diff options
Diffstat (limited to 'gcc/tree-data-ref.c')
| -rw-r--r-- | gcc/tree-data-ref.c | 6386 |
1 files changed, 0 insertions, 6386 deletions
diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c deleted file mode 100644 index 397792c..0000000 --- a/gcc/tree-data-ref.c +++ /dev/null @@ -1,6386 +0,0 @@ -/* Data references and dependences detectors. - Copyright (C) 2003-2022 Free Software Foundation, Inc. - Contributed by Sebastian Pop <pop@cri.ensmp.fr> - -This file is part of GCC. - -GCC is free software; you can redistribute it and/or modify it under -the terms of the GNU General Public License as published by the Free -Software Foundation; either version 3, or (at your option) any later -version. - -GCC is distributed in the hope that it will be useful, but WITHOUT ANY -WARRANTY; without even the implied warranty of MERCHANTABILITY or -FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -for more details. - -You should have received a copy of the GNU General Public License -along with GCC; see the file COPYING3. If not see -<http://www.gnu.org/licenses/>. */ - -/* This pass walks a given loop structure searching for array - references. The information about the array accesses is recorded - in DATA_REFERENCE structures. - - The basic test for determining the dependences is: - given two access functions chrec1 and chrec2 to a same array, and - x and y two vectors from the iteration domain, the same element of - the array is accessed twice at iterations x and y if and only if: - | chrec1 (x) == chrec2 (y). - - The goals of this analysis are: - - - to determine the independence: the relation between two - independent accesses is qualified with the chrec_known (this - information allows a loop parallelization), - - - when two data references access the same data, to qualify the - dependence relation with classic dependence representations: - - - distance vectors - - direction vectors - - loop carried level dependence - - polyhedron dependence - or with the chains of recurrences based representation, - - - to define a knowledge base for storing the data dependence - information, - - - to define an interface to access this data. - - - Definitions: - - - subscript: given two array accesses a subscript is the tuple - composed of the access functions for a given dimension. Example: - Given A[f1][f2][f3] and B[g1][g2][g3], there are three subscripts: - (f1, g1), (f2, g2), (f3, g3). - - - Diophantine equation: an equation whose coefficients and - solutions are integer constants, for example the equation - | 3*x + 2*y = 1 - has an integer solution x = 1 and y = -1. - - References: - - - "Advanced Compilation for High Performance Computing" by Randy - Allen and Ken Kennedy. - http://citeseer.ist.psu.edu/goff91practical.html - - - "Loop Transformations for Restructuring Compilers - The Foundations" - by Utpal Banerjee. - - -*/ - -#include "config.h" -#include "system.h" -#include "coretypes.h" -#include "backend.h" -#include "rtl.h" -#include "tree.h" -#include "gimple.h" -#include "gimple-pretty-print.h" -#include "alias.h" -#include "fold-const.h" -#include "expr.h" -#include "gimple-iterator.h" -#include "tree-ssa-loop-niter.h" -#include "tree-ssa-loop.h" -#include "tree-ssa.h" -#include "cfgloop.h" -#include "tree-data-ref.h" -#include "tree-scalar-evolution.h" -#include "dumpfile.h" -#include "tree-affine.h" -#include "builtins.h" -#include "tree-eh.h" -#include "ssa.h" -#include "internal-fn.h" -#include "vr-values.h" -#include "range-op.h" -#include "tree-ssa-loop-ivopts.h" - -static struct datadep_stats -{ - int num_dependence_tests; - int num_dependence_dependent; - int num_dependence_independent; - int num_dependence_undetermined; - - int num_subscript_tests; - int num_subscript_undetermined; - int num_same_subscript_function; - - int num_ziv; - int num_ziv_independent; - int num_ziv_dependent; - int num_ziv_unimplemented; - - int num_siv; - int num_siv_independent; - int num_siv_dependent; - int num_siv_unimplemented; - - int num_miv; - int num_miv_independent; - int num_miv_dependent; - int num_miv_unimplemented; -} dependence_stats; - -static bool subscript_dependence_tester_1 (struct data_dependence_relation *, - unsigned int, unsigned int, - class loop *); -/* Returns true iff A divides B. */ - -static inline bool -tree_fold_divides_p (const_tree a, const_tree b) -{ - gcc_assert (TREE_CODE (a) == INTEGER_CST); - gcc_assert (TREE_CODE (b) == INTEGER_CST); - return integer_zerop (int_const_binop (TRUNC_MOD_EXPR, b, a)); -} - -/* Returns true iff A divides B. */ - -static inline bool -int_divides_p (lambda_int a, lambda_int b) -{ - return ((b % a) == 0); -} - -/* Return true if reference REF contains a union access. */ - -static bool -ref_contains_union_access_p (tree ref) -{ - while (handled_component_p (ref)) - { - ref = TREE_OPERAND (ref, 0); - if (TREE_CODE (TREE_TYPE (ref)) == UNION_TYPE - || TREE_CODE (TREE_TYPE (ref)) == QUAL_UNION_TYPE) - return true; - } - return false; -} - - - -/* Dump into FILE all the data references from DATAREFS. */ - -static void -dump_data_references (FILE *file, vec<data_reference_p> datarefs) -{ - for (data_reference *dr : datarefs) - dump_data_reference (file, dr); -} - -/* Unified dump into FILE all the data references from DATAREFS. */ - -DEBUG_FUNCTION void -debug (vec<data_reference_p> &ref) -{ - dump_data_references (stderr, ref); -} - -DEBUG_FUNCTION void -debug (vec<data_reference_p> *ptr) -{ - if (ptr) - debug (*ptr); - else - fprintf (stderr, "<nil>\n"); -} - - -/* Dump into STDERR all the data references from DATAREFS. */ - -DEBUG_FUNCTION void -debug_data_references (vec<data_reference_p> datarefs) -{ - dump_data_references (stderr, datarefs); -} - -/* Print to STDERR the data_reference DR. */ - -DEBUG_FUNCTION void -debug_data_reference (struct data_reference *dr) -{ - dump_data_reference (stderr, dr); -} - -/* Dump function for a DATA_REFERENCE structure. */ - -void -dump_data_reference (FILE *outf, - struct data_reference *dr) -{ - unsigned int i; - - fprintf (outf, "#(Data Ref: \n"); - fprintf (outf, "# bb: %d \n", gimple_bb (DR_STMT (dr))->index); - fprintf (outf, "# stmt: "); - print_gimple_stmt (outf, DR_STMT (dr), 0); - fprintf (outf, "# ref: "); - print_generic_stmt (outf, DR_REF (dr)); - fprintf (outf, "# base_object: "); - print_generic_stmt (outf, DR_BASE_OBJECT (dr)); - - for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++) - { - fprintf (outf, "# Access function %d: ", i); - print_generic_stmt (outf, DR_ACCESS_FN (dr, i)); - } - fprintf (outf, "#)\n"); -} - -/* Unified dump function for a DATA_REFERENCE structure. */ - -DEBUG_FUNCTION void -debug (data_reference &ref) -{ - dump_data_reference (stderr, &ref); -} - -DEBUG_FUNCTION void -debug (data_reference *ptr) -{ - if (ptr) - debug (*ptr); - else - fprintf (stderr, "<nil>\n"); -} - - -/* Dumps the affine function described by FN to the file OUTF. */ - -DEBUG_FUNCTION void -dump_affine_function (FILE *outf, affine_fn fn) -{ - unsigned i; - tree coef; - - print_generic_expr (outf, fn[0], TDF_SLIM); - for (i = 1; fn.iterate (i, &coef); i++) - { - fprintf (outf, " + "); - print_generic_expr (outf, coef, TDF_SLIM); - fprintf (outf, " * x_%u", i); - } -} - -/* Dumps the conflict function CF to the file OUTF. */ - -DEBUG_FUNCTION void -dump_conflict_function (FILE *outf, conflict_function *cf) -{ - unsigned i; - - if (cf->n == NO_DEPENDENCE) - fprintf (outf, "no dependence"); - else if (cf->n == NOT_KNOWN) - fprintf (outf, "not known"); - else - { - for (i = 0; i < cf->n; i++) - { - if (i != 0) - fprintf (outf, " "); - fprintf (outf, "["); - dump_affine_function (outf, cf->fns[i]); - fprintf (outf, "]"); - } - } -} - -/* Dump function for a SUBSCRIPT structure. */ - -DEBUG_FUNCTION void -dump_subscript (FILE *outf, struct subscript *subscript) -{ - conflict_function *cf = SUB_CONFLICTS_IN_A (subscript); - - fprintf (outf, "\n (subscript \n"); - fprintf (outf, " iterations_that_access_an_element_twice_in_A: "); - dump_conflict_function (outf, cf); - if (CF_NONTRIVIAL_P (cf)) - { - tree last_iteration = SUB_LAST_CONFLICT (subscript); - fprintf (outf, "\n last_conflict: "); - print_generic_expr (outf, last_iteration); - } - - cf = SUB_CONFLICTS_IN_B (subscript); - fprintf (outf, "\n iterations_that_access_an_element_twice_in_B: "); - dump_conflict_function (outf, cf); - if (CF_NONTRIVIAL_P (cf)) - { - tree last_iteration = SUB_LAST_CONFLICT (subscript); - fprintf (outf, "\n last_conflict: "); - print_generic_expr (outf, last_iteration); - } - - fprintf (outf, "\n (Subscript distance: "); - print_generic_expr (outf, SUB_DISTANCE (subscript)); - fprintf (outf, " ))\n"); -} - -/* Print the classic direction vector DIRV to OUTF. */ - -DEBUG_FUNCTION void -print_direction_vector (FILE *outf, - lambda_vector dirv, - int length) -{ - int eq; - - for (eq = 0; eq < length; eq++) - { - enum data_dependence_direction dir = ((enum data_dependence_direction) - dirv[eq]); - - switch (dir) - { - case dir_positive: - fprintf (outf, " +"); - break; - case dir_negative: - fprintf (outf, " -"); - break; - case dir_equal: - fprintf (outf, " ="); - break; - case dir_positive_or_equal: - fprintf (outf, " +="); - break; - case dir_positive_or_negative: - fprintf (outf, " +-"); - break; - case dir_negative_or_equal: - fprintf (outf, " -="); - break; - case dir_star: - fprintf (outf, " *"); - break; - default: - fprintf (outf, "indep"); - break; - } - } - fprintf (outf, "\n"); -} - -/* Print a vector of direction vectors. */ - -DEBUG_FUNCTION void -print_dir_vectors (FILE *outf, vec<lambda_vector> dir_vects, - int length) -{ - for (lambda_vector v : dir_vects) - print_direction_vector (outf, v, length); -} - -/* Print out a vector VEC of length N to OUTFILE. */ - -DEBUG_FUNCTION void -print_lambda_vector (FILE * outfile, lambda_vector vector, int n) -{ - int i; - - for (i = 0; i < n; i++) - fprintf (outfile, HOST_WIDE_INT_PRINT_DEC " ", vector[i]); - fprintf (outfile, "\n"); -} - -/* Print a vector of distance vectors. */ - -DEBUG_FUNCTION void -print_dist_vectors (FILE *outf, vec<lambda_vector> dist_vects, - int length) -{ - for (lambda_vector v : dist_vects) - print_lambda_vector (outf, v, length); -} - -/* Dump function for a DATA_DEPENDENCE_RELATION structure. */ - -DEBUG_FUNCTION void -dump_data_dependence_relation (FILE *outf, const data_dependence_relation *ddr) -{ - struct data_reference *dra, *drb; - - fprintf (outf, "(Data Dep: \n"); - - if (!ddr || DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) - { - if (ddr) - { - dra = DDR_A (ddr); - drb = DDR_B (ddr); - if (dra) - dump_data_reference (outf, dra); - else - fprintf (outf, " (nil)\n"); - if (drb) - dump_data_reference (outf, drb); - else - fprintf (outf, " (nil)\n"); - } - fprintf (outf, " (don't know)\n)\n"); - return; - } - - dra = DDR_A (ddr); - drb = DDR_B (ddr); - dump_data_reference (outf, dra); - dump_data_reference (outf, drb); - - if (DDR_ARE_DEPENDENT (ddr) == chrec_known) - fprintf (outf, " (no dependence)\n"); - - else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) - { - unsigned int i; - class loop *loopi; - - subscript *sub; - FOR_EACH_VEC_ELT (DDR_SUBSCRIPTS (ddr), i, sub) - { - fprintf (outf, " access_fn_A: "); - print_generic_stmt (outf, SUB_ACCESS_FN (sub, 0)); - fprintf (outf, " access_fn_B: "); - print_generic_stmt (outf, SUB_ACCESS_FN (sub, 1)); - dump_subscript (outf, sub); - } - - fprintf (outf, " loop nest: ("); - FOR_EACH_VEC_ELT (DDR_LOOP_NEST (ddr), i, loopi) - fprintf (outf, "%d ", loopi->num); - fprintf (outf, ")\n"); - - for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++) - { - fprintf (outf, " distance_vector: "); - print_lambda_vector (outf, DDR_DIST_VECT (ddr, i), - DDR_NB_LOOPS (ddr)); - } - - for (i = 0; i < DDR_NUM_DIR_VECTS (ddr); i++) - { - fprintf (outf, " direction_vector: "); - print_direction_vector (outf, DDR_DIR_VECT (ddr, i), - DDR_NB_LOOPS (ddr)); - } - } - - fprintf (outf, ")\n"); -} - -/* Debug version. */ - -DEBUG_FUNCTION void -debug_data_dependence_relation (const struct data_dependence_relation *ddr) -{ - dump_data_dependence_relation (stderr, ddr); -} - -/* Dump into FILE all the dependence relations from DDRS. */ - -DEBUG_FUNCTION void -dump_data_dependence_relations (FILE *file, const vec<ddr_p> &ddrs) -{ - for (auto ddr : ddrs) - dump_data_dependence_relation (file, ddr); -} - -DEBUG_FUNCTION void -debug (vec<ddr_p> &ref) -{ - dump_data_dependence_relations (stderr, ref); -} - -DEBUG_FUNCTION void -debug (vec<ddr_p> *ptr) -{ - if (ptr) - debug (*ptr); - else - fprintf (stderr, "<nil>\n"); -} - - -/* Dump to STDERR all the dependence relations from DDRS. */ - -DEBUG_FUNCTION void -debug_data_dependence_relations (vec<ddr_p> ddrs) -{ - dump_data_dependence_relations (stderr, ddrs); -} - -/* Dumps the distance and direction vectors in FILE. DDRS contains - the dependence relations, and VECT_SIZE is the size of the - dependence vectors, or in other words the number of loops in the - considered nest. */ - -DEBUG_FUNCTION void -dump_dist_dir_vectors (FILE *file, vec<ddr_p> ddrs) -{ - for (data_dependence_relation *ddr : ddrs) - if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE && DDR_AFFINE_P (ddr)) - { - for (lambda_vector v : DDR_DIST_VECTS (ddr)) - { - fprintf (file, "DISTANCE_V ("); - print_lambda_vector (file, v, DDR_NB_LOOPS (ddr)); - fprintf (file, ")\n"); - } - - for (lambda_vector v : DDR_DIR_VECTS (ddr)) - { - fprintf (file, "DIRECTION_V ("); - print_direction_vector (file, v, DDR_NB_LOOPS (ddr)); - fprintf (file, ")\n"); - } - } - - fprintf (file, "\n\n"); -} - -/* Dumps the data dependence relations DDRS in FILE. */ - -DEBUG_FUNCTION void -dump_ddrs (FILE *file, vec<ddr_p> ddrs) -{ - for (data_dependence_relation *ddr : ddrs) - dump_data_dependence_relation (file, ddr); - - fprintf (file, "\n\n"); -} - -DEBUG_FUNCTION void -debug_ddrs (vec<ddr_p> ddrs) -{ - dump_ddrs (stderr, ddrs); -} - -/* If RESULT_RANGE is nonnull, set *RESULT_RANGE to the range of - OP0 CODE OP1, where: - - - OP0 CODE OP1 has integral type TYPE - - the range of OP0 is given by OP0_RANGE and - - the range of OP1 is given by OP1_RANGE. - - Independently of RESULT_RANGE, try to compute: - - DELTA = ((sizetype) OP0 CODE (sizetype) OP1) - - (sizetype) (OP0 CODE OP1) - - as a constant and subtract DELTA from the ssizetype constant in *OFF. - Return true on success, or false if DELTA is not known at compile time. - - Truncation and sign changes are known to distribute over CODE, i.e. - - (itype) (A CODE B) == (itype) A CODE (itype) B - - for any integral type ITYPE whose precision is no greater than the - precision of A and B. */ - -static bool -compute_distributive_range (tree type, value_range &op0_range, - tree_code code, value_range &op1_range, - tree *off, value_range *result_range) -{ - gcc_assert (INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_TRAPS (type)); - if (result_range) - { - range_operator *op = range_op_handler (code, type); - op->fold_range (*result_range, type, op0_range, op1_range); - } - - /* The distributive property guarantees that if TYPE is no narrower - than SIZETYPE, - - (sizetype) (OP0 CODE OP1) == (sizetype) OP0 CODE (sizetype) OP1 - - and so we can treat DELTA as zero. */ - if (TYPE_PRECISION (type) >= TYPE_PRECISION (sizetype)) - return true; - - /* If overflow is undefined, we can assume that: - - X == (ssizetype) OP0 CODE (ssizetype) OP1 - - is within the range of TYPE, i.e.: - - X == (ssizetype) (TYPE) X - - Distributing the (TYPE) truncation over X gives: - - X == (ssizetype) (OP0 CODE OP1) - - Casting both sides to sizetype and distributing the sizetype cast - over X gives: - - (sizetype) OP0 CODE (sizetype) OP1 == (sizetype) (OP0 CODE OP1) - - and so we can treat DELTA as zero. */ - if (TYPE_OVERFLOW_UNDEFINED (type)) - return true; - - /* Compute the range of: - - (ssizetype) OP0 CODE (ssizetype) OP1 - - The distributive property guarantees that this has the same bitpattern as: - - (sizetype) OP0 CODE (sizetype) OP1 - - but its range is more conducive to analysis. */ - range_cast (op0_range, ssizetype); - range_cast (op1_range, ssizetype); - value_range wide_range; - range_operator *op = range_op_handler (code, ssizetype); - bool saved_flag_wrapv = flag_wrapv; - flag_wrapv = 1; - op->fold_range (wide_range, ssizetype, op0_range, op1_range); - flag_wrapv = saved_flag_wrapv; - if (wide_range.num_pairs () != 1 || !range_int_cst_p (&wide_range)) - return false; - - wide_int lb = wide_range.lower_bound (); - wide_int ub = wide_range.upper_bound (); - - /* Calculate the number of times that each end of the range overflows or - underflows TYPE. We can only calculate DELTA if the numbers match. */ - unsigned int precision = TYPE_PRECISION (type); - if (!TYPE_UNSIGNED (type)) - { - wide_int type_min = wi::mask (precision - 1, true, lb.get_precision ()); - lb -= type_min; - ub -= type_min; - } - wide_int upper_bits = wi::mask (precision, true, lb.get_precision ()); - lb &= upper_bits; - ub &= upper_bits; - if (lb != ub) - return false; - - /* OP0 CODE OP1 overflows exactly arshift (LB, PRECISION) times, with - negative values indicating underflow. The low PRECISION bits of LB - are clear, so DELTA is therefore LB (== UB). */ - *off = wide_int_to_tree (ssizetype, wi::to_wide (*off) - lb); - return true; -} - -/* Return true if (sizetype) OP == (sizetype) (TO_TYPE) OP, - given that OP has type FROM_TYPE and range RANGE. Both TO_TYPE and - FROM_TYPE are integral types. */ - -static bool -nop_conversion_for_offset_p (tree to_type, tree from_type, value_range &range) -{ - gcc_assert (INTEGRAL_TYPE_P (to_type) - && INTEGRAL_TYPE_P (from_type) - && !TYPE_OVERFLOW_TRAPS (to_type) - && !TYPE_OVERFLOW_TRAPS (from_type)); - - /* Converting to something no narrower than sizetype and then to sizetype - is equivalent to converting directly to sizetype. */ - if (TYPE_PRECISION (to_type) >= TYPE_PRECISION (sizetype)) - return true; - - /* Check whether TO_TYPE can represent all values that FROM_TYPE can. */ - if (TYPE_PRECISION (from_type) < TYPE_PRECISION (to_type) - && (TYPE_UNSIGNED (from_type) || !TYPE_UNSIGNED (to_type))) - return true; - - /* For narrowing conversions, we could in principle test whether - the bits in FROM_TYPE but not in TO_TYPE have a fixed value - and apply a constant adjustment. - - For other conversions (which involve a sign change) we could - check that the signs are always equal, and apply a constant - adjustment if the signs are negative. - - However, both cases should be rare. */ - return range_fits_type_p (&range, TYPE_PRECISION (to_type), - TYPE_SIGN (to_type)); -} - -static void -split_constant_offset (tree type, tree *var, tree *off, - value_range *result_range, - hash_map<tree, std::pair<tree, tree> > &cache, - unsigned *limit); - -/* Helper function for split_constant_offset. If TYPE is a pointer type, - try to express OP0 CODE OP1 as: - - POINTER_PLUS <*VAR, (sizetype) *OFF> - - where: - - - *VAR has type TYPE - - *OFF is a constant of type ssizetype. - - If TYPE is an integral type, try to express (sizetype) (OP0 CODE OP1) as: - - *VAR + (sizetype) *OFF - - where: - - - *VAR has type sizetype - - *OFF is a constant of type ssizetype. - - In both cases, OP0 CODE OP1 has type TYPE. - - Return true on success. A false return value indicates that we can't - do better than set *OFF to zero. - - When returning true, set RESULT_RANGE to the range of OP0 CODE OP1, - if RESULT_RANGE is nonnull and if we can do better than assume VR_VARYING. - - CACHE caches {*VAR, *OFF} pairs for SSA names that we've previously - visited. LIMIT counts down the number of SSA names that we are - allowed to process before giving up. */ - -static bool -split_constant_offset_1 (tree type, tree op0, enum tree_code code, tree op1, - tree *var, tree *off, value_range *result_range, - hash_map<tree, std::pair<tree, tree> > &cache, - unsigned *limit) -{ - tree var0, var1; - tree off0, off1; - value_range op0_range, op1_range; - - *var = NULL_TREE; - *off = NULL_TREE; - - if (INTEGRAL_TYPE_P (type) && TYPE_OVERFLOW_TRAPS (type)) - return false; - - switch (code) - { - case INTEGER_CST: - *var = size_int (0); - *off = fold_convert (ssizetype, op0); - if (result_range) - result_range->set (op0, op0); - return true; - - case POINTER_PLUS_EXPR: - split_constant_offset (op0, &var0, &off0, nullptr, cache, limit); - split_constant_offset (op1, &var1, &off1, nullptr, cache, limit); - *var = fold_build2 (POINTER_PLUS_EXPR, type, var0, var1); - *off = size_binop (PLUS_EXPR, off0, off1); - return true; - - case PLUS_EXPR: - case MINUS_EXPR: - split_constant_offset (op0, &var0, &off0, &op0_range, cache, limit); - split_constant_offset (op1, &var1, &off1, &op1_range, cache, limit); - *off = size_binop (code, off0, off1); - if (!compute_distributive_range (type, op0_range, code, op1_range, - off, result_range)) - return false; - *var = fold_build2 (code, sizetype, var0, var1); - return true; - - case MULT_EXPR: - if (TREE_CODE (op1) != INTEGER_CST) - return false; - - split_constant_offset (op0, &var0, &off0, &op0_range, cache, limit); - op1_range.set (op1, op1); - *off = size_binop (MULT_EXPR, off0, fold_convert (ssizetype, op1)); - if (!compute_distributive_range (type, op0_range, code, op1_range, - off, result_range)) - return false; - *var = fold_build2 (MULT_EXPR, sizetype, var0, - fold_convert (sizetype, op1)); - return true; - - case ADDR_EXPR: - { - tree base, poffset; - poly_int64 pbitsize, pbitpos, pbytepos; - machine_mode pmode; - int punsignedp, preversep, pvolatilep; - - op0 = TREE_OPERAND (op0, 0); - base - = get_inner_reference (op0, &pbitsize, &pbitpos, &poffset, &pmode, - &punsignedp, &preversep, &pvolatilep); - - if (!multiple_p (pbitpos, BITS_PER_UNIT, &pbytepos)) - return false; - base = build_fold_addr_expr (base); - off0 = ssize_int (pbytepos); - - if (poffset) - { - split_constant_offset (poffset, &poffset, &off1, nullptr, - cache, limit); - off0 = size_binop (PLUS_EXPR, off0, off1); - base = fold_build_pointer_plus (base, poffset); - } - - var0 = fold_convert (type, base); - - /* If variable length types are involved, punt, otherwise casts - might be converted into ARRAY_REFs in gimplify_conversion. - To compute that ARRAY_REF's element size TYPE_SIZE_UNIT, which - possibly no longer appears in current GIMPLE, might resurface. - This perhaps could run - if (CONVERT_EXPR_P (var0)) - { - gimplify_conversion (&var0); - // Attempt to fill in any within var0 found ARRAY_REF's - // element size from corresponding op embedded ARRAY_REF, - // if unsuccessful, just punt. - } */ - while (POINTER_TYPE_P (type)) - type = TREE_TYPE (type); - if (int_size_in_bytes (type) < 0) - return false; - - *var = var0; - *off = off0; - return true; - } - - case SSA_NAME: - { - if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op0)) - return false; - - gimple *def_stmt = SSA_NAME_DEF_STMT (op0); - enum tree_code subcode; - - if (gimple_code (def_stmt) != GIMPLE_ASSIGN) - return false; - - subcode = gimple_assign_rhs_code (def_stmt); - - /* We are using a cache to avoid un-CSEing large amounts of code. */ - bool use_cache = false; - if (!has_single_use (op0) - && (subcode == POINTER_PLUS_EXPR - || subcode == PLUS_EXPR - || subcode == MINUS_EXPR - || subcode == MULT_EXPR - || subcode == ADDR_EXPR - || CONVERT_EXPR_CODE_P (subcode))) - { - use_cache = true; - bool existed; - std::pair<tree, tree> &e = cache.get_or_insert (op0, &existed); - if (existed) - { - if (integer_zerop (e.second)) - return false; - *var = e.first; - *off = e.second; - /* The caller sets the range in this case. */ - return true; - } - e = std::make_pair (op0, ssize_int (0)); - } - - if (*limit == 0) - return false; - --*limit; - - var0 = gimple_assign_rhs1 (def_stmt); - var1 = gimple_assign_rhs2 (def_stmt); - - bool res = split_constant_offset_1 (type, var0, subcode, var1, - var, off, nullptr, cache, limit); - if (res && use_cache) - *cache.get (op0) = std::make_pair (*var, *off); - /* The caller sets the range in this case. */ - return res; - } - CASE_CONVERT: - { - /* We can only handle the following conversions: - - - Conversions from one pointer type to another pointer type. - - - Conversions from one non-trapping integral type to another - non-trapping integral type. In this case, the recursive - call makes sure that: - - (sizetype) OP0 - - can be expressed as a sizetype operation involving VAR and OFF, - and all we need to do is check whether: - - (sizetype) OP0 == (sizetype) (TYPE) OP0 - - - Conversions from a non-trapping sizetype-size integral type to - a like-sized pointer type. In this case, the recursive call - makes sure that: - - (sizetype) OP0 == *VAR + (sizetype) *OFF - - and we can convert that to: - - POINTER_PLUS <(TYPE) *VAR, (sizetype) *OFF> - - - Conversions from a sizetype-sized pointer type to a like-sized - non-trapping integral type. In this case, the recursive call - makes sure that: - - OP0 == POINTER_PLUS <*VAR, (sizetype) *OFF> - - where the POINTER_PLUS and *VAR have the same precision as - TYPE (and the same precision as sizetype). Then: - - (sizetype) (TYPE) OP0 == (sizetype) *VAR + (sizetype) *OFF. */ - tree itype = TREE_TYPE (op0); - if ((POINTER_TYPE_P (itype) - || (INTEGRAL_TYPE_P (itype) && !TYPE_OVERFLOW_TRAPS (itype))) - && (POINTER_TYPE_P (type) - || (INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_TRAPS (type))) - && (POINTER_TYPE_P (type) == POINTER_TYPE_P (itype) - || (TYPE_PRECISION (type) == TYPE_PRECISION (sizetype) - && TYPE_PRECISION (itype) == TYPE_PRECISION (sizetype)))) - { - if (POINTER_TYPE_P (type)) - { - split_constant_offset (op0, var, off, nullptr, cache, limit); - *var = fold_convert (type, *var); - } - else if (POINTER_TYPE_P (itype)) - { - split_constant_offset (op0, var, off, nullptr, cache, limit); - *var = fold_convert (sizetype, *var); - } - else - { - split_constant_offset (op0, var, off, &op0_range, - cache, limit); - if (!nop_conversion_for_offset_p (type, itype, op0_range)) - return false; - if (result_range) - { - *result_range = op0_range; - range_cast (*result_range, type); - } - } - return true; - } - return false; - } - - default: - return false; - } -} - -/* If EXP has pointer type, try to express it as: - - POINTER_PLUS <*VAR, (sizetype) *OFF> - - where: - - - *VAR has the same type as EXP - - *OFF is a constant of type ssizetype. - - If EXP has an integral type, try to express (sizetype) EXP as: - - *VAR + (sizetype) *OFF - - where: - - - *VAR has type sizetype - - *OFF is a constant of type ssizetype. - - If EXP_RANGE is nonnull, set it to the range of EXP. - - CACHE caches {*VAR, *OFF} pairs for SSA names that we've previously - visited. LIMIT counts down the number of SSA names that we are - allowed to process before giving up. */ - -static void -split_constant_offset (tree exp, tree *var, tree *off, value_range *exp_range, - hash_map<tree, std::pair<tree, tree> > &cache, - unsigned *limit) -{ - tree type = TREE_TYPE (exp), op0, op1; - enum tree_code code; - - code = TREE_CODE (exp); - if (exp_range) - { - *exp_range = type; - if (code == SSA_NAME) - { - value_range vr; - get_range_query (cfun)->range_of_expr (vr, exp); - if (vr.undefined_p ()) - vr.set_varying (TREE_TYPE (exp)); - wide_int var_min = wi::to_wide (vr.min ()); - wide_int var_max = wi::to_wide (vr.max ()); - value_range_kind vr_kind = vr.kind (); - wide_int var_nonzero = get_nonzero_bits (exp); - vr_kind = intersect_range_with_nonzero_bits (vr_kind, - &var_min, &var_max, - var_nonzero, - TYPE_SIGN (type)); - /* This check for VR_VARYING is here because the old code - using get_range_info would return VR_RANGE for the entire - domain, instead of VR_VARYING. The new code normalizes - full-domain ranges to VR_VARYING. */ - if (vr_kind == VR_RANGE || vr_kind == VR_VARYING) - *exp_range = value_range (type, var_min, var_max); - } - } - - if (!tree_is_chrec (exp) - && get_gimple_rhs_class (TREE_CODE (exp)) != GIMPLE_TERNARY_RHS) - { - extract_ops_from_tree (exp, &code, &op0, &op1); - if (split_constant_offset_1 (type, op0, code, op1, var, off, - exp_range, cache, limit)) - return; - } - - *var = exp; - if (INTEGRAL_TYPE_P (type)) - *var = fold_convert (sizetype, *var); - *off = ssize_int (0); - - value_range r; - if (exp_range && code != SSA_NAME - && get_range_query (cfun)->range_of_expr (r, exp) - && !r.undefined_p ()) - *exp_range = r; -} - -/* Expresses EXP as VAR + OFF, where OFF is a constant. VAR has the same - type as EXP while OFF has type ssizetype. */ - -void -split_constant_offset (tree exp, tree *var, tree *off) -{ - unsigned limit = param_ssa_name_def_chain_limit; - static hash_map<tree, std::pair<tree, tree> > *cache; - if (!cache) - cache = new hash_map<tree, std::pair<tree, tree> > (37); - split_constant_offset (exp, var, off, nullptr, *cache, &limit); - *var = fold_convert (TREE_TYPE (exp), *var); - cache->empty (); -} - -/* Returns the address ADDR of an object in a canonical shape (without nop - casts, and with type of pointer to the object). */ - -static tree -canonicalize_base_object_address (tree addr) -{ - tree orig = addr; - - STRIP_NOPS (addr); - - /* The base address may be obtained by casting from integer, in that case - keep the cast. */ - if (!POINTER_TYPE_P (TREE_TYPE (addr))) - return orig; - - if (TREE_CODE (addr) != ADDR_EXPR) - return addr; - - return build_fold_addr_expr (TREE_OPERAND (addr, 0)); -} - -/* Analyze the behavior of memory reference REF within STMT. - There are two modes: - - - BB analysis. In this case we simply split the address into base, - init and offset components, without reference to any containing loop. - The resulting base and offset are general expressions and they can - vary arbitrarily from one iteration of the containing loop to the next. - The step is always zero. - - - loop analysis. In this case we analyze the reference both wrt LOOP - and on the basis that the reference occurs (is "used") in LOOP; - see the comment above analyze_scalar_evolution_in_loop for more - information about this distinction. The base, init, offset and - step fields are all invariant in LOOP. - - Perform BB analysis if LOOP is null, or if LOOP is the function's - dummy outermost loop. In other cases perform loop analysis. - - Return true if the analysis succeeded and store the results in DRB if so. - BB analysis can only fail for bitfield or reversed-storage accesses. */ - -opt_result -dr_analyze_innermost (innermost_loop_behavior *drb, tree ref, - class loop *loop, const gimple *stmt) -{ - poly_int64 pbitsize, pbitpos; - tree base, poffset; - machine_mode pmode; - int punsignedp, preversep, pvolatilep; - affine_iv base_iv, offset_iv; - tree init, dinit, step; - bool in_loop = (loop && loop->num); - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "analyze_innermost: "); - - base = get_inner_reference (ref, &pbitsize, &pbitpos, &poffset, &pmode, - &punsignedp, &preversep, &pvolatilep); - gcc_assert (base != NULL_TREE); - - poly_int64 pbytepos; - if (!multiple_p (pbitpos, BITS_PER_UNIT, &pbytepos)) - return opt_result::failure_at (stmt, - "failed: bit offset alignment.\n"); - - if (preversep) - return opt_result::failure_at (stmt, - "failed: reverse storage order.\n"); - - /* Calculate the alignment and misalignment for the inner reference. */ - unsigned int HOST_WIDE_INT bit_base_misalignment; - unsigned int bit_base_alignment; - get_object_alignment_1 (base, &bit_base_alignment, &bit_base_misalignment); - - /* There are no bitfield references remaining in BASE, so the values - we got back must be whole bytes. */ - gcc_assert (bit_base_alignment % BITS_PER_UNIT == 0 - && bit_base_misalignment % BITS_PER_UNIT == 0); - unsigned int base_alignment = bit_base_alignment / BITS_PER_UNIT; - poly_int64 base_misalignment = bit_base_misalignment / BITS_PER_UNIT; - - if (TREE_CODE (base) == MEM_REF) - { - if (!integer_zerop (TREE_OPERAND (base, 1))) - { - /* Subtract MOFF from the base and add it to POFFSET instead. - Adjust the misalignment to reflect the amount we subtracted. */ - poly_offset_int moff = mem_ref_offset (base); - base_misalignment -= moff.force_shwi (); - tree mofft = wide_int_to_tree (sizetype, moff); - if (!poffset) - poffset = mofft; - else - poffset = size_binop (PLUS_EXPR, poffset, mofft); - } - base = TREE_OPERAND (base, 0); - } - else - base = build_fold_addr_expr (base); - - if (in_loop) - { - if (!simple_iv (loop, loop, base, &base_iv, true)) - return opt_result::failure_at - (stmt, "failed: evolution of base is not affine.\n"); - } - else - { - base_iv.base = base; - base_iv.step = ssize_int (0); - base_iv.no_overflow = true; - } - - if (!poffset) - { - offset_iv.base = ssize_int (0); - offset_iv.step = ssize_int (0); - } - else - { - if (!in_loop) - { - offset_iv.base = poffset; - offset_iv.step = ssize_int (0); - } - else if (!simple_iv (loop, loop, poffset, &offset_iv, true)) - return opt_result::failure_at - (stmt, "failed: evolution of offset is not affine.\n"); - } - - init = ssize_int (pbytepos); - - /* Subtract any constant component from the base and add it to INIT instead. - Adjust the misalignment to reflect the amount we subtracted. */ - split_constant_offset (base_iv.base, &base_iv.base, &dinit); - init = size_binop (PLUS_EXPR, init, dinit); - base_misalignment -= TREE_INT_CST_LOW (dinit); - - split_constant_offset (offset_iv.base, &offset_iv.base, &dinit); - init = size_binop (PLUS_EXPR, init, dinit); - - step = size_binop (PLUS_EXPR, - fold_convert (ssizetype, base_iv.step), - fold_convert (ssizetype, offset_iv.step)); - - base = canonicalize_base_object_address (base_iv.base); - - /* See if get_pointer_alignment can guarantee a higher alignment than - the one we calculated above. */ - unsigned int HOST_WIDE_INT alt_misalignment; - unsigned int alt_alignment; - get_pointer_alignment_1 (base, &alt_alignment, &alt_misalignment); - - /* As above, these values must be whole bytes. */ - gcc_assert (alt_alignment % BITS_PER_UNIT == 0 - && alt_misalignment % BITS_PER_UNIT == 0); - alt_alignment /= BITS_PER_UNIT; - alt_misalignment /= BITS_PER_UNIT; - - if (base_alignment < alt_alignment) - { - base_alignment = alt_alignment; - base_misalignment = alt_misalignment; - } - - drb->base_address = base; - drb->offset = fold_convert (ssizetype, offset_iv.base); - drb->init = init; - drb->step = step; - if (known_misalignment (base_misalignment, base_alignment, - &drb->base_misalignment)) - drb->base_alignment = base_alignment; - else - { - drb->base_alignment = known_alignment (base_misalignment); - drb->base_misalignment = 0; - } - drb->offset_alignment = highest_pow2_factor (offset_iv.base); - drb->step_alignment = highest_pow2_factor (step); - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "success.\n"); - - return opt_result::success (); -} - -/* Return true if OP is a valid component reference for a DR access - function. This accepts a subset of what handled_component_p accepts. */ - -static bool -access_fn_component_p (tree op) -{ - switch (TREE_CODE (op)) - { - case REALPART_EXPR: - case IMAGPART_EXPR: - case ARRAY_REF: - return true; - - case COMPONENT_REF: - return TREE_CODE (TREE_TYPE (TREE_OPERAND (op, 0))) == RECORD_TYPE; - - default: - return false; - } -} - -/* Returns whether BASE can have a access_fn_component_p with BASE - as base. */ - -static bool -base_supports_access_fn_components_p (tree base) -{ - switch (TREE_CODE (TREE_TYPE (base))) - { - case COMPLEX_TYPE: - case ARRAY_TYPE: - case RECORD_TYPE: - return true; - default: - return false; - } -} - -/* Determines the base object and the list of indices of memory reference - DR, analyzed in LOOP and instantiated before NEST. */ - -static void -dr_analyze_indices (struct indices *dri, tree ref, edge nest, loop_p loop) -{ - /* If analyzing a basic-block there are no indices to analyze - and thus no access functions. */ - if (!nest) - { - dri->base_object = ref; - dri->access_fns.create (0); - return; - } - - vec<tree> access_fns = vNULL; - - /* REALPART_EXPR and IMAGPART_EXPR can be handled like accesses - into a two element array with a constant index. The base is - then just the immediate underlying object. */ - if (TREE_CODE (ref) == REALPART_EXPR) - { - ref = TREE_OPERAND (ref, 0); - access_fns.safe_push (integer_zero_node); - } - else if (TREE_CODE (ref) == IMAGPART_EXPR) - { - ref = TREE_OPERAND (ref, 0); - access_fns.safe_push (integer_one_node); - } - - /* Analyze access functions of dimensions we know to be independent. - The list of component references handled here should be kept in - sync with access_fn_component_p. */ - while (handled_component_p (ref)) - { - if (TREE_CODE (ref) == ARRAY_REF) - { - tree op = TREE_OPERAND (ref, 1); - tree access_fn = analyze_scalar_evolution (loop, op); - access_fn = instantiate_scev (nest, loop, access_fn); - access_fns.safe_push (access_fn); - } - else if (TREE_CODE (ref) == COMPONENT_REF - && TREE_CODE (TREE_TYPE (TREE_OPERAND (ref, 0))) == RECORD_TYPE) - { - /* For COMPONENT_REFs of records (but not unions!) use the - FIELD_DECL offset as constant access function so we can - disambiguate a[i].f1 and a[i].f2. */ - tree off = component_ref_field_offset (ref); - off = size_binop (PLUS_EXPR, - size_binop (MULT_EXPR, - fold_convert (bitsizetype, off), - bitsize_int (BITS_PER_UNIT)), - DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1))); - access_fns.safe_push (off); - } - else - /* If we have an unhandled component we could not translate - to an access function stop analyzing. We have determined - our base object in this case. */ - break; - - ref = TREE_OPERAND (ref, 0); - } - - /* If the address operand of a MEM_REF base has an evolution in the - analyzed nest, add it as an additional independent access-function. */ - if (TREE_CODE (ref) == MEM_REF) - { - tree op = TREE_OPERAND (ref, 0); - tree access_fn = analyze_scalar_evolution (loop, op); - access_fn = instantiate_scev (nest, loop, access_fn); - STRIP_NOPS (access_fn); - if (TREE_CODE (access_fn) == POLYNOMIAL_CHREC) - { - tree memoff = TREE_OPERAND (ref, 1); - tree base = initial_condition (access_fn); - tree orig_type = TREE_TYPE (base); - STRIP_USELESS_TYPE_CONVERSION (base); - tree off; - split_constant_offset (base, &base, &off); - STRIP_USELESS_TYPE_CONVERSION (base); - /* Fold the MEM_REF offset into the evolutions initial - value to make more bases comparable. */ - if (!integer_zerop (memoff)) - { - off = size_binop (PLUS_EXPR, off, - fold_convert (ssizetype, memoff)); - memoff = build_int_cst (TREE_TYPE (memoff), 0); - } - /* Adjust the offset so it is a multiple of the access type - size and thus we separate bases that can possibly be used - to produce partial overlaps (which the access_fn machinery - cannot handle). */ - wide_int rem; - if (TYPE_SIZE_UNIT (TREE_TYPE (ref)) - && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (ref))) == INTEGER_CST - && !integer_zerop (TYPE_SIZE_UNIT (TREE_TYPE (ref)))) - rem = wi::mod_trunc - (wi::to_wide (off), - wi::to_wide (TYPE_SIZE_UNIT (TREE_TYPE (ref))), - SIGNED); - else - /* If we can't compute the remainder simply force the initial - condition to zero. */ - rem = wi::to_wide (off); - off = wide_int_to_tree (ssizetype, wi::to_wide (off) - rem); - memoff = wide_int_to_tree (TREE_TYPE (memoff), rem); - /* And finally replace the initial condition. */ - access_fn = chrec_replace_initial_condition - (access_fn, fold_convert (orig_type, off)); - /* ??? This is still not a suitable base object for - dr_may_alias_p - the base object needs to be an - access that covers the object as whole. With - an evolution in the pointer this cannot be - guaranteed. - As a band-aid, mark the access so we can special-case - it in dr_may_alias_p. */ - tree old = ref; - ref = fold_build2_loc (EXPR_LOCATION (ref), - MEM_REF, TREE_TYPE (ref), - base, memoff); - MR_DEPENDENCE_CLIQUE (ref) = MR_DEPENDENCE_CLIQUE (old); - MR_DEPENDENCE_BASE (ref) = MR_DEPENDENCE_BASE (old); - dri->unconstrained_base = true; - access_fns.safe_push (access_fn); - } - } - else if (DECL_P (ref)) - { - /* Canonicalize DR_BASE_OBJECT to MEM_REF form. */ - ref = build2 (MEM_REF, TREE_TYPE (ref), - build_fold_addr_expr (ref), - build_int_cst (reference_alias_ptr_type (ref), 0)); - } - - dri->base_object = ref; - dri->access_fns = access_fns; -} - -/* Extracts the alias analysis information from the memory reference DR. */ - -static void -dr_analyze_alias (struct data_reference *dr) -{ - tree ref = DR_REF (dr); - tree base = get_base_address (ref), addr; - - if (INDIRECT_REF_P (base) - || TREE_CODE (base) == MEM_REF) - { - addr = TREE_OPERAND (base, 0); - if (TREE_CODE (addr) == SSA_NAME) - DR_PTR_INFO (dr) = SSA_NAME_PTR_INFO (addr); - } -} - -/* Frees data reference DR. */ - -void -free_data_ref (data_reference_p dr) -{ - DR_ACCESS_FNS (dr).release (); - if (dr->alt_indices.base_object) - dr->alt_indices.access_fns.release (); - free (dr); -} - -/* Analyze memory reference MEMREF, which is accessed in STMT. - The reference is a read if IS_READ is true, otherwise it is a write. - IS_CONDITIONAL_IN_STMT indicates that the reference is conditional - within STMT, i.e. that it might not occur even if STMT is executed - and runs to completion. - - Return the data_reference description of MEMREF. NEST is the outermost - loop in which the reference should be instantiated, LOOP is the loop - in which the data reference should be analyzed. */ - -struct data_reference * -create_data_ref (edge nest, loop_p loop, tree memref, gimple *stmt, - bool is_read, bool is_conditional_in_stmt) -{ - struct data_reference *dr; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Creating dr for "); - print_generic_expr (dump_file, memref, TDF_SLIM); - fprintf (dump_file, "\n"); - } - - dr = XCNEW (struct data_reference); - DR_STMT (dr) = stmt; - DR_REF (dr) = memref; - DR_IS_READ (dr) = is_read; - DR_IS_CONDITIONAL_IN_STMT (dr) = is_conditional_in_stmt; - - dr_analyze_innermost (&DR_INNERMOST (dr), memref, - nest != NULL ? loop : NULL, stmt); - dr_analyze_indices (&dr->indices, DR_REF (dr), nest, loop); - dr_analyze_alias (dr); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - unsigned i; - fprintf (dump_file, "\tbase_address: "); - print_generic_expr (dump_file, DR_BASE_ADDRESS (dr), TDF_SLIM); - fprintf (dump_file, "\n\toffset from base address: "); - print_generic_expr (dump_file, DR_OFFSET (dr), TDF_SLIM); - fprintf (dump_file, "\n\tconstant offset from base address: "); - print_generic_expr (dump_file, DR_INIT (dr), TDF_SLIM); - fprintf (dump_file, "\n\tstep: "); - print_generic_expr (dump_file, DR_STEP (dr), TDF_SLIM); - fprintf (dump_file, "\n\tbase alignment: %d", DR_BASE_ALIGNMENT (dr)); - fprintf (dump_file, "\n\tbase misalignment: %d", - DR_BASE_MISALIGNMENT (dr)); - fprintf (dump_file, "\n\toffset alignment: %d", - DR_OFFSET_ALIGNMENT (dr)); - fprintf (dump_file, "\n\tstep alignment: %d", DR_STEP_ALIGNMENT (dr)); - fprintf (dump_file, "\n\tbase_object: "); - print_generic_expr (dump_file, DR_BASE_OBJECT (dr), TDF_SLIM); - fprintf (dump_file, "\n"); - for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++) - { - fprintf (dump_file, "\tAccess function %d: ", i); - print_generic_stmt (dump_file, DR_ACCESS_FN (dr, i), TDF_SLIM); - } - } - - return dr; -} - -/* A helper function computes order between two tree expressions T1 and T2. - This is used in comparator functions sorting objects based on the order - of tree expressions. The function returns -1, 0, or 1. */ - -int -data_ref_compare_tree (tree t1, tree t2) -{ - int i, cmp; - enum tree_code code; - char tclass; - - if (t1 == t2) - return 0; - if (t1 == NULL) - return -1; - if (t2 == NULL) - return 1; - - STRIP_USELESS_TYPE_CONVERSION (t1); - STRIP_USELESS_TYPE_CONVERSION (t2); - if (t1 == t2) - return 0; - - if (TREE_CODE (t1) != TREE_CODE (t2) - && ! (CONVERT_EXPR_P (t1) && CONVERT_EXPR_P (t2))) - return TREE_CODE (t1) < TREE_CODE (t2) ? -1 : 1; - - code = TREE_CODE (t1); - switch (code) - { - case INTEGER_CST: - return tree_int_cst_compare (t1, t2); - - case STRING_CST: - if (TREE_STRING_LENGTH (t1) != TREE_STRING_LENGTH (t2)) - return TREE_STRING_LENGTH (t1) < TREE_STRING_LENGTH (t2) ? -1 : 1; - return memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2), - TREE_STRING_LENGTH (t1)); - - case SSA_NAME: - if (SSA_NAME_VERSION (t1) != SSA_NAME_VERSION (t2)) - return SSA_NAME_VERSION (t1) < SSA_NAME_VERSION (t2) ? -1 : 1; - break; - - default: - if (POLY_INT_CST_P (t1)) - return compare_sizes_for_sort (wi::to_poly_widest (t1), - wi::to_poly_widest (t2)); - - tclass = TREE_CODE_CLASS (code); - - /* For decls, compare their UIDs. */ - if (tclass == tcc_declaration) - { - if (DECL_UID (t1) != DECL_UID (t2)) - return DECL_UID (t1) < DECL_UID (t2) ? -1 : 1; - break; - } - /* For expressions, compare their operands recursively. */ - else if (IS_EXPR_CODE_CLASS (tclass)) - { - for (i = TREE_OPERAND_LENGTH (t1) - 1; i >= 0; --i) - { - cmp = data_ref_compare_tree (TREE_OPERAND (t1, i), - TREE_OPERAND (t2, i)); - if (cmp != 0) - return cmp; - } - } - else - gcc_unreachable (); - } - - return 0; -} - -/* Return TRUE it's possible to resolve data dependence DDR by runtime alias - check. */ - -opt_result -runtime_alias_check_p (ddr_p ddr, class loop *loop, bool speed_p) -{ - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, - "consider run-time aliasing test between %T and %T\n", - DR_REF (DDR_A (ddr)), DR_REF (DDR_B (ddr))); - - if (!speed_p) - return opt_result::failure_at (DR_STMT (DDR_A (ddr)), - "runtime alias check not supported when" - " optimizing for size.\n"); - - /* FORNOW: We don't support versioning with outer-loop in either - vectorization or loop distribution. */ - if (loop != NULL && loop->inner != NULL) - return opt_result::failure_at (DR_STMT (DDR_A (ddr)), - "runtime alias check not supported for" - " outer loop.\n"); - - return opt_result::success (); -} - -/* Operator == between two dr_with_seg_len objects. - - This equality operator is used to make sure two data refs - are the same one so that we will consider to combine the - aliasing checks of those two pairs of data dependent data - refs. */ - -static bool -operator == (const dr_with_seg_len& d1, - const dr_with_seg_len& d2) -{ - return (operand_equal_p (DR_BASE_ADDRESS (d1.dr), - DR_BASE_ADDRESS (d2.dr), 0) - && data_ref_compare_tree (DR_OFFSET (d1.dr), DR_OFFSET (d2.dr)) == 0 - && data_ref_compare_tree (DR_INIT (d1.dr), DR_INIT (d2.dr)) == 0 - && data_ref_compare_tree (d1.seg_len, d2.seg_len) == 0 - && known_eq (d1.access_size, d2.access_size) - && d1.align == d2.align); -} - -/* Comparison function for sorting objects of dr_with_seg_len_pair_t - so that we can combine aliasing checks in one scan. */ - -static int -comp_dr_with_seg_len_pair (const void *pa_, const void *pb_) -{ - const dr_with_seg_len_pair_t* pa = (const dr_with_seg_len_pair_t *) pa_; - const dr_with_seg_len_pair_t* pb = (const dr_with_seg_len_pair_t *) pb_; - const dr_with_seg_len &a1 = pa->first, &a2 = pa->second; - const dr_with_seg_len &b1 = pb->first, &b2 = pb->second; - - /* For DR pairs (a, b) and (c, d), we only consider to merge the alias checks - if a and c have the same basic address snd step, and b and d have the same - address and step. Therefore, if any a&c or b&d don't have the same address - and step, we don't care the order of those two pairs after sorting. */ - int comp_res; - - if ((comp_res = data_ref_compare_tree (DR_BASE_ADDRESS (a1.dr), - DR_BASE_ADDRESS (b1.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_BASE_ADDRESS (a2.dr), - DR_BASE_ADDRESS (b2.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_STEP (a1.dr), - DR_STEP (b1.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_STEP (a2.dr), - DR_STEP (b2.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_OFFSET (a1.dr), - DR_OFFSET (b1.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_INIT (a1.dr), - DR_INIT (b1.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_OFFSET (a2.dr), - DR_OFFSET (b2.dr))) != 0) - return comp_res; - if ((comp_res = data_ref_compare_tree (DR_INIT (a2.dr), - DR_INIT (b2.dr))) != 0) - return comp_res; - - return 0; -} - -/* Dump information about ALIAS_PAIR, indenting each line by INDENT. */ - -static void -dump_alias_pair (dr_with_seg_len_pair_t *alias_pair, const char *indent) -{ - dump_printf (MSG_NOTE, "%sreference: %T vs. %T\n", indent, - DR_REF (alias_pair->first.dr), - DR_REF (alias_pair->second.dr)); - - dump_printf (MSG_NOTE, "%ssegment length: %T", indent, - alias_pair->first.seg_len); - if (!operand_equal_p (alias_pair->first.seg_len, - alias_pair->second.seg_len, 0)) - dump_printf (MSG_NOTE, " vs. %T", alias_pair->second.seg_len); - - dump_printf (MSG_NOTE, "\n%saccess size: ", indent); - dump_dec (MSG_NOTE, alias_pair->first.access_size); - if (maybe_ne (alias_pair->first.access_size, alias_pair->second.access_size)) - { - dump_printf (MSG_NOTE, " vs. "); - dump_dec (MSG_NOTE, alias_pair->second.access_size); - } - - dump_printf (MSG_NOTE, "\n%salignment: %d", indent, - alias_pair->first.align); - if (alias_pair->first.align != alias_pair->second.align) - dump_printf (MSG_NOTE, " vs. %d", alias_pair->second.align); - - dump_printf (MSG_NOTE, "\n%sflags: ", indent); - if (alias_pair->flags & DR_ALIAS_RAW) - dump_printf (MSG_NOTE, " RAW"); - if (alias_pair->flags & DR_ALIAS_WAR) - dump_printf (MSG_NOTE, " WAR"); - if (alias_pair->flags & DR_ALIAS_WAW) - dump_printf (MSG_NOTE, " WAW"); - if (alias_pair->flags & DR_ALIAS_ARBITRARY) - dump_printf (MSG_NOTE, " ARBITRARY"); - if (alias_pair->flags & DR_ALIAS_SWAPPED) - dump_printf (MSG_NOTE, " SWAPPED"); - if (alias_pair->flags & DR_ALIAS_UNSWAPPED) - dump_printf (MSG_NOTE, " UNSWAPPED"); - if (alias_pair->flags & DR_ALIAS_MIXED_STEPS) - dump_printf (MSG_NOTE, " MIXED_STEPS"); - if (alias_pair->flags == 0) - dump_printf (MSG_NOTE, " <none>"); - dump_printf (MSG_NOTE, "\n"); -} - -/* Merge alias checks recorded in ALIAS_PAIRS and remove redundant ones. - FACTOR is number of iterations that each data reference is accessed. - - Basically, for each pair of dependent data refs store_ptr_0 & load_ptr_0, - we create an expression: - - ((store_ptr_0 + store_segment_length_0) <= load_ptr_0) - || (load_ptr_0 + load_segment_length_0) <= store_ptr_0)) - - for aliasing checks. However, in some cases we can decrease the number - of checks by combining two checks into one. For example, suppose we have - another pair of data refs store_ptr_0 & load_ptr_1, and if the following - condition is satisfied: - - load_ptr_0 < load_ptr_1 && - load_ptr_1 - load_ptr_0 - load_segment_length_0 < store_segment_length_0 - - (this condition means, in each iteration of vectorized loop, the accessed - memory of store_ptr_0 cannot be between the memory of load_ptr_0 and - load_ptr_1.) - - we then can use only the following expression to finish the alising checks - between store_ptr_0 & load_ptr_0 and store_ptr_0 & load_ptr_1: - - ((store_ptr_0 + store_segment_length_0) <= load_ptr_0) - || (load_ptr_1 + load_segment_length_1 <= store_ptr_0)) - - Note that we only consider that load_ptr_0 and load_ptr_1 have the same - basic address. */ - -void -prune_runtime_alias_test_list (vec<dr_with_seg_len_pair_t> *alias_pairs, - poly_uint64) -{ - if (alias_pairs->is_empty ()) - return; - - /* Canonicalize each pair so that the base components are ordered wrt - data_ref_compare_tree. This allows the loop below to merge more - cases. */ - unsigned int i; - dr_with_seg_len_pair_t *alias_pair; - FOR_EACH_VEC_ELT (*alias_pairs, i, alias_pair) - { - data_reference_p dr_a = alias_pair->first.dr; - data_reference_p dr_b = alias_pair->second.dr; - int comp_res = data_ref_compare_tree (DR_BASE_ADDRESS (dr_a), - DR_BASE_ADDRESS (dr_b)); - if (comp_res == 0) - comp_res = data_ref_compare_tree (DR_OFFSET (dr_a), DR_OFFSET (dr_b)); - if (comp_res == 0) - comp_res = data_ref_compare_tree (DR_INIT (dr_a), DR_INIT (dr_b)); - if (comp_res > 0) - { - std::swap (alias_pair->first, alias_pair->second); - alias_pair->flags |= DR_ALIAS_SWAPPED; - } - else - alias_pair->flags |= DR_ALIAS_UNSWAPPED; - } - - /* Sort the collected data ref pairs so that we can scan them once to - combine all possible aliasing checks. */ - alias_pairs->qsort (comp_dr_with_seg_len_pair); - - /* Scan the sorted dr pairs and check if we can combine alias checks - of two neighboring dr pairs. */ - unsigned int last = 0; - for (i = 1; i < alias_pairs->length (); ++i) - { - /* Deal with two ddrs (dr_a1, dr_b1) and (dr_a2, dr_b2). */ - dr_with_seg_len_pair_t *alias_pair1 = &(*alias_pairs)[last]; - dr_with_seg_len_pair_t *alias_pair2 = &(*alias_pairs)[i]; - - dr_with_seg_len *dr_a1 = &alias_pair1->first; - dr_with_seg_len *dr_b1 = &alias_pair1->second; - dr_with_seg_len *dr_a2 = &alias_pair2->first; - dr_with_seg_len *dr_b2 = &alias_pair2->second; - - /* Remove duplicate data ref pairs. */ - if (*dr_a1 == *dr_a2 && *dr_b1 == *dr_b2) - { - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, "found equal ranges %T, %T and %T, %T\n", - DR_REF (dr_a1->dr), DR_REF (dr_b1->dr), - DR_REF (dr_a2->dr), DR_REF (dr_b2->dr)); - alias_pair1->flags |= alias_pair2->flags; - continue; - } - - /* Assume that we won't be able to merge the pairs, then correct - if we do. */ - last += 1; - if (last != i) - (*alias_pairs)[last] = (*alias_pairs)[i]; - - if (*dr_a1 == *dr_a2 || *dr_b1 == *dr_b2) - { - /* We consider the case that DR_B1 and DR_B2 are same memrefs, - and DR_A1 and DR_A2 are two consecutive memrefs. */ - if (*dr_a1 == *dr_a2) - { - std::swap (dr_a1, dr_b1); - std::swap (dr_a2, dr_b2); - } - - poly_int64 init_a1, init_a2; - /* Only consider cases in which the distance between the initial - DR_A1 and the initial DR_A2 is known at compile time. */ - if (!operand_equal_p (DR_BASE_ADDRESS (dr_a1->dr), - DR_BASE_ADDRESS (dr_a2->dr), 0) - || !operand_equal_p (DR_OFFSET (dr_a1->dr), - DR_OFFSET (dr_a2->dr), 0) - || !poly_int_tree_p (DR_INIT (dr_a1->dr), &init_a1) - || !poly_int_tree_p (DR_INIT (dr_a2->dr), &init_a2)) - continue; - - /* Don't combine if we can't tell which one comes first. */ - if (!ordered_p (init_a1, init_a2)) - continue; - - /* Work out what the segment length would be if we did combine - DR_A1 and DR_A2: - - - If DR_A1 and DR_A2 have equal lengths, that length is - also the combined length. - - - If DR_A1 and DR_A2 both have negative "lengths", the combined - length is the lower bound on those lengths. - - - If DR_A1 and DR_A2 both have positive lengths, the combined - length is the upper bound on those lengths. - - Other cases are unlikely to give a useful combination. - - The lengths both have sizetype, so the sign is taken from - the step instead. */ - poly_uint64 new_seg_len = 0; - bool new_seg_len_p = !operand_equal_p (dr_a1->seg_len, - dr_a2->seg_len, 0); - if (new_seg_len_p) - { - poly_uint64 seg_len_a1, seg_len_a2; - if (!poly_int_tree_p (dr_a1->seg_len, &seg_len_a1) - || !poly_int_tree_p (dr_a2->seg_len, &seg_len_a2)) - continue; - - tree indicator_a = dr_direction_indicator (dr_a1->dr); - if (TREE_CODE (indicator_a) != INTEGER_CST) - continue; - - tree indicator_b = dr_direction_indicator (dr_a2->dr); - if (TREE_CODE (indicator_b) != INTEGER_CST) - continue; - - int sign_a = tree_int_cst_sgn (indicator_a); - int sign_b = tree_int_cst_sgn (indicator_b); - - if (sign_a <= 0 && sign_b <= 0) - new_seg_len = lower_bound (seg_len_a1, seg_len_a2); - else if (sign_a >= 0 && sign_b >= 0) - new_seg_len = upper_bound (seg_len_a1, seg_len_a2); - else - continue; - } - /* At this point we're committed to merging the refs. */ - - /* Make sure dr_a1 starts left of dr_a2. */ - if (maybe_gt (init_a1, init_a2)) - { - std::swap (*dr_a1, *dr_a2); - std::swap (init_a1, init_a2); - } - - /* The DR_Bs are equal, so only the DR_As can introduce - mixed steps. */ - if (!operand_equal_p (DR_STEP (dr_a1->dr), DR_STEP (dr_a2->dr), 0)) - alias_pair1->flags |= DR_ALIAS_MIXED_STEPS; - - if (new_seg_len_p) - { - dr_a1->seg_len = build_int_cst (TREE_TYPE (dr_a1->seg_len), - new_seg_len); - dr_a1->align = MIN (dr_a1->align, known_alignment (new_seg_len)); - } - - /* This is always positive due to the swap above. */ - poly_uint64 diff = init_a2 - init_a1; - - /* The new check will start at DR_A1. Make sure that its access - size encompasses the initial DR_A2. */ - if (maybe_lt (dr_a1->access_size, diff + dr_a2->access_size)) - { - dr_a1->access_size = upper_bound (dr_a1->access_size, - diff + dr_a2->access_size); - unsigned int new_align = known_alignment (dr_a1->access_size); - dr_a1->align = MIN (dr_a1->align, new_align); - } - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, "merging ranges for %T, %T and %T, %T\n", - DR_REF (dr_a1->dr), DR_REF (dr_b1->dr), - DR_REF (dr_a2->dr), DR_REF (dr_b2->dr)); - alias_pair1->flags |= alias_pair2->flags; - last -= 1; - } - } - alias_pairs->truncate (last + 1); - - /* Try to restore the original dr_with_seg_len order within each - dr_with_seg_len_pair_t. If we ended up combining swapped and - unswapped pairs into the same check, we have to invalidate any - RAW, WAR and WAW information for it. */ - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, "merged alias checks:\n"); - FOR_EACH_VEC_ELT (*alias_pairs, i, alias_pair) - { - unsigned int swap_mask = (DR_ALIAS_SWAPPED | DR_ALIAS_UNSWAPPED); - unsigned int swapped = (alias_pair->flags & swap_mask); - if (swapped == DR_ALIAS_SWAPPED) - std::swap (alias_pair->first, alias_pair->second); - else if (swapped != DR_ALIAS_UNSWAPPED) - alias_pair->flags |= DR_ALIAS_ARBITRARY; - alias_pair->flags &= ~swap_mask; - if (dump_enabled_p ()) - dump_alias_pair (alias_pair, " "); - } -} - -/* A subroutine of create_intersect_range_checks, with a subset of the - same arguments. Try to use IFN_CHECK_RAW_PTRS and IFN_CHECK_WAR_PTRS - to optimize cases in which the references form a simple RAW, WAR or - WAR dependence. */ - -static bool -create_ifn_alias_checks (tree *cond_expr, - const dr_with_seg_len_pair_t &alias_pair) -{ - const dr_with_seg_len& dr_a = alias_pair.first; - const dr_with_seg_len& dr_b = alias_pair.second; - - /* Check for cases in which: - - (a) we have a known RAW, WAR or WAR dependence - (b) the accesses are well-ordered in both the original and new code - (see the comment above the DR_ALIAS_* flags for details); and - (c) the DR_STEPs describe all access pairs covered by ALIAS_PAIR. */ - if (alias_pair.flags & ~(DR_ALIAS_RAW | DR_ALIAS_WAR | DR_ALIAS_WAW)) - return false; - - /* Make sure that both DRs access the same pattern of bytes, - with a constant length and step. */ - poly_uint64 seg_len; - if (!operand_equal_p (dr_a.seg_len, dr_b.seg_len, 0) - || !poly_int_tree_p (dr_a.seg_len, &seg_len) - || maybe_ne (dr_a.access_size, dr_b.access_size) - || !operand_equal_p (DR_STEP (dr_a.dr), DR_STEP (dr_b.dr), 0) - || !tree_fits_uhwi_p (DR_STEP (dr_a.dr))) - return false; - - unsigned HOST_WIDE_INT bytes = tree_to_uhwi (DR_STEP (dr_a.dr)); - tree addr_a = DR_BASE_ADDRESS (dr_a.dr); - tree addr_b = DR_BASE_ADDRESS (dr_b.dr); - - /* See whether the target suports what we want to do. WAW checks are - equivalent to WAR checks here. */ - internal_fn ifn = (alias_pair.flags & DR_ALIAS_RAW - ? IFN_CHECK_RAW_PTRS - : IFN_CHECK_WAR_PTRS); - unsigned int align = MIN (dr_a.align, dr_b.align); - poly_uint64 full_length = seg_len + bytes; - if (!internal_check_ptrs_fn_supported_p (ifn, TREE_TYPE (addr_a), - full_length, align)) - { - full_length = seg_len + dr_a.access_size; - if (!internal_check_ptrs_fn_supported_p (ifn, TREE_TYPE (addr_a), - full_length, align)) - return false; - } - - /* Commit to using this form of test. */ - addr_a = fold_build_pointer_plus (addr_a, DR_OFFSET (dr_a.dr)); - addr_a = fold_build_pointer_plus (addr_a, DR_INIT (dr_a.dr)); - - addr_b = fold_build_pointer_plus (addr_b, DR_OFFSET (dr_b.dr)); - addr_b = fold_build_pointer_plus (addr_b, DR_INIT (dr_b.dr)); - - *cond_expr = build_call_expr_internal_loc (UNKNOWN_LOCATION, - ifn, boolean_type_node, - 4, addr_a, addr_b, - size_int (full_length), - size_int (align)); - - if (dump_enabled_p ()) - { - if (ifn == IFN_CHECK_RAW_PTRS) - dump_printf (MSG_NOTE, "using an IFN_CHECK_RAW_PTRS test\n"); - else - dump_printf (MSG_NOTE, "using an IFN_CHECK_WAR_PTRS test\n"); - } - return true; -} - -/* Try to generate a runtime condition that is true if ALIAS_PAIR is - free of aliases, using a condition based on index values instead - of a condition based on addresses. Return true on success, - storing the condition in *COND_EXPR. - - This can only be done if the two data references in ALIAS_PAIR access - the same array object and the index is the only difference. For example, - if the two data references are DR_A and DR_B: - - DR_A DR_B - data-ref arr[i] arr[j] - base_object arr arr - index {i_0, +, 1}_loop {j_0, +, 1}_loop - - The addresses and their index are like: - - |<- ADDR_A ->| |<- ADDR_B ->| - -------------------------------------------------------> - | | | | | | | | | | - -------------------------------------------------------> - i_0 ... i_0+4 j_0 ... j_0+4 - - We can create expression based on index rather than address: - - (unsigned) (i_0 - j_0 + 3) <= 6 - - i.e. the indices are less than 4 apart. - - Note evolution step of index needs to be considered in comparison. */ - -static bool -create_intersect_range_checks_index (class loop *loop, tree *cond_expr, - const dr_with_seg_len_pair_t &alias_pair) -{ - const dr_with_seg_len &dr_a = alias_pair.first; - const dr_with_seg_len &dr_b = alias_pair.second; - if ((alias_pair.flags & DR_ALIAS_MIXED_STEPS) - || integer_zerop (DR_STEP (dr_a.dr)) - || integer_zerop (DR_STEP (dr_b.dr)) - || DR_NUM_DIMENSIONS (dr_a.dr) != DR_NUM_DIMENSIONS (dr_b.dr)) - return false; - - poly_uint64 seg_len1, seg_len2; - if (!poly_int_tree_p (dr_a.seg_len, &seg_len1) - || !poly_int_tree_p (dr_b.seg_len, &seg_len2)) - return false; - - if (!tree_fits_shwi_p (DR_STEP (dr_a.dr))) - return false; - - if (!operand_equal_p (DR_BASE_OBJECT (dr_a.dr), DR_BASE_OBJECT (dr_b.dr), 0)) - return false; - - if (!operand_equal_p (DR_STEP (dr_a.dr), DR_STEP (dr_b.dr), 0)) - return false; - - gcc_assert (TREE_CODE (DR_STEP (dr_a.dr)) == INTEGER_CST); - - bool neg_step = tree_int_cst_compare (DR_STEP (dr_a.dr), size_zero_node) < 0; - unsigned HOST_WIDE_INT abs_step = tree_to_shwi (DR_STEP (dr_a.dr)); - if (neg_step) - { - abs_step = -abs_step; - seg_len1 = (-wi::to_poly_wide (dr_a.seg_len)).force_uhwi (); - seg_len2 = (-wi::to_poly_wide (dr_b.seg_len)).force_uhwi (); - } - - /* Infer the number of iterations with which the memory segment is accessed - by DR. In other words, alias is checked if memory segment accessed by - DR_A in some iterations intersect with memory segment accessed by DR_B - in the same amount iterations. - Note segnment length is a linear function of number of iterations with - DR_STEP as the coefficient. */ - poly_uint64 niter_len1, niter_len2; - if (!can_div_trunc_p (seg_len1 + abs_step - 1, abs_step, &niter_len1) - || !can_div_trunc_p (seg_len2 + abs_step - 1, abs_step, &niter_len2)) - return false; - - /* Divide each access size by the byte step, rounding up. */ - poly_uint64 niter_access1, niter_access2; - if (!can_div_trunc_p (dr_a.access_size + abs_step - 1, - abs_step, &niter_access1) - || !can_div_trunc_p (dr_b.access_size + abs_step - 1, - abs_step, &niter_access2)) - return false; - - bool waw_or_war_p = (alias_pair.flags & ~(DR_ALIAS_WAR | DR_ALIAS_WAW)) == 0; - - int found = -1; - for (unsigned int i = 0; i < DR_NUM_DIMENSIONS (dr_a.dr); i++) - { - tree access1 = DR_ACCESS_FN (dr_a.dr, i); - tree access2 = DR_ACCESS_FN (dr_b.dr, i); - /* Two indices must be the same if they are not scev, or not scev wrto - current loop being vecorized. */ - if (TREE_CODE (access1) != POLYNOMIAL_CHREC - || TREE_CODE (access2) != POLYNOMIAL_CHREC - || CHREC_VARIABLE (access1) != (unsigned)loop->num - || CHREC_VARIABLE (access2) != (unsigned)loop->num) - { - if (operand_equal_p (access1, access2, 0)) - continue; - - return false; - } - if (found >= 0) - return false; - found = i; - } - - /* Ought not to happen in practice, since if all accesses are equal then the - alias should be decidable at compile time. */ - if (found < 0) - return false; - - /* The two indices must have the same step. */ - tree access1 = DR_ACCESS_FN (dr_a.dr, found); - tree access2 = DR_ACCESS_FN (dr_b.dr, found); - if (!operand_equal_p (CHREC_RIGHT (access1), CHREC_RIGHT (access2), 0)) - return false; - - tree idx_step = CHREC_RIGHT (access1); - /* Index must have const step, otherwise DR_STEP won't be constant. */ - gcc_assert (TREE_CODE (idx_step) == INTEGER_CST); - /* Index must evaluate in the same direction as DR. */ - gcc_assert (!neg_step || tree_int_cst_sign_bit (idx_step) == 1); - - tree min1 = CHREC_LEFT (access1); - tree min2 = CHREC_LEFT (access2); - if (!types_compatible_p (TREE_TYPE (min1), TREE_TYPE (min2))) - return false; - - /* Ideally, alias can be checked against loop's control IV, but we - need to prove linear mapping between control IV and reference - index. Although that should be true, we check against (array) - index of data reference. Like segment length, index length is - linear function of the number of iterations with index_step as - the coefficient, i.e, niter_len * idx_step. */ - offset_int abs_idx_step = offset_int::from (wi::to_wide (idx_step), - SIGNED); - if (neg_step) - abs_idx_step = -abs_idx_step; - poly_offset_int idx_len1 = abs_idx_step * niter_len1; - poly_offset_int idx_len2 = abs_idx_step * niter_len2; - poly_offset_int idx_access1 = abs_idx_step * niter_access1; - poly_offset_int idx_access2 = abs_idx_step * niter_access2; - - gcc_assert (known_ge (idx_len1, 0) - && known_ge (idx_len2, 0) - && known_ge (idx_access1, 0) - && known_ge (idx_access2, 0)); - - /* Each access has the following pattern, with lengths measured - in units of INDEX: - - <-- idx_len --> - <--- A: -ve step ---> - +-----+-------+-----+-------+-----+ - | n-1 | ..... | 0 | ..... | n-1 | - +-----+-------+-----+-------+-----+ - <--- B: +ve step ---> - <-- idx_len --> - | - min - - where "n" is the number of scalar iterations covered by the segment - and where each access spans idx_access units. - - A is the range of bytes accessed when the step is negative, - B is the range when the step is positive. - - When checking for general overlap, we need to test whether - the range: - - [min1 + low_offset1, min1 + high_offset1 + idx_access1 - 1] - - overlaps: - - [min2 + low_offset2, min2 + high_offset2 + idx_access2 - 1] - - where: - - low_offsetN = +ve step ? 0 : -idx_lenN; - high_offsetN = +ve step ? idx_lenN : 0; - - This is equivalent to testing whether: - - min1 + low_offset1 <= min2 + high_offset2 + idx_access2 - 1 - && min2 + low_offset2 <= min1 + high_offset1 + idx_access1 - 1 - - Converting this into a single test, there is an overlap if: - - 0 <= min2 - min1 + bias <= limit - - where bias = high_offset2 + idx_access2 - 1 - low_offset1 - limit = (high_offset1 - low_offset1 + idx_access1 - 1) - + (high_offset2 - low_offset2 + idx_access2 - 1) - i.e. limit = idx_len1 + idx_access1 - 1 + idx_len2 + idx_access2 - 1 - - Combining the tests requires limit to be computable in an unsigned - form of the index type; if it isn't, we fall back to the usual - pointer-based checks. - - We can do better if DR_B is a write and if DR_A and DR_B are - well-ordered in both the original and the new code (see the - comment above the DR_ALIAS_* flags for details). In this case - we know that for each i in [0, n-1], the write performed by - access i of DR_B occurs after access numbers j<=i of DR_A in - both the original and the new code. Any write or anti - dependencies wrt those DR_A accesses are therefore maintained. - - We just need to make sure that each individual write in DR_B does not - overlap any higher-indexed access in DR_A; such DR_A accesses happen - after the DR_B access in the original code but happen before it in - the new code. - - We know the steps for both accesses are equal, so by induction, we - just need to test whether the first write of DR_B overlaps a later - access of DR_A. In other words, we need to move min1 along by - one iteration: - - min1' = min1 + idx_step - - and use the ranges: - - [min1' + low_offset1', min1' + high_offset1' + idx_access1 - 1] - - and: - - [min2, min2 + idx_access2 - 1] - - where: - - low_offset1' = +ve step ? 0 : -(idx_len1 - |idx_step|) - high_offset1' = +ve_step ? idx_len1 - |idx_step| : 0. */ - if (waw_or_war_p) - idx_len1 -= abs_idx_step; - - poly_offset_int limit = idx_len1 + idx_access1 - 1 + idx_access2 - 1; - if (!waw_or_war_p) - limit += idx_len2; - - tree utype = unsigned_type_for (TREE_TYPE (min1)); - if (!wi::fits_to_tree_p (limit, utype)) - return false; - - poly_offset_int low_offset1 = neg_step ? -idx_len1 : 0; - poly_offset_int high_offset2 = neg_step || waw_or_war_p ? 0 : idx_len2; - poly_offset_int bias = high_offset2 + idx_access2 - 1 - low_offset1; - /* Equivalent to adding IDX_STEP to MIN1. */ - if (waw_or_war_p) - bias -= wi::to_offset (idx_step); - - tree subject = fold_build2 (MINUS_EXPR, utype, - fold_convert (utype, min2), - fold_convert (utype, min1)); - subject = fold_build2 (PLUS_EXPR, utype, subject, - wide_int_to_tree (utype, bias)); - tree part_cond_expr = fold_build2 (GT_EXPR, boolean_type_node, subject, - wide_int_to_tree (utype, limit)); - if (*cond_expr) - *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, - *cond_expr, part_cond_expr); - else - *cond_expr = part_cond_expr; - if (dump_enabled_p ()) - { - if (waw_or_war_p) - dump_printf (MSG_NOTE, "using an index-based WAR/WAW test\n"); - else - dump_printf (MSG_NOTE, "using an index-based overlap test\n"); - } - return true; -} - -/* A subroutine of create_intersect_range_checks, with a subset of the - same arguments. Try to optimize cases in which the second access - is a write and in which some overlap is valid. */ - -static bool -create_waw_or_war_checks (tree *cond_expr, - const dr_with_seg_len_pair_t &alias_pair) -{ - const dr_with_seg_len& dr_a = alias_pair.first; - const dr_with_seg_len& dr_b = alias_pair.second; - - /* Check for cases in which: - - (a) DR_B is always a write; - (b) the accesses are well-ordered in both the original and new code - (see the comment above the DR_ALIAS_* flags for details); and - (c) the DR_STEPs describe all access pairs covered by ALIAS_PAIR. */ - if (alias_pair.flags & ~(DR_ALIAS_WAR | DR_ALIAS_WAW)) - return false; - - /* Check for equal (but possibly variable) steps. */ - tree step = DR_STEP (dr_a.dr); - if (!operand_equal_p (step, DR_STEP (dr_b.dr))) - return false; - - /* Make sure that we can operate on sizetype without loss of precision. */ - tree addr_type = TREE_TYPE (DR_BASE_ADDRESS (dr_a.dr)); - if (TYPE_PRECISION (addr_type) != TYPE_PRECISION (sizetype)) - return false; - - /* All addresses involved are known to have a common alignment ALIGN. - We can therefore subtract ALIGN from an exclusive endpoint to get - an inclusive endpoint. In the best (and common) case, ALIGN is the - same as the access sizes of both DRs, and so subtracting ALIGN - cancels out the addition of an access size. */ - unsigned int align = MIN (dr_a.align, dr_b.align); - poly_uint64 last_chunk_a = dr_a.access_size - align; - poly_uint64 last_chunk_b = dr_b.access_size - align; - - /* Get a boolean expression that is true when the step is negative. */ - tree indicator = dr_direction_indicator (dr_a.dr); - tree neg_step = fold_build2 (LT_EXPR, boolean_type_node, - fold_convert (ssizetype, indicator), - ssize_int (0)); - - /* Get lengths in sizetype. */ - tree seg_len_a - = fold_convert (sizetype, rewrite_to_non_trapping_overflow (dr_a.seg_len)); - step = fold_convert (sizetype, rewrite_to_non_trapping_overflow (step)); - - /* Each access has the following pattern: - - <- |seg_len| -> - <--- A: -ve step ---> - +-----+-------+-----+-------+-----+ - | n-1 | ..... | 0 | ..... | n-1 | - +-----+-------+-----+-------+-----+ - <--- B: +ve step ---> - <- |seg_len| -> - | - base address - - where "n" is the number of scalar iterations covered by the segment. - - A is the range of bytes accessed when the step is negative, - B is the range when the step is positive. - - We know that DR_B is a write. We also know (from checking that - DR_A and DR_B are well-ordered) that for each i in [0, n-1], - the write performed by access i of DR_B occurs after access numbers - j<=i of DR_A in both the original and the new code. Any write or - anti dependencies wrt those DR_A accesses are therefore maintained. - - We just need to make sure that each individual write in DR_B does not - overlap any higher-indexed access in DR_A; such DR_A accesses happen - after the DR_B access in the original code but happen before it in - the new code. - - We know the steps for both accesses are equal, so by induction, we - just need to test whether the first write of DR_B overlaps a later - access of DR_A. In other words, we need to move addr_a along by - one iteration: - - addr_a' = addr_a + step - - and check whether: - - [addr_b, addr_b + last_chunk_b] - - overlaps: - - [addr_a' + low_offset_a, addr_a' + high_offset_a + last_chunk_a] - - where [low_offset_a, high_offset_a] spans accesses [1, n-1]. I.e.: - - low_offset_a = +ve step ? 0 : seg_len_a - step - high_offset_a = +ve step ? seg_len_a - step : 0 - - This is equivalent to testing whether: - - addr_a' + low_offset_a <= addr_b + last_chunk_b - && addr_b <= addr_a' + high_offset_a + last_chunk_a - - Converting this into a single test, there is an overlap if: - - 0 <= addr_b + last_chunk_b - addr_a' - low_offset_a <= limit - - where limit = high_offset_a - low_offset_a + last_chunk_a + last_chunk_b - - If DR_A is performed, limit + |step| - last_chunk_b is known to be - less than the size of the object underlying DR_A. We also know - that last_chunk_b <= |step|; this is checked elsewhere if it isn't - guaranteed at compile time. There can therefore be no overflow if - "limit" is calculated in an unsigned type with pointer precision. */ - tree addr_a = fold_build_pointer_plus (DR_BASE_ADDRESS (dr_a.dr), - DR_OFFSET (dr_a.dr)); - addr_a = fold_build_pointer_plus (addr_a, DR_INIT (dr_a.dr)); - - tree addr_b = fold_build_pointer_plus (DR_BASE_ADDRESS (dr_b.dr), - DR_OFFSET (dr_b.dr)); - addr_b = fold_build_pointer_plus (addr_b, DR_INIT (dr_b.dr)); - - /* Advance ADDR_A by one iteration and adjust the length to compensate. */ - addr_a = fold_build_pointer_plus (addr_a, step); - tree seg_len_a_minus_step = fold_build2 (MINUS_EXPR, sizetype, - seg_len_a, step); - if (!CONSTANT_CLASS_P (seg_len_a_minus_step)) - seg_len_a_minus_step = build1 (SAVE_EXPR, sizetype, seg_len_a_minus_step); - - tree low_offset_a = fold_build3 (COND_EXPR, sizetype, neg_step, - seg_len_a_minus_step, size_zero_node); - if (!CONSTANT_CLASS_P (low_offset_a)) - low_offset_a = build1 (SAVE_EXPR, sizetype, low_offset_a); - - /* We could use COND_EXPR <neg_step, size_zero_node, seg_len_a_minus_step>, - but it's usually more efficient to reuse the LOW_OFFSET_A result. */ - tree high_offset_a = fold_build2 (MINUS_EXPR, sizetype, seg_len_a_minus_step, - low_offset_a); - - /* The amount added to addr_b - addr_a'. */ - tree bias = fold_build2 (MINUS_EXPR, sizetype, - size_int (last_chunk_b), low_offset_a); - - tree limit = fold_build2 (MINUS_EXPR, sizetype, high_offset_a, low_offset_a); - limit = fold_build2 (PLUS_EXPR, sizetype, limit, - size_int (last_chunk_a + last_chunk_b)); - - tree subject = fold_build2 (POINTER_DIFF_EXPR, ssizetype, addr_b, addr_a); - subject = fold_build2 (PLUS_EXPR, sizetype, - fold_convert (sizetype, subject), bias); - - *cond_expr = fold_build2 (GT_EXPR, boolean_type_node, subject, limit); - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, "using an address-based WAR/WAW test\n"); - return true; -} - -/* If ALIGN is nonzero, set up *SEQ_MIN_OUT and *SEQ_MAX_OUT so that for - every address ADDR accessed by D: - - *SEQ_MIN_OUT <= ADDR (== ADDR & -ALIGN) <= *SEQ_MAX_OUT - - In this case, every element accessed by D is aligned to at least - ALIGN bytes. - - If ALIGN is zero then instead set *SEG_MAX_OUT so that: - - *SEQ_MIN_OUT <= ADDR < *SEQ_MAX_OUT. */ - -static void -get_segment_min_max (const dr_with_seg_len &d, tree *seg_min_out, - tree *seg_max_out, HOST_WIDE_INT align) -{ - /* Each access has the following pattern: - - <- |seg_len| -> - <--- A: -ve step ---> - +-----+-------+-----+-------+-----+ - | n-1 | ,.... | 0 | ..... | n-1 | - +-----+-------+-----+-------+-----+ - <--- B: +ve step ---> - <- |seg_len| -> - | - base address - - where "n" is the number of scalar iterations covered by the segment. - (This should be VF for a particular pair if we know that both steps - are the same, otherwise it will be the full number of scalar loop - iterations.) - - A is the range of bytes accessed when the step is negative, - B is the range when the step is positive. - - If the access size is "access_size" bytes, the lowest addressed byte is: - - base + (step < 0 ? seg_len : 0) [LB] - - and the highest addressed byte is always below: - - base + (step < 0 ? 0 : seg_len) + access_size [UB] - - Thus: - - LB <= ADDR < UB - - If ALIGN is nonzero, all three values are aligned to at least ALIGN - bytes, so: - - LB <= ADDR <= UB - ALIGN - - where "- ALIGN" folds naturally with the "+ access_size" and often - cancels it out. - - We don't try to simplify LB and UB beyond this (e.g. by using - MIN and MAX based on whether seg_len rather than the stride is - negative) because it is possible for the absolute size of the - segment to overflow the range of a ssize_t. - - Keeping the pointer_plus outside of the cond_expr should allow - the cond_exprs to be shared with other alias checks. */ - tree indicator = dr_direction_indicator (d.dr); - tree neg_step = fold_build2 (LT_EXPR, boolean_type_node, - fold_convert (ssizetype, indicator), - ssize_int (0)); - tree addr_base = fold_build_pointer_plus (DR_BASE_ADDRESS (d.dr), - DR_OFFSET (d.dr)); - addr_base = fold_build_pointer_plus (addr_base, DR_INIT (d.dr)); - tree seg_len - = fold_convert (sizetype, rewrite_to_non_trapping_overflow (d.seg_len)); - - tree min_reach = fold_build3 (COND_EXPR, sizetype, neg_step, - seg_len, size_zero_node); - tree max_reach = fold_build3 (COND_EXPR, sizetype, neg_step, - size_zero_node, seg_len); - max_reach = fold_build2 (PLUS_EXPR, sizetype, max_reach, - size_int (d.access_size - align)); - - *seg_min_out = fold_build_pointer_plus (addr_base, min_reach); - *seg_max_out = fold_build_pointer_plus (addr_base, max_reach); -} - -/* Generate a runtime condition that is true if ALIAS_PAIR is free of aliases, - storing the condition in *COND_EXPR. The fallback is to generate a - a test that the two accesses do not overlap: - - end_a <= start_b || end_b <= start_a. */ - -static void -create_intersect_range_checks (class loop *loop, tree *cond_expr, - const dr_with_seg_len_pair_t &alias_pair) -{ - const dr_with_seg_len& dr_a = alias_pair.first; - const dr_with_seg_len& dr_b = alias_pair.second; - *cond_expr = NULL_TREE; - if (create_intersect_range_checks_index (loop, cond_expr, alias_pair)) - return; - - if (create_ifn_alias_checks (cond_expr, alias_pair)) - return; - - if (create_waw_or_war_checks (cond_expr, alias_pair)) - return; - - unsigned HOST_WIDE_INT min_align; - tree_code cmp_code; - /* We don't have to check DR_ALIAS_MIXED_STEPS here, since both versions - are equivalent. This is just an optimization heuristic. */ - if (TREE_CODE (DR_STEP (dr_a.dr)) == INTEGER_CST - && TREE_CODE (DR_STEP (dr_b.dr)) == INTEGER_CST) - { - /* In this case adding access_size to seg_len is likely to give - a simple X * step, where X is either the number of scalar - iterations or the vectorization factor. We're better off - keeping that, rather than subtracting an alignment from it. - - In this case the maximum values are exclusive and so there is - no alias if the maximum of one segment equals the minimum - of another. */ - min_align = 0; - cmp_code = LE_EXPR; - } - else - { - /* Calculate the minimum alignment shared by all four pointers, - then arrange for this alignment to be subtracted from the - exclusive maximum values to get inclusive maximum values. - This "- min_align" is cumulative with a "+ access_size" - in the calculation of the maximum values. In the best - (and common) case, the two cancel each other out, leaving - us with an inclusive bound based only on seg_len. In the - worst case we're simply adding a smaller number than before. - - Because the maximum values are inclusive, there is an alias - if the maximum value of one segment is equal to the minimum - value of the other. */ - min_align = MIN (dr_a.align, dr_b.align); - cmp_code = LT_EXPR; - } - - tree seg_a_min, seg_a_max, seg_b_min, seg_b_max; - get_segment_min_max (dr_a, &seg_a_min, &seg_a_max, min_align); - get_segment_min_max (dr_b, &seg_b_min, &seg_b_max, min_align); - - *cond_expr - = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, - fold_build2 (cmp_code, boolean_type_node, seg_a_max, seg_b_min), - fold_build2 (cmp_code, boolean_type_node, seg_b_max, seg_a_min)); - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, "using an address-based overlap test\n"); -} - -/* Create a conditional expression that represents the run-time checks for - overlapping of address ranges represented by a list of data references - pairs passed in ALIAS_PAIRS. Data references are in LOOP. The returned - COND_EXPR is the conditional expression to be used in the if statement - that controls which version of the loop gets executed at runtime. */ - -void -create_runtime_alias_checks (class loop *loop, - const vec<dr_with_seg_len_pair_t> *alias_pairs, - tree * cond_expr) -{ - tree part_cond_expr; - - fold_defer_overflow_warnings (); - for (const dr_with_seg_len_pair_t &alias_pair : alias_pairs) - { - gcc_assert (alias_pair.flags); - if (dump_enabled_p ()) - dump_printf (MSG_NOTE, - "create runtime check for data references %T and %T\n", - DR_REF (alias_pair.first.dr), - DR_REF (alias_pair.second.dr)); - - /* Create condition expression for each pair data references. */ - create_intersect_range_checks (loop, &part_cond_expr, alias_pair); - if (*cond_expr) - *cond_expr = fold_build2 (TRUTH_AND_EXPR, boolean_type_node, - *cond_expr, part_cond_expr); - else - *cond_expr = part_cond_expr; - } - fold_undefer_and_ignore_overflow_warnings (); -} - -/* Check if OFFSET1 and OFFSET2 (DR_OFFSETs of some data-refs) are identical - expressions. */ -static bool -dr_equal_offsets_p1 (tree offset1, tree offset2) -{ - bool res; - - STRIP_NOPS (offset1); - STRIP_NOPS (offset2); - - if (offset1 == offset2) - return true; - - if (TREE_CODE (offset1) != TREE_CODE (offset2) - || (!BINARY_CLASS_P (offset1) && !UNARY_CLASS_P (offset1))) - return false; - - res = dr_equal_offsets_p1 (TREE_OPERAND (offset1, 0), - TREE_OPERAND (offset2, 0)); - - if (!res || !BINARY_CLASS_P (offset1)) - return res; - - res = dr_equal_offsets_p1 (TREE_OPERAND (offset1, 1), - TREE_OPERAND (offset2, 1)); - - return res; -} - -/* Check if DRA and DRB have equal offsets. */ -bool -dr_equal_offsets_p (struct data_reference *dra, - struct data_reference *drb) -{ - tree offset1, offset2; - - offset1 = DR_OFFSET (dra); - offset2 = DR_OFFSET (drb); - - return dr_equal_offsets_p1 (offset1, offset2); -} - -/* Returns true if FNA == FNB. */ - -static bool -affine_function_equal_p (affine_fn fna, affine_fn fnb) -{ - unsigned i, n = fna.length (); - - if (n != fnb.length ()) - return false; - - for (i = 0; i < n; i++) - if (!operand_equal_p (fna[i], fnb[i], 0)) - return false; - - return true; -} - -/* If all the functions in CF are the same, returns one of them, - otherwise returns NULL. */ - -static affine_fn -common_affine_function (conflict_function *cf) -{ - unsigned i; - affine_fn comm; - - if (!CF_NONTRIVIAL_P (cf)) - return affine_fn (); - - comm = cf->fns[0]; - - for (i = 1; i < cf->n; i++) - if (!affine_function_equal_p (comm, cf->fns[i])) - return affine_fn (); - - return comm; -} - -/* Returns the base of the affine function FN. */ - -static tree -affine_function_base (affine_fn fn) -{ - return fn[0]; -} - -/* Returns true if FN is a constant. */ - -static bool -affine_function_constant_p (affine_fn fn) -{ - unsigned i; - tree coef; - - for (i = 1; fn.iterate (i, &coef); i++) - if (!integer_zerop (coef)) - return false; - - return true; -} - -/* Returns true if FN is the zero constant function. */ - -static bool -affine_function_zero_p (affine_fn fn) -{ - return (integer_zerop (affine_function_base (fn)) - && affine_function_constant_p (fn)); -} - -/* Returns a signed integer type with the largest precision from TA - and TB. */ - -static tree -signed_type_for_types (tree ta, tree tb) -{ - if (TYPE_PRECISION (ta) > TYPE_PRECISION (tb)) - return signed_type_for (ta); - else - return signed_type_for (tb); -} - -/* Applies operation OP on affine functions FNA and FNB, and returns the - result. */ - -static affine_fn -affine_fn_op (enum tree_code op, affine_fn fna, affine_fn fnb) -{ - unsigned i, n, m; - affine_fn ret; - tree coef; - - if (fnb.length () > fna.length ()) - { - n = fna.length (); - m = fnb.length (); - } - else - { - n = fnb.length (); - m = fna.length (); - } - - ret.create (m); - for (i = 0; i < n; i++) - { - tree type = signed_type_for_types (TREE_TYPE (fna[i]), - TREE_TYPE (fnb[i])); - ret.quick_push (fold_build2 (op, type, fna[i], fnb[i])); - } - - for (; fna.iterate (i, &coef); i++) - ret.quick_push (fold_build2 (op, signed_type_for (TREE_TYPE (coef)), - coef, integer_zero_node)); - for (; fnb.iterate (i, &coef); i++) - ret.quick_push (fold_build2 (op, signed_type_for (TREE_TYPE (coef)), - integer_zero_node, coef)); - - return ret; -} - -/* Returns the sum of affine functions FNA and FNB. */ - -static affine_fn -affine_fn_plus (affine_fn fna, affine_fn fnb) -{ - return affine_fn_op (PLUS_EXPR, fna, fnb); -} - -/* Returns the difference of affine functions FNA and FNB. */ - -static affine_fn -affine_fn_minus (affine_fn fna, affine_fn fnb) -{ - return affine_fn_op (MINUS_EXPR, fna, fnb); -} - -/* Frees affine function FN. */ - -static void -affine_fn_free (affine_fn fn) -{ - fn.release (); -} - -/* Determine for each subscript in the data dependence relation DDR - the distance. */ - -static void -compute_subscript_distance (struct data_dependence_relation *ddr) -{ - conflict_function *cf_a, *cf_b; - affine_fn fn_a, fn_b, diff; - - if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) - { - unsigned int i; - - for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) - { - struct subscript *subscript; - - subscript = DDR_SUBSCRIPT (ddr, i); - cf_a = SUB_CONFLICTS_IN_A (subscript); - cf_b = SUB_CONFLICTS_IN_B (subscript); - - fn_a = common_affine_function (cf_a); - fn_b = common_affine_function (cf_b); - if (!fn_a.exists () || !fn_b.exists ()) - { - SUB_DISTANCE (subscript) = chrec_dont_know; - return; - } - diff = affine_fn_minus (fn_a, fn_b); - - if (affine_function_constant_p (diff)) - SUB_DISTANCE (subscript) = affine_function_base (diff); - else - SUB_DISTANCE (subscript) = chrec_dont_know; - - affine_fn_free (diff); - } - } -} - -/* Returns the conflict function for "unknown". */ - -static conflict_function * -conflict_fn_not_known (void) -{ - conflict_function *fn = XCNEW (conflict_function); - fn->n = NOT_KNOWN; - - return fn; -} - -/* Returns the conflict function for "independent". */ - -static conflict_function * -conflict_fn_no_dependence (void) -{ - conflict_function *fn = XCNEW (conflict_function); - fn->n = NO_DEPENDENCE; - - return fn; -} - -/* Returns true if the address of OBJ is invariant in LOOP. */ - -static bool -object_address_invariant_in_loop_p (const class loop *loop, const_tree obj) -{ - while (handled_component_p (obj)) - { - if (TREE_CODE (obj) == ARRAY_REF) - { - for (int i = 1; i < 4; ++i) - if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, i), - loop->num)) - return false; - } - else if (TREE_CODE (obj) == COMPONENT_REF) - { - if (chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 2), - loop->num)) - return false; - } - obj = TREE_OPERAND (obj, 0); - } - - if (!INDIRECT_REF_P (obj) - && TREE_CODE (obj) != MEM_REF) - return true; - - return !chrec_contains_symbols_defined_in_loop (TREE_OPERAND (obj, 0), - loop->num); -} - -/* Returns false if we can prove that data references A and B do not alias, - true otherwise. If LOOP_NEST is false no cross-iteration aliases are - considered. */ - -bool -dr_may_alias_p (const struct data_reference *a, const struct data_reference *b, - class loop *loop_nest) -{ - tree addr_a = DR_BASE_OBJECT (a); - tree addr_b = DR_BASE_OBJECT (b); - - /* If we are not processing a loop nest but scalar code we - do not need to care about possible cross-iteration dependences - and thus can process the full original reference. Do so, - similar to how loop invariant motion applies extra offset-based - disambiguation. */ - if (!loop_nest) - { - aff_tree off1, off2; - poly_widest_int size1, size2; - get_inner_reference_aff (DR_REF (a), &off1, &size1); - get_inner_reference_aff (DR_REF (b), &off2, &size2); - aff_combination_scale (&off1, -1); - aff_combination_add (&off2, &off1); - if (aff_comb_cannot_overlap_p (&off2, size1, size2)) - return false; - } - - if ((TREE_CODE (addr_a) == MEM_REF || TREE_CODE (addr_a) == TARGET_MEM_REF) - && (TREE_CODE (addr_b) == MEM_REF || TREE_CODE (addr_b) == TARGET_MEM_REF) - /* For cross-iteration dependences the cliques must be valid for the - whole loop, not just individual iterations. */ - && (!loop_nest - || MR_DEPENDENCE_CLIQUE (addr_a) == 1 - || MR_DEPENDENCE_CLIQUE (addr_a) == loop_nest->owned_clique) - && MR_DEPENDENCE_CLIQUE (addr_a) == MR_DEPENDENCE_CLIQUE (addr_b) - && MR_DEPENDENCE_BASE (addr_a) != MR_DEPENDENCE_BASE (addr_b)) - return false; - - /* If we had an evolution in a pointer-based MEM_REF BASE_OBJECT we - do not know the size of the base-object. So we cannot do any - offset/overlap based analysis but have to rely on points-to - information only. */ - if (TREE_CODE (addr_a) == MEM_REF - && (DR_UNCONSTRAINED_BASE (a) - || TREE_CODE (TREE_OPERAND (addr_a, 0)) == SSA_NAME)) - { - /* For true dependences we can apply TBAA. */ - if (flag_strict_aliasing - && DR_IS_WRITE (a) && DR_IS_READ (b) - && !alias_sets_conflict_p (get_alias_set (DR_REF (a)), - get_alias_set (DR_REF (b)))) - return false; - if (TREE_CODE (addr_b) == MEM_REF) - return ptr_derefs_may_alias_p (TREE_OPERAND (addr_a, 0), - TREE_OPERAND (addr_b, 0)); - else - return ptr_derefs_may_alias_p (TREE_OPERAND (addr_a, 0), - build_fold_addr_expr (addr_b)); - } - else if (TREE_CODE (addr_b) == MEM_REF - && (DR_UNCONSTRAINED_BASE (b) - || TREE_CODE (TREE_OPERAND (addr_b, 0)) == SSA_NAME)) - { - /* For true dependences we can apply TBAA. */ - if (flag_strict_aliasing - && DR_IS_WRITE (a) && DR_IS_READ (b) - && !alias_sets_conflict_p (get_alias_set (DR_REF (a)), - get_alias_set (DR_REF (b)))) - return false; - if (TREE_CODE (addr_a) == MEM_REF) - return ptr_derefs_may_alias_p (TREE_OPERAND (addr_a, 0), - TREE_OPERAND (addr_b, 0)); - else - return ptr_derefs_may_alias_p (build_fold_addr_expr (addr_a), - TREE_OPERAND (addr_b, 0)); - } - - /* Otherwise DR_BASE_OBJECT is an access that covers the whole object - that is being subsetted in the loop nest. */ - if (DR_IS_WRITE (a) && DR_IS_WRITE (b)) - return refs_output_dependent_p (addr_a, addr_b); - else if (DR_IS_READ (a) && DR_IS_WRITE (b)) - return refs_anti_dependent_p (addr_a, addr_b); - return refs_may_alias_p (addr_a, addr_b); -} - -/* REF_A and REF_B both satisfy access_fn_component_p. Return true - if it is meaningful to compare their associated access functions - when checking for dependencies. */ - -static bool -access_fn_components_comparable_p (tree ref_a, tree ref_b) -{ - /* Allow pairs of component refs from the following sets: - - { REALPART_EXPR, IMAGPART_EXPR } - { COMPONENT_REF } - { ARRAY_REF }. */ - tree_code code_a = TREE_CODE (ref_a); - tree_code code_b = TREE_CODE (ref_b); - if (code_a == IMAGPART_EXPR) - code_a = REALPART_EXPR; - if (code_b == IMAGPART_EXPR) - code_b = REALPART_EXPR; - if (code_a != code_b) - return false; - - if (TREE_CODE (ref_a) == COMPONENT_REF) - /* ??? We cannot simply use the type of operand #0 of the refs here as - the Fortran compiler smuggles type punning into COMPONENT_REFs. - Use the DECL_CONTEXT of the FIELD_DECLs instead. */ - return (DECL_CONTEXT (TREE_OPERAND (ref_a, 1)) - == DECL_CONTEXT (TREE_OPERAND (ref_b, 1))); - - return types_compatible_p (TREE_TYPE (TREE_OPERAND (ref_a, 0)), - TREE_TYPE (TREE_OPERAND (ref_b, 0))); -} - -/* Initialize a data dependence relation RES in LOOP_NEST. USE_ALT_INDICES - is true when the main indices of A and B were not comparable so we try again - with alternate indices computed on an indirect reference. */ - -struct data_dependence_relation * -initialize_data_dependence_relation (struct data_dependence_relation *res, - vec<loop_p> loop_nest, - bool use_alt_indices) -{ - struct data_reference *a = DDR_A (res); - struct data_reference *b = DDR_B (res); - unsigned int i; - - struct indices *indices_a = &a->indices; - struct indices *indices_b = &b->indices; - if (use_alt_indices) - { - if (TREE_CODE (DR_REF (a)) != MEM_REF) - indices_a = &a->alt_indices; - if (TREE_CODE (DR_REF (b)) != MEM_REF) - indices_b = &b->alt_indices; - } - unsigned int num_dimensions_a = indices_a->access_fns.length (); - unsigned int num_dimensions_b = indices_b->access_fns.length (); - if (num_dimensions_a == 0 || num_dimensions_b == 0) - { - DDR_ARE_DEPENDENT (res) = chrec_dont_know; - return res; - } - - /* For unconstrained bases, the root (highest-indexed) subscript - describes a variation in the base of the original DR_REF rather - than a component access. We have no type that accurately describes - the new DR_BASE_OBJECT (whose TREE_TYPE describes the type *after* - applying this subscript) so limit the search to the last real - component access. - - E.g. for: - - void - f (int a[][8], int b[][8]) - { - for (int i = 0; i < 8; ++i) - a[i * 2][0] = b[i][0]; - } - - the a and b accesses have a single ARRAY_REF component reference [0] - but have two subscripts. */ - if (indices_a->unconstrained_base) - num_dimensions_a -= 1; - if (indices_b->unconstrained_base) - num_dimensions_b -= 1; - - /* These structures describe sequences of component references in - DR_REF (A) and DR_REF (B). Each component reference is tied to a - specific access function. */ - struct { - /* The sequence starts at DR_ACCESS_FN (A, START_A) of A and - DR_ACCESS_FN (B, START_B) of B (inclusive) and extends to higher - indices. In C notation, these are the indices of the rightmost - component references; e.g. for a sequence .b.c.d, the start - index is for .d. */ - unsigned int start_a; - unsigned int start_b; - - /* The sequence contains LENGTH consecutive access functions from - each DR. */ - unsigned int length; - - /* The enclosing objects for the A and B sequences respectively, - i.e. the objects to which DR_ACCESS_FN (A, START_A + LENGTH - 1) - and DR_ACCESS_FN (B, START_B + LENGTH - 1) are applied. */ - tree object_a; - tree object_b; - } full_seq = {}, struct_seq = {}; - - /* Before each iteration of the loop: - - - REF_A is what you get after applying DR_ACCESS_FN (A, INDEX_A) and - - REF_B is what you get after applying DR_ACCESS_FN (B, INDEX_B). */ - unsigned int index_a = 0; - unsigned int index_b = 0; - tree ref_a = DR_REF (a); - tree ref_b = DR_REF (b); - - /* Now walk the component references from the final DR_REFs back up to - the enclosing base objects. Each component reference corresponds - to one access function in the DR, with access function 0 being for - the final DR_REF and the highest-indexed access function being the - one that is applied to the base of the DR. - - Look for a sequence of component references whose access functions - are comparable (see access_fn_components_comparable_p). If more - than one such sequence exists, pick the one nearest the base - (which is the leftmost sequence in C notation). Store this sequence - in FULL_SEQ. - - For example, if we have: - - struct foo { struct bar s; ... } (*a)[10], (*b)[10]; - - A: a[0][i].s.c.d - B: __real b[0][i].s.e[i].f - - (where d is the same type as the real component of f) then the access - functions would be: - - 0 1 2 3 - A: .d .c .s [i] - - 0 1 2 3 4 5 - B: __real .f [i] .e .s [i] - - The A0/B2 column isn't comparable, since .d is a COMPONENT_REF - and [i] is an ARRAY_REF. However, the A1/B3 column contains two - COMPONENT_REF accesses for struct bar, so is comparable. Likewise - the A2/B4 column contains two COMPONENT_REF accesses for struct foo, - so is comparable. The A3/B5 column contains two ARRAY_REFs that - index foo[10] arrays, so is again comparable. The sequence is - therefore: - - A: [1, 3] (i.e. [i].s.c) - B: [3, 5] (i.e. [i].s.e) - - Also look for sequences of component references whose access - functions are comparable and whose enclosing objects have the same - RECORD_TYPE. Store this sequence in STRUCT_SEQ. In the above - example, STRUCT_SEQ would be: - - A: [1, 2] (i.e. s.c) - B: [3, 4] (i.e. s.e) */ - while (index_a < num_dimensions_a && index_b < num_dimensions_b) - { - /* The alternate indices form always has a single dimension - with unconstrained base. */ - gcc_assert (!use_alt_indices); - - /* REF_A and REF_B must be one of the component access types - allowed by dr_analyze_indices. */ - gcc_checking_assert (access_fn_component_p (ref_a)); - gcc_checking_assert (access_fn_component_p (ref_b)); - - /* Get the immediately-enclosing objects for REF_A and REF_B, - i.e. the references *before* applying DR_ACCESS_FN (A, INDEX_A) - and DR_ACCESS_FN (B, INDEX_B). */ - tree object_a = TREE_OPERAND (ref_a, 0); - tree object_b = TREE_OPERAND (ref_b, 0); - - tree type_a = TREE_TYPE (object_a); - tree type_b = TREE_TYPE (object_b); - if (access_fn_components_comparable_p (ref_a, ref_b)) - { - /* This pair of component accesses is comparable for dependence - analysis, so we can include DR_ACCESS_FN (A, INDEX_A) and - DR_ACCESS_FN (B, INDEX_B) in the sequence. */ - if (full_seq.start_a + full_seq.length != index_a - || full_seq.start_b + full_seq.length != index_b) - { - /* The accesses don't extend the current sequence, - so start a new one here. */ - full_seq.start_a = index_a; - full_seq.start_b = index_b; - full_seq.length = 0; - } - - /* Add this pair of references to the sequence. */ - full_seq.length += 1; - full_seq.object_a = object_a; - full_seq.object_b = object_b; - - /* If the enclosing objects are structures (and thus have the - same RECORD_TYPE), record the new sequence in STRUCT_SEQ. */ - if (TREE_CODE (type_a) == RECORD_TYPE) - struct_seq = full_seq; - - /* Move to the next containing reference for both A and B. */ - ref_a = object_a; - ref_b = object_b; - index_a += 1; - index_b += 1; - continue; - } - - /* Try to approach equal type sizes. */ - if (!COMPLETE_TYPE_P (type_a) - || !COMPLETE_TYPE_P (type_b) - || !tree_fits_uhwi_p (TYPE_SIZE_UNIT (type_a)) - || !tree_fits_uhwi_p (TYPE_SIZE_UNIT (type_b))) - break; - - unsigned HOST_WIDE_INT size_a = tree_to_uhwi (TYPE_SIZE_UNIT (type_a)); - unsigned HOST_WIDE_INT size_b = tree_to_uhwi (TYPE_SIZE_UNIT (type_b)); - if (size_a <= size_b) - { - index_a += 1; - ref_a = object_a; - } - if (size_b <= size_a) - { - index_b += 1; - ref_b = object_b; - } - } - - /* See whether FULL_SEQ ends at the base and whether the two bases - are equal. We do not care about TBAA or alignment info so we can - use OEP_ADDRESS_OF to avoid false negatives. */ - tree base_a = indices_a->base_object; - tree base_b = indices_b->base_object; - bool same_base_p = (full_seq.start_a + full_seq.length == num_dimensions_a - && full_seq.start_b + full_seq.length == num_dimensions_b - && (indices_a->unconstrained_base - == indices_b->unconstrained_base) - && operand_equal_p (base_a, base_b, OEP_ADDRESS_OF) - && (types_compatible_p (TREE_TYPE (base_a), - TREE_TYPE (base_b)) - || (!base_supports_access_fn_components_p (base_a) - && !base_supports_access_fn_components_p (base_b) - && operand_equal_p - (TYPE_SIZE (TREE_TYPE (base_a)), - TYPE_SIZE (TREE_TYPE (base_b)), 0))) - && (!loop_nest.exists () - || (object_address_invariant_in_loop_p - (loop_nest[0], base_a)))); - - /* If the bases are the same, we can include the base variation too. - E.g. the b accesses in: - - for (int i = 0; i < n; ++i) - b[i + 4][0] = b[i][0]; - - have a definite dependence distance of 4, while for: - - for (int i = 0; i < n; ++i) - a[i + 4][0] = b[i][0]; - - the dependence distance depends on the gap between a and b. - - If the bases are different then we can only rely on the sequence - rooted at a structure access, since arrays are allowed to overlap - arbitrarily and change shape arbitrarily. E.g. we treat this as - valid code: - - int a[256]; - ... - ((int (*)[4][3]) &a[1])[i][0] += ((int (*)[4][3]) &a[2])[i][0]; - - where two lvalues with the same int[4][3] type overlap, and where - both lvalues are distinct from the object's declared type. */ - if (same_base_p) - { - if (indices_a->unconstrained_base) - full_seq.length += 1; - } - else - full_seq = struct_seq; - - /* Punt if we didn't find a suitable sequence. */ - if (full_seq.length == 0) - { - if (use_alt_indices - || (TREE_CODE (DR_REF (a)) == MEM_REF - && TREE_CODE (DR_REF (b)) == MEM_REF) - || may_be_nonaddressable_p (DR_REF (a)) - || may_be_nonaddressable_p (DR_REF (b))) - { - /* Fully exhausted possibilities. */ - DDR_ARE_DEPENDENT (res) = chrec_dont_know; - return res; - } - - /* Try evaluating both DRs as dereferences of pointers. */ - if (!a->alt_indices.base_object - && TREE_CODE (DR_REF (a)) != MEM_REF) - { - tree alt_ref = build2 (MEM_REF, TREE_TYPE (DR_REF (a)), - build1 (ADDR_EXPR, ptr_type_node, DR_REF (a)), - build_int_cst - (reference_alias_ptr_type (DR_REF (a)), 0)); - dr_analyze_indices (&a->alt_indices, alt_ref, - loop_preheader_edge (loop_nest[0]), - loop_containing_stmt (DR_STMT (a))); - } - if (!b->alt_indices.base_object - && TREE_CODE (DR_REF (b)) != MEM_REF) - { - tree alt_ref = build2 (MEM_REF, TREE_TYPE (DR_REF (b)), - build1 (ADDR_EXPR, ptr_type_node, DR_REF (b)), - build_int_cst - (reference_alias_ptr_type (DR_REF (b)), 0)); - dr_analyze_indices (&b->alt_indices, alt_ref, - loop_preheader_edge (loop_nest[0]), - loop_containing_stmt (DR_STMT (b))); - } - return initialize_data_dependence_relation (res, loop_nest, true); - } - - if (!same_base_p) - { - /* Partial overlap is possible for different bases when strict aliasing - is not in effect. It's also possible if either base involves a union - access; e.g. for: - - struct s1 { int a[2]; }; - struct s2 { struct s1 b; int c; }; - struct s3 { int d; struct s1 e; }; - union u { struct s2 f; struct s3 g; } *p, *q; - - the s1 at "p->f.b" (base "p->f") partially overlaps the s1 at - "p->g.e" (base "p->g") and might partially overlap the s1 at - "q->g.e" (base "q->g"). */ - if (!flag_strict_aliasing - || ref_contains_union_access_p (full_seq.object_a) - || ref_contains_union_access_p (full_seq.object_b)) - { - DDR_ARE_DEPENDENT (res) = chrec_dont_know; - return res; - } - - DDR_COULD_BE_INDEPENDENT_P (res) = true; - if (!loop_nest.exists () - || (object_address_invariant_in_loop_p (loop_nest[0], - full_seq.object_a) - && object_address_invariant_in_loop_p (loop_nest[0], - full_seq.object_b))) - { - DDR_OBJECT_A (res) = full_seq.object_a; - DDR_OBJECT_B (res) = full_seq.object_b; - } - } - - DDR_AFFINE_P (res) = true; - DDR_ARE_DEPENDENT (res) = NULL_TREE; - DDR_SUBSCRIPTS (res).create (full_seq.length); - DDR_LOOP_NEST (res) = loop_nest; - DDR_SELF_REFERENCE (res) = false; - - for (i = 0; i < full_seq.length; ++i) - { - struct subscript *subscript; - - subscript = XNEW (struct subscript); - SUB_ACCESS_FN (subscript, 0) = indices_a->access_fns[full_seq.start_a + i]; - SUB_ACCESS_FN (subscript, 1) = indices_b->access_fns[full_seq.start_b + i]; - SUB_CONFLICTS_IN_A (subscript) = conflict_fn_not_known (); - SUB_CONFLICTS_IN_B (subscript) = conflict_fn_not_known (); - SUB_LAST_CONFLICT (subscript) = chrec_dont_know; - SUB_DISTANCE (subscript) = chrec_dont_know; - DDR_SUBSCRIPTS (res).safe_push (subscript); - } - - return res; -} - -/* Initialize a data dependence relation between data accesses A and - B. NB_LOOPS is the number of loops surrounding the references: the - size of the classic distance/direction vectors. */ - -struct data_dependence_relation * -initialize_data_dependence_relation (struct data_reference *a, - struct data_reference *b, - vec<loop_p> loop_nest) -{ - data_dependence_relation *res = XCNEW (struct data_dependence_relation); - DDR_A (res) = a; - DDR_B (res) = b; - DDR_LOOP_NEST (res).create (0); - DDR_SUBSCRIPTS (res).create (0); - DDR_DIR_VECTS (res).create (0); - DDR_DIST_VECTS (res).create (0); - - if (a == NULL || b == NULL) - { - DDR_ARE_DEPENDENT (res) = chrec_dont_know; - return res; - } - - /* If the data references do not alias, then they are independent. */ - if (!dr_may_alias_p (a, b, loop_nest.exists () ? loop_nest[0] : NULL)) - { - DDR_ARE_DEPENDENT (res) = chrec_known; - return res; - } - - return initialize_data_dependence_relation (res, loop_nest, false); -} - - -/* Frees memory used by the conflict function F. */ - -static void -free_conflict_function (conflict_function *f) -{ - unsigned i; - - if (CF_NONTRIVIAL_P (f)) - { - for (i = 0; i < f->n; i++) - affine_fn_free (f->fns[i]); - } - free (f); -} - -/* Frees memory used by SUBSCRIPTS. */ - -static void -free_subscripts (vec<subscript_p> subscripts) -{ - for (subscript_p s : subscripts) - { - free_conflict_function (s->conflicting_iterations_in_a); - free_conflict_function (s->conflicting_iterations_in_b); - free (s); - } - subscripts.release (); -} - -/* Set DDR_ARE_DEPENDENT to CHREC and finalize the subscript overlap - description. */ - -static inline void -finalize_ddr_dependent (struct data_dependence_relation *ddr, - tree chrec) -{ - DDR_ARE_DEPENDENT (ddr) = chrec; - free_subscripts (DDR_SUBSCRIPTS (ddr)); - DDR_SUBSCRIPTS (ddr).create (0); -} - -/* The dependence relation DDR cannot be represented by a distance - vector. */ - -static inline void -non_affine_dependence_relation (struct data_dependence_relation *ddr) -{ - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "(Dependence relation cannot be represented by distance vector.) \n"); - - DDR_AFFINE_P (ddr) = false; -} - - - -/* This section contains the classic Banerjee tests. */ - -/* Returns true iff CHREC_A and CHREC_B are not dependent on any index - variables, i.e., if the ZIV (Zero Index Variable) test is true. */ - -static inline bool -ziv_subscript_p (const_tree chrec_a, const_tree chrec_b) -{ - return (evolution_function_is_constant_p (chrec_a) - && evolution_function_is_constant_p (chrec_b)); -} - -/* Returns true iff CHREC_A and CHREC_B are dependent on an index - variable, i.e., if the SIV (Single Index Variable) test is true. */ - -static bool -siv_subscript_p (const_tree chrec_a, const_tree chrec_b) -{ - if ((evolution_function_is_constant_p (chrec_a) - && evolution_function_is_univariate_p (chrec_b)) - || (evolution_function_is_constant_p (chrec_b) - && evolution_function_is_univariate_p (chrec_a))) - return true; - - if (evolution_function_is_univariate_p (chrec_a) - && evolution_function_is_univariate_p (chrec_b)) - { - switch (TREE_CODE (chrec_a)) - { - case POLYNOMIAL_CHREC: - switch (TREE_CODE (chrec_b)) - { - case POLYNOMIAL_CHREC: - if (CHREC_VARIABLE (chrec_a) != CHREC_VARIABLE (chrec_b)) - return false; - /* FALLTHRU */ - - default: - return true; - } - - default: - return true; - } - } - - return false; -} - -/* Creates a conflict function with N dimensions. The affine functions - in each dimension follow. */ - -static conflict_function * -conflict_fn (unsigned n, ...) -{ - unsigned i; - conflict_function *ret = XCNEW (conflict_function); - va_list ap; - - gcc_assert (n > 0 && n <= MAX_DIM); - va_start (ap, n); - - ret->n = n; - for (i = 0; i < n; i++) - ret->fns[i] = va_arg (ap, affine_fn); - va_end (ap); - - return ret; -} - -/* Returns constant affine function with value CST. */ - -static affine_fn -affine_fn_cst (tree cst) -{ - affine_fn fn; - fn.create (1); - fn.quick_push (cst); - return fn; -} - -/* Returns affine function with single variable, CST + COEF * x_DIM. */ - -static affine_fn -affine_fn_univar (tree cst, unsigned dim, tree coef) -{ - affine_fn fn; - fn.create (dim + 1); - unsigned i; - - gcc_assert (dim > 0); - fn.quick_push (cst); - for (i = 1; i < dim; i++) - fn.quick_push (integer_zero_node); - fn.quick_push (coef); - return fn; -} - -/* Analyze a ZIV (Zero Index Variable) subscript. *OVERLAPS_A and - *OVERLAPS_B are initialized to the functions that describe the - relation between the elements accessed twice by CHREC_A and - CHREC_B. For k >= 0, the following property is verified: - - CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */ - -static void -analyze_ziv_subscript (tree chrec_a, - tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts) -{ - tree type, difference; - dependence_stats.num_ziv++; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "(analyze_ziv_subscript \n"); - - type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b)); - chrec_a = chrec_convert (type, chrec_a, NULL); - chrec_b = chrec_convert (type, chrec_b, NULL); - difference = chrec_fold_minus (type, chrec_a, chrec_b); - - switch (TREE_CODE (difference)) - { - case INTEGER_CST: - if (integer_zerop (difference)) - { - /* The difference is equal to zero: the accessed index - overlaps for each iteration in the loop. */ - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = chrec_dont_know; - dependence_stats.num_ziv_dependent++; - } - else - { - /* The accesses do not overlap. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_ziv_independent++; - } - break; - - default: - /* We're not sure whether the indexes overlap. For the moment, - conservatively answer "don't know". */ - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "ziv test failed: difference is non-integer.\n"); - - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - dependence_stats.num_ziv_unimplemented++; - break; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, ")\n"); -} - -/* Similar to max_stmt_executions_int, but returns the bound as a tree, - and only if it fits to the int type. If this is not the case, or the - bound on the number of iterations of LOOP could not be derived, returns - chrec_dont_know. */ - -static tree -max_stmt_executions_tree (class loop *loop) -{ - widest_int nit; - - if (!max_stmt_executions (loop, &nit)) - return chrec_dont_know; - - if (!wi::fits_to_tree_p (nit, unsigned_type_node)) - return chrec_dont_know; - - return wide_int_to_tree (unsigned_type_node, nit); -} - -/* Determine whether the CHREC is always positive/negative. If the expression - cannot be statically analyzed, return false, otherwise set the answer into - VALUE. */ - -static bool -chrec_is_positive (tree chrec, bool *value) -{ - bool value0, value1, value2; - tree end_value, nb_iter; - - switch (TREE_CODE (chrec)) - { - case POLYNOMIAL_CHREC: - if (!chrec_is_positive (CHREC_LEFT (chrec), &value0) - || !chrec_is_positive (CHREC_RIGHT (chrec), &value1)) - return false; - - /* FIXME -- overflows. */ - if (value0 == value1) - { - *value = value0; - return true; - } - - /* Otherwise the chrec is under the form: "{-197, +, 2}_1", - and the proof consists in showing that the sign never - changes during the execution of the loop, from 0 to - loop->nb_iterations. */ - if (!evolution_function_is_affine_p (chrec)) - return false; - - nb_iter = number_of_latch_executions (get_chrec_loop (chrec)); - if (chrec_contains_undetermined (nb_iter)) - return false; - -#if 0 - /* TODO -- If the test is after the exit, we may decrease the number of - iterations by one. */ - if (after_exit) - nb_iter = chrec_fold_minus (type, nb_iter, build_int_cst (type, 1)); -#endif - - end_value = chrec_apply (CHREC_VARIABLE (chrec), chrec, nb_iter); - - if (!chrec_is_positive (end_value, &value2)) - return false; - - *value = value0; - return value0 == value1; - - case INTEGER_CST: - switch (tree_int_cst_sgn (chrec)) - { - case -1: - *value = false; - break; - case 1: - *value = true; - break; - default: - return false; - } - return true; - - default: - return false; - } -} - - -/* Analyze a SIV (Single Index Variable) subscript where CHREC_A is a - constant, and CHREC_B is an affine function. *OVERLAPS_A and - *OVERLAPS_B are initialized to the functions that describe the - relation between the elements accessed twice by CHREC_A and - CHREC_B. For k >= 0, the following property is verified: - - CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */ - -static void -analyze_siv_subscript_cst_affine (tree chrec_a, - tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts) -{ - bool value0, value1, value2; - tree type, difference, tmp; - - type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b)); - chrec_a = chrec_convert (type, chrec_a, NULL); - chrec_b = chrec_convert (type, chrec_b, NULL); - difference = chrec_fold_minus (type, initial_condition (chrec_b), chrec_a); - - /* Special case overlap in the first iteration. */ - if (integer_zerop (difference)) - { - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = integer_one_node; - return; - } - - if (!chrec_is_positive (initial_condition (difference), &value0)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "siv test failed: chrec is not positive.\n"); - - dependence_stats.num_siv_unimplemented++; - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - return; - } - else - { - if (value0 == false) - { - if (TREE_CODE (chrec_b) != POLYNOMIAL_CHREC - || !chrec_is_positive (CHREC_RIGHT (chrec_b), &value1)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "siv test failed: chrec not positive.\n"); - - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - dependence_stats.num_siv_unimplemented++; - return; - } - else - { - if (value1 == true) - { - /* Example: - chrec_a = 12 - chrec_b = {10, +, 1} - */ - - if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference)) - { - HOST_WIDE_INT numiter; - class loop *loop = get_chrec_loop (chrec_b); - - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - tmp = fold_build2 (EXACT_DIV_EXPR, type, - fold_build1 (ABS_EXPR, type, difference), - CHREC_RIGHT (chrec_b)); - *overlaps_b = conflict_fn (1, affine_fn_cst (tmp)); - *last_conflicts = integer_one_node; - - - /* Perform weak-zero siv test to see if overlap is - outside the loop bounds. */ - numiter = max_stmt_executions_int (loop); - - if (numiter >= 0 - && compare_tree_int (tmp, numiter) > 0) - { - free_conflict_function (*overlaps_a); - free_conflict_function (*overlaps_b); - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - dependence_stats.num_siv_dependent++; - return; - } - - /* When the step does not divide the difference, there are - no overlaps. */ - else - { - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - } - - else - { - /* Example: - chrec_a = 12 - chrec_b = {10, +, -1} - - In this case, chrec_a will not overlap with chrec_b. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - } - } - else - { - if (TREE_CODE (chrec_b) != POLYNOMIAL_CHREC - || !chrec_is_positive (CHREC_RIGHT (chrec_b), &value2)) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "siv test failed: chrec not positive.\n"); - - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - dependence_stats.num_siv_unimplemented++; - return; - } - else - { - if (value2 == false) - { - /* Example: - chrec_a = 3 - chrec_b = {10, +, -1} - */ - if (tree_fold_divides_p (CHREC_RIGHT (chrec_b), difference)) - { - HOST_WIDE_INT numiter; - class loop *loop = get_chrec_loop (chrec_b); - - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - tmp = fold_build2 (EXACT_DIV_EXPR, type, difference, - CHREC_RIGHT (chrec_b)); - *overlaps_b = conflict_fn (1, affine_fn_cst (tmp)); - *last_conflicts = integer_one_node; - - /* Perform weak-zero siv test to see if overlap is - outside the loop bounds. */ - numiter = max_stmt_executions_int (loop); - - if (numiter >= 0 - && compare_tree_int (tmp, numiter) > 0) - { - free_conflict_function (*overlaps_a); - free_conflict_function (*overlaps_b); - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - dependence_stats.num_siv_dependent++; - return; - } - - /* When the step does not divide the difference, there - are no overlaps. */ - else - { - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - } - else - { - /* Example: - chrec_a = 3 - chrec_b = {4, +, 1} - - In this case, chrec_a will not overlap with chrec_b. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_siv_independent++; - return; - } - } - } - } -} - -/* Helper recursive function for initializing the matrix A. Returns - the initial value of CHREC. */ - -static tree -initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult) -{ - gcc_assert (chrec); - - switch (TREE_CODE (chrec)) - { - case POLYNOMIAL_CHREC: - HOST_WIDE_INT chrec_right; - if (!cst_and_fits_in_hwi (CHREC_RIGHT (chrec))) - return chrec_dont_know; - chrec_right = int_cst_value (CHREC_RIGHT (chrec)); - /* We want to be able to negate without overflow. */ - if (chrec_right == HOST_WIDE_INT_MIN) - return chrec_dont_know; - A[index][0] = mult * chrec_right; - return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult); - - case PLUS_EXPR: - case MULT_EXPR: - case MINUS_EXPR: - { - tree op0 = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult); - tree op1 = initialize_matrix_A (A, TREE_OPERAND (chrec, 1), index, mult); - - return chrec_fold_op (TREE_CODE (chrec), chrec_type (chrec), op0, op1); - } - - CASE_CONVERT: - { - tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult); - return chrec_convert (chrec_type (chrec), op, NULL); - } - - case BIT_NOT_EXPR: - { - /* Handle ~X as -1 - X. */ - tree op = initialize_matrix_A (A, TREE_OPERAND (chrec, 0), index, mult); - return chrec_fold_op (MINUS_EXPR, chrec_type (chrec), - build_int_cst (TREE_TYPE (chrec), -1), op); - } - - case INTEGER_CST: - return chrec; - - default: - gcc_unreachable (); - return NULL_TREE; - } -} - -#define FLOOR_DIV(x,y) ((x) / (y)) - -/* Solves the special case of the Diophantine equation: - | {0, +, STEP_A}_x (OVERLAPS_A) = {0, +, STEP_B}_y (OVERLAPS_B) - - Computes the descriptions OVERLAPS_A and OVERLAPS_B. NITER is the - number of iterations that loops X and Y run. The overlaps will be - constructed as evolutions in dimension DIM. */ - -static void -compute_overlap_steps_for_affine_univar (HOST_WIDE_INT niter, - HOST_WIDE_INT step_a, - HOST_WIDE_INT step_b, - affine_fn *overlaps_a, - affine_fn *overlaps_b, - tree *last_conflicts, int dim) -{ - if (((step_a > 0 && step_b > 0) - || (step_a < 0 && step_b < 0))) - { - HOST_WIDE_INT step_overlaps_a, step_overlaps_b; - HOST_WIDE_INT gcd_steps_a_b, last_conflict, tau2; - - gcd_steps_a_b = gcd (step_a, step_b); - step_overlaps_a = step_b / gcd_steps_a_b; - step_overlaps_b = step_a / gcd_steps_a_b; - - if (niter > 0) - { - tau2 = FLOOR_DIV (niter, step_overlaps_a); - tau2 = MIN (tau2, FLOOR_DIV (niter, step_overlaps_b)); - last_conflict = tau2; - *last_conflicts = build_int_cst (NULL_TREE, last_conflict); - } - else - *last_conflicts = chrec_dont_know; - - *overlaps_a = affine_fn_univar (integer_zero_node, dim, - build_int_cst (NULL_TREE, - step_overlaps_a)); - *overlaps_b = affine_fn_univar (integer_zero_node, dim, - build_int_cst (NULL_TREE, - step_overlaps_b)); - } - - else - { - *overlaps_a = affine_fn_cst (integer_zero_node); - *overlaps_b = affine_fn_cst (integer_zero_node); - *last_conflicts = integer_zero_node; - } -} - -/* Solves the special case of a Diophantine equation where CHREC_A is - an affine bivariate function, and CHREC_B is an affine univariate - function. For example, - - | {{0, +, 1}_x, +, 1335}_y = {0, +, 1336}_z - - has the following overlapping functions: - - | x (t, u, v) = {{0, +, 1336}_t, +, 1}_v - | y (t, u, v) = {{0, +, 1336}_u, +, 1}_v - | z (t, u, v) = {{{0, +, 1}_t, +, 1335}_u, +, 1}_v - - FORNOW: This is a specialized implementation for a case occurring in - a common benchmark. Implement the general algorithm. */ - -static void -compute_overlap_steps_for_affine_1_2 (tree chrec_a, tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts) -{ - bool xz_p, yz_p, xyz_p; - HOST_WIDE_INT step_x, step_y, step_z; - HOST_WIDE_INT niter_x, niter_y, niter_z, niter; - affine_fn overlaps_a_xz, overlaps_b_xz; - affine_fn overlaps_a_yz, overlaps_b_yz; - affine_fn overlaps_a_xyz, overlaps_b_xyz; - affine_fn ova1, ova2, ovb; - tree last_conflicts_xz, last_conflicts_yz, last_conflicts_xyz; - - step_x = int_cst_value (CHREC_RIGHT (CHREC_LEFT (chrec_a))); - step_y = int_cst_value (CHREC_RIGHT (chrec_a)); - step_z = int_cst_value (CHREC_RIGHT (chrec_b)); - - niter_x = max_stmt_executions_int (get_chrec_loop (CHREC_LEFT (chrec_a))); - niter_y = max_stmt_executions_int (get_chrec_loop (chrec_a)); - niter_z = max_stmt_executions_int (get_chrec_loop (chrec_b)); - - if (niter_x < 0 || niter_y < 0 || niter_z < 0) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "overlap steps test failed: no iteration counts.\n"); - - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - return; - } - - niter = MIN (niter_x, niter_z); - compute_overlap_steps_for_affine_univar (niter, step_x, step_z, - &overlaps_a_xz, - &overlaps_b_xz, - &last_conflicts_xz, 1); - niter = MIN (niter_y, niter_z); - compute_overlap_steps_for_affine_univar (niter, step_y, step_z, - &overlaps_a_yz, - &overlaps_b_yz, - &last_conflicts_yz, 2); - niter = MIN (niter_x, niter_z); - niter = MIN (niter_y, niter); - compute_overlap_steps_for_affine_univar (niter, step_x + step_y, step_z, - &overlaps_a_xyz, - &overlaps_b_xyz, - &last_conflicts_xyz, 3); - - xz_p = !integer_zerop (last_conflicts_xz); - yz_p = !integer_zerop (last_conflicts_yz); - xyz_p = !integer_zerop (last_conflicts_xyz); - - if (xz_p || yz_p || xyz_p) - { - ova1 = affine_fn_cst (integer_zero_node); - ova2 = affine_fn_cst (integer_zero_node); - ovb = affine_fn_cst (integer_zero_node); - if (xz_p) - { - affine_fn t0 = ova1; - affine_fn t2 = ovb; - - ova1 = affine_fn_plus (ova1, overlaps_a_xz); - ovb = affine_fn_plus (ovb, overlaps_b_xz); - affine_fn_free (t0); - affine_fn_free (t2); - *last_conflicts = last_conflicts_xz; - } - if (yz_p) - { - affine_fn t0 = ova2; - affine_fn t2 = ovb; - - ova2 = affine_fn_plus (ova2, overlaps_a_yz); - ovb = affine_fn_plus (ovb, overlaps_b_yz); - affine_fn_free (t0); - affine_fn_free (t2); - *last_conflicts = last_conflicts_yz; - } - if (xyz_p) - { - affine_fn t0 = ova1; - affine_fn t2 = ova2; - affine_fn t4 = ovb; - - ova1 = affine_fn_plus (ova1, overlaps_a_xyz); - ova2 = affine_fn_plus (ova2, overlaps_a_xyz); - ovb = affine_fn_plus (ovb, overlaps_b_xyz); - affine_fn_free (t0); - affine_fn_free (t2); - affine_fn_free (t4); - *last_conflicts = last_conflicts_xyz; - } - *overlaps_a = conflict_fn (2, ova1, ova2); - *overlaps_b = conflict_fn (1, ovb); - } - else - { - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = integer_zero_node; - } - - affine_fn_free (overlaps_a_xz); - affine_fn_free (overlaps_b_xz); - affine_fn_free (overlaps_a_yz); - affine_fn_free (overlaps_b_yz); - affine_fn_free (overlaps_a_xyz); - affine_fn_free (overlaps_b_xyz); -} - -/* Copy the elements of vector VEC1 with length SIZE to VEC2. */ - -static void -lambda_vector_copy (lambda_vector vec1, lambda_vector vec2, - int size) -{ - memcpy (vec2, vec1, size * sizeof (*vec1)); -} - -/* Copy the elements of M x N matrix MAT1 to MAT2. */ - -static void -lambda_matrix_copy (lambda_matrix mat1, lambda_matrix mat2, - int m, int n) -{ - int i; - - for (i = 0; i < m; i++) - lambda_vector_copy (mat1[i], mat2[i], n); -} - -/* Store the N x N identity matrix in MAT. */ - -static void -lambda_matrix_id (lambda_matrix mat, int size) -{ - int i, j; - - for (i = 0; i < size; i++) - for (j = 0; j < size; j++) - mat[i][j] = (i == j) ? 1 : 0; -} - -/* Return the index of the first nonzero element of vector VEC1 between - START and N. We must have START <= N. - Returns N if VEC1 is the zero vector. */ - -static int -lambda_vector_first_nz (lambda_vector vec1, int n, int start) -{ - int j = start; - while (j < n && vec1[j] == 0) - j++; - return j; -} - -/* Add a multiple of row R1 of matrix MAT with N columns to row R2: - R2 = R2 + CONST1 * R1. */ - -static bool -lambda_matrix_row_add (lambda_matrix mat, int n, int r1, int r2, - lambda_int const1) -{ - int i; - - if (const1 == 0) - return true; - - for (i = 0; i < n; i++) - { - bool ovf; - lambda_int tem = mul_hwi (mat[r1][i], const1, &ovf); - if (ovf) - return false; - lambda_int tem2 = add_hwi (mat[r2][i], tem, &ovf); - if (ovf || tem2 == HOST_WIDE_INT_MIN) - return false; - mat[r2][i] = tem2; - } - - return true; -} - -/* Multiply vector VEC1 of length SIZE by a constant CONST1, - and store the result in VEC2. */ - -static void -lambda_vector_mult_const (lambda_vector vec1, lambda_vector vec2, - int size, lambda_int const1) -{ - int i; - - if (const1 == 0) - lambda_vector_clear (vec2, size); - else - for (i = 0; i < size; i++) - vec2[i] = const1 * vec1[i]; -} - -/* Negate vector VEC1 with length SIZE and store it in VEC2. */ - -static void -lambda_vector_negate (lambda_vector vec1, lambda_vector vec2, - int size) -{ - lambda_vector_mult_const (vec1, vec2, size, -1); -} - -/* Negate row R1 of matrix MAT which has N columns. */ - -static void -lambda_matrix_row_negate (lambda_matrix mat, int n, int r1) -{ - lambda_vector_negate (mat[r1], mat[r1], n); -} - -/* Return true if two vectors are equal. */ - -static bool -lambda_vector_equal (lambda_vector vec1, lambda_vector vec2, int size) -{ - int i; - for (i = 0; i < size; i++) - if (vec1[i] != vec2[i]) - return false; - return true; -} - -/* Given an M x N integer matrix A, this function determines an M x - M unimodular matrix U, and an M x N echelon matrix S such that - "U.A = S". This decomposition is also known as "right Hermite". - - Ref: Algorithm 2.1 page 33 in "Loop Transformations for - Restructuring Compilers" Utpal Banerjee. */ - -static bool -lambda_matrix_right_hermite (lambda_matrix A, int m, int n, - lambda_matrix S, lambda_matrix U) -{ - int i, j, i0 = 0; - - lambda_matrix_copy (A, S, m, n); - lambda_matrix_id (U, m); - - for (j = 0; j < n; j++) - { - if (lambda_vector_first_nz (S[j], m, i0) < m) - { - ++i0; - for (i = m - 1; i >= i0; i--) - { - while (S[i][j] != 0) - { - lambda_int factor, a, b; - - a = S[i-1][j]; - b = S[i][j]; - gcc_assert (a != HOST_WIDE_INT_MIN); - factor = a / b; - - if (!lambda_matrix_row_add (S, n, i, i-1, -factor)) - return false; - std::swap (S[i], S[i-1]); - - if (!lambda_matrix_row_add (U, m, i, i-1, -factor)) - return false; - std::swap (U[i], U[i-1]); - } - } - } - } - - return true; -} - -/* Determines the overlapping elements due to accesses CHREC_A and - CHREC_B, that are affine functions. This function cannot handle - symbolic evolution functions, ie. when initial conditions are - parameters, because it uses lambda matrices of integers. */ - -static void -analyze_subscript_affine_affine (tree chrec_a, - tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts) -{ - unsigned nb_vars_a, nb_vars_b, dim; - lambda_int gamma, gcd_alpha_beta; - lambda_matrix A, U, S; - struct obstack scratch_obstack; - - if (eq_evolutions_p (chrec_a, chrec_b)) - { - /* The accessed index overlaps for each iteration in the - loop. */ - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = chrec_dont_know; - return; - } - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "(analyze_subscript_affine_affine \n"); - - /* For determining the initial intersection, we have to solve a - Diophantine equation. This is the most time consuming part. - - For answering to the question: "Is there a dependence?" we have - to prove that there exists a solution to the Diophantine - equation, and that the solution is in the iteration domain, - i.e. the solution is positive or zero, and that the solution - happens before the upper bound loop.nb_iterations. Otherwise - there is no dependence. This function outputs a description of - the iterations that hold the intersections. */ - - nb_vars_a = nb_vars_in_chrec (chrec_a); - nb_vars_b = nb_vars_in_chrec (chrec_b); - - gcc_obstack_init (&scratch_obstack); - - dim = nb_vars_a + nb_vars_b; - U = lambda_matrix_new (dim, dim, &scratch_obstack); - A = lambda_matrix_new (dim, 1, &scratch_obstack); - S = lambda_matrix_new (dim, 1, &scratch_obstack); - - tree init_a = initialize_matrix_A (A, chrec_a, 0, 1); - tree init_b = initialize_matrix_A (A, chrec_b, nb_vars_a, -1); - if (init_a == chrec_dont_know - || init_b == chrec_dont_know) - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "affine-affine test failed: " - "representation issue.\n"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - goto end_analyze_subs_aa; - } - gamma = int_cst_value (init_b) - int_cst_value (init_a); - - /* Don't do all the hard work of solving the Diophantine equation - when we already know the solution: for example, - | {3, +, 1}_1 - | {3, +, 4}_2 - | gamma = 3 - 3 = 0. - Then the first overlap occurs during the first iterations: - | {3, +, 1}_1 ({0, +, 4}_x) = {3, +, 4}_2 ({0, +, 1}_x) - */ - if (gamma == 0) - { - if (nb_vars_a == 1 && nb_vars_b == 1) - { - HOST_WIDE_INT step_a, step_b; - HOST_WIDE_INT niter, niter_a, niter_b; - affine_fn ova, ovb; - - niter_a = max_stmt_executions_int (get_chrec_loop (chrec_a)); - niter_b = max_stmt_executions_int (get_chrec_loop (chrec_b)); - niter = MIN (niter_a, niter_b); - step_a = int_cst_value (CHREC_RIGHT (chrec_a)); - step_b = int_cst_value (CHREC_RIGHT (chrec_b)); - - compute_overlap_steps_for_affine_univar (niter, step_a, step_b, - &ova, &ovb, - last_conflicts, 1); - *overlaps_a = conflict_fn (1, ova); - *overlaps_b = conflict_fn (1, ovb); - } - - else if (nb_vars_a == 2 && nb_vars_b == 1) - compute_overlap_steps_for_affine_1_2 - (chrec_a, chrec_b, overlaps_a, overlaps_b, last_conflicts); - - else if (nb_vars_a == 1 && nb_vars_b == 2) - compute_overlap_steps_for_affine_1_2 - (chrec_b, chrec_a, overlaps_b, overlaps_a, last_conflicts); - - else - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "affine-affine test failed: too many variables.\n"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - } - goto end_analyze_subs_aa; - } - - /* U.A = S */ - if (!lambda_matrix_right_hermite (A, dim, 1, S, U)) - { - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - goto end_analyze_subs_aa; - } - - if (S[0][0] < 0) - { - S[0][0] *= -1; - lambda_matrix_row_negate (U, dim, 0); - } - gcd_alpha_beta = S[0][0]; - - /* Something went wrong: for example in {1, +, 0}_5 vs. {0, +, 0}_5, - but that is a quite strange case. Instead of ICEing, answer - don't know. */ - if (gcd_alpha_beta == 0) - { - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - goto end_analyze_subs_aa; - } - - /* The classic "gcd-test". */ - if (!int_divides_p (gcd_alpha_beta, gamma)) - { - /* The "gcd-test" has determined that there is no integer - solution, i.e. there is no dependence. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - } - - /* Both access functions are univariate. This includes SIV and MIV cases. */ - else if (nb_vars_a == 1 && nb_vars_b == 1) - { - /* Both functions should have the same evolution sign. */ - if (((A[0][0] > 0 && -A[1][0] > 0) - || (A[0][0] < 0 && -A[1][0] < 0))) - { - /* The solutions are given by: - | - | [GAMMA/GCD_ALPHA_BETA t].[u11 u12] = [x0] - | [u21 u22] [y0] - - For a given integer t. Using the following variables, - - | i0 = u11 * gamma / gcd_alpha_beta - | j0 = u12 * gamma / gcd_alpha_beta - | i1 = u21 - | j1 = u22 - - the solutions are: - - | x0 = i0 + i1 * t, - | y0 = j0 + j1 * t. */ - HOST_WIDE_INT i0, j0, i1, j1; - - i0 = U[0][0] * gamma / gcd_alpha_beta; - j0 = U[0][1] * gamma / gcd_alpha_beta; - i1 = U[1][0]; - j1 = U[1][1]; - - if ((i1 == 0 && i0 < 0) - || (j1 == 0 && j0 < 0)) - { - /* There is no solution. - FIXME: The case "i0 > nb_iterations, j0 > nb_iterations" - falls in here, but for the moment we don't look at the - upper bound of the iteration domain. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - goto end_analyze_subs_aa; - } - - if (i1 > 0 && j1 > 0) - { - HOST_WIDE_INT niter_a - = max_stmt_executions_int (get_chrec_loop (chrec_a)); - HOST_WIDE_INT niter_b - = max_stmt_executions_int (get_chrec_loop (chrec_b)); - HOST_WIDE_INT niter = MIN (niter_a, niter_b); - - /* (X0, Y0) is a solution of the Diophantine equation: - "chrec_a (X0) = chrec_b (Y0)". */ - HOST_WIDE_INT tau1 = MAX (CEIL (-i0, i1), - CEIL (-j0, j1)); - HOST_WIDE_INT x0 = i1 * tau1 + i0; - HOST_WIDE_INT y0 = j1 * tau1 + j0; - - /* (X1, Y1) is the smallest positive solution of the eq - "chrec_a (X1) = chrec_b (Y1)", i.e. this is where the - first conflict occurs. */ - HOST_WIDE_INT min_multiple = MIN (x0 / i1, y0 / j1); - HOST_WIDE_INT x1 = x0 - i1 * min_multiple; - HOST_WIDE_INT y1 = y0 - j1 * min_multiple; - - if (niter > 0) - { - /* If the overlap occurs outside of the bounds of the - loop, there is no dependence. */ - if (x1 >= niter_a || y1 >= niter_b) - { - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - goto end_analyze_subs_aa; - } - - /* max stmt executions can get quite large, avoid - overflows by using wide ints here. */ - widest_int tau2 - = wi::smin (wi::sdiv_floor (wi::sub (niter_a, i0), i1), - wi::sdiv_floor (wi::sub (niter_b, j0), j1)); - widest_int last_conflict = wi::sub (tau2, (x1 - i0)/i1); - if (wi::min_precision (last_conflict, SIGNED) - <= TYPE_PRECISION (integer_type_node)) - *last_conflicts - = build_int_cst (integer_type_node, - last_conflict.to_shwi ()); - else - *last_conflicts = chrec_dont_know; - } - else - *last_conflicts = chrec_dont_know; - - *overlaps_a - = conflict_fn (1, - affine_fn_univar (build_int_cst (NULL_TREE, x1), - 1, - build_int_cst (NULL_TREE, i1))); - *overlaps_b - = conflict_fn (1, - affine_fn_univar (build_int_cst (NULL_TREE, y1), - 1, - build_int_cst (NULL_TREE, j1))); - } - else - { - /* FIXME: For the moment, the upper bound of the - iteration domain for i and j is not checked. */ - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - } - } - else - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - } - } - else - { - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - } - -end_analyze_subs_aa: - obstack_free (&scratch_obstack, NULL); - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " (overlaps_a = "); - dump_conflict_function (dump_file, *overlaps_a); - fprintf (dump_file, ")\n (overlaps_b = "); - dump_conflict_function (dump_file, *overlaps_b); - fprintf (dump_file, "))\n"); - } -} - -/* Returns true when analyze_subscript_affine_affine can be used for - determining the dependence relation between chrec_a and chrec_b, - that contain symbols. This function modifies chrec_a and chrec_b - such that the analysis result is the same, and such that they don't - contain symbols, and then can safely be passed to the analyzer. - - Example: The analysis of the following tuples of evolutions produce - the same results: {x+1, +, 1}_1 vs. {x+3, +, 1}_1, and {-2, +, 1}_1 - vs. {0, +, 1}_1 - - {x+1, +, 1}_1 ({2, +, 1}_1) = {x+3, +, 1}_1 ({0, +, 1}_1) - {-2, +, 1}_1 ({2, +, 1}_1) = {0, +, 1}_1 ({0, +, 1}_1) -*/ - -static bool -can_use_analyze_subscript_affine_affine (tree *chrec_a, tree *chrec_b) -{ - tree diff, type, left_a, left_b, right_b; - - if (chrec_contains_symbols (CHREC_RIGHT (*chrec_a)) - || chrec_contains_symbols (CHREC_RIGHT (*chrec_b))) - /* FIXME: For the moment not handled. Might be refined later. */ - return false; - - type = chrec_type (*chrec_a); - left_a = CHREC_LEFT (*chrec_a); - left_b = chrec_convert (type, CHREC_LEFT (*chrec_b), NULL); - diff = chrec_fold_minus (type, left_a, left_b); - - if (!evolution_function_is_constant_p (diff)) - return false; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "can_use_subscript_aff_aff_for_symbolic \n"); - - *chrec_a = build_polynomial_chrec (CHREC_VARIABLE (*chrec_a), - diff, CHREC_RIGHT (*chrec_a)); - right_b = chrec_convert (type, CHREC_RIGHT (*chrec_b), NULL); - *chrec_b = build_polynomial_chrec (CHREC_VARIABLE (*chrec_b), - build_int_cst (type, 0), - right_b); - return true; -} - -/* Analyze a SIV (Single Index Variable) subscript. *OVERLAPS_A and - *OVERLAPS_B are initialized to the functions that describe the - relation between the elements accessed twice by CHREC_A and - CHREC_B. For k >= 0, the following property is verified: - - CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */ - -static void -analyze_siv_subscript (tree chrec_a, - tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts, - int loop_nest_num) -{ - dependence_stats.num_siv++; - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "(analyze_siv_subscript \n"); - - if (evolution_function_is_constant_p (chrec_a) - && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num)) - analyze_siv_subscript_cst_affine (chrec_a, chrec_b, - overlaps_a, overlaps_b, last_conflicts); - - else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num) - && evolution_function_is_constant_p (chrec_b)) - analyze_siv_subscript_cst_affine (chrec_b, chrec_a, - overlaps_b, overlaps_a, last_conflicts); - - else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest_num) - && evolution_function_is_affine_in_loop (chrec_b, loop_nest_num)) - { - if (!chrec_contains_symbols (chrec_a) - && !chrec_contains_symbols (chrec_b)) - { - analyze_subscript_affine_affine (chrec_a, chrec_b, - overlaps_a, overlaps_b, - last_conflicts); - - if (CF_NOT_KNOWN_P (*overlaps_a) - || CF_NOT_KNOWN_P (*overlaps_b)) - dependence_stats.num_siv_unimplemented++; - else if (CF_NO_DEPENDENCE_P (*overlaps_a) - || CF_NO_DEPENDENCE_P (*overlaps_b)) - dependence_stats.num_siv_independent++; - else - dependence_stats.num_siv_dependent++; - } - else if (can_use_analyze_subscript_affine_affine (&chrec_a, - &chrec_b)) - { - analyze_subscript_affine_affine (chrec_a, chrec_b, - overlaps_a, overlaps_b, - last_conflicts); - - if (CF_NOT_KNOWN_P (*overlaps_a) - || CF_NOT_KNOWN_P (*overlaps_b)) - dependence_stats.num_siv_unimplemented++; - else if (CF_NO_DEPENDENCE_P (*overlaps_a) - || CF_NO_DEPENDENCE_P (*overlaps_b)) - dependence_stats.num_siv_independent++; - else - dependence_stats.num_siv_dependent++; - } - else - goto siv_subscript_dontknow; - } - - else - { - siv_subscript_dontknow:; - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, " siv test failed: unimplemented"); - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - dependence_stats.num_siv_unimplemented++; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, ")\n"); -} - -/* Returns false if we can prove that the greatest common divisor of the steps - of CHREC does not divide CST, false otherwise. */ - -static bool -gcd_of_steps_may_divide_p (const_tree chrec, const_tree cst) -{ - HOST_WIDE_INT cd = 0, val; - tree step; - - if (!tree_fits_shwi_p (cst)) - return true; - val = tree_to_shwi (cst); - - while (TREE_CODE (chrec) == POLYNOMIAL_CHREC) - { - step = CHREC_RIGHT (chrec); - if (!tree_fits_shwi_p (step)) - return true; - cd = gcd (cd, tree_to_shwi (step)); - chrec = CHREC_LEFT (chrec); - } - - return val % cd == 0; -} - -/* Analyze a MIV (Multiple Index Variable) subscript with respect to - LOOP_NEST. *OVERLAPS_A and *OVERLAPS_B are initialized to the - functions that describe the relation between the elements accessed - twice by CHREC_A and CHREC_B. For k >= 0, the following property - is verified: - - CHREC_A (*OVERLAPS_A (k)) = CHREC_B (*OVERLAPS_B (k)). */ - -static void -analyze_miv_subscript (tree chrec_a, - tree chrec_b, - conflict_function **overlaps_a, - conflict_function **overlaps_b, - tree *last_conflicts, - class loop *loop_nest) -{ - tree type, difference; - - dependence_stats.num_miv++; - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "(analyze_miv_subscript \n"); - - type = signed_type_for_types (TREE_TYPE (chrec_a), TREE_TYPE (chrec_b)); - chrec_a = chrec_convert (type, chrec_a, NULL); - chrec_b = chrec_convert (type, chrec_b, NULL); - difference = chrec_fold_minus (type, chrec_a, chrec_b); - - if (eq_evolutions_p (chrec_a, chrec_b)) - { - /* Access functions are the same: all the elements are accessed - in the same order. */ - *overlaps_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlaps_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = max_stmt_executions_tree (get_chrec_loop (chrec_a)); - dependence_stats.num_miv_dependent++; - } - - else if (evolution_function_is_constant_p (difference) - && evolution_function_is_affine_multivariate_p (chrec_a, - loop_nest->num) - && !gcd_of_steps_may_divide_p (chrec_a, difference)) - { - /* testsuite/.../ssa-chrec-33.c - {{21, +, 2}_1, +, -2}_2 vs. {{20, +, 2}_1, +, -2}_2 - - The difference is 1, and all the evolution steps are multiples - of 2, consequently there are no overlapping elements. */ - *overlaps_a = conflict_fn_no_dependence (); - *overlaps_b = conflict_fn_no_dependence (); - *last_conflicts = integer_zero_node; - dependence_stats.num_miv_independent++; - } - - else if (evolution_function_is_affine_in_loop (chrec_a, loop_nest->num) - && !chrec_contains_symbols (chrec_a, loop_nest) - && evolution_function_is_affine_in_loop (chrec_b, loop_nest->num) - && !chrec_contains_symbols (chrec_b, loop_nest)) - { - /* testsuite/.../ssa-chrec-35.c - {0, +, 1}_2 vs. {0, +, 1}_3 - the overlapping elements are respectively located at iterations: - {0, +, 1}_x and {0, +, 1}_x, - in other words, we have the equality: - {0, +, 1}_2 ({0, +, 1}_x) = {0, +, 1}_3 ({0, +, 1}_x) - - Other examples: - {{0, +, 1}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y) = - {0, +, 1}_1 ({{0, +, 1}_x, +, 2}_y) - - {{0, +, 2}_1, +, 3}_2 ({0, +, 1}_y, {0, +, 1}_x) = - {{0, +, 3}_1, +, 2}_2 ({0, +, 1}_x, {0, +, 1}_y) - */ - analyze_subscript_affine_affine (chrec_a, chrec_b, - overlaps_a, overlaps_b, last_conflicts); - - if (CF_NOT_KNOWN_P (*overlaps_a) - || CF_NOT_KNOWN_P (*overlaps_b)) - dependence_stats.num_miv_unimplemented++; - else if (CF_NO_DEPENDENCE_P (*overlaps_a) - || CF_NO_DEPENDENCE_P (*overlaps_b)) - dependence_stats.num_miv_independent++; - else - dependence_stats.num_miv_dependent++; - } - - else - { - /* When the analysis is too difficult, answer "don't know". */ - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, "analyze_miv_subscript test failed: unimplemented.\n"); - - *overlaps_a = conflict_fn_not_known (); - *overlaps_b = conflict_fn_not_known (); - *last_conflicts = chrec_dont_know; - dependence_stats.num_miv_unimplemented++; - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - fprintf (dump_file, ")\n"); -} - -/* Determines the iterations for which CHREC_A is equal to CHREC_B in - with respect to LOOP_NEST. OVERLAP_ITERATIONS_A and - OVERLAP_ITERATIONS_B are initialized with two functions that - describe the iterations that contain conflicting elements. - - Remark: For an integer k >= 0, the following equality is true: - - CHREC_A (OVERLAP_ITERATIONS_A (k)) == CHREC_B (OVERLAP_ITERATIONS_B (k)). -*/ - -static void -analyze_overlapping_iterations (tree chrec_a, - tree chrec_b, - conflict_function **overlap_iterations_a, - conflict_function **overlap_iterations_b, - tree *last_conflicts, class loop *loop_nest) -{ - unsigned int lnn = loop_nest->num; - - dependence_stats.num_subscript_tests++; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "(analyze_overlapping_iterations \n"); - fprintf (dump_file, " (chrec_a = "); - print_generic_expr (dump_file, chrec_a); - fprintf (dump_file, ")\n (chrec_b = "); - print_generic_expr (dump_file, chrec_b); - fprintf (dump_file, ")\n"); - } - - if (chrec_a == NULL_TREE - || chrec_b == NULL_TREE - || chrec_contains_undetermined (chrec_a) - || chrec_contains_undetermined (chrec_b)) - { - dependence_stats.num_subscript_undetermined++; - - *overlap_iterations_a = conflict_fn_not_known (); - *overlap_iterations_b = conflict_fn_not_known (); - } - - /* If they are the same chrec, and are affine, they overlap - on every iteration. */ - else if (eq_evolutions_p (chrec_a, chrec_b) - && (evolution_function_is_affine_multivariate_p (chrec_a, lnn) - || operand_equal_p (chrec_a, chrec_b, 0))) - { - dependence_stats.num_same_subscript_function++; - *overlap_iterations_a = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *overlap_iterations_b = conflict_fn (1, affine_fn_cst (integer_zero_node)); - *last_conflicts = chrec_dont_know; - } - - /* If they aren't the same, and aren't affine, we can't do anything - yet. */ - else if ((chrec_contains_symbols (chrec_a) - || chrec_contains_symbols (chrec_b)) - && (!evolution_function_is_affine_multivariate_p (chrec_a, lnn) - || !evolution_function_is_affine_multivariate_p (chrec_b, lnn))) - { - dependence_stats.num_subscript_undetermined++; - *overlap_iterations_a = conflict_fn_not_known (); - *overlap_iterations_b = conflict_fn_not_known (); - } - - else if (ziv_subscript_p (chrec_a, chrec_b)) - analyze_ziv_subscript (chrec_a, chrec_b, - overlap_iterations_a, overlap_iterations_b, - last_conflicts); - - else if (siv_subscript_p (chrec_a, chrec_b)) - analyze_siv_subscript (chrec_a, chrec_b, - overlap_iterations_a, overlap_iterations_b, - last_conflicts, lnn); - - else - analyze_miv_subscript (chrec_a, chrec_b, - overlap_iterations_a, overlap_iterations_b, - last_conflicts, loop_nest); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, " (overlap_iterations_a = "); - dump_conflict_function (dump_file, *overlap_iterations_a); - fprintf (dump_file, ")\n (overlap_iterations_b = "); - dump_conflict_function (dump_file, *overlap_iterations_b); - fprintf (dump_file, "))\n"); - } -} - -/* Helper function for uniquely inserting distance vectors. */ - -static void -save_dist_v (struct data_dependence_relation *ddr, lambda_vector dist_v) -{ - for (lambda_vector v : DDR_DIST_VECTS (ddr)) - if (lambda_vector_equal (v, dist_v, DDR_NB_LOOPS (ddr))) - return; - - DDR_DIST_VECTS (ddr).safe_push (dist_v); -} - -/* Helper function for uniquely inserting direction vectors. */ - -static void -save_dir_v (struct data_dependence_relation *ddr, lambda_vector dir_v) -{ - for (lambda_vector v : DDR_DIR_VECTS (ddr)) - if (lambda_vector_equal (v, dir_v, DDR_NB_LOOPS (ddr))) - return; - - DDR_DIR_VECTS (ddr).safe_push (dir_v); -} - -/* Add a distance of 1 on all the loops outer than INDEX. If we - haven't yet determined a distance for this outer loop, push a new - distance vector composed of the previous distance, and a distance - of 1 for this outer loop. Example: - - | loop_1 - | loop_2 - | A[10] - | endloop_2 - | endloop_1 - - Saved vectors are of the form (dist_in_1, dist_in_2). First, we - save (0, 1), then we have to save (1, 0). */ - -static void -add_outer_distances (struct data_dependence_relation *ddr, - lambda_vector dist_v, int index) -{ - /* For each outer loop where init_v is not set, the accesses are - in dependence of distance 1 in the loop. */ - while (--index >= 0) - { - lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr)); - save_v[index] = 1; - save_dist_v (ddr, save_v); - } -} - -/* Return false when fail to represent the data dependence as a - distance vector. A_INDEX is the index of the first reference - (0 for DDR_A, 1 for DDR_B) and B_INDEX is the index of the - second reference. INIT_B is set to true when a component has been - added to the distance vector DIST_V. INDEX_CARRY is then set to - the index in DIST_V that carries the dependence. */ - -static bool -build_classic_dist_vector_1 (struct data_dependence_relation *ddr, - unsigned int a_index, unsigned int b_index, - lambda_vector dist_v, bool *init_b, - int *index_carry) -{ - unsigned i; - lambda_vector init_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - class loop *loop = DDR_LOOP_NEST (ddr)[0]; - - for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) - { - tree access_fn_a, access_fn_b; - struct subscript *subscript = DDR_SUBSCRIPT (ddr, i); - - if (chrec_contains_undetermined (SUB_DISTANCE (subscript))) - { - non_affine_dependence_relation (ddr); - return false; - } - - access_fn_a = SUB_ACCESS_FN (subscript, a_index); - access_fn_b = SUB_ACCESS_FN (subscript, b_index); - - if (TREE_CODE (access_fn_a) == POLYNOMIAL_CHREC - && TREE_CODE (access_fn_b) == POLYNOMIAL_CHREC) - { - HOST_WIDE_INT dist; - int index; - int var_a = CHREC_VARIABLE (access_fn_a); - int var_b = CHREC_VARIABLE (access_fn_b); - - if (var_a != var_b - || chrec_contains_undetermined (SUB_DISTANCE (subscript))) - { - non_affine_dependence_relation (ddr); - return false; - } - - /* When data references are collected in a loop while data - dependences are analyzed in loop nest nested in the loop, we - would have more number of access functions than number of - loops. Skip access functions of loops not in the loop nest. - - See PR89725 for more information. */ - if (flow_loop_nested_p (get_loop (cfun, var_a), loop)) - continue; - - dist = int_cst_value (SUB_DISTANCE (subscript)); - index = index_in_loop_nest (var_a, DDR_LOOP_NEST (ddr)); - *index_carry = MIN (index, *index_carry); - - /* This is the subscript coupling test. If we have already - recorded a distance for this loop (a distance coming from - another subscript), it should be the same. For example, - in the following code, there is no dependence: - - | loop i = 0, N, 1 - | T[i+1][i] = ... - | ... = T[i][i] - | endloop - */ - if (init_v[index] != 0 && dist_v[index] != dist) - { - finalize_ddr_dependent (ddr, chrec_known); - return false; - } - - dist_v[index] = dist; - init_v[index] = 1; - *init_b = true; - } - else if (!operand_equal_p (access_fn_a, access_fn_b, 0)) - { - /* This can be for example an affine vs. constant dependence - (T[i] vs. T[3]) that is not an affine dependence and is - not representable as a distance vector. */ - non_affine_dependence_relation (ddr); - return false; - } - else - *init_b = true; - } - - return true; -} - -/* Return true when the DDR contains only invariant access functions wrto. loop - number LNUM. */ - -static bool -invariant_access_functions (const struct data_dependence_relation *ddr, - int lnum) -{ - for (subscript *sub : DDR_SUBSCRIPTS (ddr)) - if (!evolution_function_is_invariant_p (SUB_ACCESS_FN (sub, 0), lnum) - || !evolution_function_is_invariant_p (SUB_ACCESS_FN (sub, 1), lnum)) - return false; - - return true; -} - -/* Helper function for the case where DDR_A and DDR_B are the same - multivariate access function with a constant step. For an example - see pr34635-1.c. */ - -static void -add_multivariate_self_dist (struct data_dependence_relation *ddr, tree c_2) -{ - int x_1, x_2; - tree c_1 = CHREC_LEFT (c_2); - tree c_0 = CHREC_LEFT (c_1); - lambda_vector dist_v; - HOST_WIDE_INT v1, v2, cd; - - /* Polynomials with more than 2 variables are not handled yet. When - the evolution steps are parameters, it is not possible to - represent the dependence using classical distance vectors. */ - if (TREE_CODE (c_0) != INTEGER_CST - || TREE_CODE (CHREC_RIGHT (c_1)) != INTEGER_CST - || TREE_CODE (CHREC_RIGHT (c_2)) != INTEGER_CST) - { - DDR_AFFINE_P (ddr) = false; - return; - } - - x_2 = index_in_loop_nest (CHREC_VARIABLE (c_2), DDR_LOOP_NEST (ddr)); - x_1 = index_in_loop_nest (CHREC_VARIABLE (c_1), DDR_LOOP_NEST (ddr)); - - /* For "{{0, +, 2}_1, +, 3}_2" the distance vector is (3, -2). */ - dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - v1 = int_cst_value (CHREC_RIGHT (c_1)); - v2 = int_cst_value (CHREC_RIGHT (c_2)); - cd = gcd (v1, v2); - v1 /= cd; - v2 /= cd; - - if (v2 < 0) - { - v2 = -v2; - v1 = -v1; - } - - dist_v[x_1] = v2; - dist_v[x_2] = -v1; - save_dist_v (ddr, dist_v); - - add_outer_distances (ddr, dist_v, x_1); -} - -/* Helper function for the case where DDR_A and DDR_B are the same - access functions. */ - -static void -add_other_self_distances (struct data_dependence_relation *ddr) -{ - lambda_vector dist_v; - unsigned i; - int index_carry = DDR_NB_LOOPS (ddr); - subscript *sub; - class loop *loop = DDR_LOOP_NEST (ddr)[0]; - - FOR_EACH_VEC_ELT (DDR_SUBSCRIPTS (ddr), i, sub) - { - tree access_fun = SUB_ACCESS_FN (sub, 0); - - if (TREE_CODE (access_fun) == POLYNOMIAL_CHREC) - { - if (!evolution_function_is_univariate_p (access_fun, loop->num)) - { - if (DDR_NUM_SUBSCRIPTS (ddr) != 1) - { - DDR_ARE_DEPENDENT (ddr) = chrec_dont_know; - return; - } - - access_fun = SUB_ACCESS_FN (DDR_SUBSCRIPT (ddr, 0), 0); - - if (TREE_CODE (CHREC_LEFT (access_fun)) == POLYNOMIAL_CHREC) - add_multivariate_self_dist (ddr, access_fun); - else - /* The evolution step is not constant: it varies in - the outer loop, so this cannot be represented by a - distance vector. For example in pr34635.c the - evolution is {0, +, {0, +, 4}_1}_2. */ - DDR_AFFINE_P (ddr) = false; - - return; - } - - /* When data references are collected in a loop while data - dependences are analyzed in loop nest nested in the loop, we - would have more number of access functions than number of - loops. Skip access functions of loops not in the loop nest. - - See PR89725 for more information. */ - if (flow_loop_nested_p (get_loop (cfun, CHREC_VARIABLE (access_fun)), - loop)) - continue; - - index_carry = MIN (index_carry, - index_in_loop_nest (CHREC_VARIABLE (access_fun), - DDR_LOOP_NEST (ddr))); - } - } - - dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - add_outer_distances (ddr, dist_v, index_carry); -} - -static void -insert_innermost_unit_dist_vector (struct data_dependence_relation *ddr) -{ - lambda_vector dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - - dist_v[0] = 1; - save_dist_v (ddr, dist_v); -} - -/* Adds a unit distance vector to DDR when there is a 0 overlap. This - is the case for example when access functions are the same and - equal to a constant, as in: - - | loop_1 - | A[3] = ... - | ... = A[3] - | endloop_1 - - in which case the distance vectors are (0) and (1). */ - -static void -add_distance_for_zero_overlaps (struct data_dependence_relation *ddr) -{ - unsigned i, j; - - for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) - { - subscript_p sub = DDR_SUBSCRIPT (ddr, i); - conflict_function *ca = SUB_CONFLICTS_IN_A (sub); - conflict_function *cb = SUB_CONFLICTS_IN_B (sub); - - for (j = 0; j < ca->n; j++) - if (affine_function_zero_p (ca->fns[j])) - { - insert_innermost_unit_dist_vector (ddr); - return; - } - - for (j = 0; j < cb->n; j++) - if (affine_function_zero_p (cb->fns[j])) - { - insert_innermost_unit_dist_vector (ddr); - return; - } - } -} - -/* Return true when the DDR contains two data references that have the - same access functions. */ - -static inline bool -same_access_functions (const struct data_dependence_relation *ddr) -{ - for (subscript *sub : DDR_SUBSCRIPTS (ddr)) - if (!eq_evolutions_p (SUB_ACCESS_FN (sub, 0), - SUB_ACCESS_FN (sub, 1))) - return false; - - return true; -} - -/* Compute the classic per loop distance vector. DDR is the data - dependence relation to build a vector from. Return false when fail - to represent the data dependence as a distance vector. */ - -static bool -build_classic_dist_vector (struct data_dependence_relation *ddr, - class loop *loop_nest) -{ - bool init_b = false; - int index_carry = DDR_NB_LOOPS (ddr); - lambda_vector dist_v; - - if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE) - return false; - - if (same_access_functions (ddr)) - { - /* Save the 0 vector. */ - dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - save_dist_v (ddr, dist_v); - - if (invariant_access_functions (ddr, loop_nest->num)) - add_distance_for_zero_overlaps (ddr); - - if (DDR_NB_LOOPS (ddr) > 1) - add_other_self_distances (ddr); - - return true; - } - - dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - if (!build_classic_dist_vector_1 (ddr, 0, 1, dist_v, &init_b, &index_carry)) - return false; - - /* Save the distance vector if we initialized one. */ - if (init_b) - { - /* Verify a basic constraint: classic distance vectors should - always be lexicographically positive. - - Data references are collected in the order of execution of - the program, thus for the following loop - - | for (i = 1; i < 100; i++) - | for (j = 1; j < 100; j++) - | { - | t = T[j+1][i-1]; // A - | T[j][i] = t + 2; // B - | } - - references are collected following the direction of the wind: - A then B. The data dependence tests are performed also - following this order, such that we're looking at the distance - separating the elements accessed by A from the elements later - accessed by B. But in this example, the distance returned by - test_dep (A, B) is lexicographically negative (-1, 1), that - means that the access A occurs later than B with respect to - the outer loop, ie. we're actually looking upwind. In this - case we solve test_dep (B, A) looking downwind to the - lexicographically positive solution, that returns the - distance vector (1, -1). */ - if (!lambda_vector_lexico_pos (dist_v, DDR_NB_LOOPS (ddr))) - { - lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - if (!subscript_dependence_tester_1 (ddr, 1, 0, loop_nest)) - return false; - compute_subscript_distance (ddr); - if (!build_classic_dist_vector_1 (ddr, 1, 0, save_v, &init_b, - &index_carry)) - return false; - save_dist_v (ddr, save_v); - DDR_REVERSED_P (ddr) = true; - - /* In this case there is a dependence forward for all the - outer loops: - - | for (k = 1; k < 100; k++) - | for (i = 1; i < 100; i++) - | for (j = 1; j < 100; j++) - | { - | t = T[j+1][i-1]; // A - | T[j][i] = t + 2; // B - | } - - the vectors are: - (0, 1, -1) - (1, 1, -1) - (1, -1, 1) - */ - if (DDR_NB_LOOPS (ddr) > 1) - { - add_outer_distances (ddr, save_v, index_carry); - add_outer_distances (ddr, dist_v, index_carry); - } - } - else - { - lambda_vector save_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - lambda_vector_copy (dist_v, save_v, DDR_NB_LOOPS (ddr)); - - if (DDR_NB_LOOPS (ddr) > 1) - { - lambda_vector opposite_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - - if (!subscript_dependence_tester_1 (ddr, 1, 0, loop_nest)) - return false; - compute_subscript_distance (ddr); - if (!build_classic_dist_vector_1 (ddr, 1, 0, opposite_v, &init_b, - &index_carry)) - return false; - - save_dist_v (ddr, save_v); - add_outer_distances (ddr, dist_v, index_carry); - add_outer_distances (ddr, opposite_v, index_carry); - } - else - save_dist_v (ddr, save_v); - } - } - else - { - /* There is a distance of 1 on all the outer loops: Example: - there is a dependence of distance 1 on loop_1 for the array A. - - | loop_1 - | A[5] = ... - | endloop - */ - add_outer_distances (ddr, dist_v, - lambda_vector_first_nz (dist_v, - DDR_NB_LOOPS (ddr), 0)); - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - unsigned i; - - fprintf (dump_file, "(build_classic_dist_vector\n"); - for (i = 0; i < DDR_NUM_DIST_VECTS (ddr); i++) - { - fprintf (dump_file, " dist_vector = ("); - print_lambda_vector (dump_file, DDR_DIST_VECT (ddr, i), - DDR_NB_LOOPS (ddr)); - fprintf (dump_file, " )\n"); - } - fprintf (dump_file, ")\n"); - } - - return true; -} - -/* Return the direction for a given distance. - FIXME: Computing dir this way is suboptimal, since dir can catch - cases that dist is unable to represent. */ - -static inline enum data_dependence_direction -dir_from_dist (int dist) -{ - if (dist > 0) - return dir_positive; - else if (dist < 0) - return dir_negative; - else - return dir_equal; -} - -/* Compute the classic per loop direction vector. DDR is the data - dependence relation to build a vector from. */ - -static void -build_classic_dir_vector (struct data_dependence_relation *ddr) -{ - unsigned i, j; - lambda_vector dist_v; - - FOR_EACH_VEC_ELT (DDR_DIST_VECTS (ddr), i, dist_v) - { - lambda_vector dir_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); - - for (j = 0; j < DDR_NB_LOOPS (ddr); j++) - dir_v[j] = dir_from_dist (dist_v[j]); - - save_dir_v (ddr, dir_v); - } -} - -/* Helper function. Returns true when there is a dependence between the - data references. A_INDEX is the index of the first reference (0 for - DDR_A, 1 for DDR_B) and B_INDEX is the index of the second reference. */ - -static bool -subscript_dependence_tester_1 (struct data_dependence_relation *ddr, - unsigned int a_index, unsigned int b_index, - class loop *loop_nest) -{ - unsigned int i; - tree last_conflicts; - struct subscript *subscript; - tree res = NULL_TREE; - - for (i = 0; DDR_SUBSCRIPTS (ddr).iterate (i, &subscript); i++) - { - conflict_function *overlaps_a, *overlaps_b; - - analyze_overlapping_iterations (SUB_ACCESS_FN (subscript, a_index), - SUB_ACCESS_FN (subscript, b_index), - &overlaps_a, &overlaps_b, - &last_conflicts, loop_nest); - - if (SUB_CONFLICTS_IN_A (subscript)) - free_conflict_function (SUB_CONFLICTS_IN_A (subscript)); - if (SUB_CONFLICTS_IN_B (subscript)) - free_conflict_function (SUB_CONFLICTS_IN_B (subscript)); - - SUB_CONFLICTS_IN_A (subscript) = overlaps_a; - SUB_CONFLICTS_IN_B (subscript) = overlaps_b; - SUB_LAST_CONFLICT (subscript) = last_conflicts; - - /* If there is any undetermined conflict function we have to - give a conservative answer in case we cannot prove that - no dependence exists when analyzing another subscript. */ - if (CF_NOT_KNOWN_P (overlaps_a) - || CF_NOT_KNOWN_P (overlaps_b)) - { - res = chrec_dont_know; - continue; - } - - /* When there is a subscript with no dependence we can stop. */ - else if (CF_NO_DEPENDENCE_P (overlaps_a) - || CF_NO_DEPENDENCE_P (overlaps_b)) - { - res = chrec_known; - break; - } - } - - if (res == NULL_TREE) - return true; - - if (res == chrec_known) - dependence_stats.num_dependence_independent++; - else - dependence_stats.num_dependence_undetermined++; - finalize_ddr_dependent (ddr, res); - return false; -} - -/* Computes the conflicting iterations in LOOP_NEST, and initialize DDR. */ - -static void -subscript_dependence_tester (struct data_dependence_relation *ddr, - class loop *loop_nest) -{ - if (subscript_dependence_tester_1 (ddr, 0, 1, loop_nest)) - dependence_stats.num_dependence_dependent++; - - compute_subscript_distance (ddr); - if (build_classic_dist_vector (ddr, loop_nest)) - build_classic_dir_vector (ddr); -} - -/* Returns true when all the access functions of A are affine or - constant with respect to LOOP_NEST. */ - -static bool -access_functions_are_affine_or_constant_p (const struct data_reference *a, - const class loop *loop_nest) -{ - vec<tree> fns = DR_ACCESS_FNS (a); - for (tree t : fns) - if (!evolution_function_is_invariant_p (t, loop_nest->num) - && !evolution_function_is_affine_multivariate_p (t, loop_nest->num)) - return false; - - return true; -} - -/* This computes the affine dependence relation between A and B with - respect to LOOP_NEST. CHREC_KNOWN is used for representing the - independence between two accesses, while CHREC_DONT_KNOW is used - for representing the unknown relation. - - Note that it is possible to stop the computation of the dependence - relation the first time we detect a CHREC_KNOWN element for a given - subscript. */ - -void -compute_affine_dependence (struct data_dependence_relation *ddr, - class loop *loop_nest) -{ - struct data_reference *dra = DDR_A (ddr); - struct data_reference *drb = DDR_B (ddr); - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "(compute_affine_dependence\n"); - fprintf (dump_file, " ref_a: "); - print_generic_expr (dump_file, DR_REF (dra)); - fprintf (dump_file, ", stmt_a: "); - print_gimple_stmt (dump_file, DR_STMT (dra), 0, TDF_SLIM); - fprintf (dump_file, " ref_b: "); - print_generic_expr (dump_file, DR_REF (drb)); - fprintf (dump_file, ", stmt_b: "); - print_gimple_stmt (dump_file, DR_STMT (drb), 0, TDF_SLIM); - } - - /* Analyze only when the dependence relation is not yet known. */ - if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) - { - dependence_stats.num_dependence_tests++; - - if (access_functions_are_affine_or_constant_p (dra, loop_nest) - && access_functions_are_affine_or_constant_p (drb, loop_nest)) - subscript_dependence_tester (ddr, loop_nest); - - /* As a last case, if the dependence cannot be determined, or if - the dependence is considered too difficult to determine, answer - "don't know". */ - else - { - dependence_stats.num_dependence_undetermined++; - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - fprintf (dump_file, "Data ref a:\n"); - dump_data_reference (dump_file, dra); - fprintf (dump_file, "Data ref b:\n"); - dump_data_reference (dump_file, drb); - fprintf (dump_file, "affine dependence test not usable: access function not affine or constant.\n"); - } - finalize_ddr_dependent (ddr, chrec_dont_know); - } - } - - if (dump_file && (dump_flags & TDF_DETAILS)) - { - if (DDR_ARE_DEPENDENT (ddr) == chrec_known) - fprintf (dump_file, ") -> no dependence\n"); - else if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) - fprintf (dump_file, ") -> dependence analysis failed\n"); - else - fprintf (dump_file, ")\n"); - } -} - -/* Compute in DEPENDENCE_RELATIONS the data dependence graph for all - the data references in DATAREFS, in the LOOP_NEST. When - COMPUTE_SELF_AND_RR is FALSE, don't compute read-read and self - relations. Return true when successful, i.e. data references number - is small enough to be handled. */ - -bool -compute_all_dependences (const vec<data_reference_p> &datarefs, - vec<ddr_p> *dependence_relations, - const vec<loop_p> &loop_nest, - bool compute_self_and_rr) -{ - struct data_dependence_relation *ddr; - struct data_reference *a, *b; - unsigned int i, j; - - if ((int) datarefs.length () - > param_loop_max_datarefs_for_datadeps) - { - struct data_dependence_relation *ddr; - - /* Insert a single relation into dependence_relations: - chrec_dont_know. */ - ddr = initialize_data_dependence_relation (NULL, NULL, loop_nest); - dependence_relations->safe_push (ddr); - return false; - } - - FOR_EACH_VEC_ELT (datarefs, i, a) - for (j = i + 1; datarefs.iterate (j, &b); j++) - if (DR_IS_WRITE (a) || DR_IS_WRITE (b) || compute_self_and_rr) - { - ddr = initialize_data_dependence_relation (a, b, loop_nest); - dependence_relations->safe_push (ddr); - if (loop_nest.exists ()) - compute_affine_dependence (ddr, loop_nest[0]); - } - - if (compute_self_and_rr) - FOR_EACH_VEC_ELT (datarefs, i, a) - { - ddr = initialize_data_dependence_relation (a, a, loop_nest); - dependence_relations->safe_push (ddr); - if (loop_nest.exists ()) - compute_affine_dependence (ddr, loop_nest[0]); - } - - return true; -} - -/* Describes a location of a memory reference. */ - -struct data_ref_loc -{ - /* The memory reference. */ - tree ref; - - /* True if the memory reference is read. */ - bool is_read; - - /* True if the data reference is conditional within the containing - statement, i.e. if it might not occur even when the statement - is executed and runs to completion. */ - bool is_conditional_in_stmt; -}; - - -/* Stores the locations of memory references in STMT to REFERENCES. Returns - true if STMT clobbers memory, false otherwise. */ - -static bool -get_references_in_stmt (gimple *stmt, vec<data_ref_loc, va_heap> *references) -{ - bool clobbers_memory = false; - data_ref_loc ref; - tree op0, op1; - enum gimple_code stmt_code = gimple_code (stmt); - - /* ASM_EXPR and CALL_EXPR may embed arbitrary side effects. - As we cannot model data-references to not spelled out - accesses give up if they may occur. */ - if (stmt_code == GIMPLE_CALL - && !(gimple_call_flags (stmt) & ECF_CONST)) - { - /* Allow IFN_GOMP_SIMD_LANE in their own loops. */ - if (gimple_call_internal_p (stmt)) - switch (gimple_call_internal_fn (stmt)) - { - case IFN_GOMP_SIMD_LANE: - { - class loop *loop = gimple_bb (stmt)->loop_father; - tree uid = gimple_call_arg (stmt, 0); - gcc_assert (TREE_CODE (uid) == SSA_NAME); - if (loop == NULL - || loop->simduid != SSA_NAME_VAR (uid)) - clobbers_memory = true; - break; - } - case IFN_MASK_LOAD: - case IFN_MASK_STORE: - break; - default: - clobbers_memory = true; - break; - } - else - clobbers_memory = true; - } - else if (stmt_code == GIMPLE_ASM - && (gimple_asm_volatile_p (as_a <gasm *> (stmt)) - || gimple_vuse (stmt))) - clobbers_memory = true; - - if (!gimple_vuse (stmt)) - return clobbers_memory; - - if (stmt_code == GIMPLE_ASSIGN) - { - tree base; - op0 = gimple_assign_lhs (stmt); - op1 = gimple_assign_rhs1 (stmt); - - if (DECL_P (op1) - || (REFERENCE_CLASS_P (op1) - && (base = get_base_address (op1)) - && TREE_CODE (base) != SSA_NAME - && !is_gimple_min_invariant (base))) - { - ref.ref = op1; - ref.is_read = true; - ref.is_conditional_in_stmt = false; - references->safe_push (ref); - } - } - else if (stmt_code == GIMPLE_CALL) - { - unsigned i, n; - tree ptr, type; - unsigned int align; - - ref.is_read = false; - if (gimple_call_internal_p (stmt)) - switch (gimple_call_internal_fn (stmt)) - { - case IFN_MASK_LOAD: - if (gimple_call_lhs (stmt) == NULL_TREE) - break; - ref.is_read = true; - /* FALLTHRU */ - case IFN_MASK_STORE: - ptr = build_int_cst (TREE_TYPE (gimple_call_arg (stmt, 1)), 0); - align = tree_to_shwi (gimple_call_arg (stmt, 1)); - if (ref.is_read) - type = TREE_TYPE (gimple_call_lhs (stmt)); - else - type = TREE_TYPE (gimple_call_arg (stmt, 3)); - if (TYPE_ALIGN (type) != align) - type = build_aligned_type (type, align); - ref.is_conditional_in_stmt = true; - ref.ref = fold_build2 (MEM_REF, type, gimple_call_arg (stmt, 0), - ptr); - references->safe_push (ref); - return false; - default: - break; - } - - op0 = gimple_call_lhs (stmt); - n = gimple_call_num_args (stmt); - for (i = 0; i < n; i++) - { - op1 = gimple_call_arg (stmt, i); - - if (DECL_P (op1) - || (REFERENCE_CLASS_P (op1) && get_base_address (op1))) - { - ref.ref = op1; - ref.is_read = true; - ref.is_conditional_in_stmt = false; - references->safe_push (ref); - } - } - } - else - return clobbers_memory; - - if (op0 - && (DECL_P (op0) - || (REFERENCE_CLASS_P (op0) && get_base_address (op0)))) - { - ref.ref = op0; - ref.is_read = false; - ref.is_conditional_in_stmt = false; - references->safe_push (ref); - } - return clobbers_memory; -} - - -/* Returns true if the loop-nest has any data reference. */ - -bool -loop_nest_has_data_refs (loop_p loop) -{ - basic_block *bbs = get_loop_body (loop); - auto_vec<data_ref_loc, 3> references; - - for (unsigned i = 0; i < loop->num_nodes; i++) - { - basic_block bb = bbs[i]; - gimple_stmt_iterator bsi; - - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - { - gimple *stmt = gsi_stmt (bsi); - get_references_in_stmt (stmt, &references); - if (references.length ()) - { - free (bbs); - return true; - } - } - } - free (bbs); - return false; -} - -/* Stores the data references in STMT to DATAREFS. If there is an unanalyzable - reference, returns false, otherwise returns true. NEST is the outermost - loop of the loop nest in which the references should be analyzed. */ - -opt_result -find_data_references_in_stmt (class loop *nest, gimple *stmt, - vec<data_reference_p> *datarefs) -{ - auto_vec<data_ref_loc, 2> references; - data_reference_p dr; - - if (get_references_in_stmt (stmt, &references)) - return opt_result::failure_at (stmt, "statement clobbers memory: %G", - stmt); - - for (const data_ref_loc &ref : references) - { - dr = create_data_ref (nest ? loop_preheader_edge (nest) : NULL, - loop_containing_stmt (stmt), ref.ref, - stmt, ref.is_read, ref.is_conditional_in_stmt); - gcc_assert (dr != NULL); - datarefs->safe_push (dr); - } - - return opt_result::success (); -} - -/* Stores the data references in STMT to DATAREFS. If there is an - unanalyzable reference, returns false, otherwise returns true. - NEST is the outermost loop of the loop nest in which the references - should be instantiated, LOOP is the loop in which the references - should be analyzed. */ - -bool -graphite_find_data_references_in_stmt (edge nest, loop_p loop, gimple *stmt, - vec<data_reference_p> *datarefs) -{ - auto_vec<data_ref_loc, 2> references; - bool ret = true; - data_reference_p dr; - - if (get_references_in_stmt (stmt, &references)) - return false; - - for (const data_ref_loc &ref : references) - { - dr = create_data_ref (nest, loop, ref.ref, stmt, ref.is_read, - ref.is_conditional_in_stmt); - gcc_assert (dr != NULL); - datarefs->safe_push (dr); - } - - return ret; -} - -/* Search the data references in LOOP, and record the information into - DATAREFS. Returns chrec_dont_know when failing to analyze a - difficult case, returns NULL_TREE otherwise. */ - -tree -find_data_references_in_bb (class loop *loop, basic_block bb, - vec<data_reference_p> *datarefs) -{ - gimple_stmt_iterator bsi; - - for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) - { - gimple *stmt = gsi_stmt (bsi); - - if (!find_data_references_in_stmt (loop, stmt, datarefs)) - { - struct data_reference *res; - res = XCNEW (struct data_reference); - datarefs->safe_push (res); - - return chrec_dont_know; - } - } - - return NULL_TREE; -} - -/* Search the data references in LOOP, and record the information into - DATAREFS. Returns chrec_dont_know when failing to analyze a - difficult case, returns NULL_TREE otherwise. - - TODO: This function should be made smarter so that it can handle address - arithmetic as if they were array accesses, etc. */ - -tree -find_data_references_in_loop (class loop *loop, - vec<data_reference_p> *datarefs) -{ - basic_block bb, *bbs; - unsigned int i; - - bbs = get_loop_body_in_dom_order (loop); - - for (i = 0; i < loop->num_nodes; i++) - { - bb = bbs[i]; - - if (find_data_references_in_bb (loop, bb, datarefs) == chrec_dont_know) - { - free (bbs); - return chrec_dont_know; - } - } - free (bbs); - - return NULL_TREE; -} - -/* Return the alignment in bytes that DRB is guaranteed to have at all - times. */ - -unsigned int -dr_alignment (innermost_loop_behavior *drb) -{ - /* Get the alignment of BASE_ADDRESS + INIT. */ - unsigned int alignment = drb->base_alignment; - unsigned int misalignment = (drb->base_misalignment - + TREE_INT_CST_LOW (drb->init)); - if (misalignment != 0) - alignment = MIN (alignment, misalignment & -misalignment); - - /* Cap it to the alignment of OFFSET. */ - if (!integer_zerop (drb->offset)) - alignment = MIN (alignment, drb->offset_alignment); - - /* Cap it to the alignment of STEP. */ - if (!integer_zerop (drb->step)) - alignment = MIN (alignment, drb->step_alignment); - - return alignment; -} - -/* If BASE is a pointer-typed SSA name, try to find the object that it - is based on. Return this object X on success and store the alignment - in bytes of BASE - &X in *ALIGNMENT_OUT. */ - -static tree -get_base_for_alignment_1 (tree base, unsigned int *alignment_out) -{ - if (TREE_CODE (base) != SSA_NAME || !POINTER_TYPE_P (TREE_TYPE (base))) - return NULL_TREE; - - gimple *def = SSA_NAME_DEF_STMT (base); - base = analyze_scalar_evolution (loop_containing_stmt (def), base); - - /* Peel chrecs and record the minimum alignment preserved by - all steps. */ - unsigned int alignment = MAX_OFILE_ALIGNMENT / BITS_PER_UNIT; - while (TREE_CODE (base) == POLYNOMIAL_CHREC) - { - unsigned int step_alignment = highest_pow2_factor (CHREC_RIGHT (base)); - alignment = MIN (alignment, step_alignment); - base = CHREC_LEFT (base); - } - - /* Punt if the expression is too complicated to handle. */ - if (tree_contains_chrecs (base, NULL) || !POINTER_TYPE_P (TREE_TYPE (base))) - return NULL_TREE; - - /* The only useful cases are those for which a dereference folds to something - other than an INDIRECT_REF. */ - tree ref_type = TREE_TYPE (TREE_TYPE (base)); - tree ref = fold_indirect_ref_1 (UNKNOWN_LOCATION, ref_type, base); - if (!ref) - return NULL_TREE; - - /* Analyze the base to which the steps we peeled were applied. */ - poly_int64 bitsize, bitpos, bytepos; - machine_mode mode; - int unsignedp, reversep, volatilep; - tree offset; - base = get_inner_reference (ref, &bitsize, &bitpos, &offset, &mode, - &unsignedp, &reversep, &volatilep); - if (!base || !multiple_p (bitpos, BITS_PER_UNIT, &bytepos)) - return NULL_TREE; - - /* Restrict the alignment to that guaranteed by the offsets. */ - unsigned int bytepos_alignment = known_alignment (bytepos); - if (bytepos_alignment != 0) - alignment = MIN (alignment, bytepos_alignment); - if (offset) - { - unsigned int offset_alignment = highest_pow2_factor (offset); - alignment = MIN (alignment, offset_alignment); - } - - *alignment_out = alignment; - return base; -} - -/* Return the object whose alignment would need to be changed in order - to increase the alignment of ADDR. Store the maximum achievable - alignment in *MAX_ALIGNMENT. */ - -tree -get_base_for_alignment (tree addr, unsigned int *max_alignment) -{ - tree base = get_base_for_alignment_1 (addr, max_alignment); - if (base) - return base; - - if (TREE_CODE (addr) == ADDR_EXPR) - addr = TREE_OPERAND (addr, 0); - *max_alignment = MAX_OFILE_ALIGNMENT / BITS_PER_UNIT; - return addr; -} - -/* Recursive helper function. */ - -static bool -find_loop_nest_1 (class loop *loop, vec<loop_p> *loop_nest) -{ - /* Inner loops of the nest should not contain siblings. Example: - when there are two consecutive loops, - - | loop_0 - | loop_1 - | A[{0, +, 1}_1] - | endloop_1 - | loop_2 - | A[{0, +, 1}_2] - | endloop_2 - | endloop_0 - - the dependence relation cannot be captured by the distance - abstraction. */ - if (loop->next) - return false; - - loop_nest->safe_push (loop); - if (loop->inner) - return find_loop_nest_1 (loop->inner, loop_nest); - return true; -} - -/* Return false when the LOOP is not well nested. Otherwise return - true and insert in LOOP_NEST the loops of the nest. LOOP_NEST will - contain the loops from the outermost to the innermost, as they will - appear in the classic distance vector. */ - -bool -find_loop_nest (class loop *loop, vec<loop_p> *loop_nest) -{ - loop_nest->safe_push (loop); - if (loop->inner) - return find_loop_nest_1 (loop->inner, loop_nest); - return true; -} - -/* Returns true when the data dependences have been computed, false otherwise. - Given a loop nest LOOP, the following vectors are returned: - DATAREFS is initialized to all the array elements contained in this loop, - DEPENDENCE_RELATIONS contains the relations between the data references. - Compute read-read and self relations if - COMPUTE_SELF_AND_READ_READ_DEPENDENCES is TRUE. */ - -bool -compute_data_dependences_for_loop (class loop *loop, - bool compute_self_and_read_read_dependences, - vec<loop_p> *loop_nest, - vec<data_reference_p> *datarefs, - vec<ddr_p> *dependence_relations) -{ - bool res = true; - - memset (&dependence_stats, 0, sizeof (dependence_stats)); - - /* If the loop nest is not well formed, or one of the data references - is not computable, give up without spending time to compute other - dependences. */ - if (!loop - || !find_loop_nest (loop, loop_nest) - || find_data_references_in_loop (loop, datarefs) == chrec_dont_know - || !compute_all_dependences (*datarefs, dependence_relations, *loop_nest, - compute_self_and_read_read_dependences)) - res = false; - - if (dump_file && (dump_flags & TDF_STATS)) - { - fprintf (dump_file, "Dependence tester statistics:\n"); - - fprintf (dump_file, "Number of dependence tests: %d\n", - dependence_stats.num_dependence_tests); - fprintf (dump_file, "Number of dependence tests classified dependent: %d\n", - dependence_stats.num_dependence_dependent); - fprintf (dump_file, "Number of dependence tests classified independent: %d\n", - dependence_stats.num_dependence_independent); - fprintf (dump_file, "Number of undetermined dependence tests: %d\n", - dependence_stats.num_dependence_undetermined); - - fprintf (dump_file, "Number of subscript tests: %d\n", - dependence_stats.num_subscript_tests); - fprintf (dump_file, "Number of undetermined subscript tests: %d\n", - dependence_stats.num_subscript_undetermined); - fprintf (dump_file, "Number of same subscript function: %d\n", - dependence_stats.num_same_subscript_function); - - fprintf (dump_file, "Number of ziv tests: %d\n", - dependence_stats.num_ziv); - fprintf (dump_file, "Number of ziv tests returning dependent: %d\n", - dependence_stats.num_ziv_dependent); - fprintf (dump_file, "Number of ziv tests returning independent: %d\n", - dependence_stats.num_ziv_independent); - fprintf (dump_file, "Number of ziv tests unimplemented: %d\n", - dependence_stats.num_ziv_unimplemented); - - fprintf (dump_file, "Number of siv tests: %d\n", - dependence_stats.num_siv); - fprintf (dump_file, "Number of siv tests returning dependent: %d\n", - dependence_stats.num_siv_dependent); - fprintf (dump_file, "Number of siv tests returning independent: %d\n", - dependence_stats.num_siv_independent); - fprintf (dump_file, "Number of siv tests unimplemented: %d\n", - dependence_stats.num_siv_unimplemented); - - fprintf (dump_file, "Number of miv tests: %d\n", - dependence_stats.num_miv); - fprintf (dump_file, "Number of miv tests returning dependent: %d\n", - dependence_stats.num_miv_dependent); - fprintf (dump_file, "Number of miv tests returning independent: %d\n", - dependence_stats.num_miv_independent); - fprintf (dump_file, "Number of miv tests unimplemented: %d\n", - dependence_stats.num_miv_unimplemented); - } - - return res; -} - -/* Free the memory used by a data dependence relation DDR. */ - -void -free_dependence_relation (struct data_dependence_relation *ddr) -{ - if (ddr == NULL) - return; - - if (DDR_SUBSCRIPTS (ddr).exists ()) - free_subscripts (DDR_SUBSCRIPTS (ddr)); - DDR_DIST_VECTS (ddr).release (); - DDR_DIR_VECTS (ddr).release (); - - free (ddr); -} - -/* Free the memory used by the data dependence relations from - DEPENDENCE_RELATIONS. */ - -void -free_dependence_relations (vec<ddr_p>& dependence_relations) -{ - for (data_dependence_relation *ddr : dependence_relations) - if (ddr) - free_dependence_relation (ddr); - - dependence_relations.release (); -} - -/* Free the memory used by the data references from DATAREFS. */ - -void -free_data_refs (vec<data_reference_p>& datarefs) -{ - for (data_reference *dr : datarefs) - free_data_ref (dr); - datarefs.release (); -} - -/* Common routine implementing both dr_direction_indicator and - dr_zero_step_indicator. Return USEFUL_MIN if the indicator is known - to be >= USEFUL_MIN and -1 if the indicator is known to be negative. - Return the step as the indicator otherwise. */ - -static tree -dr_step_indicator (struct data_reference *dr, int useful_min) -{ - tree step = DR_STEP (dr); - if (!step) - return NULL_TREE; - STRIP_NOPS (step); - /* Look for cases where the step is scaled by a positive constant - integer, which will often be the access size. If the multiplication - doesn't change the sign (due to overflow effects) then we can - test the unscaled value instead. */ - if (TREE_CODE (step) == MULT_EXPR - && TREE_CODE (TREE_OPERAND (step, 1)) == INTEGER_CST - && tree_int_cst_sgn (TREE_OPERAND (step, 1)) > 0) - { - tree factor = TREE_OPERAND (step, 1); - step = TREE_OPERAND (step, 0); - - /* Strip widening and truncating conversions as well as nops. */ - if (CONVERT_EXPR_P (step) - && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (step, 0)))) - step = TREE_OPERAND (step, 0); - tree type = TREE_TYPE (step); - - /* Get the range of step values that would not cause overflow. */ - widest_int minv = (wi::to_widest (TYPE_MIN_VALUE (ssizetype)) - / wi::to_widest (factor)); - widest_int maxv = (wi::to_widest (TYPE_MAX_VALUE (ssizetype)) - / wi::to_widest (factor)); - - /* Get the range of values that the unconverted step actually has. */ - wide_int step_min, step_max; - value_range vr; - if (TREE_CODE (step) != SSA_NAME - || !get_range_query (cfun)->range_of_expr (vr, step) - || vr.kind () != VR_RANGE) - { - step_min = wi::to_wide (TYPE_MIN_VALUE (type)); - step_max = wi::to_wide (TYPE_MAX_VALUE (type)); - } - else - { - step_min = vr.lower_bound (); - step_max = vr.upper_bound (); - } - - /* Check whether the unconverted step has an acceptable range. */ - signop sgn = TYPE_SIGN (type); - if (wi::les_p (minv, widest_int::from (step_min, sgn)) - && wi::ges_p (maxv, widest_int::from (step_max, sgn))) - { - if (wi::ge_p (step_min, useful_min, sgn)) - return ssize_int (useful_min); - else if (wi::lt_p (step_max, 0, sgn)) - return ssize_int (-1); - else - return fold_convert (ssizetype, step); - } - } - return DR_STEP (dr); -} - -/* Return a value that is negative iff DR has a negative step. */ - -tree -dr_direction_indicator (struct data_reference *dr) -{ - return dr_step_indicator (dr, 0); -} - -/* Return a value that is zero iff DR has a zero step. */ - -tree -dr_zero_step_indicator (struct data_reference *dr) -{ - return dr_step_indicator (dr, 1); -} - -/* Return true if DR is known to have a nonnegative (but possibly zero) - step. */ - -bool -dr_known_forward_stride_p (struct data_reference *dr) -{ - tree indicator = dr_direction_indicator (dr); - tree neg_step_val = fold_binary (LT_EXPR, boolean_type_node, - fold_convert (ssizetype, indicator), - ssize_int (0)); - return neg_step_val && integer_zerop (neg_step_val); -} |