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Diffstat (limited to 'gcc/tree-data-ref.c')
| -rw-r--r-- | gcc/tree-data-ref.c | 4495 |
1 files changed, 4495 insertions, 0 deletions
diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c new file mode 100644 index 0000000..75b5739 --- /dev/null +++ b/gcc/tree-data-ref.c @@ -0,0 +1,4495 @@ + +/* Data references and dependences detectors. + Copyright (C) 2003, 2004, 2005, 2006 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 2, 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 COPYING. If not, write to the Free +Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301, USA. */ + +/* 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 "tm.h" +#include "ggc.h" +#include "tree.h" + +/* These RTL headers are needed for basic-block.h. */ +#include "rtl.h" +#include "basic-block.h" +#include "diagnostic.h" +#include "tree-flow.h" +#include "tree-dump.h" +#include "timevar.h" +#include "cfgloop.h" +#include "tree-chrec.h" +#include "tree-data-ref.h" +#include "tree-scalar-evolution.h" +#include "tree-pass.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 tree object_analysis (tree, tree, bool, struct data_reference **, + tree *, tree *, tree *, tree *, tree *, + struct ptr_info_def **, subvar_t *); +static struct data_reference * init_data_ref (tree, tree, tree, tree, bool, + tree, tree, tree, tree, tree, + struct ptr_info_def *, + enum data_ref_type); +static bool subscript_dependence_tester_1 (struct data_dependence_relation *, + struct data_reference *, + struct data_reference *); + +/* Determine if PTR and DECL may alias, the result is put in ALIASED. + Return FALSE if there is no symbol memory tag for PTR. */ + +static bool +ptr_decl_may_alias_p (tree ptr, tree decl, + struct data_reference *ptr_dr, + bool *aliased) +{ + tree tag = NULL_TREE; + struct ptr_info_def *pi = DR_PTR_INFO (ptr_dr); + + gcc_assert (TREE_CODE (ptr) == SSA_NAME && DECL_P (decl)); + + if (pi) + tag = pi->name_mem_tag; + if (!tag) + tag = get_var_ann (SSA_NAME_VAR (ptr))->symbol_mem_tag; + if (!tag) + tag = DR_MEMTAG (ptr_dr); + if (!tag) + return false; + + *aliased = is_aliased_with (tag, decl); + return true; +} + + +/* Determine if two pointers may alias, the result is put in ALIASED. + Return FALSE if there is no symbol memory tag for one of the pointers. */ + +static bool +ptr_ptr_may_alias_p (tree ptr_a, tree ptr_b, + struct data_reference *dra, + struct data_reference *drb, + bool *aliased) +{ + tree tag_a = NULL_TREE, tag_b = NULL_TREE; + struct ptr_info_def *pi_a = DR_PTR_INFO (dra); + struct ptr_info_def *pi_b = DR_PTR_INFO (drb); + + if (pi_a && pi_a->name_mem_tag && pi_b && pi_b->name_mem_tag) + { + tag_a = pi_a->name_mem_tag; + tag_b = pi_b->name_mem_tag; + } + else + { + tag_a = get_var_ann (SSA_NAME_VAR (ptr_a))->symbol_mem_tag; + if (!tag_a) + tag_a = DR_MEMTAG (dra); + if (!tag_a) + return false; + + tag_b = get_var_ann (SSA_NAME_VAR (ptr_b))->symbol_mem_tag; + if (!tag_b) + tag_b = DR_MEMTAG (drb); + if (!tag_b) + return false; + } + + if (tag_a == tag_b) + *aliased = true; + else + *aliased = may_aliases_intersect (tag_a, tag_b); + + return true; +} + + +/* Determine if BASE_A and BASE_B may alias, the result is put in ALIASED. + Return FALSE if there is no symbol memory tag for one of the symbols. */ + +static bool +may_alias_p (tree base_a, tree base_b, + struct data_reference *dra, + struct data_reference *drb, + bool *aliased) +{ + if (TREE_CODE (base_a) == ADDR_EXPR || TREE_CODE (base_b) == ADDR_EXPR) + { + if (TREE_CODE (base_a) == ADDR_EXPR && TREE_CODE (base_b) == ADDR_EXPR) + { + *aliased = (TREE_OPERAND (base_a, 0) == TREE_OPERAND (base_b, 0)); + return true; + } + if (TREE_CODE (base_a) == ADDR_EXPR) + return ptr_decl_may_alias_p (base_b, TREE_OPERAND (base_a, 0), drb, + aliased); + else + return ptr_decl_may_alias_p (base_a, TREE_OPERAND (base_b, 0), dra, + aliased); + } + + return ptr_ptr_may_alias_p (base_a, base_b, dra, drb, aliased); +} + + +/* Determine if a pointer (BASE_A) and a record/union access (BASE_B) + are not aliased. Return TRUE if they differ. */ +static bool +record_ptr_differ_p (struct data_reference *dra, + struct data_reference *drb) +{ + bool aliased; + tree base_a = DR_BASE_OBJECT (dra); + tree base_b = DR_BASE_OBJECT (drb); + + if (TREE_CODE (base_b) != COMPONENT_REF) + return false; + + /* Peel COMPONENT_REFs to get to the base. Do not peel INDIRECT_REFs. + For a.b.c.d[i] we will get a, and for a.b->c.d[i] we will get a.b. + Probably will be unnecessary with struct alias analysis. */ + while (TREE_CODE (base_b) == COMPONENT_REF) + base_b = TREE_OPERAND (base_b, 0); + /* Compare a record/union access (b.c[i] or p->c[i]) and a pointer + ((*q)[i]). */ + if (TREE_CODE (base_a) == INDIRECT_REF + && ((TREE_CODE (base_b) == VAR_DECL + && (ptr_decl_may_alias_p (TREE_OPERAND (base_a, 0), base_b, dra, + &aliased) + && !aliased)) + || (TREE_CODE (base_b) == INDIRECT_REF + && (ptr_ptr_may_alias_p (TREE_OPERAND (base_a, 0), + TREE_OPERAND (base_b, 0), dra, drb, + &aliased) + && !aliased)))) + return true; + else + return false; +} + +/* Determine if two record/union accesses are aliased. Return TRUE if they + differ. */ +static bool +record_record_differ_p (struct data_reference *dra, + struct data_reference *drb) +{ + bool aliased; + tree base_a = DR_BASE_OBJECT (dra); + tree base_b = DR_BASE_OBJECT (drb); + + if (TREE_CODE (base_b) != COMPONENT_REF + || TREE_CODE (base_a) != COMPONENT_REF) + return false; + + /* Peel COMPONENT_REFs to get to the base. Do not peel INDIRECT_REFs. + For a.b.c.d[i] we will get a, and for a.b->c.d[i] we will get a.b. + Probably will be unnecessary with struct alias analysis. */ + while (TREE_CODE (base_b) == COMPONENT_REF) + base_b = TREE_OPERAND (base_b, 0); + while (TREE_CODE (base_a) == COMPONENT_REF) + base_a = TREE_OPERAND (base_a, 0); + + if (TREE_CODE (base_a) == INDIRECT_REF + && TREE_CODE (base_b) == INDIRECT_REF + && ptr_ptr_may_alias_p (TREE_OPERAND (base_a, 0), + TREE_OPERAND (base_b, 0), + dra, drb, &aliased) + && !aliased) + return true; + else + return false; +} + +/* Determine if an array access (BASE_A) and a record/union access (BASE_B) + are not aliased. Return TRUE if they differ. */ +static bool +record_array_differ_p (struct data_reference *dra, + struct data_reference *drb) +{ + bool aliased; + tree base_a = DR_BASE_OBJECT (dra); + tree base_b = DR_BASE_OBJECT (drb); + + if (TREE_CODE (base_b) != COMPONENT_REF) + return false; + + /* Peel COMPONENT_REFs to get to the base. Do not peel INDIRECT_REFs. + For a.b.c.d[i] we will get a, and for a.b->c.d[i] we will get a.b. + Probably will be unnecessary with struct alias analysis. */ + while (TREE_CODE (base_b) == COMPONENT_REF) + base_b = TREE_OPERAND (base_b, 0); + + /* Compare a record/union access (b.c[i] or p->c[i]) and an array access + (a[i]). In case of p->c[i] use alias analysis to verify that p is not + pointing to a. */ + if (TREE_CODE (base_a) == VAR_DECL + && (TREE_CODE (base_b) == VAR_DECL + || (TREE_CODE (base_b) == INDIRECT_REF + && (ptr_decl_may_alias_p (TREE_OPERAND (base_b, 0), base_a, drb, + &aliased) + && !aliased)))) + return true; + else + return false; +} + + +/* Determine if an array access (BASE_A) and a pointer (BASE_B) + are not aliased. Return TRUE if they differ. */ +static bool +array_ptr_differ_p (tree base_a, tree base_b, + struct data_reference *drb) +{ + bool aliased; + + /* In case one of the bases is a pointer (a[i] and (*p)[i]), we check with the + help of alias analysis that p is not pointing to a. */ + if (TREE_CODE (base_a) == VAR_DECL && TREE_CODE (base_b) == INDIRECT_REF + && (ptr_decl_may_alias_p (TREE_OPERAND (base_b, 0), base_a, drb, &aliased) + && !aliased)) + return true; + else + return false; +} + + +/* This is the simplest data dependence test: determines whether the + data references A and B access the same array/region. Returns + false when the property is not computable at compile time. + Otherwise return true, and DIFFER_P will record the result. This + utility will not be necessary when alias_sets_conflict_p will be + less conservative. */ + +static bool +base_object_differ_p (struct data_reference *a, + struct data_reference *b, + bool *differ_p) +{ + tree base_a = DR_BASE_OBJECT (a); + tree base_b = DR_BASE_OBJECT (b); + bool aliased; + + if (!base_a || !base_b) + return false; + + /* Determine if same base. Example: for the array accesses + a[i], b[i] or pointer accesses *a, *b, bases are a, b. */ + if (base_a == base_b) + { + *differ_p = false; + return true; + } + + /* For pointer based accesses, (*p)[i], (*q)[j], the bases are (*p) + and (*q) */ + if (TREE_CODE (base_a) == INDIRECT_REF && TREE_CODE (base_b) == INDIRECT_REF + && TREE_OPERAND (base_a, 0) == TREE_OPERAND (base_b, 0)) + { + *differ_p = false; + return true; + } + + /* Record/union based accesses - s.a[i], t.b[j]. bases are s.a,t.b. */ + if (TREE_CODE (base_a) == COMPONENT_REF && TREE_CODE (base_b) == COMPONENT_REF + && TREE_OPERAND (base_a, 0) == TREE_OPERAND (base_b, 0) + && TREE_OPERAND (base_a, 1) == TREE_OPERAND (base_b, 1)) + { + *differ_p = false; + return true; + } + + + /* Determine if different bases. */ + + /* At this point we know that base_a != base_b. However, pointer + accesses of the form x=(*p) and y=(*q), whose bases are p and q, + may still be pointing to the same base. In SSAed GIMPLE p and q will + be SSA_NAMES in this case. Therefore, here we check if they are + really two different declarations. */ + if (TREE_CODE (base_a) == VAR_DECL && TREE_CODE (base_b) == VAR_DECL) + { + *differ_p = true; + return true; + } + + /* In case one of the bases is a pointer (a[i] and (*p)[i]), we check with the + help of alias analysis that p is not pointing to a. */ + if (array_ptr_differ_p (base_a, base_b, b) + || array_ptr_differ_p (base_b, base_a, a)) + { + *differ_p = true; + return true; + } + + /* If the bases are pointers ((*q)[i] and (*p)[i]), we check with the + help of alias analysis they don't point to the same bases. */ + if (TREE_CODE (base_a) == INDIRECT_REF && TREE_CODE (base_b) == INDIRECT_REF + && (may_alias_p (TREE_OPERAND (base_a, 0), TREE_OPERAND (base_b, 0), a, b, + &aliased) + && !aliased)) + { + *differ_p = true; + return true; + } + + /* Compare two record/union bases s.a and t.b: s != t or (a != b and + s and t are not unions). */ + if (TREE_CODE (base_a) == COMPONENT_REF && TREE_CODE (base_b) == COMPONENT_REF + && ((TREE_CODE (TREE_OPERAND (base_a, 0)) == VAR_DECL + && TREE_CODE (TREE_OPERAND (base_b, 0)) == VAR_DECL + && TREE_OPERAND (base_a, 0) != TREE_OPERAND (base_b, 0)) + || (TREE_CODE (TREE_TYPE (TREE_OPERAND (base_a, 0))) == RECORD_TYPE + && TREE_CODE (TREE_TYPE (TREE_OPERAND (base_b, 0))) == RECORD_TYPE + && TREE_OPERAND (base_a, 1) != TREE_OPERAND (base_b, 1)))) + { + *differ_p = true; + return true; + } + + /* Compare a record/union access (b.c[i] or p->c[i]) and a pointer + ((*q)[i]). */ + if (record_ptr_differ_p (a, b) || record_ptr_differ_p (b, a)) + { + *differ_p = true; + return true; + } + + /* Compare a record/union access (b.c[i] or p->c[i]) and an array access + (a[i]). In case of p->c[i] use alias analysis to verify that p is not + pointing to a. */ + if (record_array_differ_p (a, b) || record_array_differ_p (b, a)) + { + *differ_p = true; + return true; + } + + /* Compare two record/union accesses (b.c[i] or p->c[i]). */ + if (record_record_differ_p (a, b)) + { + *differ_p = true; + return true; + } + + return false; +} + +/* Function base_addr_differ_p. + + This is the simplest data dependence test: determines whether the + data references DRA and DRB access the same array/region. Returns + false when the property is not computable at compile time. + Otherwise return true, and DIFFER_P will record the result. + + The algorithm: + 1. if (both DRA and DRB are represented as arrays) + compare DRA.BASE_OBJECT and DRB.BASE_OBJECT + 2. else if (both DRA and DRB are represented as pointers) + try to prove that DRA.FIRST_LOCATION == DRB.FIRST_LOCATION + 3. else if (DRA and DRB are represented differently or 2. fails) + only try to prove that the bases are surely different +*/ + +static bool +base_addr_differ_p (struct data_reference *dra, + struct data_reference *drb, + bool *differ_p) +{ + tree addr_a = DR_BASE_ADDRESS (dra); + tree addr_b = DR_BASE_ADDRESS (drb); + tree type_a, type_b; + bool aliased; + + if (!addr_a || !addr_b) + return false; + + type_a = TREE_TYPE (addr_a); + type_b = TREE_TYPE (addr_b); + + gcc_assert (POINTER_TYPE_P (type_a) && POINTER_TYPE_P (type_b)); + + /* 1. if (both DRA and DRB are represented as arrays) + compare DRA.BASE_OBJECT and DRB.BASE_OBJECT. */ + if (DR_TYPE (dra) == ARRAY_REF_TYPE && DR_TYPE (drb) == ARRAY_REF_TYPE) + return base_object_differ_p (dra, drb, differ_p); + + /* 2. else if (both DRA and DRB are represented as pointers) + try to prove that DRA.FIRST_LOCATION == DRB.FIRST_LOCATION. */ + /* If base addresses are the same, we check the offsets, since the access of + the data-ref is described by {base addr + offset} and its access function, + i.e., in order to decide whether the bases of data-refs are the same we + compare both base addresses and offsets. */ + if (DR_TYPE (dra) == POINTER_REF_TYPE && DR_TYPE (drb) == POINTER_REF_TYPE + && (addr_a == addr_b + || (TREE_CODE (addr_a) == ADDR_EXPR && TREE_CODE (addr_b) == ADDR_EXPR + && TREE_OPERAND (addr_a, 0) == TREE_OPERAND (addr_b, 0)))) + { + /* Compare offsets. */ + tree offset_a = DR_OFFSET (dra); + tree offset_b = DR_OFFSET (drb); + + STRIP_NOPS (offset_a); + STRIP_NOPS (offset_b); + + /* FORNOW: we only compare offsets that are MULT_EXPR, i.e., we don't handle + PLUS_EXPR. */ + if (offset_a == offset_b + || (TREE_CODE (offset_a) == MULT_EXPR + && TREE_CODE (offset_b) == MULT_EXPR + && TREE_OPERAND (offset_a, 0) == TREE_OPERAND (offset_b, 0) + && TREE_OPERAND (offset_a, 1) == TREE_OPERAND (offset_b, 1))) + { + *differ_p = false; + return true; + } + } + + /* 3. else if (DRA and DRB are represented differently or 2. fails) + only try to prove that the bases are surely different. */ + + /* Apply alias analysis. */ + if (may_alias_p (addr_a, addr_b, dra, drb, &aliased) && !aliased) + { + *differ_p = true; + return true; + } + + /* An instruction writing through a restricted pointer is "independent" of any + instruction reading or writing through a different pointer, in the same + block/scope. */ + else if ((TYPE_RESTRICT (type_a) && !DR_IS_READ (dra)) + || (TYPE_RESTRICT (type_b) && !DR_IS_READ (drb))) + { + *differ_p = true; + return true; + } + return false; +} + +/* Returns true iff A divides B. */ + +static inline bool +tree_fold_divides_p (tree a, + tree b) +{ + /* Determines whether (A == gcd (A, B)). */ + return tree_int_cst_equal (a, tree_fold_gcd (a, b)); +} + +/* Returns true iff A divides B. */ + +static inline bool +int_divides_p (int a, int b) +{ + return ((b % a) == 0); +} + + + +/* Dump into FILE all the data references from DATAREFS. */ + +void +dump_data_references (FILE *file, VEC (data_reference_p, heap) *datarefs) +{ + unsigned int i; + struct data_reference *dr; + + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) + dump_data_reference (file, dr); +} + +/* Dump into FILE all the dependence relations from DDRS. */ + +void +dump_data_dependence_relations (FILE *file, + VEC (ddr_p, heap) *ddrs) +{ + unsigned int i; + struct data_dependence_relation *ddr; + + for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++) + dump_data_dependence_relation (file, ddr); +} + +/* 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 stmt: "); + print_generic_stmt (outf, DR_STMT (dr), 0); + fprintf (outf, " ref: "); + print_generic_stmt (outf, DR_REF (dr), 0); + fprintf (outf, " base_object: "); + print_generic_stmt (outf, DR_BASE_OBJECT (dr), 0); + + for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++) + { + fprintf (outf, " Access function %d: ", i); + print_generic_stmt (outf, DR_ACCESS_FN (dr, i), 0); + } + fprintf (outf, ")\n"); +} + +/* Dump function for a SUBSCRIPT structure. */ + +void +dump_subscript (FILE *outf, struct subscript *subscript) +{ + tree chrec = SUB_CONFLICTS_IN_A (subscript); + + fprintf (outf, "\n (subscript \n"); + fprintf (outf, " iterations_that_access_an_element_twice_in_A: "); + print_generic_stmt (outf, chrec, 0); + if (chrec == chrec_known) + fprintf (outf, " (no dependence)\n"); + else if (chrec_contains_undetermined (chrec)) + fprintf (outf, " (don't know)\n"); + else + { + tree last_iteration = SUB_LAST_CONFLICT (subscript); + fprintf (outf, " last_conflict: "); + print_generic_stmt (outf, last_iteration, 0); + } + + chrec = SUB_CONFLICTS_IN_B (subscript); + fprintf (outf, " iterations_that_access_an_element_twice_in_B: "); + print_generic_stmt (outf, chrec, 0); + if (chrec == chrec_known) + fprintf (outf, " (no dependence)\n"); + else if (chrec_contains_undetermined (chrec)) + fprintf (outf, " (don't know)\n"); + else + { + tree last_iteration = SUB_LAST_CONFLICT (subscript); + fprintf (outf, " last_conflict: "); + print_generic_stmt (outf, last_iteration, 0); + } + + fprintf (outf, " (Subscript distance: "); + print_generic_stmt (outf, SUB_DISTANCE (subscript), 0); + fprintf (outf, " )\n"); + fprintf (outf, " )\n"); +} + +/* Print the classic direction vector DIRV to OUTF. */ + +void +print_direction_vector (FILE *outf, + lambda_vector dirv, + int length) +{ + int eq; + + for (eq = 0; eq < length; eq++) + { + enum data_dependence_direction dir = 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. */ + +void +print_dir_vectors (FILE *outf, VEC (lambda_vector, heap) *dir_vects, + int length) +{ + unsigned j; + lambda_vector v; + + for (j = 0; VEC_iterate (lambda_vector, dir_vects, j, v); j++) + print_direction_vector (outf, v, length); +} + +/* Print a vector of distance vectors. */ + +void +print_dist_vectors (FILE *outf, VEC (lambda_vector, heap) *dist_vects, + int length) +{ + unsigned j; + lambda_vector v; + + for (j = 0; VEC_iterate (lambda_vector, dist_vects, j, v); j++) + print_lambda_vector (outf, v, length); +} + +/* Debug version. */ + +void +debug_data_dependence_relation (struct data_dependence_relation *ddr) +{ + dump_data_dependence_relation (stderr, ddr); +} + +/* Dump function for a DATA_DEPENDENCE_RELATION structure. */ + +void +dump_data_dependence_relation (FILE *outf, + struct data_dependence_relation *ddr) +{ + struct data_reference *dra, *drb; + + dra = DDR_A (ddr); + drb = DDR_B (ddr); + fprintf (outf, "(Data Dep: \n"); + if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) + fprintf (outf, " (don't know)\n"); + + else if (DDR_ARE_DEPENDENT (ddr) == chrec_known) + fprintf (outf, " (no dependence)\n"); + + else if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) + { + unsigned int i; + struct loop *loopi; + + for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) + { + fprintf (outf, " access_fn_A: "); + print_generic_stmt (outf, DR_ACCESS_FN (dra, i), 0); + fprintf (outf, " access_fn_B: "); + print_generic_stmt (outf, DR_ACCESS_FN (drb, i), 0); + dump_subscript (outf, DDR_SUBSCRIPT (ddr, i)); + } + + fprintf (outf, " loop nest: ("); + for (i = 0; VEC_iterate (loop_p, DDR_LOOP_NEST (ddr), i, loopi); i++) + 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"); +} + +/* Dump function for a DATA_DEPENDENCE_DIRECTION structure. */ + +void +dump_data_dependence_direction (FILE *file, + enum data_dependence_direction dir) +{ + switch (dir) + { + case dir_positive: + fprintf (file, "+"); + break; + + case dir_negative: + fprintf (file, "-"); + break; + + case dir_equal: + fprintf (file, "="); + break; + + case dir_positive_or_negative: + fprintf (file, "+-"); + break; + + case dir_positive_or_equal: + fprintf (file, "+="); + break; + + case dir_negative_or_equal: + fprintf (file, "-="); + break; + + case dir_star: + fprintf (file, "*"); + break; + + default: + break; + } +} + +/* 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. */ + +void +dump_dist_dir_vectors (FILE *file, VEC (ddr_p, heap) *ddrs) +{ + unsigned int i, j; + struct data_dependence_relation *ddr; + lambda_vector v; + + for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++) + if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE && DDR_AFFINE_P (ddr)) + { + for (j = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), j, v); j++) + { + fprintf (file, "DISTANCE_V ("); + print_lambda_vector (file, v, DDR_NB_LOOPS (ddr)); + fprintf (file, ")\n"); + } + + for (j = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), j, v); j++) + { + 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. */ + +void +dump_ddrs (FILE *file, VEC (ddr_p, heap) *ddrs) +{ + unsigned int i; + struct data_dependence_relation *ddr; + + for (i = 0; VEC_iterate (ddr_p, ddrs, i, ddr); i++) + dump_data_dependence_relation (file, ddr); + + fprintf (file, "\n\n"); +} + + + +/* Estimate the number of iterations from the size of the data and the + access functions. */ + +static void +estimate_niter_from_size_of_data (struct loop *loop, + tree opnd0, + tree access_fn, + tree stmt) +{ + tree estimation = NULL_TREE; + tree array_size, data_size, element_size; + tree init, step; + + init = initial_condition (access_fn); + step = evolution_part_in_loop_num (access_fn, loop->num); + + array_size = TYPE_SIZE (TREE_TYPE (opnd0)); + element_size = TYPE_SIZE (TREE_TYPE (TREE_TYPE (opnd0))); + if (array_size == NULL_TREE + || TREE_CODE (array_size) != INTEGER_CST + || TREE_CODE (element_size) != INTEGER_CST) + return; + + data_size = fold_build2 (EXACT_DIV_EXPR, integer_type_node, + array_size, element_size); + + if (init != NULL_TREE + && step != NULL_TREE + && TREE_CODE (init) == INTEGER_CST + && TREE_CODE (step) == INTEGER_CST) + { + tree i_plus_s = fold_build2 (PLUS_EXPR, integer_type_node, init, step); + tree sign = fold_binary (GT_EXPR, boolean_type_node, i_plus_s, init); + + if (sign == boolean_true_node) + estimation = fold_build2 (CEIL_DIV_EXPR, integer_type_node, + fold_build2 (MINUS_EXPR, integer_type_node, + data_size, init), step); + + /* When the step is negative, as in PR23386: (init = 3, step = + 0ffffffff, data_size = 100), we have to compute the + estimation as ceil_div (init, 0 - step) + 1. */ + else if (sign == boolean_false_node) + estimation = + fold_build2 (PLUS_EXPR, integer_type_node, + fold_build2 (CEIL_DIV_EXPR, integer_type_node, + init, + fold_build2 (MINUS_EXPR, unsigned_type_node, + integer_zero_node, step)), + integer_one_node); + + if (estimation) + record_estimate (loop, estimation, boolean_true_node, stmt); + } +} + +/* Given an ARRAY_REF node REF, records its access functions. + Example: given A[i][3], record in ACCESS_FNS the opnd1 function, + i.e. the constant "3", then recursively call the function on opnd0, + i.e. the ARRAY_REF "A[i]". + If ESTIMATE_ONLY is true, we just set the estimated number of loop + iterations, we don't store the access function. + The function returns the base name: "A". */ + +static tree +analyze_array_indexes (struct loop *loop, + VEC(tree,heap) **access_fns, + tree ref, tree stmt, + bool estimate_only) +{ + tree opnd0, opnd1; + tree access_fn; + + opnd0 = TREE_OPERAND (ref, 0); + opnd1 = TREE_OPERAND (ref, 1); + + /* The detection of the evolution function for this data access is + postponed until the dependence test. This lazy strategy avoids + the computation of access functions that are of no interest for + the optimizers. */ + access_fn = instantiate_parameters + (loop, analyze_scalar_evolution (loop, opnd1)); + + if (estimate_only + && chrec_contains_undetermined (loop->estimated_nb_iterations)) + estimate_niter_from_size_of_data (loop, opnd0, access_fn, stmt); + + if (!estimate_only) + VEC_safe_push (tree, heap, *access_fns, access_fn); + + /* Recursively record other array access functions. */ + if (TREE_CODE (opnd0) == ARRAY_REF) + return analyze_array_indexes (loop, access_fns, opnd0, stmt, estimate_only); + + /* Return the base name of the data access. */ + else + return opnd0; +} + +/* For an array reference REF contained in STMT, attempt to bound the + number of iterations in the loop containing STMT */ + +void +estimate_iters_using_array (tree stmt, tree ref) +{ + analyze_array_indexes (loop_containing_stmt (stmt), NULL, ref, stmt, + true); +} + +/* For a data reference REF contained in the statement STMT, initialize + a DATA_REFERENCE structure, and return it. IS_READ flag has to be + set to true when REF is in the right hand side of an + assignment. */ + +struct data_reference * +analyze_array (tree stmt, tree ref, bool is_read) +{ + struct data_reference *res; + VEC(tree,heap) *acc_fns; + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "(analyze_array \n"); + fprintf (dump_file, " (ref = "); + print_generic_stmt (dump_file, ref, 0); + fprintf (dump_file, ")\n"); + } + + res = XNEW (struct data_reference); + + DR_STMT (res) = stmt; + DR_REF (res) = ref; + acc_fns = VEC_alloc (tree, heap, 3); + DR_BASE_OBJECT (res) = analyze_array_indexes + (loop_containing_stmt (stmt), &acc_fns, ref, stmt, false); + DR_TYPE (res) = ARRAY_REF_TYPE; + DR_SET_ACCESS_FNS (res, acc_fns); + DR_IS_READ (res) = is_read; + DR_BASE_ADDRESS (res) = NULL_TREE; + DR_OFFSET (res) = NULL_TREE; + DR_INIT (res) = NULL_TREE; + DR_STEP (res) = NULL_TREE; + DR_OFFSET_MISALIGNMENT (res) = NULL_TREE; + DR_MEMTAG (res) = NULL_TREE; + DR_PTR_INFO (res) = NULL; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ")\n"); + + return res; +} + +/* Analyze an indirect memory reference, REF, that comes from STMT. + IS_READ is true if this is an indirect load, and false if it is + an indirect store. + Return a new data reference structure representing the indirect_ref, or + NULL if we cannot describe the access function. */ + +static struct data_reference * +analyze_indirect_ref (tree stmt, tree ref, bool is_read) +{ + struct loop *loop = loop_containing_stmt (stmt); + tree ptr_ref = TREE_OPERAND (ref, 0); + tree access_fn = analyze_scalar_evolution (loop, ptr_ref); + tree init = initial_condition_in_loop_num (access_fn, loop->num); + tree base_address = NULL_TREE, evolution, step = NULL_TREE; + struct ptr_info_def *ptr_info = NULL; + + if (TREE_CODE (ptr_ref) == SSA_NAME) + ptr_info = SSA_NAME_PTR_INFO (ptr_ref); + + STRIP_NOPS (init); + if (access_fn == chrec_dont_know || !init || init == chrec_dont_know) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nBad access function of ptr: "); + print_generic_expr (dump_file, ref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nAccess function of ptr: "); + print_generic_expr (dump_file, access_fn, TDF_SLIM); + fprintf (dump_file, "\n"); + } + + if (!expr_invariant_in_loop_p (loop, init)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\ninitial condition is not loop invariant.\n"); + } + else + { + base_address = init; + evolution = evolution_part_in_loop_num (access_fn, loop->num); + if (evolution != chrec_dont_know) + { + if (!evolution) + step = ssize_int (0); + else + { + if (TREE_CODE (evolution) == INTEGER_CST) + step = fold_convert (ssizetype, evolution); + else + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\nnon constant step for ptr access.\n"); + } + } + else + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\nunknown evolution of ptr.\n"); + } + return init_data_ref (stmt, ref, NULL_TREE, access_fn, is_read, base_address, + NULL_TREE, step, NULL_TREE, NULL_TREE, + ptr_info, POINTER_REF_TYPE); +} + +/* For a data reference REF contained in the statement STMT, initialize + a DATA_REFERENCE structure, and return it. */ + +struct data_reference * +init_data_ref (tree stmt, + tree ref, + tree base, + tree access_fn, + bool is_read, + tree base_address, + tree init_offset, + tree step, + tree misalign, + tree memtag, + struct ptr_info_def *ptr_info, + enum data_ref_type type) +{ + struct data_reference *res; + VEC(tree,heap) *acc_fns; + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "(init_data_ref \n"); + fprintf (dump_file, " (ref = "); + print_generic_stmt (dump_file, ref, 0); + fprintf (dump_file, ")\n"); + } + + res = XNEW (struct data_reference); + + DR_STMT (res) = stmt; + DR_REF (res) = ref; + DR_BASE_OBJECT (res) = base; + DR_TYPE (res) = type; + acc_fns = VEC_alloc (tree, heap, 3); + DR_SET_ACCESS_FNS (res, acc_fns); + VEC_quick_push (tree, DR_ACCESS_FNS (res), access_fn); + DR_IS_READ (res) = is_read; + DR_BASE_ADDRESS (res) = base_address; + DR_OFFSET (res) = init_offset; + DR_INIT (res) = NULL_TREE; + DR_STEP (res) = step; + DR_OFFSET_MISALIGNMENT (res) = misalign; + DR_MEMTAG (res) = memtag; + DR_PTR_INFO (res) = ptr_info; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ")\n"); + + return res; +} + +/* Function strip_conversions + + Strip conversions that don't narrow the mode. */ + +static tree +strip_conversion (tree expr) +{ + tree to, ti, oprnd0; + + while (TREE_CODE (expr) == NOP_EXPR || TREE_CODE (expr) == CONVERT_EXPR) + { + to = TREE_TYPE (expr); + oprnd0 = TREE_OPERAND (expr, 0); + ti = TREE_TYPE (oprnd0); + + if (!INTEGRAL_TYPE_P (to) || !INTEGRAL_TYPE_P (ti)) + return NULL_TREE; + if (GET_MODE_SIZE (TYPE_MODE (to)) < GET_MODE_SIZE (TYPE_MODE (ti))) + return NULL_TREE; + + expr = oprnd0; + } + return expr; +} + + +/* Function analyze_offset_expr + + Given an offset expression EXPR received from get_inner_reference, analyze + it and create an expression for INITIAL_OFFSET by substituting the variables + of EXPR with initial_condition of the corresponding access_fn in the loop. + E.g., + for i + for (j = 3; j < N; j++) + a[j].b[i][j] = 0; + + For a[j].b[i][j], EXPR will be 'i * C_i + j * C_j + C'. 'i' cannot be + substituted, since its access_fn in the inner loop is i. 'j' will be + substituted with 3. An INITIAL_OFFSET will be 'i * C_i + C`', where + C` = 3 * C_j + C. + + Compute MISALIGN (the misalignment of the data reference initial access from + its base). Misalignment can be calculated only if all the variables can be + substituted with constants, otherwise, we record maximum possible alignment + in ALIGNED_TO. In the above example, since 'i' cannot be substituted, MISALIGN + will be NULL_TREE, and the biggest divider of C_i (a power of 2) will be + recorded in ALIGNED_TO. + + STEP is an evolution of the data reference in this loop in bytes. + In the above example, STEP is C_j. + + Return FALSE, if the analysis fails, e.g., there is no access_fn for a + variable. In this case, all the outputs (INITIAL_OFFSET, MISALIGN, ALIGNED_TO + and STEP) are NULL_TREEs. Otherwise, return TRUE. + +*/ + +static bool +analyze_offset_expr (tree expr, + struct loop *loop, + tree *initial_offset, + tree *misalign, + tree *aligned_to, + tree *step) +{ + tree oprnd0; + tree oprnd1; + tree left_offset = ssize_int (0); + tree right_offset = ssize_int (0); + tree left_misalign = ssize_int (0); + tree right_misalign = ssize_int (0); + tree left_step = ssize_int (0); + tree right_step = ssize_int (0); + enum tree_code code; + tree init, evolution; + tree left_aligned_to = NULL_TREE, right_aligned_to = NULL_TREE; + + *step = NULL_TREE; + *misalign = NULL_TREE; + *aligned_to = NULL_TREE; + *initial_offset = NULL_TREE; + + /* Strip conversions that don't narrow the mode. */ + expr = strip_conversion (expr); + if (!expr) + return false; + + /* Stop conditions: + 1. Constant. */ + if (TREE_CODE (expr) == INTEGER_CST) + { + *initial_offset = fold_convert (ssizetype, expr); + *misalign = fold_convert (ssizetype, expr); + *step = ssize_int (0); + return true; + } + + /* 2. Variable. Try to substitute with initial_condition of the corresponding + access_fn in the current loop. */ + if (SSA_VAR_P (expr)) + { + tree access_fn = analyze_scalar_evolution (loop, expr); + + if (access_fn == chrec_dont_know) + /* No access_fn. */ + return false; + + init = initial_condition_in_loop_num (access_fn, loop->num); + if (!expr_invariant_in_loop_p (loop, init)) + /* Not enough information: may be not loop invariant. + E.g., for a[b[i]], we get a[D], where D=b[i]. EXPR is D, its + initial_condition is D, but it depends on i - loop's induction + variable. */ + return false; + + evolution = evolution_part_in_loop_num (access_fn, loop->num); + if (evolution && TREE_CODE (evolution) != INTEGER_CST) + /* Evolution is not constant. */ + return false; + + if (TREE_CODE (init) == INTEGER_CST) + *misalign = fold_convert (ssizetype, init); + else + /* Not constant, misalignment cannot be calculated. */ + *misalign = NULL_TREE; + + *initial_offset = fold_convert (ssizetype, init); + + *step = evolution ? fold_convert (ssizetype, evolution) : ssize_int (0); + return true; + } + + /* Recursive computation. */ + if (!BINARY_CLASS_P (expr)) + { + /* We expect to get binary expressions (PLUS/MINUS and MULT). */ + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nNot binary expression "); + print_generic_expr (dump_file, expr, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return false; + } + oprnd0 = TREE_OPERAND (expr, 0); + oprnd1 = TREE_OPERAND (expr, 1); + + if (!analyze_offset_expr (oprnd0, loop, &left_offset, &left_misalign, + &left_aligned_to, &left_step) + || !analyze_offset_expr (oprnd1, loop, &right_offset, &right_misalign, + &right_aligned_to, &right_step)) + return false; + + /* The type of the operation: plus, minus or mult. */ + code = TREE_CODE (expr); + switch (code) + { + case MULT_EXPR: + if (TREE_CODE (right_offset) != INTEGER_CST) + /* RIGHT_OFFSET can be not constant. For example, for arrays of variable + sized types. + FORNOW: We don't support such cases. */ + return false; + + /* Strip conversions that don't narrow the mode. */ + left_offset = strip_conversion (left_offset); + if (!left_offset) + return false; + /* Misalignment computation. */ + if (SSA_VAR_P (left_offset)) + { + /* If the left side contains variables that can't be substituted with + constants, the misalignment is unknown. However, if the right side + is a multiple of some alignment, we know that the expression is + aligned to it. Therefore, we record such maximum possible value. + */ + *misalign = NULL_TREE; + *aligned_to = ssize_int (highest_pow2_factor (right_offset)); + } + else + { + /* The left operand was successfully substituted with constant. */ + if (left_misalign) + { + /* In case of EXPR '(i * C1 + j) * C2', LEFT_MISALIGN is + NULL_TREE. */ + *misalign = size_binop (code, left_misalign, right_misalign); + if (left_aligned_to && right_aligned_to) + *aligned_to = size_binop (MIN_EXPR, left_aligned_to, + right_aligned_to); + else + *aligned_to = left_aligned_to ? + left_aligned_to : right_aligned_to; + } + else + *misalign = NULL_TREE; + } + + /* Step calculation. */ + /* Multiply the step by the right operand. */ + *step = size_binop (MULT_EXPR, left_step, right_offset); + break; + + case PLUS_EXPR: + case MINUS_EXPR: + /* Combine the recursive calculations for step and misalignment. */ + *step = size_binop (code, left_step, right_step); + + /* Unknown alignment. */ + if ((!left_misalign && !left_aligned_to) + || (!right_misalign && !right_aligned_to)) + { + *misalign = NULL_TREE; + *aligned_to = NULL_TREE; + break; + } + + if (left_misalign && right_misalign) + *misalign = size_binop (code, left_misalign, right_misalign); + else + *misalign = left_misalign ? left_misalign : right_misalign; + + if (left_aligned_to && right_aligned_to) + *aligned_to = size_binop (MIN_EXPR, left_aligned_to, right_aligned_to); + else + *aligned_to = left_aligned_to ? left_aligned_to : right_aligned_to; + + break; + + default: + gcc_unreachable (); + } + + /* Compute offset. */ + *initial_offset = fold_convert (ssizetype, + fold_build2 (code, TREE_TYPE (left_offset), + left_offset, + right_offset)); + return true; +} + +/* Function address_analysis + + Return the BASE of the address expression EXPR. + Also compute the OFFSET from BASE, MISALIGN and STEP. + + Input: + EXPR - the address expression that is being analyzed + STMT - the statement that contains EXPR or its original memory reference + IS_READ - TRUE if STMT reads from EXPR, FALSE if writes to EXPR + DR - data_reference struct for the original memory reference + + Output: + BASE (returned value) - the base of the data reference EXPR. + INITIAL_OFFSET - initial offset of EXPR from BASE (an expression) + MISALIGN - offset of EXPR from BASE in bytes (a constant) or NULL_TREE if the + computation is impossible + ALIGNED_TO - maximum alignment of EXPR or NULL_TREE if MISALIGN can be + calculated (doesn't depend on variables) + STEP - evolution of EXPR in the loop + + If something unexpected is encountered (an unsupported form of data-ref), + then NULL_TREE is returned. + */ + +static tree +address_analysis (tree expr, tree stmt, bool is_read, struct data_reference *dr, + tree *offset, tree *misalign, tree *aligned_to, tree *step) +{ + tree oprnd0, oprnd1, base_address, offset_expr, base_addr0, base_addr1; + tree address_offset = ssize_int (0), address_misalign = ssize_int (0); + tree dummy, address_aligned_to = NULL_TREE; + struct ptr_info_def *dummy1; + subvar_t dummy2; + + switch (TREE_CODE (expr)) + { + case PLUS_EXPR: + case MINUS_EXPR: + /* EXPR is of form {base +/- offset} (or {offset +/- base}). */ + oprnd0 = TREE_OPERAND (expr, 0); + oprnd1 = TREE_OPERAND (expr, 1); + + STRIP_NOPS (oprnd0); + STRIP_NOPS (oprnd1); + + /* Recursively try to find the base of the address contained in EXPR. + For offset, the returned base will be NULL. */ + base_addr0 = address_analysis (oprnd0, stmt, is_read, dr, &address_offset, + &address_misalign, &address_aligned_to, + step); + + base_addr1 = address_analysis (oprnd1, stmt, is_read, dr, &address_offset, + &address_misalign, &address_aligned_to, + step); + + /* We support cases where only one of the operands contains an + address. */ + if ((base_addr0 && base_addr1) || (!base_addr0 && !base_addr1)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, + "\neither more than one address or no addresses in expr "); + print_generic_expr (dump_file, expr, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + /* To revert STRIP_NOPS. */ + oprnd0 = TREE_OPERAND (expr, 0); + oprnd1 = TREE_OPERAND (expr, 1); + + offset_expr = base_addr0 ? + fold_convert (ssizetype, oprnd1) : fold_convert (ssizetype, oprnd0); + + /* EXPR is of form {base +/- offset} (or {offset +/- base}). If offset is + a number, we can add it to the misalignment value calculated for base, + otherwise, misalignment is NULL. */ + if (TREE_CODE (offset_expr) == INTEGER_CST && address_misalign) + { + *misalign = size_binop (TREE_CODE (expr), address_misalign, + offset_expr); + *aligned_to = address_aligned_to; + } + else + { + *misalign = NULL_TREE; + *aligned_to = NULL_TREE; + } + + /* Combine offset (from EXPR {base + offset}) with the offset calculated + for base. */ + *offset = size_binop (TREE_CODE (expr), address_offset, offset_expr); + return base_addr0 ? base_addr0 : base_addr1; + + case ADDR_EXPR: + base_address = object_analysis (TREE_OPERAND (expr, 0), stmt, is_read, + &dr, offset, misalign, aligned_to, step, + &dummy, &dummy1, &dummy2); + return base_address; + + case SSA_NAME: + if (!POINTER_TYPE_P (TREE_TYPE (expr))) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nnot pointer SSA_NAME "); + print_generic_expr (dump_file, expr, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + *aligned_to = ssize_int (TYPE_ALIGN_UNIT (TREE_TYPE (TREE_TYPE (expr)))); + *misalign = ssize_int (0); + *offset = ssize_int (0); + *step = ssize_int (0); + return expr; + + default: + return NULL_TREE; + } +} + + +/* Function object_analysis + + Create a data-reference structure DR for MEMREF. + Return the BASE of the data reference MEMREF if the analysis is possible. + Also compute the INITIAL_OFFSET from BASE, MISALIGN and STEP. + E.g., for EXPR a.b[i] + 4B, BASE is a, and OFFSET is the overall offset + 'a.b[i] + 4B' from a (can be an expression), MISALIGN is an OFFSET + instantiated with initial_conditions of access_functions of variables, + and STEP is the evolution of the DR_REF in this loop. + + Function get_inner_reference is used for the above in case of ARRAY_REF and + COMPONENT_REF. + + The structure of the function is as follows: + Part 1: + Case 1. For handled_component_p refs + 1.1 build data-reference structure for MEMREF + 1.2 call get_inner_reference + 1.2.1 analyze offset expr received from get_inner_reference + (fall through with BASE) + Case 2. For declarations + 2.1 set MEMTAG + Case 3. For INDIRECT_REFs + 3.1 build data-reference structure for MEMREF + 3.2 analyze evolution and initial condition of MEMREF + 3.3 set data-reference structure for MEMREF + 3.4 call address_analysis to analyze INIT of the access function + 3.5 extract memory tag + + Part 2: + Combine the results of object and address analysis to calculate + INITIAL_OFFSET, STEP and misalignment info. + + Input: + MEMREF - the memory reference that is being analyzed + STMT - the statement that contains MEMREF + IS_READ - TRUE if STMT reads from MEMREF, FALSE if writes to MEMREF + + Output: + BASE_ADDRESS (returned value) - the base address of the data reference MEMREF + E.g, if MEMREF is a.b[k].c[i][j] the returned + base is &a. + DR - data_reference struct for MEMREF + INITIAL_OFFSET - initial offset of MEMREF from BASE (an expression) + MISALIGN - offset of MEMREF from BASE in bytes (a constant) modulo alignment of + ALIGNMENT or NULL_TREE if the computation is impossible + ALIGNED_TO - maximum alignment of EXPR or NULL_TREE if MISALIGN can be + calculated (doesn't depend on variables) + STEP - evolution of the DR_REF in the loop + MEMTAG - memory tag for aliasing purposes + PTR_INFO - NULL or points-to aliasing info from a pointer SSA_NAME + SUBVARS - Sub-variables of the variable + + If the analysis of MEMREF evolution in the loop fails, NULL_TREE is returned, + but DR can be created anyway. + +*/ + +static tree +object_analysis (tree memref, tree stmt, bool is_read, + struct data_reference **dr, tree *offset, tree *misalign, + tree *aligned_to, tree *step, tree *memtag, + struct ptr_info_def **ptr_info, subvar_t *subvars) +{ + tree base = NULL_TREE, base_address = NULL_TREE; + tree object_offset = ssize_int (0), object_misalign = ssize_int (0); + tree object_step = ssize_int (0), address_step = ssize_int (0); + tree address_offset = ssize_int (0), address_misalign = ssize_int (0); + HOST_WIDE_INT pbitsize, pbitpos; + tree poffset, bit_pos_in_bytes; + enum machine_mode pmode; + int punsignedp, pvolatilep; + tree ptr_step = ssize_int (0), ptr_init = NULL_TREE; + struct loop *loop = loop_containing_stmt (stmt); + struct data_reference *ptr_dr = NULL; + tree object_aligned_to = NULL_TREE, address_aligned_to = NULL_TREE; + tree comp_ref = NULL_TREE; + + *ptr_info = NULL; + + /* Part 1: */ + /* Case 1. handled_component_p refs. */ + if (handled_component_p (memref)) + { + /* 1.1 build data-reference structure for MEMREF. */ + if (!(*dr)) + { + if (TREE_CODE (memref) == ARRAY_REF) + *dr = analyze_array (stmt, memref, is_read); + else if (TREE_CODE (memref) == COMPONENT_REF) + comp_ref = memref; + else + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\ndata-ref of unsupported type "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + } + + /* 1.2 call get_inner_reference. */ + /* Find the base and the offset from it. */ + base = get_inner_reference (memref, &pbitsize, &pbitpos, &poffset, + &pmode, &punsignedp, &pvolatilep, false); + if (!base) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nfailed to get inner ref for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + /* 1.2.1 analyze offset expr received from get_inner_reference. */ + if (poffset + && !analyze_offset_expr (poffset, loop, &object_offset, + &object_misalign, &object_aligned_to, + &object_step)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nfailed to compute offset or step for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + /* Add bit position to OFFSET and MISALIGN. */ + + bit_pos_in_bytes = ssize_int (pbitpos/BITS_PER_UNIT); + /* Check that there is no remainder in bits. */ + if (pbitpos%BITS_PER_UNIT) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\nbit offset alignment.\n"); + return NULL_TREE; + } + object_offset = size_binop (PLUS_EXPR, bit_pos_in_bytes, object_offset); + if (object_misalign) + object_misalign = size_binop (PLUS_EXPR, object_misalign, + bit_pos_in_bytes); + + memref = base; /* To continue analysis of BASE. */ + /* fall through */ + } + + /* Part 1: Case 2. Declarations. */ + if (DECL_P (memref)) + { + /* We expect to get a decl only if we already have a DR, or with + COMPONENT_REFs of type 'a[i].b'. */ + if (!(*dr)) + { + if (comp_ref && TREE_CODE (TREE_OPERAND (comp_ref, 0)) == ARRAY_REF) + { + *dr = analyze_array (stmt, TREE_OPERAND (comp_ref, 0), is_read); + if (DR_NUM_DIMENSIONS (*dr) != 1) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\n multidimensional component ref "); + print_generic_expr (dump_file, comp_ref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + } + else + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nunhandled decl "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + } + + /* TODO: if during the analysis of INDIRECT_REF we get to an object, put + the object in BASE_OBJECT field if we can prove that this is O.K., + i.e., the data-ref access is bounded by the bounds of the BASE_OBJECT. + (e.g., if the object is an array base 'a', where 'a[N]', we must prove + that every access with 'p' (the original INDIRECT_REF based on '&a') + in the loop is within the array boundaries - from a[0] to a[N-1]). + Otherwise, our alias analysis can be incorrect. + Even if an access function based on BASE_OBJECT can't be build, update + BASE_OBJECT field to enable us to prove that two data-refs are + different (without access function, distance analysis is impossible). + */ + if (SSA_VAR_P (memref) && var_can_have_subvars (memref)) + *subvars = get_subvars_for_var (memref); + base_address = build_fold_addr_expr (memref); + /* 2.1 set MEMTAG. */ + *memtag = memref; + } + + /* Part 1: Case 3. INDIRECT_REFs. */ + else if (TREE_CODE (memref) == INDIRECT_REF) + { + tree ptr_ref = TREE_OPERAND (memref, 0); + if (TREE_CODE (ptr_ref) == SSA_NAME) + *ptr_info = SSA_NAME_PTR_INFO (ptr_ref); + + /* 3.1 build data-reference structure for MEMREF. */ + ptr_dr = analyze_indirect_ref (stmt, memref, is_read); + if (!ptr_dr) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nfailed to create dr for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + /* 3.2 analyze evolution and initial condition of MEMREF. */ + ptr_step = DR_STEP (ptr_dr); + ptr_init = DR_BASE_ADDRESS (ptr_dr); + if (!ptr_init || !ptr_step || !POINTER_TYPE_P (TREE_TYPE (ptr_init))) + { + *dr = (*dr) ? *dr : ptr_dr; + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nbad pointer access "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + if (integer_zerop (ptr_step) && !(*dr)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "\nptr is loop invariant.\n"); + *dr = ptr_dr; + return NULL_TREE; + + /* If there exists DR for MEMREF, we are analyzing the base of + handled component (PTR_INIT), which not necessary has evolution in + the loop. */ + } + object_step = size_binop (PLUS_EXPR, object_step, ptr_step); + + /* 3.3 set data-reference structure for MEMREF. */ + if (!*dr) + *dr = ptr_dr; + + /* 3.4 call address_analysis to analyze INIT of the access + function. */ + base_address = address_analysis (ptr_init, stmt, is_read, *dr, + &address_offset, &address_misalign, + &address_aligned_to, &address_step); + if (!base_address) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nfailed to analyze address "); + print_generic_expr (dump_file, ptr_init, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + /* 3.5 extract memory tag. */ + switch (TREE_CODE (base_address)) + { + case SSA_NAME: + *memtag = get_var_ann (SSA_NAME_VAR (base_address))->symbol_mem_tag; + if (!(*memtag) && TREE_CODE (TREE_OPERAND (memref, 0)) == SSA_NAME) + *memtag = get_var_ann ( + SSA_NAME_VAR (TREE_OPERAND (memref, 0)))->symbol_mem_tag; + break; + case ADDR_EXPR: + *memtag = TREE_OPERAND (base_address, 0); + break; + default: + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nno memtag for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + *memtag = NULL_TREE; + break; + } + } + + if (!base_address) + { + /* MEMREF cannot be analyzed. */ + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\ndata-ref of unsupported type "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL_TREE; + } + + if (comp_ref) + DR_REF (*dr) = comp_ref; + + if (SSA_VAR_P (*memtag) && var_can_have_subvars (*memtag)) + *subvars = get_subvars_for_var (*memtag); + + /* Part 2: Combine the results of object and address analysis to calculate + INITIAL_OFFSET, STEP and misalignment info. */ + *offset = size_binop (PLUS_EXPR, object_offset, address_offset); + + if ((!object_misalign && !object_aligned_to) + || (!address_misalign && !address_aligned_to)) + { + *misalign = NULL_TREE; + *aligned_to = NULL_TREE; + } + else + { + if (object_misalign && address_misalign) + *misalign = size_binop (PLUS_EXPR, object_misalign, address_misalign); + else + *misalign = object_misalign ? object_misalign : address_misalign; + if (object_aligned_to && address_aligned_to) + *aligned_to = size_binop (MIN_EXPR, object_aligned_to, + address_aligned_to); + else + *aligned_to = object_aligned_to ? + object_aligned_to : address_aligned_to; + } + *step = size_binop (PLUS_EXPR, object_step, address_step); + + return base_address; +} + +/* Function analyze_offset. + + Extract INVARIANT and CONSTANT parts from OFFSET. + +*/ +static bool +analyze_offset (tree offset, tree *invariant, tree *constant) +{ + tree op0, op1, constant_0, constant_1, invariant_0, invariant_1; + enum tree_code code = TREE_CODE (offset); + + *invariant = NULL_TREE; + *constant = NULL_TREE; + + /* Not PLUS/MINUS expression - recursion stop condition. */ + if (code != PLUS_EXPR && code != MINUS_EXPR) + { + if (TREE_CODE (offset) == INTEGER_CST) + *constant = offset; + else + *invariant = offset; + return true; + } + + op0 = TREE_OPERAND (offset, 0); + op1 = TREE_OPERAND (offset, 1); + + /* Recursive call with the operands. */ + if (!analyze_offset (op0, &invariant_0, &constant_0) + || !analyze_offset (op1, &invariant_1, &constant_1)) + return false; + + /* Combine the results. Add negation to the subtrahend in case of + subtraction. */ + if (constant_0 && constant_1) + return false; + *constant = constant_0 ? constant_0 : constant_1; + if (code == MINUS_EXPR && constant_1) + *constant = fold_build1 (NEGATE_EXPR, TREE_TYPE (*constant), *constant); + + if (invariant_0 && invariant_1) + *invariant = + fold_build2 (code, TREE_TYPE (invariant_0), invariant_0, invariant_1); + else + { + *invariant = invariant_0 ? invariant_0 : invariant_1; + if (code == MINUS_EXPR && invariant_1) + *invariant = + fold_build1 (NEGATE_EXPR, TREE_TYPE (*invariant), *invariant); + } + return true; +} + +/* Free the memory used by the data reference DR. */ + +static void +free_data_ref (data_reference_p dr) +{ + DR_FREE_ACCESS_FNS (dr); + free (dr); +} + +/* Function create_data_ref. + + Create a data-reference structure for MEMREF. Set its DR_BASE_ADDRESS, + DR_OFFSET, DR_INIT, DR_STEP, DR_OFFSET_MISALIGNMENT, DR_ALIGNED_TO, + DR_MEMTAG, and DR_POINTSTO_INFO fields. + + Input: + MEMREF - the memory reference that is being analyzed + STMT - the statement that contains MEMREF + IS_READ - TRUE if STMT reads from MEMREF, FALSE if writes to MEMREF + + Output: + DR (returned value) - data_reference struct for MEMREF +*/ + +static struct data_reference * +create_data_ref (tree memref, tree stmt, bool is_read) +{ + struct data_reference *dr = NULL; + tree base_address, offset, step, misalign, memtag; + struct loop *loop = loop_containing_stmt (stmt); + tree invariant = NULL_TREE, constant = NULL_TREE; + tree type_size, init_cond; + struct ptr_info_def *ptr_info; + subvar_t subvars = NULL; + tree aligned_to, type = NULL_TREE, orig_offset; + + if (!memref) + return NULL; + + base_address = object_analysis (memref, stmt, is_read, &dr, &offset, + &misalign, &aligned_to, &step, &memtag, + &ptr_info, &subvars); + if (!dr || !base_address) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\ncreate_data_ref: failed to create a dr for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL; + } + + DR_BASE_ADDRESS (dr) = base_address; + DR_OFFSET (dr) = offset; + DR_INIT (dr) = ssize_int (0); + DR_STEP (dr) = step; + DR_OFFSET_MISALIGNMENT (dr) = misalign; + DR_ALIGNED_TO (dr) = aligned_to; + DR_MEMTAG (dr) = memtag; + DR_PTR_INFO (dr) = ptr_info; + DR_SUBVARS (dr) = subvars; + + type_size = fold_convert (ssizetype, TYPE_SIZE_UNIT (TREE_TYPE (DR_REF (dr)))); + + /* Extract CONSTANT and INVARIANT from OFFSET. */ + /* Remove cast from OFFSET and restore it for INVARIANT part. */ + orig_offset = offset; + STRIP_NOPS (offset); + if (offset != orig_offset) + type = TREE_TYPE (orig_offset); + if (!analyze_offset (offset, &invariant, &constant)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\ncreate_data_ref: failed to analyze dr's"); + fprintf (dump_file, " offset for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n"); + } + return NULL; + } + if (type && invariant) + invariant = fold_convert (type, invariant); + + /* Put CONSTANT part of OFFSET in DR_INIT and INVARIANT in DR_OFFSET field + of DR. */ + if (constant) + { + DR_INIT (dr) = fold_convert (ssizetype, constant); + init_cond = fold_build2 (TRUNC_DIV_EXPR, TREE_TYPE (constant), + constant, type_size); + } + else + DR_INIT (dr) = init_cond = ssize_int (0); + + if (invariant) + DR_OFFSET (dr) = invariant; + else + DR_OFFSET (dr) = ssize_int (0); + + /* Change the access function for INIDIRECT_REFs, according to + DR_BASE_ADDRESS. Analyze OFFSET calculated in object_analysis. OFFSET is + an expression that can contain loop invariant expressions and constants. + We put the constant part in the initial condition of the access function + (for data dependence tests), and in DR_INIT of the data-ref. The loop + invariant part is put in DR_OFFSET. + The evolution part of the access function is STEP calculated in + object_analysis divided by the size of data type. + */ + if (!DR_BASE_OBJECT (dr) + || (TREE_CODE (memref) == COMPONENT_REF && DR_NUM_DIMENSIONS (dr) == 1)) + { + tree access_fn; + tree new_step; + + /* Update access function. */ + access_fn = DR_ACCESS_FN (dr, 0); + if (automatically_generated_chrec_p (access_fn)) + { + free_data_ref (dr); + return NULL; + } + + new_step = size_binop (TRUNC_DIV_EXPR, + fold_convert (ssizetype, step), type_size); + + init_cond = chrec_convert (chrec_type (access_fn), init_cond, stmt); + new_step = chrec_convert (chrec_type (access_fn), new_step, stmt); + if (automatically_generated_chrec_p (init_cond) + || automatically_generated_chrec_p (new_step)) + { + free_data_ref (dr); + return NULL; + } + access_fn = chrec_replace_initial_condition (access_fn, init_cond); + access_fn = reset_evolution_in_loop (loop->num, access_fn, new_step); + + VEC_replace (tree, DR_ACCESS_FNS (dr), 0, access_fn); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + struct ptr_info_def *pi = DR_PTR_INFO (dr); + + fprintf (dump_file, "\nCreated dr for "); + print_generic_expr (dump_file, memref, TDF_SLIM); + fprintf (dump_file, "\n\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\tbase_object: "); + print_generic_expr (dump_file, DR_BASE_OBJECT (dr), TDF_SLIM); + fprintf (dump_file, "\n\tstep: "); + print_generic_expr (dump_file, DR_STEP (dr), TDF_SLIM); + fprintf (dump_file, "B\n\tmisalignment from base: "); + print_generic_expr (dump_file, DR_OFFSET_MISALIGNMENT (dr), TDF_SLIM); + if (DR_OFFSET_MISALIGNMENT (dr)) + fprintf (dump_file, "B"); + if (DR_ALIGNED_TO (dr)) + { + fprintf (dump_file, "\n\taligned to: "); + print_generic_expr (dump_file, DR_ALIGNED_TO (dr), TDF_SLIM); + } + fprintf (dump_file, "\n\tmemtag: "); + print_generic_expr (dump_file, DR_MEMTAG (dr), TDF_SLIM); + fprintf (dump_file, "\n"); + if (pi && pi->name_mem_tag) + { + fprintf (dump_file, "\n\tnametag: "); + print_generic_expr (dump_file, pi->name_mem_tag, TDF_SLIM); + fprintf (dump_file, "\n"); + } + } + return dr; +} + + +/* Returns true when all the functions of a tree_vec CHREC are the + same. */ + +static bool +all_chrecs_equal_p (tree chrec) +{ + int j; + + for (j = 0; j < TREE_VEC_LENGTH (chrec) - 1; j++) + if (!eq_evolutions_p (TREE_VEC_ELT (chrec, j), + TREE_VEC_ELT (chrec, j + 1))) + return false; + + return true; +} + +/* Determine for each subscript in the data dependence relation DDR + the distance. */ + +static void +compute_subscript_distance (struct data_dependence_relation *ddr) +{ + if (DDR_ARE_DEPENDENT (ddr) == NULL_TREE) + { + unsigned int i; + + for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) + { + tree conflicts_a, conflicts_b, difference; + struct subscript *subscript; + + subscript = DDR_SUBSCRIPT (ddr, i); + conflicts_a = SUB_CONFLICTS_IN_A (subscript); + conflicts_b = SUB_CONFLICTS_IN_B (subscript); + + if (TREE_CODE (conflicts_a) == TREE_VEC) + { + if (!all_chrecs_equal_p (conflicts_a)) + { + SUB_DISTANCE (subscript) = chrec_dont_know; + return; + } + else + conflicts_a = TREE_VEC_ELT (conflicts_a, 0); + } + + if (TREE_CODE (conflicts_b) == TREE_VEC) + { + if (!all_chrecs_equal_p (conflicts_b)) + { + SUB_DISTANCE (subscript) = chrec_dont_know; + return; + } + else + conflicts_b = TREE_VEC_ELT (conflicts_b, 0); + } + + conflicts_b = chrec_convert (integer_type_node, conflicts_b, + NULL_TREE); + conflicts_a = chrec_convert (integer_type_node, conflicts_a, + NULL_TREE); + difference = chrec_fold_minus + (integer_type_node, conflicts_b, conflicts_a); + + if (evolution_function_is_constant_p (difference)) + SUB_DISTANCE (subscript) = difference; + + else + SUB_DISTANCE (subscript) = chrec_dont_know; + } + } +} + +/* 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. */ + +static struct data_dependence_relation * +initialize_data_dependence_relation (struct data_reference *a, + struct data_reference *b, + VEC (loop_p, heap) *loop_nest) +{ + struct data_dependence_relation *res; + bool differ_p, known_dependence; + unsigned int i; + + res = XNEW (struct data_dependence_relation); + DDR_A (res) = a; + DDR_B (res) = b; + DDR_LOOP_NEST (res) = NULL; + + if (a == NULL || b == NULL) + { + DDR_ARE_DEPENDENT (res) = chrec_dont_know; + return res; + } + + /* When A and B are arrays and their dimensions differ, we directly + initialize the relation to "there is no dependence": chrec_known. */ + if (DR_BASE_OBJECT (a) && DR_BASE_OBJECT (b) + && DR_NUM_DIMENSIONS (a) != DR_NUM_DIMENSIONS (b)) + { + DDR_ARE_DEPENDENT (res) = chrec_known; + return res; + } + + if (DR_BASE_ADDRESS (a) && DR_BASE_ADDRESS (b)) + known_dependence = base_addr_differ_p (a, b, &differ_p); + else + known_dependence = base_object_differ_p (a, b, &differ_p); + + if (!known_dependence) + { + /* Can't determine whether the data-refs access the same memory + region. */ + DDR_ARE_DEPENDENT (res) = chrec_dont_know; + return res; + } + + if (differ_p) + { + DDR_ARE_DEPENDENT (res) = chrec_known; + return res; + } + + DDR_AFFINE_P (res) = true; + DDR_ARE_DEPENDENT (res) = NULL_TREE; + DDR_SUBSCRIPTS (res) = VEC_alloc (subscript_p, heap, DR_NUM_DIMENSIONS (a)); + DDR_LOOP_NEST (res) = loop_nest; + DDR_DIR_VECTS (res) = NULL; + DDR_DIST_VECTS (res) = NULL; + + for (i = 0; i < DR_NUM_DIMENSIONS (a); i++) + { + struct subscript *subscript; + + subscript = XNEW (struct subscript); + SUB_CONFLICTS_IN_A (subscript) = chrec_dont_know; + SUB_CONFLICTS_IN_B (subscript) = chrec_dont_know; + SUB_LAST_CONFLICT (subscript) = chrec_dont_know; + SUB_DISTANCE (subscript) = chrec_dont_know; + VEC_safe_push (subscript_p, heap, DDR_SUBSCRIPTS (res), subscript); + } + + return res; +} + +/* 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) +{ + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "(dependence classified: "); + print_generic_expr (dump_file, chrec, 0); + fprintf (dump_file, ")\n"); + } + + DDR_ARE_DEPENDENT (ddr) = chrec; + VEC_free (subscript_p, heap, DDR_SUBSCRIPTS (ddr)); +} + +/* 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 (tree chrec_a, + 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 (tree chrec_a, + 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; + + default: + return true; + } + + default: + return true; + } + } + + return false; +} + +/* 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, + tree *overlaps_a, + tree *overlaps_b, + tree *last_conflicts) +{ + tree difference; + dependence_stats.num_ziv++; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "(analyze_ziv_subscript \n"); + + chrec_a = chrec_convert (integer_type_node, chrec_a, NULL_TREE); + chrec_b = chrec_convert (integer_type_node, chrec_b, NULL_TREE); + difference = chrec_fold_minus (integer_type_node, 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 = integer_zero_node; + *overlaps_b = integer_zero_node; + *last_conflicts = chrec_dont_know; + dependence_stats.num_ziv_dependent++; + } + else + { + /* The accesses do not overlap. */ + *overlaps_a = chrec_known; + *overlaps_b = chrec_known; + *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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + dependence_stats.num_ziv_unimplemented++; + break; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ")\n"); +} + +/* Get the real or estimated number of iterations for LOOPNUM, whichever is + available. Return the number of iterations as a tree, or NULL_TREE if + we don't know. */ + +static tree +get_number_of_iters_for_loop (int loopnum) +{ + tree numiter = number_of_iterations_in_loop (current_loops->parray[loopnum]); + + if (TREE_CODE (numiter) != INTEGER_CST) + numiter = current_loops->parray[loopnum]->estimated_nb_iterations; + if (chrec_contains_undetermined (numiter)) + return NULL_TREE; + return numiter; +} + +/* 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, + tree *overlaps_a, + tree *overlaps_b, + tree *last_conflicts) +{ + bool value0, value1, value2; + tree difference; + + chrec_a = chrec_convert (integer_type_node, chrec_a, NULL_TREE); + chrec_b = chrec_convert (integer_type_node, chrec_b, NULL_TREE); + difference = chrec_fold_minus + (integer_type_node, initial_condition (chrec_b), chrec_a); + + 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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + return; + } + else + { + if (value0 == false) + { + if (!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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *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)) + { + tree numiter; + int loopnum = CHREC_VARIABLE (chrec_b); + + *overlaps_a = integer_zero_node; + *overlaps_b = fold_build2 (EXACT_DIV_EXPR, integer_type_node, + fold_build1 (ABS_EXPR, + integer_type_node, + difference), + CHREC_RIGHT (chrec_b)); + *last_conflicts = integer_one_node; + + + /* Perform weak-zero siv test to see if overlap is + outside the loop bounds. */ + numiter = get_number_of_iters_for_loop (loopnum); + + if (numiter != NULL_TREE + && TREE_CODE (*overlaps_b) == INTEGER_CST + && tree_int_cst_lt (numiter, *overlaps_b)) + { + *overlaps_a = chrec_known; + *overlaps_b = chrec_known; + *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 = chrec_known; + *overlaps_b = chrec_known; + *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 = chrec_known; + *overlaps_b = chrec_known; + *last_conflicts = integer_zero_node; + dependence_stats.num_siv_independent++; + return; + } + } + } + else + { + if (!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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *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)) + { + tree numiter; + int loopnum = CHREC_VARIABLE (chrec_b); + + *overlaps_a = integer_zero_node; + *overlaps_b = fold_build2 (EXACT_DIV_EXPR, + integer_type_node, difference, + CHREC_RIGHT (chrec_b)); + *last_conflicts = integer_one_node; + + /* Perform weak-zero siv test to see if overlap is + outside the loop bounds. */ + numiter = get_number_of_iters_for_loop (loopnum); + + if (numiter != NULL_TREE + && TREE_CODE (*overlaps_b) == INTEGER_CST + && tree_int_cst_lt (numiter, *overlaps_b)) + { + *overlaps_a = chrec_known; + *overlaps_b = chrec_known; + *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 = chrec_known; + *overlaps_b = chrec_known; + *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 = chrec_known; + *overlaps_b = chrec_known; + *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 int +initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult) +{ + gcc_assert (chrec); + + if (TREE_CODE (chrec) != POLYNOMIAL_CHREC) + return int_cst_value (chrec); + + A[index][0] = mult * int_cst_value (CHREC_RIGHT (chrec)); + return initialize_matrix_A (A, CHREC_LEFT (chrec), index + 1, mult); +} + +#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 (int niter, int step_a, int step_b, + tree *overlaps_a, tree *overlaps_b, + tree *last_conflicts, int dim) +{ + if (((step_a > 0 && step_b > 0) + || (step_a < 0 && step_b < 0))) + { + int step_overlaps_a, step_overlaps_b; + 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; + + tau2 = FLOOR_DIV (niter, step_overlaps_a); + tau2 = MIN (tau2, FLOOR_DIV (niter, step_overlaps_b)); + last_conflict = tau2; + + *overlaps_a = build_polynomial_chrec + (dim, integer_zero_node, + build_int_cst (NULL_TREE, step_overlaps_a)); + *overlaps_b = build_polynomial_chrec + (dim, integer_zero_node, + build_int_cst (NULL_TREE, step_overlaps_b)); + *last_conflicts = build_int_cst (NULL_TREE, last_conflict); + } + + else + { + *overlaps_a = integer_zero_node; + *overlaps_b = 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, + tree *overlaps_a, tree *overlaps_b, + tree *last_conflicts) +{ + bool xz_p, yz_p, xyz_p; + int step_x, step_y, step_z; + int niter_x, niter_y, niter_z, niter; + tree numiter_x, numiter_y, numiter_z; + tree overlaps_a_xz, overlaps_b_xz, last_conflicts_xz; + tree overlaps_a_yz, overlaps_b_yz, last_conflicts_yz; + tree overlaps_a_xyz, overlaps_b_xyz, 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)); + + numiter_x = get_number_of_iters_for_loop (CHREC_VARIABLE (CHREC_LEFT (chrec_a))); + numiter_y = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_a)); + numiter_z = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_b)); + + if (numiter_x == NULL_TREE || numiter_y == NULL_TREE + || numiter_z == NULL_TREE) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "overlap steps test failed: no iteration counts.\n"); + + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + return; + } + + niter_x = int_cst_value (numiter_x); + niter_y = int_cst_value (numiter_y); + niter_z = int_cst_value (numiter_z); + + 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) + { + *overlaps_a = make_tree_vec (2); + TREE_VEC_ELT (*overlaps_a, 0) = integer_zero_node; + TREE_VEC_ELT (*overlaps_a, 1) = integer_zero_node; + *overlaps_b = integer_zero_node; + if (xz_p) + { + tree t0 = chrec_convert (integer_type_node, + TREE_VEC_ELT (*overlaps_a, 0), NULL_TREE); + tree t1 = chrec_convert (integer_type_node, overlaps_a_xz, + NULL_TREE); + tree t2 = chrec_convert (integer_type_node, *overlaps_b, + NULL_TREE); + tree t3 = chrec_convert (integer_type_node, overlaps_b_xz, + NULL_TREE); + + TREE_VEC_ELT (*overlaps_a, 0) = chrec_fold_plus (integer_type_node, + t0, t1); + *overlaps_b = chrec_fold_plus (integer_type_node, t2, t3); + *last_conflicts = last_conflicts_xz; + } + if (yz_p) + { + tree t0 = chrec_convert (integer_type_node, + TREE_VEC_ELT (*overlaps_a, 1), NULL_TREE); + tree t1 = chrec_convert (integer_type_node, overlaps_a_yz, NULL_TREE); + tree t2 = chrec_convert (integer_type_node, *overlaps_b, NULL_TREE); + tree t3 = chrec_convert (integer_type_node, overlaps_b_yz, NULL_TREE); + + TREE_VEC_ELT (*overlaps_a, 1) = chrec_fold_plus (integer_type_node, + t0, t1); + *overlaps_b = chrec_fold_plus (integer_type_node, t2, t3); + *last_conflicts = last_conflicts_yz; + } + if (xyz_p) + { + tree t0 = chrec_convert (integer_type_node, + TREE_VEC_ELT (*overlaps_a, 0), NULL_TREE); + tree t1 = chrec_convert (integer_type_node, overlaps_a_xyz, + NULL_TREE); + tree t2 = chrec_convert (integer_type_node, + TREE_VEC_ELT (*overlaps_a, 1), NULL_TREE); + tree t3 = chrec_convert (integer_type_node, overlaps_a_xyz, + NULL_TREE); + tree t4 = chrec_convert (integer_type_node, *overlaps_b, NULL_TREE); + tree t5 = chrec_convert (integer_type_node, overlaps_b_xyz, + NULL_TREE); + + TREE_VEC_ELT (*overlaps_a, 0) = chrec_fold_plus (integer_type_node, + t0, t1); + TREE_VEC_ELT (*overlaps_a, 1) = chrec_fold_plus (integer_type_node, + t2, t3); + *overlaps_b = chrec_fold_plus (integer_type_node, t4, t5); + *last_conflicts = last_conflicts_xyz; + } + } + else + { + *overlaps_a = integer_zero_node; + *overlaps_b = integer_zero_node; + *last_conflicts = integer_zero_node; + } +} + +/* 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, + tree *overlaps_a, + tree *overlaps_b, + tree *last_conflicts) +{ + unsigned nb_vars_a, nb_vars_b, dim; + int init_a, init_b, gamma, gcd_alpha_beta; + int tau1, tau2; + lambda_matrix A, U, S; + + if (eq_evolutions_p (chrec_a, chrec_b)) + { + /* The accessed index overlaps for each iteration in the + loop. */ + *overlaps_a = integer_zero_node; + *overlaps_b = 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); + + dim = nb_vars_a + nb_vars_b; + U = lambda_matrix_new (dim, dim); + A = lambda_matrix_new (dim, 1); + S = lambda_matrix_new (dim, 1); + + init_a = initialize_matrix_A (A, chrec_a, 0, 1); + init_b = initialize_matrix_A (A, chrec_b, nb_vars_a, -1); + gamma = init_b - 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) + { + int step_a, step_b; + int niter, niter_a, niter_b; + tree numiter_a, numiter_b; + + numiter_a = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_a)); + numiter_b = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_b)); + if (numiter_a == NULL_TREE || numiter_b == NULL_TREE) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: missing iteration counts.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + goto end_analyze_subs_aa; + } + + niter_a = int_cst_value (numiter_a); + niter_b = int_cst_value (numiter_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, + overlaps_a, overlaps_b, + last_conflicts, 1); + } + + 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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + } + goto end_analyze_subs_aa; + } + + /* U.A = S */ + lambda_matrix_right_hermite (A, dim, 1, S, U); + + 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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *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 = chrec_known; + *overlaps_b = chrec_known; + *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. */ + + int i0, j0, i1, j1; + + /* X0 and Y0 are the first iterations for which there is a + dependence. X0, Y0 are two solutions of the Diophantine + equation: chrec_a (X0) = chrec_b (Y0). */ + int x0, y0; + int niter, niter_a, niter_b; + tree numiter_a, numiter_b; + + numiter_a = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_a)); + numiter_b = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_b)); + + if (numiter_a == NULL_TREE || numiter_b == NULL_TREE) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: missing iteration counts.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + goto end_analyze_subs_aa; + } + + niter_a = int_cst_value (numiter_a); + niter_b = int_cst_value (numiter_b); + niter = MIN (niter_a, niter_b); + + 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 = chrec_known; + *overlaps_b = chrec_known; + *last_conflicts = integer_zero_node; + } + + else + { + if (i1 > 0) + { + tau1 = CEIL (-i0, i1); + tau2 = FLOOR_DIV (niter - i0, i1); + + if (j1 > 0) + { + int last_conflict, min_multiple; + tau1 = MAX (tau1, CEIL (-j0, j1)); + tau2 = MIN (tau2, FLOOR_DIV (niter - j0, j1)); + + x0 = i1 * tau1 + i0; + y0 = j1 * tau1 + j0; + + /* At this point (x0, y0) is one of the + solutions to the Diophantine equation. The + next step has to compute the smallest + positive solution: the first conflicts. */ + min_multiple = MIN (x0 / i1, y0 / j1); + x0 -= i1 * min_multiple; + y0 -= j1 * min_multiple; + + tau1 = (x0 - i0)/i1; + last_conflict = tau2 - tau1; + + /* If the overlap occurs outside of the bounds of the + loop, there is no dependence. */ + if (x0 > niter || y0 > niter) + { + *overlaps_a = chrec_known; + *overlaps_b = chrec_known; + *last_conflicts = integer_zero_node; + } + else + { + *overlaps_a = build_polynomial_chrec + (1, + build_int_cst (NULL_TREE, x0), + build_int_cst (NULL_TREE, i1)); + *overlaps_b = build_polynomial_chrec + (1, + build_int_cst (NULL_TREE, y0), + build_int_cst (NULL_TREE, j1)); + *last_conflicts = build_int_cst (NULL_TREE, last_conflict); + } + } + else + { + /* FIXME: For the moment, the upper bound of the + iteration domain for j is not checked. */ + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + } + } + + else + { + /* FIXME: For the moment, the upper bound of the + iteration domain for i is not checked. */ + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + } + } + } + else + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + } + } + + else + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "affine-affine test failed: unimplemented.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + } + +end_analyze_subs_aa: + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " (overlaps_a = "); + print_generic_expr (dump_file, *overlaps_a, 0); + fprintf (dump_file, ")\n (overlaps_b = "); + print_generic_expr (dump_file, *overlaps_b, 0); + fprintf (dump_file, ")\n"); + 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_TREE); + 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_TREE); + *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, + tree *overlaps_a, + tree *overlaps_b, + tree *last_conflicts) +{ + 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_p (chrec_b)) + analyze_siv_subscript_cst_affine (chrec_a, chrec_b, + overlaps_a, overlaps_b, last_conflicts); + + else if (evolution_function_is_affine_p (chrec_a) + && 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_p (chrec_a) + && evolution_function_is_affine_p (chrec_b)) + { + 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 (*overlaps_a == chrec_dont_know + || *overlaps_b == chrec_dont_know) + dependence_stats.num_siv_unimplemented++; + else if (*overlaps_a == chrec_known + || *overlaps_b == chrec_known) + 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); + /* FIXME: The number of iterations is a symbolic expression. + Compute it properly. */ + *last_conflicts = chrec_dont_know; + + if (*overlaps_a == chrec_dont_know + || *overlaps_b == chrec_dont_know) + dependence_stats.num_siv_unimplemented++; + else if (*overlaps_a == chrec_known + || *overlaps_b == chrec_known) + 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.\n"); + *overlaps_a = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *last_conflicts = chrec_dont_know; + dependence_stats.num_siv_unimplemented++; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ")\n"); +} + +/* Return true when the property can be computed. RES should contain + true when calling the first time this function, then it is set to + false when one of the evolution steps of an affine CHREC does not + divide the constant CST. */ + +static bool +chrec_steps_divide_constant_p (tree chrec, + tree cst, + bool *res) +{ + switch (TREE_CODE (chrec)) + { + case POLYNOMIAL_CHREC: + if (evolution_function_is_constant_p (CHREC_RIGHT (chrec))) + { + if (tree_fold_divides_p (CHREC_RIGHT (chrec), cst)) + /* Keep RES to true, and iterate on other dimensions. */ + return chrec_steps_divide_constant_p (CHREC_LEFT (chrec), cst, res); + + *res = false; + return true; + } + else + /* When the step is a parameter the result is undetermined. */ + return false; + + default: + /* On the initial condition, return true. */ + return true; + } +} + +/* Analyze a MIV (Multiple 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_miv_subscript (tree chrec_a, + tree chrec_b, + tree *overlaps_a, + tree *overlaps_b, + tree *last_conflicts) +{ + /* FIXME: This is a MIV subscript, not yet handled. + Example: (A[{1, +, 1}_1] vs. A[{1, +, 1}_2]) that comes from + (A[i] vs. A[j]). + + In the SIV test we had to solve a Diophantine equation with two + variables. In the MIV case we have to solve a Diophantine + equation with 2*n variables (if the subscript uses n IVs). + */ + bool divide_p = true; + tree difference; + dependence_stats.num_miv++; + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "(analyze_miv_subscript \n"); + + chrec_a = chrec_convert (integer_type_node, chrec_a, NULL_TREE); + chrec_b = chrec_convert (integer_type_node, chrec_b, NULL_TREE); + difference = chrec_fold_minus (integer_type_node, 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 = integer_zero_node; + *overlaps_b = integer_zero_node; + *last_conflicts = get_number_of_iters_for_loop (CHREC_VARIABLE (chrec_a)); + dependence_stats.num_miv_dependent++; + } + + else if (evolution_function_is_constant_p (difference) + /* For the moment, the following is verified: + evolution_function_is_affine_multivariate_p (chrec_a) */ + && chrec_steps_divide_constant_p (chrec_a, difference, ÷_p) + && !divide_p) + { + /* testsuite/.../ssa-chrec-33.c + {{21, +, 2}_1, +, -2}_2 vs. {{20, +, 2}_1, +, -2}_2 + + The difference is 1, and the evolution steps are equal to 2, + consequently there are no overlapping elements. */ + *overlaps_a = chrec_known; + *overlaps_b = chrec_known; + *last_conflicts = integer_zero_node; + dependence_stats.num_miv_independent++; + } + + else if (evolution_function_is_affine_multivariate_p (chrec_a) + && !chrec_contains_symbols (chrec_a) + && evolution_function_is_affine_multivariate_p (chrec_b) + && !chrec_contains_symbols (chrec_b)) + { + /* 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 (*overlaps_a == chrec_dont_know + || *overlaps_b == chrec_dont_know) + dependence_stats.num_miv_unimplemented++; + else if (*overlaps_a == chrec_known + || *overlaps_b == chrec_known) + 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 = chrec_dont_know; + *overlaps_b = chrec_dont_know; + *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. + 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, + tree *overlap_iterations_a, + tree *overlap_iterations_b, + tree *last_conflicts) +{ + 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, 0); + fprintf (dump_file, ")\n (chrec_b = "); + print_generic_expr (dump_file, chrec_b, 0); + 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 = chrec_dont_know; + *overlap_iterations_b = chrec_dont_know; + } + + /* 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)) + { + dependence_stats.num_same_subscript_function++; + *overlap_iterations_a = integer_zero_node; + *overlap_iterations_b = 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) + || !evolution_function_is_affine_multivariate_p (chrec_b))) + { + dependence_stats.num_subscript_undetermined++; + *overlap_iterations_a = chrec_dont_know; + *overlap_iterations_b = chrec_dont_know; + } + + 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); + + else + analyze_miv_subscript (chrec_a, chrec_b, + overlap_iterations_a, overlap_iterations_b, + last_conflicts); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " (overlap_iterations_a = "); + print_generic_expr (dump_file, *overlap_iterations_a, 0); + fprintf (dump_file, ")\n (overlap_iterations_b = "); + print_generic_expr (dump_file, *overlap_iterations_b, 0); + fprintf (dump_file, ")\n"); + 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) +{ + unsigned i; + lambda_vector v; + + for (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, v); i++) + if (lambda_vector_equal (v, dist_v, DDR_NB_LOOPS (ddr))) + return; + + VEC_safe_push (lambda_vector, heap, DDR_DIST_VECTS (ddr), dist_v); +} + +/* Helper function for uniquely inserting direction vectors. */ + +static void +save_dir_v (struct data_dependence_relation *ddr, lambda_vector dir_v) +{ + unsigned i; + lambda_vector v; + + for (i = 0; VEC_iterate (lambda_vector, DDR_DIR_VECTS (ddr), i, v); i++) + if (lambda_vector_equal (v, dir_v, DDR_NB_LOOPS (ddr))) + return; + + VEC_safe_push (lambda_vector, heap, DDR_DIR_VECTS (ddr), 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. 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, + struct data_reference *ddr_a, + struct data_reference *ddr_b, + lambda_vector dist_v, bool *init_b, + int *index_carry) +{ + unsigned i; + lambda_vector init_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); + + 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 = DR_ACCESS_FN (ddr_a, i); + access_fn_b = DR_ACCESS_FN (ddr_b, i); + + if (TREE_CODE (access_fn_a) == POLYNOMIAL_CHREC + && TREE_CODE (access_fn_b) == POLYNOMIAL_CHREC) + { + int dist, index; + int index_a = index_in_loop_nest (CHREC_VARIABLE (access_fn_a), + DDR_LOOP_NEST (ddr)); + int index_b = index_in_loop_nest (CHREC_VARIABLE (access_fn_b), + DDR_LOOP_NEST (ddr)); + + /* The dependence is carried by the outermost loop. Example: + | loop_1 + | A[{4, +, 1}_1] + | loop_2 + | A[{5, +, 1}_2] + | endloop_2 + | endloop_1 + In this case, the dependence is carried by loop_1. */ + index = index_a < index_b ? index_a : index_b; + *index_carry = MIN (index, *index_carry); + + if (chrec_contains_undetermined (SUB_DISTANCE (subscript))) + { + non_affine_dependence_relation (ddr); + return false; + } + + dist = int_cst_value (SUB_DISTANCE (subscript)); + + /* 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 + { + /* 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; + } + } + + return true; +} + +/* Return true when the DDR contains two data references that have the + same access functions. */ + +static bool +same_access_functions (struct data_dependence_relation *ddr) +{ + unsigned i; + + for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) + if (!eq_evolutions_p (DR_ACCESS_FN (DDR_A (ddr), i), + DR_ACCESS_FN (DDR_B (ddr), i))) + return false; + + return true; +} + +/* Helper function for the case where DDR_A and DDR_B are the same + multivariate access function. */ + +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; + + /* Polynomials with more than 2 variables are not handled yet. */ + if (TREE_CODE (c_0) != INTEGER_CST) + { + DDR_ARE_DEPENDENT (ddr) = chrec_dont_know; + 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)); + dist_v[x_1] = int_cst_value (CHREC_RIGHT (c_2)); + dist_v[x_2] = -int_cst_value (CHREC_RIGHT (c_1)); + 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); + + for (i = 0; i < DDR_NUM_SUBSCRIPTS (ddr); i++) + { + tree access_fun = DR_ACCESS_FN (DDR_A (ddr), i); + + if (TREE_CODE (access_fun) == POLYNOMIAL_CHREC) + { + if (!evolution_function_is_univariate_p (access_fun)) + { + if (DDR_NUM_SUBSCRIPTS (ddr) != 1) + { + DDR_ARE_DEPENDENT (ddr) = chrec_dont_know; + return; + } + + add_multivariate_self_dist (ddr, DR_ACCESS_FN (DDR_A (ddr), 0)); + return; + } + + 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); +} + +/* 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) +{ + bool init_b = false; + int index_carry = DDR_NB_LOOPS (ddr); + lambda_vector dist_v; + + if (DDR_ARE_DEPENDENT (ddr) != NULL_TREE) + return true; + + 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 (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, DDR_A (ddr), DDR_B (ddr), + 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)); + subscript_dependence_tester_1 (ddr, DDR_B (ddr), DDR_A (ddr)); + compute_subscript_distance (ddr); + build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr), + save_v, &init_b, &index_carry); + save_dist_v (ddr, save_v); + + /* 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)); + save_dist_v (ddr, save_v); + + if (DDR_NB_LOOPS (ddr) > 1) + { + lambda_vector opposite_v = lambda_vector_new (DDR_NB_LOOPS (ddr)); + + subscript_dependence_tester_1 (ddr, DDR_B (ddr), DDR_A (ddr)); + compute_subscript_distance (ddr); + build_classic_dist_vector_1 (ddr, DDR_B (ddr), DDR_A (ddr), + opposite_v, &init_b, &index_carry); + + add_outer_distances (ddr, dist_v, index_carry); + add_outer_distances (ddr, opposite_v, index_carry); + } + } + } + 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 (i = 0; VEC_iterate (lambda_vector, DDR_DIST_VECTS (ddr), i, dist_v); i++) + { + 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 + data references DRA and DRB. */ + +static bool +subscript_dependence_tester_1 (struct data_dependence_relation *ddr, + struct data_reference *dra, + struct data_reference *drb) +{ + unsigned int i; + tree last_conflicts; + struct subscript *subscript; + + for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript); + i++) + { + tree overlaps_a, overlaps_b; + + analyze_overlapping_iterations (DR_ACCESS_FN (dra, i), + DR_ACCESS_FN (drb, i), + &overlaps_a, &overlaps_b, + &last_conflicts); + + if (chrec_contains_undetermined (overlaps_a) + || chrec_contains_undetermined (overlaps_b)) + { + finalize_ddr_dependent (ddr, chrec_dont_know); + dependence_stats.num_dependence_undetermined++; + return false; + } + + else if (overlaps_a == chrec_known + || overlaps_b == chrec_known) + { + finalize_ddr_dependent (ddr, chrec_known); + dependence_stats.num_dependence_independent++; + return false; + } + + else + { + SUB_CONFLICTS_IN_A (subscript) = overlaps_a; + SUB_CONFLICTS_IN_B (subscript) = overlaps_b; + SUB_LAST_CONFLICT (subscript) = last_conflicts; + } + } + + return true; +} + +/* Computes the conflicting iterations, and initialize DDR. */ + +static void +subscript_dependence_tester (struct data_dependence_relation *ddr) +{ + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "(subscript_dependence_tester \n"); + + if (subscript_dependence_tester_1 (ddr, DDR_A (ddr), DDR_B (ddr))) + dependence_stats.num_dependence_dependent++; + + compute_subscript_distance (ddr); + if (build_classic_dist_vector (ddr)) + build_classic_dir_vector (ddr); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, ")\n"); +} + +/* Returns true when all the access functions of A are affine or + constant. */ + +static bool +access_functions_are_affine_or_constant_p (struct data_reference *a) +{ + unsigned int i; + VEC(tree,heap) **fns = DR_ACCESS_FNS_ADDR (a); + tree t; + + for (i = 0; VEC_iterate (tree, *fns, i, t); i++) + if (!evolution_function_is_constant_p (t) + && !evolution_function_is_affine_multivariate_p (t)) + return false; + + return true; +} + +/* This computes the affine dependence relation between A and B. + 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. */ + +static void +compute_affine_dependence (struct data_dependence_relation *ddr) +{ + 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, " (stmt_a = \n"); + print_generic_expr (dump_file, DR_STMT (dra), 0); + fprintf (dump_file, ")\n (stmt_b = \n"); + print_generic_expr (dump_file, DR_STMT (drb), 0); + fprintf (dump_file, ")\n"); + } + + /* 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) + && access_functions_are_affine_or_constant_p (drb)) + subscript_dependence_tester (ddr); + + /* 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)) + fprintf (dump_file, ")\n"); +} + +/* This computes the dependence relation for the same data + reference into DDR. */ + +static void +compute_self_dependence (struct data_dependence_relation *ddr) +{ + unsigned int i; + struct subscript *subscript; + + for (i = 0; VEC_iterate (subscript_p, DDR_SUBSCRIPTS (ddr), i, subscript); + i++) + { + /* The accessed index overlaps for each iteration. */ + SUB_CONFLICTS_IN_A (subscript) = integer_zero_node; + SUB_CONFLICTS_IN_B (subscript) = integer_zero_node; + SUB_LAST_CONFLICT (subscript) = chrec_dont_know; + } + + /* The distance vector is the zero vector. */ + save_dist_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr))); + save_dir_v (ddr, lambda_vector_new (DDR_NB_LOOPS (ddr))); +} + +/* 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. */ + +static void +compute_all_dependences (VEC (data_reference_p, heap) *datarefs, + VEC (ddr_p, heap) **dependence_relations, + VEC (loop_p, heap) *loop_nest, + bool compute_self_and_rr) +{ + struct data_dependence_relation *ddr; + struct data_reference *a, *b; + unsigned int i, j; + + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++) + for (j = i + 1; VEC_iterate (data_reference_p, datarefs, j, b); j++) + if (!DR_IS_READ (a) || !DR_IS_READ (b) || compute_self_and_rr) + { + ddr = initialize_data_dependence_relation (a, b, loop_nest); + VEC_safe_push (ddr_p, heap, *dependence_relations, ddr); + compute_affine_dependence (ddr); + } + + if (compute_self_and_rr) + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, a); i++) + { + ddr = initialize_data_dependence_relation (a, a, loop_nest); + VEC_safe_push (ddr_p, heap, *dependence_relations, ddr); + compute_self_dependence (ddr); + } +} + +/* 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 (struct loop *loop, + VEC (data_reference_p, heap) **datarefs) +{ + basic_block bb, *bbs; + unsigned int i; + block_stmt_iterator bsi; + struct data_reference *dr; + + bbs = get_loop_body (loop); + + for (i = 0; i < loop->num_nodes; i++) + { + bb = bbs[i]; + + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + { + tree stmt = bsi_stmt (bsi); + + /* ASM_EXPR and CALL_EXPR may embed arbitrary side effects. + Calls have side-effects, except those to const or pure + functions. */ + if ((TREE_CODE (stmt) == CALL_EXPR + && !(call_expr_flags (stmt) & (ECF_CONST | ECF_PURE))) + || (TREE_CODE (stmt) == ASM_EXPR + && ASM_VOLATILE_P (stmt))) + goto insert_dont_know_node; + + if (ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) + continue; + + switch (TREE_CODE (stmt)) + { + case MODIFY_EXPR: + { + bool one_inserted = false; + tree opnd0 = TREE_OPERAND (stmt, 0); + tree opnd1 = TREE_OPERAND (stmt, 1); + + if (TREE_CODE (opnd0) == ARRAY_REF + || TREE_CODE (opnd0) == INDIRECT_REF + || TREE_CODE (opnd0) == COMPONENT_REF) + { + dr = create_data_ref (opnd0, stmt, false); + if (dr) + { + VEC_safe_push (data_reference_p, heap, *datarefs, dr); + one_inserted = true; + } + } + + if (TREE_CODE (opnd1) == ARRAY_REF + || TREE_CODE (opnd1) == INDIRECT_REF + || TREE_CODE (opnd1) == COMPONENT_REF) + { + dr = create_data_ref (opnd1, stmt, true); + if (dr) + { + VEC_safe_push (data_reference_p, heap, *datarefs, dr); + one_inserted = true; + } + } + + if (!one_inserted) + goto insert_dont_know_node; + + break; + } + + case CALL_EXPR: + { + tree args; + bool one_inserted = false; + + for (args = TREE_OPERAND (stmt, 1); args; + args = TREE_CHAIN (args)) + if (TREE_CODE (TREE_VALUE (args)) == ARRAY_REF + || TREE_CODE (TREE_VALUE (args)) == INDIRECT_REF + || TREE_CODE (TREE_VALUE (args)) == COMPONENT_REF) + { + dr = create_data_ref (TREE_VALUE (args), stmt, true); + if (dr) + { + VEC_safe_push (data_reference_p, heap, *datarefs, dr); + one_inserted = true; + } + } + + if (!one_inserted) + goto insert_dont_know_node; + + break; + } + + default: + { + struct data_reference *res; + + insert_dont_know_node:; + res = XNEW (struct data_reference); + DR_STMT (res) = NULL_TREE; + DR_REF (res) = NULL_TREE; + DR_BASE_OBJECT (res) = NULL; + DR_TYPE (res) = ARRAY_REF_TYPE; + DR_SET_ACCESS_FNS (res, NULL); + DR_BASE_OBJECT (res) = NULL; + DR_IS_READ (res) = false; + DR_BASE_ADDRESS (res) = NULL_TREE; + DR_OFFSET (res) = NULL_TREE; + DR_INIT (res) = NULL_TREE; + DR_STEP (res) = NULL_TREE; + DR_OFFSET_MISALIGNMENT (res) = NULL_TREE; + DR_MEMTAG (res) = NULL_TREE; + DR_PTR_INFO (res) = NULL; + VEC_safe_push (data_reference_p, heap, *datarefs, res); + + free (bbs); + return chrec_dont_know; + } + } + + /* When there are no defs in the loop, the loop is parallel. */ + if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS)) + loop->parallel_p = false; + } + } + + free (bbs); + + return NULL_TREE; +} + +/* Recursive helper function. */ + +static bool +find_loop_nest_1 (struct loop *loop, VEC (loop_p, heap) **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; + + VEC_safe_push (loop_p, heap, *loop_nest, 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. */ + +static bool +find_loop_nest (struct loop *loop, VEC (loop_p, heap) **loop_nest) +{ + VEC_safe_push (loop_p, heap, *loop_nest, loop); + if (loop->inner) + return find_loop_nest_1 (loop->inner, loop_nest); + return true; +} + +/* 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. */ + +void +compute_data_dependences_for_loop (struct loop *loop, + bool compute_self_and_read_read_dependences, + VEC (data_reference_p, heap) **datarefs, + VEC (ddr_p, heap) **dependence_relations) +{ + struct loop *loop_nest = loop; + VEC (loop_p, heap) *vloops = VEC_alloc (loop_p, heap, 3); + + 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_nest + || !find_loop_nest (loop_nest, &vloops) + || find_data_references_in_loop (loop, datarefs) == chrec_dont_know) + { + struct data_dependence_relation *ddr; + + /* Insert a single relation into dependence_relations: + chrec_dont_know. */ + ddr = initialize_data_dependence_relation (NULL, NULL, vloops); + VEC_safe_push (ddr_p, heap, *dependence_relations, ddr); + } + else + compute_all_dependences (*datarefs, dependence_relations, vloops, + compute_self_and_read_read_dependences); + + 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); + } +} + +/* Entry point (for testing only). Analyze all the data references + and the dependence relations. + + The data references are computed first. + + A relation on these nodes is represented by a complete graph. Some + of the relations could be of no interest, thus the relations can be + computed on demand. + + In the following function we compute all the relations. This is + just a first implementation that is here for: + - for showing how to ask for the dependence relations, + - for the debugging the whole dependence graph, + - for the dejagnu testcases and maintenance. + + It is possible to ask only for a part of the graph, avoiding to + compute the whole dependence graph. The computed dependences are + stored in a knowledge base (KB) such that later queries don't + recompute the same information. The implementation of this KB is + transparent to the optimizer, and thus the KB can be changed with a + more efficient implementation, or the KB could be disabled. */ +#if 0 +static void +analyze_all_data_dependences (struct loops *loops) +{ + unsigned int i; + int nb_data_refs = 10; + VEC (data_reference_p, heap) *datarefs = + VEC_alloc (data_reference_p, heap, nb_data_refs); + VEC (ddr_p, heap) *dependence_relations = + VEC_alloc (ddr_p, heap, nb_data_refs * nb_data_refs); + + /* Compute DDs on the whole function. */ + compute_data_dependences_for_loop (loops->parray[0], false, + &datarefs, &dependence_relations); + + if (dump_file) + { + dump_data_dependence_relations (dump_file, dependence_relations); + fprintf (dump_file, "\n\n"); + + if (dump_flags & TDF_DETAILS) + dump_dist_dir_vectors (dump_file, dependence_relations); + + if (dump_flags & TDF_STATS) + { + unsigned nb_top_relations = 0; + unsigned nb_bot_relations = 0; + unsigned nb_basename_differ = 0; + unsigned nb_chrec_relations = 0; + struct data_dependence_relation *ddr; + + for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++) + { + if (chrec_contains_undetermined (DDR_ARE_DEPENDENT (ddr))) + nb_top_relations++; + + else if (DDR_ARE_DEPENDENT (ddr) == chrec_known) + { + struct data_reference *a = DDR_A (ddr); + struct data_reference *b = DDR_B (ddr); + bool differ_p; + + if ((DR_BASE_OBJECT (a) && DR_BASE_OBJECT (b) + && DR_NUM_DIMENSIONS (a) != DR_NUM_DIMENSIONS (b)) + || (base_object_differ_p (a, b, &differ_p) + && differ_p)) + nb_basename_differ++; + else + nb_bot_relations++; + } + + else + nb_chrec_relations++; + } + + gather_stats_on_scev_database (); + } + } + + free_dependence_relations (dependence_relations); + free_data_refs (datarefs); +} +#endif + +/* 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_ARE_DEPENDENT (ddr) == NULL_TREE && DDR_SUBSCRIPTS (ddr)) + VEC_free (subscript_p, heap, DDR_SUBSCRIPTS (ddr)); + + free (ddr); +} + +/* Free the memory used by the data dependence relations from + DEPENDENCE_RELATIONS. */ + +void +free_dependence_relations (VEC (ddr_p, heap) *dependence_relations) +{ + unsigned int i; + struct data_dependence_relation *ddr; + VEC (loop_p, heap) *loop_nest = NULL; + + for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++) + { + if (ddr == NULL) + continue; + if (loop_nest == NULL) + loop_nest = DDR_LOOP_NEST (ddr); + else + gcc_assert (DDR_LOOP_NEST (ddr) == NULL + || DDR_LOOP_NEST (ddr) == loop_nest); + free_dependence_relation (ddr); + } + + if (loop_nest) + VEC_free (loop_p, heap, loop_nest); + VEC_free (ddr_p, heap, dependence_relations); +} + +/* Free the memory used by the data references from DATAREFS. */ + +void +free_data_refs (VEC (data_reference_p, heap) *datarefs) +{ + unsigned int i; + struct data_reference *dr; + + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) + free_data_ref (dr); + VEC_free (data_reference_p, heap, datarefs); +} + |
