1 /* Data references and dependences detectors.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
3 Free Software Foundation, Inc.
4 Contributed by Sebastian Pop <pop@cri.ensmp.fr>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This pass walks a given loop structure searching for array
23 references. The information about the array accesses is recorded
24 in DATA_REFERENCE structures.
26 The basic test for determining the dependences is:
27 given two access functions chrec1 and chrec2 to a same array, and
28 x and y two vectors from the iteration domain, the same element of
29 the array is accessed twice at iterations x and y if and only if:
30 | chrec1 (x) == chrec2 (y).
32 The goals of this analysis are:
34 - to determine the independence: the relation between two
35 independent accesses is qualified with the chrec_known (this
36 information allows a loop parallelization),
38 - when two data references access the same data, to qualify the
39 dependence relation with classic dependence representations:
43 - loop carried level dependence
44 - polyhedron dependence
45 or with the chains of recurrences based representation,
47 - to define a knowledge base for storing the data dependence
50 - to define an interface to access this data.
55 - subscript: given two array accesses a subscript is the tuple
56 composed of the access functions for a given dimension. Example:
57 Given A[f1][f2][f3] and B[g1][g2][g3], there are three subscripts:
58 (f1, g1), (f2, g2), (f3, g3).
60 - Diophantine equation: an equation whose coefficients and
61 solutions are integer constants, for example the equation
63 has an integer solution x = 1 and y = -1.
67 - "Advanced Compilation for High Performance Computing" by Randy
68 Allen and Ken Kennedy.
69 http://citeseer.ist.psu.edu/goff91practical.html
71 - "Loop Transformations for Restructuring Compilers - The Foundations"
79 #include "coretypes.h"
84 /* These RTL headers are needed for basic-block.h. */
86 #include "basic-block.h"
87 #include "diagnostic.h"
88 #include "tree-flow.h"
89 #include "tree-dump.h"
92 #include "tree-data-ref.h"
93 #include "tree-scalar-evolution.h"
94 #include "tree-pass.h"
95 #include "langhooks.h"
97 static struct datadep_stats
99 int num_dependence_tests;
100 int num_dependence_dependent;
101 int num_dependence_independent;
102 int num_dependence_undetermined;
104 int num_subscript_tests;
105 int num_subscript_undetermined;
106 int num_same_subscript_function;
109 int num_ziv_independent;
110 int num_ziv_dependent;
111 int num_ziv_unimplemented;
114 int num_siv_independent;
115 int num_siv_dependent;
116 int num_siv_unimplemented;
119 int num_miv_independent;
120 int num_miv_dependent;
121 int num_miv_unimplemented;
124 static bool subscript_dependence_tester_1 (struct data_dependence_relation *,
125 struct data_reference *,
126 struct data_reference *,
128 /* Returns true iff A divides B. */
131 tree_fold_divides_p (const_tree a, const_tree b)
133 gcc_assert (TREE_CODE (a) == INTEGER_CST);
134 gcc_assert (TREE_CODE (b) == INTEGER_CST);
135 return integer_zerop (int_const_binop (TRUNC_MOD_EXPR, b, a, 0));
138 /* Returns true iff A divides B. */
141 int_divides_p (int a, int b)
143 return ((b % a) == 0);
148 /* Dump into FILE all the data references from DATAREFS. */
151 dump_data_references (FILE *file, VEC (data_reference_p, heap) *datarefs)
154 struct data_reference *dr;
156 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
157 dump_data_reference (file, dr);
160 /* Dump to STDERR all the dependence relations from DDRS. */
163 debug_data_dependence_relations (VEC (ddr_p, heap) *ddrs)
165 dump_data_dependence_relations (stderr, ddrs);
168 /* Dump into FILE all the dependence relations from DDRS. */
171 dump_data_dependence_relations (FILE *file,
172 VEC (ddr_p, heap) *ddrs)
175 struct data_dependence_relation *ddr;
177 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
178 dump_data_dependence_relation (file, ddr);
181 /* Dump function for a DATA_REFERENCE structure. */
184 dump_data_reference (FILE *outf,
185 struct data_reference *dr)
189 fprintf (outf, "(Data Ref: \n stmt: ");
190 print_gimple_stmt (outf, DR_STMT (dr), 0, 0);
191 fprintf (outf, " ref: ");
192 print_generic_stmt (outf, DR_REF (dr), 0);
193 fprintf (outf, " base_object: ");
194 print_generic_stmt (outf, DR_BASE_OBJECT (dr), 0);
196 for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++)
198 fprintf (outf, " Access function %d: ", i);
199 print_generic_stmt (outf, DR_ACCESS_FN (dr, i), 0);
201 fprintf (outf, ")\n");
204 /* Dumps the affine function described by FN to the file OUTF. */
207 dump_affine_function (FILE *outf, affine_fn fn)
212 print_generic_expr (outf, VEC_index (tree, fn, 0), TDF_SLIM);
213 for (i = 1; VEC_iterate (tree, fn, i, coef); i++)
215 fprintf (outf, " + ");
216 print_generic_expr (outf, coef, TDF_SLIM);
217 fprintf (outf, " * x_%u", i);
221 /* Dumps the conflict function CF to the file OUTF. */
224 dump_conflict_function (FILE *outf, conflict_function *cf)
228 if (cf->n == NO_DEPENDENCE)
229 fprintf (outf, "no dependence\n");
230 else if (cf->n == NOT_KNOWN)
231 fprintf (outf, "not known\n");
234 for (i = 0; i < cf->n; i++)
237 dump_affine_function (outf, cf->fns[i]);
238 fprintf (outf, "]\n");
243 /* Dump function for a SUBSCRIPT structure. */
246 dump_subscript (FILE *outf, struct subscript *subscript)
248 conflict_function *cf = SUB_CONFLICTS_IN_A (subscript);
250 fprintf (outf, "\n (subscript \n");
251 fprintf (outf, " iterations_that_access_an_element_twice_in_A: ");
252 dump_conflict_function (outf, cf);
253 if (CF_NONTRIVIAL_P (cf))
255 tree last_iteration = SUB_LAST_CONFLICT (subscript);
256 fprintf (outf, " last_conflict: ");
257 print_generic_stmt (outf, last_iteration, 0);
260 cf = SUB_CONFLICTS_IN_B (subscript);
261 fprintf (outf, " iterations_that_access_an_element_twice_in_B: ");
262 dump_conflict_function (outf, cf);
263 if (CF_NONTRIVIAL_P (cf))
265 tree last_iteration = SUB_LAST_CONFLICT (subscript);
266 fprintf (outf, " last_conflict: ");
267 print_generic_stmt (outf, last_iteration, 0);
270 fprintf (outf, " (Subscript distance: ");
271 print_generic_stmt (outf, SUB_DISTANCE (subscript), 0);
272 fprintf (outf, " )\n");
273 fprintf (outf, " )\n");
276 /* Print the classic direction vector DIRV to OUTF. */
279 print_direction_vector (FILE *outf,
285 for (eq = 0; eq < length; eq++)
287 enum data_dependence_direction dir = dirv[eq];
292 fprintf (outf, " +");
295 fprintf (outf, " -");
298 fprintf (outf, " =");
300 case dir_positive_or_equal:
301 fprintf (outf, " +=");
303 case dir_positive_or_negative:
304 fprintf (outf, " +-");
306 case dir_negative_or_equal:
307 fprintf (outf, " -=");
310 fprintf (outf, " *");
313 fprintf (outf, "indep");
317 fprintf (outf, "\n");
320 /* Print a vector of direction vectors. */
323 print_dir_vectors (FILE *outf, VEC (lambda_vector, heap) *dir_vects,
329 for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, v); j++)
330 print_direction_vector (outf, v, length);
333 /* Print a vector of distance vectors. */
336 print_dist_vectors (FILE *outf, VEC (lambda_vector, heap) *dist_vects,
342 for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, v); j++)
343 print_lambda_vector (outf, v, length);
349 debug_data_dependence_relation (struct data_dependence_relation *ddr)
351 dump_data_dependence_relation (stderr, ddr);
354 /* Dump function for a DATA_DEPENDENCE_RELATION structure. */
357 dump_data_dependence_relation (FILE *outf,
358 struct data_dependence_relation *ddr)
360 struct data_reference *dra, *drb;
362 fprintf (outf, "(Data Dep: \n");
364 if (!ddr || DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
366 fprintf (outf, " (don't know)\n)\n");
372 dump_data_reference (outf, dra);
373 dump_data_reference (outf, drb);
375 if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
376 fprintf (outf, " (no dependence)\n");
378 else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
383 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
385 fprintf (outf, " access_fn_A: ");
386 print_generic_stmt (outf, DR_ACCESS_FN (dra, i), 0);
387 fprintf (outf, " access_fn_B: ");
388 print_generic_stmt (outf, DR_ACCESS_FN (drb, i), 0);
389 dump_subscript (outf, DDR_SUBSCRIPT (ddr, i));
392 fprintf (outf, " inner loop index: %d\n", DDR_INNER_LOOP (ddr));
393 fprintf (outf, " loop nest: (");
394 for (i = 0; VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
395 fprintf (outf, "%d ", loopi->num);
396 fprintf (outf, ")\n");
398 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
400 fprintf (outf, " distance_vector: ");
401 print_lambda_vector (outf, DDR_DIST_VECT (ddr, i),
405 for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++)
407 fprintf (outf, " direction_vector: ");
408 print_direction_vector (outf, DDR_DIR_VECT (ddr, i),
413 fprintf (outf, ")\n");
416 /* Dump function for a DATA_DEPENDENCE_DIRECTION structure. */
419 dump_data_dependence_direction (FILE *file,
420 enum data_dependence_direction dir)
436 case dir_positive_or_negative:
437 fprintf (file, "+-");
440 case dir_positive_or_equal:
441 fprintf (file, "+=");
444 case dir_negative_or_equal:
445 fprintf (file, "-=");
457 /* Dumps the distance and direction vectors in FILE. DDRS contains
458 the dependence relations, and VECT_SIZE is the size of the
459 dependence vectors, or in other words the number of loops in the
463 dump_dist_dir_vectors (FILE *file, VEC (ddr_p, heap) *ddrs)
466 struct data_dependence_relation *ddr;
469 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
470 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE && DDR_AFFINE_P (ddr))
472 for (j = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), j, v); j++)
474 fprintf (file, "DISTANCE_V (");
475 print_lambda_vector (file, v, DDR_NB_LOOPS (ddr));
476 fprintf (file, ")\n");
479 for (j = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), j, v); j++)
481 fprintf (file, "DIRECTION_V (");
482 print_direction_vector (file, v, DDR_NB_LOOPS (ddr));
483 fprintf (file, ")\n");
487 fprintf (file, "\n\n");
490 /* Dumps the data dependence relations DDRS in FILE. */
493 dump_ddrs (FILE *file, VEC (ddr_p, heap) *ddrs)
496 struct data_dependence_relation *ddr;
498 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
499 dump_data_dependence_relation (file, ddr);
501 fprintf (file, "\n\n");
504 /* Helper function for split_constant_offset. Expresses OP0 CODE OP1
505 (the type of the result is TYPE) as VAR + OFF, where OFF is a nonzero
506 constant of type ssizetype, and returns true. If we cannot do this
507 with OFF nonzero, OFF and VAR are set to NULL_TREE instead and false
511 split_constant_offset_1 (tree type, tree op0, enum tree_code code, tree op1,
512 tree *var, tree *off)
516 enum tree_code ocode = code;
524 *var = build_int_cst (type, 0);
525 *off = fold_convert (ssizetype, op0);
528 case POINTER_PLUS_EXPR:
533 split_constant_offset (op0, &var0, &off0);
534 split_constant_offset (op1, &var1, &off1);
535 *var = fold_build2 (code, type, var0, var1);
536 *off = size_binop (ocode, off0, off1);
540 if (TREE_CODE (op1) != INTEGER_CST)
543 split_constant_offset (op0, &var0, &off0);
544 *var = fold_build2 (MULT_EXPR, type, var0, op1);
545 *off = size_binop (MULT_EXPR, off0, fold_convert (ssizetype, op1));
551 HOST_WIDE_INT pbitsize, pbitpos;
552 enum machine_mode pmode;
553 int punsignedp, pvolatilep;
555 op0 = TREE_OPERAND (op0, 0);
556 if (!handled_component_p (op0))
559 base = get_inner_reference (op0, &pbitsize, &pbitpos, &poffset,
560 &pmode, &punsignedp, &pvolatilep, false);
562 if (pbitpos % BITS_PER_UNIT != 0)
564 base = build_fold_addr_expr (base);
565 off0 = ssize_int (pbitpos / BITS_PER_UNIT);
569 split_constant_offset (poffset, &poffset, &off1);
570 off0 = size_binop (PLUS_EXPR, off0, off1);
571 if (POINTER_TYPE_P (TREE_TYPE (base)))
572 base = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (base),
573 base, fold_convert (sizetype, poffset));
575 base = fold_build2 (PLUS_EXPR, TREE_TYPE (base), base,
576 fold_convert (TREE_TYPE (base), poffset));
579 var0 = fold_convert (type, base);
581 /* If variable length types are involved, punt, otherwise casts
582 might be converted into ARRAY_REFs in gimplify_conversion.
583 To compute that ARRAY_REF's element size TYPE_SIZE_UNIT, which
584 possibly no longer appears in current GIMPLE, might resurface.
585 This perhaps could run
586 if (CONVERT_EXPR_P (var0))
588 gimplify_conversion (&var0);
589 // Attempt to fill in any within var0 found ARRAY_REF's
590 // element size from corresponding op embedded ARRAY_REF,
591 // if unsuccessful, just punt.
593 while (POINTER_TYPE_P (type))
594 type = TREE_TYPE (type);
595 if (int_size_in_bytes (type) < 0)
605 gimple def_stmt = SSA_NAME_DEF_STMT (op0);
606 enum tree_code subcode;
608 if (gimple_code (def_stmt) != GIMPLE_ASSIGN)
611 var0 = gimple_assign_rhs1 (def_stmt);
612 subcode = gimple_assign_rhs_code (def_stmt);
613 var1 = gimple_assign_rhs2 (def_stmt);
615 return split_constant_offset_1 (type, var0, subcode, var1, var, off);
623 /* Expresses EXP as VAR + OFF, where off is a constant. The type of OFF
624 will be ssizetype. */
627 split_constant_offset (tree exp, tree *var, tree *off)
629 tree type = TREE_TYPE (exp), otype, op0, op1, e, o;
633 *off = ssize_int (0);
636 if (automatically_generated_chrec_p (exp))
639 otype = TREE_TYPE (exp);
640 code = TREE_CODE (exp);
641 extract_ops_from_tree (exp, &code, &op0, &op1);
642 if (split_constant_offset_1 (otype, op0, code, op1, &e, &o))
644 *var = fold_convert (type, e);
649 /* Returns the address ADDR of an object in a canonical shape (without nop
650 casts, and with type of pointer to the object). */
653 canonicalize_base_object_address (tree addr)
659 /* The base address may be obtained by casting from integer, in that case
661 if (!POINTER_TYPE_P (TREE_TYPE (addr)))
664 if (TREE_CODE (addr) != ADDR_EXPR)
667 return build_fold_addr_expr (TREE_OPERAND (addr, 0));
670 /* Analyzes the behavior of the memory reference DR in the innermost loop that
671 contains it. Returns true if analysis succeed or false otherwise. */
674 dr_analyze_innermost (struct data_reference *dr)
676 gimple stmt = DR_STMT (dr);
677 struct loop *loop = loop_containing_stmt (stmt);
678 tree ref = DR_REF (dr);
679 HOST_WIDE_INT pbitsize, pbitpos;
681 enum machine_mode pmode;
682 int punsignedp, pvolatilep;
683 affine_iv base_iv, offset_iv;
684 tree init, dinit, step;
686 if (dump_file && (dump_flags & TDF_DETAILS))
687 fprintf (dump_file, "analyze_innermost: ");
689 base = get_inner_reference (ref, &pbitsize, &pbitpos, &poffset,
690 &pmode, &punsignedp, &pvolatilep, false);
691 gcc_assert (base != NULL_TREE);
693 if (pbitpos % BITS_PER_UNIT != 0)
695 if (dump_file && (dump_flags & TDF_DETAILS))
696 fprintf (dump_file, "failed: bit offset alignment.\n");
700 base = build_fold_addr_expr (base);
701 if (!simple_iv (loop, stmt, base, &base_iv, false))
703 if (dump_file && (dump_flags & TDF_DETAILS))
704 fprintf (dump_file, "failed: evolution of base is not affine.\n");
709 offset_iv.base = ssize_int (0);
710 offset_iv.step = ssize_int (0);
712 else if (!simple_iv (loop, stmt, poffset, &offset_iv, false))
714 if (dump_file && (dump_flags & TDF_DETAILS))
715 fprintf (dump_file, "failed: evolution of offset is not affine.\n");
719 init = ssize_int (pbitpos / BITS_PER_UNIT);
720 split_constant_offset (base_iv.base, &base_iv.base, &dinit);
721 init = size_binop (PLUS_EXPR, init, dinit);
722 split_constant_offset (offset_iv.base, &offset_iv.base, &dinit);
723 init = size_binop (PLUS_EXPR, init, dinit);
725 step = size_binop (PLUS_EXPR,
726 fold_convert (ssizetype, base_iv.step),
727 fold_convert (ssizetype, offset_iv.step));
729 DR_BASE_ADDRESS (dr) = canonicalize_base_object_address (base_iv.base);
731 DR_OFFSET (dr) = fold_convert (ssizetype, offset_iv.base);
735 DR_ALIGNED_TO (dr) = size_int (highest_pow2_factor (offset_iv.base));
737 if (dump_file && (dump_flags & TDF_DETAILS))
738 fprintf (dump_file, "success.\n");
743 /* Determines the base object and the list of indices of memory reference
744 DR, analyzed in loop nest NEST. */
747 dr_analyze_indices (struct data_reference *dr, struct loop *nest)
749 gimple stmt = DR_STMT (dr);
750 struct loop *loop = loop_containing_stmt (stmt);
751 VEC (tree, heap) *access_fns = NULL;
752 tree ref = unshare_expr (DR_REF (dr)), aref = ref, op;
753 tree base, off, access_fn;
754 basic_block before_loop = block_before_loop (nest);
756 while (handled_component_p (aref))
758 if (TREE_CODE (aref) == ARRAY_REF)
760 op = TREE_OPERAND (aref, 1);
761 access_fn = analyze_scalar_evolution (loop, op);
762 access_fn = instantiate_scev (before_loop, loop, access_fn);
763 VEC_safe_push (tree, heap, access_fns, access_fn);
765 TREE_OPERAND (aref, 1) = build_int_cst (TREE_TYPE (op), 0);
768 aref = TREE_OPERAND (aref, 0);
771 if (INDIRECT_REF_P (aref))
773 op = TREE_OPERAND (aref, 0);
774 access_fn = analyze_scalar_evolution (loop, op);
775 access_fn = instantiate_scev (before_loop, loop, access_fn);
776 base = initial_condition (access_fn);
777 split_constant_offset (base, &base, &off);
778 access_fn = chrec_replace_initial_condition (access_fn,
779 fold_convert (TREE_TYPE (base), off));
781 TREE_OPERAND (aref, 0) = base;
782 VEC_safe_push (tree, heap, access_fns, access_fn);
785 DR_BASE_OBJECT (dr) = ref;
786 DR_ACCESS_FNS (dr) = access_fns;
789 /* Extracts the alias analysis information from the memory reference DR. */
792 dr_analyze_alias (struct data_reference *dr)
794 gimple stmt = DR_STMT (dr);
795 tree ref = DR_REF (dr);
796 tree base = get_base_address (ref), addr, smt = NULL_TREE;
803 else if (INDIRECT_REF_P (base))
805 addr = TREE_OPERAND (base, 0);
806 if (TREE_CODE (addr) == SSA_NAME)
808 smt = symbol_mem_tag (SSA_NAME_VAR (addr));
809 DR_PTR_INFO (dr) = SSA_NAME_PTR_INFO (addr);
813 DR_SYMBOL_TAG (dr) = smt;
815 vops = BITMAP_ALLOC (NULL);
816 FOR_EACH_SSA_TREE_OPERAND (op, stmt, it, SSA_OP_VIRTUAL_USES)
818 bitmap_set_bit (vops, DECL_UID (SSA_NAME_VAR (op)));
824 /* Returns true if the address of DR is invariant. */
827 dr_address_invariant_p (struct data_reference *dr)
832 for (i = 0; VEC_iterate (tree, DR_ACCESS_FNS (dr), i, idx); i++)
833 if (tree_contains_chrecs (idx, NULL))
839 /* Frees data reference DR. */
842 free_data_ref (data_reference_p dr)
844 BITMAP_FREE (DR_VOPS (dr));
845 VEC_free (tree, heap, DR_ACCESS_FNS (dr));
849 /* Analyzes memory reference MEMREF accessed in STMT. The reference
850 is read if IS_READ is true, write otherwise. Returns the
851 data_reference description of MEMREF. NEST is the outermost loop of the
852 loop nest in that the reference should be analyzed. */
854 struct data_reference *
855 create_data_ref (struct loop *nest, tree memref, gimple stmt, bool is_read)
857 struct data_reference *dr;
859 if (dump_file && (dump_flags & TDF_DETAILS))
861 fprintf (dump_file, "Creating dr for ");
862 print_generic_expr (dump_file, memref, TDF_SLIM);
863 fprintf (dump_file, "\n");
866 dr = XCNEW (struct data_reference);
868 DR_REF (dr) = memref;
869 DR_IS_READ (dr) = is_read;
871 dr_analyze_innermost (dr);
872 dr_analyze_indices (dr, nest);
873 dr_analyze_alias (dr);
875 if (dump_file && (dump_flags & TDF_DETAILS))
877 fprintf (dump_file, "\tbase_address: ");
878 print_generic_expr (dump_file, DR_BASE_ADDRESS (dr), TDF_SLIM);
879 fprintf (dump_file, "\n\toffset from base address: ");
880 print_generic_expr (dump_file, DR_OFFSET (dr), TDF_SLIM);
881 fprintf (dump_file, "\n\tconstant offset from base address: ");
882 print_generic_expr (dump_file, DR_INIT (dr), TDF_SLIM);
883 fprintf (dump_file, "\n\tstep: ");
884 print_generic_expr (dump_file, DR_STEP (dr), TDF_SLIM);
885 fprintf (dump_file, "\n\taligned to: ");
886 print_generic_expr (dump_file, DR_ALIGNED_TO (dr), TDF_SLIM);
887 fprintf (dump_file, "\n\tbase_object: ");
888 print_generic_expr (dump_file, DR_BASE_OBJECT (dr), TDF_SLIM);
889 fprintf (dump_file, "\n\tsymbol tag: ");
890 print_generic_expr (dump_file, DR_SYMBOL_TAG (dr), TDF_SLIM);
891 fprintf (dump_file, "\n");
897 /* Returns true if FNA == FNB. */
900 affine_function_equal_p (affine_fn fna, affine_fn fnb)
902 unsigned i, n = VEC_length (tree, fna);
904 if (n != VEC_length (tree, fnb))
907 for (i = 0; i < n; i++)
908 if (!operand_equal_p (VEC_index (tree, fna, i),
909 VEC_index (tree, fnb, i), 0))
915 /* If all the functions in CF are the same, returns one of them,
916 otherwise returns NULL. */
919 common_affine_function (conflict_function *cf)
924 if (!CF_NONTRIVIAL_P (cf))
929 for (i = 1; i < cf->n; i++)
930 if (!affine_function_equal_p (comm, cf->fns[i]))
936 /* Returns the base of the affine function FN. */
939 affine_function_base (affine_fn fn)
941 return VEC_index (tree, fn, 0);
944 /* Returns true if FN is a constant. */
947 affine_function_constant_p (affine_fn fn)
952 for (i = 1; VEC_iterate (tree, fn, i, coef); i++)
953 if (!integer_zerop (coef))
959 /* Returns true if FN is the zero constant function. */
962 affine_function_zero_p (affine_fn fn)
964 return (integer_zerop (affine_function_base (fn))
965 && affine_function_constant_p (fn));
968 /* Returns a signed integer type with the largest precision from TA
972 signed_type_for_types (tree ta, tree tb)
974 if (TYPE_PRECISION (ta) > TYPE_PRECISION (tb))
975 return signed_type_for (ta);
977 return signed_type_for (tb);
980 /* Applies operation OP on affine functions FNA and FNB, and returns the
984 affine_fn_op (enum tree_code op, affine_fn fna, affine_fn fnb)
990 if (VEC_length (tree, fnb) > VEC_length (tree, fna))
992 n = VEC_length (tree, fna);
993 m = VEC_length (tree, fnb);
997 n = VEC_length (tree, fnb);
998 m = VEC_length (tree, fna);
1001 ret = VEC_alloc (tree, heap, m);
1002 for (i = 0; i < n; i++)
1004 tree type = signed_type_for_types (TREE_TYPE (VEC_index (tree, fna, i)),
1005 TREE_TYPE (VEC_index (tree, fnb, i)));
1007 VEC_quick_push (tree, ret,
1008 fold_build2 (op, type,
1009 VEC_index (tree, fna, i),
1010 VEC_index (tree, fnb, i)));
1013 for (; VEC_iterate (tree, fna, i, coef); i++)
1014 VEC_quick_push (tree, ret,
1015 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1016 coef, integer_zero_node));
1017 for (; VEC_iterate (tree, fnb, i, coef); i++)
1018 VEC_quick_push (tree, ret,
1019 fold_build2 (op, signed_type_for (TREE_TYPE (coef)),
1020 integer_zero_node, coef));
1025 /* Returns the sum of affine functions FNA and FNB. */
1028 affine_fn_plus (affine_fn fna, affine_fn fnb)
1030 return affine_fn_op (PLUS_EXPR, fna, fnb);
1033 /* Returns the difference of affine functions FNA and FNB. */
1036 affine_fn_minus (affine_fn fna, affine_fn fnb)
1038 return affine_fn_op (MINUS_EXPR, fna, fnb);
1041 /* Frees affine function FN. */
1044 affine_fn_free (affine_fn fn)
1046 VEC_free (tree, heap, fn);
1049 /* Determine for each subscript in the data dependence relation DDR
1053 compute_subscript_distance (struct data_dependence_relation *ddr)
1055 conflict_function *cf_a, *cf_b;
1056 affine_fn fn_a, fn_b, diff;
1058 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
1062 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
1064 struct subscript *subscript;
1066 subscript = DDR_SUBSCRIPT (ddr, i);
1067 cf_a = SUB_CONFLICTS_IN_A (subscript);
1068 cf_b = SUB_CONFLICTS_IN_B (subscript);
1070 fn_a = common_affine_function (cf_a);
1071 fn_b = common_affine_function (cf_b);
1074 SUB_DISTANCE (subscript) = chrec_dont_know;
1077 diff = affine_fn_minus (fn_a, fn_b);
1079 if (affine_function_constant_p (diff))
1080 SUB_DISTANCE (subscript) = affine_function_base (diff);
1082 SUB_DISTANCE (subscript) = chrec_dont_know;
1084 affine_fn_free (diff);
1089 /* Returns the conflict function for "unknown". */
1091 static conflict_function *
1092 conflict_fn_not_known (void)
1094 conflict_function *fn = XCNEW (conflict_function);
1100 /* Returns the conflict function for "independent". */
1102 static conflict_function *
1103 conflict_fn_no_dependence (void)
1105 conflict_function *fn = XCNEW (conflict_function);
1106 fn->n = NO_DEPENDENCE;
1111 /* Returns true if the address of OBJ is invariant in LOOP. */
1114 object_address_invariant_in_loop_p (const struct loop *loop, const_tree obj)
1116 while (handled_component_p (obj))
1118 if (TREE_CODE (obj) == ARRAY_REF)
1120 /* Index of the ARRAY_REF was zeroed in analyze_indices, thus we only
1121 need to check the stride and the lower bound of the reference. */
1122 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1124 || chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 3),
1128 else if (TREE_CODE (obj) == COMPONENT_REF)
1130 if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2),
1134 obj = TREE_OPERAND (obj, 0);
1137 if (!INDIRECT_REF_P (obj))
1140 return !chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 0),
1144 /* Returns true if A and B are accesses to different objects, or to different
1145 fields of the same object. */
1148 disjoint_objects_p (tree a, tree b)
1150 tree base_a, base_b;
1151 VEC (tree, heap) *comp_a = NULL, *comp_b = NULL;
1154 base_a = get_base_address (a);
1155 base_b = get_base_address (b);
1159 && base_a != base_b)
1162 if (!operand_equal_p (base_a, base_b, 0))
1165 /* Compare the component references of A and B. We must start from the inner
1166 ones, so record them to the vector first. */
1167 while (handled_component_p (a))
1169 VEC_safe_push (tree, heap, comp_a, a);
1170 a = TREE_OPERAND (a, 0);
1172 while (handled_component_p (b))
1174 VEC_safe_push (tree, heap, comp_b, b);
1175 b = TREE_OPERAND (b, 0);
1181 if (VEC_length (tree, comp_a) == 0
1182 || VEC_length (tree, comp_b) == 0)
1185 a = VEC_pop (tree, comp_a);
1186 b = VEC_pop (tree, comp_b);
1188 /* Real and imaginary part of a variable do not alias. */
1189 if ((TREE_CODE (a) == REALPART_EXPR
1190 && TREE_CODE (b) == IMAGPART_EXPR)
1191 || (TREE_CODE (a) == IMAGPART_EXPR
1192 && TREE_CODE (b) == REALPART_EXPR))
1198 if (TREE_CODE (a) != TREE_CODE (b))
1201 /* Nothing to do for ARRAY_REFs, as the indices of array_refs in
1202 DR_BASE_OBJECT are always zero. */
1203 if (TREE_CODE (a) == ARRAY_REF)
1205 else if (TREE_CODE (a) == COMPONENT_REF)
1207 if (operand_equal_p (TREE_OPERAND (a, 1), TREE_OPERAND (b, 1), 0))
1210 /* Different fields of unions may overlap. */
1211 base_a = TREE_OPERAND (a, 0);
1212 if (TREE_CODE (TREE_TYPE (base_a)) == UNION_TYPE)
1215 /* Different fields of structures cannot. */
1223 VEC_free (tree, heap, comp_a);
1224 VEC_free (tree, heap, comp_b);
1229 /* Returns false if we can prove that data references A and B do not alias,
1233 dr_may_alias_p (const struct data_reference *a, const struct data_reference *b)
1235 const_tree addr_a = DR_BASE_ADDRESS (a);
1236 const_tree addr_b = DR_BASE_ADDRESS (b);
1237 const_tree type_a, type_b;
1238 const_tree decl_a = NULL_TREE, decl_b = NULL_TREE;
1240 /* If the sets of virtual operands are disjoint, the memory references do not
1242 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
1245 /* If the accessed objects are disjoint, the memory references do not
1247 if (disjoint_objects_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b)))
1250 if (!addr_a || !addr_b)
1253 /* If the references are based on different static objects, they cannot alias
1254 (PTA should be able to disambiguate such accesses, but often it fails to,
1255 since currently we cannot distinguish between pointer and offset in pointer
1257 if (TREE_CODE (addr_a) == ADDR_EXPR
1258 && TREE_CODE (addr_b) == ADDR_EXPR)
1259 return TREE_OPERAND (addr_a, 0) == TREE_OPERAND (addr_b, 0);
1261 /* An instruction writing through a restricted pointer is "independent" of any
1262 instruction reading or writing through a different restricted pointer,
1263 in the same block/scope. */
1265 type_a = TREE_TYPE (addr_a);
1266 type_b = TREE_TYPE (addr_b);
1267 gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b));
1269 if (TREE_CODE (addr_a) == SSA_NAME)
1270 decl_a = SSA_NAME_VAR (addr_a);
1271 if (TREE_CODE (addr_b) == SSA_NAME)
1272 decl_b = SSA_NAME_VAR (addr_b);
1274 if (TYPE_RESTRICT (type_a) && TYPE_RESTRICT (type_b)
1275 && (!DR_IS_READ (a) || !DR_IS_READ (b))
1276 && decl_a && DECL_P (decl_a)
1277 && decl_b && DECL_P (decl_b)
1279 && TREE_CODE (DECL_CONTEXT (decl_a)) == FUNCTION_DECL
1280 && DECL_CONTEXT (decl_a) == DECL_CONTEXT (decl_b))
1286 static void compute_self_dependence (struct data_dependence_relation *);
1288 /* Initialize a data dependence relation between data accesses A and
1289 B. NB_LOOPS is the number of loops surrounding the references: the
1290 size of the classic distance/direction vectors. */
1292 static struct data_dependence_relation *
1293 initialize_data_dependence_relation (struct data_reference *a,
1294 struct data_reference *b,
1295 VEC (loop_p, heap) *loop_nest)
1297 struct data_dependence_relation *res;
1300 res = XNEW (struct data_dependence_relation);
1303 DDR_LOOP_NEST (res) = NULL;
1304 DDR_REVERSED_P (res) = false;
1305 DDR_SUBSCRIPTS (res) = NULL;
1306 DDR_DIR_VECTS (res) = NULL;
1307 DDR_DIST_VECTS (res) = NULL;
1309 if (a == NULL || b == NULL)
1311 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1315 /* If the data references do not alias, then they are independent. */
1316 if (!dr_may_alias_p (a, b))
1318 DDR_ARE_DEPENDENT (res) = chrec_known;
1322 /* When the references are exactly the same, don't spend time doing
1323 the data dependence tests, just initialize the ddr and return. */
1324 if (operand_equal_p (DR_REF (a), DR_REF (b), 0))
1326 DDR_AFFINE_P (res) = true;
1327 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1328 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1329 DDR_LOOP_NEST (res) = loop_nest;
1330 DDR_INNER_LOOP (res) = 0;
1331 DDR_SELF_REFERENCE (res) = true;
1332 compute_self_dependence (res);
1336 /* If the references do not access the same object, we do not know
1337 whether they alias or not. */
1338 if (!operand_equal_p (DR_BASE_OBJECT (a), DR_BASE_OBJECT (b), 0))
1340 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1344 /* If the base of the object is not invariant in the loop nest, we cannot
1345 analyze it. TODO -- in fact, it would suffice to record that there may
1346 be arbitrary dependences in the loops where the base object varies. */
1347 if (!object_address_invariant_in_loop_p (VEC_index (loop_p, loop_nest, 0),
1348 DR_BASE_OBJECT (a)))
1350 DDR_ARE_DEPENDENT (res) = chrec_dont_know;
1354 gcc_assert (DR_NUM_DIMENSIONS (a) == DR_NUM_DIMENSIONS (b));
1356 DDR_AFFINE_P (res) = true;
1357 DDR_ARE_DEPENDENT (res) = NULL_TREE;
1358 DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a));
1359 DDR_LOOP_NEST (res) = loop_nest;
1360 DDR_INNER_LOOP (res) = 0;
1361 DDR_SELF_REFERENCE (res) = false;
1363 for (i = 0; i < DR_NUM_DIMENSIONS (a); i++)
1365 struct subscript *subscript;
1367 subscript = XNEW (struct subscript);
1368 SUB_CONFLICTS_IN_A (subscript) = conflict_fn_not_known ();
1369 SUB_CONFLICTS_IN_B (subscript) = conflict_fn_not_known ();
1370 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
1371 SUB_DISTANCE (subscript) = chrec_dont_know;
1372 VEC_safe_push (subscript_p, heap, DDR_SUBSCRIPTS (res), subscript);
1378 /* Frees memory used by the conflict function F. */
1381 free_conflict_function (conflict_function *f)
1385 if (CF_NONTRIVIAL_P (f))
1387 for (i = 0; i < f->n; i++)
1388 affine_fn_free (f->fns[i]);
1393 /* Frees memory used by SUBSCRIPTS. */
1396 free_subscripts (VEC (subscript_p, heap) *subscripts)
1401 for (i = 0; VEC_iterate (subscript_p, subscripts, i, s); i++)
1403 free_conflict_function (s->conflicting_iterations_in_a);
1404 free_conflict_function (s->conflicting_iterations_in_b);
1407 VEC_free (subscript_p, heap, subscripts);
1410 /* Set DDR_ARE_DEPENDENT to CHREC and finalize the subscript overlap
1414 finalize_ddr_dependent (struct data_dependence_relation *ddr,
1417 if (dump_file && (dump_flags & TDF_DETAILS))
1419 fprintf (dump_file, "(dependence classified: ");
1420 print_generic_expr (dump_file, chrec, 0);
1421 fprintf (dump_file, ")\n");
1424 DDR_ARE_DEPENDENT (ddr) = chrec;
1425 free_subscripts (DDR_SUBSCRIPTS (ddr));
1426 DDR_SUBSCRIPTS (ddr) = NULL;
1429 /* The dependence relation DDR cannot be represented by a distance
1433 non_affine_dependence_relation (struct data_dependence_relation *ddr)
1435 if (dump_file && (dump_flags & TDF_DETAILS))
1436 fprintf (dump_file, "(Dependence relation cannot be represented by distance vector.) \n");
1438 DDR_AFFINE_P (ddr) = false;
1443 /* This section contains the classic Banerjee tests. */
1445 /* Returns true iff CHREC_A and CHREC_B are not dependent on any index
1446 variables, i.e., if the ZIV (Zero Index Variable) test is true. */
1449 ziv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1451 return (evolution_function_is_constant_p (chrec_a)
1452 && evolution_function_is_constant_p (chrec_b));
1455 /* Returns true iff CHREC_A and CHREC_B are dependent on an index
1456 variable, i.e., if the SIV (Single Index Variable) test is true. */
1459 siv_subscript_p (const_tree chrec_a, const_tree chrec_b)
1461 if ((evolution_function_is_constant_p (chrec_a)
1462 && evolution_function_is_univariate_p (chrec_b))
1463 || (evolution_function_is_constant_p (chrec_b)
1464 && evolution_function_is_univariate_p (chrec_a)))
1467 if (evolution_function_is_univariate_p (chrec_a)
1468 && evolution_function_is_univariate_p (chrec_b))
1470 switch (TREE_CODE (chrec_a))
1472 case POLYNOMIAL_CHREC:
1473 switch (TREE_CODE (chrec_b))
1475 case POLYNOMIAL_CHREC:
1476 if (CHREC_VARIABLE (chrec_a) != CHREC_VARIABLE (chrec_b))
1491 /* Creates a conflict function with N dimensions. The affine functions
1492 in each dimension follow. */
1494 static conflict_function *
1495 conflict_fn (unsigned n, ...)
1498 conflict_function *ret = XCNEW (conflict_function);
1501 gcc_assert (0 < n && n <= MAX_DIM);
1505 for (i = 0; i < n; i++)
1506 ret->fns[i] = va_arg (ap, affine_fn);
1512 /* Returns constant affine function with value CST. */
1515 affine_fn_cst (tree cst)
1517 affine_fn fn = VEC_alloc (tree, heap, 1);
1518 VEC_quick_push (tree, fn, cst);
1522 /* Returns affine function with single variable, CST + COEF * x_DIM. */
1525 affine_fn_univar (tree cst, unsigned dim, tree coef)
1527 affine_fn fn = VEC_alloc (tree, heap, dim + 1);
1530 gcc_assert (dim > 0);
1531 VEC_quick_push (tree, fn, cst);
1532 for (i = 1; i < dim; i++)
1533 VEC_quick_push (tree, fn, integer_zero_node);
1534 VEC_quick_push (tree, fn, coef);
1538 /* Analyze a ZIV (Zero Index Variable) subscript. *OVERLAPS_A and
1539 *OVERLAPS_B are initialized to the functions that describe the
1540 relation between the elements accessed twice by CHREC_A and
1541 CHREC_B. For k >= 0, the following property is verified:
1543 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1546 analyze_ziv_subscript (tree chrec_a,
1548 conflict_function **overlaps_a,
1549 conflict_function **overlaps_b,
1550 tree *last_conflicts)
1552 tree type, difference;
1553 dependence_stats.num_ziv++;
1555 if (dump_file && (dump_flags & TDF_DETAILS))
1556 fprintf (dump_file, "(analyze_ziv_subscript \n");
1558 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1559 chrec_a = chrec_convert (type, chrec_a, NULL);
1560 chrec_b = chrec_convert (type, chrec_b, NULL);
1561 difference = chrec_fold_minus (type, chrec_a, chrec_b);
1563 switch (TREE_CODE (difference))
1566 if (integer_zerop (difference))
1568 /* The difference is equal to zero: the accessed index
1569 overlaps for each iteration in the loop. */
1570 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1571 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
1572 *last_conflicts = chrec_dont_know;
1573 dependence_stats.num_ziv_dependent++;
1577 /* The accesses do not overlap. */
1578 *overlaps_a = conflict_fn_no_dependence ();
1579 *overlaps_b = conflict_fn_no_dependence ();
1580 *last_conflicts = integer_zero_node;
1581 dependence_stats.num_ziv_independent++;
1586 /* We're not sure whether the indexes overlap. For the moment,
1587 conservatively answer "don't know". */
1588 if (dump_file && (dump_flags & TDF_DETAILS))
1589 fprintf (dump_file, "ziv test failed: difference is non-integer.\n");
1591 *overlaps_a = conflict_fn_not_known ();
1592 *overlaps_b = conflict_fn_not_known ();
1593 *last_conflicts = chrec_dont_know;
1594 dependence_stats.num_ziv_unimplemented++;
1598 if (dump_file && (dump_flags & TDF_DETAILS))
1599 fprintf (dump_file, ")\n");
1602 /* Sets NIT to the estimated number of executions of the statements in
1603 LOOP. If CONSERVATIVE is true, we must be sure that NIT is at least as
1604 large as the number of iterations. If we have no reliable estimate,
1605 the function returns false, otherwise returns true. */
1608 estimated_loop_iterations (struct loop *loop, bool conservative,
1611 estimate_numbers_of_iterations_loop (loop);
1614 if (!loop->any_upper_bound)
1617 *nit = loop->nb_iterations_upper_bound;
1621 if (!loop->any_estimate)
1624 *nit = loop->nb_iterations_estimate;
1630 /* Similar to estimated_loop_iterations, but returns the estimate only
1631 if it fits to HOST_WIDE_INT. If this is not the case, or the estimate
1632 on the number of iterations of LOOP could not be derived, returns -1. */
1635 estimated_loop_iterations_int (struct loop *loop, bool conservative)
1638 HOST_WIDE_INT hwi_nit;
1640 if (!estimated_loop_iterations (loop, conservative, &nit))
1643 if (!double_int_fits_in_shwi_p (nit))
1645 hwi_nit = double_int_to_shwi (nit);
1647 return hwi_nit < 0 ? -1 : hwi_nit;
1650 /* Similar to estimated_loop_iterations, but returns the estimate as a tree,
1651 and only if it fits to the int type. If this is not the case, or the
1652 estimate on the number of iterations of LOOP could not be derived, returns
1656 estimated_loop_iterations_tree (struct loop *loop, bool conservative)
1661 if (!estimated_loop_iterations (loop, conservative, &nit))
1662 return chrec_dont_know;
1664 type = lang_hooks.types.type_for_size (INT_TYPE_SIZE, true);
1665 if (!double_int_fits_to_tree_p (type, nit))
1666 return chrec_dont_know;
1668 return double_int_to_tree (type, nit);
1671 /* Analyze a SIV (Single Index Variable) subscript where CHREC_A is a
1672 constant, and CHREC_B is an affine function. *OVERLAPS_A and
1673 *OVERLAPS_B are initialized to the functions that describe the
1674 relation between the elements accessed twice by CHREC_A and
1675 CHREC_B. For k >= 0, the following property is verified:
1677 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
1680 analyze_siv_subscript_cst_affine (tree chrec_a,
1682 conflict_function **overlaps_a,
1683 conflict_function **overlaps_b,
1684 tree *last_conflicts)
1686 bool value0, value1, value2;
1687 tree type, difference, tmp;
1689 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
1690 chrec_a = chrec_convert (type, chrec_a, NULL);
1691 chrec_b = chrec_convert (type, chrec_b, NULL);
1692 difference = chrec_fold_minus (type, initial_condition (chrec_b), chrec_a);
1694 if (!chrec_is_positive (initial_condition (difference), &value0))
1696 if (dump_file && (dump_flags & TDF_DETAILS))
1697 fprintf (dump_file, "siv test failed: chrec is not positive.\n");
1699 dependence_stats.num_siv_unimplemented++;
1700 *overlaps_a = conflict_fn_not_known ();
1701 *overlaps_b = conflict_fn_not_known ();
1702 *last_conflicts = chrec_dont_know;
1707 if (value0 == false)
1709 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value1))
1711 if (dump_file && (dump_flags & TDF_DETAILS))
1712 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1714 *overlaps_a = conflict_fn_not_known ();
1715 *overlaps_b = conflict_fn_not_known ();
1716 *last_conflicts = chrec_dont_know;
1717 dependence_stats.num_siv_unimplemented++;
1726 chrec_b = {10, +, 1}
1729 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1731 HOST_WIDE_INT numiter;
1732 struct loop *loop = get_chrec_loop (chrec_b);
1734 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1735 tmp = fold_build2 (EXACT_DIV_EXPR, type,
1736 fold_build1 (ABS_EXPR, type, difference),
1737 CHREC_RIGHT (chrec_b));
1738 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1739 *last_conflicts = integer_one_node;
1742 /* Perform weak-zero siv test to see if overlap is
1743 outside the loop bounds. */
1744 numiter = estimated_loop_iterations_int (loop, false);
1747 && compare_tree_int (tmp, numiter) > 0)
1749 free_conflict_function (*overlaps_a);
1750 free_conflict_function (*overlaps_b);
1751 *overlaps_a = conflict_fn_no_dependence ();
1752 *overlaps_b = conflict_fn_no_dependence ();
1753 *last_conflicts = integer_zero_node;
1754 dependence_stats.num_siv_independent++;
1757 dependence_stats.num_siv_dependent++;
1761 /* When the step does not divide the difference, there are
1765 *overlaps_a = conflict_fn_no_dependence ();
1766 *overlaps_b = conflict_fn_no_dependence ();
1767 *last_conflicts = integer_zero_node;
1768 dependence_stats.num_siv_independent++;
1777 chrec_b = {10, +, -1}
1779 In this case, chrec_a will not overlap with chrec_b. */
1780 *overlaps_a = conflict_fn_no_dependence ();
1781 *overlaps_b = conflict_fn_no_dependence ();
1782 *last_conflicts = integer_zero_node;
1783 dependence_stats.num_siv_independent++;
1790 if (!chrec_is_positive (CHREC_RIGHT (chrec_b), &value2))
1792 if (dump_file && (dump_flags & TDF_DETAILS))
1793 fprintf (dump_file, "siv test failed: chrec not positive.\n");
1795 *overlaps_a = conflict_fn_not_known ();
1796 *overlaps_b = conflict_fn_not_known ();
1797 *last_conflicts = chrec_dont_know;
1798 dependence_stats.num_siv_unimplemented++;
1803 if (value2 == false)
1807 chrec_b = {10, +, -1}
1809 if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference))
1811 HOST_WIDE_INT numiter;
1812 struct loop *loop = get_chrec_loop (chrec_b);
1814 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
1815 tmp = fold_build2 (EXACT_DIV_EXPR, type, difference,
1816 CHREC_RIGHT (chrec_b));
1817 *overlaps_b = conflict_fn (1, affine_fn_cst (tmp));
1818 *last_conflicts = integer_one_node;
1820 /* Perform weak-zero siv test to see if overlap is
1821 outside the loop bounds. */
1822 numiter = estimated_loop_iterations_int (loop, false);
1825 && compare_tree_int (tmp, numiter) > 0)
1827 free_conflict_function (*overlaps_a);
1828 free_conflict_function (*overlaps_b);
1829 *overlaps_a = conflict_fn_no_dependence ();
1830 *overlaps_b = conflict_fn_no_dependence ();
1831 *last_conflicts = integer_zero_node;
1832 dependence_stats.num_siv_independent++;
1835 dependence_stats.num_siv_dependent++;
1839 /* When the step does not divide the difference, there
1843 *overlaps_a = conflict_fn_no_dependence ();
1844 *overlaps_b = conflict_fn_no_dependence ();
1845 *last_conflicts = integer_zero_node;
1846 dependence_stats.num_siv_independent++;
1856 In this case, chrec_a will not overlap with chrec_b. */
1857 *overlaps_a = conflict_fn_no_dependence ();
1858 *overlaps_b = conflict_fn_no_dependence ();
1859 *last_conflicts = integer_zero_node;
1860 dependence_stats.num_siv_independent++;
1868 /* Helper recursive function for initializing the matrix A. Returns
1869 the initial value of CHREC. */
1872 initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
1876 switch (TREE_CODE (chrec))
1878 case POLYNOMIAL_CHREC:
1879 gcc_assert (TREE_CODE (CHREC_RIGHT (chrec)) == INTEGER_CST);
1881 A[index][0] = mult * int_cst_value (CHREC_RIGHT (chrec));
1882 return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult);
1888 tree op0 = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1889 tree op1 = initialize_matrix_A (A, TREE_OPERAND (chrec, 1), index, mult);
1891 return chrec_fold_op (TREE_CODE (chrec), chrec_type (chrec), op0, op1);
1896 tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1897 return chrec_convert (chrec_type (chrec), op, NULL);
1902 /* Handle ~X as -1 - X. */
1903 tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult);
1904 return chrec_fold_op (MINUS_EXPR, chrec_type (chrec),
1905 build_int_cst (TREE_TYPE (chrec), -1), op);
1917 #define FLOOR_DIV(x,y) ((x) / (y))
1919 /* Solves the special case of the Diophantine equation:
1920 | {0, +, STEP_A}_x (OVERLAPS_A) = {0, +, STEP_B}_y (OVERLAPS_B)
1922 Computes the descriptions OVERLAPS_A and OVERLAPS_B. NITER is the
1923 number of iterations that loops X and Y run. The overlaps will be
1924 constructed as evolutions in dimension DIM. */
1927 compute_overlap_steps_for_affine_univar (int niter, int step_a, int step_b,
1928 affine_fn *overlaps_a,
1929 affine_fn *overlaps_b,
1930 tree *last_conflicts, int dim)
1932 if (((step_a > 0 && step_b > 0)
1933 || (step_a < 0 && step_b < 0)))
1935 int step_overlaps_a, step_overlaps_b;
1936 int gcd_steps_a_b, last_conflict, tau2;
1938 gcd_steps_a_b = gcd (step_a, step_b);
1939 step_overlaps_a = step_b / gcd_steps_a_b;
1940 step_overlaps_b = step_a / gcd_steps_a_b;
1944 tau2 = FLOOR_DIV (niter, step_overlaps_a);
1945 tau2 = MIN (tau2, FLOOR_DIV (niter, step_overlaps_b));
1946 last_conflict = tau2;
1947 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
1950 *last_conflicts = chrec_dont_know;
1952 *overlaps_a = affine_fn_univar (integer_zero_node, dim,
1953 build_int_cst (NULL_TREE,
1955 *overlaps_b = affine_fn_univar (integer_zero_node, dim,
1956 build_int_cst (NULL_TREE,
1962 *overlaps_a = affine_fn_cst (integer_zero_node);
1963 *overlaps_b = affine_fn_cst (integer_zero_node);
1964 *last_conflicts = integer_zero_node;
1968 /* Solves the special case of a Diophantine equation where CHREC_A is
1969 an affine bivariate function, and CHREC_B is an affine univariate
1970 function. For example,
1972 | {{0, +, 1}_x, +, 1335}_y = {0, +, 1336}_z
1974 has the following overlapping functions:
1976 | x (t, u, v) = {{0, +, 1336}_t, +, 1}_v
1977 | y (t, u, v) = {{0, +, 1336}_u, +, 1}_v
1978 | z (t, u, v) = {{{0, +, 1}_t, +, 1335}_u, +, 1}_v
1980 FORNOW: This is a specialized implementation for a case occurring in
1981 a common benchmark. Implement the general algorithm. */
1984 compute_overlap_steps_for_affine_1_2 (tree chrec_a, tree chrec_b,
1985 conflict_function **overlaps_a,
1986 conflict_function **overlaps_b,
1987 tree *last_conflicts)
1989 bool xz_p, yz_p, xyz_p;
1990 int step_x, step_y, step_z;
1991 HOST_WIDE_INT niter_x, niter_y, niter_z, niter;
1992 affine_fn overlaps_a_xz, overlaps_b_xz;
1993 affine_fn overlaps_a_yz, overlaps_b_yz;
1994 affine_fn overlaps_a_xyz, overlaps_b_xyz;
1995 affine_fn ova1, ova2, ovb;
1996 tree last_conflicts_xz, last_conflicts_yz, last_conflicts_xyz;
1998 step_x = int_cst_value (CHREC_RIGHT (CHREC_LEFT (chrec_a)));
1999 step_y = int_cst_value (CHREC_RIGHT (chrec_a));
2000 step_z = int_cst_value (CHREC_RIGHT (chrec_b));
2003 estimated_loop_iterations_int (get_chrec_loop (CHREC_LEFT (chrec_a)),
2005 niter_y = estimated_loop_iterations_int (get_chrec_loop (chrec_a), false);
2006 niter_z = estimated_loop_iterations_int (get_chrec_loop (chrec_b), false);
2008 if (niter_x < 0 || niter_y < 0 || niter_z < 0)
2010 if (dump_file && (dump_flags & TDF_DETAILS))
2011 fprintf (dump_file, "overlap steps test failed: no iteration counts.\n");
2013 *overlaps_a = conflict_fn_not_known ();
2014 *overlaps_b = conflict_fn_not_known ();
2015 *last_conflicts = chrec_dont_know;
2019 niter = MIN (niter_x, niter_z);
2020 compute_overlap_steps_for_affine_univar (niter, step_x, step_z,
2023 &last_conflicts_xz, 1);
2024 niter = MIN (niter_y, niter_z);
2025 compute_overlap_steps_for_affine_univar (niter, step_y, step_z,
2028 &last_conflicts_yz, 2);
2029 niter = MIN (niter_x, niter_z);
2030 niter = MIN (niter_y, niter);
2031 compute_overlap_steps_for_affine_univar (niter, step_x + step_y, step_z,
2034 &last_conflicts_xyz, 3);
2036 xz_p = !integer_zerop (last_conflicts_xz);
2037 yz_p = !integer_zerop (last_conflicts_yz);
2038 xyz_p = !integer_zerop (last_conflicts_xyz);
2040 if (xz_p || yz_p || xyz_p)
2042 ova1 = affine_fn_cst (integer_zero_node);
2043 ova2 = affine_fn_cst (integer_zero_node);
2044 ovb = affine_fn_cst (integer_zero_node);
2047 affine_fn t0 = ova1;
2050 ova1 = affine_fn_plus (ova1, overlaps_a_xz);
2051 ovb = affine_fn_plus (ovb, overlaps_b_xz);
2052 affine_fn_free (t0);
2053 affine_fn_free (t2);
2054 *last_conflicts = last_conflicts_xz;
2058 affine_fn t0 = ova2;
2061 ova2 = affine_fn_plus (ova2, overlaps_a_yz);
2062 ovb = affine_fn_plus (ovb, overlaps_b_yz);
2063 affine_fn_free (t0);
2064 affine_fn_free (t2);
2065 *last_conflicts = last_conflicts_yz;
2069 affine_fn t0 = ova1;
2070 affine_fn t2 = ova2;
2073 ova1 = affine_fn_plus (ova1, overlaps_a_xyz);
2074 ova2 = affine_fn_plus (ova2, overlaps_a_xyz);
2075 ovb = affine_fn_plus (ovb, overlaps_b_xyz);
2076 affine_fn_free (t0);
2077 affine_fn_free (t2);
2078 affine_fn_free (t4);
2079 *last_conflicts = last_conflicts_xyz;
2081 *overlaps_a = conflict_fn (2, ova1, ova2);
2082 *overlaps_b = conflict_fn (1, ovb);
2086 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2087 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2088 *last_conflicts = integer_zero_node;
2091 affine_fn_free (overlaps_a_xz);
2092 affine_fn_free (overlaps_b_xz);
2093 affine_fn_free (overlaps_a_yz);
2094 affine_fn_free (overlaps_b_yz);
2095 affine_fn_free (overlaps_a_xyz);
2096 affine_fn_free (overlaps_b_xyz);
2099 /* Determines the overlapping elements due to accesses CHREC_A and
2100 CHREC_B, that are affine functions. This function cannot handle
2101 symbolic evolution functions, ie. when initial conditions are
2102 parameters, because it uses lambda matrices of integers. */
2105 analyze_subscript_affine_affine (tree chrec_a,
2107 conflict_function **overlaps_a,
2108 conflict_function **overlaps_b,
2109 tree *last_conflicts)
2111 unsigned nb_vars_a, nb_vars_b, dim;
2112 HOST_WIDE_INT init_a, init_b, gamma, gcd_alpha_beta;
2113 lambda_matrix A, U, S;
2115 if (eq_evolutions_p (chrec_a, chrec_b))
2117 /* The accessed index overlaps for each iteration in the
2119 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2120 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2121 *last_conflicts = chrec_dont_know;
2124 if (dump_file && (dump_flags & TDF_DETAILS))
2125 fprintf (dump_file, "(analyze_subscript_affine_affine \n");
2127 /* For determining the initial intersection, we have to solve a
2128 Diophantine equation. This is the most time consuming part.
2130 For answering to the question: "Is there a dependence?" we have
2131 to prove that there exists a solution to the Diophantine
2132 equation, and that the solution is in the iteration domain,
2133 i.e. the solution is positive or zero, and that the solution
2134 happens before the upper bound loop.nb_iterations. Otherwise
2135 there is no dependence. This function outputs a description of
2136 the iterations that hold the intersections. */
2138 nb_vars_a = nb_vars_in_chrec (chrec_a);
2139 nb_vars_b = nb_vars_in_chrec (chrec_b);
2141 dim = nb_vars_a + nb_vars_b;
2142 U = lambda_matrix_new (dim, dim);
2143 A = lambda_matrix_new (dim, 1);
2144 S = lambda_matrix_new (dim, 1);
2146 init_a = int_cst_value (initialize_matrix_A (A, chrec_a, 0, 1));
2147 init_b = int_cst_value (initialize_matrix_A (A, chrec_b, nb_vars_a, -1));
2148 gamma = init_b - init_a;
2150 /* Don't do all the hard work of solving the Diophantine equation
2151 when we already know the solution: for example,
2154 | gamma = 3 - 3 = 0.
2155 Then the first overlap occurs during the first iterations:
2156 | {3, +, 1}_1 ({0, +, 4}_x) = {3, +, 4}_2 ({0, +, 1}_x)
2160 if (nb_vars_a == 1 && nb_vars_b == 1)
2162 HOST_WIDE_INT step_a, step_b;
2163 HOST_WIDE_INT niter, niter_a, niter_b;
2166 niter_a = estimated_loop_iterations_int (get_chrec_loop (chrec_a),
2168 niter_b = estimated_loop_iterations_int (get_chrec_loop (chrec_b),
2170 niter = MIN (niter_a, niter_b);
2171 step_a = int_cst_value (CHREC_RIGHT (chrec_a));
2172 step_b = int_cst_value (CHREC_RIGHT (chrec_b));
2174 compute_overlap_steps_for_affine_univar (niter, step_a, step_b,
2177 *overlaps_a = conflict_fn (1, ova);
2178 *overlaps_b = conflict_fn (1, ovb);
2181 else if (nb_vars_a == 2 && nb_vars_b == 1)
2182 compute_overlap_steps_for_affine_1_2
2183 (chrec_a, chrec_b, overlaps_a, overlaps_b, last_conflicts);
2185 else if (nb_vars_a == 1 && nb_vars_b == 2)
2186 compute_overlap_steps_for_affine_1_2
2187 (chrec_b, chrec_a, overlaps_b, overlaps_a, last_conflicts);
2191 if (dump_file && (dump_flags & TDF_DETAILS))
2192 fprintf (dump_file, "affine-affine test failed: too many variables.\n");
2193 *overlaps_a = conflict_fn_not_known ();
2194 *overlaps_b = conflict_fn_not_known ();
2195 *last_conflicts = chrec_dont_know;
2197 goto end_analyze_subs_aa;
2201 lambda_matrix_right_hermite (A, dim, 1, S, U);
2206 lambda_matrix_row_negate (U, dim, 0);
2208 gcd_alpha_beta = S[0][0];
2210 /* Something went wrong: for example in {1, +, 0}_5 vs. {0, +, 0}_5,
2211 but that is a quite strange case. Instead of ICEing, answer
2213 if (gcd_alpha_beta == 0)
2215 *overlaps_a = conflict_fn_not_known ();
2216 *overlaps_b = conflict_fn_not_known ();
2217 *last_conflicts = chrec_dont_know;
2218 goto end_analyze_subs_aa;
2221 /* The classic "gcd-test". */
2222 if (!int_divides_p (gcd_alpha_beta, gamma))
2224 /* The "gcd-test" has determined that there is no integer
2225 solution, i.e. there is no dependence. */
2226 *overlaps_a = conflict_fn_no_dependence ();
2227 *overlaps_b = conflict_fn_no_dependence ();
2228 *last_conflicts = integer_zero_node;
2231 /* Both access functions are univariate. This includes SIV and MIV cases. */
2232 else if (nb_vars_a == 1 && nb_vars_b == 1)
2234 /* Both functions should have the same evolution sign. */
2235 if (((A[0][0] > 0 && -A[1][0] > 0)
2236 || (A[0][0] < 0 && -A[1][0] < 0)))
2238 /* The solutions are given by:
2240 | [GAMMA/GCD_ALPHA_BETA t].[u11 u12] = [x0]
2243 For a given integer t. Using the following variables,
2245 | i0 = u11 * gamma / gcd_alpha_beta
2246 | j0 = u12 * gamma / gcd_alpha_beta
2253 | y0 = j0 + j1 * t. */
2254 HOST_WIDE_INT i0, j0, i1, j1;
2256 i0 = U[0][0] * gamma / gcd_alpha_beta;
2257 j0 = U[0][1] * gamma / gcd_alpha_beta;
2261 if ((i1 == 0 && i0 < 0)
2262 || (j1 == 0 && j0 < 0))
2264 /* There is no solution.
2265 FIXME: The case "i0 > nb_iterations, j0 > nb_iterations"
2266 falls in here, but for the moment we don't look at the
2267 upper bound of the iteration domain. */
2268 *overlaps_a = conflict_fn_no_dependence ();
2269 *overlaps_b = conflict_fn_no_dependence ();
2270 *last_conflicts = integer_zero_node;
2271 goto end_analyze_subs_aa;
2274 if (i1 > 0 && j1 > 0)
2276 HOST_WIDE_INT niter_a = estimated_loop_iterations_int
2277 (get_chrec_loop (chrec_a), false);
2278 HOST_WIDE_INT niter_b = estimated_loop_iterations_int
2279 (get_chrec_loop (chrec_b), false);
2280 HOST_WIDE_INT niter = MIN (niter_a, niter_b);
2282 /* (X0, Y0) is a solution of the Diophantine equation:
2283 "chrec_a (X0) = chrec_b (Y0)". */
2284 HOST_WIDE_INT tau1 = MAX (CEIL (-i0, i1),
2286 HOST_WIDE_INT x0 = i1 * tau1 + i0;
2287 HOST_WIDE_INT y0 = j1 * tau1 + j0;
2289 /* (X1, Y1) is the smallest positive solution of the eq
2290 "chrec_a (X1) = chrec_b (Y1)", i.e. this is where the
2291 first conflict occurs. */
2292 HOST_WIDE_INT min_multiple = MIN (x0 / i1, y0 / j1);
2293 HOST_WIDE_INT x1 = x0 - i1 * min_multiple;
2294 HOST_WIDE_INT y1 = y0 - j1 * min_multiple;
2298 HOST_WIDE_INT tau2 = MIN (FLOOR_DIV (niter - i0, i1),
2299 FLOOR_DIV (niter - j0, j1));
2300 HOST_WIDE_INT last_conflict = tau2 - (x1 - i0)/i1;
2302 /* If the overlap occurs outside of the bounds of the
2303 loop, there is no dependence. */
2304 if (x1 > niter || y1 > niter)
2306 *overlaps_a = conflict_fn_no_dependence ();
2307 *overlaps_b = conflict_fn_no_dependence ();
2308 *last_conflicts = integer_zero_node;
2309 goto end_analyze_subs_aa;
2312 *last_conflicts = build_int_cst (NULL_TREE, last_conflict);
2315 *last_conflicts = chrec_dont_know;
2319 affine_fn_univar (build_int_cst (NULL_TREE, x1),
2321 build_int_cst (NULL_TREE, i1)));
2324 affine_fn_univar (build_int_cst (NULL_TREE, y1),
2326 build_int_cst (NULL_TREE, j1)));
2330 /* FIXME: For the moment, the upper bound of the
2331 iteration domain for i and j is not checked. */
2332 if (dump_file && (dump_flags & TDF_DETAILS))
2333 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2334 *overlaps_a = conflict_fn_not_known ();
2335 *overlaps_b = conflict_fn_not_known ();
2336 *last_conflicts = chrec_dont_know;
2341 if (dump_file && (dump_flags & TDF_DETAILS))
2342 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2343 *overlaps_a = conflict_fn_not_known ();
2344 *overlaps_b = conflict_fn_not_known ();
2345 *last_conflicts = chrec_dont_know;
2350 if (dump_file && (dump_flags & TDF_DETAILS))
2351 fprintf (dump_file, "affine-affine test failed: unimplemented.\n");
2352 *overlaps_a = conflict_fn_not_known ();
2353 *overlaps_b = conflict_fn_not_known ();
2354 *last_conflicts = chrec_dont_know;
2357 end_analyze_subs_aa:
2358 if (dump_file && (dump_flags & TDF_DETAILS))
2360 fprintf (dump_file, " (overlaps_a = ");
2361 dump_conflict_function (dump_file, *overlaps_a);
2362 fprintf (dump_file, ")\n (overlaps_b = ");
2363 dump_conflict_function (dump_file, *overlaps_b);
2364 fprintf (dump_file, ")\n");
2365 fprintf (dump_file, ")\n");
2369 /* Returns true when analyze_subscript_affine_affine can be used for
2370 determining the dependence relation between chrec_a and chrec_b,
2371 that contain symbols. This function modifies chrec_a and chrec_b
2372 such that the analysis result is the same, and such that they don't
2373 contain symbols, and then can safely be passed to the analyzer.
2375 Example: The analysis of the following tuples of evolutions produce
2376 the same results: {x+1, +, 1}_1 vs. {x+3, +, 1}_1, and {-2, +, 1}_1
2379 {x+1, +, 1}_1 ({2, +, 1}_1) = {x+3, +, 1}_1 ({0, +, 1}_1)
2380 {-2, +, 1}_1 ({2, +, 1}_1) = {0, +, 1}_1 ({0, +, 1}_1)
2384 can_use_analyze_subscript_affine_affine (tree *chrec_a, tree *chrec_b)
2386 tree diff, type, left_a, left_b, right_b;
2388 if (chrec_contains_symbols (CHREC_RIGHT (*chrec_a))
2389 || chrec_contains_symbols (CHREC_RIGHT (*chrec_b)))
2390 /* FIXME: For the moment not handled. Might be refined later. */
2393 type = chrec_type (*chrec_a);
2394 left_a = CHREC_LEFT (*chrec_a);
2395 left_b = chrec_convert (type, CHREC_LEFT (*chrec_b), NULL);
2396 diff = chrec_fold_minus (type, left_a, left_b);
2398 if (!evolution_function_is_constant_p (diff))
2401 if (dump_file && (dump_flags & TDF_DETAILS))
2402 fprintf (dump_file, "can_use_subscript_aff_aff_for_symbolic \n");
2404 *chrec_a = build_polynomial_chrec (CHREC_VARIABLE (*chrec_a),
2405 diff, CHREC_RIGHT (*chrec_a));
2406 right_b = chrec_convert (type, CHREC_RIGHT (*chrec_b), NULL);
2407 *chrec_b = build_polynomial_chrec (CHREC_VARIABLE (*chrec_b),
2408 build_int_cst (type, 0),
2413 /* Analyze a SIV (Single Index Variable) subscript. *OVERLAPS_A and
2414 *OVERLAPS_B are initialized to the functions that describe the
2415 relation between the elements accessed twice by CHREC_A and
2416 CHREC_B. For k >= 0, the following property is verified:
2418 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2421 analyze_siv_subscript (tree chrec_a,
2423 conflict_function **overlaps_a,
2424 conflict_function **overlaps_b,
2425 tree *last_conflicts,
2428 dependence_stats.num_siv++;
2430 if (dump_file && (dump_flags & TDF_DETAILS))
2431 fprintf (dump_file, "(analyze_siv_subscript \n");
2433 if (evolution_function_is_constant_p (chrec_a)
2434 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2435 analyze_siv_subscript_cst_affine (chrec_a, chrec_b,
2436 overlaps_a, overlaps_b, last_conflicts);
2438 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2439 && evolution_function_is_constant_p (chrec_b))
2440 analyze_siv_subscript_cst_affine (chrec_b, chrec_a,
2441 overlaps_b, overlaps_a, last_conflicts);
2443 else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num)
2444 && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num))
2446 if (!chrec_contains_symbols (chrec_a)
2447 && !chrec_contains_symbols (chrec_b))
2449 analyze_subscript_affine_affine (chrec_a, chrec_b,
2450 overlaps_a, overlaps_b,
2453 if (CF_NOT_KNOWN_P (*overlaps_a)
2454 || CF_NOT_KNOWN_P (*overlaps_b))
2455 dependence_stats.num_siv_unimplemented++;
2456 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2457 || CF_NO_DEPENDENCE_P (*overlaps_b))
2458 dependence_stats.num_siv_independent++;
2460 dependence_stats.num_siv_dependent++;
2462 else if (can_use_analyze_subscript_affine_affine (&chrec_a,
2465 analyze_subscript_affine_affine (chrec_a, chrec_b,
2466 overlaps_a, overlaps_b,
2469 if (CF_NOT_KNOWN_P (*overlaps_a)
2470 || CF_NOT_KNOWN_P (*overlaps_b))
2471 dependence_stats.num_siv_unimplemented++;
2472 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2473 || CF_NO_DEPENDENCE_P (*overlaps_b))
2474 dependence_stats.num_siv_independent++;
2476 dependence_stats.num_siv_dependent++;
2479 goto siv_subscript_dontknow;
2484 siv_subscript_dontknow:;
2485 if (dump_file && (dump_flags & TDF_DETAILS))
2486 fprintf (dump_file, "siv test failed: unimplemented.\n");
2487 *overlaps_a = conflict_fn_not_known ();
2488 *overlaps_b = conflict_fn_not_known ();
2489 *last_conflicts = chrec_dont_know;
2490 dependence_stats.num_siv_unimplemented++;
2493 if (dump_file && (dump_flags & TDF_DETAILS))
2494 fprintf (dump_file, ")\n");
2497 /* Returns false if we can prove that the greatest common divisor of the steps
2498 of CHREC does not divide CST, false otherwise. */
2501 gcd_of_steps_may_divide_p (const_tree chrec, const_tree cst)
2503 HOST_WIDE_INT cd = 0, val;
2506 if (!host_integerp (cst, 0))
2508 val = tree_low_cst (cst, 0);
2510 while (TREE_CODE (chrec) == POLYNOMIAL_CHREC)
2512 step = CHREC_RIGHT (chrec);
2513 if (!host_integerp (step, 0))
2515 cd = gcd (cd, tree_low_cst (step, 0));
2516 chrec = CHREC_LEFT (chrec);
2519 return val % cd == 0;
2522 /* Analyze a MIV (Multiple Index Variable) subscript with respect to
2523 LOOP_NEST. *OVERLAPS_A and *OVERLAPS_B are initialized to the
2524 functions that describe the relation between the elements accessed
2525 twice by CHREC_A and CHREC_B. For k >= 0, the following property
2528 CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */
2531 analyze_miv_subscript (tree chrec_a,
2533 conflict_function **overlaps_a,
2534 conflict_function **overlaps_b,
2535 tree *last_conflicts,
2536 struct loop *loop_nest)
2538 /* FIXME: This is a MIV subscript, not yet handled.
2539 Example: (A[{1, +, 1}_1] vs. A[{1, +, 1}_2]) that comes from
2542 In the SIV test we had to solve a Diophantine equation with two
2543 variables. In the MIV case we have to solve a Diophantine
2544 equation with 2*n variables (if the subscript uses n IVs).
2546 tree type, difference;
2548 dependence_stats.num_miv++;
2549 if (dump_file && (dump_flags & TDF_DETAILS))
2550 fprintf (dump_file, "(analyze_miv_subscript \n");
2552 type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b));
2553 chrec_a = chrec_convert (type, chrec_a, NULL);
2554 chrec_b = chrec_convert (type, chrec_b, NULL);
2555 difference = chrec_fold_minus (type, chrec_a, chrec_b);
2557 if (eq_evolutions_p (chrec_a, chrec_b))
2559 /* Access functions are the same: all the elements are accessed
2560 in the same order. */
2561 *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2562 *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2563 *last_conflicts = estimated_loop_iterations_tree
2564 (get_chrec_loop (chrec_a), true);
2565 dependence_stats.num_miv_dependent++;
2568 else if (evolution_function_is_constant_p (difference)
2569 /* For the moment, the following is verified:
2570 evolution_function_is_affine_multivariate_p (chrec_a,
2572 && !gcd_of_steps_may_divide_p (chrec_a, difference))
2574 /* testsuite/.../ssa-chrec-33.c
2575 {{21, +, 2}_1, +, -2}_2 vs. {{20, +, 2}_1, +, -2}_2
2577 The difference is 1, and all the evolution steps are multiples
2578 of 2, consequently there are no overlapping elements. */
2579 *overlaps_a = conflict_fn_no_dependence ();
2580 *overlaps_b = conflict_fn_no_dependence ();
2581 *last_conflicts = integer_zero_node;
2582 dependence_stats.num_miv_independent++;
2585 else if (evolution_function_is_affine_multivariate_p (chrec_a, loop_nest->num)
2586 && !chrec_contains_symbols (chrec_a)
2587 && evolution_function_is_affine_multivariate_p (chrec_b, loop_nest->num)
2588 && !chrec_contains_symbols (chrec_b))
2590 /* testsuite/.../ssa-chrec-35.c
2591 {0, +, 1}_2 vs. {0, +, 1}_3
2592 the overlapping elements are respectively located at iterations:
2593 {0, +, 1}_x and {0, +, 1}_x,
2594 in other words, we have the equality:
2595 {0, +, 1}_2 ({0, +, 1}_x) = {0, +, 1}_3 ({0, +, 1}_x)
2598 {{0, +, 1}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y) =
2599 {0, +, 1}_1 ({{0, +, 1}_x, +, 2}_y)
2601 {{0, +, 2}_1, +, 3}_2 ({0, +, 1}_y, {0, +, 1}_x) =
2602 {{0, +, 3}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y)
2604 analyze_subscript_affine_affine (chrec_a, chrec_b,
2605 overlaps_a, overlaps_b, last_conflicts);
2607 if (CF_NOT_KNOWN_P (*overlaps_a)
2608 || CF_NOT_KNOWN_P (*overlaps_b))
2609 dependence_stats.num_miv_unimplemented++;
2610 else if (CF_NO_DEPENDENCE_P (*overlaps_a)
2611 || CF_NO_DEPENDENCE_P (*overlaps_b))
2612 dependence_stats.num_miv_independent++;
2614 dependence_stats.num_miv_dependent++;
2619 /* When the analysis is too difficult, answer "don't know". */
2620 if (dump_file && (dump_flags & TDF_DETAILS))
2621 fprintf (dump_file, "analyze_miv_subscript test failed: unimplemented.\n");
2623 *overlaps_a = conflict_fn_not_known ();
2624 *overlaps_b = conflict_fn_not_known ();
2625 *last_conflicts = chrec_dont_know;
2626 dependence_stats.num_miv_unimplemented++;
2629 if (dump_file && (dump_flags & TDF_DETAILS))
2630 fprintf (dump_file, ")\n");
2633 /* Determines the iterations for which CHREC_A is equal to CHREC_B in
2634 with respect to LOOP_NEST. OVERLAP_ITERATIONS_A and
2635 OVERLAP_ITERATIONS_B are initialized with two functions that
2636 describe the iterations that contain conflicting elements.
2638 Remark: For an integer k >= 0, the following equality is true:
2640 CHREC_A (OVERLAP_ITERATIONS_A (k)) == CHREC_B (OVERLAP_ITERATIONS_B (k)).
2644 analyze_overlapping_iterations (tree chrec_a,
2646 conflict_function **overlap_iterations_a,
2647 conflict_function **overlap_iterations_b,
2648 tree *last_conflicts, struct loop *loop_nest)
2650 unsigned int lnn = loop_nest->num;
2652 dependence_stats.num_subscript_tests++;
2654 if (dump_file && (dump_flags & TDF_DETAILS))
2656 fprintf (dump_file, "(analyze_overlapping_iterations \n");
2657 fprintf (dump_file, " (chrec_a = ");
2658 print_generic_expr (dump_file, chrec_a, 0);
2659 fprintf (dump_file, ")\n (chrec_b = ");
2660 print_generic_expr (dump_file, chrec_b, 0);
2661 fprintf (dump_file, ")\n");
2664 if (chrec_a == NULL_TREE
2665 || chrec_b == NULL_TREE
2666 || chrec_contains_undetermined (chrec_a)
2667 || chrec_contains_undetermined (chrec_b))
2669 dependence_stats.num_subscript_undetermined++;
2671 *overlap_iterations_a = conflict_fn_not_known ();
2672 *overlap_iterations_b = conflict_fn_not_known ();
2675 /* If they are the same chrec, and are affine, they overlap
2676 on every iteration. */
2677 else if (eq_evolutions_p (chrec_a, chrec_b)
2678 && evolution_function_is_affine_multivariate_p (chrec_a, lnn))
2680 dependence_stats.num_same_subscript_function++;
2681 *overlap_iterations_a = conflict_fn (1, affine_fn_cst (integer_zero_node));
2682 *overlap_iterations_b = conflict_fn (1, affine_fn_cst (integer_zero_node));
2683 *last_conflicts = chrec_dont_know;
2686 /* If they aren't the same, and aren't affine, we can't do anything
2688 else if ((chrec_contains_symbols (chrec_a)
2689 || chrec_contains_symbols (chrec_b))
2690 && (!evolution_function_is_affine_multivariate_p (chrec_a, lnn)
2691 || !evolution_function_is_affine_multivariate_p (chrec_b, lnn)))
2693 dependence_stats.num_subscript_undetermined++;
2694 *overlap_iterations_a = conflict_fn_not_known ();
2695 *overlap_iterations_b = conflict_fn_not_known ();
2698 else if (ziv_subscript_p (chrec_a, chrec_b))
2699 analyze_ziv_subscript (chrec_a, chrec_b,
2700 overlap_iterations_a, overlap_iterations_b,
2703 else if (siv_subscript_p (chrec_a, chrec_b))
2704 analyze_siv_subscript (chrec_a, chrec_b,
2705 overlap_iterations_a, overlap_iterations_b,
2706 last_conflicts, lnn);
2709 analyze_miv_subscript (chrec_a, chrec_b,
2710 overlap_iterations_a, overlap_iterations_b,
2711 last_conflicts, loop_nest);
2713 if (dump_file && (dump_flags & TDF_DETAILS))
2715 fprintf (dump_file, " (overlap_iterations_a = ");
2716 dump_conflict_function (dump_file, *overlap_iterations_a);
2717 fprintf (dump_file, ")\n (overlap_iterations_b = ");
2718 dump_conflict_function (dump_file, *overlap_iterations_b);
2719 fprintf (dump_file, ")\n");
2720 fprintf (dump_file, ")\n");
2724 /* Helper function for uniquely inserting distance vectors. */
2727 save_dist_v (struct data_dependence_relation *ddr, lambda_vector dist_v)
2732 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, v); i++)
2733 if (lambda_vector_equal (v, dist_v, DDR_NB_LOOPS (ddr)))
2736 VEC_safe_push (lambda_vector, heap, DDR_DIST_VECTS (ddr), dist_v);
2739 /* Helper function for uniquely inserting direction vectors. */
2742 save_dir_v (struct data_dependence_relation *ddr, lambda_vector dir_v)
2747 for (i = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), i, v); i++)
2748 if (lambda_vector_equal (v, dir_v, DDR_NB_LOOPS (ddr)))
2751 VEC_safe_push (lambda_vector, heap, DDR_DIR_VECTS (ddr), dir_v);
2754 /* Add a distance of 1 on all the loops outer than INDEX. If we
2755 haven't yet determined a distance for this outer loop, push a new
2756 distance vector composed of the previous distance, and a distance
2757 of 1 for this outer loop. Example:
2765 Saved vectors are of the form (dist_in_1, dist_in_2). First, we
2766 save (0, 1), then we have to save (1, 0). */
2769 add_outer_distances (struct data_dependence_relation *ddr,
2770 lambda_vector dist_v, int index)
2772 /* For each outer loop where init_v is not set, the accesses are
2773 in dependence of distance 1 in the loop. */
2774 while (--index >= 0)
2776 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2777 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
2779 save_dist_v (ddr, save_v);
2783 /* Return false when fail to represent the data dependence as a
2784 distance vector. INIT_B is set to true when a component has been
2785 added to the distance vector DIST_V. INDEX_CARRY is then set to
2786 the index in DIST_V that carries the dependence. */
2789 build_classic_dist_vector_1 (struct data_dependence_relation *ddr,
2790 struct data_reference *ddr_a,
2791 struct data_reference *ddr_b,
2792 lambda_vector dist_v, bool *init_b,
2796 lambda_vector init_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2798 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2800 tree access_fn_a, access_fn_b;
2801 struct subscript *subscript = DDR_SUBSCRIPT (ddr, i);
2803 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2805 non_affine_dependence_relation (ddr);
2809 access_fn_a = DR_ACCESS_FN (ddr_a, i);
2810 access_fn_b = DR_ACCESS_FN (ddr_b, i);
2812 if (TREE_CODE (access_fn_a) == POLYNOMIAL_CHREC
2813 && TREE_CODE (access_fn_b) == POLYNOMIAL_CHREC)
2816 int index_a = index_in_loop_nest (CHREC_VARIABLE (access_fn_a),
2817 DDR_LOOP_NEST (ddr));
2818 int index_b = index_in_loop_nest (CHREC_VARIABLE (access_fn_b),
2819 DDR_LOOP_NEST (ddr));
2821 /* The dependence is carried by the outermost loop. Example:
2828 In this case, the dependence is carried by loop_1. */
2829 index = index_a < index_b ? index_a : index_b;
2830 *index_carry = MIN (index, *index_carry);
2832 if (chrec_contains_undetermined (SUB_DISTANCE (subscript)))
2834 non_affine_dependence_relation (ddr);
2838 dist = int_cst_value (SUB_DISTANCE (subscript));
2840 /* This is the subscript coupling test. If we have already
2841 recorded a distance for this loop (a distance coming from
2842 another subscript), it should be the same. For example,
2843 in the following code, there is no dependence:
2850 if (init_v[index] != 0 && dist_v[index] != dist)
2852 finalize_ddr_dependent (ddr, chrec_known);
2856 dist_v[index] = dist;
2860 else if (!operand_equal_p (access_fn_a, access_fn_b, 0))
2862 /* This can be for example an affine vs. constant dependence
2863 (T[i] vs. T[3]) that is not an affine dependence and is
2864 not representable as a distance vector. */
2865 non_affine_dependence_relation (ddr);
2873 /* Return true when the DDR contains only constant access functions. */
2876 constant_access_functions (const struct data_dependence_relation *ddr)
2880 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2881 if (!evolution_function_is_constant_p (DR_ACCESS_FN (DDR_A (ddr), i))
2882 || !evolution_function_is_constant_p (DR_ACCESS_FN (DDR_B (ddr), i)))
2888 /* Helper function for the case where DDR_A and DDR_B are the same
2889 multivariate access function with a constant step. For an example
2893 add_multivariate_self_dist (struct data_dependence_relation *ddr, tree c_2)
2896 tree c_1 = CHREC_LEFT (c_2);
2897 tree c_0 = CHREC_LEFT (c_1);
2898 lambda_vector dist_v;
2901 /* Polynomials with more than 2 variables are not handled yet. When
2902 the evolution steps are parameters, it is not possible to
2903 represent the dependence using classical distance vectors. */
2904 if (TREE_CODE (c_0) != INTEGER_CST
2905 || TREE_CODE (CHREC_RIGHT (c_1)) != INTEGER_CST
2906 || TREE_CODE (CHREC_RIGHT (c_2)) != INTEGER_CST)
2908 DDR_AFFINE_P (ddr) = false;
2912 x_2 = index_in_loop_nest (CHREC_VARIABLE (c_2), DDR_LOOP_NEST (ddr));
2913 x_1 = index_in_loop_nest (CHREC_VARIABLE (c_1), DDR_LOOP_NEST (ddr));
2915 /* For "{{0, +, 2}_1, +, 3}_2" the distance vector is (3, -2). */
2916 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2917 v1 = int_cst_value (CHREC_RIGHT (c_1));
2918 v2 = int_cst_value (CHREC_RIGHT (c_2));
2931 save_dist_v (ddr, dist_v);
2933 add_outer_distances (ddr, dist_v, x_1);
2936 /* Helper function for the case where DDR_A and DDR_B are the same
2937 access functions. */
2940 add_other_self_distances (struct data_dependence_relation *ddr)
2942 lambda_vector dist_v;
2944 int index_carry = DDR_NB_LOOPS (ddr);
2946 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
2948 tree access_fun = DR_ACCESS_FN (DDR_A (ddr), i);
2950 if (TREE_CODE (access_fun) == POLYNOMIAL_CHREC)
2952 if (!evolution_function_is_univariate_p (access_fun))
2954 if (DDR_NUM_SUBSCRIPTS (ddr) != 1)
2956 DDR_ARE_DEPENDENT (ddr) = chrec_dont_know;
2960 access_fun = DR_ACCESS_FN (DDR_A (ddr), 0);
2962 if (TREE_CODE (CHREC_LEFT (access_fun)) == POLYNOMIAL_CHREC)
2963 add_multivariate_self_dist (ddr, access_fun);
2965 /* The evolution step is not constant: it varies in
2966 the outer loop, so this cannot be represented by a
2967 distance vector. For example in pr34635.c the
2968 evolution is {0, +, {0, +, 4}_1}_2. */
2969 DDR_AFFINE_P (ddr) = false;
2974 index_carry = MIN (index_carry,
2975 index_in_loop_nest (CHREC_VARIABLE (access_fun),
2976 DDR_LOOP_NEST (ddr)));
2980 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2981 add_outer_distances (ddr, dist_v, index_carry);
2985 insert_innermost_unit_dist_vector (struct data_dependence_relation *ddr)
2987 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
2989 dist_v[DDR_INNER_LOOP (ddr)] = 1;
2990 save_dist_v (ddr, dist_v);
2993 /* Adds a unit distance vector to DDR when there is a 0 overlap. This
2994 is the case for example when access functions are the same and
2995 equal to a constant, as in:
3002 in which case the distance vectors are (0) and (1). */
3005 add_distance_for_zero_overlaps (struct data_dependence_relation *ddr)
3009 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
3011 subscript_p sub = DDR_SUBSCRIPT (ddr, i);
3012 conflict_function *ca = SUB_CONFLICTS_IN_A (sub);
3013 conflict_function *cb = SUB_CONFLICTS_IN_B (sub);
3015 for (j = 0; j < ca->n; j++)
3016 if (affine_function_zero_p (ca->fns[j]))
3018 insert_innermost_unit_dist_vector (ddr);
3022 for (j = 0; j < cb->n; j++)
3023 if (affine_function_zero_p (cb->fns[j]))
3025 insert_innermost_unit_dist_vector (ddr);
3031 /* Compute the classic per loop distance vector. DDR is the data
3032 dependence relation to build a vector from. Return false when fail
3033 to represent the data dependence as a distance vector. */
3036 build_classic_dist_vector (struct data_dependence_relation *ddr,
3037 struct loop *loop_nest)
3039 bool init_b = false;
3040 int index_carry = DDR_NB_LOOPS (ddr);
3041 lambda_vector dist_v;
3043 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3046 if (same_access_functions (ddr))
3048 /* Save the 0 vector. */
3049 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3050 save_dist_v (ddr, dist_v);
3052 if (constant_access_functions (ddr))
3053 add_distance_for_zero_overlaps (ddr);
3055 if (DDR_NB_LOOPS (ddr) > 1)
3056 add_other_self_distances (ddr);
3061 dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3062 if (!build_classic_dist_vector_1 (ddr, DDR_A (ddr), DDR_B (ddr),
3063 dist_v, &init_b, &index_carry))
3066 /* Save the distance vector if we initialized one. */
3069 /* Verify a basic constraint: classic distance vectors should
3070 always be lexicographically positive.
3072 Data references are collected in the order of execution of
3073 the program, thus for the following loop
3075 | for (i = 1; i < 100; i++)
3076 | for (j = 1; j < 100; j++)
3078 | t = T[j+1][i-1]; // A
3079 | T[j][i] = t + 2; // B
3082 references are collected following the direction of the wind:
3083 A then B. The data dependence tests are performed also
3084 following this order, such that we're looking at the distance
3085 separating the elements accessed by A from the elements later
3086 accessed by B. But in this example, the distance returned by
3087 test_dep (A, B) is lexicographically negative (-1, 1), that
3088 means that the access A occurs later than B with respect to
3089 the outer loop, ie. we're actually looking upwind. In this
3090 case we solve test_dep (B, A) looking downwind to the
3091 lexicographically positive solution, that returns the
3092 distance vector (1, -1). */
3093 if (!lambda_vector_lexico_pos (dist_v, DDR_NB_LOOPS (ddr)))
3095 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3096 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3099 compute_subscript_distance (ddr);
3100 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3101 save_v, &init_b, &index_carry))
3103 save_dist_v (ddr, save_v);
3104 DDR_REVERSED_P (ddr) = true;
3106 /* In this case there is a dependence forward for all the
3109 | for (k = 1; k < 100; k++)
3110 | for (i = 1; i < 100; i++)
3111 | for (j = 1; j < 100; j++)
3113 | t = T[j+1][i-1]; // A
3114 | T[j][i] = t + 2; // B
3122 if (DDR_NB_LOOPS (ddr) > 1)
3124 add_outer_distances (ddr, save_v, index_carry);
3125 add_outer_distances (ddr, dist_v, index_carry);
3130 lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3131 lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr));
3133 if (DDR_NB_LOOPS (ddr) > 1)
3135 lambda_vector opposite_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3137 if (!subscript_dependence_tester_1 (ddr, DDR_B (ddr),
3138 DDR_A (ddr), loop_nest))
3140 compute_subscript_distance (ddr);
3141 if (!build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr),
3142 opposite_v, &init_b,
3146 save_dist_v (ddr, save_v);
3147 add_outer_distances (ddr, dist_v, index_carry);
3148 add_outer_distances (ddr, opposite_v, index_carry);
3151 save_dist_v (ddr, save_v);
3156 /* There is a distance of 1 on all the outer loops: Example:
3157 there is a dependence of distance 1 on loop_1 for the array A.
3163 add_outer_distances (ddr, dist_v,
3164 lambda_vector_first_nz (dist_v,
3165 DDR_NB_LOOPS (ddr), 0));
3168 if (dump_file && (dump_flags & TDF_DETAILS))
3172 fprintf (dump_file, "(build_classic_dist_vector\n");
3173 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3175 fprintf (dump_file, " dist_vector = (");
3176 print_lambda_vector (dump_file, DDR_DIST_VECT (ddr, i),
3177 DDR_NB_LOOPS (ddr));
3178 fprintf (dump_file, " )\n");
3180 fprintf (dump_file, ")\n");
3186 /* Return the direction for a given distance.
3187 FIXME: Computing dir this way is suboptimal, since dir can catch
3188 cases that dist is unable to represent. */
3190 static inline enum data_dependence_direction
3191 dir_from_dist (int dist)
3194 return dir_positive;
3196 return dir_negative;
3201 /* Compute the classic per loop direction vector. DDR is the data
3202 dependence relation to build a vector from. */
3205 build_classic_dir_vector (struct data_dependence_relation *ddr)
3208 lambda_vector dist_v;
3210 for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v); i++)
3212 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3214 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3215 dir_v[j] = dir_from_dist (dist_v[j]);
3217 save_dir_v (ddr, dir_v);
3221 /* Helper function. Returns true when there is a dependence between
3222 data references DRA and DRB. */
3225 subscript_dependence_tester_1 (struct data_dependence_relation *ddr,
3226 struct data_reference *dra,
3227 struct data_reference *drb,
3228 struct loop *loop_nest)
3231 tree last_conflicts;
3232 struct subscript *subscript;
3234 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3237 conflict_function *overlaps_a, *overlaps_b;
3239 analyze_overlapping_iterations (DR_ACCESS_FN (dra, i),
3240 DR_ACCESS_FN (drb, i),
3241 &overlaps_a, &overlaps_b,
3242 &last_conflicts, loop_nest);
3244 if (CF_NOT_KNOWN_P (overlaps_a)
3245 || CF_NOT_KNOWN_P (overlaps_b))
3247 finalize_ddr_dependent (ddr, chrec_dont_know);
3248 dependence_stats.num_dependence_undetermined++;
3249 free_conflict_function (overlaps_a);
3250 free_conflict_function (overlaps_b);
3254 else if (CF_NO_DEPENDENCE_P (overlaps_a)
3255 || CF_NO_DEPENDENCE_P (overlaps_b))
3257 finalize_ddr_dependent (ddr, chrec_known);
3258 dependence_stats.num_dependence_independent++;
3259 free_conflict_function (overlaps_a);
3260 free_conflict_function (overlaps_b);
3266 if (SUB_CONFLICTS_IN_A (subscript))
3267 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3268 if (SUB_CONFLICTS_IN_B (subscript))
3269 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3271 SUB_CONFLICTS_IN_A (subscript) = overlaps_a;
3272 SUB_CONFLICTS_IN_B (subscript) = overlaps_b;
3273 SUB_LAST_CONFLICT (subscript) = last_conflicts;
3280 /* Computes the conflicting iterations in LOOP_NEST, and initialize DDR. */
3283 subscript_dependence_tester (struct data_dependence_relation *ddr,
3284 struct loop *loop_nest)
3287 if (dump_file && (dump_flags & TDF_DETAILS))
3288 fprintf (dump_file, "(subscript_dependence_tester \n");
3290 if (subscript_dependence_tester_1 (ddr, DDR_A (ddr), DDR_B (ddr), loop_nest))
3291 dependence_stats.num_dependence_dependent++;
3293 compute_subscript_distance (ddr);
3294 if (build_classic_dist_vector (ddr, loop_nest))
3295 build_classic_dir_vector (ddr);
3297 if (dump_file && (dump_flags & TDF_DETAILS))
3298 fprintf (dump_file, ")\n");
3301 /* Returns true when all the access functions of A are affine or
3302 constant with respect to LOOP_NEST. */
3305 access_functions_are_affine_or_constant_p (const struct data_reference *a,
3306 const struct loop *loop_nest)
3309 VEC(tree,heap) *fns = DR_ACCESS_FNS (a);
3312 for (i = 0; VEC_iterate (tree, fns, i, t); i++)
3313 if (!evolution_function_is_invariant_p (t, loop_nest->num)
3314 && !evolution_function_is_affine_multivariate_p (t, loop_nest->num))
3320 /* Return true if we can create an affine data-ref for OP in STMT. */
3323 stmt_simple_memref_p (struct loop *loop, gimple stmt, tree op)
3325 data_reference_p dr;
3328 dr = create_data_ref (loop, op, stmt, true);
3329 if (!access_functions_are_affine_or_constant_p (dr, loop))
3336 /* Initializes an equation for an OMEGA problem using the information
3337 contained in the ACCESS_FUN. Returns true when the operation
3340 PB is the omega constraint system.
3341 EQ is the number of the equation to be initialized.
3342 OFFSET is used for shifting the variables names in the constraints:
3343 a constrain is composed of 2 * the number of variables surrounding
3344 dependence accesses. OFFSET is set either to 0 for the first n variables,
3345 then it is set to n.
3346 ACCESS_FUN is expected to be an affine chrec. */
3349 init_omega_eq_with_af (omega_pb pb, unsigned eq,
3350 unsigned int offset, tree access_fun,
3351 struct data_dependence_relation *ddr)
3353 switch (TREE_CODE (access_fun))
3355 case POLYNOMIAL_CHREC:
3357 tree left = CHREC_LEFT (access_fun);
3358 tree right = CHREC_RIGHT (access_fun);
3359 int var = CHREC_VARIABLE (access_fun);
3362 if (TREE_CODE (right) != INTEGER_CST)
3365 var_idx = index_in_loop_nest (var, DDR_LOOP_NEST (ddr));
3366 pb->eqs[eq].coef[offset + var_idx + 1] = int_cst_value (right);
3368 /* Compute the innermost loop index. */
3369 DDR_INNER_LOOP (ddr) = MAX (DDR_INNER_LOOP (ddr), var_idx);
3372 pb->eqs[eq].coef[var_idx + DDR_NB_LOOPS (ddr) + 1]
3373 += int_cst_value (right);
3375 switch (TREE_CODE (left))
3377 case POLYNOMIAL_CHREC:
3378 return init_omega_eq_with_af (pb, eq, offset, left, ddr);
3381 pb->eqs[eq].coef[0] += int_cst_value (left);
3390 pb->eqs[eq].coef[0] += int_cst_value (access_fun);
3398 /* As explained in the comments preceding init_omega_for_ddr, we have
3399 to set up a system for each loop level, setting outer loops
3400 variation to zero, and current loop variation to positive or zero.
3401 Save each lexico positive distance vector. */
3404 omega_extract_distance_vectors (omega_pb pb,
3405 struct data_dependence_relation *ddr)
3409 struct loop *loopi, *loopj;
3410 enum omega_result res;
3412 /* Set a new problem for each loop in the nest. The basis is the
3413 problem that we have initialized until now. On top of this we
3414 add new constraints. */
3415 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3416 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3419 omega_pb copy = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr),
3420 DDR_NB_LOOPS (ddr));
3422 omega_copy_problem (copy, pb);
3424 /* For all the outer loops "loop_j", add "dj = 0". */
3426 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3428 eq = omega_add_zero_eq (copy, omega_black);
3429 copy->eqs[eq].coef[j + 1] = 1;
3432 /* For "loop_i", add "0 <= di". */
3433 geq = omega_add_zero_geq (copy, omega_black);
3434 copy->geqs[geq].coef[i + 1] = 1;
3436 /* Reduce the constraint system, and test that the current
3437 problem is feasible. */
3438 res = omega_simplify_problem (copy);
3439 if (res == omega_false
3440 || res == omega_unknown
3441 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3444 for (eq = 0; eq < copy->num_subs; eq++)
3445 if (copy->subs[eq].key == (int) i + 1)
3447 dist = copy->subs[eq].coef[0];
3453 /* Reinitialize problem... */
3454 omega_copy_problem (copy, pb);
3456 j < i && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), j, loopj); j++)
3458 eq = omega_add_zero_eq (copy, omega_black);
3459 copy->eqs[eq].coef[j + 1] = 1;
3462 /* ..., but this time "di = 1". */
3463 eq = omega_add_zero_eq (copy, omega_black);
3464 copy->eqs[eq].coef[i + 1] = 1;
3465 copy->eqs[eq].coef[0] = -1;
3467 res = omega_simplify_problem (copy);
3468 if (res == omega_false
3469 || res == omega_unknown
3470 || copy->num_geqs > (int) DDR_NB_LOOPS (ddr))
3473 for (eq = 0; eq < copy->num_subs; eq++)
3474 if (copy->subs[eq].key == (int) i + 1)
3476 dist = copy->subs[eq].coef[0];
3482 /* Save the lexicographically positive distance vector. */
3485 lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3486 lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3490 for (eq = 0; eq < copy->num_subs; eq++)
3491 if (copy->subs[eq].key > 0)
3493 dist = copy->subs[eq].coef[0];
3494 dist_v[copy->subs[eq].key - 1] = dist;
3497 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3498 dir_v[j] = dir_from_dist (dist_v[j]);
3500 save_dist_v (ddr, dist_v);
3501 save_dir_v (ddr, dir_v);
3505 omega_free_problem (copy);
3509 /* This is called for each subscript of a tuple of data references:
3510 insert an equality for representing the conflicts. */
3513 omega_setup_subscript (tree access_fun_a, tree access_fun_b,
3514 struct data_dependence_relation *ddr,
3515 omega_pb pb, bool *maybe_dependent)
3518 tree type = signed_type_for_types (TREE_TYPE (access_fun_a),
3519 TREE_TYPE (access_fun_b));
3520 tree fun_a = chrec_convert (type, access_fun_a, NULL);
3521 tree fun_b = chrec_convert (type, access_fun_b, NULL);
3522 tree difference = chrec_fold_minus (type, fun_a, fun_b);
3524 /* When the fun_a - fun_b is not constant, the dependence is not
3525 captured by the classic distance vector representation. */
3526 if (TREE_CODE (difference) != INTEGER_CST)
3530 if (ziv_subscript_p (fun_a, fun_b) && !integer_zerop (difference))
3532 /* There is no dependence. */
3533 *maybe_dependent = false;
3537 fun_b = chrec_fold_multiply (type, fun_b, integer_minus_one_node);
3539 eq = omega_add_zero_eq (pb, omega_black);
3540 if (!init_omega_eq_with_af (pb, eq, DDR_NB_LOOPS (ddr), fun_a, ddr)
3541 || !init_omega_eq_with_af (pb, eq, 0, fun_b, ddr))
3542 /* There is probably a dependence, but the system of
3543 constraints cannot be built: answer "don't know". */
3547 if (DDR_NB_LOOPS (ddr) != 0 && pb->eqs[eq].coef[0]
3548 && !int_divides_p (lambda_vector_gcd
3549 ((lambda_vector) &(pb->eqs[eq].coef[1]),
3550 2 * DDR_NB_LOOPS (ddr)),
3551 pb->eqs[eq].coef[0]))
3553 /* There is no dependence. */
3554 *maybe_dependent = false;
3561 /* Helper function, same as init_omega_for_ddr but specialized for
3562 data references A and B. */
3565 init_omega_for_ddr_1 (struct data_reference *dra, struct data_reference *drb,
3566 struct data_dependence_relation *ddr,
3567 omega_pb pb, bool *maybe_dependent)
3572 unsigned nb_loops = DDR_NB_LOOPS (ddr);
3574 /* Insert an equality per subscript. */
3575 for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++)
3577 if (!omega_setup_subscript (DR_ACCESS_FN (dra, i), DR_ACCESS_FN (drb, i),
3578 ddr, pb, maybe_dependent))
3580 else if (*maybe_dependent == false)
3582 /* There is no dependence. */
3583 DDR_ARE_DEPENDENT (ddr) = chrec_known;
3588 /* Insert inequalities: constraints corresponding to the iteration
3589 domain, i.e. the loops surrounding the references "loop_x" and
3590 the distance variables "dx". The layout of the OMEGA
3591 representation is as follows:
3592 - coef[0] is the constant
3593 - coef[1..nb_loops] are the protected variables that will not be
3594 removed by the solver: the "dx"
3595 - coef[nb_loops + 1, 2*nb_loops] are the loop variables: "loop_x".
3597 for (i = 0; i <= DDR_INNER_LOOP (ddr)
3598 && VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++)
3600 HOST_WIDE_INT nbi = estimated_loop_iterations_int (loopi, false);
3603 ineq = omega_add_zero_geq (pb, omega_black);
3604 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3606 /* 0 <= loop_x + dx */
3607 ineq = omega_add_zero_geq (pb, omega_black);
3608 pb->geqs[ineq].coef[i + nb_loops + 1] = 1;
3609 pb->geqs[ineq].coef[i + 1] = 1;
3613 /* loop_x <= nb_iters */
3614 ineq = omega_add_zero_geq (pb, omega_black);
3615 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3616 pb->geqs[ineq].coef[0] = nbi;
3618 /* loop_x + dx <= nb_iters */
3619 ineq = omega_add_zero_geq (pb, omega_black);
3620 pb->geqs[ineq].coef[i + nb_loops + 1] = -1;
3621 pb->geqs[ineq].coef[i + 1] = -1;
3622 pb->geqs[ineq].coef[0] = nbi;
3624 /* A step "dx" bigger than nb_iters is not feasible, so
3625 add "0 <= nb_iters + dx", */
3626 ineq = omega_add_zero_geq (pb, omega_black);
3627 pb->geqs[ineq].coef[i + 1] = 1;
3628 pb->geqs[ineq].coef[0] = nbi;
3629 /* and "dx <= nb_iters". */
3630 ineq = omega_add_zero_geq (pb, omega_black);
3631 pb->geqs[ineq].coef[i + 1] = -1;
3632 pb->geqs[ineq].coef[0] = nbi;
3636 omega_extract_distance_vectors (pb, ddr);
3641 /* Sets up the Omega dependence problem for the data dependence
3642 relation DDR. Returns false when the constraint system cannot be
3643 built, ie. when the test answers "don't know". Returns true
3644 otherwise, and when independence has been proved (using one of the
3645 trivial dependence test), set MAYBE_DEPENDENT to false, otherwise
3646 set MAYBE_DEPENDENT to true.
3648 Example: for setting up the dependence system corresponding to the
3649 conflicting accesses
3654 | ... A[2*j, 2*(i + j)]
3658 the following constraints come from the iteration domain:
3665 where di, dj are the distance variables. The constraints
3666 representing the conflicting elements are:
3669 i + 1 = 2 * (i + di + j + dj)
3671 For asking that the resulting distance vector (di, dj) be
3672 lexicographically positive, we insert the constraint "di >= 0". If
3673 "di = 0" in the solution, we fix that component to zero, and we
3674 look at the inner loops: we set a new problem where all the outer
3675 loop distances are zero, and fix this inner component to be
3676 positive. When one of the components is positive, we save that
3677 distance, and set a new problem where the distance on this loop is
3678 zero, searching for other distances in the inner loops. Here is
3679 the classic example that illustrates that we have to set for each
3680 inner loop a new problem:
3688 we have to save two distances (1, 0) and (0, 1).
3690 Given two array references, refA and refB, we have to set the
3691 dependence problem twice, refA vs. refB and refB vs. refA, and we
3692 cannot do a single test, as refB might occur before refA in the
3693 inner loops, and the contrary when considering outer loops: ex.
3698 | T[{1,+,1}_2][{1,+,1}_1] // refA
3699 | T[{2,+,1}_2][{0,+,1}_1] // refB
3704 refB touches the elements in T before refA, and thus for the same
3705 loop_0 refB precedes refA: ie. the distance vector (0, 1, -1)
3706 but for successive loop_0 iterations, we have (1, -1, 1)
3708 The Omega solver expects the distance variables ("di" in the
3709 previous example) to come first in the constraint system (as
3710 variables to be protected, or "safe" variables), the constraint
3711 system is built using the following layout:
3713 "cst | distance vars | index vars".
3717 init_omega_for_ddr (struct data_dependence_relation *ddr,
3718 bool *maybe_dependent)
3723 *maybe_dependent = true;
3725 if (same_access_functions (ddr))
3728 lambda_vector dir_v;
3730 /* Save the 0 vector. */
3731 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3732 dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
3733 for (j = 0; j < DDR_NB_LOOPS (ddr); j++)
3734 dir_v[j] = dir_equal;
3735 save_dir_v (ddr, dir_v);
3737 /* Save the dependences carried by outer loops. */
3738 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3739 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3741 omega_free_problem (pb);
3745 /* Omega expects the protected variables (those that have to be kept
3746 after elimination) to appear first in the constraint system.
3747 These variables are the distance variables. In the following
3748 initialization we declare NB_LOOPS safe variables, and the total
3749 number of variables for the constraint system is 2*NB_LOOPS. */
3750 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3751 res = init_omega_for_ddr_1 (DDR_A (ddr), DDR_B (ddr), ddr, pb,
3753 omega_free_problem (pb);
3755 /* Stop computation if not decidable, or no dependence. */
3756 if (res == false || *maybe_dependent == false)
3759 pb = omega_alloc_problem (2 * DDR_NB_LOOPS (ddr), DDR_NB_LOOPS (ddr));
3760 res = init_omega_for_ddr_1 (DDR_B (ddr), DDR_A (ddr), ddr, pb,
3762 omega_free_problem (pb);
3767 /* Return true when DDR contains the same information as that stored
3768 in DIR_VECTS and in DIST_VECTS, return false otherwise. */
3771 ddr_consistent_p (FILE *file,
3772 struct data_dependence_relation *ddr,
3773 VEC (lambda_vector, heap) *dist_vects,
3774 VEC (lambda_vector, heap) *dir_vects)
3778 /* If dump_file is set, output there. */
3779 if (dump_file && (dump_flags & TDF_DETAILS))
3782 if (VEC_length (lambda_vector, dist_vects) != DDR_NUM_DIST_VECTS (ddr))
3784 lambda_vector b_dist_v;
3785 fprintf (file, "\n(Number of distance vectors differ: Banerjee has %d, Omega has %d.\n",
3786 VEC_length (lambda_vector, dist_vects),
3787 DDR_NUM_DIST_VECTS (ddr));
3789 fprintf (file, "Banerjee dist vectors:\n");
3790 for (i = 0; VEC_iterate (lambda_vector, dist_vects, i, b_dist_v); i++)
3791 print_lambda_vector (file, b_dist_v, DDR_NB_LOOPS (ddr));
3793 fprintf (file, "Omega dist vectors:\n");
3794 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3795 print_lambda_vector (file, DDR_DIST_VECT (ddr, i), DDR_NB_LOOPS (ddr));
3797 fprintf (file, "data dependence relation:\n");
3798 dump_data_dependence_relation (file, ddr);
3800 fprintf (file, ")\n");
3804 if (VEC_length (lambda_vector, dir_vects) != DDR_NUM_DIR_VECTS (ddr))
3806 fprintf (file, "\n(Number of direction vectors differ: Banerjee has %d, Omega has %d.)\n",
3807 VEC_length (lambda_vector, dir_vects),
3808 DDR_NUM_DIR_VECTS (ddr));
3812 for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++)
3814 lambda_vector a_dist_v;
3815 lambda_vector b_dist_v = DDR_DIST_VECT (ddr, i);
3817 /* Distance vectors are not ordered in the same way in the DDR
3818 and in the DIST_VECTS: search for a matching vector. */
3819 for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, a_dist_v); j++)
3820 if (lambda_vector_equal (a_dist_v, b_dist_v, DDR_NB_LOOPS (ddr)))
3823 if (j == VEC_length (lambda_vector, dist_vects))
3825 fprintf (file, "\n(Dist vectors from the first dependence analyzer:\n");
3826 print_dist_vectors (file, dist_vects, DDR_NB_LOOPS (ddr));
3827 fprintf (file, "not found in Omega dist vectors:\n");
3828 print_dist_vectors (file, DDR_DIST_VECTS (ddr), DDR_NB_LOOPS (ddr));
3829 fprintf (file, "data dependence relation:\n");
3830 dump_data_dependence_relation (file, ddr);
3831 fprintf (file, ")\n");
3835 for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++)
3837 lambda_vector a_dir_v;
3838 lambda_vector b_dir_v = DDR_DIR_VECT (ddr, i);
3840 /* Direction vectors are not ordered in the same way in the DDR
3841 and in the DIR_VECTS: search for a matching vector. */
3842 for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, a_dir_v); j++)
3843 if (lambda_vector_equal (a_dir_v, b_dir_v, DDR_NB_LOOPS (ddr)))
3846 if (j == VEC_length (lambda_vector, dist_vects))
3848 fprintf (file, "\n(Dir vectors from the first dependence analyzer:\n");
3849 print_dir_vectors (file, dir_vects, DDR_NB_LOOPS (ddr));
3850 fprintf (file, "not found in Omega dir vectors:\n");
3851 print_dir_vectors (file, DDR_DIR_VECTS (ddr), DDR_NB_LOOPS (ddr));
3852 fprintf (file, "data dependence relation:\n");
3853 dump_data_dependence_relation (file, ddr);
3854 fprintf (file, ")\n");
3861 /* This computes the affine dependence relation between A and B with
3862 respect to LOOP_NEST. CHREC_KNOWN is used for representing the
3863 independence between two accesses, while CHREC_DONT_KNOW is used
3864 for representing the unknown relation.
3866 Note that it is possible to stop the computation of the dependence
3867 relation the first time we detect a CHREC_KNOWN element for a given
3871 compute_affine_dependence (struct data_dependence_relation *ddr,
3872 struct loop *loop_nest)
3874 struct data_reference *dra = DDR_A (ddr);
3875 struct data_reference *drb = DDR_B (ddr);
3877 if (dump_file && (dump_flags & TDF_DETAILS))
3879 fprintf (dump_file, "(compute_affine_dependence\n");
3880 fprintf (dump_file, " (stmt_a = \n");
3881 print_gimple_stmt (dump_file, DR_STMT (dra), 0, 0);
3882 fprintf (dump_file, ")\n (stmt_b = \n");
3883 print_gimple_stmt (dump_file, DR_STMT (drb), 0, 0);
3884 fprintf (dump_file, ")\n");
3887 /* Analyze only when the dependence relation is not yet known. */
3888 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE
3889 && !DDR_SELF_REFERENCE (ddr))
3891 dependence_stats.num_dependence_tests++;
3893 if (access_functions_are_affine_or_constant_p (dra, loop_nest)
3894 && access_functions_are_affine_or_constant_p (drb, loop_nest))
3896 if (flag_check_data_deps)
3898 /* Compute the dependences using the first algorithm. */
3899 subscript_dependence_tester (ddr, loop_nest);
3901 if (dump_file && (dump_flags & TDF_DETAILS))
3903 fprintf (dump_file, "\n\nBanerjee Analyzer\n");
3904 dump_data_dependence_relation (dump_file, ddr);
3907 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
3909 bool maybe_dependent;
3910 VEC (lambda_vector, heap) *dir_vects, *dist_vects;
3912 /* Save the result of the first DD analyzer. */
3913 dist_vects = DDR_DIST_VECTS (ddr);
3914 dir_vects = DDR_DIR_VECTS (ddr);
3916 /* Reset the information. */
3917 DDR_DIST_VECTS (ddr) = NULL;
3918 DDR_DIR_VECTS (ddr) = NULL;
3920 /* Compute the same information using Omega. */
3921 if (!init_omega_for_ddr (ddr, &maybe_dependent))
3922 goto csys_dont_know;
3924 if (dump_file && (dump_flags & TDF_DETAILS))
3926 fprintf (dump_file, "Omega Analyzer\n");
3927 dump_data_dependence_relation (dump_file, ddr);
3930 /* Check that we get the same information. */
3931 if (maybe_dependent)
3932 gcc_assert (ddr_consistent_p (stderr, ddr, dist_vects,
3937 subscript_dependence_tester (ddr, loop_nest);
3940 /* As a last case, if the dependence cannot be determined, or if
3941 the dependence is considered too difficult to determine, answer
3946 dependence_stats.num_dependence_undetermined++;
3948 if (dump_file && (dump_flags & TDF_DETAILS))
3950 fprintf (dump_file, "Data ref a:\n");
3951 dump_data_reference (dump_file, dra);
3952 fprintf (dump_file, "Data ref b:\n");
3953 dump_data_reference (dump_file, drb);
3954 fprintf (dump_file, "affine dependence test not usable: access function not affine or constant.\n");
3956 finalize_ddr_dependent (ddr, chrec_dont_know);
3960 if (dump_file && (dump_flags & TDF_DETAILS))
3961 fprintf (dump_file, ")\n");
3964 /* This computes the dependence relation for the same data
3965 reference into DDR. */
3968 compute_self_dependence (struct data_dependence_relation *ddr)
3971 struct subscript *subscript;
3973 if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE)
3976 for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript);
3979 if (SUB_CONFLICTS_IN_A (subscript))
3980 free_conflict_function (SUB_CONFLICTS_IN_A (subscript));
3981 if (SUB_CONFLICTS_IN_B (subscript))
3982 free_conflict_function (SUB_CONFLICTS_IN_B (subscript));
3984 /* The accessed index overlaps for each iteration. */
3985 SUB_CONFLICTS_IN_A (subscript)
3986 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3987 SUB_CONFLICTS_IN_B (subscript)
3988 = conflict_fn (1, affine_fn_cst (integer_zero_node));
3989 SUB_LAST_CONFLICT (subscript) = chrec_dont_know;
3992 /* The distance vector is the zero vector. */
3993 save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3994 save_dir_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr)));
3997 /* Compute in DEPENDENCE_RELATIONS the data dependence graph for all
3998 the data references in DATAREFS, in the LOOP_NEST. When
3999 COMPUTE_SELF_AND_RR is FALSE, don't compute read-read and self
4003 compute_all_dependences (VEC (data_reference_p, heap) *datarefs,
4004 VEC (ddr_p, heap) **dependence_relations,
4005 VEC (loop_p, heap) *loop_nest,
4006 bool compute_self_and_rr)
4008 struct data_dependence_relation *ddr;
4009 struct data_reference *a, *b;
4012 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4013 for (j = i + 1; VEC_iterate (data_reference_p, datarefs, j, b); j++)
4014 if (!DR_IS_READ (a) || !DR_IS_READ (b) || compute_self_and_rr)
4016 ddr = initialize_data_dependence_relation (a, b, loop_nest);
4017 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4018 compute_affine_dependence (ddr, VEC_index (loop_p, loop_nest, 0));
4021 if (compute_self_and_rr)
4022 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++)
4024 ddr = initialize_data_dependence_relation (a, a, loop_nest);
4025 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4026 compute_self_dependence (ddr);
4030 /* Stores the locations of memory references in STMT to REFERENCES. Returns
4031 true if STMT clobbers memory, false otherwise. */
4034 get_references_in_stmt (gimple stmt, VEC (data_ref_loc, heap) **references)
4036 bool clobbers_memory = false;
4039 enum gimple_code stmt_code = gimple_code (stmt);
4043 /* ASM_EXPR and CALL_EXPR may embed arbitrary side effects.
4044 Calls have side-effects, except those to const or pure
4046 if ((stmt_code == GIMPLE_CALL
4047 && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
4048 || (stmt_code == GIMPLE_ASM
4049 && gimple_asm_volatile_p (stmt)))
4050 clobbers_memory = true;
4052 if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
4053 return clobbers_memory;
4055 if (stmt_code == GIMPLE_ASSIGN)
4058 op0 = gimple_assign_lhs_ptr (stmt);
4059 op1 = gimple_assign_rhs1_ptr (stmt);
4062 || (REFERENCE_CLASS_P (*op1)
4063 && (base = get_base_address (*op1))
4064 && TREE_CODE (base) != SSA_NAME))
4066 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4068 ref->is_read = true;
4072 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4074 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4076 ref->is_read = false;
4079 else if (stmt_code == GIMPLE_CALL)
4081 unsigned i, n = gimple_call_num_args (stmt);
4083 for (i = 0; i < n; i++)
4085 op0 = gimple_call_arg_ptr (stmt, i);
4088 || (REFERENCE_CLASS_P (*op0) && get_base_address (*op0)))
4090 ref = VEC_safe_push (data_ref_loc, heap, *references, NULL);
4092 ref->is_read = true;
4097 return clobbers_memory;
4100 /* Stores the data references in STMT to DATAREFS. If there is an unanalyzable
4101 reference, returns false, otherwise returns true. NEST is the outermost
4102 loop of the loop nest in which the references should be analyzed. */
4105 find_data_references_in_stmt (struct loop *nest, gimple stmt,
4106 VEC (data_reference_p, heap) **datarefs)
4109 VEC (data_ref_loc, heap) *references;
4112 data_reference_p dr;
4114 if (get_references_in_stmt (stmt, &references))
4116 VEC_free (data_ref_loc, heap, references);
4120 for (i = 0; VEC_iterate (data_ref_loc, references, i, ref); i++)
4122 dr = create_data_ref (nest, *ref->pos, stmt, ref->is_read);
4123 gcc_assert (dr != NULL);
4125 /* FIXME -- data dependence analysis does not work correctly for objects with
4126 invariant addresses. Let us fail here until the problem is fixed. */
4127 if (dr_address_invariant_p (dr))
4130 if (dump_file && (dump_flags & TDF_DETAILS))
4131 fprintf (dump_file, "\tFAILED as dr address is invariant\n");
4136 VEC_safe_push (data_reference_p, heap, *datarefs, dr);
4138 VEC_free (data_ref_loc, heap, references);
4142 /* Search the data references in LOOP, and record the information into
4143 DATAREFS. Returns chrec_dont_know when failing to analyze a
4144 difficult case, returns NULL_TREE otherwise.
4146 TODO: This function should be made smarter so that it can handle address
4147 arithmetic as if they were array accesses, etc. */
4150 find_data_references_in_loop (struct loop *loop,
4151 VEC (data_reference_p, heap) **datarefs)
4153 basic_block bb, *bbs;
4155 gimple_stmt_iterator bsi;
4157 bbs = get_loop_body_in_dom_order (loop);
4159 for (i = 0; i < loop->num_nodes; i++)
4163 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4165 gimple stmt = gsi_stmt (bsi);
4167 if (!find_data_references_in_stmt (loop, stmt, datarefs))
4169 struct data_reference *res;
4170 res = XCNEW (struct data_reference);
4171 VEC_safe_push (data_reference_p, heap, *datarefs, res);
4174 return chrec_dont_know;
4183 /* Recursive helper function. */
4186 find_loop_nest_1 (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4188 /* Inner loops of the nest should not contain siblings. Example:
4189 when there are two consecutive loops,
4200 the dependence relation cannot be captured by the distance
4205 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4207 return find_loop_nest_1 (loop->inner, loop_nest);
4211 /* Return false when the LOOP is not well nested. Otherwise return
4212 true and insert in LOOP_NEST the loops of the nest. LOOP_NEST will
4213 contain the loops from the outermost to the innermost, as they will
4214 appear in the classic distance vector. */
4217 find_loop_nest (struct loop *loop, VEC (loop_p, heap) **loop_nest)
4219 VEC_safe_push (loop_p, heap, *loop_nest, loop);
4221 return find_loop_nest_1 (loop->inner, loop_nest);
4225 /* Returns true when the data dependences have been computed, false otherwise.
4226 Given a loop nest LOOP, the following vectors are returned:
4227 DATAREFS is initialized to all the array elements contained in this loop,
4228 DEPENDENCE_RELATIONS contains the relations between the data references.
4229 Compute read-read and self relations if
4230 COMPUTE_SELF_AND_READ_READ_DEPENDENCES is TRUE. */
4233 compute_data_dependences_for_loop (struct loop *loop,
4234 bool compute_self_and_read_read_dependences,
4235 VEC (data_reference_p, heap) **datarefs,
4236 VEC (ddr_p, heap) **dependence_relations)
4239 VEC (loop_p, heap) *vloops = VEC_alloc (loop_p, heap, 3);
4241 memset (&dependence_stats, 0, sizeof (dependence_stats));
4243 /* If the loop nest is not well formed, or one of the data references
4244 is not computable, give up without spending time to compute other
4247 || !find_loop_nest (loop, &vloops)
4248 || find_data_references_in_loop (loop, datarefs) == chrec_dont_know)
4250 struct data_dependence_relation *ddr;
4252 /* Insert a single relation into dependence_relations:
4254 ddr = initialize_data_dependence_relation (NULL, NULL, vloops);
4255 VEC_safe_push (ddr_p, heap, *dependence_relations, ddr);
4259 compute_all_dependences (*datarefs, dependence_relations, vloops,
4260 compute_self_and_read_read_dependences);
4262 if (dump_file && (dump_flags & TDF_STATS))
4264 fprintf (dump_file, "Dependence tester statistics:\n");
4266 fprintf (dump_file, "Number of dependence tests: %d\n",
4267 dependence_stats.num_dependence_tests);
4268 fprintf (dump_file, "Number of dependence tests classified dependent: %d\n",
4269 dependence_stats.num_dependence_dependent);
4270 fprintf (dump_file, "Number of dependence tests classified independent: %d\n",
4271 dependence_stats.num_dependence_independent);
4272 fprintf (dump_file, "Number of undetermined dependence tests: %d\n",
4273 dependence_stats.num_dependence_undetermined);
4275 fprintf (dump_file, "Number of subscript tests: %d\n",
4276 dependence_stats.num_subscript_tests);
4277 fprintf (dump_file, "Number of undetermined subscript tests: %d\n",
4278 dependence_stats.num_subscript_undetermined);
4279 fprintf (dump_file, "Number of same subscript function: %d\n",
4280 dependence_stats.num_same_subscript_function);
4282 fprintf (dump_file, "Number of ziv tests: %d\n",
4283 dependence_stats.num_ziv);
4284 fprintf (dump_file, "Number of ziv tests returning dependent: %d\n",
4285 dependence_stats.num_ziv_dependent);
4286 fprintf (dump_file, "Number of ziv tests returning independent: %d\n",
4287 dependence_stats.num_ziv_independent);
4288 fprintf (dump_file, "Number of ziv tests unimplemented: %d\n",
4289 dependence_stats.num_ziv_unimplemented);
4291 fprintf (dump_file, "Number of siv tests: %d\n",
4292 dependence_stats.num_siv);
4293 fprintf (dump_file, "Number of siv tests returning dependent: %d\n",
4294 dependence_stats.num_siv_dependent);
4295 fprintf (dump_file, "Number of siv tests returning independent: %d\n",
4296 dependence_stats.num_siv_independent);
4297 fprintf (dump_file, "Number of siv tests unimplemented: %d\n",
4298 dependence_stats.num_siv_unimplemented);
4300 fprintf (dump_file, "Number of miv tests: %d\n",
4301 dependence_stats.num_miv);
4302 fprintf (dump_file, "Number of miv tests returning dependent: %d\n",
4303 dependence_stats.num_miv_dependent);
4304 fprintf (dump_file, "Number of miv tests returning independent: %d\n",
4305 dependence_stats.num_miv_independent);
4306 fprintf (dump_file, "Number of miv tests unimplemented: %d\n",
4307 dependence_stats.num_miv_unimplemented);
4313 /* Entry point (for testing only). Analyze all the data references
4314 and the dependence relations in LOOP.
4316 The data references are computed first.
4318 A relation on these nodes is represented by a complete graph. Some
4319 of the relations could be of no interest, thus the relations can be
4322 In the following function we compute all the relations. This is
4323 just a first implementation that is here for:
4324 - for showing how to ask for the dependence relations,
4325 - for the debugging the whole dependence graph,
4326 - for the dejagnu testcases and maintenance.
4328 It is possible to ask only for a part of the graph, avoiding to
4329 compute the whole dependence graph. The computed dependences are
4330 stored in a knowledge base (KB) such that later queries don't
4331 recompute the same information. The implementation of this KB is
4332 transparent to the optimizer, and thus the KB can be changed with a
4333 more efficient implementation, or the KB could be disabled. */
4335 analyze_all_data_dependences (struct loop *loop)
4338 int nb_data_refs = 10;
4339 VEC (data_reference_p, heap) *datarefs =
4340 VEC_alloc (data_reference_p, heap, nb_data_refs);
4341 VEC (ddr_p, heap) *dependence_relations =
4342 VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs);
4344 /* Compute DDs on the whole function. */
4345 compute_data_dependences_for_loop (loop, false, &datarefs,
4346 &dependence_relations);
4350 dump_data_dependence_relations (dump_file, dependence_relations);
4351 fprintf (dump_file, "\n\n");
4353 if (dump_flags & TDF_DETAILS)
4354 dump_dist_dir_vectors (dump_file, dependence_relations);
4356 if (dump_flags & TDF_STATS)
4358 unsigned nb_top_relations = 0;
4359 unsigned nb_bot_relations = 0;
4360 unsigned nb_basename_differ = 0;
4361 unsigned nb_chrec_relations = 0;
4362 struct data_dependence_relation *ddr;
4364 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4366 if (chrec_contains_undetermined (DDR_ARE_DEPENDENT (ddr)))
4369 else if (DDR_ARE_DEPENDENT (ddr) == chrec_known)
4371 struct data_reference *a = DDR_A (ddr);
4372 struct data_reference *b = DDR_B (ddr);
4374 if (!bitmap_intersect_p (DR_VOPS (a), DR_VOPS (b)))
4375 nb_basename_differ++;
4381 nb_chrec_relations++;
4384 gather_stats_on_scev_database ();
4388 free_dependence_relations (dependence_relations);
4389 free_data_refs (datarefs);
4392 /* Computes all the data dependences and check that the results of
4393 several analyzers are the same. */
4396 tree_check_data_deps (void)
4399 struct loop *loop_nest;
4401 FOR_EACH_LOOP (li, loop_nest, 0)
4402 analyze_all_data_dependences (loop_nest);
4405 /* Free the memory used by a data dependence relation DDR. */
4408 free_dependence_relation (struct data_dependence_relation *ddr)
4413 if (DDR_SUBSCRIPTS (ddr))
4414 free_subscripts (DDR_SUBSCRIPTS (ddr));
4415 if (DDR_DIST_VECTS (ddr))
4416 VEC_free (lambda_vector, heap, DDR_DIST_VECTS (ddr));
4417 if (DDR_DIR_VECTS (ddr))
4418 VEC_free (lambda_vector, heap, DDR_DIR_VECTS (ddr));
4423 /* Free the memory used by the data dependence relations from
4424 DEPENDENCE_RELATIONS. */
4427 free_dependence_relations (VEC (ddr_p, heap) *dependence_relations)
4430 struct data_dependence_relation *ddr;
4431 VEC (loop_p, heap) *loop_nest = NULL;
4433 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4437 if (loop_nest == NULL)
4438 loop_nest = DDR_LOOP_NEST (ddr);
4440 gcc_assert (DDR_LOOP_NEST (ddr) == NULL
4441 || DDR_LOOP_NEST (ddr) == loop_nest);
4442 free_dependence_relation (ddr);
4446 VEC_free (loop_p, heap, loop_nest);
4447 VEC_free (ddr_p, heap, dependence_relations);
4450 /* Free the memory used by the data references from DATAREFS. */
4453 free_data_refs (VEC (data_reference_p, heap) *datarefs)
4456 struct data_reference *dr;
4458 for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++)
4460 VEC_free (data_reference_p, heap, datarefs);
4465 /* Dump vertex I in RDG to FILE. */
4468 dump_rdg_vertex (FILE *file, struct graph *rdg, int i)
4470 struct vertex *v = &(rdg->vertices[i]);
4471 struct graph_edge *e;
4473 fprintf (file, "(vertex %d: (%s%s) (in:", i,
4474 RDG_MEM_WRITE_STMT (rdg, i) ? "w" : "",
4475 RDG_MEM_READS_STMT (rdg, i) ? "r" : "");
4478 for (e = v->pred; e; e = e->pred_next)
4479 fprintf (file, " %d", e->src);
4481 fprintf (file, ") (out:");
4484 for (e = v->succ; e; e = e->succ_next)
4485 fprintf (file, " %d", e->dest);
4487 fprintf (file, ") \n");
4488 print_gimple_stmt (file, RDGV_STMT (v), 0, TDF_VOPS|TDF_MEMSYMS);
4489 fprintf (file, ")\n");
4492 /* Call dump_rdg_vertex on stderr. */
4495 debug_rdg_vertex (struct graph *rdg, int i)
4497 dump_rdg_vertex (stderr, rdg, i);
4500 /* Dump component C of RDG to FILE. If DUMPED is non-null, set the
4501 dumped vertices to that bitmap. */
4503 void dump_rdg_component (FILE *file, struct graph *rdg, int c, bitmap dumped)
4507 fprintf (file, "(%d\n", c);
4509 for (i = 0; i < rdg->n_vertices; i++)
4510 if (rdg->vertices[i].component == c)
4513 bitmap_set_bit (dumped, i);
4515 dump_rdg_vertex (file, rdg, i);
4518 fprintf (file, ")\n");
4521 /* Call dump_rdg_vertex on stderr. */
4524 debug_rdg_component (struct graph *rdg, int c)
4526 dump_rdg_component (stderr, rdg, c, NULL);
4529 /* Dump the reduced dependence graph RDG to FILE. */
4532 dump_rdg (FILE *file, struct graph *rdg)
4535 bitmap dumped = BITMAP_ALLOC (NULL);
4537 fprintf (file, "(rdg\n");
4539 for (i = 0; i < rdg->n_vertices; i++)
4540 if (!bitmap_bit_p (dumped, i))
4541 dump_rdg_component (file, rdg, rdg->vertices[i].component, dumped);
4543 fprintf (file, ")\n");
4544 BITMAP_FREE (dumped);
4547 /* Call dump_rdg on stderr. */
4550 debug_rdg (struct graph *rdg)
4552 dump_rdg (stderr, rdg);
4556 dot_rdg_1 (FILE *file, struct graph *rdg)
4560 fprintf (file, "digraph RDG {\n");
4562 for (i = 0; i < rdg->n_vertices; i++)
4564 struct vertex *v = &(rdg->vertices[i]);
4565 struct graph_edge *e;
4567 /* Highlight reads from memory. */
4568 if (RDG_MEM_READS_STMT (rdg, i))
4569 fprintf (file, "%d [style=filled, fillcolor=green]\n", i);
4571 /* Highlight stores to memory. */
4572 if (RDG_MEM_WRITE_STMT (rdg, i))
4573 fprintf (file, "%d [style=filled, fillcolor=red]\n", i);
4576 for (e = v->succ; e; e = e->succ_next)
4577 switch (RDGE_TYPE (e))
4580 fprintf (file, "%d -> %d [label=input] \n", i, e->dest);
4584 fprintf (file, "%d -> %d [label=output] \n", i, e->dest);
4588 /* These are the most common dependences: don't print these. */
4589 fprintf (file, "%d -> %d \n", i, e->dest);
4593 fprintf (file, "%d -> %d [label=anti] \n", i, e->dest);
4601 fprintf (file, "}\n\n");
4604 /* Display SCOP using dotty. */
4607 dot_rdg (struct graph *rdg)
4609 FILE *file = fopen ("/tmp/rdg.dot", "w");
4610 gcc_assert (file != NULL);
4612 dot_rdg_1 (file, rdg);
4615 system ("dotty /tmp/rdg.dot");
4619 /* This structure is used for recording the mapping statement index in
4622 struct rdg_vertex_info GTY(())
4628 /* Returns the index of STMT in RDG. */
4631 rdg_vertex_for_stmt (struct graph *rdg, gimple stmt)
4633 struct rdg_vertex_info rvi, *slot;
4636 slot = (struct rdg_vertex_info *) htab_find (rdg->indices, &rvi);
4644 /* Creates an edge in RDG for each distance vector from DDR. The
4645 order that we keep track of in the RDG is the order in which
4646 statements have to be executed. */
4649 create_rdg_edge_for_ddr (struct graph *rdg, ddr_p ddr)
4651 struct graph_edge *e;
4653 data_reference_p dra = DDR_A (ddr);
4654 data_reference_p drb = DDR_B (ddr);
4655 unsigned level = ddr_dependence_level (ddr);
4657 /* For non scalar dependences, when the dependence is REVERSED,
4658 statement B has to be executed before statement A. */
4660 && !DDR_REVERSED_P (ddr))
4662 data_reference_p tmp = dra;
4667 va = rdg_vertex_for_stmt (rdg, DR_STMT (dra));
4668 vb = rdg_vertex_for_stmt (rdg, DR_STMT (drb));
4670 if (va < 0 || vb < 0)
4673 e = add_edge (rdg, va, vb);
4674 e->data = XNEW (struct rdg_edge);
4676 RDGE_LEVEL (e) = level;
4677 RDGE_RELATION (e) = ddr;
4679 /* Determines the type of the data dependence. */
4680 if (DR_IS_READ (dra) && DR_IS_READ (drb))
4681 RDGE_TYPE (e) = input_dd;
4682 else if (!DR_IS_READ (dra) && !DR_IS_READ (drb))
4683 RDGE_TYPE (e) = output_dd;
4684 else if (!DR_IS_READ (dra) && DR_IS_READ (drb))
4685 RDGE_TYPE (e) = flow_dd;
4686 else if (DR_IS_READ (dra) && !DR_IS_READ (drb))
4687 RDGE_TYPE (e) = anti_dd;
4690 /* Creates dependence edges in RDG for all the uses of DEF. IDEF is
4691 the index of DEF in RDG. */
4694 create_rdg_edges_for_scalar (struct graph *rdg, tree def, int idef)
4696 use_operand_p imm_use_p;
4697 imm_use_iterator iterator;
4699 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, def)
4701 struct graph_edge *e;
4702 int use = rdg_vertex_for_stmt (rdg, USE_STMT (imm_use_p));
4707 e = add_edge (rdg, idef, use);
4708 e->data = XNEW (struct rdg_edge);
4709 RDGE_TYPE (e) = flow_dd;
4710 RDGE_RELATION (e) = NULL;
4714 /* Creates the edges of the reduced dependence graph RDG. */
4717 create_rdg_edges (struct graph *rdg, VEC (ddr_p, heap) *ddrs)
4720 struct data_dependence_relation *ddr;
4721 def_operand_p def_p;
4724 for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++)
4725 if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE)
4726 create_rdg_edge_for_ddr (rdg, ddr);
4728 for (i = 0; i < rdg->n_vertices; i++)
4729 FOR_EACH_PHI_OR_STMT_DEF (def_p, RDG_STMT (rdg, i),
4731 create_rdg_edges_for_scalar (rdg, DEF_FROM_PTR (def_p), i);
4734 /* Build the vertices of the reduced dependence graph RDG. */
4737 create_rdg_vertices (struct graph *rdg, VEC (gimple, heap) *stmts)
4742 for (i = 0; VEC_iterate (gimple, stmts, i, stmt); i++)
4744 VEC (data_ref_loc, heap) *references;
4746 struct vertex *v = &(rdg->vertices[i]);
4747 struct rdg_vertex_info *rvi = XNEW (struct rdg_vertex_info);
4748 struct rdg_vertex_info **slot;
4752 slot = (struct rdg_vertex_info **) htab_find_slot (rdg->indices, rvi, INSERT);
4759 v->data = XNEW (struct rdg_vertex);
4760 RDG_STMT (rdg, i) = stmt;
4762 RDG_MEM_WRITE_STMT (rdg, i) = false;
4763 RDG_MEM_READS_STMT (rdg, i) = false;
4764 if (gimple_code (stmt) == GIMPLE_PHI)
4767 get_references_in_stmt (stmt, &references);
4768 for (j = 0; VEC_iterate (data_ref_loc, references, j, ref); j++)
4770 RDG_MEM_WRITE_STMT (rdg, i) = true;
4772 RDG_MEM_READS_STMT (rdg, i) = true;
4774 VEC_free (data_ref_loc, heap, references);
4778 /* Initialize STMTS with all the statements of LOOP. When
4779 INCLUDE_PHIS is true, include also the PHI nodes. The order in
4780 which we discover statements is important as
4781 generate_loops_for_partition is using the same traversal for
4782 identifying statements. */
4785 stmts_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4788 basic_block *bbs = get_loop_body_in_dom_order (loop);
4790 for (i = 0; i < loop->num_nodes; i++)
4792 basic_block bb = bbs[i];
4793 gimple_stmt_iterator bsi;
4796 for (bsi = gsi_start_phis (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4797 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4799 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4801 stmt = gsi_stmt (bsi);
4802 if (gimple_code (stmt) != GIMPLE_LABEL)
4803 VEC_safe_push (gimple, heap, *stmts, stmt);
4810 /* Returns true when all the dependences are computable. */
4813 known_dependences_p (VEC (ddr_p, heap) *dependence_relations)
4818 for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++)
4819 if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know)
4825 /* Computes a hash function for element ELT. */
4828 hash_stmt_vertex_info (const void *elt)
4830 const struct rdg_vertex_info *const rvi =
4831 (const struct rdg_vertex_info *) elt;
4832 gimple stmt = rvi->stmt;
4834 return htab_hash_pointer (stmt);
4837 /* Compares database elements E1 and E2. */
4840 eq_stmt_vertex_info (const void *e1, const void *e2)
4842 const struct rdg_vertex_info *elt1 = (const struct rdg_vertex_info *) e1;
4843 const struct rdg_vertex_info *elt2 = (const struct rdg_vertex_info *) e2;
4845 return elt1->stmt == elt2->stmt;
4848 /* Free the element E. */
4851 hash_stmt_vertex_del (void *e)
4856 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4857 statement of the loop nest, and one edge per data dependence or
4858 scalar dependence. */
4861 build_empty_rdg (int n_stmts)
4863 int nb_data_refs = 10;
4864 struct graph *rdg = new_graph (n_stmts);
4866 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4867 eq_stmt_vertex_info, hash_stmt_vertex_del);
4871 /* Build the Reduced Dependence Graph (RDG) with one vertex per
4872 statement of the loop nest, and one edge per data dependence or
4873 scalar dependence. */
4876 build_rdg (struct loop *loop)
4878 int nb_data_refs = 10;
4879 struct graph *rdg = NULL;
4880 VEC (ddr_p, heap) *dependence_relations;
4881 VEC (data_reference_p, heap) *datarefs;
4882 VEC (gimple, heap) *stmts = VEC_alloc (gimple, heap, nb_data_refs);
4884 dependence_relations = VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs) ;
4885 datarefs = VEC_alloc (data_reference_p, heap, nb_data_refs);
4886 compute_data_dependences_for_loop (loop,
4889 &dependence_relations);
4891 if (!known_dependences_p (dependence_relations))
4893 free_dependence_relations (dependence_relations);
4894 free_data_refs (datarefs);
4895 VEC_free (gimple, heap, stmts);
4900 stmts_from_loop (loop, &stmts);
4901 rdg = build_empty_rdg (VEC_length (gimple, stmts));
4903 rdg->indices = htab_create (nb_data_refs, hash_stmt_vertex_info,
4904 eq_stmt_vertex_info, hash_stmt_vertex_del);
4905 create_rdg_vertices (rdg, stmts);
4906 create_rdg_edges (rdg, dependence_relations);
4908 VEC_free (gimple, heap, stmts);
4912 /* Free the reduced dependence graph RDG. */
4915 free_rdg (struct graph *rdg)
4919 for (i = 0; i < rdg->n_vertices; i++)
4920 free (rdg->vertices[i].data);
4922 htab_delete (rdg->indices);
4926 /* Initialize STMTS with all the statements of LOOP that contain a
4930 stores_from_loop (struct loop *loop, VEC (gimple, heap) **stmts)
4933 basic_block *bbs = get_loop_body_in_dom_order (loop);
4935 for (i = 0; i < loop->num_nodes; i++)
4937 basic_block bb = bbs[i];
4938 gimple_stmt_iterator bsi;
4940 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
4941 if (!ZERO_SSA_OPERANDS (gsi_stmt (bsi), SSA_OP_VDEF))
4942 VEC_safe_push (gimple, heap, *stmts, gsi_stmt (bsi));
4948 /* For a data reference REF, return the declaration of its base
4949 address or NULL_TREE if the base is not determined. */
4952 ref_base_address (gimple stmt, data_ref_loc *ref)
4954 tree base = NULL_TREE;
4956 struct data_reference *dr = XCNEW (struct data_reference);
4958 DR_STMT (dr) = stmt;
4959 DR_REF (dr) = *ref->pos;
4960 dr_analyze_innermost (dr);
4961 base_address = DR_BASE_ADDRESS (dr);
4966 switch (TREE_CODE (base_address))
4969 base = TREE_OPERAND (base_address, 0);
4973 base = base_address;
4982 /* Determines whether the statement from vertex V of the RDG has a
4983 definition used outside the loop that contains this statement. */
4986 rdg_defs_used_in_other_loops_p (struct graph *rdg, int v)
4988 gimple stmt = RDG_STMT (rdg, v);
4989 struct loop *loop = loop_containing_stmt (stmt);
4990 use_operand_p imm_use_p;
4991 imm_use_iterator iterator;
4993 def_operand_p def_p;
4998 FOR_EACH_PHI_OR_STMT_DEF (def_p, stmt, it, SSA_OP_DEF)
5000 FOR_EACH_IMM_USE_FAST (imm_use_p, iterator, DEF_FROM_PTR (def_p))
5002 if (loop_containing_stmt (USE_STMT (imm_use_p)) != loop)
5010 /* Determines whether statements S1 and S2 access to similar memory
5011 locations. Two memory accesses are considered similar when they
5012 have the same base address declaration, i.e. when their
5013 ref_base_address is the same. */
5016 have_similar_memory_accesses (gimple s1, gimple s2)
5020 VEC (data_ref_loc, heap) *refs1, *refs2;
5021 data_ref_loc *ref1, *ref2;
5023 get_references_in_stmt (s1, &refs1);
5024 get_references_in_stmt (s2, &refs2);
5026 for (i = 0; VEC_iterate (data_ref_loc, refs1, i, ref1); i++)
5028 tree base1 = ref_base_address (s1, ref1);
5031 for (j = 0; VEC_iterate (data_ref_loc, refs2, j, ref2); j++)
5032 if (base1 == ref_base_address (s2, ref2))
5040 VEC_free (data_ref_loc, heap, refs1);
5041 VEC_free (data_ref_loc, heap, refs2);
5045 /* Helper function for the hashtab. */
5048 have_similar_memory_accesses_1 (const void *s1, const void *s2)
5050 return have_similar_memory_accesses (CONST_CAST_GIMPLE ((const_gimple) s1),
5051 CONST_CAST_GIMPLE ((const_gimple) s2));
5054 /* Helper function for the hashtab. */
5057 ref_base_address_1 (const void *s)
5059 gimple stmt = CONST_CAST_GIMPLE ((const_gimple) s);
5061 VEC (data_ref_loc, heap) *refs;
5065 get_references_in_stmt (stmt, &refs);
5067 for (i = 0; VEC_iterate (data_ref_loc, refs, i, ref); i++)
5070 res = htab_hash_pointer (ref_base_address (stmt, ref));
5074 VEC_free (data_ref_loc, heap, refs);
5078 /* Try to remove duplicated write data references from STMTS. */
5081 remove_similar_memory_refs (VEC (gimple, heap) **stmts)
5085 htab_t seen = htab_create (VEC_length (gimple, *stmts), ref_base_address_1,
5086 have_similar_memory_accesses_1, NULL);
5088 for (i = 0; VEC_iterate (gimple, *stmts, i, stmt); )
5092 slot = htab_find_slot (seen, stmt, INSERT);
5095 VEC_ordered_remove (gimple, *stmts, i);
5098 *slot = (void *) stmt;
5106 /* Returns the index of PARAMETER in the parameters vector of the
5107 ACCESS_MATRIX. If PARAMETER does not exist return -1. */
5110 access_matrix_get_index_for_parameter (tree parameter,
5111 struct access_matrix *access_matrix)
5114 VEC (tree,heap) *lambda_parameters = AM_PARAMETERS (access_matrix);
5115 tree lambda_parameter;
5117 for (i = 0; VEC_iterate (tree, lambda_parameters, i, lambda_parameter); i++)
5118 if (lambda_parameter == parameter)
5119 return i + AM_NB_INDUCTION_VARS (access_matrix);