundations"
78 #include "coretypes.h"
83 /* These RTL headers are needed for basic-block.h. */
85 #include "basic-block.h"
86 #include "diagnostic.h"
87 #include "tree-flow.h"
88 #include "tree-dump.h"
91 #include "tree-data-ref.h"
92 #include "tree-scalar-evolution.h"
93 #include "tree-pass.h"
94 #include "langhooks.h"
96 static struct datadep_stats
98 int num_dependence_tests;
99 int num_dependence_dependent;
100 int num_dependence_independent;
101 int num_dependence_undetermined;
103 int num_subscript_tests;
104 int num_subscript_undetermined;
105 int num_same_subscript_function;
108 int num_ziv_independent;
109 int num_ziv_dependent;
110 int num_ziv_unimplemented;
113 int num_siv_independent;
114 int num_siv_dependent;
115 int num_siv_unimplemented;
118 int num_miv_independent;
119 int num_miv_dependent;
120 int num_miv_unimplemented;
123 static bool subscript_dependence_tester_1 (struct data_dependence_relation *,
124 struct data_reference *,
125 struct data_reference *,
127 /* Returns true iff A divides B. */
130 tree_fold_divides_p (const_tree a, const_tree b)
132 gcc_assert (TREE_CODE (a) == INTEGER_CST);
133 gcc_assert (TREE_CODE (b) == INTEGER_CST);
134 return integer_zerop (int_const_binop (TRUNC_MOD_EXPR, b, a, 0));
137 /* Returns true iff A divides B. */
140 int_divides_p (int a, int b)
142 return ((b % a) == 0);
147 /* Dump into FILE all the data references from DATAREFS. */
150 dump_data_references (FILE *file, VEC (data_reference_p, heap) *datarefs)
153 struct data_reference *dr;
155 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
156 dump_data_reference (file, dr);
159 /* Dump to STDERR all the dependence relations from DDRS. */
162 debug_data_dependence_relations (VEC (ddr_p, heap) *ddrs)
164 dump_data_dependence_relations (stderr, ddrs);
167 /* Dump into FILE all the dependence relations from DDRS. */
170 dump_data_dependence_relations (FILE *file,
171 VEC (ddr_p, heap) *ddrs)
174 struct data_dependence_relation *ddr;
176 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
177 dump_data_dependence_relation (file, ddr);
180 /* Dump function for a DATA_REFERENCE structure. */
183 dump_data_reference (FILE *outf,
184 struct data_reference *dr)
188 fprintf (outf, "(Data Ref: \n stmt: ");
189 print_gimple_stmt (outf, DR_STMT (dr), 0, 0);
190 fprintf (outf, " ref: ");
191 print_generic_stmt (outf, DR_REF (dr), 0);
192 fprintf (outf, " base_object: ");
193 print_generic_stmt (outf, DR_BASE_OBJECT (dr), 0);
195 for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++)
197 fprintf (outf, " Access function %d: ", i);
198 print_generic_stmt (outf, DR_ACCESS_FN (dr, i), 0);
200 fprintf (outf, ")\n");
203 /* Dumps the affine function described by FN to the file OUTF. */
206 dump_affine_function (FILE *outf, affine_fn fn)
211 print_generic_expr (outf, VEC_index (tree, fn, 0), TDF_SLIM);
212 for (i = 1; VEC_iterate (tree, fn, i, coef); i++)
214 fprintf (outf, " + ");
215 print_generic_expr (outf, coef, TDF_SLIM);
216 fprintf (outf, " * x_%u", i);
220 /* Dumps the conflict function CF to the file OUTF. */
223 dump_conflict_function (FILE *outf, conflict_function *cf)
227 if (cf->n == NO_DEPENDENCE)
228 fprintf (outf, "no dependence\n");
229 else if (cf->n == NOT_KNOWN)
230 fprintf (outf, "not known\n");
233 for (i = 0; i < cf->n; i++)
236 dump_affine_function (outf, cf->fns[i]);
237 fprintf (outf, "]\n");
242 /* Dump function for a SUBSCRIPT structure. */
245 dump_subscript (FILE *outf, struct subscript *subscript)
247 conflict_function *cf = SUB_CONFLICTS_IN_A (subscript);
249 fprintf (outf, "\n (subscript \n");
250 fprintf (outf, " iterations_that_access_an_element_twice_in_A: ");
251 dump_conflict_function (outf, cf);
252 if (CF_NONTRIVIAL_P (cf))
254 tree last_iteration = SUB_LAST_CONFLICT (subscript);
255 fprintf (outf, " last_conflict: ");
256 print_generic_stmt (outf, last_iteration, 0);
259 cf = SUB_CONFLICTS_IN_B (subscript);
260 fprintf (outf, " iterations_that_access_an_element_twice_in_B: ");
261 dump_conflict_function (outf, cf);
262 if (CF_NONTRIVIAL_P (cf))
264 tree last_iteration = SUB_LAST_CONFLICT (subscript);
265 fprintf (outf, " last_conflict: ");
266 print_generic_stmt (outf, last_iteration, 0);
269 fprintf (outf, " (Subscript distance: ");
270 print_generic_stmt (outf, SUB_DISTANCE (subscript), 0);
271 fprintf (outf, " )\n");
272 fprintf (outf, " )\n");
275 /* Print the classic direction vector DIRV to OUTF. */
278 print_direction_vector (FILE *outf,
284 for (eq = 0; eq < length; eq++)
286 enum data_dependence_direction dir = dirv[eq];
291 fprintf (outf, " +");
294 fprintf (outf, " -");
297 fprintf (outf, " =");
299 case dir_positive_or_equal:
300 fprintf (outf, " +=");
302 case dir_positive_or_negative:
303 fprintf (outf, " +-");
305 case dir_negative_or_equal:
306 fprintf (outf, " -=");
309 fprintf (outf, " *");
312 fprintf (outf, "indep");
316 fprintf (outf, "\n");
319 /* Print a vector of direction vectors. */
322 print_dir_vectors (FILE *outf, VEC (lambda_vector, heap) *dir_vects,
328 for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, v); j++)
329 print_direction_vector (outf, v, length);
332 /* Print a vector of distance vectors. */
335 print_dist_vectors (FILE *outf, VEC (lambda_vector, heap) *dist_vects,
341 for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, v); j++)
342 print_lambda_vector (outf, v, length);
348 debug_data_dependence_relation (struct data_dependence_relation *ddr)
350 dump_data_dependence_relation (stderr, ddr);
353 /* Dump function for a DATA_DEPENDENCE_RELATION structure. */
356 dump_data_dependence_relation (FILE *outf,
357 struct data_dependence_relation *ddr)
359 struct data_reference *dra, *drb;
361 fprintf (outf, "(Data Dep: \n");
363 if (!ddr || DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
365 fprintf (outf, " (don't know)\n)\n");
371 dump_data_reference (outf, dra);
372 dump_data_reference (outf, drb);
374 if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
375 fprintf (outf, " (no dependence)\n");
377 else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
382 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
384 fprintf (outf, " access_fn_A: ");
385 print_generic_stmt (outf, DR_ACCESS_FN (dra, i), 0);
386 fprintf (outf, " access_fn_B: ");
387 print_generic_stmt (outf, DR_ACCESS_FN (drb, i), 0);
388 dump_subscript (outf, DDR_SUBSCRIPT (ddr, i));
391 fprintf (outf, " inner loop index: %d\n", DDR_INNER_LOOP (ddr));
392 fprintf (outf, " loop nest: (");
393 for (i = 0; VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
394 fprintf (outf, "%d ", loopi->num);
395 fprintf (outf, ")\n");
397 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
399 fprintf (outf, " distance_vector: ");
400 print_lambda_vector (outf, DDR_DIST_VECT (ddr, i),
404 for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++)
406 fprintf (outf, " direction_vector: ");
407 print_direction_vector (outf, DDR_DIR_VECT (ddr, i),
412 fprintf (outf, ")\n");
415 /* Dump function for a DATA_DEPENDENCE_DIRECTION structure. */
418 dump_data_dependence_direction (FILE *file,
419 enum data_dependence_direction dir)
435 case dir_positive_or_negative:
436 fprintf (file, "+-");
439 case dir_positive_or_equal:
440 fprintf (file, "+=");
443 case dir_negative_or_equal:
444 fprintf (file, "-=");
456 /* Dumps the distance and direction vectors in FILE. DDRS contains
457 the dependence relations, and VECT_SIZE is the size of the
458 dependence vectors, or in other words the number of loops in the
462 dump_dist_dir_vectors (FILE *file, VEC (ddr_p, heap) *ddrs)
465 struct data_dependence_relation *ddr;
468 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
469 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE && DDR_AFFINE_P (ddr))
471 for (j = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), j, v); j++)
473 fprintf (file, "DISTANCE_V (");
474 print_lambda_vector (file, v, DDR_NB_LOOPS (ddr));
475 fprintf (file, ")\n");
478 for (j = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), j, v); j++)
480 fprintf (file, "DIRECTION_V (");
481 print_direction_vector (file, v, DDR_NB_LOOPS (ddr));
482 fprintf (file, ")\n");
486 fprintf (file, "\n\n");
489 /* Dumps the data dependence relations DDRS in FILE. */
492 dump_ddrs (FILE *file, VEC (ddr_p, heap) *ddrs)
495 struct data_dependence_relation *ddr;
497 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
498 dump_data_dependence_relation (file, ddr);
500 fprintf (file, "\n\n");
503 /* Helper function for split_constant_offset. Expresses OP0 CODE OP1
504 (the type of the result is TYPE) as VAR + OFF, where OFF is a nonzero
505 constant of type ssizetype, and returns true. If we cannot do this
506 with OFF nonzero, OFF and VAR are set to NULL_TREE instead and false
510 split_constant_offset_1 (tree type, tree op0, enum tree_code code, tree op1,
511 tree *var, tree *off)
515 enum tree_code ocode = code;
523 *var = build_int_cst (type, 0);
524 *off = fold_convert (ssizetype, op0);
527 case POINTER_PLUS_EXPR:
532 split_constant_offset (op0, &var0, &off0);
533 split_constant_offset (op1, &var1, &off1);
534 *var = fold_build2 (code, type, var0, var1);
535 *off = size_binop (ocode, off0, off1);
539 if (TREE_CODE (op1) != INTEGER_CST)
542 split_constant_offset (op0, &var0, &off0);
543 *var = fold_build2 (MULT_EXPR, type, var0, op1);
544 *off = size_binop (MULT_EXPR, off0, fold_convert (ssizetype, op1));
550 HOST_WIDE_INT pbitsize, pbitpos;
551 enum machine_mode pmode;
552 int punsignedp, pvolatilep;
554 if (!handled_component_p (op0))
557 base = get_inner_reference (op0, &pbitsize, &pbitpos, &poffset,
558 &pmode, &punsignedp, &pvolatilep, false);
560 if (pbitpos % BITS_PER_UNIT != 0)
562 base = build_fold_addr_expr (base);
563 off0 = ssize_int (pbitpos / BITS_PER_UNIT);
567 split_constant_offset (poffset, &poffset, &off1);
568 off0 = size_binop (PLUS_EXPR, off0, off1);
569 if (POINTER_TYPE_P (TREE_TYPE (base)))
570 base = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (base),
571 base, fold_convert (sizetype, poffset));
573 base = fold_build2 (PLUS_EXPR, TREE_TYPE (base), base,
574 fold_convert (TREE_TYPE (base), poffset));
577 var0 = fold_convert (type, base);
579 /* If variable length types are involved, punt, otherwise casts
580 might be converted into ARRAY_REFs in gimplify_conversion.
581 To compute that ARRAY_REF's element size TYPE_SIZE_UNIT, which
582 possibly no longer appears in current GIMPLE, might resurface.
583 This perhaps could run
584 if (CONVERT_EXPR_P (var0))
586 gimplify_conversion (&var0);
587 // Attempt to fill in any within var0 found ARRAY_REF's
588 // element size from corresponding op embedded ARRAY_REF,
589 // if unsuccessful, just punt.
591 while (POINTER_TYPE_P (type))
592 type = TREE_TYPE (type);
593 if (int_size_in_bytes (type) < 0)
603 gimple def_stmt = SSA_NAME_DEF_STMT (op0);
604 enum tree_code subcode;
606 if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
609 var0 = gimple_assign_rhs1 (def_stmt);
610 subcode = gimple_assign_rhs_code (def_stmt);
611 var1 = gimple_assign_rhs2 (def_stmt);
613 return split_constant_offset_1 (type, var0, subcode, var1, var, off);
621 /* Expresses EXP as VAR + OFF, where off is a constant. The type of OFF
622 will be ssizetype. */
625 split_constant_offset (tree exp, tree *var, tree *off)
627 tree type = TREE_TYPE (exp), otype, op0, op1, e, o;
631 *off = ssize_int (0);
634 if (automatically_generated_chrec_p (exp))
637 otype = TREE_TYPE (exp);
638 code = TREE_CODE (exp);
639 extract_ops_from_tree (exp, &code, &op0, &op1);
640 if (split_constant_offset_1 (otype, op0, code, op1, &e, &o))
642 *var = fold_convert (type, e);
647 /* Returns the address ADDR of an object in a canonical shape (without nop
648 casts, and with type of pointer to the object). */
651 canonicalize_base_object_address (tree addr)
657 /* The base address may be obtained by casting from integer, in that case
659 if (!POINTER_TYPE_P (TREE_TYPE (addr)))
662 if (TREE_CODE (addr) != ADDR_EXPR)
665 return build_fold_addr_expr (TREE_OPERAND (addr, 0));
668 /* Analyzes the behavior of the memory reference DR in the innermost loop that
672 dr_analyze_innermost (struct data_reference *dr)
674 gimple stmt = DR_STMT (dr);
675 struct loop *loop = loop_containing_stmt (stmt);
676 tree ref = DR_REF (dr);
677 HOST_WIDE_INT pbitsize, pbitpos;
679 enum machine_mode pmode;
680 int punsignedp, pvolatilep;
681 affine_iv base_iv, offset_iv;
682 tree init, dinit, step;
684 if (dump_file && (dump_flags & TDF_DETAILS))
685 fprintf (dump_file, "analyze_innermost: ");
687 base = get_inner_reference (ref, &pbitsize, &pbitpos, &poffset,
688 &pmode, &punsignedp, &pvolatilep, false);
689 gcc_assert (base != NULL_TREE);
691 if (pbitpos % BITS_PER_UNIT != 0)
693 if (dump_file && (dump_flags & TDF_DETAILS))
694 fprintf (dump_file, "failed: bit offset alignment.\n");
698 base = build_fold_addr_expr (base);
699 if (!simple_iv (loop, stmt, base, &base_iv, false))
701 if (dump_file && (dump_flags & TDF_DETAILS))
702 fprintf (dump_file, "failed: evolution of base is not affine.\n");
707 offset_iv.base = ssize_int (0);
708 offset_iv.step = ssize_int (0);
710 else if (!simple_iv (loop, stmt, poffset, &offset_iv, false))
712 if (dump_file && (dump_flags & TDF_DETAILS))
713 fprintf (dump_file, "failed: evolution of offset is not affine.\n");
717 init = ssize_int (pbitpos / BITS_PER_UNIT);
718 split_constant_offset (base_iv.base, &base_iv.base, &dinit);
719 init = size_binop (PLUS_EXPR, init, dinit);
720 split_constant_offset (offset_iv.base, &offset_iv.base, &dinit);
721 init = size_binop (PLUS_EXPR, init, dinit);
723 step = size_binop (PLUS_EXPR,
724 fold_convert (ssizetype, base_iv.step),
725 fold_convert (ssizetype, offset_iv.step));
727 DR_BASE_ADDRESS (dr) = canonicalize_base_object_address (base_iv.base);
729 DR_OFFSET (dr) = fold_convert (ssizetype, offset_iv.base);
733 DR_ALIGNED_TO (dr) = size_int (highest_pow2_factor (offset_iv.base));
735 if (dump_file && (dump_flags & TDF_DETAILS))
736 fprintf (dump_file, "success.\n");
739 /* Determines the base object and the list of indices of memory reference
740 DR, analyzed in loop nest NEST. */
743 dr_analyze_indices (struct data_reference *dr, struct loop *nest)
745 gimple stmt = DR_STMT (dr);
746 struct loop *loop = loop_containing_stmt (stmt);
747 VEC (tree, heap) *access_fns = NULL;
748 tree ref = unshare_expr (DR_REF (dr)), aref = ref, op;
749 tree base, off, access_fn;
750 basic_block before_loop = block_before_loop (nest);
752 while (handled_component_p (aref))
754 if (TREE_CODE (aref) == ARRAY_REF)
756 op = TREE_OPERAND (aref, 1);
757 access_fn = analyze_scalar_evolution (loop, op);
758 access_fn = instantiate_scev (before_loop, loop, access_fn);
759 VEC_safe_push (tree, heap, access_fns, access_fn);
761 TREE_OPERAND (aref, 1) = build_int_cst (TREE_TYPE (op), 0);
764 aref = TREE_OPERAND (aref, 0);
767 if (INDIRECT_REF_P (aref))
769 op = TREE_OPERAND (aref, 0);
770 access_fn = analyze_scalar_evolution (loop, op);
771 access_fn = instantiate_scev (before_loop, loop, access_fn);
772 base = initial_condition (access_fn);
773 split_constant_offset (base, &base, &off);
774 access_fn = chrec_replace_initial_condition (access_fn,
775 fold_convert (TREE_TYPE (base), off));
777 TREE_OPERAND (aref, 0) = base;
778 VEC_safe_push (tree, heap, access_fns, access_fn);
781 DR_BASE_OBJECT (dr) = ref;
782 DR_ACCESS_FNS (dr) = access_fns;
785 /* Extracts the alias analysis information from the memory reference DR. */
788 dr_analyze_alias (struct data_reference *dr)
790 gimple stmt = DR_STMT (dr);
791 tree ref = DR_REF (dr);
792 tree base = get_base_address (ref), addr, smt = NULL_TREE;
799 else if (INDIRECT_REF_P (base))
801 addr = TREE_OPERAND (base, 0);
802 if (TREE_CODE (addr) == SSA_NAME)
804 smt = symbol_mem_tag (SSA_NAME_VAR (addr));
805 DR_PTR_INFO (dr) = SSA_NAME_PTR_INFO (addr);
809 DR_SYMBOL_TAG (dr) = smt;
811 vops = BITMAP_ALLOC (NULL);
812 FOR_EACH_SSA_TREE_OPERAND (op, stmt, it, SSA_OP_VIRTUAL_USES)
814 bitmap_set_bit (vops, DECL_UID (SSA_NAME_VAR (op)));
820 /* Returns true if the address of DR is invariant. */
823 dr_address_invariant_p (struct data_reference *dr)
828 for (i = 0; VEC_iterate (tree, DR_ACCESS_FNS (dr), i, idx); i++)
829 if (tree_contains_chrecs (idx, NULL))
835 /* Frees data reference DR. */
838 free_data_ref (data_reference_p dr)
840 BITMAP_FREE (DR_VOPS (dr));
841 VEC_free (tree, heap, DR_ACCESS_FNS (dr));
845 /* Analyzes memory reference MEMREF accessed in STMT. The reference
846 is read if IS_READ is true, write otherwise. Returns the
847 data_reference description of MEMREF. NEST is the outermost loop of the
848 loop nest in that the reference should be analyzed. */
850 struct data_reference *
851 create_data_ref (struct loop *nest, tree memref, gimple stmt, bool is_read)
853 struct data_reference *dr;
855 if (dump_file && (dump_flags & TDF_DETAILS))
857 fprintf (dump_file, "Creating dr for ");
858 print_generic_expr (dump_file, memref, TDF_SLIM);
859 fprintf (dump_file, "\n");
862 dr = XCNEW (struct data_reference);
864 DR_REF (dr) = memref;
865 DR_IS_READ (dr) = is_read;
867 dr_analyze_innermost (dr);
868 dr_analyze_indices (dr, nest);
869 dr_analyze_alias (dr);
871 if (dump_file && (dump_flags & TDF_DETAILS))
873 fprintf (dump_file, "\tbase_address: ");
874 print_generic_expr (dump_file, DR_BASE_ADDRESS (dr), TDF_SLIM);
875 fprintf (dump_file, "\n\toffset from base address: ");
876 print_generic_expr (dump_file, DR_OFFSET (dr), TDF_SLIM);
877 fprintf (dump_file, "\n\tconstant offset from base address: ");
878 print_generic_expr (dump_file, DR_INIT (dr), TDF_SLIM);
879 fprintf (dump_file, "\n\tstep: ");
880 print_generic_expr (dump_file, DR_STEP (dr), TDF_SLIM);
881 fprintf (dump_file, "\n\taligned to: ");
882 print_generic_expr (dump_file, DR_ALIGNED_TO (dr), TDF_SLIM);
883 fprintf (dump_file, "\n\tbase_object: ");
884 print_generic_expr (dump_file, DR_BASE_OBJECT (dr), TDF_SLIM);
885 fprintf (dump_file, "\n\tsymbol tag: ");
886 print_generic_expr (dump_file, DR_SYMBOL_TAG (dr), TDF_SLIM);
887 fprintf (dump_file, "\n");
893 /* Returns true if FNA == FNB. */
896 affine_function_equal_p (affine_fn fna, affine_fn fnb)
898 unsigned i, n = VEC_length (tree, fna);
900 if (n != VEC_length (tree, fnb))
903 for (i = 0; i < n; i++)
904 if (!operand_equal_p (VEC_index (tree, fna, i),
905 VEC_index (tree, fnb, i), 0))
911 /* If all the functions in CF are the same, returns one of them,
912 otherwise returns NULL. */
915 common_affine_function (conflict_function *cf)
920 if (!CF_NONTRIVIAL_P (cf))
925 for (i = 1; i < cf->n; i++)
926 if (!affine_function_equal_p (comm, cf->fns[i]))
932 /* Returns the base of the affine function FN. */
935 affine_function_base (affine_fn fn)
937 return VEC_index (tree, fn, 0);
940 /* Returns true if FN is a constant. */
943 affine_function_constant_p (affine_fn fn)
948 for (i = 1; VEC_iterate (tree, fn, i, coef); i++)
949 if (!integer_zerop (coef))
955 /* Returns true if FN is the zero constant function. */
958 affine_function_zero_p (affine_fn fn)
960 return (integer_zerop (affine_function_base (fn))
961 && affine_function_constant_p (fn));
964 /* Returns a signed integer type with the largest precision from TA
968 signed_type_for_types (tree ta, tree tb)
970 if (TYPE_PRECISION (ta) > TYPE_PRECISION (tb))
971 return signed_type_for (ta);
973 return signed_type_for (tb);
976 /* Applies operation OP on affine functions FNA and FNB, and returns the
980 affine_fn_op (enum tree_code op, affine_fn fna, affine_fn fnb)
986 if (VEC_length (tree, fnb) > VEC_length (tree, fna))
988 n = VEC_length (tree, fna);
989 m = VEC_length (tree, fnb);
993 n = VEC_length (tree, fnb);
994 m = VEC_length (tree, fna);
997 ret = VEC_alloc (tree, heap, m);
998 for (i = 0; i < n; i++)
1000 tree type = signed_type_for_types (TREE_TYPE (VEC_index (tree, fna, i)),
1001 TREE_TYPE (VEC_index (tree, fnb, i)));
1003 VEC_quick_push (tree, ret,
1004 fold_build2 (op, type,
1005 VEC_index (tree, fna, i),
1006 VEC_index (tree, fnb, i)));
1009 for (; VEC_iterate (tree, fna, i, coef); i++)
1010 VEC_quick_push (tree, ret,
1011 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1012 coef, integer_zero_node));
1013 for (; VEC_iterate (tree, fnb, i, coef); i++)
1014 VEC_quick_push (tree, ret,
1015 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1016 integer_zero_node, coef));
1021 /* Returns the sum of affine functions FNA and FNB. */
1024 affine_fn_plus (affine_fn fna, affine_fn fnb)
1026 return affine_fn_op (PLUS_EXPR, fna, fnb);
1029 /* Returns the difference of affine functions FNA and FNB. */
1032 affine_fn_minus (affine_fn fna, affine_fn fnb)
1034 return affine_fn_op (MINUS_EXPR, fna, fnb);
1037 /* Frees affine function FN. */
1040 affine_fn_free (affine_fn fn)
1042 VEC_free (tree, heap, fn);
1045 /* Determine for each subscript in the data dependence relation DDR
1049 compute_subscript_distance (struct data_dependence_relation *ddr)
1051 conflict_function *cf_a, *cf_b;
1052 affine_fn fn_a, fn_b, diff;
1054 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
1058 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
1060 struct subscript *subscript;
1062 subscript = DDR_SUBSCRIPT (ddr, i);
1063 cf_a = SUB_CONFLICTS_IN_A (subscript);
1064 cf_b = SUB_CONFLICTS_IN_B (subscript);
1066 fn_a = common_affine_function (cf_a);
1067 fn_b = common_affine_function (cf_b);
1070 SUB_DISTANCE (subscript) = chrec_dont_know;
1073 diff = affine_fn_minus (fn_a, fn_b);
1075 if (affine_function_constant_p (diff))
1076 SUB_DISTANCE (subscript) = affine_function_base (diff);
1078 SUB_DISTANCE (subscript) = chrec_dont_know;
1080 affine_fn_free (diff);
1085 /* Returns the conflict function for "unknown". */
1087 static conflict_function *
1088 conflict_fn_not_known (void)
1090 conflict_function *fn = XCNEW (conflict_function);
1096 /* Returns the conflict function for "independent". */
1098 static conflict_function *
1099 conflict_fn_no_dependence (void)
1101 conflict_function *fn = XCNEW (conflict_function);
1102 fn->n = NO_DEPENDENCE;
1107 /* Returns true if the address of OBJ is invariant in LOOP. */
1110 object_address_invariant_in_loop_p (const struct loop *loop, const_tree obj)
1112 while (handled_component_p (obj))
1114 if (TREE_CODE (obj) == ARRAY_REF)
1116 /* Index of the ARRAY_REF was zeroed in analyze_indices, thus we only
1117 need to check the stride and the lower bound of the reference. */
1118 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1120 || chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 3),
1124 else if (TREE_CODE (obj) == COMPONENT_REF)
1126 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1130 obj = TREE_OPERAND (obj, 0);
1133 if (!INDIRECT_REF_P (obj))
1136 return !chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 0),
1140 /* Returns true if A and B are accesses to different objects, or to different
1141 fields of the same object. */
1144 disjoint_objects_p (tree a, tree b)
1146 tree base_a, base_b;
1147 VEC (tree, heap) *comp_a = NULL, *comp_b = NULL;
1150 base_a = get_base_address (a);
1151 base_b = get_base_address (b);
1155 && base_a != base_b)
1158 if (!operand_equal_p (base_a, base_b, 0))
1161 /* Compare the component references of A and B. We must start from the inner
1162 ones, so record them to the vector first. */
1163 while (handled_component_p (a))
1165 VEC_safe_push (tree, heap, comp_a, a);
1166 a = TREE_OPERAND (a, 0);
1168 while (handled_component_p (b))
1170 VEC_safe_push (tree, heap, comp_b, b);
1171 b = TREE_OPERAND (b, 0);
1177 if (VEC_length (tree, comp_a) == 0
1178 || VEC_length (tree, comp_b) == 0)
1181 a = VEC_pop (tree, comp_a);
1182 b = VEC_pop (tree, comp_b);
1184 /* Real and imaginary part of a variable do not alias. */
1185 if ((TREE_CODE (a) == REALPART_EXPR
1186 && TREE_CODE (b) == IMAGPART_EXPR)
1187 || (TREE_CODE (a) == IMAGPART_EXPR
1188 && TREE_CODE (b) == REALPART_EXPR))
1194 if (TREE_CODE (a) != TREE_CODE (b))
1197 /* Nothing to do for ARRAY_REFs, as the indices of array_refs in
1198 DR_BASE_OBJECT are always zero. */
1199 if (TREE_CODE (a) == ARRAY_REF)
1201 else if (TREE_CODE (a) == COMPONENT_REF)
1203 if (operand_equal_p (TREE_OPERAND (a, 1), TREE_OPERAND (b, 1), 0))
1206 /* Different fields of unions may overlap. */
1207 base_a = TREE_OPERAND (a, 0);
1208 if (TREE_CODE (TREE_TYPE (base_a)) == UNION_TYPE)
1211 /* Different fields of structures cannot. */
1219 VEC_free (tree, heap, comp_a);
1220 VEC_free (tree, heap, comp_b);
1225 /* Returns false if we can prove that data references A and B do not alias,
1229 dr_may_alias_p (const struct data_reference *a, const struct data_reference *b)
1231 const_tree addr_a = DR_BASE_ADDRESS (a);
1232 const_tree addr_b = DR_BASE_ADDRESS (b);
1233 const_tree type_a, type_b;
1234 const_tree decl_a = NULL_TREE, decl_b = NULL_TREE;
1236 /* If the sets of virtual operands are disjoint, the memory references do not
1238 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
1241 /* If the accessed objects are disjoint, the memory references do not
1243 if (disjoint_objects_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b)))
1246 if (!addr_a || !addr_b)
1249 /* If the references are based on different static objects, they cannot alias
1250 (PTA should be able to disambiguate such accesses, but often it fails to,
1251 since currently we cannot distinguish between pointer and offset in pointer
1253 if (TREE_CODE (addr_a) == ADDR_EXPR
1254 && TREE_CODE (addr_b) == ADDR_EXPR)
1255 return TREE_OPERAND (addr_a, 0) == TREE_OPERAND (addr_b, 0);
1257 /* An instruction writing through a restricted pointer is "independent" of any
1258 instruction reading or writing through a different restricted pointer,
1259 in the same block/scope. */
1261 type_a = TREE_TYPE (addr_a);
1262 type_b = TREE_TYPE (addr_b);
1263 gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b));
1265 if (TREE_CODE (addr_a) == SSA_NAME)
1266 decl_a = SSA_NAME_VAR (addr_a);
1267 if (TREE_CODE (addr_b) == SSA_NAME)
1268 decl_b = SSA_NAME_VAR (addr_b);
1270 if (TYPE_RESTRICT (type_a) && TYPE_RESTRICT (type_b)
1271 && (!DR_IS_READ (a) || !DR_IS_READ (b))
1272 && decl_a && DECL_P (decl_a)
1273 && decl_b && DECL_P (decl_b)
1275 && TREE_CODE (DECL_CONTEXT (decl_a)) == FUNCTION_DECL
1276 && DECL_CONTEXT (decl_a) == DECL_CONTEXT (decl_b))
1282 static void compute_self_dependence (struct data_dependence_relation *);
1284 /* Initialize a data dependence relation between data accesses A and
1285 B. NB_LOOPS is the number of loops surrounding the references: the
1286 size of the classic distance/direction vectors. */
1288 static struct data_dependence_relation *
1289 initialize_data_dependence_relation (struct data_reference *a,
1290 struct data_reference *b,
1291 VEC (loop_p, heap) *loop_nest)
1293 struct data_dependence_relation *res;
1296 res = XNEW (struct data_dependence_relation);
1299 DDR_LOOP_NEST (res) = NULL;
1300 DDR_REVERSED_P (res) = false;
1301 DDR_SUBSCRIPTS (res) = NULL;
1302 DDR_DIR_VECTS (res) = NULL;
1303 DDR_DIST_VECTS (res) = NULL;
1305 if (a == NULL || b == NULL)
1307 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1311 /* If the data references do not alias, then they are independent. */
1312 if (!dr_may_alias_p (a, b))
1314 DDR_ARE_DEPENDENT (res) = chrec_known;
1318 /* When the references are exactly the same, don't spend time doing
1319 the data dependence tests, just initialize the ddr and return. */
1320 if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
1322 DDR_AFFINE_P (res) = true;
1323 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1324 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1325 DDR_LOOP_NEST (res) = loop_nest;
1326 DDR_INNER_LOOP (res) = 0;
1327 DDR_SELF_REFERENCE (res) = true;
1328 compute_self_dependence (res);
1332 /* If the references do not access the same object, we do not know
1333 whether they alias or not. */
1334 if (!operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0))
1336 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1340 /* If the base of the object is not invariant in the loop nest, we cannot
1341 analyze it. TODO -- in fact, it would suffice to record that there may
1342 be arbitrary dependences in the loops where the base object varies. */
1343 if (!object_address_invariant_in_loop_p (VEC_index (loop_p, loop_nest, 0),
1344 DR_BASE_OBJECT (a)))
1346 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1350 gcc_assert (DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b));
1352 DDR_AFFINE_P (res) = true;
1353 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1354 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1355 DDR_LOOP_NEST (res) = loop_nest;
1356 DDR_INNER_LOOP (res) = 0;
1357 DDR_SELF_REFERENCE (res) = false;
1359 for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
1361 struct subscript *subscript;
1363 subscript = XNEW (struct subscript);
1364 SUB_CONFLICTS_IN_A (subscript) = conflict_fn_not_known ();
1365 SUB_CONFLICTS_IN_B (subscript) = conflict_fn_not_known ();
1366 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
1367 SUB_DISTANCE (subscript) = chrec_dont_know;
1368 VEC_safe_push (subscript_p, heap, DDR_SUBSCRIPTS (res), subscript);
1374 /* Frees memory used by the conflict function F. */
1377 free_conflict_function (conflict_function *f)
1381 if (CF_NONTRIVIAL_P (f))
1383 for (i = 0; i < f->n; i++)
1384 affine_fn_free (f->fns[i]);
1389 /* Frees memory used by SUBSCRIPTS. */
1392 free_subscripts (VEC (subscript_p, heap) *subscripts)
1397 for (i = 0; VEC_iterate (subscript_p, subscripts, i, s); i++)
1399 free_conflict_function (s->conflicting_iterations_in_a);
1400 free_conflict_function (s->conflicting_iterations_in_b);
1403 VEC_free (subscript_p, heap, subscripts);
1406 /* Set DDR_ARE_DEPENDENT to CHREC and finalize the subscript overlap
1410 finalize_ddr_dependent (struct data_dependence_relation *ddr,
1413 if (dump_file && (dump_flags & TDF_DETAILS))
1415 fprintf (dump_file, "(dependence classified: ");
1416 print_generic_expr (dump_file, chrec, 0);
1417 fprintf (dump_file, ")\n");
1420 DDR_ARE_DEPENDENT (ddr) = chrec;
1421 free_subscripts (DDR_SUBSCRIPTS (ddr));
1422 DDR_SUBSCRIPTS (ddr) = NULL;
1425 /* The dependence relation DDR cannot be represented by a distance
1429 non_affine_dependence_relation (struct data_dependence_relation *ddr)
1431 if (dump_file && (dump_flags & TDF_DETAILS))
1432 fprintf (dump_file, "(Dependence relation cannot be represented by distance vector.) \n");
1434 DDR_AFFINE_P (ddr) = false;
1439 /* This section contains the classic Banerjee tests. */
1441 /* Returns true iff CHREC_A and CHREC_B are not dependent on any index
1442 variables, i.e., if the ZIV (Zero Index Variable) test is true. */
1445 ziv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1447 return (evolution_function_is_constant_p (chrec_a)
1448 && evolution_function_is_constant_p (chrec_b));
1451 /* Returns true iff CHREC_A and CHREC_B are dependent on an index
1452 variable, i.e., if the SIV (Single Index Variable) test is true. */
1455 siv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1457 if ((evolution_function_is_constant_p (chrec_a)
1458 && evolution_function_is_univariate_p (chrec_b))
1459 || (evolution_function_is_constant_p (chrec_b)
1460 && evolution_function_is_univariate_p (chrec_a)))
1463 if (evolution_function_is_univariate_p (chrec_a)
1464 && evolution_function_is_univariate_p (chrec_b))
1466 switch (TREE_CODE (chrec_a))
1468 case POLYNOMIAL_CHREC:
1469 switch (TREE_CODE (chrec_b))
1471 case POLYNOMIAL_CHREC:
1472 if (CHREC_VARIABLE (chrec_a) != CHREC_VARIABLE (chrec_b))
1487 /* Creates a conflict function with N dimensions. The affine functions
1488 in each dimension follow. */
1490 static conflict_function *
1491 conflict_fn (unsigned n, ...)
1494 conflict_function *ret = XCNEW (conflict_function);
1497 gcc_assert (0 < n && n <= MAX_DIM);
1501 for (i = 0; i < n; i++)
1502 ret->fns[i] = va_arg (ap, affine_fn);
1508 /* Returns constant affine function with value CST. */
1511 affine_fn_cst (tree cst)
1513 affine_fn fn = VEC_alloc (tree, heap, 1);
1514 VEC_quick_push (tree, fn, cst);
1518 /* Returns affine function with single variable, CST + COEF * x_DIM. */
1521 affine_fn_univar (tree cst, unsigned dim, tree coef)
1523 affine_fn fn = VEC_alloc (tree, heap, dim + 1);
1526 gcc_assert (dim > 0);
1527 VEC_quick_push (tree, fn, cst);
1528 for (i = 1; i < dim; i++)
1529 VEC_quick_push (tree, fn, integer_zero_node);
1530 VEC_quick_push (tree, fn, coef);
1534 /* Analyze a ZIV (Zero Index Variable) subscript. *OVERLAPS_A and
1535 *OVERLAPS_B are initialized to the functions that describe the
1536 relation between the elements accessed twice by CHREC_A and
1537 CHREC_B. For k >= 0, the following property is verified:
1539 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1542 analyze_ziv_subscript (tree chrec_a,
1544 conflict_function **overlaps_a,
1545 conflict_function **overlaps_b,
1546 tree *last_conflicts)
1548 tree type, difference;
1549 dependence_stats.num_ziv++;
1551 if (dump_file && (dump_flags & TDF_DETAILS))
1552 fprintf (dump_file, "(analyze_ziv_subscript \n");
1554 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1555 chrec_a = chrec_convert (type, chrec_a, NULL);
1556 chrec_b = chrec_convert (type, chrec_b, NULL);
1557 difference = chrec_fold_minus (type, chrec_a, chrec_b);
1559 switch (TREE_CODE (difference))
1562 if (integer_zerop (difference))
1564 /* The difference is equal to zero: the accessed index
1565 overlaps for each iteration in the loop. */
1566 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1567 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
1568 *last_conflicts = chrec_dont_know;
1569 dependence_stats.num_ziv_dependent++;
1573 /* The accesses do not overlap. */
1574 *overlaps_a = conflict_fn_no_dependence ();
1575 *overlaps_b = conflict_fn_no_dependence ();
1576 *last_conflicts = integer_zero_node;
1577 dependence_stats.num_ziv_independent++;
1582 /* We're not sure whether the indexes overlap. For the moment,
1583 conservatively answer "don't know". */
1584 if (dump_file && (dump_flags & TDF_DETAILS))
1585 fprintf (dump_file, "ziv test failed: difference is non-integer.\n");
1587 *overlaps_a = conflict_fn_not_known ();
1588 *overlaps_b = conflict_fn_not_known ();
1589 *last_conflicts = chrec_dont_know;
1590 dependence_stats.num_ziv_unimplemented++;
1594 if (dump_file && (dump_flags & TDF_DETAILS))
1595 fprintf (dump_file, ")\n");
1598 /* Sets NIT to the estimated number of executions of the statements in
1599 LOOP. If CONSERVATIVE is true, we must be sure that NIT is at least as
1600 large as the number of iterations. If we have no reliable estimate,
1601 the function returns false, otherwise returns true. */
1604 estimated_loop_iterations (struct loop *loop, bool conservative,
1607 estimate_numbers_of_iterations_loop (loop);
1610 if (!loop->any_upper_bound)
1613 *nit = loop->nb_iterations_upper_bound;
1617 if (!loop->any_estimate)
1620 *nit = loop->nb_iterations_estimate;
1626 /* Similar to estimated_loop_iterations, but returns the estimate only
1627 if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
1628 on the number of iterations of LOOP could not be derived, returns -1. */
1631 estimated_loop_iterations_int (struct loop *loop, bool conservative)
1634 HOST_WIDE_INT hwi_nit;
1636 if (!estimated_loop_iterations (loop, conservative, &nit))
1639 if (!double_int_fits_in_shwi_p (nit))
1641 hwi_nit = double_int_to_shwi (nit);
1643 return hwi_nit < 0 ? -1 : hwi_nit;
1646 /* Similar to estimated_loop_iterations, but returns the estimate as a tree,
1647 and only if it fits to the int type. If this is not the case, or the
1648 estimate on the number of iterations of LOOP could not be derived, returns
1652 estimated_loop_iterations_tree (struct loop *loop, bool conservative)
1657 if (!estimated_loop_iterations (loop, conservative, &nit))
1658 return chrec_dont_know;
1660 type = lang_hooks.types.type_for_size (INT_TYPE_SIZE, true);
1661 if (!double_int_fits_to_tree_p (type, nit))
1662 return chrec_dont_know;
1664 return double_int_to_tree (type, nit);
1667 /* Analyze a SIV (Single Index Variable) subscript where CHREC_A is a
1668 constant, and CHREC_B is an affine function. *OVERLAPS_A and
1669 *OVERLAPS_B are initialized to the functions that describe the
1670 relation between the elements accessed twice by CHREC_A and
1671 CHREC_B. For k >= 0, the following property is verified:
1673 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1676 analyze_siv_subscript_cst_affine (tree chrec_a,
1678 conflict_function **overlaps_a,
1679 conflict_function **overlaps_b,
1680 tree *last_conflicts)
1682 bool value0, value1, value2;
1683 tree type, difference, tmp;
1685 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1686 chrec_a = chrec_convert (type, chrec_a, NULL);
1687 chrec_b = chrec_convert (type, chrec_b, NULL);
1688 difference = chrec_fold_minus (type, initial_condition (chrec_b), chrec_a);
1690 if (!chrec_is_positive (initial_condition (difference), &value0))
1692 if (dump_file && (dump_flags & TDF_DETAILS))
1693 fprintf (dump_file, "siv test failed: chrec is not positive.\n");
1695 dependence_stats.num_siv_unimplemented++;
1696 *overlaps_a = conflict_fn_not_known ();
1697 *overlaps_b = conflict_fn_not_known ();
1698 *last_conflicts = chrec_dont_know;
1703 if (value0 == false)
1705 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value1))
1707 if (dump_file && (dump_flags & TDF_DETAILS))
1708 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1710 *overlaps_a = conflict_fn_not_known ();
1711 *overlaps_b = conflict_fn_not_known ();
1712 *last_conflicts = chrec_dont_know;
1713 dependence_stats.num_siv_unimplemented++;
1722 chrec_b = {10, +, 1}
1725 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1727 HOST_WIDE_INT numiter;
1728 struct loop *loop = get_chrec_loop (chrec_b);
1730 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1731 tmp = fold_build2 (EXACT_DIV_EXPR, type,
1732 fold_build1 (ABS_EXPR, type, difference),
1733 CHREC_RIGHT (chrec_b));
1734 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1735 *last_conflicts = integer_one_node;
1738 /* Perform weak-zero siv test to see if overlap is
1739 outside the loop bounds. */
1740 numiter = estimated_loop_iterations_int (loop, false);
1743 && compare_tree_int (tmp, numiter) > 0)
1745 free_conflict_function (*overlaps_a);
1746 free_conflict_function (*overlaps_b);
1747 *overlaps_a = conflict_fn_no_dependence ();
1748 *overlaps_b = conflict_fn_no_dependence ();
1749 *last_conflicts = integer_zero_node;
1750 dependence_stats.num_siv_independent++;
1753 dependence_stats.num_siv_dependent++;
1757 /* When the step does not divide the difference, there are
1761 *overlaps_a = conflict_fn_no_dependence ();
1762 *overlaps_b = conflict_fn_no_dependence ();
1763 *last_conflicts = integer_zero_node;
1764 dependence_stats.num_siv_independent++;
1773 chrec_b = {10, +, -1}
1775 In this case, chrec_a will not overlap with chrec_b. */
1776 *overlaps_a = conflict_fn_no_dependence ();
1777 *overlaps_b = conflict_fn_no_dependence ();
1778 *last_conflicts = integer_zero_node;
1779 dependence_stats.num_siv_independent++;
1786 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value2))
1788 if (dump_file && (dump_flags & TDF_DETAILS))
1789 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1791 *overlaps_a = conflict_fn_not_known ();
1792 *overlaps_b = conflict_fn_not_known ();
1793 *last_conflicts = chrec_dont_know;
1794 dependence_stats.num_siv_unimplemented++;
1799 if (value2 == false)
1803 chrec_b = {10, +, -1}
1805 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1807 HOST_WIDE_INT numiter;
1808 struct loop *loop = get_chrec_loop (chrec_b);
1810 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1811 tmp = fold_build2 (EXACT_DIV_EXPR, type, difference,
1812 CHREC_RIGHT (chrec_b));
1813 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1814 *last_conflicts = integer_one_node;
1816 /* Perform weak-zero siv test to see if overlap is
1817 outside the loop bounds. */
1818 numiter = estimated_loop_iterations_int (loop, false);
1821 && compare_tree_int (tmp, numiter) > 0)
1823 free_conflict_function (*overlaps_a);
1824 free_conflict_function (*overlaps_b);
1825 *overlaps_a = conflict_fn_no_dependence ();
1826 *overlaps_b = conflict_fn_no_dependence ();
1827 *last_conflicts = integer_zero_node;
1828 dependence_stats.num_siv_independent++;
1831 dependence_stats.num_siv_dependent++;
1835 /* When the step does not divide the difference, there
1839 *overlaps_a = conflict_fn_no_dependence ();
1840 *overlaps_b = conflict_fn_no_dependence ();
1841 *last_conflicts = integer_zero_node;
1842 dependence_stats.num_siv_independent++;
1852 In this case, chrec_a will not overlap with chrec_b. */
1853 *overlaps_a = conflict_fn_no_dependence ();
1854 *overlaps_b = conflict_fn_no_dependence ();
1855 *last_conflicts = integer_zero_node;
1856 dependence_stats.num_siv_independent++;
1864 /* Helper recursive function for initializing the matrix A. Returns
1865 the initial value of CHREC. */
1868 initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
1872 switch (TREE_CODE (chrec))
1874 case POLYNOMIAL_CHREC:
1875 gcc_assert (TREE_CODE (CHREC_RIGHT (chrec)) == INTEGER_CST);
1877 A[index][0] = mult * int_cst_value (CHREC_RIGHT (chrec));
1878 return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult);
1884 tree op0 = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1885 tree op1 = initialize_matrix_A (A, TREE_OPERAND (chrec, 1), index, mult);
1887 return chrec_fold_op (TREE_CODE (chrec), chrec_type (chrec), op0, op1);
1892 tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1893 return chrec_convert (chrec_type (chrec), op, NULL);
1905 #define FLOOR_DIV(x,y) ((x) / (y))
1907 /* Solves the special case of the Diophantine equation:
1908 | {0, +, STEP_A}_x (OVERLAPS_A) = {0, +, STEP_B}_y (OVERLAPS_B)
1910 Computes the descriptions OVERLAPS_A and OVERLAPS_B. NITER is the
1911 number of iterations that loops X and Y run. The overlaps will be
1912 constructed as evolutions in dimension DIM. */
1915 compute_overlap_steps_for_affine_univar (int niter, int step_a, int step_b,
1916 affine_fn *overlaps_a,
1917 affine_fn *overlaps_b,
1918 tree *last_conflicts, int dim)
1920 if (((step_a > 0 && step_b > 0)
1921 || (step_a < 0 && step_b < 0)))
1923 int step_overlaps_a, step_overlaps_b;
1924 int gcd_steps_a_b, last_conflict, tau2;
1926 gcd_steps_a_b = gcd (step_a, step_b);
1927 step_overlaps_a = step_b / gcd_steps_a_b;
1928 step_overlaps_b = step_a / gcd_steps_a_b;
1932 tau2 = FLOOR_DIV (niter, step_overlaps_a);
1933 tau2 = MIN (tau2, FLOOR_DIV (niter, step_overlaps_b));
1934 last_conflict = tau2;
1935 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
1938 *last_conflicts = chrec_dont_know;
1940 *overlaps_a = affine_fn_univar (integer_zero_node, dim,
1941 build_int_cst (NULL_TREE,
1943 *overlaps_b = affine_fn_univar (integer_zero_node, dim,
1944 build_int_cst (NULL_TREE,
1950 *overlaps_a = affine_fn_cst (integer_zero_node);
1951 *overlaps_b = affine_fn_cst (integer_zero_node);
1952 *last_conflicts = integer_zero_node;
1956 /* Solves the special case of a Diophantine equation where CHREC_A is
1957 an affine bivariate function, and CHREC_B is an affine univariate
1958 function. For example,
1960 | {{0, +, 1}_x, +, 1335}_y = {0, +, 1336}_z
1962 has the following overlapping functions:
1964 | x (t, u, v) = {{0, +, 1336}_t, +, 1}_v
1965 | y (t, u, v) = {{0, +, 1336}_u, +, 1}_v
1966 | z (t, u, v) = {{{0, +, 1}_t, +, 1335}_u, +, 1}_v
1968 FORNOW: This is a specialized implementation for a case occurring in
1969 a common benchmark. Implement the general algorithm. */
1972 compute_overlap_steps_for_affine_1_2 (tree chrec_a, tree chrec_b,
1973 conflict_function **overlaps_a,
1974 conflict_function **overlaps_b,
1975 tree *last_conflicts)
1977 bool xz_p, yz_p, xyz_p;
1978 int step_x, step_y, step_z;
1979 HOST_WIDE_INT niter_x, niter_y, niter_z, niter;
1980 affine_fn overlaps_a_xz, overlaps_b_xz;
1981 affine_fn overlaps_a_yz, overlaps_b_yz;
1982 affine_fn overlaps_a_xyz, overlaps_b_xyz;
1983 affine_fn ova1, ova2, ovb;
1984 tree last_conflicts_xz, last_conflicts_yz, last_conflicts_xyz;
1986 step_x = int_cst_value (CHREC_RIGHT (CHREC_LEFT (chrec_a)));
1987 step_y = int_cst_value (CHREC_RIGHT (chrec_a));
1988 step_z = int_cst_value (CHREC_RIGHT (chrec_b));
1991 estimated_loop_iterations_int (get_chrec_loop (CHREC_LEFT (chrec_a)),
1993 niter_y = estimated_loop_iterations_int (get_chrec_loop (chrec_a), false);
1994 niter_z = estimated_loop_iterations_int (get_chrec_loop (chrec_b), false);
1996 if (niter_x < 0 || niter_y < 0 || niter_z < 0)
1998 if (dump_file && (dump_flags & TDF_DETAILS))
1999 fprintf (dump_file, "overlap steps test failed: no iteration counts.\n");
2001 *overlaps_a = conflict_fn_not_known ();
2002 *overlaps_b = conflict_fn_not_known ();
2003 *last_conflicts = chrec_dont_know;
2007 niter = MIN (niter_x, niter_z);
2008 compute_overlap_steps_for_affine_univar (niter, step_x, step_z,
2011 &last_conflicts_xz, 1);
2012 niter = MIN (niter_y, niter_z);
2013 compute_overlap_steps_for_affine_univar (niter, step_y, step_z,
2016 &last_conflicts_yz, 2);
2017 niter = MIN (niter_x, niter_z);
2018 niter = MIN (niter_y, niter);
2019 compute_overlap_steps_for_affine_univar (niter, step_x + step_y, step_z,
2022 &last_conflicts_xyz, 3);
2024 xz_p = !integer_zerop (last_conflicts_xz);
2025 yz_p = !integer_zerop (last_conflicts_yz);
2026 xyz_p = !integer_zerop (last_conflicts_xyz);
2028 if (xz_p || yz_p || xyz_p)
2030 ova1 = affine_fn_cst (integer_zero_node);
2031 ova2 = affine_fn_cst (integer_zero_node);
2032 ovb = affine_fn_cst (integer_zero_node);
2035 affine_fn t0 = ova1;
2038 ova1 = affine_fn_plus (ova1, overlaps_a_xz);
2039 ovb = affine_fn_plus (ovb, overlaps_b_xz);
2040 affine_fn_free (t0);
2041 affine_fn_free (t2);
2042 *last_conflicts = last_conflicts_xz;
2046 affine_fn t0 = ova2;
2049 ova2 = affine_fn_plus (ova2, overlaps_a_yz);
2050 ovb = affine_fn_plus (ovb, overlaps_b_yz);
2051 affine_fn_free (t0);
2052 affine_fn_free (t2);
2053 *last_conflicts = last_conflicts_yz;
2057 affine_fn t0 = ova1;
2058 affine_fn t2 = ova2;
2061 ova1 = affine_fn_plus (ova1, overlaps_a_xyz);
2062 ova2 = affine_fn_plus (ova2, overlaps_a_xyz);
2063 ovb = affine_fn_plus (ovb, overlaps_b_xyz);
2064 affine_fn_free (t0);
2065 affine_fn_free (t2);
2066 affine_fn_free (t4);
2067 *last_conflicts = last_conflicts_xyz;
2069 *overlaps_a = conflict_fn (2, ova1, ova2);
2070 *overlaps_b = conflict_fn (1, ovb);
2074 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2075 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2076 *last_conflicts = integer_zero_node;
2079 affine_fn_free (overlaps_a_xz);
2080 affine_fn_free (overlaps_b_xz);
2081 affine_fn_free (overlaps_a_yz);
2082 affine_fn_free (overlaps_b_yz);
2083 affine_fn_free (overlaps_a_xyz);
2084 affine_fn_free (overlaps_b_xyz);
2087 /* Determines the overlapping elements due to accesses CHREC_A and
2088 CHREC_B, that are affine functions. This function cannot handle
2089 symbolic evolution functions, ie. when initial conditions are
2090 parameters, because it uses lambda matrices of integers. */
2093 analyze_subscript_affine_affine (tree chrec_a,
2095 conflict_function **overlaps_a,
2096 conflict_function **overlaps_b,
2097 tree *last_conflicts)
2099 unsigned nb_vars_a, nb_vars_b, dim;
2100 HOST_WIDE_INT init_a, init_b, gamma, gcd_alpha_beta;
2101 lambda_matrix A, U, S;
2103 if (eq_evolutions_p (chrec_a, chrec_b))
2105 /* The accessed index overlaps for each iteration in the
2107 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2108 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2109 *last_conflicts = chrec_dont_know;
2112 if (dump_file && (dump_flags & TDF_DETAILS))
2113 fprintf (dump_file, "(analyze_subscript_affine_affine \n");
2115 /* For determining the initial intersection, we have to solve a
2116 Diophantine equation. This is the most time consuming part.
2118 For answering to the question: "Is there a dependence?" we have
2119 to prove that there exists a solution to the Diophantine
2120 equation, and that the solution is in the iteration domain,
2121 i.e. the solution is positive or zero, and that the solution
2122 happens before the upper bound loop.nb_iterations. Otherwise
2123 there is no dependence. This function outputs a description of
2124 the iterations that hold the intersections. */
2126 nb_vars_a = nb_vars_in_chrec (chrec_a);
2127 nb_vars_b = nb_vars_in_chrec (chrec_b);
2129 dim = nb_vars_a + nb_vars_b;
2130 U = lambda_matrix_new (dim, dim);
2131 A = lambda_matrix_new (dim, 1);
2132 S = lambda_matrix_new (dim, 1);
2134 init_a = int_cst_value (initialize_matrix_A (A, chrec_a, 0, 1));
2135 init_b = int_cst_value (initialize_matrix_A (A, chrec_b, nb_vars_a, -1));
2136 gamma = init_b - init_a;
2138 /* Don't do all the hard work of solving the Diophantine equation
2139 when we already know the solution: for example,
2142 | gamma = 3 - 3 = 0.
2143 Then the first overlap occurs during the first iterations:
2144 | {3, +, 1}_1 ({0, +, 4}_x) = {3, +, 4}_2 ({0, +, 1}_x)
2148 if (nb_vars_a == 1 && nb_vars_b == 1)
2150 HOST_WIDE_INT step_a, step_b;
2151 HOST_WIDE_INT niter, niter_a, niter_b;
2154 niter_a = estimated_loop_iterations_int (get_chrec_loop (chrec_a),
2156 niter_b = estimated_loop_iterations_int (get_chrec_loop (chrec_b),
2158 niter = MIN (niter_a, niter_b);
2159 step_a = int_cst_value (CHREC_RIGHT (chrec_a));
2160 step_b = int_cst_value (CHREC_RIGHT (chrec_b));
2162 compute_overlap_steps_for_affine_univar (niter, step_a, step_b,
2165 *overlaps_a = conflict_fn (1, ova);
2166 *overlaps_b = conflict_fn (1, ovb);
2169 else if (nb_vars_a == 2 && nb_vars_b == 1)
2170 compute_overlap_steps_for_affine_1_2
2171 (chrec_a, chrec_b, overlaps_a, overlaps_b, last_conflicts);
2173 else if (nb_vars_a == 1 && nb_vars_b == 2)
2174 compute_overlap_steps_for_affine_1_2
2175 (chrec_b, chrec_a, overlaps_b, overlaps_a, last_conflicts);
2179 if (dump_file && (dump_flags & TDF_DETAILS))
2180 fprintf (dump_file, "affine-affine test failed: too many variables.\n");
2181 *overlaps_a = conflict_fn_not_known ();
2182 *overlaps_b = conflict_fn_not_known ();
2183 *last_conflicts = chrec_dont_know;
2185 goto end_analyze_subs_aa;
2189 lambda_matrix_right_hermite (A, dim, 1, S, U);
2194 lambda_matrix_row_negate (U, dim, 0);
2196 gcd_alpha_beta = S[0][0];
2198 /* Something went wrong: for example in {1, +, 0}_5 vs. {0, +, 0}_5,
2199 but that is a quite strange case. Instead of ICEing, answer
2201 if (gcd_alpha_beta == 0)
2203 *overlaps_a = conflict_fn_not_known ();
2204 *overlaps_b = conflict_fn_not_known ();
2205 *last_conflicts = chrec_dont_know;
2206 goto end_analyze_subs_aa;
2209 /* The classic "gcd-test". */
2210 if (!int_divides_p (gcd_alpha_beta, gamma))
2212 /* The "gcd-test" has determined that there is no integer
2213 solution, i.e. there is no dependence. */
2214 *overlaps_a = conflict_fn_no_dependence ();
2215 *overlaps_b = conflict_fn_no_dependence ();
2216 *last_conflicts = integer_zero_node;
2219 /* Both access functions are univariate. This includes SIV and MIV cases. */
2220 else if (nb_vars_a == 1 && nb_vars_b == 1)
2222 /* Both functions should have the same evolution sign. */
2223 if (((A[0][0] > 0 && -A[1][0] > 0)
2224 || (A[0][0] < 0 && -A[1][0] < 0)))
2226 /* The solutions are given by:
2228 | [GAMMA/GCD_ALPHA_BETA t].[u11 u12] = [x0]
2231 For a given integer t. Using the following variables,
2233 | i0 = u11 * gamma / gcd_alpha_beta
2234 | j0 = u12 * gamma / gcd_alpha_beta
2241 | y0 = j0 + j1 * t. */
2242 HOST_WIDE_INT i0, j0, i1, j1;
2244 i0 = U[0][0] * gamma / gcd_alpha_beta;
2245 j0 = U[0][1] * gamma / gcd_alpha_beta;
2249 if ((i1 == 0 && i0 < 0)
2250 || (j1 == 0 && j0 < 0))
2252 /* There is no solution.
2253 FIXME: The case "i0 > nb_iterations, j0 > nb_iterations"
2254 falls in here, but for the moment we don't look at the
2255 upper bound of the iteration domain. */
2256 *overlaps_a = conflict_fn_no_dependence ();
2257 *overlaps_b = conflict_fn_no_dependence ();
2258 *last_conflicts = integer_zero_node;
2259 goto end_analyze_subs_aa;
2262 if (i1 > 0 && j1 > 0)
2264 HOST_WIDE_INT niter_a = estimated_loop_iterations_int
2265 (get_chrec_loop (chrec_a), false);
2266 HOST_WIDE_INT niter_b = estimated_loop_iterations_int
2267 (get_chrec_loop (chrec_b), false);
2268 HOST_WIDE_INT niter = MIN (niter_a, niter_b);
2270 /* (X0, Y0) is a solution of the Diophantine equation:
2271 "chrec_a (X0) = chrec_b (Y0)". */
2272 HOST_WIDE_INT tau1 = MAX (CEIL (-i0, i1),
2274 HOST_WIDE_INT x0 = i1 * tau1 + i0;
2275 HOST_WIDE_INT y0 = j1 * tau1 + j0;
2277 /* (X1, Y1) is the smallest positive solution of the eq
2278 "chrec_a (X1) = chrec_b (Y1)", i.e. this is where the
2279 first conflict occurs. */
2280 HOST_WIDE_INT min_multiple = MIN (x0 / i1, y0 / j1);
2281 HOST_WIDE_INT x1 = x0 - i1 * min_multiple;
2282 HOST_WIDE_INT y1 = y0 - j1 * min_multiple;
2286 HOST_WIDE_INT tau2 = MIN (FLOOR_DIV (niter - i0, i1),
2287 FLOOR_DIV (niter - j0, j1));
2288 HOST_WIDE_INT last_conflict = tau2 - (x1 - i0)/i1;
2290 /* If the overlap occurs outside of the bounds of the
2291 loop, there is no dependence. */
2292 if (x1 > niter || y1 > niter)
2294 *overlaps_a = conflict_fn_no_dependence ();
2295 *overlaps_b = conflict_fn_no_dependence ();
2296 *last_conflicts = integer_zero_node;
2297 goto end_analyze_subs_aa;
2300 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
2303 *last_conflicts = chrec_dont_know;
2307 affine_fn_univar (build_int_cst (NULL_TREE, x1),
2309 build_int_cst (NULL_TREE, i1)));
2312 affine_fn_univar (build_int_cst (NULL_TREE, y1),
2314 build_int_cst (NULL_TREE, j1)));
2318 /* FIXME: For the moment, the upper bound of the
2319 iteration domain for i and j is not checked. */
2320 if (dump_file && (dump_flags & TDF_DETAILS))
2321 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2322 *overlaps_a = conflict_fn_not_known ();
2323 *overlaps_b = conflict_fn_not_known ();
2324 *last_conflicts = chrec_dont_know;
2329 if (dump_file && (dump_flags & TDF_DETAILS))
2330 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2331 *overlaps_a = conflict_fn_not_known ();
2332 *overlaps_b = conflict_fn_not_known ();
2333 *last_conflicts = chrec_dont_know;
2338 if (dump_file && (dump_flags & TDF_DETAILS))
2339 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2340 *overlaps_a = conflict_fn_not_known ();
2341 *overlaps_b = conflict_fn_not_known ();
2342 *last_conflicts = chrec_dont_know;
2345 end_analyze_subs_aa:
2346 if (dump_file && (dump_flags & TDF_DETAILS))
2348 fprintf (dump_file, " (overlaps_a = ");
2349 dump_conflict_function (dump_file, *overlaps_a);
2350 fprintf (dump_file, ")\n (overlaps_b = ");
2351 dump_conflict_function (dump_file, *overlaps_b);
2352 fprintf (dump_file, ")\n");
2353 fprintf (dump_file, ")\n");
2357 /* Returns true when analyze_subscript_affine_affine can be used for
2358 determining the dependence relation between chrec_a and chrec_b,
2359 that contain symbols. This function modifies chrec_a and chrec_b
2360 such that the analysis result is the same, and such that they don't
2361 contain symbols, and then can safely be passed to the analyzer.
2363 Example: The analysis of the following tuples of evolutions produce
2364 the same results: {x+1, +, 1}_1 vs. {x+3, +, 1}_1, and {-2, +, 1}_1
2367 {x+1, +, 1}_1 ({2, +, 1}_1) = {x+3, +, 1}_1 ({0, +, 1}_1)
2368 {-2, +, 1}_1 ({2, +, 1}_1) = {0, +, 1}_1 ({0, +, 1}_1)
2372 can_use_analyze_subscript_affine_affine (tree *chrec_a, tree *chrec_b)
2374 tree diff, type, left_a, left_b, right_b;
2376 if (chrec_contains_symbols (CHREC_RIGHT (*chrec_a))
2377 || chrec_contains_symbols (CHREC_RIGHT (*chrec_b)))
2378 /* FIXME: For the moment not handled. Might be refined later. */
2381 type = chrec_type (*chrec_a);
2382 left_a = CHREC_LEFT (*chrec_a);
2383 left_b = chrec_convert (type, CHREC_LEFT (*chrec_b), NULL);
2384 diff = chrec_fold_minus (type, left_a, left_b);
2386 if (!evolution_function_is_constant_p (diff))
2389 if (dump_file && (dump_flags & TDF_DETAILS))
2390 fprintf (dump_file, "can_use_subscript_aff_aff_for_symbolic \n");
2392 *chrec_a = build_polynomial_chrec (CHREC_VARIABLE (*chrec_a),
2393 diff, CHREC_RIGHT (*chrec_a));
2394 right_b = chrec_convert (type, CHREC_RIGHT (*chrec_b), NULL);
2395 *chrec_b = build_polynomial_chrec (CHREC_VARIABLE (*chrec_b),
2396 build_int_cst (type, 0),
2401 /* Analyze a SIV (Single Index Variable) subscript. *OVERLAPS_A and
2402 *OVERLAPS_B are initialized to the functions that describe the
2403 relation between the elements accessed twice by CHREC_A and
2404 CHREC_B. For k >= 0, the following property is verified:
2406 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2409 analyze_siv_subscript (tree chrec_a,
2411 conflict_function **overlaps_a,
2412 conflict_function **overlaps_b,
2413 tree *last_conflicts,
2416 dependence_stats.num_siv++;
2418 if (dump_file && (dump_flags & TDF_DETAILS))
2419 fprintf (dump_file, "(analyze_siv_subscript \n");
2421 if (evolution_function_is_constant_p (chrec_a)
2422 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2423 analyze_siv_subscript_cst_affine (chrec_a, chrec_b,
2424 overlaps_a, overlaps_b, last_conflicts);
2426 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2427 && evolution_function_is_constant_p (chrec_b))
2428 analyze_siv_subscript_cst_affine (chrec_b, chrec_a,
2429 overlaps_b, overlaps_a, last_conflicts);
2431 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2432 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2434 if (!chrec_contains_symbols (chrec_a)
2435 && !chrec_contains_symbols (chrec_b))
2437 analyze_subscript_affine_affine (chrec_a, chrec_b,
2438 overlaps_a, overlaps_b,
2441 if (CF_NOT_KNOWN_P (*overlaps_a)
2442 || CF_NOT_KNOWN_P (*overlaps_b))
2443 dependence_stats.num_siv_unimplemented++;
2444 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2445 || CF_NO_DEPENDENCE_P (*overlaps_b))
2446 dependence_stats.num_siv_independent++;
2448 dependence_stats.num_siv_dependent++;
2450 else if (can_use_analyze_subscript_affine_affine (&chrec_a,
2453 analyze_subscript_affine_affine (chrec_a, chrec_b,
2454 overlaps_a, overlaps_b,
2457 if (CF_NOT_KNOWN_P (*overlaps_a)
2458 || CF_NOT_KNOWN_P (*overlaps_b))
2459 dependence_stats.num_siv_unimplemented++;
2460 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2461 || CF_NO_DEPENDENCE_P (*overlaps_b))
2462 dependence_stats.num_siv_independent++;
2464 dependence_stats.num_siv_dependent++;
2467 goto siv_subscript_dontknow;
2472 siv_subscript_dontknow:;
2473 if (dump_file && (dump_flags & TDF_DETAILS))
2474 fprintf (dump_file, "siv test failed: unimplemented.\n");
2475 *overlaps_a = conflict_fn_not_known ();
2476 *overlaps_b = conflict_fn_not_known ();
2477 *last_conflicts = chrec_dont_know;
2478 dependence_stats.num_siv_unimplemented++;
2481 if (dump_file && (dump_flags & TDF_DETAILS))
2482 fprintf (dump_file, ")\n");
2485 /* Returns false if we can prove that the greatest common divisor of the steps
2486 of CHREC does not divide CST, false otherwise. */
2489 gcd_of_steps_may_divide_p (const_tree chrec, const_tree cst)
2491 HOST_WIDE_INT cd = 0, val;
2494 if (!host_integerp (cst, 0))
2496 val = tree_low_cst (cst, 0);
2498 while (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
2500 step = CHREC_RIGHT (chrec);
2501 if (!host_integerp (step, 0))
2503 cd = gcd (cd, tree_low_cst (step, 0));
2504 chrec = CHREC_LEFT (chrec);
2507 return val % cd == 0;
2510 /* Analyze a MIV (Multiple Index Variable) subscript with respect to
2511 LOOP_NEST. *OVERLAPS_A and *OVERLAPS_B are initialized to the
2512 functions that describe the relation between the elements accessed
2513 twice by CHREC_A and CHREC_B. For k >= 0, the following property
2516 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2519 analyze_miv_subscript (tree chrec_a,
2521 conflict_function **overlaps_a,
2522 conflict_function **overlaps_b,
2523 tree *last_conflicts,
2524 struct loop *loop_nest)
2526 /* FIXME: This is a MIV subscript, not yet handled.
2527 Example: (A[{1, +, 1}_1] vs. A[{1, +, 1}_2]) that comes from
2530 In the SIV test we had to solve a Diophantine equation with two
2531 variables. In the MIV case we have to solve a Diophantine
2532 equation with 2*n variables (if the subscript uses n IVs).
2534 tree type, difference;
2536 dependence_stats.num_miv++;
2537 if (dump_file && (dump_flags & TDF_DETAILS))
2538 fprintf (dump_file, "(analyze_miv_subscript \n");
2540 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
2541 chrec_a = chrec_convert (type, chrec_a, NULL);
2542 chrec_b = chrec_convert (type, chrec_b, NULL);
2543 difference = chrec_fold_minus (type, chrec_a, chrec_b);
2545 if (eq_evolutions_p (chrec_a, chrec_b))
2547 /* Access functions are the same: all the elements are accessed
2548 in the same order. */
2549 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2550 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2551 *last_conflicts = estimated_loop_iterations_tree
2552 (get_chrec_loop (chrec_a), true);
2553 dependence_stats.num_miv_dependent++;
2556 else if (evolution_function_is_constant_p (difference)
2557 /* For the moment, the following is verified:
2558 evolution_function_is_affine_multivariate_p (chrec_a,
2560 && !gcd_of_steps_may_divide_p (chrec_a, difference))
2562 /* testsuite/.../ssa-chrec-33.c
2563 {{21, +, 2}_1, +, -2}_2 vs. {{20, +, 2}_1, +, -2}_2
2565 The difference is 1, and all the evolution steps are multiples
2566 of 2, consequently there are no overlapping elements. */
2567 *overlaps_a = conflict_fn_no_dependence ();
2568 *overlaps_b = conflict_fn_no_dependence ();
2569 *last_conflicts = integer_zero_node;
2570 dependence_stats.num_miv_independent++;
2573 else if (evolution_function_is_affine_multivariate_p (chrec_a, loop_nest->num)
2574 && !chrec_contains_symbols (chrec_a)
2575 && evolution_function_is_affine_multivariate_p (chrec_b, loop_nest->num)
2576 && !chrec_contains_symbols (chrec_b))
2578 /* testsuite/.../ssa-chrec-35.c
2579 {0, +, 1}_2 vs. {0, +, 1}_3
2580 the overlapping elements are respectively located at iterations:
2581 {0, +, 1}_x and {0, +, 1}_x,
2582 in other words, we have the equality:
2583 {0, +, 1}_2 ({0, +, 1}_x) = {0, +, 1}_3 ({0, +, 1}_x)
2586 {{0, +, 1}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y) =
2587 {0, +, 1}_1 ({{0, +, 1}_x, +, 2}_y)
2589 {{0, +, 2}_1, +, 3}_2 ({0, +, 1}_y, {0, +, 1}_x) =
2590 {{0, +, 3}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y)
2592 analyze_subscript_affine_affine (chrec_a, chrec_b,
2593 overlaps_a, overlaps_b, last_conflicts);
2595 if (CF_NOT_KNOWN_P (*overlaps_a)
2596 || CF_NOT_KNOWN_P (*overlaps_b))
2597 dependence_stats.num_miv_unimplemented++;
2598 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2599 || CF_NO_DEPENDENCE_P (*overlaps_b))
2600 dependence_stats.num_miv_independent++;
2602 dependence_stats.num_miv_dependent++;
2607 /* When the analysis is too difficult, answer "don't know". */
2608 if (dump_file && (dump_flags & TDF_DETAILS))
2609 fprintf (dump_file, "analyze_miv_subscript test failed: unimplemented.\n");
2611 *overlaps_a = conflict_fn_not_known ();
2612 *overlaps_b = conflict_fn_not_known ();
2613 *last_conflicts = chrec_dont_know;
2614 dependence_stats.num_miv_unimplemented++;
2617 if (dump_file && (dump_flags & TDF_DETAILS))
2618 fprintf (dump_file, ")\n");
2621 /* Determines the iterations for which CHREC_A is equal to CHREC_B in
2622 with respect to LOOP_NEST. OVERLAP_ITERATIONS_A and
2623 OVERLAP_ITERATIONS_B are initialized with two functions that
2624 describe the iterations that contain conflicting elements.
2626 Remark: For an integer k >= 0, the following equality is true:
2628 CHREC_A (OVERLAP_ITERATIONS_A (k)) == CHREC_B (OVERLAP_ITERATIONS_B (k)).
2632 analyze_overlapping_iterations (tree chrec_a,
2634 conflict_function **overlap_iterations_a,
2635 conflict_function **overlap_iterations_b,
2636 tree *last_conflicts, struct loop *loop_nest)
2638 unsigned int lnn = loop_nest->num;
2640 dependence_stats.num_subscript_tests++;
2642 if (dump_file && (dump_flags & TDF_DETAILS))
2644 fprintf (dump_file, "(analyze_overlapping_iterations \n");
2645 fprintf (dump_file, " (chrec_a = ");
2646 print_generic_expr (dump_file, chrec_a, 0);
2647 fprintf (dump_file, ")\n (chrec_b = ");
2648 print_generic_expr (dump_file, chrec_b, 0);
2649 fprintf (dump_file, ")\n");
2652 if (chrec_a == NULL_TREE
2653 || chrec_b == NULL_TREE
2654 || chrec_contains_undetermined (chrec_a)
2655 || chrec_contains_undetermined (chrec_b))
2657 dependence_stats.num_subscript_undetermined++;
2659 *overlap_iterations_a = conflict_fn_not_known ();
2660 *overlap_iterations_b = conflict_fn_not_known ();
2663 /* If they are the same chrec, and are affine, they overlap
2664 on every iteration. */
2665 else if (eq_evolutions_p (chrec_a, chrec_b)
2666 && evolution_function_is_affine_multivariate_p (chrec_a, lnn))
2668 dependence_stats.num_same_subscript_function++;
2669 *overlap_iterations_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2670 *overlap_iterations_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2671 *last_conflicts = chrec_dont_know;
2674 /* If they aren't the same, and aren't affine, we can't do anything
2676 else if ((chrec_contains_symbols (chrec_a)
2677 || chrec_contains_symbols (chrec_b))
2678 && (!evolution_function_is_affine_multivariate_p (chrec_a, lnn)
2679 || !evolution_function_is_affine_multivariate_p (chrec_b, lnn)))
2681 dependence_stats.num_subscript_undetermined++;
2682 *overlap_iterations_a = conflict_fn_not_known ();
2683 *overlap_iterations_b = conflict_fn_not_known ();
2686 else if (ziv_subscript_p (chrec_a, chrec_b))
2687 analyze_ziv_subscript (chrec_a, chrec_b,
2688 overlap_iterations_a, overlap_iterations_b,
2691 else if (siv_subscript_p (chrec_a, chrec_b))
2692 analyze_siv_subscript (chrec_a, chrec_b,
2693 overlap_iterations_a, overlap_iterations_b,
2694 last_conflicts, lnn);
2697 analyze_miv_subscript (chrec_a, chrec_b,
2698 overlap_iterations_a, overlap_iterations_b,
2699 last_conflicts, loop_nest);
2701 if (dump_file && (dump_flags & TDF_DETAILS))
2703 fprintf (dump_file, " (overlap_iterations_a = ");
2704 dump_conflict_function (dump_file, *overlap_iterations_a);
2705 fprintf (dump_file, ")\n (overlap_iterations_b = ");
2706 dump_conflict_function (dump_file, *overlap_iterations_b);
2707 fprintf (dump_file, ")\n");
2708 fprintf (dump_file, ")\n");
2712 /* Helper function for uniquely inserting distance vectors. */
2715 save_dist_v (struct data_dependence_relation *ddr, lambda_vector dist_v)
2720 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, v); i++)
2721 if (lambda_vector_equal (v, dist_v, DDR_NB_LOOPS (ddr)))
2724 VEC_safe_push (lambda_vector, heap, DDR_DIST_VECTS (ddr), dist_v);
2727 /* Helper function for uniquely inserting direction vectors. */
2730 save_dir_v (struct data_dependence_relation *ddr, lambda_vector dir_v)
2735 for (i = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), i, v); i++)
2736 if (lambda_vector_equal (v, dir_v, DDR_NB_LOOPS (ddr)))
2739 VEC_safe_push (lambda_vector, heap, DDR_DIR_VECTS (ddr), dir_v);
2742 /* Add a distance of 1 on all the loops outer than INDEX. If we
2743 haven't yet determined a distance for this outer loop, push a new
2744 distance vector composed of the previous distance, and a distance
2745 of 1 for this outer loop. Example:
2753 Saved vectors are of the form (dist_in_1, dist_in_2). First, we
2754 save (0, 1), then we have to save (1, 0). */
2757 add_outer_distances (struct data_dependence_relation *ddr,
2758 lambda_vector dist_v, int index)
2760 /* For each outer loop where init_v is not set, the accesses are
2761 in dependence of distance 1 in the loop. */
2762 while (--index >= 0)
2764 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2765 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
2767 save_dist_v (ddr, save_v);
2771 /* Return false when fail to represent the data dependence as a
2772 distance vector. INIT_B is set to true when a component has been
2773 added to the distance vector DIST_V. INDEX_CARRY is then set to
2774 the index in DIST_V that carries the dependence. */
2777 build_classic_dist_vector_1 (struct data_dependence_relation *ddr,
2778 struct data_reference *ddr_a,
2779 struct data_reference *ddr_b,
2780 lambda_vector dist_v, bool *init_b,
2784 lambda_vector init_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2786 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2788 tree access_fn_a, access_fn_b;
2789 struct subscript *subscript = DDR_SUBSCRIPT (ddr, i);
2791 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2793 non_affine_dependence_relation (ddr);
2797 access_fn_a = DR_ACCESS_FN (ddr_a, i);
2798 access_fn_b = DR_ACCESS_FN (ddr_b, i);
2800 if (TREE_CODE (access_fn_a) == POLYNOMIAL_CHREC
2801 && TREE_CODE (access_fn_b) == POLYNOMIAL_CHREC)
2804 int index_a = index_in_loop_nest (CHREC_VARIABLE (access_fn_a),
2805 DDR_LOOP_NEST (ddr));
2806 int index_b = index_in_loop_nest (CHREC_VARIABLE (access_fn_b),
2807 DDR_LOOP_NEST (ddr));
2809 /* The dependence is carried by the outermost loop. Example:
2816 In this case, the dependence is carried by loop_1. */
2817 index = index_a < index_b ? index_a : index_b;
2818 *index_carry = MIN (index, *index_carry);
2820 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2822 non_affine_dependence_relation (ddr);
2826 dist = int_cst_value (SUB_DISTANCE (subscript));
2828 /* This is the subscript coupling test. If we have already
2829 recorded a distance for this loop (a distance coming from
2830 another subscript), it should be the same. For example,
2831 in the following code, there is no dependence:
2838 if (init_v[index] != 0 && dist_v[index] != dist)
2840 finalize_ddr_dependent (ddr, chrec_known);
2844 dist_v[index] = dist;
2848 else if (!operand_equal_p (access_fn_a, access_fn_b, 0))
2850 /* This can be for example an affine vs. constant dependence
2851 (T[i] vs. T[3]) that is not an affine dependence and is
2852 not representable as a distance vector. */
2853 non_affine_dependence_relation (ddr);
2861 /* Return true when the DDR contains only constant access functions. */
2864 constant_access_functions (const struct data_dependence_relation *ddr)
2868 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2869 if (!evolution_function_is_constant_p (DR_ACCESS_FN (DDR_A (ddr), i))
2870 || !evolution_function_is_constant_p (DR_ACCESS_FN (DDR_B (ddr), i)))
2876 /* Helper function for the case where DDR_A and DDR_B are the same
2877 multivariate access function with a constant step. For an example
2881 add_multivariate_self_dist (struct data_dependence_relation *ddr, tree c_2)
2884 tree c_1 = CHREC_LEFT (c_2);
2885 tree c_0 = CHREC_LEFT (c_1);
2886 lambda_vector dist_v;
2889 /* Polynomials with more than 2 variables are not handled yet. When
2890 the evolution steps are parameters, it is not possible to
2891 represent the dependence using classical distance vectors. */
2892 if (TREE_CODE (c_0) != INTEGER_CST
2893 || TREE_CODE (CHREC_RIGHT (c_1)) != INTEGER_CST
2894 || TREE_CODE (CHREC_RIGHT (c_2)) != INTEGER_CST)
2896 DDR_AFFINE_P (ddr) = false;
2900 x_2 = index_in_loop_nest (CHREC_VARIABLE (c_2), DDR_LOOP_NEST (ddr));
2901 x_1 = index_in_loop_nest (CHREC_VARIABLE (c_1), DDR_LOOP_NEST (ddr));
2903 /* For "{{0, +, 2}_1, +, 3}_2" the distance vector is (3, -2). */
2904 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2905 v1 = int_cst_value (CHREC_RIGHT (c_1));
2906 v2 = int_cst_value (CHREC_RIGHT (c_2));
2919 save_dist_v (ddr, dist_v);
2921 add_outer_distances (ddr, dist_v, x_1);
2924 /* Helper function for the case where DDR_A and DDR_B are the same
2925 access functions. */
2928 add_other_self_distances (struct data_dependence_relation *ddr)
2930 lambda_vector dist_v;
2932 int index_carry = DDR_NB_LOOPS (ddr);
2934 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2936 tree access_fun = DR_ACCESS_FN (DDR_A (ddr), i);
2938 if (TREE_CODE (access_fun) == POLYNOMIAL_CHREC)
2940 if (!evolution_function_is_univariate_p (access_fun))
2942 if (DDR_NUM_SUBSCRIPTS (ddr) != 1)
2944 DDR_ARE_DEPENDENT (ddr) = chrec_dont_know;
2948 access_fun = DR_ACCESS_FN (DDR_A (ddr), 0);
2950 if (TREE_CODE (CHREC_LEFT (access_fun)) == POLYNOMIAL_CHREC)
2951 add_multivariate_self_dist (ddr, access_fun);
2953 /* The evolution step is not constant: it varies in
2954 the outer loop, so this cannot be represented by a
2955 distance vector. For example in pr34635.c the
2956 evolution is {0, +, {0, +, 4}_1}_2. */
2957 DDR_AFFINE_P (ddr) = false;
2962 index_carry = MIN (index_carry,
2963 index_in_loop_nest (CHREC_VARIABLE (access_fun),
2964 DDR_LOOP_NEST (ddr)));
2968 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2969 add_outer_distances (ddr, dist_v, index_carry);
2973 insert_innermost_unit_dist_vector (struct data_dependence_relation *ddr)
2975 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2977 dist_v[DDR_INNER_LOOP (ddr)] = 1;
2978 save_dist_v (ddr, dist_v);
2981 /* Adds a unit distance vector to DDR when there is a 0 overlap. This
2982 is the case for example when access functions are the same and
2983 equal to a constant, as in:
2990 in which case the distance vectors are (0) and (1). */
2993 add_distance_for_zero_overlaps (struct data_dependence_relation *ddr)
2997 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2999 subscript_p sub = DDR_SUBSCRIPT (ddr, i);
3000 conflict_function *ca = SUB_CONFLICTS_IN_A (sub);
3001 conflict_function *cb = SUB_CONFLICTS_IN_B (sub);
3003 for (j = 0; j < ca->n; j++)
3004 if (affine_function_zero_p (ca->fns[j]))
3006 insert_innermost_unit_dist_vector (ddr);
3010 for (j = 0; j < cb->n; j++)
3011 if (affine_function_zero_p (cb->fns[j]))
3013 insert_innermost_unit_dist_vector (ddr);
3019 /* Compute the classic per loop distance vector. DDR is the data
3020 dependence relation to build a vector from. Return false when fail
3021 to represent the data dependence as a distance vector. */
3024 build_classic_dist_vector (struct data_dependence_relation *ddr,
3025 struct loop *loop_nest)
3027 bool init_b = false;
3028 int index_carry = DDR_NB_LOOPS (ddr);
3029 lambda_vector dist_v;
3031 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3034 if (same_access_functions (ddr))
3036 /* Save the 0 vector. */
3037 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3038 save_dist_v (ddr, dist_v);
3040 if (constant_access_functions (ddr))
3041 add_distance_for_zero_overlaps (ddr);
3043 if (DDR_NB_LOOPS (ddr) > 1)
3044 add_other_self_distances (ddr);
3049 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3050 if (!build_classic_dist_vector_1 (ddr, DDR_A (ddr), DDR_B (ddr),
3051 dist_v, &init_b, &index_carry))
3054 /* Save the distance vector if we initialized one. */
3057 /* Verify a basic constraint: classic distance vectors should
3058 always be lexicographically positive.
3060 Data references are collected in the order of execution of
3061 the program, thus for the following loop
3063 | for (i = 1; i < 100; i++)
3064 | for (j = 1; j < 100; j++)
3066 | t = T[j+1][i-1]; // A
3067 | T[j][i] = t + 2; // B
3070 references are collected following the direction of the wind:
3071 A then B. The data dependence tests are performed also
3072 following this order, such that we're looking at the distance
3073 separating the elements accessed by A from the elements later
3074 accessed by B. But in this example, the distance returned by
3075 test_dep (A, B) is lexicographically negative (-1, 1), that
3076 means that the access A occurs later than B with respect to
3077 the outer loop, ie. we're actually looking upwind. In this
3078 case we solve test_dep (B, A) looking downwind to the
3079 lexicographically positive solution, that returns the
3080 distance vector (1, -1). */
3081 if (!lambda_vector_lexico_pos (dist_v, DDR_NB_LOOPS (ddr)))
3083 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3084 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3087 compute_subscript_distance (ddr);
3088 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3089 save_v, &init_b, &index_carry))
3091 save_dist_v (ddr, save_v);
3092 DDR_REVERSED_P (ddr) = true;
3094 /* In this case there is a dependence forward for all the
3097 | for (k = 1; k < 100; k++)
3098 | for (i = 1; i < 100; i++)
3099 | for (j = 1; j < 100; j++)
3101 | t = T[j+1][i-1]; // A
3102 | T[j][i] = t + 2; // B
3110 if (DDR_NB_LOOPS (ddr) > 1)
3112 add_outer_distances (ddr, save_v, index_carry);
3113 add_outer_distances (ddr, dist_v, index_carry);
3118 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3119 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
3121 if (DDR_NB_LOOPS (ddr) > 1)
3123 lambda_vector opposite_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3125 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr),
3126 DDR_A (ddr), loop_nest))
3128 compute_subscript_distance (ddr);
3129 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3130 opposite_v, &init_b,
3134 save_dist_v (ddr, save_v);
3135 add_outer_distances (ddr, dist_v, index_carry);
3136 add_outer_distances (ddr, opposite_v, index_carry);
3139 save_dist_v (ddr, save_v);
3144 /* There is a distance of 1 on all the outer loops: Example:
3145 there is a dependence of distance 1 on loop_1 for the array A.
3151 add_outer_distances (ddr, dist_v,
3152 lambda_vector_first_nz (dist_v,
3153 DDR_NB_LOOPS (ddr), 0));
3156 if (dump_file && (dump_flags & TDF_DETAILS))
3160 fprintf (dump_file, "(build_classic_dist_vector\n");
3161 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3163 fprintf (dump_file, " dist_vector = (");
3164 print_lambda_vector (dump_file, DDR_DIST_VECT (ddr, i),
3165 DDR_NB_LOOPS (ddr));
3166 fprintf (dump_file, " )\n");
3168 fprintf (dump_file, ")\n");
3174 /* Return the direction for a given distance.
3175 FIXME: Computing dir this way is suboptimal, since dir can catch
3176 cases that dist is unable to represent. */
3178 static inline enum data_dependence_direction
3179 dir_from_dist (int dist)
3182 return dir_positive;
3184 return dir_negative;
3189 /* Compute the classic per loop direction vector. DDR is the data
3190 dependence relation to build a vector from. */
3193 build_classic_dir_vector (struct data_dependence_relation *ddr)
3196 lambda_vector dist_v;
3198 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v); i++)
3200 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3202 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3203 dir_v[j] = dir_from_dist (dist_v[j]);
3205 save_dir_v (ddr, dir_v);
3209 /* Helper function. Returns true when there is a dependence between
3210 data references DRA and DRB. */
3213 subscript_dependence_tester_1 (struct data_dependence_relation *ddr,
3214 struct data_reference *dra,
3215 struct data_reference *drb,
3216 struct loop *loop_nest)
3219 tree last_conflicts;
3220 struct subscript *subscript;
3222 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3225 conflict_function *overlaps_a, *overlaps_b;
3227 analyze_overlapping_iterations (DR_ACCESS_FN (dra, i),
3228 DR_ACCESS_FN (drb, i),
3229 &overlaps_a, &overlaps_b,
3230 &last_conflicts, loop_nest);
3232 if (CF_NOT_KNOWN_P (overlaps_a)
3233 || CF_NOT_KNOWN_P (overlaps_b))
3235 finalize_ddr_dependent (ddr, chrec_dont_know);
3236 dependence_stats.num_dependence_undetermined++;
3237 free_conflict_function (overlaps_a);
3238 free_conflict_function (overlaps_b);
3242 else if (CF_NO_DEPENDENCE_P (overlaps_a)
3243 || CF_NO_DEPENDENCE_P (overlaps_b))
3245 finalize_ddr_dependent (ddr, chrec_known);
3246 dependence_stats.num_dependence_independent++;
3247 free_conflict_function (overlaps_a);
3248 free_conflict_function (overlaps_b);
3254 if (SUB_CONFLICTS_IN_A (subscript))
3255 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3256 if (SUB_CONFLICTS_IN_B (subscript))
3257 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3259 SUB_CONFLICTS_IN_A (subscript) = overlaps_a;
3260 SUB_CONFLICTS_IN_B (subscript) = overlaps_b;
3261 SUB_LAST_CONFLICT (subscript) = last_conflicts;
3268 /* Computes the conflicting iterations in LOOP_NEST, and initialize DDR. */
3271 subscript_dependence_tester (struct data_dependence_relation *ddr,
3272 struct loop *loop_nest)
3275 if (dump_file && (dump_flags & TDF_DETAILS))
3276 fprintf (dump_file, "(subscript_dependence_tester \n");
3278 if (subscript_dependence_tester_1 (ddr, DDR_A (ddr), DDR_B (ddr), loop_nest))
3279 dependence_stats.num_dependence_dependent++;
3281 compute_subscript_distance (ddr);
3282 if (build_classic_dist_vector (ddr, loop_nest))
3283 build_classic_dir_vector (ddr);
3285 if (dump_file && (dump_flags & TDF_DETAILS))
3286 fprintf (dump_file, ")\n");
3289 /* Returns true when all the access functions of A are affine or
3290 constant with respect to LOOP_NEST. */
3293 access_functions_are_affine_or_constant_p (const struct data_reference *a,
3294 const struct loop *loop_nest)
3297 VEC(tree,heap) *fns = DR_ACCESS_FNS (a);
3300 for (i = 0; VEC_iterate (tree, fns, i, t); i++)
3301 if (!evolution_function_is_invariant_p (t, loop_nest->num)
3302 && !evolution_function_is_affine_multivariate_p (t, loop_nest->num))
3308 /* Return true if we can create an affine data-ref for OP in STMT. */
3311 stmt_simple_memref_p (struct loop *loop, gimple stmt, tree op)
3313 data_reference_p dr;
3316 dr = create_data_ref (loop, op, stmt, true);
3317 if (!access_functions_are_affine_or_constant_p (dr, loop))
3324 /* Initializes an equation for an OMEGA problem using the information
3325 contained in the ACCESS_FUN. Returns true when the operation
3328 PB is the omega constraint system.
3329 EQ is the number of the equation to be initialized.
3330 OFFSET is used for shifting the variables names in the constraints:
3331 a constrain is composed of 2 * the number of variables surrounding
3332 dependence accesses. OFFSET is set either to 0 for the first n variables,
3333 then it is set to n.
3334 ACCESS_FUN is expected to be an affine chrec. */
3337 init_omega_eq_with_af (omega_pb pb, unsigned eq,
3338 unsigned int offset, tree access_fun,
3339 struct data_dependence_relation *ddr)
3341 switch (TREE_CODE (access_fun))
3343 case POLYNOMIAL_CHREC:
3345 tree left = CHREC_LEFT (access_fun);
3346 tree right = CHREC_RIGHT (access_fun);
3347 int var = CHREC_VARIABLE (access_fun);
3350 if (TREE_CODE (right) != INTEGER_CST)
3353 var_idx = index_in_loop_nest (var, DDR_LOOP_NEST (ddr));
3354 pb->eqs[eq].coef[offset + var_idx + 1] = int_cst_value (right);
3356 /* Compute the innermost loop index. */
3357 DDR_INNER_LOOP (ddr) = MAX (DDR_INNER_LOOP (ddr), var_idx);
3360 pb->eqs[eq].coef[var_idx + DDR_NB_LOOPS (ddr) + 1]
3361 += int_cst_value (right);
3363 switch (TREE_CODE (left))
3365 case POLYNOMIAL_CHREC:
3366 return init_omega_eq_with_af (pb, eq, offset, left, ddr);
3369 pb->eqs[eq].coef[0] += int_cst_value (left);
3378 pb->eqs[eq].coef[0] += int_cst_value (access_fun);
3386 /* As explained in the comments preceding init_omega_for_ddr, we have
3387 to set up a system for each loop level, setting outer loops
3388 variation to zero, and current loop variation to positive or zero.
3389 Save each lexico positive distance vector. */
3392 omega_extract_distance_vectors (omega_pb pb,
3393 struct data_dependence_relation *ddr)
3397 struct loop *loopi, *loopj;
3398 enum omega_result res;
3400 /* Set a new problem for each loop in the nest. The basis is the
3401 problem that we have initialized until now. On top of this we
3402 add new constraints. */
3403 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3404 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3407 omega_pb copy = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr),
3408 DDR_NB_LOOPS (ddr));
3410 omega_copy_problem (copy, pb);
3412 /* For all the outer loops "loop_j", add "dj = 0". */
3414 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3416 eq = omega_add_zero_eq (copy, omega_black);
3417 copy->eqs[eq].coef[j + 1] = 1;
3420 /* For "loop_i", add "0 <= di". */
3421 geq = omega_add_zero_geq (copy, omega_black);
3422 copy->geqs[geq].coef[i + 1] = 1;
3424 /* Reduce the constraint system, and test that the current
3425 problem is feasible. */
3426 res = omega_simplify_problem (copy);
3427 if (res == omega_false
3428 || res == omega_unknown
3429 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3432 for (eq = 0; eq < copy->num_subs; eq++)
3433 if (copy->subs[eq].key == (int) i + 1)
3435 dist = copy->subs[eq].coef[0];
3441 /* Reinitialize problem... */
3442 omega_copy_problem (copy, pb);
3444 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3446 eq = omega_add_zero_eq (copy, omega_black);
3447 copy->eqs[eq].coef[j + 1] = 1;
3450 /* ..., but this time "di = 1". */
3451 eq = omega_add_zero_eq (copy, omega_black);
3452 copy->eqs[eq].coef[i + 1] = 1;
3453 copy->eqs[eq].coef[0] = -1;
3455 res = omega_simplify_problem (copy);
3456 if (res == omega_false
3457 || res == omega_unknown
3458 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3461 for (eq = 0; eq < copy->num_subs; eq++)
3462 if (copy->subs[eq].key == (int) i + 1)
3464 dist = copy->subs[eq].coef[0];
3470 /* Save the lexicographically positive distance vector. */
3473 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3474 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3478 for (eq = 0; eq < copy->num_subs; eq++)
3479 if (copy->subs[eq].key > 0)
3481 dist = copy->subs[eq].coef[0];
3482 dist_v[copy->subs[eq].key - 1] = dist;
3485 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3486 dir_v[j] = dir_from_dist (dist_v[j]);
3488 save_dist_v (ddr, dist_v);
3489 save_dir_v (ddr, dir_v);
3493 omega_free_problem (copy);
3497 /* This is called for each subscript of a tuple of data references:
3498 insert an equality for representing the conflicts. */
3501 omega_setup_subscript (tree access_fun_a, tree access_fun_b,
3502 struct data_dependence_relation *ddr,
3503 omega_pb pb, bool *maybe_dependent)
3506 tree type = signed_type_for_types (TREE_TYPE (access_fun_a),
3507 TREE_TYPE (access_fun_b));
3508 tree fun_a = chrec_convert (type, access_fun_a, NULL);
3509 tree fun_b = chrec_convert (type, access_fun_b, NULL);
3510 tree difference = chrec_fold_minus (type, fun_a, fun_b);
3512 /* When the fun_a - fun_b is not constant, the dependence is not
3513 captured by the classic distance vector representation. */
3514 if (TREE_CODE (difference) != INTEGER_CST)
3518 if (ziv_subscript_p (fun_a, fun_b) && !integer_zerop (difference))
3520 /* There is no dependence. */
3521 *maybe_dependent = false;
3525 fun_b = chrec_fold_multiply (type, fun_b, integer_minus_one_node);
3527 eq = omega_add_zero_eq (pb, omega_black);
3528 if (!init_omega_eq_with_af (pb, eq, DDR_NB_LOOPS (ddr), fun_a, ddr)
3529 || !init_omega_eq_with_af (pb, eq, 0, fun_b, ddr))
3530 /* There is probably a dependence, but the system of
3531 constraints cannot be built: answer "don't know". */
3535 if (DDR_NB_LOOPS (ddr) != 0 && pb->eqs[eq].coef[0]
3536 && !int_divides_p (lambda_vector_gcd
3537 ((lambda_vector) &(pb->eqs[eq].coef[1]),
3538 2 * DDR_NB_LOOPS (ddr)),
3539 pb->eqs[eq].coef[0]))
3541 /* There is no dependence. */
3542 *maybe_dependent = false;
3549 /* Helper function, same as init_omega_for_ddr but specialized for
3550 data references A and B. */
3553 init_omega_for_ddr_1 (struct data_reference *dra, struct data_reference *drb,
3554 struct data_dependence_relation *ddr,
3555 omega_pb pb, bool *maybe_dependent)
3560 unsigned nb_loops = DDR_NB_LOOPS (ddr);
3562 /* Insert an equality per subscript. */
3563 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
3565 if (!omega_setup_subscript (DR_ACCESS_FN (dra, i), DR_ACCESS_FN (drb, i),
3566 ddr, pb, maybe_dependent))
3568 else if (*maybe_dependent == false)
3570 /* There is no dependence. */
3571 DDR_ARE_DEPENDENT (ddr) = chrec_known;
3576 /* Insert inequalities: constraints corresponding to the iteration
3577 domain, i.e. the loops surrounding the references "loop_x" and
3578 the distance variables "dx". The layout of the OMEGA
3579 representation is as follows:
3580 - coef[0] is the constant
3581 - coef[1..nb_loops] are the protected variables that will not be
3582 removed by the solver: the "dx"
3583 - coef[nb_loops + 1, 2*nb_loops] are the loop variables: "loop_x".
3585 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3586 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3588 HOST_WIDE_INT nbi = estimated_loop_iterations_int (loopi, false);
3591 ineq = omega_add_zero_geq (pb, omega_black);
3592 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3594 /* 0 <= loop_x + dx */
3595 ineq = omega_add_zero_geq (pb, omega_black);
3596 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3597 pb->geqs[ineq].coef[i + 1] = 1;
3601 /* loop_x <= nb_iters */
3602 ineq = omega_add_zero_geq (pb, omega_black);
3603 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3604 pb->geqs[ineq].coef[0] = nbi;
3606 /* loop_x + dx <= nb_iters */
3607 ineq = omega_add_zero_geq (pb, omega_black);
3608 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3609 pb->geqs[ineq].coef[i + 1] = -1;
3610 pb->geqs[ineq].coef[0] = nbi;
3612 /* A step "dx" bigger than nb_iters is not feasible, so
3613 add "0 <= nb_iters + dx", */
3614 ineq = omega_add_zero_geq (pb, omega_black);
3615 pb->geqs[ineq].coef[i + 1] = 1;
3616 pb->geqs[ineq].coef[0] = nbi;
3617 /* and "dx <= nb_iters". */
3618 ineq = omega_add_zero_geq (pb, omega_black);
3619 pb->geqs[ineq].coef[i + 1] = -1;
3620 pb->geqs[ineq].coef[0] = nbi;
3624 omega_extract_distance_vectors (pb, ddr);
3629 /* Sets up the Omega dependence problem for the data dependence
3630 relation DDR. Returns false when the constraint system cannot be
3631 built, ie. when the test answers "don't know". Returns true
3632 otherwise, and when independence has been proved (using one of the
3633 trivial dependence test), set MAYBE_DEPENDENT to false, otherwise
3634 set MAYBE_DEPENDENT to true.
3636 Example: for setting up the dependence system corresponding to the
3637 conflicting accesses
3642 | ... A[2*j, 2*(i + j)]
3646 the following constraints come from the iteration domain:
3653 where di, dj are the distance variables. The constraints
3654 representing the conflicting elements are:
3657 i + 1 = 2 * (i + di + j + dj)
3659 For asking that the resulting distance vector (di, dj) be
3660 lexicographically positive, we insert the constraint "di >= 0". If
3661 "di = 0" in the solution, we fix that component to zero, and we
3662 look at the inner loops: we set a new problem where all the outer
3663 loop distances are zero, and fix this inner component to be
3664 positive. When one of the components is positive, we save that
3665 distance, and set a new problem where the distance on this loop is
3666 zero, searching for other distances in the inner loops. Here is
3667 the classic example that illustrates that we have to set for each
3668 inner loop a new problem:
3676 we have to save two distances (1, 0) and (0, 1).
3678 Given two array references, refA and refB, we have to set the
3679 dependence problem twice, refA vs. refB and refB vs. refA, and we
3680 cannot do a single test, as refB might occur before refA in the
3681 inner loops, and the contrary when considering outer loops: ex.
3686 | T[{1,+,1}_2][{1,+,1}_1] // refA
3687 | T[{2,+,1}_2][{0,+,1}_1] // refB
3692 refB touches the elements in T before refA, and thus for the same
3693 loop_0 refB precedes refA: ie. the distance vector (0, 1, -1)
3694 but for successive loop_0 iterations, we have (1, -1, 1)
3696 The Omega solver expects the distance variables ("di" in the
3697 previous example) to come first in the constraint system (as
3698 variables to be protected, or "safe" variables), the constraint
3699 system is built using the following layout:
3701 "cst | distance vars | index vars".
3705 init_omega_for_ddr (struct data_dependence_relation *ddr,
3706 bool *maybe_dependent)
3711 *maybe_dependent = true;
3713 if (same_access_functions (ddr))
3716 lambda_vector dir_v;
3718 /* Save the 0 vector. */
3719 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3720 dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3721 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3722 dir_v[j] = dir_equal;
3723 save_dir_v (ddr, dir_v);
3725 /* Save the dependences carried by outer loops. */
3726 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3727 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3729 omega_free_problem (pb);
3733 /* Omega expects the protected variables (those that have to be kept
3734 after elimination) to appear first in the constraint system.
3735 These variables are the distance variables. In the following
3736 initialization we declare NB_LOOPS safe variables, and the total
3737 number of variables for the constraint system is 2*NB_LOOPS. */
3738 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3739 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3741 omega_free_problem (pb);
3743 /* Stop computation if not decidable, or no dependence. */
3744 if (res == false || *maybe_dependent == false)
3747 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3748 res = init_omega_for_ddr_1 (DDR_B (ddr), DDR_A (ddr), ddr, pb,
3750 omega_free_problem (pb);
3755 /* Return true when DDR contains the same information as that stored
3756 in DIR_VECTS and in DIST_VECTS, return false otherwise. */
3759 ddr_consistent_p (FILE *file,
3760 struct data_dependence_relation *ddr,
3761 VEC (lambda_vector, heap) *dist_vects,
3762 VEC (lambda_vector, heap) *dir_vects)
3766 /* If dump_file is set, output there. */
3767 if (dump_file && (dump_flags & TDF_DETAILS))
3770 if (VEC_length (lambda_vector, dist_vects) != DDR_NUM_DIST_VECTS (ddr))
3772 lambda_vector b_dist_v;
3773 fprintf (file, "\n(Number of distance vectors differ: Banerjee has %d, Omega has %d.\n",
3774 VEC_length (lambda_vector, dist_vects),
3775 DDR_NUM_DIST_VECTS (ddr));
3777 fprintf (file, "Banerjee dist vectors:\n");
3778 for (i = 0; VEC_iterate (lambda_vector, dist_vects, i, b_dist_v); i++)
3779 print_lambda_vector (file, b_dist_v, DDR_NB_LOOPS (ddr));
3781 fprintf (file, "Omega dist vectors:\n");
3782 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3783 print_lambda_vector (file, DDR_DIST_VECT (ddr, i), DDR_NB_LOOPS (ddr));
3785 fprintf (file, "data dependence relation:\n");
3786 dump_data_dependence_relation (file, ddr);
3788 fprintf (file, ")\n");
3792 if (VEC_length (lambda_vector, dir_vects) != DDR_NUM_DIR_VECTS (ddr))
3794 fprintf (file, "\n(Number of direction vectors differ: Banerjee has %d, Omega has %d.)\n",
3795 VEC_length (lambda_vector, dir_vects),
3796 DDR_NUM_DIR_VECTS (ddr));
3800 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3802 lambda_vector a_dist_v;
3803 lambda_vector b_dist_v = DDR_DIST_VECT (ddr, i);
3805 /* Distance vectors are not ordered in the same way in the DDR
3806 and in the DIST_VECTS: search for a matching vector. */
3807 for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, a_dist_v); j++)
3808 if (lambda_vector_equal (a_dist_v, b_dist_v, DDR_NB_LOOPS (ddr)))
3811 if (j == VEC_length (lambda_vector, dist_vects))
3813 fprintf (file, "\n(Dist vectors from the first dependence analyzer:\n");
3814 print_dist_vectors (file, dist_vects, DDR_NB_LOOPS (ddr));
3815 fprintf (file, "not found in Omega dist vectors:\n");
3816 print_dist_vectors (file, DDR_DIST_VECTS (ddr), DDR_NB_LOOPS (ddr));
3817 fprintf (file, "data dependence relation:\n");
3818 dump_data_dependence_relation (file, ddr);
3819 fprintf (file, ")\n");
3823 for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++)
3825 lambda_vector a_dir_v;
3826 lambda_vector b_dir_v = DDR_DIR_VECT (ddr, i);
3828 /* Direction vectors are not ordered in the same way in the DDR
3829 and in the DIR_VECTS: search for a matching vector. */
3830 for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, a_dir_v); j++)
3831 if (lambda_vector_equal (a_dir_v, b_dir_v, DDR_NB_LOOPS (ddr)))
3834 if (j == VEC_length (lambda_vector, dist_vects))
3836 fprintf (file, "\n(Dir vectors from the first dependence analyzer:\n");
3837 print_dir_vectors (file, dir_vects, DDR_NB_LOOPS (ddr));
3838 fprintf (file, "not found in Omega dir vectors:\n");
3839 print_dir_vectors (file, DDR_DIR_VECTS (ddr), DDR_NB_LOOPS (ddr));
3840 fprintf (file, "data dependence relation:\n");
3841 dump_data_dependence_relation (file, ddr);
3842 fprintf (file, ")\n");
3849 /* This computes the affine dependence relation between A and B with
3850 respect to LOOP_NEST. CHREC_KNOWN is used for representing the
3851 independence between two accesses, while CHREC_DONT_KNOW is used
3852 for representing the unknown relation.
3854 Note that it is possible to stop the computation of the dependence
3855 relation the first time we detect a CHREC_KNOWN element for a given
3859 compute_affine_dependence (struct data_dependence_relation *ddr,
3860 struct loop *loop_nest)
3862 struct data_reference *dra = DDR_A (ddr);
3863 struct data_reference *drb = DDR_B (ddr);
3865 if (dump_file && (dump_flags & TDF_DETAILS))
3867 fprintf (dump_file, "(compute_affine_dependence\n");
3868 fprintf (dump_file, " (stmt_a = \n");
3869 print_gimple_stmt (dump_file, DR_STMT (dra), 0, 0);
3870 fprintf (dump_file, ")\n (stmt_b = \n");
3871 print_gimple_stmt (dump_file, DR_STMT (drb), 0, 0);
3872 fprintf (dump_file, ")\n");
3875 /* Analyze only when the dependence relation is not yet known. */
3876 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE
3877 && !DDR_SELF_REFERENCE (ddr))
3879 dependence_stats.num_dependence_tests++;
3881 if (access_functions_are_affine_or_constant_p (dra, loop_nest)
3882 && access_functions_are_affine_or_constant_p (drb, loop_nest))
3884 if (flag_check_data_deps)
3886 /* Compute the dependences using the first algorithm. */
3887 subscript_dependence_tester (ddr, loop_nest);
3889 if (dump_file && (dump_flags & TDF_DETAILS))
3891 fprintf (dump_file, "\n\nBanerjee Analyzer\n");
3892 dump_data_dependence_relation (dump_file, ddr);
3895 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
3897 bool maybe_dependent;
3898 VEC (lambda_vector, heap) *dir_vects, *dist_vects;
3900 /* Save the result of the first DD analyzer. */
3901 dist_vects = DDR_DIST_VECTS (ddr);
3902 dir_vects = DDR_DIR_VECTS (ddr);
3904 /* Reset the information. */
3905 DDR_DIST_VECTS (ddr) = NULL;
3906 DDR_DIR_VECTS (ddr) = NULL;
3908 /* Compute the same information using Omega. */
3909 if (!init_omega_for_ddr (ddr, &maybe_dependent))
3910 goto csys_dont_know;
3912 if (dump_file && (dump_flags & TDF_DETAILS))
3914 fprintf (dump_file, "Omega Analyzer\n");
3915 dump_data_dependence_relation (dump_file, ddr);
3918 /* Check that we get the same information. */
3919 if (maybe_dependent)
3920 gcc_assert (ddr_consistent_p (stderr, ddr, dist_vects,
3925 subscript_dependence_tester (ddr, loop_nest);
3928 /* As a last case, if the dependence cannot be determined, or if
3929 the dependence is considered too difficult to determine, answer
3934 dependence_stats.num_dependence_undetermined++;
3936 if (dump_file && (dump_flags & TDF_DETAILS))
3938 fprintf (dump_file, "Data ref a:\n");
3939 dump_data_reference (dump_file, dra);
3940 fprintf (dump_file, "Data ref b:\n");
3941 dump_data_reference (dump_file, drb);
3942 fprintf (dump_file, "affine dependence test not usable: access function not affine or constant.\n");
3944 finalize_ddr_dependent (ddr, chrec_dont_know);
3948 if (dump_file && (dump_flags & TDF_DETAILS))
3949 fprintf (dump_file, ")\n");
3952 /* This computes the dependence relation for the same data
3953 reference into DDR. */
3956 compute_self_dependence (struct data_dependence_relation *ddr)
3959 struct subscript *subscript;
3961 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3964 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3967 if (SUB_CONFLICTS_IN_A (subscript))
3968 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3969 if (SUB_CONFLICTS_IN_B (subscript))
3970 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3972 /* The accessed index overlaps for each iteration. */
3973 SUB_CONFLICTS_IN_A (subscript)
3974 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3975 SUB_CONFLICTS_IN_B (subscript)
3976 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3977 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
3980 /* The distance vector is the zero vector. */
3981 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3982 save_dir_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3985 /* Compute in DEPENDENCE_RELATIONS the data dependence graph for all
3986 the data references in DATAREFS, in the LOOP_NEST. When
3987 COMPUTE_SELF_AND_RR is FALSE, don't compute read-read and self
3991 compute_all_dependences (VEC (data_reference_p, heap) *datarefs,
3992 VEC (ddr_p, heap) **dependence_relations,
3993 VEC (loop_p, heap) *loop_nest,
3994 bool compute_self_and_rr)
3996 struct data_dependence_relation *ddr;
3997 struct data_reference *a, *b;
4000 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4001 for (j = i + 1; VEC_iterate (data_reference_p, datarefs, j, b); j++)
4002 if (!DR_IS_READ (a) || !DR_IS_READ (b) || compute_self_and_rr)
4004 ddr = initialize_data_dependence_relation (a, b, loop_nest);
4005 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4006 compute_affine_dependence (ddr, VEC_index (loop_p, loop_nest, 0));
4009 if (compute_self_and_rr)
4010 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4012 ddr = initialize_data_dependence_relation (a, a, loop_nest);
4013 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4014 compute_self_dependence (ddr);
4018 /* Stores the locations of memory references in STMT to REFERENCES. Returns
4019 true if STMT clobbers memory, false otherwise. */
4022 get_references_in_stmt (gimple stmt, VEC (data_ref_loc, heap) **references)
4024 bool clobbers_memory = false;
4027 enum gimple_code stmt_code = gimple_code (stmt);
4031 /* ASM_EXPR and CALL_EXPR may embed arbitrary side effects.
4032 Calls have side-effects, except those to const or pure
4034 if ((stmt_code == GIMPLE_CALL
4035 && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
4036 || (stmt_code == GIMPLE_ASM
4037 && gimple_asm_volatile_p (stmt)))
4038 clobbers_memory = true;
4040 if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
4041 return clobbers_memory;
4043 if (stmt_code == GIMPLE_ASSIGN)
4046 op0 = gimple_assign_lhs_ptr (stmt);
4047 op1 = gimple_assign_rhs1_ptr (stmt);
4050 || (REFERENCE_CLASS_P (*op1)
4051 && (base = get_base_address (*op1))
4052 && TREE_CODE (base) != SSA_NAME))
4054 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4056 ref->is_read = true;
4060 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4062 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4064 ref->is_read = false;
4067 else if (stmt_code == GIMPLE_CALL)
4069 unsigned i, n = gimple_call_num_args (stmt);
4071 for (i = 0; i < n; i++)
4073 op0 = gimple_call_arg_ptr (stmt, i);
4076 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4078 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4080 ref->is_read = true;
4085 return clobbers_memory;
4088 /* Stores the data references in STMT to DATAREFS. If there is an unanalyzable
4089 reference, returns false, otherwise returns true. NEST is the outermost
4090 loop of the loop nest in which the references should be analyzed. */
4093 find_data_references_in_stmt (struct loop *nest, gimple stmt,
4094 VEC (data_reference_p, heap) **datarefs)
4097 VEC (data_ref_loc, heap) *references;
4100 data_reference_p dr;
4102 if (get_references_in_stmt (stmt, &references))
4104 VEC_free (data_ref_loc, heap, references);
4108 for (i = 0; VEC_iterate (data_ref_loc, references, i, ref); i++)
4110 dr = create_data_ref (nest, *ref->pos, stmt, ref->is_read);
4111 gcc_assert (dr != NULL);
4113 /* FIXME -- data dependence analysis does not work correctly for objects with
4114 invariant addresses. Let us fail here until the problem is fixed. */
4115 if (dr_address_invariant_p (dr))
4118 if (dump_file && (dump_flags & TDF_DETAILS))
4119 fprintf (dump_file, "\tFAILED as dr address is invariant\n");
4124 VEC_safe_push (data_reference_p, heap, *datarefs, dr);
4126 VEC_free (data_ref_loc, heap, references);
4130 /* Search the data references in LOOP, and record the information into
4131 DATAREFS. Returns chrec_dont_know when failing to analyze a
4132 difficult case, returns NULL_TREE otherwise.
4134 TODO: This function should be made smarter so that it can handle address
4135 arithmetic as if they were array accesses, etc. */
4138 find_data_references_in_loop (struct loop *loop,
4139 VEC (data_reference_p, heap) **datarefs)
4141 basic_block bb, *bbs;
4143 gimple_stmt_iterator bsi;
4145 bbs = get_loop_body_in_dom_order (loop);
4147 for (i = 0; i < loop->num_nodes; i++)
4151 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4153 gimple stmt = gsi_stmt (bsi);
4155 if (!find_data_references_in_stmt (loop, stmt, datarefs))
4157 struct data_reference *res;
4158 res = XCNEW (struct data_reference);
4159 VEC_safe_push (data_reference_p, heap, *datarefs, res);
4162 return chrec_dont_know;
4171 /* Recursive helper function. */
4174 find_loop_nest_1 (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4176 /* Inner loops of the nest should not contain siblings. Example:
4177 when there are two consecutive loops,
4188 the dependence relation cannot be captured by the distance
4193 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4195 return find_loop_nest_1 (loop->inner, loop_nest);
4199 /* Return false when the LOOP is not well nested. Otherwise return
4200 true and insert in LOOP_NEST the loops of the nest. LOOP_NEST will
4201 contain the loops from the outermost to the innermost, as they will
4202 appear in the classic distance vector. */
4205 find_loop_nest (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4207 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4209 return find_loop_nest_1 (loop->inner, loop_nest);
4213 /* Returns true when the data dependences have been computed, false otherwise.
4214 Given a loop nest LOOP, the following vectors are returned:
4215 DATAREFS is initialized to all the array elements contained in this loop,
4216 DEPENDENCE_RELATIONS contains the relations between the data references.
4217 Compute read-read and self relations if
4218 COMPUTE_SELF_AND_READ_READ_DEPENDENCES is TRUE. */
4221 compute_data_dependences_for_loop (struct loop *loop,
4222 bool compute_self_and_read_read_dependences,
4223 VEC (data_reference_p, heap) **datarefs,
4224 VEC (ddr_p, heap) **dependence_relations)
4227 VEC (loop_p, heap) *vloops = VEC_alloc (loop_p, heap, 3);
4229 memset (&dependence_stats, 0, sizeof (dependence_stats));
4231 /* If the loop nest is not well formed, or one of the data references
4232 is not computable, give up without spending time to compute other
4235 || !find_loop_nest (loop, &vloops)
4236 || find_data_references_in_loop (loop, datarefs) == chrec_dont_know)
4238 struct data_dependence_relation *ddr;
4240 /* Insert a single relation into dependence_relations:
4242 ddr = initialize_data_dependence_relation (NULL, NULL, vloops);
4243 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4247 compute_all_dependences (*datarefs, dependence_relations, vloops,
4248 compute_self_and_read_read_dependences);
4250 if (dump_file && (dump_flags & TDF_STATS))
4252 fprintf (dump_file, "Dependence tester statistics:\n");
4254 fprintf (dump_file, "Number of dependence tests: %d\n",
4255 dependence_stats.num_dependence_tests);
4256 fprintf (dump_file, "Number of dependence tests classified dependent: %d\n",
4257 dependence_stats.num_dependence_dependent);
4258 fprintf (dump_file, "Number of dependence tests classified independent: %d\n",
4259 dependence_stats.num_dependence_independent);
4260 fprintf (dump_file, "Number of undetermined dependence tests: %d\n",
4261 dependence_stats.num_dependence_undetermined);
4263 fprintf (dump_file, "Number of subscript tests: %d\n",
4264 dependence_stats.num_subscript_tests);
4265 fprintf (dump_file, "Number of undetermined subscript tests: %d\n",
4266 dependence_stats.num_subscript_undetermined);
4267 fprintf (dump_file, "Number of same subscript function: %d\n",
4268 dependence_stats.num_same_subscript_function);
4270 fprintf (dump_file, "Number of ziv tests: %d\n",
4271 dependence_stats.num_ziv);
4272 fprintf (dump_file, "Number of ziv tests returning dependent: %d\n",
4273 dependence_stats.num_ziv_dependent);
4274 fprintf (dump_file, "Number of ziv tests returning independent: %d\n",
4275 dependence_stats.num_ziv_independent);
4276 fprintf (dump_file, "Number of ziv tests unimplemented: %d\n",
4277 dependence_stats.num_ziv_unimplemented);
4279 fprintf (dump_file, "Number of siv tests: %d\n",
4280 dependence_stats.num_siv);
4281 fprintf (dump_file, "Number of siv tests returning dependent: %d\n",
4282 dependence_stats.num_siv_dependent);
4283 fprintf (dump_file, "Number of siv tests returning independent: %d\n",
4284 dependence_stats.num_siv_independent);
4285 fprintf (dump_file, "Number of siv tests unimplemented: %d\n",
4286 dependence_stats.num_siv_unimplemented);
4288 fprintf (dump_file, "Number of miv tests: %d\n",
4289 dependence_stats.num_miv);
4290 fprintf (dump_file, "Number of miv tests returning dependent: %d\n",
4291 dependence_stats.num_miv_dependent);
4292 fprintf (dump_file, "Number of miv tests returning independent: %d\n",
4293 dependence_stats.num_miv_independent);
4294 fprintf (dump_file, "Number of miv tests unimplemented: %d\n",
4295 dependence_stats.num_miv_unimplemented);
4301 /* Entry point (for testing only). Analyze all the data references
4302 and the dependence relations in LOOP.
4304 The data references are computed first.
4306 A relation on these nodes is represented by a complete graph. Some
4307 of the relations could be of no interest, thus the relations can be
4310 In the following function we compute all the relations. This is
4311 just a first implementation that is here for:
4312 - for showing how to ask for the dependence relations,
4313 - for the debugging the whole dependence graph,
4314 - for the dejagnu testcases and maintenance.
4316 It is possible to ask only for a part of the graph, avoiding to
4317 compute the whole dependence graph. The computed dependences are
4318 stored in a knowledge base (KB) such that later queries don't
4319 recompute the same information. The implementation of this KB is
4320 transparent to the optimizer, and thus the KB can be changed with a
4321 more efficient implementation, or the KB could be disabled. */
4323 analyze_all_data_dependences (struct loop *loop)
4326 int nb_data_refs = 10;
4327 VEC (data_reference_p, heap) *datarefs =
4328 VEC_alloc (data_reference_p, heap, nb_data_refs);
4329 VEC (ddr_p, heap) *dependence_relations =
4330 VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs);
4332 /* Compute DDs on the whole function. */
4333 compute_data_dependences_for_loop (loop, false, &datarefs,
4334 &dependence_relations);
4338 dump_data_dependence_relations (dump_file, dependence_relations);
4339 fprintf (dump_file, "\n\n");
4341 if (dump_flags & TDF_DETAILS)
4342 dump_dist_dir_vectors (dump_file, dependence_relations);
4344 if (dump_flags & TDF_STATS)
4346 unsigned nb_top_relations = 0;
4347 unsigned nb_bot_relations = 0;
4348 unsigned nb_basename_differ = 0;
4349 unsigned nb_chrec_relations = 0;
4350 struct data_dependence_relation *ddr;
4352 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4354 if (chrec_contains_undetermined (DDR_ARE_DEPENDENT (ddr)))
4357 else if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
4359 struct data_reference *a = DDR_A (ddr);
4360 struct data_reference *b = DDR_B (ddr);
4362 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
4363 nb_basename_differ++;
4369 nb_chrec_relations++;
4372 gather_stats_on_scev_database ();
4376 free_dependence_relations (dependence_relations);
4377 free_data_refs (datarefs);
4380 /* Computes all the data dependences and check that the results of
4381 several analyzers are the same. */
4384 tree_check_data_deps (void)
4387 struct loop *loop_nest;
4389 FOR_EACH_LOOP (li, loop_nest, 0)
4390 analyze_all_data_dependences (loop_nest);
4393 /* Free the memory used by a data dependence relation DDR. */
4396 free_dependence_relation (struct data_dependence_relation *ddr)
4401 if (DDR_SUBSCRIPTS (ddr))
4402 free_subscripts (DDR_SUBSCRIPTS (ddr));
4403 if (DDR_DIST_VECTS (ddr))
4404 VEC_free (lambda_vector, heap, DDR_DIST_VECTS (ddr));
4405 if (DDR_DIR_VECTS (ddr))
4406 VEC_free (lambda_vector, heap, DDR_DIR_VECTS (ddr));
4411 /* Free the memory used by the data dependence relations from
4412 DEPENDENCE_RELATIONS. */
4415 free_dependence_relations (VEC (ddr_p, heap) *dependence_relations)
4418 struct data_dependence_relation *ddr;
4419 VEC (loop_p, heap) *loop_nest = NULL;
4421 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4425 if (loop_nest == NULL)
4426 loop_nest = DDR_LOOP_NEST (ddr);
4428 gcc_assert (DDR_LOOP_NEST (ddr) == NULL
4429 || DDR_LOOP_NEST (ddr) == loop_nest);
4430 free_dependence_relation (ddr);
4434 VEC_free (loop_p, heap, loop_nest);
4435 VEC_free (ddr_p, heap, dependence_relations);
4438 /* Free the memory used by the data references from DATAREFS. */
4441 free_data_refs (VEC (data_reference_p, heap) *datarefs)
4444 struct data_reference *dr;
4446 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
4448 VEC_free (data_reference_p, heap, datarefs);
4453 /* Dump vertex I in RDG to FILE. */
4456 dump_rdg_vertex (FILE *file, struct graph *rdg, int i)
4458 struct vertex *v = &(rdg->vertices[i]);
4459 struct graph_edge *e;
4461 fprintf (file, "(vertex %d: (%s%s) (in:", i,
4462 RDG_MEM_WRITE_STMT (rdg, i) ? "w" : "",
4463 RDG_MEM_READS_STMT (rdg, i) ? "r" : "");
4466 for (e = v->pred; e; e = e->pred_next)
4467 fprintf (file, " %d", e->src);
4469 fprintf (file, ") (out:");
4472 for (e = v->succ; e; e = e->succ_next)
4473 fprintf (file, " %d", e->dest);
4475 fprintf (file, ") \n");
4476 print_gimple_stmt (file, RDGV_STMT (v), 0, TDF_VOPS|TDF_MEMSYMS);
4477 fprintf (file, ")\n");
4480 /* Call dump_rdg_vertex on stderr. */
4483 debug_rdg_vertex (struct graph *rdg, int i)
4485 dump_rdg_vertex (stderr, rdg, i);
4488 /* Dump component C of RDG to FILE. If DUMPED is non-null, set the
4489 dumped vertices to that bitmap. */
4491 void dump_rdg_component (FILE *file, struct graph *rdg, int c, bitmap dumped)
4495 fprintf (file, "(%d\n", c);
4497 for (i = 0; i < rdg->n_vertices; i++)
4498 if (rdg->vertices[i].component == c)
4501 bitmap_set_bit (dumped, i);
4503 dump_rdg_vertex (file, rdg, i);
4506 fprintf (file, ")\n");
4509 /* Call dump_rdg_vertex on stderr. */
4512 debug_rdg_component (struct graph *rdg, int c)
4514 dump_rdg_component (stderr, rdg, c, NULL);
4517 /* Dump the reduced dependence graph RDG to FILE. */
4520 dump_rdg (FILE *file, struct graph *rdg)
4523 bitmap dumped = BITMAP_ALLOC (NULL);
4525 fprintf (file, "(rdg\n");
4527 for (i = 0; i < rdg->n_vertices; i++)
4528 if (!bitmap_bit_p (dumped, i))
4529 dump_rdg_component (file, rdg, rdg->vertices[i].component, dumped);
4531 fprintf (file, ")\n");
4532 BITMAP_FREE (dumped);
4535 /* Call dump_rdg on stderr. */
4538 debug_rdg (struct graph *rdg)
4540 dump_rdg (stderr, rdg);
4544 dot_rdg_1 (FILE *file, struct graph *rdg)
4548 fprintf (file, "digraph RDG {\n");
4550 for (i = 0; i < rdg->n_vertices; i++)
4552 struct vertex *v = &(rdg->vertices[i]);
4553 struct graph_edge *e;
4555 /* Highlight reads from memory. */
4556 if (RDG_MEM_READS_STMT (rdg, i))
4557 fprintf (file, "%d [style=filled, fillcolor=green]\n", i);
4559 /* Highlight stores to memory. */
4560 if (RDG_MEM_WRITE_STMT (rdg, i))
4561 fprintf (file, "%d [style=filled, fillcolor=red]\n", i);
4564 for (e = v->succ; e; e = e->succ_next)
4565 switch (RDGE_TYPE (e))
4568 fprintf (file, "%d -> %d [label=input] \n", i, e->dest);
4572 fprintf (file, "%d -> %d [label=output] \n", i, e->dest);
4576 /* These are the most common dependences: don't print these. */
4577 fprintf (file, "%d -> %d \n", i, e->dest);
4581 fprintf (file, "%d -> %d [label=anti] \n", i, e->dest);
4589 fprintf (file, "}\n\n");
4592 /* Display SCOP using dotty. */
4595 dot_rdg (struct graph *rdg)
4597 FILE *file = fopen ("/tmp/rdg.dot", "w");
4598 gcc_assert (file != NULL);
4600 dot_rdg_1 (file, rdg);
4603 system ("dotty /tmp/rdg.dot");
4607 /* This structure is used for recording the mapping statement index in
4610 struct rdg_vertex_info GTY(())
4616 /* Returns the index of STMT in RDG. */
4619 rdg_vertex_for_stmt (struct graph *rdg, gimple stmt)
4621 struct rdg_vertex_info rvi, *slot;
4624 slot = (struct rdg_vertex_info *) htab_find (rdg->indices, &rvi);
4632 /* Creates an edge in RDG for each distance vector from DDR. The
4633 order that we keep track of in the RDG is the order in which
4634 statements have to be executed. */
4637 create_rdg_edge_for_ddr (struct graph *rdg, ddr_p ddr)
4639 struct graph_edge *e;
4641 data_reference_p dra = DDR_A (ddr);
4642 data_reference_p drb = DDR_B (ddr);
4643 unsigned level = ddr_dependence_level (ddr);
4645 /* For non scalar dependences, when the dependence is REVERSED,
4646 statement B has to be executed before statement A. */
4648 && !DDR_REVERSED_P (ddr))
4650 data_reference_p tmp = dra;
4655 va = rdg_vertex_for_stmt (rdg, DR_STMT (dra));
4656 vb = rdg_vertex_for_stmt (rdg, DR_STMT (drb));
4658 if (va < 0 || vb < 0)
4661 e = add_edge (rdg, va, vb);
4662 e->data = XNEW (struct rdg_edge);
4664 RDGE_LEVEL (e) = level;
4665 RDGE_RELATION (e) = ddr;
4667 /* Determines the type of the data dependence. */
4668 if (DR_IS_READ (dra) && DR_IS_READ (drb))
4669 RDGE_TYPE (e) = input_dd;
4670 else if (!DR_IS_READ (dra) && !DR_IS_READ (drb))
4671 RDGE_TYPE (e) = output_dd;
4672 else if (!DR_IS_READ (dra) && DR_IS_READ (drb))
4673 RDGE_TYPE (e) = flow_dd;
4674 else if (DR_IS_READ (dra) && !DR_IS_READ (drb))
4675 RDGE_TYPE (e) = anti_dd;
4678 /* Creates dependence edges in RDG for all the uses of DEF. IDEF is
4679 the index of DEF in RDG. */
4682 create_rdg_edges_for_scalar (struct graph *rdg, tree def, int idef)
4684 use_operand_p imm_use_p;
4685 imm_use_iterator iterator;
4687 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, def)
4689 struct graph_edge *e;
4690 int use = rdg_vertex_for_stmt (rdg, USE_STMT (imm_use_p));
4695 e = add_edge (rdg, idef, use);
4696 e->data = XNEW (struct rdg_edge);
4697 RDGE_TYPE (e) = flow_dd;
4698 RDGE_RELATION (e) = NULL;
4702 /* Creates the edges of the reduced dependence graph RDG. */
4705 create_rdg_edges (struct graph *rdg, VEC (ddr_p, heap) *ddrs)
4708 struct data_dependence_relation *ddr;
4709 def_operand_p def_p;
4712 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
4713 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
4714 create_rdg_edge_for_ddr (rdg, ddr);
4716 for (i = 0; i < rdg->n_vertices; i++)
4717 FOR_EACH_PHI_OR_STMT_DEF (def_p, RDG_STMT (rdg, i),
4719 create_rdg_edges_for_scalar (rdg, DEF_FROM_PTR (def_p), i);
4722 /* Build the vertices of the reduced dependence graph RDG. */
4725 create_rdg_vertices (struct graph *rdg, VEC (gimple, heap) *stmts)
4730 for (i = 0; VEC_iterate (gimple, stmts, i, stmt); i++)
4732 VEC (data_ref_loc, heap) *references;
4734 struct vertex *v = &(rdg->vertices[i]);
4735 struct rdg_vertex_info *rvi = XNEW (struct rdg_vertex_info);
4736 struct rdg_vertex_info **slot;
4740 slot = (struct rdg_vertex_info **) htab_find_slot (rdg->indices, rvi, INSERT);
4747 v->data = XNEW (struct rdg_vertex);
4748 RDG_STMT (rdg, i) = stmt;
4750 RDG_MEM_WRITE_STMT (rdg, i) = false;
4751 RDG_MEM_READS_STMT (rdg, i) = false;
4752 if (gimple_code (stmt) == GIMPLE_PHI)
4755 get_references_in_stmt (stmt, &references);
4756 for (j = 0; VEC_iterate (data_ref_loc, references, j, ref); j++)
4758 RDG_MEM_WRITE_STMT (rdg, i) = true;
4760 RDG_MEM_READS_STMT (rdg, i) = true;
4762 VEC_free (data_ref_loc, heap, references);
4766 /* Initialize STMTS with all the statements of LOOP. When
4767 INCLUDE_PHIS is true, include also the PHI nodes. The order in
4768 which we discover statements is important as
4769 generate_loops_for_partition is using the same traversal for
4770 identifying statements. */
4773 stmts_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4776 basic_block *bbs = get_loop_body_in_dom_order (loop);
4778 for (i = 0; i < loop->num_nodes; i++)
4780 basic_block bb = bbs[i];
4781 gimple_stmt_iterator bsi;
4784 for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4785 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4787 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4789 stmt = gsi_stmt (bsi);
4790 if (gimple_code (stmt) != GIMPLE_LABEL)
4791 VEC_safe_push (gimple, heap, *stmts, stmt);
4798 /* Returns true when all the dependences are computable. */
4801 known_dependences_p (VEC (ddr_p, heap) *dependence_relations)
4806 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4807 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
4813 /* Computes a hash function for element ELT. */
4816 hash_stmt_vertex_info (const void *elt)
4818 const struct rdg_vertex_info *const rvi =
4819 (const struct rdg_vertex_info *) elt;
4820 gimple stmt = rvi->stmt;
4822 return htab_hash_pointer (stmt);
4825 /* Compares database elements E1 and E2. */
4828 eq_stmt_vertex_info (const void *e1, const void *e2)
4830 const struct rdg_vertex_info *elt1 = (const struct rdg_vertex_info *) e1;
4831 const struct rdg_vertex_info *elt2 = (const struct rdg_vertex_info *) e2;
4833 return elt1->stmt == elt2->stmt;
4836 /* Free the element E. */
4839 hash_stmt_vertex_del (void *e)
4844 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4845 statement of the loop nest, and one edge per data dependence or
4846 scalar dependence. */
4849 build_empty_rdg (int n_stmts)
4851 int nb_data_refs = 10;
4852 struct graph *rdg = new_graph (n_stmts);
4854 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4855 eq_stmt_vertex_info, hash_stmt_vertex_del);
4859 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4860 statement of the loop nest, and one edge per data dependence or
4861 scalar dependence. */
4864 build_rdg (struct loop *loop)
4866 int nb_data_refs = 10;
4867 struct graph *rdg = NULL;
4868 VEC (ddr_p, heap) *dependence_relations;
4869 VEC (data_reference_p, heap) *datarefs;
4870 VEC (gimple, heap) *stmts = VEC_alloc (gimple, heap, nb_data_refs);
4872 dependence_relations = VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs) ;
4873 datarefs = VEC_alloc (data_reference_p, heap, nb_data_refs);
4874 compute_data_dependences_for_loop (loop,
4877 &dependence_relations);
4879 if (!known_dependences_p (dependence_relations))
4881 free_dependence_relations (dependence_relations);
4882 free_data_refs (datarefs);
4883 VEC_free (gimple, heap, stmts);
4888 stmts_from_loop (loop, &stmts);
4889 rdg = build_empty_rdg (VEC_length (gimple, stmts));
4891 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4892 eq_stmt_vertex_info, hash_stmt_vertex_del);
4893 create_rdg_vertices (rdg, stmts);
4894 create_rdg_edges (rdg, dependence_relations);
4896 VEC_free (gimple, heap, stmts);
4900 /* Free the reduced dependence graph RDG. */
4903 free_rdg (struct graph *rdg)
4907 for (i = 0; i < rdg->n_vertices; i++)
4908 free (rdg->vertices[i].data);
4910 htab_delete (rdg->indices);
4914 /* Initialize STMTS with all the statements of LOOP that contain a
4918 stores_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4921 basic_block *bbs = get_loop_body_in_dom_order (loop);
4923 for (i = 0; i < loop->num_nodes; i++)
4925 basic_block bb = bbs[i];
4926 gimple_stmt_iterator bsi;
4928 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4929 if (!ZERO_SSA_OPERANDS (gsi_stmt (bsi), SSA_OP_VDEF))
4930 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4936 /* For a data reference REF, return the declaration of its base
4937 address or NULL_TREE if the base is not determined. */
4940 ref_base_address (gimple stmt, data_ref_loc *ref)
4942 tree base = NULL_TREE;
4944 struct data_reference *dr = XCNEW (struct data_reference);
4946 DR_STMT (dr) = stmt;
4947 DR_REF (dr) = *ref->pos;
4948 dr_analyze_innermost (dr);
4949 base_address = DR_BASE_ADDRESS (dr);
4954 switch (TREE_CODE (base_address))
4957 base = TREE_OPERAND (base_address, 0);
4961 base = base_address;
4970 /* Determines whether the statement from vertex V of the RDG has a
4971 definition used outside the loop that contains this statement. */
4974 rdg_defs_used_in_other_loops_p (struct graph *rdg, int v)
4976 gimple stmt = RDG_STMT (rdg, v);
4977 struct loop *loop = loop_containing_stmt (stmt);
4978 use_operand_p imm_use_p;
4979 imm_use_iterator iterator;
4981 def_operand_p def_p;
4986 FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, it, SSA_OP_DEF)
4988 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, DEF_FROM_PTR (def_p))
4990 if (loop_containing_stmt (USE_STMT (imm_use_p)) != loop)
4998 /* Determines whether statements S1 and S2 access to similar memory
4999 locations. Two memory accesses are considered similar when they
5000 have the same base address declaration, i.e. when their
5001 ref_base_address is the same. */
5004 have_similar_memory_accesses (gimple s1, gimple s2)
5008 VEC (data_ref_loc, heap) *refs1, *refs2;
5009 data_ref_loc *ref1, *ref2;
5011 get_references_in_stmt (s1, &refs1);
5012 get_references_in_stmt (s2, &refs2);
5014 for (i = 0; VEC_iterate (data_ref_loc, refs1, i, ref1); i++)
5016 tree base1 = ref_base_address (s1, ref1);
5019 for (j = 0; VEC_iterate (data_ref_loc, refs2, j, ref2); j++)
5020 if (base1 == ref_base_address (s2, ref2))
5028 VEC_free (data_ref_loc, heap, refs1);
5029 VEC_free (data_ref_loc, heap, refs2);
5033 /* Helper function for the hashtab. */
5036 have_similar_memory_accesses_1 (const void *s1, const void *s2)
5038 return have_similar_memory_accesses (CONST_CAST_GIMPLE ((const_gimple) s1),
5039 CONST_CAST_GIMPLE ((const_gimple) s2));
5042 /* Helper function for the hashtab. */
5045 ref_base_address_1 (const void *s)
5047 gimple stmt = CONST_CAST_GIMPLE ((const_gimple) s);
5049 VEC (data_ref_loc, heap) *refs;
5053 get_references_in_stmt (stmt, &refs);
5055 for (i = 0; VEC_iterate (data_ref_loc, refs, i, ref); i++)
5058 res = htab_hash_pointer (ref_base_address (stmt, ref));
5062 VEC_free (data_ref_loc, heap, refs);
5066 /* Try to remove duplicated write data references from STMTS. */
5069 remove_similar_memory_refs (VEC (gimple, heap) **stmts)
5073 htab_t seen = htab_create (VEC_length (gimple, *stmts), ref_base_address_1,
5074 have_similar_memory_accesses_1, NULL);
5076 for (i = 0; VEC_iterate (gimple, *stmts, i, stmt); )
5080 slot = htab_find_slot (seen, stmt, INSERT);
5083 VEC_ordered_remove (gimple, *stmts, i);
5086 *slot = (void *) stmt;
5094 /* Returns the index of PARAMETER in the parameters vector of the
5095 ACCESS_MATRIX. If PARAMETER does not exist return -1. */
5098 access_matrix_get_index_for_parameter (tree parameter,
5099 struct access_matrix *access_matrix)
5102 VEC (tree,heap) *lambda_parameters = AM_PARAMETERS (access_matrix);
5103 tree lambda_parameter;
5105 for (i = 0; VEC_iterate (tree, lambda_parameters, i, lambda_parameter); i++)
5106 if (lambda_parameter == parameter)
5107 return i + AM_NB_INDUCTION_VARS (access_matrix);