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 op0 = TREE_OPERAND (op0, 0);
555 if (!handled_component_p (op0))
558 base = get_inner_reference (op0, &pbitsize, &pbitpos, &poffset,
559 &pmode, &punsignedp, &pvolatilep, false);
561 if (pbitpos % BITS_PER_UNIT != 0)
563 base = build_fold_addr_expr (base);
564 off0 = ssize_int (pbitpos / BITS_PER_UNIT);
568 split_constant_offset (poffset, &poffset, &off1);
569 off0 = size_binop (PLUS_EXPR, off0, off1);
570 if (POINTER_TYPE_P (TREE_TYPE (base)))
571 base = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (base),
572 base, fold_convert (sizetype, poffset));
574 base = fold_build2 (PLUS_EXPR, TREE_TYPE (base), base,
575 fold_convert (TREE_TYPE (base), poffset));
578 var0 = fold_convert (type, base);
580 /* If variable length types are involved, punt, otherwise casts
581 might be converted into ARRAY_REFs in gimplify_conversion.
582 To compute that ARRAY_REF's element size TYPE_SIZE_UNIT, which
583 possibly no longer appears in current GIMPLE, might resurface.
584 This perhaps could run
585 if (CONVERT_EXPR_P (var0))
587 gimplify_conversion (&var0);
588 // Attempt to fill in any within var0 found ARRAY_REF's
589 // element size from corresponding op embedded ARRAY_REF,
590 // if unsuccessful, just punt.
592 while (POINTER_TYPE_P (type))
593 type = TREE_TYPE (type);
594 if (int_size_in_bytes (type) < 0)
604 gimple def_stmt = SSA_NAME_DEF_STMT (op0);
605 enum tree_code subcode;
607 if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
610 var0 = gimple_assign_rhs1 (def_stmt);
611 subcode = gimple_assign_rhs_code (def_stmt);
612 var1 = gimple_assign_rhs2 (def_stmt);
614 return split_constant_offset_1 (type, var0, subcode, var1, var, off);
622 /* Expresses EXP as VAR + OFF, where off is a constant. The type of OFF
623 will be ssizetype. */
626 split_constant_offset (tree exp, tree *var, tree *off)
628 tree type = TREE_TYPE (exp), otype, op0, op1, e, o;
632 *off = ssize_int (0);
635 if (automatically_generated_chrec_p (exp))
638 otype = TREE_TYPE (exp);
639 code = TREE_CODE (exp);
640 extract_ops_from_tree (exp, &code, &op0, &op1);
641 if (split_constant_offset_1 (otype, op0, code, op1, &e, &o))
643 *var = fold_convert (type, e);
648 /* Returns the address ADDR of an object in a canonical shape (without nop
649 casts, and with type of pointer to the object). */
652 canonicalize_base_object_address (tree addr)
658 /* The base address may be obtained by casting from integer, in that case
660 if (!POINTER_TYPE_P (TREE_TYPE (addr)))
663 if (TREE_CODE (addr) != ADDR_EXPR)
666 return build_fold_addr_expr (TREE_OPERAND (addr, 0));
669 /* Analyzes the behavior of the memory reference DR in the innermost loop that
673 dr_analyze_innermost (struct data_reference *dr)
675 gimple stmt = DR_STMT (dr);
676 struct loop *loop = loop_containing_stmt (stmt);
677 tree ref = DR_REF (dr);
678 HOST_WIDE_INT pbitsize, pbitpos;
680 enum machine_mode pmode;
681 int punsignedp, pvolatilep;
682 affine_iv base_iv, offset_iv;
683 tree init, dinit, step;
685 if (dump_file && (dump_flags & TDF_DETAILS))
686 fprintf (dump_file, "analyze_innermost: ");
688 base = get_inner_reference (ref, &pbitsize, &pbitpos, &poffset,
689 &pmode, &punsignedp, &pvolatilep, false);
690 gcc_assert (base != NULL_TREE);
692 if (pbitpos % BITS_PER_UNIT != 0)
694 if (dump_file && (dump_flags & TDF_DETAILS))
695 fprintf (dump_file, "failed: bit offset alignment.\n");
699 base = build_fold_addr_expr (base);
700 if (!simple_iv (loop, stmt, base, &base_iv, false))
702 if (dump_file && (dump_flags & TDF_DETAILS))
703 fprintf (dump_file, "failed: evolution of base is not affine.\n");
708 offset_iv.base = ssize_int (0);
709 offset_iv.step = ssize_int (0);
711 else if (!simple_iv (loop, stmt, poffset, &offset_iv, false))
713 if (dump_file && (dump_flags & TDF_DETAILS))
714 fprintf (dump_file, "failed: evolution of offset is not affine.\n");
718 init = ssize_int (pbitpos / BITS_PER_UNIT);
719 split_constant_offset (base_iv.base, &base_iv.base, &dinit);
720 init = size_binop (PLUS_EXPR, init, dinit);
721 split_constant_offset (offset_iv.base, &offset_iv.base, &dinit);
722 init = size_binop (PLUS_EXPR, init, dinit);
724 step = size_binop (PLUS_EXPR,
725 fold_convert (ssizetype, base_iv.step),
726 fold_convert (ssizetype, offset_iv.step));
728 DR_BASE_ADDRESS (dr) = canonicalize_base_object_address (base_iv.base);
730 DR_OFFSET (dr) = fold_convert (ssizetype, offset_iv.base);
734 DR_ALIGNED_TO (dr) = size_int (highest_pow2_factor (offset_iv.base));
736 if (dump_file && (dump_flags & TDF_DETAILS))
737 fprintf (dump_file, "success.\n");
740 /* Determines the base object and the list of indices of memory reference
741 DR, analyzed in loop nest NEST. */
744 dr_analyze_indices (struct data_reference *dr, struct loop *nest)
746 gimple stmt = DR_STMT (dr);
747 struct loop *loop = loop_containing_stmt (stmt);
748 VEC (tree, heap) *access_fns = NULL;
749 tree ref = unshare_expr (DR_REF (dr)), aref = ref, op;
750 tree base, off, access_fn;
751 basic_block before_loop = block_before_loop (nest);
753 while (handled_component_p (aref))
755 if (TREE_CODE (aref) == ARRAY_REF)
757 op = TREE_OPERAND (aref, 1);
758 access_fn = analyze_scalar_evolution (loop, op);
759 access_fn = instantiate_scev (before_loop, loop, access_fn);
760 VEC_safe_push (tree, heap, access_fns, access_fn);
762 TREE_OPERAND (aref, 1) = build_int_cst (TREE_TYPE (op), 0);
765 aref = TREE_OPERAND (aref, 0);
768 if (INDIRECT_REF_P (aref))
770 op = TREE_OPERAND (aref, 0);
771 access_fn = analyze_scalar_evolution (loop, op);
772 access_fn = instantiate_scev (before_loop, loop, access_fn);
773 base = initial_condition (access_fn);
774 split_constant_offset (base, &base, &off);
775 access_fn = chrec_replace_initial_condition (access_fn,
776 fold_convert (TREE_TYPE (base), off));
778 TREE_OPERAND (aref, 0) = base;
779 VEC_safe_push (tree, heap, access_fns, access_fn);
782 DR_BASE_OBJECT (dr) = ref;
783 DR_ACCESS_FNS (dr) = access_fns;
786 /* Extracts the alias analysis information from the memory reference DR. */
789 dr_analyze_alias (struct data_reference *dr)
791 gimple stmt = DR_STMT (dr);
792 tree ref = DR_REF (dr);
793 tree base = get_base_address (ref), addr, smt = NULL_TREE;
800 else if (INDIRECT_REF_P (base))
802 addr = TREE_OPERAND (base, 0);
803 if (TREE_CODE (addr) == SSA_NAME)
805 smt = symbol_mem_tag (SSA_NAME_VAR (addr));
806 DR_PTR_INFO (dr) = SSA_NAME_PTR_INFO (addr);
810 DR_SYMBOL_TAG (dr) = smt;
812 vops = BITMAP_ALLOC (NULL);
813 FOR_EACH_SSA_TREE_OPERAND (op, stmt, it, SSA_OP_VIRTUAL_USES)
815 bitmap_set_bit (vops, DECL_UID (SSA_NAME_VAR (op)));
821 /* Returns true if the address of DR is invariant. */
824 dr_address_invariant_p (struct data_reference *dr)
829 for (i = 0; VEC_iterate (tree, DR_ACCESS_FNS (dr), i, idx); i++)
830 if (tree_contains_chrecs (idx, NULL))
836 /* Frees data reference DR. */
839 free_data_ref (data_reference_p dr)
841 BITMAP_FREE (DR_VOPS (dr));
842 VEC_free (tree, heap, DR_ACCESS_FNS (dr));
846 /* Analyzes memory reference MEMREF accessed in STMT. The reference
847 is read if IS_READ is true, write otherwise. Returns the
848 data_reference description of MEMREF. NEST is the outermost loop of the
849 loop nest in that the reference should be analyzed. */
851 struct data_reference *
852 create_data_ref (struct loop *nest, tree memref, gimple stmt, bool is_read)
854 struct data_reference *dr;
856 if (dump_file && (dump_flags & TDF_DETAILS))
858 fprintf (dump_file, "Creating dr for ");
859 print_generic_expr (dump_file, memref, TDF_SLIM);
860 fprintf (dump_file, "\n");
863 dr = XCNEW (struct data_reference);
865 DR_REF (dr) = memref;
866 DR_IS_READ (dr) = is_read;
868 dr_analyze_innermost (dr);
869 dr_analyze_indices (dr, nest);
870 dr_analyze_alias (dr);
872 if (dump_file && (dump_flags & TDF_DETAILS))
874 fprintf (dump_file, "\tbase_address: ");
875 print_generic_expr (dump_file, DR_BASE_ADDRESS (dr), TDF_SLIM);
876 fprintf (dump_file, "\n\toffset from base address: ");
877 print_generic_expr (dump_file, DR_OFFSET (dr), TDF_SLIM);
878 fprintf (dump_file, "\n\tconstant offset from base address: ");
879 print_generic_expr (dump_file, DR_INIT (dr), TDF_SLIM);
880 fprintf (dump_file, "\n\tstep: ");
881 print_generic_expr (dump_file, DR_STEP (dr), TDF_SLIM);
882 fprintf (dump_file, "\n\taligned to: ");
883 print_generic_expr (dump_file, DR_ALIGNED_TO (dr), TDF_SLIM);
884 fprintf (dump_file, "\n\tbase_object: ");
885 print_generic_expr (dump_file, DR_BASE_OBJECT (dr), TDF_SLIM);
886 fprintf (dump_file, "\n\tsymbol tag: ");
887 print_generic_expr (dump_file, DR_SYMBOL_TAG (dr), TDF_SLIM);
888 fprintf (dump_file, "\n");
894 /* Returns true if FNA == FNB. */
897 affine_function_equal_p (affine_fn fna, affine_fn fnb)
899 unsigned i, n = VEC_length (tree, fna);
901 if (n != VEC_length (tree, fnb))
904 for (i = 0; i < n; i++)
905 if (!operand_equal_p (VEC_index (tree, fna, i),
906 VEC_index (tree, fnb, i), 0))
912 /* If all the functions in CF are the same, returns one of them,
913 otherwise returns NULL. */
916 common_affine_function (conflict_function *cf)
921 if (!CF_NONTRIVIAL_P (cf))
926 for (i = 1; i < cf->n; i++)
927 if (!affine_function_equal_p (comm, cf->fns[i]))
933 /* Returns the base of the affine function FN. */
936 affine_function_base (affine_fn fn)
938 return VEC_index (tree, fn, 0);
941 /* Returns true if FN is a constant. */
944 affine_function_constant_p (affine_fn fn)
949 for (i = 1; VEC_iterate (tree, fn, i, coef); i++)
950 if (!integer_zerop (coef))
956 /* Returns true if FN is the zero constant function. */
959 affine_function_zero_p (affine_fn fn)
961 return (integer_zerop (affine_function_base (fn))
962 && affine_function_constant_p (fn));
965 /* Returns a signed integer type with the largest precision from TA
969 signed_type_for_types (tree ta, tree tb)
971 if (TYPE_PRECISION (ta) > TYPE_PRECISION (tb))
972 return signed_type_for (ta);
974 return signed_type_for (tb);
977 /* Applies operation OP on affine functions FNA and FNB, and returns the
981 affine_fn_op (enum tree_code op, affine_fn fna, affine_fn fnb)
987 if (VEC_length (tree, fnb) > VEC_length (tree, fna))
989 n = VEC_length (tree, fna);
990 m = VEC_length (tree, fnb);
994 n = VEC_length (tree, fnb);
995 m = VEC_length (tree, fna);
998 ret = VEC_alloc (tree, heap, m);
999 for (i = 0; i < n; i++)
1001 tree type = signed_type_for_types (TREE_TYPE (VEC_index (tree, fna, i)),
1002 TREE_TYPE (VEC_index (tree, fnb, i)));
1004 VEC_quick_push (tree, ret,
1005 fold_build2 (op, type,
1006 VEC_index (tree, fna, i),
1007 VEC_index (tree, fnb, i)));
1010 for (; VEC_iterate (tree, fna, i, coef); i++)
1011 VEC_quick_push (tree, ret,
1012 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1013 coef, integer_zero_node));
1014 for (; VEC_iterate (tree, fnb, i, coef); i++)
1015 VEC_quick_push (tree, ret,
1016 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1017 integer_zero_node, coef));
1022 /* Returns the sum of affine functions FNA and FNB. */
1025 affine_fn_plus (affine_fn fna, affine_fn fnb)
1027 return affine_fn_op (PLUS_EXPR, fna, fnb);
1030 /* Returns the difference of affine functions FNA and FNB. */
1033 affine_fn_minus (affine_fn fna, affine_fn fnb)
1035 return affine_fn_op (MINUS_EXPR, fna, fnb);
1038 /* Frees affine function FN. */
1041 affine_fn_free (affine_fn fn)
1043 VEC_free (tree, heap, fn);
1046 /* Determine for each subscript in the data dependence relation DDR
1050 compute_subscript_distance (struct data_dependence_relation *ddr)
1052 conflict_function *cf_a, *cf_b;
1053 affine_fn fn_a, fn_b, diff;
1055 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
1059 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
1061 struct subscript *subscript;
1063 subscript = DDR_SUBSCRIPT (ddr, i);
1064 cf_a = SUB_CONFLICTS_IN_A (subscript);
1065 cf_b = SUB_CONFLICTS_IN_B (subscript);
1067 fn_a = common_affine_function (cf_a);
1068 fn_b = common_affine_function (cf_b);
1071 SUB_DISTANCE (subscript) = chrec_dont_know;
1074 diff = affine_fn_minus (fn_a, fn_b);
1076 if (affine_function_constant_p (diff))
1077 SUB_DISTANCE (subscript) = affine_function_base (diff);
1079 SUB_DISTANCE (subscript) = chrec_dont_know;
1081 affine_fn_free (diff);
1086 /* Returns the conflict function for "unknown". */
1088 static conflict_function *
1089 conflict_fn_not_known (void)
1091 conflict_function *fn = XCNEW (conflict_function);
1097 /* Returns the conflict function for "independent". */
1099 static conflict_function *
1100 conflict_fn_no_dependence (void)
1102 conflict_function *fn = XCNEW (conflict_function);
1103 fn->n = NO_DEPENDENCE;
1108 /* Returns true if the address of OBJ is invariant in LOOP. */
1111 object_address_invariant_in_loop_p (const struct loop *loop, const_tree obj)
1113 while (handled_component_p (obj))
1115 if (TREE_CODE (obj) == ARRAY_REF)
1117 /* Index of the ARRAY_REF was zeroed in analyze_indices, thus we only
1118 need to check the stride and the lower bound of the reference. */
1119 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1121 || chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 3),
1125 else if (TREE_CODE (obj) == COMPONENT_REF)
1127 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1131 obj = TREE_OPERAND (obj, 0);
1134 if (!INDIRECT_REF_P (obj))
1137 return !chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 0),
1141 /* Returns true if A and B are accesses to different objects, or to different
1142 fields of the same object. */
1145 disjoint_objects_p (tree a, tree b)
1147 tree base_a, base_b;
1148 VEC (tree, heap) *comp_a = NULL, *comp_b = NULL;
1151 base_a = get_base_address (a);
1152 base_b = get_base_address (b);
1156 && base_a != base_b)
1159 if (!operand_equal_p (base_a, base_b, 0))
1162 /* Compare the component references of A and B. We must start from the inner
1163 ones, so record them to the vector first. */
1164 while (handled_component_p (a))
1166 VEC_safe_push (tree, heap, comp_a, a);
1167 a = TREE_OPERAND (a, 0);
1169 while (handled_component_p (b))
1171 VEC_safe_push (tree, heap, comp_b, b);
1172 b = TREE_OPERAND (b, 0);
1178 if (VEC_length (tree, comp_a) == 0
1179 || VEC_length (tree, comp_b) == 0)
1182 a = VEC_pop (tree, comp_a);
1183 b = VEC_pop (tree, comp_b);
1185 /* Real and imaginary part of a variable do not alias. */
1186 if ((TREE_CODE (a) == REALPART_EXPR
1187 && TREE_CODE (b) == IMAGPART_EXPR)
1188 || (TREE_CODE (a) == IMAGPART_EXPR
1189 && TREE_CODE (b) == REALPART_EXPR))
1195 if (TREE_CODE (a) != TREE_CODE (b))
1198 /* Nothing to do for ARRAY_REFs, as the indices of array_refs in
1199 DR_BASE_OBJECT are always zero. */
1200 if (TREE_CODE (a) == ARRAY_REF)
1202 else if (TREE_CODE (a) == COMPONENT_REF)
1204 if (operand_equal_p (TREE_OPERAND (a, 1), TREE_OPERAND (b, 1), 0))
1207 /* Different fields of unions may overlap. */
1208 base_a = TREE_OPERAND (a, 0);
1209 if (TREE_CODE (TREE_TYPE (base_a)) == UNION_TYPE)
1212 /* Different fields of structures cannot. */
1220 VEC_free (tree, heap, comp_a);
1221 VEC_free (tree, heap, comp_b);
1226 /* Returns false if we can prove that data references A and B do not alias,
1230 dr_may_alias_p (const struct data_reference *a, const struct data_reference *b)
1232 const_tree addr_a = DR_BASE_ADDRESS (a);
1233 const_tree addr_b = DR_BASE_ADDRESS (b);
1234 const_tree type_a, type_b;
1235 const_tree decl_a = NULL_TREE, decl_b = NULL_TREE;
1237 /* If the sets of virtual operands are disjoint, the memory references do not
1239 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
1242 /* If the accessed objects are disjoint, the memory references do not
1244 if (disjoint_objects_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b)))
1247 if (!addr_a || !addr_b)
1250 /* If the references are based on different static objects, they cannot alias
1251 (PTA should be able to disambiguate such accesses, but often it fails to,
1252 since currently we cannot distinguish between pointer and offset in pointer
1254 if (TREE_CODE (addr_a) == ADDR_EXPR
1255 && TREE_CODE (addr_b) == ADDR_EXPR)
1256 return TREE_OPERAND (addr_a, 0) == TREE_OPERAND (addr_b, 0);
1258 /* An instruction writing through a restricted pointer is "independent" of any
1259 instruction reading or writing through a different restricted pointer,
1260 in the same block/scope. */
1262 type_a = TREE_TYPE (addr_a);
1263 type_b = TREE_TYPE (addr_b);
1264 gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b));
1266 if (TREE_CODE (addr_a) == SSA_NAME)
1267 decl_a = SSA_NAME_VAR (addr_a);
1268 if (TREE_CODE (addr_b) == SSA_NAME)
1269 decl_b = SSA_NAME_VAR (addr_b);
1271 if (TYPE_RESTRICT (type_a) && TYPE_RESTRICT (type_b)
1272 && (!DR_IS_READ (a) || !DR_IS_READ (b))
1273 && decl_a && DECL_P (decl_a)
1274 && decl_b && DECL_P (decl_b)
1276 && TREE_CODE (DECL_CONTEXT (decl_a)) == FUNCTION_DECL
1277 && DECL_CONTEXT (decl_a) == DECL_CONTEXT (decl_b))
1283 static void compute_self_dependence (struct data_dependence_relation *);
1285 /* Initialize a data dependence relation between data accesses A and
1286 B. NB_LOOPS is the number of loops surrounding the references: the
1287 size of the classic distance/direction vectors. */
1289 static struct data_dependence_relation *
1290 initialize_data_dependence_relation (struct data_reference *a,
1291 struct data_reference *b,
1292 VEC (loop_p, heap) *loop_nest)
1294 struct data_dependence_relation *res;
1297 res = XNEW (struct data_dependence_relation);
1300 DDR_LOOP_NEST (res) = NULL;
1301 DDR_REVERSED_P (res) = false;
1302 DDR_SUBSCRIPTS (res) = NULL;
1303 DDR_DIR_VECTS (res) = NULL;
1304 DDR_DIST_VECTS (res) = NULL;
1306 if (a == NULL || b == NULL)
1308 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1312 /* If the data references do not alias, then they are independent. */
1313 if (!dr_may_alias_p (a, b))
1315 DDR_ARE_DEPENDENT (res) = chrec_known;
1319 /* When the references are exactly the same, don't spend time doing
1320 the data dependence tests, just initialize the ddr and return. */
1321 if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
1323 DDR_AFFINE_P (res) = true;
1324 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1325 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1326 DDR_LOOP_NEST (res) = loop_nest;
1327 DDR_INNER_LOOP (res) = 0;
1328 DDR_SELF_REFERENCE (res) = true;
1329 compute_self_dependence (res);
1333 /* If the references do not access the same object, we do not know
1334 whether they alias or not. */
1335 if (!operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0))
1337 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1341 /* If the base of the object is not invariant in the loop nest, we cannot
1342 analyze it. TODO -- in fact, it would suffice to record that there may
1343 be arbitrary dependences in the loops where the base object varies. */
1344 if (!object_address_invariant_in_loop_p (VEC_index (loop_p, loop_nest, 0),
1345 DR_BASE_OBJECT (a)))
1347 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1351 gcc_assert (DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b));
1353 DDR_AFFINE_P (res) = true;
1354 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1355 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1356 DDR_LOOP_NEST (res) = loop_nest;
1357 DDR_INNER_LOOP (res) = 0;
1358 DDR_SELF_REFERENCE (res) = false;
1360 for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
1362 struct subscript *subscript;
1364 subscript = XNEW (struct subscript);
1365 SUB_CONFLICTS_IN_A (subscript) = conflict_fn_not_known ();
1366 SUB_CONFLICTS_IN_B (subscript) = conflict_fn_not_known ();
1367 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
1368 SUB_DISTANCE (subscript) = chrec_dont_know;
1369 VEC_safe_push (subscript_p, heap, DDR_SUBSCRIPTS (res), subscript);
1375 /* Frees memory used by the conflict function F. */
1378 free_conflict_function (conflict_function *f)
1382 if (CF_NONTRIVIAL_P (f))
1384 for (i = 0; i < f->n; i++)
1385 affine_fn_free (f->fns[i]);
1390 /* Frees memory used by SUBSCRIPTS. */
1393 free_subscripts (VEC (subscript_p, heap) *subscripts)
1398 for (i = 0; VEC_iterate (subscript_p, subscripts, i, s); i++)
1400 free_conflict_function (s->conflicting_iterations_in_a);
1401 free_conflict_function (s->conflicting_iterations_in_b);
1404 VEC_free (subscript_p, heap, subscripts);
1407 /* Set DDR_ARE_DEPENDENT to CHREC and finalize the subscript overlap
1411 finalize_ddr_dependent (struct data_dependence_relation *ddr,
1414 if (dump_file && (dump_flags & TDF_DETAILS))
1416 fprintf (dump_file, "(dependence classified: ");
1417 print_generic_expr (dump_file, chrec, 0);
1418 fprintf (dump_file, ")\n");
1421 DDR_ARE_DEPENDENT (ddr) = chrec;
1422 free_subscripts (DDR_SUBSCRIPTS (ddr));
1423 DDR_SUBSCRIPTS (ddr) = NULL;
1426 /* The dependence relation DDR cannot be represented by a distance
1430 non_affine_dependence_relation (struct data_dependence_relation *ddr)
1432 if (dump_file && (dump_flags & TDF_DETAILS))
1433 fprintf (dump_file, "(Dependence relation cannot be represented by distance vector.) \n");
1435 DDR_AFFINE_P (ddr) = false;
1440 /* This section contains the classic Banerjee tests. */
1442 /* Returns true iff CHREC_A and CHREC_B are not dependent on any index
1443 variables, i.e., if the ZIV (Zero Index Variable) test is true. */
1446 ziv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1448 return (evolution_function_is_constant_p (chrec_a)
1449 && evolution_function_is_constant_p (chrec_b));
1452 /* Returns true iff CHREC_A and CHREC_B are dependent on an index
1453 variable, i.e., if the SIV (Single Index Variable) test is true. */
1456 siv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1458 if ((evolution_function_is_constant_p (chrec_a)
1459 && evolution_function_is_univariate_p (chrec_b))
1460 || (evolution_function_is_constant_p (chrec_b)
1461 && evolution_function_is_univariate_p (chrec_a)))
1464 if (evolution_function_is_univariate_p (chrec_a)
1465 && evolution_function_is_univariate_p (chrec_b))
1467 switch (TREE_CODE (chrec_a))
1469 case POLYNOMIAL_CHREC:
1470 switch (TREE_CODE (chrec_b))
1472 case POLYNOMIAL_CHREC:
1473 if (CHREC_VARIABLE (chrec_a) != CHREC_VARIABLE (chrec_b))
1488 /* Creates a conflict function with N dimensions. The affine functions
1489 in each dimension follow. */
1491 static conflict_function *
1492 conflict_fn (unsigned n, ...)
1495 conflict_function *ret = XCNEW (conflict_function);
1498 gcc_assert (0 < n && n <= MAX_DIM);
1502 for (i = 0; i < n; i++)
1503 ret->fns[i] = va_arg (ap, affine_fn);
1509 /* Returns constant affine function with value CST. */
1512 affine_fn_cst (tree cst)
1514 affine_fn fn = VEC_alloc (tree, heap, 1);
1515 VEC_quick_push (tree, fn, cst);
1519 /* Returns affine function with single variable, CST + COEF * x_DIM. */
1522 affine_fn_univar (tree cst, unsigned dim, tree coef)
1524 affine_fn fn = VEC_alloc (tree, heap, dim + 1);
1527 gcc_assert (dim > 0);
1528 VEC_quick_push (tree, fn, cst);
1529 for (i = 1; i < dim; i++)
1530 VEC_quick_push (tree, fn, integer_zero_node);
1531 VEC_quick_push (tree, fn, coef);
1535 /* Analyze a ZIV (Zero Index Variable) subscript. *OVERLAPS_A and
1536 *OVERLAPS_B are initialized to the functions that describe the
1537 relation between the elements accessed twice by CHREC_A and
1538 CHREC_B. For k >= 0, the following property is verified:
1540 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1543 analyze_ziv_subscript (tree chrec_a,
1545 conflict_function **overlaps_a,
1546 conflict_function **overlaps_b,
1547 tree *last_conflicts)
1549 tree type, difference;
1550 dependence_stats.num_ziv++;
1552 if (dump_file && (dump_flags & TDF_DETAILS))
1553 fprintf (dump_file, "(analyze_ziv_subscript \n");
1555 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1556 chrec_a = chrec_convert (type, chrec_a, NULL);
1557 chrec_b = chrec_convert (type, chrec_b, NULL);
1558 difference = chrec_fold_minus (type, chrec_a, chrec_b);
1560 switch (TREE_CODE (difference))
1563 if (integer_zerop (difference))
1565 /* The difference is equal to zero: the accessed index
1566 overlaps for each iteration in the loop. */
1567 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1568 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
1569 *last_conflicts = chrec_dont_know;
1570 dependence_stats.num_ziv_dependent++;
1574 /* The accesses do not overlap. */
1575 *overlaps_a = conflict_fn_no_dependence ();
1576 *overlaps_b = conflict_fn_no_dependence ();
1577 *last_conflicts = integer_zero_node;
1578 dependence_stats.num_ziv_independent++;
1583 /* We're not sure whether the indexes overlap. For the moment,
1584 conservatively answer "don't know". */
1585 if (dump_file && (dump_flags & TDF_DETAILS))
1586 fprintf (dump_file, "ziv test failed: difference is non-integer.\n");
1588 *overlaps_a = conflict_fn_not_known ();
1589 *overlaps_b = conflict_fn_not_known ();
1590 *last_conflicts = chrec_dont_know;
1591 dependence_stats.num_ziv_unimplemented++;
1595 if (dump_file && (dump_flags & TDF_DETAILS))
1596 fprintf (dump_file, ")\n");
1599 /* Sets NIT to the estimated number of executions of the statements in
1600 LOOP. If CONSERVATIVE is true, we must be sure that NIT is at least as
1601 large as the number of iterations. If we have no reliable estimate,
1602 the function returns false, otherwise returns true. */
1605 estimated_loop_iterations (struct loop *loop, bool conservative,
1608 estimate_numbers_of_iterations_loop (loop);
1611 if (!loop->any_upper_bound)
1614 *nit = loop->nb_iterations_upper_bound;
1618 if (!loop->any_estimate)
1621 *nit = loop->nb_iterations_estimate;
1627 /* Similar to estimated_loop_iterations, but returns the estimate only
1628 if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
1629 on the number of iterations of LOOP could not be derived, returns -1. */
1632 estimated_loop_iterations_int (struct loop *loop, bool conservative)
1635 HOST_WIDE_INT hwi_nit;
1637 if (!estimated_loop_iterations (loop, conservative, &nit))
1640 if (!double_int_fits_in_shwi_p (nit))
1642 hwi_nit = double_int_to_shwi (nit);
1644 return hwi_nit < 0 ? -1 : hwi_nit;
1647 /* Similar to estimated_loop_iterations, but returns the estimate as a tree,
1648 and only if it fits to the int type. If this is not the case, or the
1649 estimate on the number of iterations of LOOP could not be derived, returns
1653 estimated_loop_iterations_tree (struct loop *loop, bool conservative)
1658 if (!estimated_loop_iterations (loop, conservative, &nit))
1659 return chrec_dont_know;
1661 type = lang_hooks.types.type_for_size (INT_TYPE_SIZE, true);
1662 if (!double_int_fits_to_tree_p (type, nit))
1663 return chrec_dont_know;
1665 return double_int_to_tree (type, nit);
1668 /* Analyze a SIV (Single Index Variable) subscript where CHREC_A is a
1669 constant, and CHREC_B is an affine function. *OVERLAPS_A and
1670 *OVERLAPS_B are initialized to the functions that describe the
1671 relation between the elements accessed twice by CHREC_A and
1672 CHREC_B. For k >= 0, the following property is verified:
1674 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1677 analyze_siv_subscript_cst_affine (tree chrec_a,
1679 conflict_function **overlaps_a,
1680 conflict_function **overlaps_b,
1681 tree *last_conflicts)
1683 bool value0, value1, value2;
1684 tree type, difference, tmp;
1686 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1687 chrec_a = chrec_convert (type, chrec_a, NULL);
1688 chrec_b = chrec_convert (type, chrec_b, NULL);
1689 difference = chrec_fold_minus (type, initial_condition (chrec_b), chrec_a);
1691 if (!chrec_is_positive (initial_condition (difference), &value0))
1693 if (dump_file && (dump_flags & TDF_DETAILS))
1694 fprintf (dump_file, "siv test failed: chrec is not positive.\n");
1696 dependence_stats.num_siv_unimplemented++;
1697 *overlaps_a = conflict_fn_not_known ();
1698 *overlaps_b = conflict_fn_not_known ();
1699 *last_conflicts = chrec_dont_know;
1704 if (value0 == false)
1706 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value1))
1708 if (dump_file && (dump_flags & TDF_DETAILS))
1709 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1711 *overlaps_a = conflict_fn_not_known ();
1712 *overlaps_b = conflict_fn_not_known ();
1713 *last_conflicts = chrec_dont_know;
1714 dependence_stats.num_siv_unimplemented++;
1723 chrec_b = {10, +, 1}
1726 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1728 HOST_WIDE_INT numiter;
1729 struct loop *loop = get_chrec_loop (chrec_b);
1731 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1732 tmp = fold_build2 (EXACT_DIV_EXPR, type,
1733 fold_build1 (ABS_EXPR, type, difference),
1734 CHREC_RIGHT (chrec_b));
1735 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1736 *last_conflicts = integer_one_node;
1739 /* Perform weak-zero siv test to see if overlap is
1740 outside the loop bounds. */
1741 numiter = estimated_loop_iterations_int (loop, false);
1744 && compare_tree_int (tmp, numiter) > 0)
1746 free_conflict_function (*overlaps_a);
1747 free_conflict_function (*overlaps_b);
1748 *overlaps_a = conflict_fn_no_dependence ();
1749 *overlaps_b = conflict_fn_no_dependence ();
1750 *last_conflicts = integer_zero_node;
1751 dependence_stats.num_siv_independent++;
1754 dependence_stats.num_siv_dependent++;
1758 /* When the step does not divide the difference, there are
1762 *overlaps_a = conflict_fn_no_dependence ();
1763 *overlaps_b = conflict_fn_no_dependence ();
1764 *last_conflicts = integer_zero_node;
1765 dependence_stats.num_siv_independent++;
1774 chrec_b = {10, +, -1}
1776 In this case, chrec_a will not overlap with chrec_b. */
1777 *overlaps_a = conflict_fn_no_dependence ();
1778 *overlaps_b = conflict_fn_no_dependence ();
1779 *last_conflicts = integer_zero_node;
1780 dependence_stats.num_siv_independent++;
1787 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value2))
1789 if (dump_file && (dump_flags & TDF_DETAILS))
1790 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1792 *overlaps_a = conflict_fn_not_known ();
1793 *overlaps_b = conflict_fn_not_known ();
1794 *last_conflicts = chrec_dont_know;
1795 dependence_stats.num_siv_unimplemented++;
1800 if (value2 == false)
1804 chrec_b = {10, +, -1}
1806 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1808 HOST_WIDE_INT numiter;
1809 struct loop *loop = get_chrec_loop (chrec_b);
1811 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1812 tmp = fold_build2 (EXACT_DIV_EXPR, type, difference,
1813 CHREC_RIGHT (chrec_b));
1814 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1815 *last_conflicts = integer_one_node;
1817 /* Perform weak-zero siv test to see if overlap is
1818 outside the loop bounds. */
1819 numiter = estimated_loop_iterations_int (loop, false);
1822 && compare_tree_int (tmp, numiter) > 0)
1824 free_conflict_function (*overlaps_a);
1825 free_conflict_function (*overlaps_b);
1826 *overlaps_a = conflict_fn_no_dependence ();
1827 *overlaps_b = conflict_fn_no_dependence ();
1828 *last_conflicts = integer_zero_node;
1829 dependence_stats.num_siv_independent++;
1832 dependence_stats.num_siv_dependent++;
1836 /* When the step does not divide the difference, there
1840 *overlaps_a = conflict_fn_no_dependence ();
1841 *overlaps_b = conflict_fn_no_dependence ();
1842 *last_conflicts = integer_zero_node;
1843 dependence_stats.num_siv_independent++;
1853 In this case, chrec_a will not overlap with chrec_b. */
1854 *overlaps_a = conflict_fn_no_dependence ();
1855 *overlaps_b = conflict_fn_no_dependence ();
1856 *last_conflicts = integer_zero_node;
1857 dependence_stats.num_siv_independent++;
1865 /* Helper recursive function for initializing the matrix A. Returns
1866 the initial value of CHREC. */
1869 initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
1873 switch (TREE_CODE (chrec))
1875 case POLYNOMIAL_CHREC:
1876 gcc_assert (TREE_CODE (CHREC_RIGHT (chrec)) == INTEGER_CST);
1878 A[index][0] = mult * int_cst_value (CHREC_RIGHT (chrec));
1879 return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult);
1885 tree op0 = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1886 tree op1 = initialize_matrix_A (A, TREE_OPERAND (chrec, 1), index, mult);
1888 return chrec_fold_op (TREE_CODE (chrec), chrec_type (chrec), op0, op1);
1893 tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1894 return chrec_convert (chrec_type (chrec), op, NULL);
1906 #define FLOOR_DIV(x,y) ((x) / (y))
1908 /* Solves the special case of the Diophantine equation:
1909 | {0, +, STEP_A}_x (OVERLAPS_A) = {0, +, STEP_B}_y (OVERLAPS_B)
1911 Computes the descriptions OVERLAPS_A and OVERLAPS_B. NITER is the
1912 number of iterations that loops X and Y run. The overlaps will be
1913 constructed as evolutions in dimension DIM. */
1916 compute_overlap_steps_for_affine_univar (int niter, int step_a, int step_b,
1917 affine_fn *overlaps_a,
1918 affine_fn *overlaps_b,
1919 tree *last_conflicts, int dim)
1921 if (((step_a > 0 && step_b > 0)
1922 || (step_a < 0 && step_b < 0)))
1924 int step_overlaps_a, step_overlaps_b;
1925 int gcd_steps_a_b, last_conflict, tau2;
1927 gcd_steps_a_b = gcd (step_a, step_b);
1928 step_overlaps_a = step_b / gcd_steps_a_b;
1929 step_overlaps_b = step_a / gcd_steps_a_b;
1933 tau2 = FLOOR_DIV (niter, step_overlaps_a);
1934 tau2 = MIN (tau2, FLOOR_DIV (niter, step_overlaps_b));
1935 last_conflict = tau2;
1936 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
1939 *last_conflicts = chrec_dont_know;
1941 *overlaps_a = affine_fn_univar (integer_zero_node, dim,
1942 build_int_cst (NULL_TREE,
1944 *overlaps_b = affine_fn_univar (integer_zero_node, dim,
1945 build_int_cst (NULL_TREE,
1951 *overlaps_a = affine_fn_cst (integer_zero_node);
1952 *overlaps_b = affine_fn_cst (integer_zero_node);
1953 *last_conflicts = integer_zero_node;
1957 /* Solves the special case of a Diophantine equation where CHREC_A is
1958 an affine bivariate function, and CHREC_B is an affine univariate
1959 function. For example,
1961 | {{0, +, 1}_x, +, 1335}_y = {0, +, 1336}_z
1963 has the following overlapping functions:
1965 | x (t, u, v) = {{0, +, 1336}_t, +, 1}_v
1966 | y (t, u, v) = {{0, +, 1336}_u, +, 1}_v
1967 | z (t, u, v) = {{{0, +, 1}_t, +, 1335}_u, +, 1}_v
1969 FORNOW: This is a specialized implementation for a case occurring in
1970 a common benchmark. Implement the general algorithm. */
1973 compute_overlap_steps_for_affine_1_2 (tree chrec_a, tree chrec_b,
1974 conflict_function **overlaps_a,
1975 conflict_function **overlaps_b,
1976 tree *last_conflicts)
1978 bool xz_p, yz_p, xyz_p;
1979 int step_x, step_y, step_z;
1980 HOST_WIDE_INT niter_x, niter_y, niter_z, niter;
1981 affine_fn overlaps_a_xz, overlaps_b_xz;
1982 affine_fn overlaps_a_yz, overlaps_b_yz;
1983 affine_fn overlaps_a_xyz, overlaps_b_xyz;
1984 affine_fn ova1, ova2, ovb;
1985 tree last_conflicts_xz, last_conflicts_yz, last_conflicts_xyz;
1987 step_x = int_cst_value (CHREC_RIGHT (CHREC_LEFT (chrec_a)));
1988 step_y = int_cst_value (CHREC_RIGHT (chrec_a));
1989 step_z = int_cst_value (CHREC_RIGHT (chrec_b));
1992 estimated_loop_iterations_int (get_chrec_loop (CHREC_LEFT (chrec_a)),
1994 niter_y = estimated_loop_iterations_int (get_chrec_loop (chrec_a), false);
1995 niter_z = estimated_loop_iterations_int (get_chrec_loop (chrec_b), false);
1997 if (niter_x < 0 || niter_y < 0 || niter_z < 0)
1999 if (dump_file && (dump_flags & TDF_DETAILS))
2000 fprintf (dump_file, "overlap steps test failed: no iteration counts.\n");
2002 *overlaps_a = conflict_fn_not_known ();
2003 *overlaps_b = conflict_fn_not_known ();
2004 *last_conflicts = chrec_dont_know;
2008 niter = MIN (niter_x, niter_z);
2009 compute_overlap_steps_for_affine_univar (niter, step_x, step_z,
2012 &last_conflicts_xz, 1);
2013 niter = MIN (niter_y, niter_z);
2014 compute_overlap_steps_for_affine_univar (niter, step_y, step_z,
2017 &last_conflicts_yz, 2);
2018 niter = MIN (niter_x, niter_z);
2019 niter = MIN (niter_y, niter);
2020 compute_overlap_steps_for_affine_univar (niter, step_x + step_y, step_z,
2023 &last_conflicts_xyz, 3);
2025 xz_p = !integer_zerop (last_conflicts_xz);
2026 yz_p = !integer_zerop (last_conflicts_yz);
2027 xyz_p = !integer_zerop (last_conflicts_xyz);
2029 if (xz_p || yz_p || xyz_p)
2031 ova1 = affine_fn_cst (integer_zero_node);
2032 ova2 = affine_fn_cst (integer_zero_node);
2033 ovb = affine_fn_cst (integer_zero_node);
2036 affine_fn t0 = ova1;
2039 ova1 = affine_fn_plus (ova1, overlaps_a_xz);
2040 ovb = affine_fn_plus (ovb, overlaps_b_xz);
2041 affine_fn_free (t0);
2042 affine_fn_free (t2);
2043 *last_conflicts = last_conflicts_xz;
2047 affine_fn t0 = ova2;
2050 ova2 = affine_fn_plus (ova2, overlaps_a_yz);
2051 ovb = affine_fn_plus (ovb, overlaps_b_yz);
2052 affine_fn_free (t0);
2053 affine_fn_free (t2);
2054 *last_conflicts = last_conflicts_yz;
2058 affine_fn t0 = ova1;
2059 affine_fn t2 = ova2;
2062 ova1 = affine_fn_plus (ova1, overlaps_a_xyz);
2063 ova2 = affine_fn_plus (ova2, overlaps_a_xyz);
2064 ovb = affine_fn_plus (ovb, overlaps_b_xyz);
2065 affine_fn_free (t0);
2066 affine_fn_free (t2);
2067 affine_fn_free (t4);
2068 *last_conflicts = last_conflicts_xyz;
2070 *overlaps_a = conflict_fn (2, ova1, ova2);
2071 *overlaps_b = conflict_fn (1, ovb);
2075 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2076 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2077 *last_conflicts = integer_zero_node;
2080 affine_fn_free (overlaps_a_xz);
2081 affine_fn_free (overlaps_b_xz);
2082 affine_fn_free (overlaps_a_yz);
2083 affine_fn_free (overlaps_b_yz);
2084 affine_fn_free (overlaps_a_xyz);
2085 affine_fn_free (overlaps_b_xyz);
2088 /* Determines the overlapping elements due to accesses CHREC_A and
2089 CHREC_B, that are affine functions. This function cannot handle
2090 symbolic evolution functions, ie. when initial conditions are
2091 parameters, because it uses lambda matrices of integers. */
2094 analyze_subscript_affine_affine (tree chrec_a,
2096 conflict_function **overlaps_a,
2097 conflict_function **overlaps_b,
2098 tree *last_conflicts)
2100 unsigned nb_vars_a, nb_vars_b, dim;
2101 HOST_WIDE_INT init_a, init_b, gamma, gcd_alpha_beta;
2102 lambda_matrix A, U, S;
2104 if (eq_evolutions_p (chrec_a, chrec_b))
2106 /* The accessed index overlaps for each iteration in the
2108 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2109 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2110 *last_conflicts = chrec_dont_know;
2113 if (dump_file && (dump_flags & TDF_DETAILS))
2114 fprintf (dump_file, "(analyze_subscript_affine_affine \n");
2116 /* For determining the initial intersection, we have to solve a
2117 Diophantine equation. This is the most time consuming part.
2119 For answering to the question: "Is there a dependence?" we have
2120 to prove that there exists a solution to the Diophantine
2121 equation, and that the solution is in the iteration domain,
2122 i.e. the solution is positive or zero, and that the solution
2123 happens before the upper bound loop.nb_iterations. Otherwise
2124 there is no dependence. This function outputs a description of
2125 the iterations that hold the intersections. */
2127 nb_vars_a = nb_vars_in_chrec (chrec_a);
2128 nb_vars_b = nb_vars_in_chrec (chrec_b);
2130 dim = nb_vars_a + nb_vars_b;
2131 U = lambda_matrix_new (dim, dim);
2132 A = lambda_matrix_new (dim, 1);
2133 S = lambda_matrix_new (dim, 1);
2135 init_a = int_cst_value (initialize_matrix_A (A, chrec_a, 0, 1));
2136 init_b = int_cst_value (initialize_matrix_A (A, chrec_b, nb_vars_a, -1));
2137 gamma = init_b - init_a;
2139 /* Don't do all the hard work of solving the Diophantine equation
2140 when we already know the solution: for example,
2143 | gamma = 3 - 3 = 0.
2144 Then the first overlap occurs during the first iterations:
2145 | {3, +, 1}_1 ({0, +, 4}_x) = {3, +, 4}_2 ({0, +, 1}_x)
2149 if (nb_vars_a == 1 && nb_vars_b == 1)
2151 HOST_WIDE_INT step_a, step_b;
2152 HOST_WIDE_INT niter, niter_a, niter_b;
2155 niter_a = estimated_loop_iterations_int (get_chrec_loop (chrec_a),
2157 niter_b = estimated_loop_iterations_int (get_chrec_loop (chrec_b),
2159 niter = MIN (niter_a, niter_b);
2160 step_a = int_cst_value (CHREC_RIGHT (chrec_a));
2161 step_b = int_cst_value (CHREC_RIGHT (chrec_b));
2163 compute_overlap_steps_for_affine_univar (niter, step_a, step_b,
2166 *overlaps_a = conflict_fn (1, ova);
2167 *overlaps_b = conflict_fn (1, ovb);
2170 else if (nb_vars_a == 2 && nb_vars_b == 1)
2171 compute_overlap_steps_for_affine_1_2
2172 (chrec_a, chrec_b, overlaps_a, overlaps_b, last_conflicts);
2174 else if (nb_vars_a == 1 && nb_vars_b == 2)
2175 compute_overlap_steps_for_affine_1_2
2176 (chrec_b, chrec_a, overlaps_b, overlaps_a, last_conflicts);
2180 if (dump_file && (dump_flags & TDF_DETAILS))
2181 fprintf (dump_file, "affine-affine test failed: too many variables.\n");
2182 *overlaps_a = conflict_fn_not_known ();
2183 *overlaps_b = conflict_fn_not_known ();
2184 *last_conflicts = chrec_dont_know;
2186 goto end_analyze_subs_aa;
2190 lambda_matrix_right_hermite (A, dim, 1, S, U);
2195 lambda_matrix_row_negate (U, dim, 0);
2197 gcd_alpha_beta = S[0][0];
2199 /* Something went wrong: for example in {1, +, 0}_5 vs. {0, +, 0}_5,
2200 but that is a quite strange case. Instead of ICEing, answer
2202 if (gcd_alpha_beta == 0)
2204 *overlaps_a = conflict_fn_not_known ();
2205 *overlaps_b = conflict_fn_not_known ();
2206 *last_conflicts = chrec_dont_know;
2207 goto end_analyze_subs_aa;
2210 /* The classic "gcd-test". */
2211 if (!int_divides_p (gcd_alpha_beta, gamma))
2213 /* The "gcd-test" has determined that there is no integer
2214 solution, i.e. there is no dependence. */
2215 *overlaps_a = conflict_fn_no_dependence ();
2216 *overlaps_b = conflict_fn_no_dependence ();
2217 *last_conflicts = integer_zero_node;
2220 /* Both access functions are univariate. This includes SIV and MIV cases. */
2221 else if (nb_vars_a == 1 && nb_vars_b == 1)
2223 /* Both functions should have the same evolution sign. */
2224 if (((A[0][0] > 0 && -A[1][0] > 0)
2225 || (A[0][0] < 0 && -A[1][0] < 0)))
2227 /* The solutions are given by:
2229 | [GAMMA/GCD_ALPHA_BETA t].[u11 u12] = [x0]
2232 For a given integer t. Using the following variables,
2234 | i0 = u11 * gamma / gcd_alpha_beta
2235 | j0 = u12 * gamma / gcd_alpha_beta
2242 | y0 = j0 + j1 * t. */
2243 HOST_WIDE_INT i0, j0, i1, j1;
2245 i0 = U[0][0] * gamma / gcd_alpha_beta;
2246 j0 = U[0][1] * gamma / gcd_alpha_beta;
2250 if ((i1 == 0 && i0 < 0)
2251 || (j1 == 0 && j0 < 0))
2253 /* There is no solution.
2254 FIXME: The case "i0 > nb_iterations, j0 > nb_iterations"
2255 falls in here, but for the moment we don't look at the
2256 upper bound of the iteration domain. */
2257 *overlaps_a = conflict_fn_no_dependence ();
2258 *overlaps_b = conflict_fn_no_dependence ();
2259 *last_conflicts = integer_zero_node;
2260 goto end_analyze_subs_aa;
2263 if (i1 > 0 && j1 > 0)
2265 HOST_WIDE_INT niter_a = estimated_loop_iterations_int
2266 (get_chrec_loop (chrec_a), false);
2267 HOST_WIDE_INT niter_b = estimated_loop_iterations_int
2268 (get_chrec_loop (chrec_b), false);
2269 HOST_WIDE_INT niter = MIN (niter_a, niter_b);
2271 /* (X0, Y0) is a solution of the Diophantine equation:
2272 "chrec_a (X0) = chrec_b (Y0)". */
2273 HOST_WIDE_INT tau1 = MAX (CEIL (-i0, i1),
2275 HOST_WIDE_INT x0 = i1 * tau1 + i0;
2276 HOST_WIDE_INT y0 = j1 * tau1 + j0;
2278 /* (X1, Y1) is the smallest positive solution of the eq
2279 "chrec_a (X1) = chrec_b (Y1)", i.e. this is where the
2280 first conflict occurs. */
2281 HOST_WIDE_INT min_multiple = MIN (x0 / i1, y0 / j1);
2282 HOST_WIDE_INT x1 = x0 - i1 * min_multiple;
2283 HOST_WIDE_INT y1 = y0 - j1 * min_multiple;
2287 HOST_WIDE_INT tau2 = MIN (FLOOR_DIV (niter - i0, i1),
2288 FLOOR_DIV (niter - j0, j1));
2289 HOST_WIDE_INT last_conflict = tau2 - (x1 - i0)/i1;
2291 /* If the overlap occurs outside of the bounds of the
2292 loop, there is no dependence. */
2293 if (x1 > niter || y1 > niter)
2295 *overlaps_a = conflict_fn_no_dependence ();
2296 *overlaps_b = conflict_fn_no_dependence ();
2297 *last_conflicts = integer_zero_node;
2298 goto end_analyze_subs_aa;
2301 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
2304 *last_conflicts = chrec_dont_know;
2308 affine_fn_univar (build_int_cst (NULL_TREE, x1),
2310 build_int_cst (NULL_TREE, i1)));
2313 affine_fn_univar (build_int_cst (NULL_TREE, y1),
2315 build_int_cst (NULL_TREE, j1)));
2319 /* FIXME: For the moment, the upper bound of the
2320 iteration domain for i and j is not checked. */
2321 if (dump_file && (dump_flags & TDF_DETAILS))
2322 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2323 *overlaps_a = conflict_fn_not_known ();
2324 *overlaps_b = conflict_fn_not_known ();
2325 *last_conflicts = chrec_dont_know;
2330 if (dump_file && (dump_flags & TDF_DETAILS))
2331 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2332 *overlaps_a = conflict_fn_not_known ();
2333 *overlaps_b = conflict_fn_not_known ();
2334 *last_conflicts = chrec_dont_know;
2339 if (dump_file && (dump_flags & TDF_DETAILS))
2340 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2341 *overlaps_a = conflict_fn_not_known ();
2342 *overlaps_b = conflict_fn_not_known ();
2343 *last_conflicts = chrec_dont_know;
2346 end_analyze_subs_aa:
2347 if (dump_file && (dump_flags & TDF_DETAILS))
2349 fprintf (dump_file, " (overlaps_a = ");
2350 dump_conflict_function (dump_file, *overlaps_a);
2351 fprintf (dump_file, ")\n (overlaps_b = ");
2352 dump_conflict_function (dump_file, *overlaps_b);
2353 fprintf (dump_file, ")\n");
2354 fprintf (dump_file, ")\n");
2358 /* Returns true when analyze_subscript_affine_affine can be used for
2359 determining the dependence relation between chrec_a and chrec_b,
2360 that contain symbols. This function modifies chrec_a and chrec_b
2361 such that the analysis result is the same, and such that they don't
2362 contain symbols, and then can safely be passed to the analyzer.
2364 Example: The analysis of the following tuples of evolutions produce
2365 the same results: {x+1, +, 1}_1 vs. {x+3, +, 1}_1, and {-2, +, 1}_1
2368 {x+1, +, 1}_1 ({2, +, 1}_1) = {x+3, +, 1}_1 ({0, +, 1}_1)
2369 {-2, +, 1}_1 ({2, +, 1}_1) = {0, +, 1}_1 ({0, +, 1}_1)
2373 can_use_analyze_subscript_affine_affine (tree *chrec_a, tree *chrec_b)
2375 tree diff, type, left_a, left_b, right_b;
2377 if (chrec_contains_symbols (CHREC_RIGHT (*chrec_a))
2378 || chrec_contains_symbols (CHREC_RIGHT (*chrec_b)))
2379 /* FIXME: For the moment not handled. Might be refined later. */
2382 type = chrec_type (*chrec_a);
2383 left_a = CHREC_LEFT (*chrec_a);
2384 left_b = chrec_convert (type, CHREC_LEFT (*chrec_b), NULL);
2385 diff = chrec_fold_minus (type, left_a, left_b);
2387 if (!evolution_function_is_constant_p (diff))
2390 if (dump_file && (dump_flags & TDF_DETAILS))
2391 fprintf (dump_file, "can_use_subscript_aff_aff_for_symbolic \n");
2393 *chrec_a = build_polynomial_chrec (CHREC_VARIABLE (*chrec_a),
2394 diff, CHREC_RIGHT (*chrec_a));
2395 right_b = chrec_convert (type, CHREC_RIGHT (*chrec_b), NULL);
2396 *chrec_b = build_polynomial_chrec (CHREC_VARIABLE (*chrec_b),
2397 build_int_cst (type, 0),
2402 /* Analyze a SIV (Single Index Variable) subscript. *OVERLAPS_A and
2403 *OVERLAPS_B are initialized to the functions that describe the
2404 relation between the elements accessed twice by CHREC_A and
2405 CHREC_B. For k >= 0, the following property is verified:
2407 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2410 analyze_siv_subscript (tree chrec_a,
2412 conflict_function **overlaps_a,
2413 conflict_function **overlaps_b,
2414 tree *last_conflicts,
2417 dependence_stats.num_siv++;
2419 if (dump_file && (dump_flags & TDF_DETAILS))
2420 fprintf (dump_file, "(analyze_siv_subscript \n");
2422 if (evolution_function_is_constant_p (chrec_a)
2423 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2424 analyze_siv_subscript_cst_affine (chrec_a, chrec_b,
2425 overlaps_a, overlaps_b, last_conflicts);
2427 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2428 && evolution_function_is_constant_p (chrec_b))
2429 analyze_siv_subscript_cst_affine (chrec_b, chrec_a,
2430 overlaps_b, overlaps_a, last_conflicts);
2432 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2433 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2435 if (!chrec_contains_symbols (chrec_a)
2436 && !chrec_contains_symbols (chrec_b))
2438 analyze_subscript_affine_affine (chrec_a, chrec_b,
2439 overlaps_a, overlaps_b,
2442 if (CF_NOT_KNOWN_P (*overlaps_a)
2443 || CF_NOT_KNOWN_P (*overlaps_b))
2444 dependence_stats.num_siv_unimplemented++;
2445 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2446 || CF_NO_DEPENDENCE_P (*overlaps_b))
2447 dependence_stats.num_siv_independent++;
2449 dependence_stats.num_siv_dependent++;
2451 else if (can_use_analyze_subscript_affine_affine (&chrec_a,
2454 analyze_subscript_affine_affine (chrec_a, chrec_b,
2455 overlaps_a, overlaps_b,
2458 if (CF_NOT_KNOWN_P (*overlaps_a)
2459 || CF_NOT_KNOWN_P (*overlaps_b))
2460 dependence_stats.num_siv_unimplemented++;
2461 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2462 || CF_NO_DEPENDENCE_P (*overlaps_b))
2463 dependence_stats.num_siv_independent++;
2465 dependence_stats.num_siv_dependent++;
2468 goto siv_subscript_dontknow;
2473 siv_subscript_dontknow:;
2474 if (dump_file && (dump_flags & TDF_DETAILS))
2475 fprintf (dump_file, "siv test failed: unimplemented.\n");
2476 *overlaps_a = conflict_fn_not_known ();
2477 *overlaps_b = conflict_fn_not_known ();
2478 *last_conflicts = chrec_dont_know;
2479 dependence_stats.num_siv_unimplemented++;
2482 if (dump_file && (dump_flags & TDF_DETAILS))
2483 fprintf (dump_file, ")\n");
2486 /* Returns false if we can prove that the greatest common divisor of the steps
2487 of CHREC does not divide CST, false otherwise. */
2490 gcd_of_steps_may_divide_p (const_tree chrec, const_tree cst)
2492 HOST_WIDE_INT cd = 0, val;
2495 if (!host_integerp (cst, 0))
2497 val = tree_low_cst (cst, 0);
2499 while (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
2501 step = CHREC_RIGHT (chrec);
2502 if (!host_integerp (step, 0))
2504 cd = gcd (cd, tree_low_cst (step, 0));
2505 chrec = CHREC_LEFT (chrec);
2508 return val % cd == 0;
2511 /* Analyze a MIV (Multiple Index Variable) subscript with respect to
2512 LOOP_NEST. *OVERLAPS_A and *OVERLAPS_B are initialized to the
2513 functions that describe the relation between the elements accessed
2514 twice by CHREC_A and CHREC_B. For k >= 0, the following property
2517 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2520 analyze_miv_subscript (tree chrec_a,
2522 conflict_function **overlaps_a,
2523 conflict_function **overlaps_b,
2524 tree *last_conflicts,
2525 struct loop *loop_nest)
2527 /* FIXME: This is a MIV subscript, not yet handled.
2528 Example: (A[{1, +, 1}_1] vs. A[{1, +, 1}_2]) that comes from
2531 In the SIV test we had to solve a Diophantine equation with two
2532 variables. In the MIV case we have to solve a Diophantine
2533 equation with 2*n variables (if the subscript uses n IVs).
2535 tree type, difference;
2537 dependence_stats.num_miv++;
2538 if (dump_file && (dump_flags & TDF_DETAILS))
2539 fprintf (dump_file, "(analyze_miv_subscript \n");
2541 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
2542 chrec_a = chrec_convert (type, chrec_a, NULL);
2543 chrec_b = chrec_convert (type, chrec_b, NULL);
2544 difference = chrec_fold_minus (type, chrec_a, chrec_b);
2546 if (eq_evolutions_p (chrec_a, chrec_b))
2548 /* Access functions are the same: all the elements are accessed
2549 in the same order. */
2550 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2551 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2552 *last_conflicts = estimated_loop_iterations_tree
2553 (get_chrec_loop (chrec_a), true);
2554 dependence_stats.num_miv_dependent++;
2557 else if (evolution_function_is_constant_p (difference)
2558 /* For the moment, the following is verified:
2559 evolution_function_is_affine_multivariate_p (chrec_a,
2561 && !gcd_of_steps_may_divide_p (chrec_a, difference))
2563 /* testsuite/.../ssa-chrec-33.c
2564 {{21, +, 2}_1, +, -2}_2 vs. {{20, +, 2}_1, +, -2}_2
2566 The difference is 1, and all the evolution steps are multiples
2567 of 2, consequently there are no overlapping elements. */
2568 *overlaps_a = conflict_fn_no_dependence ();
2569 *overlaps_b = conflict_fn_no_dependence ();
2570 *last_conflicts = integer_zero_node;
2571 dependence_stats.num_miv_independent++;
2574 else if (evolution_function_is_affine_multivariate_p (chrec_a, loop_nest->num)
2575 && !chrec_contains_symbols (chrec_a)
2576 && evolution_function_is_affine_multivariate_p (chrec_b, loop_nest->num)
2577 && !chrec_contains_symbols (chrec_b))
2579 /* testsuite/.../ssa-chrec-35.c
2580 {0, +, 1}_2 vs. {0, +, 1}_3
2581 the overlapping elements are respectively located at iterations:
2582 {0, +, 1}_x and {0, +, 1}_x,
2583 in other words, we have the equality:
2584 {0, +, 1}_2 ({0, +, 1}_x) = {0, +, 1}_3 ({0, +, 1}_x)
2587 {{0, +, 1}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y) =
2588 {0, +, 1}_1 ({{0, +, 1}_x, +, 2}_y)
2590 {{0, +, 2}_1, +, 3}_2 ({0, +, 1}_y, {0, +, 1}_x) =
2591 {{0, +, 3}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y)
2593 analyze_subscript_affine_affine (chrec_a, chrec_b,
2594 overlaps_a, overlaps_b, last_conflicts);
2596 if (CF_NOT_KNOWN_P (*overlaps_a)
2597 || CF_NOT_KNOWN_P (*overlaps_b))
2598 dependence_stats.num_miv_unimplemented++;
2599 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2600 || CF_NO_DEPENDENCE_P (*overlaps_b))
2601 dependence_stats.num_miv_independent++;
2603 dependence_stats.num_miv_dependent++;
2608 /* When the analysis is too difficult, answer "don't know". */
2609 if (dump_file && (dump_flags & TDF_DETAILS))
2610 fprintf (dump_file, "analyze_miv_subscript test failed: unimplemented.\n");
2612 *overlaps_a = conflict_fn_not_known ();
2613 *overlaps_b = conflict_fn_not_known ();
2614 *last_conflicts = chrec_dont_know;
2615 dependence_stats.num_miv_unimplemented++;
2618 if (dump_file && (dump_flags & TDF_DETAILS))
2619 fprintf (dump_file, ")\n");
2622 /* Determines the iterations for which CHREC_A is equal to CHREC_B in
2623 with respect to LOOP_NEST. OVERLAP_ITERATIONS_A and
2624 OVERLAP_ITERATIONS_B are initialized with two functions that
2625 describe the iterations that contain conflicting elements.
2627 Remark: For an integer k >= 0, the following equality is true:
2629 CHREC_A (OVERLAP_ITERATIONS_A (k)) == CHREC_B (OVERLAP_ITERATIONS_B (k)).
2633 analyze_overlapping_iterations (tree chrec_a,
2635 conflict_function **overlap_iterations_a,
2636 conflict_function **overlap_iterations_b,
2637 tree *last_conflicts, struct loop *loop_nest)
2639 unsigned int lnn = loop_nest->num;
2641 dependence_stats.num_subscript_tests++;
2643 if (dump_file && (dump_flags & TDF_DETAILS))
2645 fprintf (dump_file, "(analyze_overlapping_iterations \n");
2646 fprintf (dump_file, " (chrec_a = ");
2647 print_generic_expr (dump_file, chrec_a, 0);
2648 fprintf (dump_file, ")\n (chrec_b = ");
2649 print_generic_expr (dump_file, chrec_b, 0);
2650 fprintf (dump_file, ")\n");
2653 if (chrec_a == NULL_TREE
2654 || chrec_b == NULL_TREE
2655 || chrec_contains_undetermined (chrec_a)
2656 || chrec_contains_undetermined (chrec_b))
2658 dependence_stats.num_subscript_undetermined++;
2660 *overlap_iterations_a = conflict_fn_not_known ();
2661 *overlap_iterations_b = conflict_fn_not_known ();
2664 /* If they are the same chrec, and are affine, they overlap
2665 on every iteration. */
2666 else if (eq_evolutions_p (chrec_a, chrec_b)
2667 && evolution_function_is_affine_multivariate_p (chrec_a, lnn))
2669 dependence_stats.num_same_subscript_function++;
2670 *overlap_iterations_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2671 *overlap_iterations_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2672 *last_conflicts = chrec_dont_know;
2675 /* If they aren't the same, and aren't affine, we can't do anything
2677 else if ((chrec_contains_symbols (chrec_a)
2678 || chrec_contains_symbols (chrec_b))
2679 && (!evolution_function_is_affine_multivariate_p (chrec_a, lnn)
2680 || !evolution_function_is_affine_multivariate_p (chrec_b, lnn)))
2682 dependence_stats.num_subscript_undetermined++;
2683 *overlap_iterations_a = conflict_fn_not_known ();
2684 *overlap_iterations_b = conflict_fn_not_known ();
2687 else if (ziv_subscript_p (chrec_a, chrec_b))
2688 analyze_ziv_subscript (chrec_a, chrec_b,
2689 overlap_iterations_a, overlap_iterations_b,
2692 else if (siv_subscript_p (chrec_a, chrec_b))
2693 analyze_siv_subscript (chrec_a, chrec_b,
2694 overlap_iterations_a, overlap_iterations_b,
2695 last_conflicts, lnn);
2698 analyze_miv_subscript (chrec_a, chrec_b,
2699 overlap_iterations_a, overlap_iterations_b,
2700 last_conflicts, loop_nest);
2702 if (dump_file && (dump_flags & TDF_DETAILS))
2704 fprintf (dump_file, " (overlap_iterations_a = ");
2705 dump_conflict_function (dump_file, *overlap_iterations_a);
2706 fprintf (dump_file, ")\n (overlap_iterations_b = ");
2707 dump_conflict_function (dump_file, *overlap_iterations_b);
2708 fprintf (dump_file, ")\n");
2709 fprintf (dump_file, ")\n");
2713 /* Helper function for uniquely inserting distance vectors. */
2716 save_dist_v (struct data_dependence_relation *ddr, lambda_vector dist_v)
2721 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, v); i++)
2722 if (lambda_vector_equal (v, dist_v, DDR_NB_LOOPS (ddr)))
2725 VEC_safe_push (lambda_vector, heap, DDR_DIST_VECTS (ddr), dist_v);
2728 /* Helper function for uniquely inserting direction vectors. */
2731 save_dir_v (struct data_dependence_relation *ddr, lambda_vector dir_v)
2736 for (i = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), i, v); i++)
2737 if (lambda_vector_equal (v, dir_v, DDR_NB_LOOPS (ddr)))
2740 VEC_safe_push (lambda_vector, heap, DDR_DIR_VECTS (ddr), dir_v);
2743 /* Add a distance of 1 on all the loops outer than INDEX. If we
2744 haven't yet determined a distance for this outer loop, push a new
2745 distance vector composed of the previous distance, and a distance
2746 of 1 for this outer loop. Example:
2754 Saved vectors are of the form (dist_in_1, dist_in_2). First, we
2755 save (0, 1), then we have to save (1, 0). */
2758 add_outer_distances (struct data_dependence_relation *ddr,
2759 lambda_vector dist_v, int index)
2761 /* For each outer loop where init_v is not set, the accesses are
2762 in dependence of distance 1 in the loop. */
2763 while (--index >= 0)
2765 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2766 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
2768 save_dist_v (ddr, save_v);
2772 /* Return false when fail to represent the data dependence as a
2773 distance vector. INIT_B is set to true when a component has been
2774 added to the distance vector DIST_V. INDEX_CARRY is then set to
2775 the index in DIST_V that carries the dependence. */
2778 build_classic_dist_vector_1 (struct data_dependence_relation *ddr,
2779 struct data_reference *ddr_a,
2780 struct data_reference *ddr_b,
2781 lambda_vector dist_v, bool *init_b,
2785 lambda_vector init_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2787 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2789 tree access_fn_a, access_fn_b;
2790 struct subscript *subscript = DDR_SUBSCRIPT (ddr, i);
2792 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2794 non_affine_dependence_relation (ddr);
2798 access_fn_a = DR_ACCESS_FN (ddr_a, i);
2799 access_fn_b = DR_ACCESS_FN (ddr_b, i);
2801 if (TREE_CODE (access_fn_a) == POLYNOMIAL_CHREC
2802 && TREE_CODE (access_fn_b) == POLYNOMIAL_CHREC)
2805 int index_a = index_in_loop_nest (CHREC_VARIABLE (access_fn_a),
2806 DDR_LOOP_NEST (ddr));
2807 int index_b = index_in_loop_nest (CHREC_VARIABLE (access_fn_b),
2808 DDR_LOOP_NEST (ddr));
2810 /* The dependence is carried by the outermost loop. Example:
2817 In this case, the dependence is carried by loop_1. */
2818 index = index_a < index_b ? index_a : index_b;
2819 *index_carry = MIN (index, *index_carry);
2821 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2823 non_affine_dependence_relation (ddr);
2827 dist = int_cst_value (SUB_DISTANCE (subscript));
2829 /* This is the subscript coupling test. If we have already
2830 recorded a distance for this loop (a distance coming from
2831 another subscript), it should be the same. For example,
2832 in the following code, there is no dependence:
2839 if (init_v[index] != 0 && dist_v[index] != dist)
2841 finalize_ddr_dependent (ddr, chrec_known);
2845 dist_v[index] = dist;
2849 else if (!operand_equal_p (access_fn_a, access_fn_b, 0))
2851 /* This can be for example an affine vs. constant dependence
2852 (T[i] vs. T[3]) that is not an affine dependence and is
2853 not representable as a distance vector. */
2854 non_affine_dependence_relation (ddr);
2862 /* Return true when the DDR contains only constant access functions. */
2865 constant_access_functions (const struct data_dependence_relation *ddr)
2869 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2870 if (!evolution_function_is_constant_p (DR_ACCESS_FN (DDR_A (ddr), i))
2871 || !evolution_function_is_constant_p (DR_ACCESS_FN (DDR_B (ddr), i)))
2877 /* Helper function for the case where DDR_A and DDR_B are the same
2878 multivariate access function with a constant step. For an example
2882 add_multivariate_self_dist (struct data_dependence_relation *ddr, tree c_2)
2885 tree c_1 = CHREC_LEFT (c_2);
2886 tree c_0 = CHREC_LEFT (c_1);
2887 lambda_vector dist_v;
2890 /* Polynomials with more than 2 variables are not handled yet. When
2891 the evolution steps are parameters, it is not possible to
2892 represent the dependence using classical distance vectors. */
2893 if (TREE_CODE (c_0) != INTEGER_CST
2894 || TREE_CODE (CHREC_RIGHT (c_1)) != INTEGER_CST
2895 || TREE_CODE (CHREC_RIGHT (c_2)) != INTEGER_CST)
2897 DDR_AFFINE_P (ddr) = false;
2901 x_2 = index_in_loop_nest (CHREC_VARIABLE (c_2), DDR_LOOP_NEST (ddr));
2902 x_1 = index_in_loop_nest (CHREC_VARIABLE (c_1), DDR_LOOP_NEST (ddr));
2904 /* For "{{0, +, 2}_1, +, 3}_2" the distance vector is (3, -2). */
2905 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2906 v1 = int_cst_value (CHREC_RIGHT (c_1));
2907 v2 = int_cst_value (CHREC_RIGHT (c_2));
2920 save_dist_v (ddr, dist_v);
2922 add_outer_distances (ddr, dist_v, x_1);
2925 /* Helper function for the case where DDR_A and DDR_B are the same
2926 access functions. */
2929 add_other_self_distances (struct data_dependence_relation *ddr)
2931 lambda_vector dist_v;
2933 int index_carry = DDR_NB_LOOPS (ddr);
2935 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2937 tree access_fun = DR_ACCESS_FN (DDR_A (ddr), i);
2939 if (TREE_CODE (access_fun) == POLYNOMIAL_CHREC)
2941 if (!evolution_function_is_univariate_p (access_fun))
2943 if (DDR_NUM_SUBSCRIPTS (ddr) != 1)
2945 DDR_ARE_DEPENDENT (ddr) = chrec_dont_know;
2949 access_fun = DR_ACCESS_FN (DDR_A (ddr), 0);
2951 if (TREE_CODE (CHREC_LEFT (access_fun)) == POLYNOMIAL_CHREC)
2952 add_multivariate_self_dist (ddr, access_fun);
2954 /* The evolution step is not constant: it varies in
2955 the outer loop, so this cannot be represented by a
2956 distance vector. For example in pr34635.c the
2957 evolution is {0, +, {0, +, 4}_1}_2. */
2958 DDR_AFFINE_P (ddr) = false;
2963 index_carry = MIN (index_carry,
2964 index_in_loop_nest (CHREC_VARIABLE (access_fun),
2965 DDR_LOOP_NEST (ddr)));
2969 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2970 add_outer_distances (ddr, dist_v, index_carry);
2974 insert_innermost_unit_dist_vector (struct data_dependence_relation *ddr)
2976 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2978 dist_v[DDR_INNER_LOOP (ddr)] = 1;
2979 save_dist_v (ddr, dist_v);
2982 /* Adds a unit distance vector to DDR when there is a 0 overlap. This
2983 is the case for example when access functions are the same and
2984 equal to a constant, as in:
2991 in which case the distance vectors are (0) and (1). */
2994 add_distance_for_zero_overlaps (struct data_dependence_relation *ddr)
2998 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
3000 subscript_p sub = DDR_SUBSCRIPT (ddr, i);
3001 conflict_function *ca = SUB_CONFLICTS_IN_A (sub);
3002 conflict_function *cb = SUB_CONFLICTS_IN_B (sub);
3004 for (j = 0; j < ca->n; j++)
3005 if (affine_function_zero_p (ca->fns[j]))
3007 insert_innermost_unit_dist_vector (ddr);
3011 for (j = 0; j < cb->n; j++)
3012 if (affine_function_zero_p (cb->fns[j]))
3014 insert_innermost_unit_dist_vector (ddr);
3020 /* Compute the classic per loop distance vector. DDR is the data
3021 dependence relation to build a vector from. Return false when fail
3022 to represent the data dependence as a distance vector. */
3025 build_classic_dist_vector (struct data_dependence_relation *ddr,
3026 struct loop *loop_nest)
3028 bool init_b = false;
3029 int index_carry = DDR_NB_LOOPS (ddr);
3030 lambda_vector dist_v;
3032 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3035 if (same_access_functions (ddr))
3037 /* Save the 0 vector. */
3038 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3039 save_dist_v (ddr, dist_v);
3041 if (constant_access_functions (ddr))
3042 add_distance_for_zero_overlaps (ddr);
3044 if (DDR_NB_LOOPS (ddr) > 1)
3045 add_other_self_distances (ddr);
3050 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3051 if (!build_classic_dist_vector_1 (ddr, DDR_A (ddr), DDR_B (ddr),
3052 dist_v, &init_b, &index_carry))
3055 /* Save the distance vector if we initialized one. */
3058 /* Verify a basic constraint: classic distance vectors should
3059 always be lexicographically positive.
3061 Data references are collected in the order of execution of
3062 the program, thus for the following loop
3064 | for (i = 1; i < 100; i++)
3065 | for (j = 1; j < 100; j++)
3067 | t = T[j+1][i-1]; // A
3068 | T[j][i] = t + 2; // B
3071 references are collected following the direction of the wind:
3072 A then B. The data dependence tests are performed also
3073 following this order, such that we're looking at the distance
3074 separating the elements accessed by A from the elements later
3075 accessed by B. But in this example, the distance returned by
3076 test_dep (A, B) is lexicographically negative (-1, 1), that
3077 means that the access A occurs later than B with respect to
3078 the outer loop, ie. we're actually looking upwind. In this
3079 case we solve test_dep (B, A) looking downwind to the
3080 lexicographically positive solution, that returns the
3081 distance vector (1, -1). */
3082 if (!lambda_vector_lexico_pos (dist_v, DDR_NB_LOOPS (ddr)))
3084 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3085 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3088 compute_subscript_distance (ddr);
3089 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3090 save_v, &init_b, &index_carry))
3092 save_dist_v (ddr, save_v);
3093 DDR_REVERSED_P (ddr) = true;
3095 /* In this case there is a dependence forward for all the
3098 | for (k = 1; k < 100; k++)
3099 | for (i = 1; i < 100; i++)
3100 | for (j = 1; j < 100; j++)
3102 | t = T[j+1][i-1]; // A
3103 | T[j][i] = t + 2; // B
3111 if (DDR_NB_LOOPS (ddr) > 1)
3113 add_outer_distances (ddr, save_v, index_carry);
3114 add_outer_distances (ddr, dist_v, index_carry);
3119 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3120 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
3122 if (DDR_NB_LOOPS (ddr) > 1)
3124 lambda_vector opposite_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3126 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr),
3127 DDR_A (ddr), loop_nest))
3129 compute_subscript_distance (ddr);
3130 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3131 opposite_v, &init_b,
3135 save_dist_v (ddr, save_v);
3136 add_outer_distances (ddr, dist_v, index_carry);
3137 add_outer_distances (ddr, opposite_v, index_carry);
3140 save_dist_v (ddr, save_v);
3145 /* There is a distance of 1 on all the outer loops: Example:
3146 there is a dependence of distance 1 on loop_1 for the array A.
3152 add_outer_distances (ddr, dist_v,
3153 lambda_vector_first_nz (dist_v,
3154 DDR_NB_LOOPS (ddr), 0));
3157 if (dump_file && (dump_flags & TDF_DETAILS))
3161 fprintf (dump_file, "(build_classic_dist_vector\n");
3162 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3164 fprintf (dump_file, " dist_vector = (");
3165 print_lambda_vector (dump_file, DDR_DIST_VECT (ddr, i),
3166 DDR_NB_LOOPS (ddr));
3167 fprintf (dump_file, " )\n");
3169 fprintf (dump_file, ")\n");
3175 /* Return the direction for a given distance.
3176 FIXME: Computing dir this way is suboptimal, since dir can catch
3177 cases that dist is unable to represent. */
3179 static inline enum data_dependence_direction
3180 dir_from_dist (int dist)
3183 return dir_positive;
3185 return dir_negative;
3190 /* Compute the classic per loop direction vector. DDR is the data
3191 dependence relation to build a vector from. */
3194 build_classic_dir_vector (struct data_dependence_relation *ddr)
3197 lambda_vector dist_v;
3199 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v); i++)
3201 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3203 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3204 dir_v[j] = dir_from_dist (dist_v[j]);
3206 save_dir_v (ddr, dir_v);
3210 /* Helper function. Returns true when there is a dependence between
3211 data references DRA and DRB. */
3214 subscript_dependence_tester_1 (struct data_dependence_relation *ddr,
3215 struct data_reference *dra,
3216 struct data_reference *drb,
3217 struct loop *loop_nest)
3220 tree last_conflicts;
3221 struct subscript *subscript;
3223 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3226 conflict_function *overlaps_a, *overlaps_b;
3228 analyze_overlapping_iterations (DR_ACCESS_FN (dra, i),
3229 DR_ACCESS_FN (drb, i),
3230 &overlaps_a, &overlaps_b,
3231 &last_conflicts, loop_nest);
3233 if (CF_NOT_KNOWN_P (overlaps_a)
3234 || CF_NOT_KNOWN_P (overlaps_b))
3236 finalize_ddr_dependent (ddr, chrec_dont_know);
3237 dependence_stats.num_dependence_undetermined++;
3238 free_conflict_function (overlaps_a);
3239 free_conflict_function (overlaps_b);
3243 else if (CF_NO_DEPENDENCE_P (overlaps_a)
3244 || CF_NO_DEPENDENCE_P (overlaps_b))
3246 finalize_ddr_dependent (ddr, chrec_known);
3247 dependence_stats.num_dependence_independent++;
3248 free_conflict_function (overlaps_a);
3249 free_conflict_function (overlaps_b);
3255 if (SUB_CONFLICTS_IN_A (subscript))
3256 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3257 if (SUB_CONFLICTS_IN_B (subscript))
3258 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3260 SUB_CONFLICTS_IN_A (subscript) = overlaps_a;
3261 SUB_CONFLICTS_IN_B (subscript) = overlaps_b;
3262 SUB_LAST_CONFLICT (subscript) = last_conflicts;
3269 /* Computes the conflicting iterations in LOOP_NEST, and initialize DDR. */
3272 subscript_dependence_tester (struct data_dependence_relation *ddr,
3273 struct loop *loop_nest)
3276 if (dump_file && (dump_flags & TDF_DETAILS))
3277 fprintf (dump_file, "(subscript_dependence_tester \n");
3279 if (subscript_dependence_tester_1 (ddr, DDR_A (ddr), DDR_B (ddr), loop_nest))
3280 dependence_stats.num_dependence_dependent++;
3282 compute_subscript_distance (ddr);
3283 if (build_classic_dist_vector (ddr, loop_nest))
3284 build_classic_dir_vector (ddr);
3286 if (dump_file && (dump_flags & TDF_DETAILS))
3287 fprintf (dump_file, ")\n");
3290 /* Returns true when all the access functions of A are affine or
3291 constant with respect to LOOP_NEST. */
3294 access_functions_are_affine_or_constant_p (const struct data_reference *a,
3295 const struct loop *loop_nest)
3298 VEC(tree,heap) *fns = DR_ACCESS_FNS (a);
3301 for (i = 0; VEC_iterate (tree, fns, i, t); i++)
3302 if (!evolution_function_is_invariant_p (t, loop_nest->num)
3303 && !evolution_function_is_affine_multivariate_p (t, loop_nest->num))
3309 /* Return true if we can create an affine data-ref for OP in STMT. */
3312 stmt_simple_memref_p (struct loop *loop, gimple stmt, tree op)
3314 data_reference_p dr;
3317 dr = create_data_ref (loop, op, stmt, true);
3318 if (!access_functions_are_affine_or_constant_p (dr, loop))
3325 /* Initializes an equation for an OMEGA problem using the information
3326 contained in the ACCESS_FUN. Returns true when the operation
3329 PB is the omega constraint system.
3330 EQ is the number of the equation to be initialized.
3331 OFFSET is used for shifting the variables names in the constraints:
3332 a constrain is composed of 2 * the number of variables surrounding
3333 dependence accesses. OFFSET is set either to 0 for the first n variables,
3334 then it is set to n.
3335 ACCESS_FUN is expected to be an affine chrec. */
3338 init_omega_eq_with_af (omega_pb pb, unsigned eq,
3339 unsigned int offset, tree access_fun,
3340 struct data_dependence_relation *ddr)
3342 switch (TREE_CODE (access_fun))
3344 case POLYNOMIAL_CHREC:
3346 tree left = CHREC_LEFT (access_fun);
3347 tree right = CHREC_RIGHT (access_fun);
3348 int var = CHREC_VARIABLE (access_fun);
3351 if (TREE_CODE (right) != INTEGER_CST)
3354 var_idx = index_in_loop_nest (var, DDR_LOOP_NEST (ddr));
3355 pb->eqs[eq].coef[offset + var_idx + 1] = int_cst_value (right);
3357 /* Compute the innermost loop index. */
3358 DDR_INNER_LOOP (ddr) = MAX (DDR_INNER_LOOP (ddr), var_idx);
3361 pb->eqs[eq].coef[var_idx + DDR_NB_LOOPS (ddr) + 1]
3362 += int_cst_value (right);
3364 switch (TREE_CODE (left))
3366 case POLYNOMIAL_CHREC:
3367 return init_omega_eq_with_af (pb, eq, offset, left, ddr);
3370 pb->eqs[eq].coef[0] += int_cst_value (left);
3379 pb->eqs[eq].coef[0] += int_cst_value (access_fun);
3387 /* As explained in the comments preceding init_omega_for_ddr, we have
3388 to set up a system for each loop level, setting outer loops
3389 variation to zero, and current loop variation to positive or zero.
3390 Save each lexico positive distance vector. */
3393 omega_extract_distance_vectors (omega_pb pb,
3394 struct data_dependence_relation *ddr)
3398 struct loop *loopi, *loopj;
3399 enum omega_result res;
3401 /* Set a new problem for each loop in the nest. The basis is the
3402 problem that we have initialized until now. On top of this we
3403 add new constraints. */
3404 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3405 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3408 omega_pb copy = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr),
3409 DDR_NB_LOOPS (ddr));
3411 omega_copy_problem (copy, pb);
3413 /* For all the outer loops "loop_j", add "dj = 0". */
3415 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3417 eq = omega_add_zero_eq (copy, omega_black);
3418 copy->eqs[eq].coef[j + 1] = 1;
3421 /* For "loop_i", add "0 <= di". */
3422 geq = omega_add_zero_geq (copy, omega_black);
3423 copy->geqs[geq].coef[i + 1] = 1;
3425 /* Reduce the constraint system, and test that the current
3426 problem is feasible. */
3427 res = omega_simplify_problem (copy);
3428 if (res == omega_false
3429 || res == omega_unknown
3430 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3433 for (eq = 0; eq < copy->num_subs; eq++)
3434 if (copy->subs[eq].key == (int) i + 1)
3436 dist = copy->subs[eq].coef[0];
3442 /* Reinitialize problem... */
3443 omega_copy_problem (copy, pb);
3445 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3447 eq = omega_add_zero_eq (copy, omega_black);
3448 copy->eqs[eq].coef[j + 1] = 1;
3451 /* ..., but this time "di = 1". */
3452 eq = omega_add_zero_eq (copy, omega_black);
3453 copy->eqs[eq].coef[i + 1] = 1;
3454 copy->eqs[eq].coef[0] = -1;
3456 res = omega_simplify_problem (copy);
3457 if (res == omega_false
3458 || res == omega_unknown
3459 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3462 for (eq = 0; eq < copy->num_subs; eq++)
3463 if (copy->subs[eq].key == (int) i + 1)
3465 dist = copy->subs[eq].coef[0];
3471 /* Save the lexicographically positive distance vector. */
3474 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3475 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3479 for (eq = 0; eq < copy->num_subs; eq++)
3480 if (copy->subs[eq].key > 0)
3482 dist = copy->subs[eq].coef[0];
3483 dist_v[copy->subs[eq].key - 1] = dist;
3486 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3487 dir_v[j] = dir_from_dist (dist_v[j]);
3489 save_dist_v (ddr, dist_v);
3490 save_dir_v (ddr, dir_v);
3494 omega_free_problem (copy);
3498 /* This is called for each subscript of a tuple of data references:
3499 insert an equality for representing the conflicts. */
3502 omega_setup_subscript (tree access_fun_a, tree access_fun_b,
3503 struct data_dependence_relation *ddr,
3504 omega_pb pb, bool *maybe_dependent)
3507 tree type = signed_type_for_types (TREE_TYPE (access_fun_a),
3508 TREE_TYPE (access_fun_b));
3509 tree fun_a = chrec_convert (type, access_fun_a, NULL);
3510 tree fun_b = chrec_convert (type, access_fun_b, NULL);
3511 tree difference = chrec_fold_minus (type, fun_a, fun_b);
3513 /* When the fun_a - fun_b is not constant, the dependence is not
3514 captured by the classic distance vector representation. */
3515 if (TREE_CODE (difference) != INTEGER_CST)
3519 if (ziv_subscript_p (fun_a, fun_b) && !integer_zerop (difference))
3521 /* There is no dependence. */
3522 *maybe_dependent = false;
3526 fun_b = chrec_fold_multiply (type, fun_b, integer_minus_one_node);
3528 eq = omega_add_zero_eq (pb, omega_black);
3529 if (!init_omega_eq_with_af (pb, eq, DDR_NB_LOOPS (ddr), fun_a, ddr)
3530 || !init_omega_eq_with_af (pb, eq, 0, fun_b, ddr))
3531 /* There is probably a dependence, but the system of
3532 constraints cannot be built: answer "don't know". */
3536 if (DDR_NB_LOOPS (ddr) != 0 && pb->eqs[eq].coef[0]
3537 && !int_divides_p (lambda_vector_gcd
3538 ((lambda_vector) &(pb->eqs[eq].coef[1]),
3539 2 * DDR_NB_LOOPS (ddr)),
3540 pb->eqs[eq].coef[0]))
3542 /* There is no dependence. */
3543 *maybe_dependent = false;
3550 /* Helper function, same as init_omega_for_ddr but specialized for
3551 data references A and B. */
3554 init_omega_for_ddr_1 (struct data_reference *dra, struct data_reference *drb,
3555 struct data_dependence_relation *ddr,
3556 omega_pb pb, bool *maybe_dependent)
3561 unsigned nb_loops = DDR_NB_LOOPS (ddr);
3563 /* Insert an equality per subscript. */
3564 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
3566 if (!omega_setup_subscript (DR_ACCESS_FN (dra, i), DR_ACCESS_FN (drb, i),
3567 ddr, pb, maybe_dependent))
3569 else if (*maybe_dependent == false)
3571 /* There is no dependence. */
3572 DDR_ARE_DEPENDENT (ddr) = chrec_known;
3577 /* Insert inequalities: constraints corresponding to the iteration
3578 domain, i.e. the loops surrounding the references "loop_x" and
3579 the distance variables "dx". The layout of the OMEGA
3580 representation is as follows:
3581 - coef[0] is the constant
3582 - coef[1..nb_loops] are the protected variables that will not be
3583 removed by the solver: the "dx"
3584 - coef[nb_loops + 1, 2*nb_loops] are the loop variables: "loop_x".
3586 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3587 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3589 HOST_WIDE_INT nbi = estimated_loop_iterations_int (loopi, false);
3592 ineq = omega_add_zero_geq (pb, omega_black);
3593 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3595 /* 0 <= loop_x + dx */
3596 ineq = omega_add_zero_geq (pb, omega_black);
3597 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3598 pb->geqs[ineq].coef[i + 1] = 1;
3602 /* loop_x <= nb_iters */
3603 ineq = omega_add_zero_geq (pb, omega_black);
3604 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3605 pb->geqs[ineq].coef[0] = nbi;
3607 /* loop_x + dx <= nb_iters */
3608 ineq = omega_add_zero_geq (pb, omega_black);
3609 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3610 pb->geqs[ineq].coef[i + 1] = -1;
3611 pb->geqs[ineq].coef[0] = nbi;
3613 /* A step "dx" bigger than nb_iters is not feasible, so
3614 add "0 <= nb_iters + dx", */
3615 ineq = omega_add_zero_geq (pb, omega_black);
3616 pb->geqs[ineq].coef[i + 1] = 1;
3617 pb->geqs[ineq].coef[0] = nbi;
3618 /* and "dx <= nb_iters". */
3619 ineq = omega_add_zero_geq (pb, omega_black);
3620 pb->geqs[ineq].coef[i + 1] = -1;
3621 pb->geqs[ineq].coef[0] = nbi;
3625 omega_extract_distance_vectors (pb, ddr);
3630 /* Sets up the Omega dependence problem for the data dependence
3631 relation DDR. Returns false when the constraint system cannot be
3632 built, ie. when the test answers "don't know". Returns true
3633 otherwise, and when independence has been proved (using one of the
3634 trivial dependence test), set MAYBE_DEPENDENT to false, otherwise
3635 set MAYBE_DEPENDENT to true.
3637 Example: for setting up the dependence system corresponding to the
3638 conflicting accesses
3643 | ... A[2*j, 2*(i + j)]
3647 the following constraints come from the iteration domain:
3654 where di, dj are the distance variables. The constraints
3655 representing the conflicting elements are:
3658 i + 1 = 2 * (i + di + j + dj)
3660 For asking that the resulting distance vector (di, dj) be
3661 lexicographically positive, we insert the constraint "di >= 0". If
3662 "di = 0" in the solution, we fix that component to zero, and we
3663 look at the inner loops: we set a new problem where all the outer
3664 loop distances are zero, and fix this inner component to be
3665 positive. When one of the components is positive, we save that
3666 distance, and set a new problem where the distance on this loop is
3667 zero, searching for other distances in the inner loops. Here is
3668 the classic example that illustrates that we have to set for each
3669 inner loop a new problem:
3677 we have to save two distances (1, 0) and (0, 1).
3679 Given two array references, refA and refB, we have to set the
3680 dependence problem twice, refA vs. refB and refB vs. refA, and we
3681 cannot do a single test, as refB might occur before refA in the
3682 inner loops, and the contrary when considering outer loops: ex.
3687 | T[{1,+,1}_2][{1,+,1}_1] // refA
3688 | T[{2,+,1}_2][{0,+,1}_1] // refB
3693 refB touches the elements in T before refA, and thus for the same
3694 loop_0 refB precedes refA: ie. the distance vector (0, 1, -1)
3695 but for successive loop_0 iterations, we have (1, -1, 1)
3697 The Omega solver expects the distance variables ("di" in the
3698 previous example) to come first in the constraint system (as
3699 variables to be protected, or "safe" variables), the constraint
3700 system is built using the following layout:
3702 "cst | distance vars | index vars".
3706 init_omega_for_ddr (struct data_dependence_relation *ddr,
3707 bool *maybe_dependent)
3712 *maybe_dependent = true;
3714 if (same_access_functions (ddr))
3717 lambda_vector dir_v;
3719 /* Save the 0 vector. */
3720 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3721 dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3722 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3723 dir_v[j] = dir_equal;
3724 save_dir_v (ddr, dir_v);
3726 /* Save the dependences carried by outer loops. */
3727 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3728 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3730 omega_free_problem (pb);
3734 /* Omega expects the protected variables (those that have to be kept
3735 after elimination) to appear first in the constraint system.
3736 These variables are the distance variables. In the following
3737 initialization we declare NB_LOOPS safe variables, and the total
3738 number of variables for the constraint system is 2*NB_LOOPS. */
3739 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3740 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3742 omega_free_problem (pb);
3744 /* Stop computation if not decidable, or no dependence. */
3745 if (res == false || *maybe_dependent == false)
3748 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3749 res = init_omega_for_ddr_1 (DDR_B (ddr), DDR_A (ddr), ddr, pb,
3751 omega_free_problem (pb);
3756 /* Return true when DDR contains the same information as that stored
3757 in DIR_VECTS and in DIST_VECTS, return false otherwise. */
3760 ddr_consistent_p (FILE *file,
3761 struct data_dependence_relation *ddr,
3762 VEC (lambda_vector, heap) *dist_vects,
3763 VEC (lambda_vector, heap) *dir_vects)
3767 /* If dump_file is set, output there. */
3768 if (dump_file && (dump_flags & TDF_DETAILS))
3771 if (VEC_length (lambda_vector, dist_vects) != DDR_NUM_DIST_VECTS (ddr))
3773 lambda_vector b_dist_v;
3774 fprintf (file, "\n(Number of distance vectors differ: Banerjee has %d, Omega has %d.\n",
3775 VEC_length (lambda_vector, dist_vects),
3776 DDR_NUM_DIST_VECTS (ddr));
3778 fprintf (file, "Banerjee dist vectors:\n");
3779 for (i = 0; VEC_iterate (lambda_vector, dist_vects, i, b_dist_v); i++)
3780 print_lambda_vector (file, b_dist_v, DDR_NB_LOOPS (ddr));
3782 fprintf (file, "Omega dist vectors:\n");
3783 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3784 print_lambda_vector (file, DDR_DIST_VECT (ddr, i), DDR_NB_LOOPS (ddr));
3786 fprintf (file, "data dependence relation:\n");
3787 dump_data_dependence_relation (file, ddr);
3789 fprintf (file, ")\n");
3793 if (VEC_length (lambda_vector, dir_vects) != DDR_NUM_DIR_VECTS (ddr))
3795 fprintf (file, "\n(Number of direction vectors differ: Banerjee has %d, Omega has %d.)\n",
3796 VEC_length (lambda_vector, dir_vects),
3797 DDR_NUM_DIR_VECTS (ddr));
3801 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3803 lambda_vector a_dist_v;
3804 lambda_vector b_dist_v = DDR_DIST_VECT (ddr, i);
3806 /* Distance vectors are not ordered in the same way in the DDR
3807 and in the DIST_VECTS: search for a matching vector. */
3808 for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, a_dist_v); j++)
3809 if (lambda_vector_equal (a_dist_v, b_dist_v, DDR_NB_LOOPS (ddr)))
3812 if (j == VEC_length (lambda_vector, dist_vects))
3814 fprintf (file, "\n(Dist vectors from the first dependence analyzer:\n");
3815 print_dist_vectors (file, dist_vects, DDR_NB_LOOPS (ddr));
3816 fprintf (file, "not found in Omega dist vectors:\n");
3817 print_dist_vectors (file, DDR_DIST_VECTS (ddr), DDR_NB_LOOPS (ddr));
3818 fprintf (file, "data dependence relation:\n");
3819 dump_data_dependence_relation (file, ddr);
3820 fprintf (file, ")\n");
3824 for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++)
3826 lambda_vector a_dir_v;
3827 lambda_vector b_dir_v = DDR_DIR_VECT (ddr, i);
3829 /* Direction vectors are not ordered in the same way in the DDR
3830 and in the DIR_VECTS: search for a matching vector. */
3831 for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, a_dir_v); j++)
3832 if (lambda_vector_equal (a_dir_v, b_dir_v, DDR_NB_LOOPS (ddr)))
3835 if (j == VEC_length (lambda_vector, dist_vects))
3837 fprintf (file, "\n(Dir vectors from the first dependence analyzer:\n");
3838 print_dir_vectors (file, dir_vects, DDR_NB_LOOPS (ddr));
3839 fprintf (file, "not found in Omega dir vectors:\n");
3840 print_dir_vectors (file, DDR_DIR_VECTS (ddr), DDR_NB_LOOPS (ddr));
3841 fprintf (file, "data dependence relation:\n");
3842 dump_data_dependence_relation (file, ddr);
3843 fprintf (file, ")\n");
3850 /* This computes the affine dependence relation between A and B with
3851 respect to LOOP_NEST. CHREC_KNOWN is used for representing the
3852 independence between two accesses, while CHREC_DONT_KNOW is used
3853 for representing the unknown relation.
3855 Note that it is possible to stop the computation of the dependence
3856 relation the first time we detect a CHREC_KNOWN element for a given
3860 compute_affine_dependence (struct data_dependence_relation *ddr,
3861 struct loop *loop_nest)
3863 struct data_reference *dra = DDR_A (ddr);
3864 struct data_reference *drb = DDR_B (ddr);
3866 if (dump_file && (dump_flags & TDF_DETAILS))
3868 fprintf (dump_file, "(compute_affine_dependence\n");
3869 fprintf (dump_file, " (stmt_a = \n");
3870 print_gimple_stmt (dump_file, DR_STMT (dra), 0, 0);
3871 fprintf (dump_file, ")\n (stmt_b = \n");
3872 print_gimple_stmt (dump_file, DR_STMT (drb), 0, 0);
3873 fprintf (dump_file, ")\n");
3876 /* Analyze only when the dependence relation is not yet known. */
3877 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE
3878 && !DDR_SELF_REFERENCE (ddr))
3880 dependence_stats.num_dependence_tests++;
3882 if (access_functions_are_affine_or_constant_p (dra, loop_nest)
3883 && access_functions_are_affine_or_constant_p (drb, loop_nest))
3885 if (flag_check_data_deps)
3887 /* Compute the dependences using the first algorithm. */
3888 subscript_dependence_tester (ddr, loop_nest);
3890 if (dump_file && (dump_flags & TDF_DETAILS))
3892 fprintf (dump_file, "\n\nBanerjee Analyzer\n");
3893 dump_data_dependence_relation (dump_file, ddr);
3896 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
3898 bool maybe_dependent;
3899 VEC (lambda_vector, heap) *dir_vects, *dist_vects;
3901 /* Save the result of the first DD analyzer. */
3902 dist_vects = DDR_DIST_VECTS (ddr);
3903 dir_vects = DDR_DIR_VECTS (ddr);
3905 /* Reset the information. */
3906 DDR_DIST_VECTS (ddr) = NULL;
3907 DDR_DIR_VECTS (ddr) = NULL;
3909 /* Compute the same information using Omega. */
3910 if (!init_omega_for_ddr (ddr, &maybe_dependent))
3911 goto csys_dont_know;
3913 if (dump_file && (dump_flags & TDF_DETAILS))
3915 fprintf (dump_file, "Omega Analyzer\n");
3916 dump_data_dependence_relation (dump_file, ddr);
3919 /* Check that we get the same information. */
3920 if (maybe_dependent)
3921 gcc_assert (ddr_consistent_p (stderr, ddr, dist_vects,
3926 subscript_dependence_tester (ddr, loop_nest);
3929 /* As a last case, if the dependence cannot be determined, or if
3930 the dependence is considered too difficult to determine, answer
3935 dependence_stats.num_dependence_undetermined++;
3937 if (dump_file && (dump_flags & TDF_DETAILS))
3939 fprintf (dump_file, "Data ref a:\n");
3940 dump_data_reference (dump_file, dra);
3941 fprintf (dump_file, "Data ref b:\n");
3942 dump_data_reference (dump_file, drb);
3943 fprintf (dump_file, "affine dependence test not usable: access function not affine or constant.\n");
3945 finalize_ddr_dependent (ddr, chrec_dont_know);
3949 if (dump_file && (dump_flags & TDF_DETAILS))
3950 fprintf (dump_file, ")\n");
3953 /* This computes the dependence relation for the same data
3954 reference into DDR. */
3957 compute_self_dependence (struct data_dependence_relation *ddr)
3960 struct subscript *subscript;
3962 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3965 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3968 if (SUB_CONFLICTS_IN_A (subscript))
3969 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3970 if (SUB_CONFLICTS_IN_B (subscript))
3971 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3973 /* The accessed index overlaps for each iteration. */
3974 SUB_CONFLICTS_IN_A (subscript)
3975 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3976 SUB_CONFLICTS_IN_B (subscript)
3977 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3978 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
3981 /* The distance vector is the zero vector. */
3982 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3983 save_dir_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3986 /* Compute in DEPENDENCE_RELATIONS the data dependence graph for all
3987 the data references in DATAREFS, in the LOOP_NEST. When
3988 COMPUTE_SELF_AND_RR is FALSE, don't compute read-read and self
3992 compute_all_dependences (VEC (data_reference_p, heap) *datarefs,
3993 VEC (ddr_p, heap) **dependence_relations,
3994 VEC (loop_p, heap) *loop_nest,
3995 bool compute_self_and_rr)
3997 struct data_dependence_relation *ddr;
3998 struct data_reference *a, *b;
4001 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4002 for (j = i + 1; VEC_iterate (data_reference_p, datarefs, j, b); j++)
4003 if (!DR_IS_READ (a) || !DR_IS_READ (b) || compute_self_and_rr)
4005 ddr = initialize_data_dependence_relation (a, b, loop_nest);
4006 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4007 compute_affine_dependence (ddr, VEC_index (loop_p, loop_nest, 0));
4010 if (compute_self_and_rr)
4011 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4013 ddr = initialize_data_dependence_relation (a, a, loop_nest);
4014 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4015 compute_self_dependence (ddr);
4019 /* Stores the locations of memory references in STMT to REFERENCES. Returns
4020 true if STMT clobbers memory, false otherwise. */
4023 get_references_in_stmt (gimple stmt, VEC (data_ref_loc, heap) **references)
4025 bool clobbers_memory = false;
4028 enum gimple_code stmt_code = gimple_code (stmt);
4032 /* ASM_EXPR and CALL_EXPR may embed arbitrary side effects.
4033 Calls have side-effects, except those to const or pure
4035 if ((stmt_code == GIMPLE_CALL
4036 && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
4037 || (stmt_code == GIMPLE_ASM
4038 && gimple_asm_volatile_p (stmt)))
4039 clobbers_memory = true;
4041 if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
4042 return clobbers_memory;
4044 if (stmt_code == GIMPLE_ASSIGN)
4047 op0 = gimple_assign_lhs_ptr (stmt);
4048 op1 = gimple_assign_rhs1_ptr (stmt);
4051 || (REFERENCE_CLASS_P (*op1)
4052 && (base = get_base_address (*op1))
4053 && TREE_CODE (base) != SSA_NAME))
4055 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4057 ref->is_read = true;
4061 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4063 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4065 ref->is_read = false;
4068 else if (stmt_code == GIMPLE_CALL)
4070 unsigned i, n = gimple_call_num_args (stmt);
4072 for (i = 0; i < n; i++)
4074 op0 = gimple_call_arg_ptr (stmt, i);
4077 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4079 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4081 ref->is_read = true;
4086 return clobbers_memory;
4089 /* Stores the data references in STMT to DATAREFS. If there is an unanalyzable
4090 reference, returns false, otherwise returns true. NEST is the outermost
4091 loop of the loop nest in which the references should be analyzed. */
4094 find_data_references_in_stmt (struct loop *nest, gimple stmt,
4095 VEC (data_reference_p, heap) **datarefs)
4098 VEC (data_ref_loc, heap) *references;
4101 data_reference_p dr;
4103 if (get_references_in_stmt (stmt, &references))
4105 VEC_free (data_ref_loc, heap, references);
4109 for (i = 0; VEC_iterate (data_ref_loc, references, i, ref); i++)
4111 dr = create_data_ref (nest, *ref->pos, stmt, ref->is_read);
4112 gcc_assert (dr != NULL);
4114 /* FIXME -- data dependence analysis does not work correctly for objects with
4115 invariant addresses. Let us fail here until the problem is fixed. */
4116 if (dr_address_invariant_p (dr))
4119 if (dump_file && (dump_flags & TDF_DETAILS))
4120 fprintf (dump_file, "\tFAILED as dr address is invariant\n");
4125 VEC_safe_push (data_reference_p, heap, *datarefs, dr);
4127 VEC_free (data_ref_loc, heap, references);
4131 /* Search the data references in LOOP, and record the information into
4132 DATAREFS. Returns chrec_dont_know when failing to analyze a
4133 difficult case, returns NULL_TREE otherwise.
4135 TODO: This function should be made smarter so that it can handle address
4136 arithmetic as if they were array accesses, etc. */
4139 find_data_references_in_loop (struct loop *loop,
4140 VEC (data_reference_p, heap) **datarefs)
4142 basic_block bb, *bbs;
4144 gimple_stmt_iterator bsi;
4146 bbs = get_loop_body_in_dom_order (loop);
4148 for (i = 0; i < loop->num_nodes; i++)
4152 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4154 gimple stmt = gsi_stmt (bsi);
4156 if (!find_data_references_in_stmt (loop, stmt, datarefs))
4158 struct data_reference *res;
4159 res = XCNEW (struct data_reference);
4160 VEC_safe_push (data_reference_p, heap, *datarefs, res);
4163 return chrec_dont_know;
4172 /* Recursive helper function. */
4175 find_loop_nest_1 (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4177 /* Inner loops of the nest should not contain siblings. Example:
4178 when there are two consecutive loops,
4189 the dependence relation cannot be captured by the distance
4194 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4196 return find_loop_nest_1 (loop->inner, loop_nest);
4200 /* Return false when the LOOP is not well nested. Otherwise return
4201 true and insert in LOOP_NEST the loops of the nest. LOOP_NEST will
4202 contain the loops from the outermost to the innermost, as they will
4203 appear in the classic distance vector. */
4206 find_loop_nest (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4208 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4210 return find_loop_nest_1 (loop->inner, loop_nest);
4214 /* Returns true when the data dependences have been computed, false otherwise.
4215 Given a loop nest LOOP, the following vectors are returned:
4216 DATAREFS is initialized to all the array elements contained in this loop,
4217 DEPENDENCE_RELATIONS contains the relations between the data references.
4218 Compute read-read and self relations if
4219 COMPUTE_SELF_AND_READ_READ_DEPENDENCES is TRUE. */
4222 compute_data_dependences_for_loop (struct loop *loop,
4223 bool compute_self_and_read_read_dependences,
4224 VEC (data_reference_p, heap) **datarefs,
4225 VEC (ddr_p, heap) **dependence_relations)
4228 VEC (loop_p, heap) *vloops = VEC_alloc (loop_p, heap, 3);
4230 memset (&dependence_stats, 0, sizeof (dependence_stats));
4232 /* If the loop nest is not well formed, or one of the data references
4233 is not computable, give up without spending time to compute other
4236 || !find_loop_nest (loop, &vloops)
4237 || find_data_references_in_loop (loop, datarefs) == chrec_dont_know)
4239 struct data_dependence_relation *ddr;
4241 /* Insert a single relation into dependence_relations:
4243 ddr = initialize_data_dependence_relation (NULL, NULL, vloops);
4244 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4248 compute_all_dependences (*datarefs, dependence_relations, vloops,
4249 compute_self_and_read_read_dependences);
4251 if (dump_file && (dump_flags & TDF_STATS))
4253 fprintf (dump_file, "Dependence tester statistics:\n");
4255 fprintf (dump_file, "Number of dependence tests: %d\n",
4256 dependence_stats.num_dependence_tests);
4257 fprintf (dump_file, "Number of dependence tests classified dependent: %d\n",
4258 dependence_stats.num_dependence_dependent);
4259 fprintf (dump_file, "Number of dependence tests classified independent: %d\n",
4260 dependence_stats.num_dependence_independent);
4261 fprintf (dump_file, "Number of undetermined dependence tests: %d\n",
4262 dependence_stats.num_dependence_undetermined);
4264 fprintf (dump_file, "Number of subscript tests: %d\n",
4265 dependence_stats.num_subscript_tests);
4266 fprintf (dump_file, "Number of undetermined subscript tests: %d\n",
4267 dependence_stats.num_subscript_undetermined);
4268 fprintf (dump_file, "Number of same subscript function: %d\n",
4269 dependence_stats.num_same_subscript_function);
4271 fprintf (dump_file, "Number of ziv tests: %d\n",
4272 dependence_stats.num_ziv);
4273 fprintf (dump_file, "Number of ziv tests returning dependent: %d\n",
4274 dependence_stats.num_ziv_dependent);
4275 fprintf (dump_file, "Number of ziv tests returning independent: %d\n",
4276 dependence_stats.num_ziv_independent);
4277 fprintf (dump_file, "Number of ziv tests unimplemented: %d\n",
4278 dependence_stats.num_ziv_unimplemented);
4280 fprintf (dump_file, "Number of siv tests: %d\n",
4281 dependence_stats.num_siv);
4282 fprintf (dump_file, "Number of siv tests returning dependent: %d\n",
4283 dependence_stats.num_siv_dependent);
4284 fprintf (dump_file, "Number of siv tests returning independent: %d\n",
4285 dependence_stats.num_siv_independent);
4286 fprintf (dump_file, "Number of siv tests unimplemented: %d\n",
4287 dependence_stats.num_siv_unimplemented);
4289 fprintf (dump_file, "Number of miv tests: %d\n",
4290 dependence_stats.num_miv);
4291 fprintf (dump_file, "Number of miv tests returning dependent: %d\n",
4292 dependence_stats.num_miv_dependent);
4293 fprintf (dump_file, "Number of miv tests returning independent: %d\n",
4294 dependence_stats.num_miv_independent);
4295 fprintf (dump_file, "Number of miv tests unimplemented: %d\n",
4296 dependence_stats.num_miv_unimplemented);
4302 /* Entry point (for testing only). Analyze all the data references
4303 and the dependence relations in LOOP.
4305 The data references are computed first.
4307 A relation on these nodes is represented by a complete graph. Some
4308 of the relations could be of no interest, thus the relations can be
4311 In the following function we compute all the relations. This is
4312 just a first implementation that is here for:
4313 - for showing how to ask for the dependence relations,
4314 - for the debugging the whole dependence graph,
4315 - for the dejagnu testcases and maintenance.
4317 It is possible to ask only for a part of the graph, avoiding to
4318 compute the whole dependence graph. The computed dependences are
4319 stored in a knowledge base (KB) such that later queries don't
4320 recompute the same information. The implementation of this KB is
4321 transparent to the optimizer, and thus the KB can be changed with a
4322 more efficient implementation, or the KB could be disabled. */
4324 analyze_all_data_dependences (struct loop *loop)
4327 int nb_data_refs = 10;
4328 VEC (data_reference_p, heap) *datarefs =
4329 VEC_alloc (data_reference_p, heap, nb_data_refs);
4330 VEC (ddr_p, heap) *dependence_relations =
4331 VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs);
4333 /* Compute DDs on the whole function. */
4334 compute_data_dependences_for_loop (loop, false, &datarefs,
4335 &dependence_relations);
4339 dump_data_dependence_relations (dump_file, dependence_relations);
4340 fprintf (dump_file, "\n\n");
4342 if (dump_flags & TDF_DETAILS)
4343 dump_dist_dir_vectors (dump_file, dependence_relations);
4345 if (dump_flags & TDF_STATS)
4347 unsigned nb_top_relations = 0;
4348 unsigned nb_bot_relations = 0;
4349 unsigned nb_basename_differ = 0;
4350 unsigned nb_chrec_relations = 0;
4351 struct data_dependence_relation *ddr;
4353 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4355 if (chrec_contains_undetermined (DDR_ARE_DEPENDENT (ddr)))
4358 else if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
4360 struct data_reference *a = DDR_A (ddr);
4361 struct data_reference *b = DDR_B (ddr);
4363 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
4364 nb_basename_differ++;
4370 nb_chrec_relations++;
4373 gather_stats_on_scev_database ();
4377 free_dependence_relations (dependence_relations);
4378 free_data_refs (datarefs);
4381 /* Computes all the data dependences and check that the results of
4382 several analyzers are the same. */
4385 tree_check_data_deps (void)
4388 struct loop *loop_nest;
4390 FOR_EACH_LOOP (li, loop_nest, 0)
4391 analyze_all_data_dependences (loop_nest);
4394 /* Free the memory used by a data dependence relation DDR. */
4397 free_dependence_relation (struct data_dependence_relation *ddr)
4402 if (DDR_SUBSCRIPTS (ddr))
4403 free_subscripts (DDR_SUBSCRIPTS (ddr));
4404 if (DDR_DIST_VECTS (ddr))
4405 VEC_free (lambda_vector, heap, DDR_DIST_VECTS (ddr));
4406 if (DDR_DIR_VECTS (ddr))
4407 VEC_free (lambda_vector, heap, DDR_DIR_VECTS (ddr));
4412 /* Free the memory used by the data dependence relations from
4413 DEPENDENCE_RELATIONS. */
4416 free_dependence_relations (VEC (ddr_p, heap) *dependence_relations)
4419 struct data_dependence_relation *ddr;
4420 VEC (loop_p, heap) *loop_nest = NULL;
4422 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4426 if (loop_nest == NULL)
4427 loop_nest = DDR_LOOP_NEST (ddr);
4429 gcc_assert (DDR_LOOP_NEST (ddr) == NULL
4430 || DDR_LOOP_NEST (ddr) == loop_nest);
4431 free_dependence_relation (ddr);
4435 VEC_free (loop_p, heap, loop_nest);
4436 VEC_free (ddr_p, heap, dependence_relations);
4439 /* Free the memory used by the data references from DATAREFS. */
4442 free_data_refs (VEC (data_reference_p, heap) *datarefs)
4445 struct data_reference *dr;
4447 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
4449 VEC_free (data_reference_p, heap, datarefs);
4454 /* Dump vertex I in RDG to FILE. */
4457 dump_rdg_vertex (FILE *file, struct graph *rdg, int i)
4459 struct vertex *v = &(rdg->vertices[i]);
4460 struct graph_edge *e;
4462 fprintf (file, "(vertex %d: (%s%s) (in:", i,
4463 RDG_MEM_WRITE_STMT (rdg, i) ? "w" : "",
4464 RDG_MEM_READS_STMT (rdg, i) ? "r" : "");
4467 for (e = v->pred; e; e = e->pred_next)
4468 fprintf (file, " %d", e->src);
4470 fprintf (file, ") (out:");
4473 for (e = v->succ; e; e = e->succ_next)
4474 fprintf (file, " %d", e->dest);
4476 fprintf (file, ") \n");
4477 print_gimple_stmt (file, RDGV_STMT (v), 0, TDF_VOPS|TDF_MEMSYMS);
4478 fprintf (file, ")\n");
4481 /* Call dump_rdg_vertex on stderr. */
4484 debug_rdg_vertex (struct graph *rdg, int i)
4486 dump_rdg_vertex (stderr, rdg, i);
4489 /* Dump component C of RDG to FILE. If DUMPED is non-null, set the
4490 dumped vertices to that bitmap. */
4492 void dump_rdg_component (FILE *file, struct graph *rdg, int c, bitmap dumped)
4496 fprintf (file, "(%d\n", c);
4498 for (i = 0; i < rdg->n_vertices; i++)
4499 if (rdg->vertices[i].component == c)
4502 bitmap_set_bit (dumped, i);
4504 dump_rdg_vertex (file, rdg, i);
4507 fprintf (file, ")\n");
4510 /* Call dump_rdg_vertex on stderr. */
4513 debug_rdg_component (struct graph *rdg, int c)
4515 dump_rdg_component (stderr, rdg, c, NULL);
4518 /* Dump the reduced dependence graph RDG to FILE. */
4521 dump_rdg (FILE *file, struct graph *rdg)
4524 bitmap dumped = BITMAP_ALLOC (NULL);
4526 fprintf (file, "(rdg\n");
4528 for (i = 0; i < rdg->n_vertices; i++)
4529 if (!bitmap_bit_p (dumped, i))
4530 dump_rdg_component (file, rdg, rdg->vertices[i].component, dumped);
4532 fprintf (file, ")\n");
4533 BITMAP_FREE (dumped);
4536 /* Call dump_rdg on stderr. */
4539 debug_rdg (struct graph *rdg)
4541 dump_rdg (stderr, rdg);
4545 dot_rdg_1 (FILE *file, struct graph *rdg)
4549 fprintf (file, "digraph RDG {\n");
4551 for (i = 0; i < rdg->n_vertices; i++)
4553 struct vertex *v = &(rdg->vertices[i]);
4554 struct graph_edge *e;
4556 /* Highlight reads from memory. */
4557 if (RDG_MEM_READS_STMT (rdg, i))
4558 fprintf (file, "%d [style=filled, fillcolor=green]\n", i);
4560 /* Highlight stores to memory. */
4561 if (RDG_MEM_WRITE_STMT (rdg, i))
4562 fprintf (file, "%d [style=filled, fillcolor=red]\n", i);
4565 for (e = v->succ; e; e = e->succ_next)
4566 switch (RDGE_TYPE (e))
4569 fprintf (file, "%d -> %d [label=input] \n", i, e->dest);
4573 fprintf (file, "%d -> %d [label=output] \n", i, e->dest);
4577 /* These are the most common dependences: don't print these. */
4578 fprintf (file, "%d -> %d \n", i, e->dest);
4582 fprintf (file, "%d -> %d [label=anti] \n", i, e->dest);
4590 fprintf (file, "}\n\n");
4593 /* Display SCOP using dotty. */
4596 dot_rdg (struct graph *rdg)
4598 FILE *file = fopen ("/tmp/rdg.dot", "w");
4599 gcc_assert (file != NULL);
4601 dot_rdg_1 (file, rdg);
4604 system ("dotty /tmp/rdg.dot");
4608 /* This structure is used for recording the mapping statement index in
4611 struct rdg_vertex_info GTY(())
4617 /* Returns the index of STMT in RDG. */
4620 rdg_vertex_for_stmt (struct graph *rdg, gimple stmt)
4622 struct rdg_vertex_info rvi, *slot;
4625 slot = (struct rdg_vertex_info *) htab_find (rdg->indices, &rvi);
4633 /* Creates an edge in RDG for each distance vector from DDR. The
4634 order that we keep track of in the RDG is the order in which
4635 statements have to be executed. */
4638 create_rdg_edge_for_ddr (struct graph *rdg, ddr_p ddr)
4640 struct graph_edge *e;
4642 data_reference_p dra = DDR_A (ddr);
4643 data_reference_p drb = DDR_B (ddr);
4644 unsigned level = ddr_dependence_level (ddr);
4646 /* For non scalar dependences, when the dependence is REVERSED,
4647 statement B has to be executed before statement A. */
4649 && !DDR_REVERSED_P (ddr))
4651 data_reference_p tmp = dra;
4656 va = rdg_vertex_for_stmt (rdg, DR_STMT (dra));
4657 vb = rdg_vertex_for_stmt (rdg, DR_STMT (drb));
4659 if (va < 0 || vb < 0)
4662 e = add_edge (rdg, va, vb);
4663 e->data = XNEW (struct rdg_edge);
4665 RDGE_LEVEL (e) = level;
4666 RDGE_RELATION (e) = ddr;
4668 /* Determines the type of the data dependence. */
4669 if (DR_IS_READ (dra) && DR_IS_READ (drb))
4670 RDGE_TYPE (e) = input_dd;
4671 else if (!DR_IS_READ (dra) && !DR_IS_READ (drb))
4672 RDGE_TYPE (e) = output_dd;
4673 else if (!DR_IS_READ (dra) && DR_IS_READ (drb))
4674 RDGE_TYPE (e) = flow_dd;
4675 else if (DR_IS_READ (dra) && !DR_IS_READ (drb))
4676 RDGE_TYPE (e) = anti_dd;
4679 /* Creates dependence edges in RDG for all the uses of DEF. IDEF is
4680 the index of DEF in RDG. */
4683 create_rdg_edges_for_scalar (struct graph *rdg, tree def, int idef)
4685 use_operand_p imm_use_p;
4686 imm_use_iterator iterator;
4688 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, def)
4690 struct graph_edge *e;
4691 int use = rdg_vertex_for_stmt (rdg, USE_STMT (imm_use_p));
4696 e = add_edge (rdg, idef, use);
4697 e->data = XNEW (struct rdg_edge);
4698 RDGE_TYPE (e) = flow_dd;
4699 RDGE_RELATION (e) = NULL;
4703 /* Creates the edges of the reduced dependence graph RDG. */
4706 create_rdg_edges (struct graph *rdg, VEC (ddr_p, heap) *ddrs)
4709 struct data_dependence_relation *ddr;
4710 def_operand_p def_p;
4713 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
4714 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
4715 create_rdg_edge_for_ddr (rdg, ddr);
4717 for (i = 0; i < rdg->n_vertices; i++)
4718 FOR_EACH_PHI_OR_STMT_DEF (def_p, RDG_STMT (rdg, i),
4720 create_rdg_edges_for_scalar (rdg, DEF_FROM_PTR (def_p), i);
4723 /* Build the vertices of the reduced dependence graph RDG. */
4726 create_rdg_vertices (struct graph *rdg, VEC (gimple, heap) *stmts)
4731 for (i = 0; VEC_iterate (gimple, stmts, i, stmt); i++)
4733 VEC (data_ref_loc, heap) *references;
4735 struct vertex *v = &(rdg->vertices[i]);
4736 struct rdg_vertex_info *rvi = XNEW (struct rdg_vertex_info);
4737 struct rdg_vertex_info **slot;
4741 slot = (struct rdg_vertex_info **) htab_find_slot (rdg->indices, rvi, INSERT);
4748 v->data = XNEW (struct rdg_vertex);
4749 RDG_STMT (rdg, i) = stmt;
4751 RDG_MEM_WRITE_STMT (rdg, i) = false;
4752 RDG_MEM_READS_STMT (rdg, i) = false;
4753 if (gimple_code (stmt) == GIMPLE_PHI)
4756 get_references_in_stmt (stmt, &references);
4757 for (j = 0; VEC_iterate (data_ref_loc, references, j, ref); j++)
4759 RDG_MEM_WRITE_STMT (rdg, i) = true;
4761 RDG_MEM_READS_STMT (rdg, i) = true;
4763 VEC_free (data_ref_loc, heap, references);
4767 /* Initialize STMTS with all the statements of LOOP. When
4768 INCLUDE_PHIS is true, include also the PHI nodes. The order in
4769 which we discover statements is important as
4770 generate_loops_for_partition is using the same traversal for
4771 identifying statements. */
4774 stmts_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4777 basic_block *bbs = get_loop_body_in_dom_order (loop);
4779 for (i = 0; i < loop->num_nodes; i++)
4781 basic_block bb = bbs[i];
4782 gimple_stmt_iterator bsi;
4785 for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4786 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4788 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4790 stmt = gsi_stmt (bsi);
4791 if (gimple_code (stmt) != GIMPLE_LABEL)
4792 VEC_safe_push (gimple, heap, *stmts, stmt);
4799 /* Returns true when all the dependences are computable. */
4802 known_dependences_p (VEC (ddr_p, heap) *dependence_relations)
4807 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4808 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
4814 /* Computes a hash function for element ELT. */
4817 hash_stmt_vertex_info (const void *elt)
4819 const struct rdg_vertex_info *const rvi =
4820 (const struct rdg_vertex_info *) elt;
4821 gimple stmt = rvi->stmt;
4823 return htab_hash_pointer (stmt);
4826 /* Compares database elements E1 and E2. */
4829 eq_stmt_vertex_info (const void *e1, const void *e2)
4831 const struct rdg_vertex_info *elt1 = (const struct rdg_vertex_info *) e1;
4832 const struct rdg_vertex_info *elt2 = (const struct rdg_vertex_info *) e2;
4834 return elt1->stmt == elt2->stmt;
4837 /* Free the element E. */
4840 hash_stmt_vertex_del (void *e)
4845 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4846 statement of the loop nest, and one edge per data dependence or
4847 scalar dependence. */
4850 build_empty_rdg (int n_stmts)
4852 int nb_data_refs = 10;
4853 struct graph *rdg = new_graph (n_stmts);
4855 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4856 eq_stmt_vertex_info, hash_stmt_vertex_del);
4860 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4861 statement of the loop nest, and one edge per data dependence or
4862 scalar dependence. */
4865 build_rdg (struct loop *loop)
4867 int nb_data_refs = 10;
4868 struct graph *rdg = NULL;
4869 VEC (ddr_p, heap) *dependence_relations;
4870 VEC (data_reference_p, heap) *datarefs;
4871 VEC (gimple, heap) *stmts = VEC_alloc (gimple, heap, nb_data_refs);
4873 dependence_relations = VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs) ;
4874 datarefs = VEC_alloc (data_reference_p, heap, nb_data_refs);
4875 compute_data_dependences_for_loop (loop,
4878 &dependence_relations);
4880 if (!known_dependences_p (dependence_relations))
4882 free_dependence_relations (dependence_relations);
4883 free_data_refs (datarefs);
4884 VEC_free (gimple, heap, stmts);
4889 stmts_from_loop (loop, &stmts);
4890 rdg = build_empty_rdg (VEC_length (gimple, stmts));
4892 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4893 eq_stmt_vertex_info, hash_stmt_vertex_del);
4894 create_rdg_vertices (rdg, stmts);
4895 create_rdg_edges (rdg, dependence_relations);
4897 VEC_free (gimple, heap, stmts);
4901 /* Free the reduced dependence graph RDG. */
4904 free_rdg (struct graph *rdg)
4908 for (i = 0; i < rdg->n_vertices; i++)
4909 free (rdg->vertices[i].data);
4911 htab_delete (rdg->indices);
4915 /* Initialize STMTS with all the statements of LOOP that contain a
4919 stores_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4922 basic_block *bbs = get_loop_body_in_dom_order (loop);
4924 for (i = 0; i < loop->num_nodes; i++)
4926 basic_block bb = bbs[i];
4927 gimple_stmt_iterator bsi;
4929 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4930 if (!ZERO_SSA_OPERANDS (gsi_stmt (bsi), SSA_OP_VDEF))
4931 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4937 /* For a data reference REF, return the declaration of its base
4938 address or NULL_TREE if the base is not determined. */
4941 ref_base_address (gimple stmt, data_ref_loc *ref)
4943 tree base = NULL_TREE;
4945 struct data_reference *dr = XCNEW (struct data_reference);
4947 DR_STMT (dr) = stmt;
4948 DR_REF (dr) = *ref->pos;
4949 dr_analyze_innermost (dr);
4950 base_address = DR_BASE_ADDRESS (dr);
4955 switch (TREE_CODE (base_address))
4958 base = TREE_OPERAND (base_address, 0);
4962 base = base_address;
4971 /* Determines whether the statement from vertex V of the RDG has a
4972 definition used outside the loop that contains this statement. */
4975 rdg_defs_used_in_other_loops_p (struct graph *rdg, int v)
4977 gimple stmt = RDG_STMT (rdg, v);
4978 struct loop *loop = loop_containing_stmt (stmt);
4979 use_operand_p imm_use_p;
4980 imm_use_iterator iterator;
4982 def_operand_p def_p;
4987 FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, it, SSA_OP_DEF)
4989 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, DEF_FROM_PTR (def_p))
4991 if (loop_containing_stmt (USE_STMT (imm_use_p)) != loop)
4999 /* Determines whether statements S1 and S2 access to similar memory
5000 locations. Two memory accesses are considered similar when they
5001 have the same base address declaration, i.e. when their
5002 ref_base_address is the same. */
5005 have_similar_memory_accesses (gimple s1, gimple s2)
5009 VEC (data_ref_loc, heap) *refs1, *refs2;
5010 data_ref_loc *ref1, *ref2;
5012 get_references_in_stmt (s1, &refs1);
5013 get_references_in_stmt (s2, &refs2);
5015 for (i = 0; VEC_iterate (data_ref_loc, refs1, i, ref1); i++)
5017 tree base1 = ref_base_address (s1, ref1);
5020 for (j = 0; VEC_iterate (data_ref_loc, refs2, j, ref2); j++)
5021 if (base1 == ref_base_address (s2, ref2))
5029 VEC_free (data_ref_loc, heap, refs1);
5030 VEC_free (data_ref_loc, heap, refs2);
5034 /* Helper function for the hashtab. */
5037 have_similar_memory_accesses_1 (const void *s1, const void *s2)
5039 return have_similar_memory_accesses (CONST_CAST_GIMPLE ((const_gimple) s1),
5040 CONST_CAST_GIMPLE ((const_gimple) s2));
5043 /* Helper function for the hashtab. */
5046 ref_base_address_1 (const void *s)
5048 gimple stmt = CONST_CAST_GIMPLE ((const_gimple) s);
5050 VEC (data_ref_loc, heap) *refs;
5054 get_references_in_stmt (stmt, &refs);
5056 for (i = 0; VEC_iterate (data_ref_loc, refs, i, ref); i++)
5059 res = htab_hash_pointer (ref_base_address (stmt, ref));
5063 VEC_free (data_ref_loc, heap, refs);
5067 /* Try to remove duplicated write data references from STMTS. */
5070 remove_similar_memory_refs (VEC (gimple, heap) **stmts)
5074 htab_t seen = htab_create (VEC_length (gimple, *stmts), ref_base_address_1,
5075 have_similar_memory_accesses_1, NULL);
5077 for (i = 0; VEC_iterate (gimple, *stmts, i, stmt); )
5081 slot = htab_find_slot (seen, stmt, INSERT);
5084 VEC_ordered_remove (gimple, *stmts, i);
5087 *slot = (void *) stmt;
5095 /* Returns the index of PARAMETER in the parameters vector of the
5096 ACCESS_MATRIX. If PARAMETER does not exist return -1. */
5099 access_matrix_get_index_for_parameter (tree parameter,
5100 struct access_matrix *access_matrix)
5103 VEC (tree,heap) *lambda_parameters = AM_PARAMETERS (access_matrix);
5104 tree lambda_parameter;
5106 for (i = 0; VEC_iterate (tree, lambda_parameters, i, lambda_parameter); i++)
5107 if (lambda_parameter == parameter)
5108 return i + AM_NB_INDUCTION_VARS (access_matrix);