| /* Dependency analysis |
| Copyright (C) 2000, 2001, 2002, 2005, 2006, 2007 |
| Free Software Foundation, Inc. |
| Contributed by Paul Brook <paul@nowt.org> |
| |
| 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. */ |
| |
| /* dependency.c -- Expression dependency analysis code. */ |
| /* There's probably quite a bit of duplication in this file. We currently |
| have different dependency checking functions for different types |
| if dependencies. Ideally these would probably be merged. */ |
| |
| |
| #include "config.h" |
| #include "gfortran.h" |
| #include "dependency.h" |
| |
| /* static declarations */ |
| /* Enums */ |
| enum range {LHS, RHS, MID}; |
| |
| /* Dependency types. These must be in reverse order of priority. */ |
| typedef enum |
| { |
| GFC_DEP_ERROR, |
| GFC_DEP_EQUAL, /* Identical Ranges. */ |
| GFC_DEP_FORWARD, /* eg. a(1:3), a(2:4). */ |
| GFC_DEP_OVERLAP, /* May overlap in some other way. */ |
| GFC_DEP_NODEP /* Distinct ranges. */ |
| } |
| gfc_dependency; |
| |
| /* Macros */ |
| #define IS_ARRAY_EXPLICIT(as) ((as->type == AS_EXPLICIT ? 1 : 0)) |
| |
| |
| /* Returns 1 if the expr is an integer constant value 1, 0 if it is not or |
| def if the value could not be determined. */ |
| |
| int |
| gfc_expr_is_one (gfc_expr * expr, int def) |
| { |
| gcc_assert (expr != NULL); |
| |
| if (expr->expr_type != EXPR_CONSTANT) |
| return def; |
| |
| if (expr->ts.type != BT_INTEGER) |
| return def; |
| |
| return mpz_cmp_si (expr->value.integer, 1) == 0; |
| } |
| |
| |
| /* Compare two values. Returns 0 if e1 == e2, -1 if e1 < e2, +1 if e1 > e2, |
| and -2 if the relationship could not be determined. */ |
| |
| int |
| gfc_dep_compare_expr (gfc_expr * e1, gfc_expr * e2) |
| { |
| gfc_actual_arglist *args1; |
| gfc_actual_arglist *args2; |
| int i; |
| |
| if (e1->expr_type == EXPR_OP |
| && (e1->value.op.operator == INTRINSIC_UPLUS |
| || e1->value.op.operator == INTRINSIC_PARENTHESES)) |
| return gfc_dep_compare_expr (e1->value.op.op1, e2); |
| if (e2->expr_type == EXPR_OP |
| && (e2->value.op.operator == INTRINSIC_UPLUS |
| || e2->value.op.operator == INTRINSIC_PARENTHESES)) |
| return gfc_dep_compare_expr (e1, e2->value.op.op1); |
| |
| if (e1->expr_type == EXPR_OP |
| && e1->value.op.operator == INTRINSIC_PLUS) |
| { |
| /* Compare X+C vs. X. */ |
| if (e1->value.op.op2->expr_type == EXPR_CONSTANT |
| && e1->value.op.op2->ts.type == BT_INTEGER |
| && gfc_dep_compare_expr (e1->value.op.op1, e2) == 0) |
| return mpz_sgn (e1->value.op.op2->value.integer); |
| |
| /* Compare P+Q vs. R+S. */ |
| if (e2->expr_type == EXPR_OP |
| && e2->value.op.operator == INTRINSIC_PLUS) |
| { |
| int l, r; |
| |
| l = gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op1); |
| r = gfc_dep_compare_expr (e1->value.op.op2, e2->value.op.op2); |
| if (l == 0 && r == 0) |
| return 0; |
| if (l == 0 && r != -2) |
| return r; |
| if (l != -2 && r == 0) |
| return l; |
| if (l == 1 && r == 1) |
| return 1; |
| if (l == -1 && r == -1) |
| return -1; |
| |
| l = gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op2); |
| r = gfc_dep_compare_expr (e1->value.op.op2, e2->value.op.op1); |
| if (l == 0 && r == 0) |
| return 0; |
| if (l == 0 && r != -2) |
| return r; |
| if (l != -2 && r == 0) |
| return l; |
| if (l == 1 && r == 1) |
| return 1; |
| if (l == -1 && r == -1) |
| return -1; |
| } |
| } |
| |
| /* Compare X vs. X+C. */ |
| if (e2->expr_type == EXPR_OP |
| && e2->value.op.operator == INTRINSIC_PLUS) |
| { |
| if (e2->value.op.op2->expr_type == EXPR_CONSTANT |
| && e2->value.op.op2->ts.type == BT_INTEGER |
| && gfc_dep_compare_expr (e1, e2->value.op.op1) == 0) |
| return -mpz_sgn (e2->value.op.op2->value.integer); |
| } |
| |
| /* Compare X-C vs. X. */ |
| if (e1->expr_type == EXPR_OP |
| && e1->value.op.operator == INTRINSIC_MINUS) |
| { |
| if (e1->value.op.op2->expr_type == EXPR_CONSTANT |
| && e1->value.op.op2->ts.type == BT_INTEGER |
| && gfc_dep_compare_expr (e1->value.op.op1, e2) == 0) |
| return -mpz_sgn (e1->value.op.op2->value.integer); |
| |
| /* Compare P-Q vs. R-S. */ |
| if (e2->expr_type == EXPR_OP |
| && e2->value.op.operator == INTRINSIC_MINUS) |
| { |
| int l, r; |
| |
| l = gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op1); |
| r = gfc_dep_compare_expr (e1->value.op.op2, e2->value.op.op2); |
| if (l == 0 && r == 0) |
| return 0; |
| if (l != -2 && r == 0) |
| return l; |
| if (l == 0 && r != -2) |
| return -r; |
| if (l == 1 && r == -1) |
| return 1; |
| if (l == -1 && r == 1) |
| return -1; |
| } |
| } |
| |
| /* Compare X vs. X-C. */ |
| if (e2->expr_type == EXPR_OP |
| && e2->value.op.operator == INTRINSIC_MINUS) |
| { |
| if (e2->value.op.op2->expr_type == EXPR_CONSTANT |
| && e2->value.op.op2->ts.type == BT_INTEGER |
| && gfc_dep_compare_expr (e1, e2->value.op.op1) == 0) |
| return mpz_sgn (e2->value.op.op2->value.integer); |
| } |
| |
| if (e1->expr_type != e2->expr_type) |
| return -2; |
| |
| switch (e1->expr_type) |
| { |
| case EXPR_CONSTANT: |
| if (e1->ts.type != BT_INTEGER || e2->ts.type != BT_INTEGER) |
| return -2; |
| |
| i = mpz_cmp (e1->value.integer, e2->value.integer); |
| if (i == 0) |
| return 0; |
| else if (i < 0) |
| return -1; |
| return 1; |
| |
| case EXPR_VARIABLE: |
| if (e1->ref || e2->ref) |
| return -2; |
| if (e1->symtree->n.sym == e2->symtree->n.sym) |
| return 0; |
| return -2; |
| |
| case EXPR_OP: |
| /* Intrinsic operators are the same if their operands are the same. */ |
| if (e1->value.op.operator != e2->value.op.operator) |
| return -2; |
| if (e1->value.op.op2 == 0) |
| { |
| i = gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op1); |
| return i == 0 ? 0 : -2; |
| } |
| if (gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op1) == 0 |
| && gfc_dep_compare_expr (e1->value.op.op2, e2->value.op.op2) == 0) |
| return 0; |
| /* TODO Handle commutative binary operators here? */ |
| return -2; |
| |
| case EXPR_FUNCTION: |
| /* We can only compare calls to the same intrinsic function. */ |
| if (e1->value.function.isym == 0 |
| || e2->value.function.isym == 0 |
| || e1->value.function.isym != e2->value.function.isym) |
| return -2; |
| |
| args1 = e1->value.function.actual; |
| args2 = e2->value.function.actual; |
| |
| /* We should list the "constant" intrinsic functions. Those |
| without side-effects that provide equal results given equal |
| argument lists. */ |
| switch (e1->value.function.isym->generic_id) |
| { |
| case GFC_ISYM_CONVERSION: |
| /* Handle integer extensions specially, as __convert_i4_i8 |
| is not only "constant" but also "unary" and "increasing". */ |
| if (args1 && !args1->next |
| && args2 && !args2->next |
| && e1->ts.type == BT_INTEGER |
| && args1->expr->ts.type == BT_INTEGER |
| && e1->ts.kind > args1->expr->ts.kind |
| && e2->ts.type == e1->ts.type |
| && e2->ts.kind == e1->ts.kind |
| && args2->expr->ts.type == args1->expr->ts.type |
| && args2->expr->ts.kind == args2->expr->ts.kind) |
| return gfc_dep_compare_expr (args1->expr, args2->expr); |
| break; |
| |
| case GFC_ISYM_REAL: |
| case GFC_ISYM_LOGICAL: |
| case GFC_ISYM_DBLE: |
| break; |
| |
| default: |
| return -2; |
| } |
| |
| /* Compare the argument lists for equality. */ |
| while (args1 && args2) |
| { |
| if (gfc_dep_compare_expr (args1->expr, args2->expr) != 0) |
| return -2; |
| args1 = args1->next; |
| args2 = args2->next; |
| } |
| return (args1 || args2) ? -2 : 0; |
| |
| default: |
| return -2; |
| } |
| } |
| |
| |
| /* Returns 1 if the two ranges are the same, 0 if they are not, and def |
| if the results are indeterminate. N is the dimension to compare. */ |
| |
| int |
| gfc_is_same_range (gfc_array_ref * ar1, gfc_array_ref * ar2, int n, int def) |
| { |
| gfc_expr *e1; |
| gfc_expr *e2; |
| int i; |
| |
| /* TODO: More sophisticated range comparison. */ |
| gcc_assert (ar1 && ar2); |
| |
| gcc_assert (ar1->dimen_type[n] == ar2->dimen_type[n]); |
| |
| e1 = ar1->stride[n]; |
| e2 = ar2->stride[n]; |
| /* Check for mismatching strides. A NULL stride means a stride of 1. */ |
| if (e1 && !e2) |
| { |
| i = gfc_expr_is_one (e1, -1); |
| if (i == -1) |
| return def; |
| else if (i == 0) |
| return 0; |
| } |
| else if (e2 && !e1) |
| { |
| i = gfc_expr_is_one (e2, -1); |
| if (i == -1) |
| return def; |
| else if (i == 0) |
| return 0; |
| } |
| else if (e1 && e2) |
| { |
| i = gfc_dep_compare_expr (e1, e2); |
| if (i == -2) |
| return def; |
| else if (i != 0) |
| return 0; |
| } |
| /* The strides match. */ |
| |
| /* Check the range start. */ |
| e1 = ar1->start[n]; |
| e2 = ar2->start[n]; |
| if (e1 || e2) |
| { |
| /* Use the bound of the array if no bound is specified. */ |
| if (ar1->as && !e1) |
| e1 = ar1->as->lower[n]; |
| |
| if (ar2->as && !e2) |
| e2 = ar2->as->lower[n]; |
| |
| /* Check we have values for both. */ |
| if (!(e1 && e2)) |
| return def; |
| |
| i = gfc_dep_compare_expr (e1, e2); |
| if (i == -2) |
| return def; |
| else if (i != 0) |
| return 0; |
| } |
| |
| /* Check the range end. */ |
| e1 = ar1->end[n]; |
| e2 = ar2->end[n]; |
| if (e1 || e2) |
| { |
| /* Use the bound of the array if no bound is specified. */ |
| if (ar1->as && !e1) |
| e1 = ar1->as->upper[n]; |
| |
| if (ar2->as && !e2) |
| e2 = ar2->as->upper[n]; |
| |
| /* Check we have values for both. */ |
| if (!(e1 && e2)) |
| return def; |
| |
| i = gfc_dep_compare_expr (e1, e2); |
| if (i == -2) |
| return def; |
| else if (i != 0) |
| return 0; |
| } |
| |
| return 1; |
| } |
| |
| |
| /* Some array-returning intrinsics can be implemented by reusing the |
| data from one of the array arguments. For example, TRANSPOSE does |
| not necessarily need to allocate new data: it can be implemented |
| by copying the original array's descriptor and simply swapping the |
| two dimension specifications. |
| |
| If EXPR is a call to such an intrinsic, return the argument |
| whose data can be reused, otherwise return NULL. */ |
| |
| gfc_expr * |
| gfc_get_noncopying_intrinsic_argument (gfc_expr * expr) |
| { |
| if (expr->expr_type != EXPR_FUNCTION || !expr->value.function.isym) |
| return NULL; |
| |
| switch (expr->value.function.isym->generic_id) |
| { |
| case GFC_ISYM_TRANSPOSE: |
| return expr->value.function.actual->expr; |
| |
| default: |
| return NULL; |
| } |
| } |
| |
| |
| /* Return true if the result of reference REF can only be constructed |
| using a temporary array. */ |
| |
| bool |
| gfc_ref_needs_temporary_p (gfc_ref *ref) |
| { |
| int n; |
| bool subarray_p; |
| |
| subarray_p = false; |
| for (; ref; ref = ref->next) |
| switch (ref->type) |
| { |
| case REF_ARRAY: |
| /* Vector dimensions are generally not monotonic and must be |
| handled using a temporary. */ |
| if (ref->u.ar.type == AR_SECTION) |
| for (n = 0; n < ref->u.ar.dimen; n++) |
| if (ref->u.ar.dimen_type[n] == DIMEN_VECTOR) |
| return true; |
| |
| subarray_p = true; |
| break; |
| |
| case REF_SUBSTRING: |
| /* Within an array reference, character substrings generally |
| need a temporary. Character array strides are expressed as |
| multiples of the element size (consistent with other array |
| types), not in characters. */ |
| return subarray_p; |
| |
| case REF_COMPONENT: |
| break; |
| } |
| |
| return false; |
| } |
| |
| |
| /* Return true if array variable VAR could be passed to the same function |
| as argument EXPR without interfering with EXPR. INTENT is the intent |
| of VAR. |
| |
| This is considerably less conservative than other dependencies |
| because many function arguments will already be copied into a |
| temporary. */ |
| |
| static int |
| gfc_check_argument_var_dependency (gfc_expr * var, sym_intent intent, |
| gfc_expr * expr) |
| { |
| gcc_assert (var->expr_type == EXPR_VARIABLE); |
| gcc_assert (var->rank > 0); |
| |
| switch (expr->expr_type) |
| { |
| case EXPR_VARIABLE: |
| return (gfc_ref_needs_temporary_p (expr->ref) |
| || gfc_check_dependency (var, expr, 1)); |
| |
| case EXPR_ARRAY: |
| return gfc_check_dependency (var, expr, 1); |
| |
| case EXPR_FUNCTION: |
| if (intent != INTENT_IN && expr->inline_noncopying_intrinsic) |
| { |
| expr = gfc_get_noncopying_intrinsic_argument (expr); |
| return gfc_check_argument_var_dependency (var, intent, expr); |
| } |
| return 0; |
| |
| default: |
| return 0; |
| } |
| } |
| |
| |
| /* Like gfc_check_argument_var_dependency, but extended to any |
| array expression OTHER, not just variables. */ |
| |
| static int |
| gfc_check_argument_dependency (gfc_expr * other, sym_intent intent, |
| gfc_expr * expr) |
| { |
| switch (other->expr_type) |
| { |
| case EXPR_VARIABLE: |
| return gfc_check_argument_var_dependency (other, intent, expr); |
| |
| case EXPR_FUNCTION: |
| if (other->inline_noncopying_intrinsic) |
| { |
| other = gfc_get_noncopying_intrinsic_argument (other); |
| return gfc_check_argument_dependency (other, INTENT_IN, expr); |
| } |
| return 0; |
| |
| default: |
| return 0; |
| } |
| } |
| |
| |
| /* Like gfc_check_argument_dependency, but check all the arguments in ACTUAL. |
| FNSYM is the function being called, or NULL if not known. */ |
| |
| int |
| gfc_check_fncall_dependency (gfc_expr * other, sym_intent intent, |
| gfc_symbol * fnsym, gfc_actual_arglist * actual) |
| { |
| gfc_formal_arglist *formal; |
| gfc_expr *expr; |
| |
| formal = fnsym ? fnsym->formal : NULL; |
| for (; actual; actual = actual->next, formal = formal ? formal->next : NULL) |
| { |
| expr = actual->expr; |
| |
| /* Skip args which are not present. */ |
| if (!expr) |
| continue; |
| |
| /* Skip other itself. */ |
| if (expr == other) |
| continue; |
| |
| /* Skip intent(in) arguments if OTHER itself is intent(in). */ |
| if (formal |
| && intent == INTENT_IN |
| && formal->sym->attr.intent == INTENT_IN) |
| continue; |
| |
| if (gfc_check_argument_dependency (other, intent, expr)) |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| |
| /* Return 1 if e1 and e2 are equivalenced arrays, either |
| directly or indirectly; ie. equivalence (a,b) for a and b |
| or equivalence (a,c),(b,c). This function uses the equiv_ |
| lists, generated in trans-common(add_equivalences), that are |
| guaranteed to pick up indirect equivalences. We explicitly |
| check for overlap using the offset and length of the equivalence. |
| This function is symmetric. |
| TODO: This function only checks whether the full top-level |
| symbols overlap. An improved implementation could inspect |
| e1->ref and e2->ref to determine whether the actually accessed |
| portions of these variables/arrays potentially overlap. */ |
| |
| int |
| gfc_are_equivalenced_arrays (gfc_expr *e1, gfc_expr *e2) |
| { |
| gfc_equiv_list *l; |
| gfc_equiv_info *s, *fl1, *fl2; |
| |
| gcc_assert (e1->expr_type == EXPR_VARIABLE |
| && e2->expr_type == EXPR_VARIABLE); |
| |
| if (!e1->symtree->n.sym->attr.in_equivalence |
| || !e2->symtree->n.sym->attr.in_equivalence |
| || !e1->rank |
| || !e2->rank) |
| return 0; |
| |
| /* Go through the equiv_lists and return 1 if the variables |
| e1 and e2 are members of the same group and satisfy the |
| requirement on their relative offsets. */ |
| for (l = gfc_current_ns->equiv_lists; l; l = l->next) |
| { |
| fl1 = NULL; |
| fl2 = NULL; |
| for (s = l->equiv; s; s = s->next) |
| { |
| if (s->sym == e1->symtree->n.sym) |
| { |
| fl1 = s; |
| if (fl2) |
| break; |
| } |
| if (s->sym == e2->symtree->n.sym) |
| { |
| fl2 = s; |
| if (fl1) |
| break; |
| } |
| } |
| |
| if (s) |
| { |
| /* Can these lengths be zero? */ |
| if (fl1->length <= 0 || fl2->length <= 0) |
| return 1; |
| /* These can't overlap if [f11,fl1+length] is before |
| [fl2,fl2+length], or [fl2,fl2+length] is before |
| [fl1,fl1+length], otherwise they do overlap. */ |
| if (fl1->offset + fl1->length > fl2->offset |
| && fl2->offset + fl2->length > fl1->offset) |
| return 1; |
| } |
| } |
| return 0; |
| } |
| |
| |
| /* Return true if the statement body redefines the condition. Returns |
| true if expr2 depends on expr1. expr1 should be a single term |
| suitable for the lhs of an assignment. The IDENTICAL flag indicates |
| whether array references to the same symbol with identical range |
| references count as a dependency or not. Used for forall and where |
| statements. Also used with functions returning arrays without a |
| temporary. */ |
| |
| int |
| gfc_check_dependency (gfc_expr * expr1, gfc_expr * expr2, bool identical) |
| { |
| gfc_ref *ref; |
| int n; |
| gfc_actual_arglist *actual; |
| |
| gcc_assert (expr1->expr_type == EXPR_VARIABLE); |
| |
| switch (expr2->expr_type) |
| { |
| case EXPR_OP: |
| n = gfc_check_dependency (expr1, expr2->value.op.op1, identical); |
| if (n) |
| return n; |
| if (expr2->value.op.op2) |
| return gfc_check_dependency (expr1, expr2->value.op.op2, identical); |
| return 0; |
| |
| case EXPR_VARIABLE: |
| /* The interesting cases are when the symbols don't match. */ |
| if (expr1->symtree->n.sym != expr2->symtree->n.sym) |
| { |
| gfc_typespec *ts1 = &expr1->symtree->n.sym->ts; |
| gfc_typespec *ts2 = &expr2->symtree->n.sym->ts; |
| |
| /* Return 1 if expr1 and expr2 are equivalenced arrays. */ |
| if (gfc_are_equivalenced_arrays (expr1, expr2)) |
| return 1; |
| |
| /* Symbols can only alias if they have the same type. */ |
| if (ts1->type != BT_UNKNOWN |
| && ts2->type != BT_UNKNOWN |
| && ts1->type != BT_DERIVED |
| && ts2->type != BT_DERIVED) |
| { |
| if (ts1->type != ts2->type |
| || ts1->kind != ts2->kind) |
| return 0; |
| } |
| |
| /* If either variable is a pointer, assume the worst. */ |
| /* TODO: -fassume-no-pointer-aliasing */ |
| if (expr1->symtree->n.sym->attr.pointer) |
| return 1; |
| for (ref = expr1->ref; ref; ref = ref->next) |
| if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) |
| return 1; |
| |
| if (expr2->symtree->n.sym->attr.pointer) |
| return 1; |
| for (ref = expr2->ref; ref; ref = ref->next) |
| if (ref->type == REF_COMPONENT && ref->u.c.component->pointer) |
| return 1; |
| |
| /* Otherwise distinct symbols have no dependencies. */ |
| return 0; |
| } |
| |
| if (identical) |
| return 1; |
| |
| /* Identical and disjoint ranges return 0, |
| overlapping ranges return 1. */ |
| /* Return zero if we refer to the same full arrays. */ |
| if (expr1->ref->type == REF_ARRAY && expr2->ref->type == REF_ARRAY) |
| return gfc_dep_resolver (expr1->ref, expr2->ref); |
| |
| return 1; |
| |
| case EXPR_FUNCTION: |
| if (expr2->inline_noncopying_intrinsic) |
| identical = 1; |
| /* Remember possible differences between elemental and |
| transformational functions. All functions inside a FORALL |
| will be pure. */ |
| for (actual = expr2->value.function.actual; |
| actual; actual = actual->next) |
| { |
| if (!actual->expr) |
| continue; |
| n = gfc_check_dependency (expr1, actual->expr, identical); |
| if (n) |
| return n; |
| } |
| return 0; |
| |
| case EXPR_CONSTANT: |
| case EXPR_NULL: |
| return 0; |
| |
| case EXPR_ARRAY: |
| /* Probably ok in the majority of (constant) cases. */ |
| return 1; |
| |
| default: |
| return 1; |
| } |
| } |
| |
| |
| /* Determines overlapping for two array sections. */ |
| |
| static gfc_dependency |
| gfc_check_section_vs_section (gfc_ref * lref, gfc_ref * rref, int n) |
| { |
| gfc_array_ref l_ar; |
| gfc_expr *l_start; |
| gfc_expr *l_end; |
| gfc_expr *l_stride; |
| gfc_expr *l_lower; |
| gfc_expr *l_upper; |
| int l_dir; |
| |
| gfc_array_ref r_ar; |
| gfc_expr *r_start; |
| gfc_expr *r_end; |
| gfc_expr *r_stride; |
| gfc_expr *r_lower; |
| gfc_expr *r_upper; |
| int r_dir; |
| |
| l_ar = lref->u.ar; |
| r_ar = rref->u.ar; |
| |
| /* If they are the same range, return without more ado. */ |
| if (gfc_is_same_range (&l_ar, &r_ar, n, 0)) |
| return GFC_DEP_EQUAL; |
| |
| l_start = l_ar.start[n]; |
| l_end = l_ar.end[n]; |
| l_stride = l_ar.stride[n]; |
| |
| r_start = r_ar.start[n]; |
| r_end = r_ar.end[n]; |
| r_stride = r_ar.stride[n]; |
| |
| /* If l_start is NULL take it from array specifier. */ |
| if (NULL == l_start && IS_ARRAY_EXPLICIT (l_ar.as)) |
| l_start = l_ar.as->lower[n]; |
| /* If l_end is NULL take it from array specifier. */ |
| if (NULL == l_end && IS_ARRAY_EXPLICIT (l_ar.as)) |
| l_end = l_ar.as->upper[n]; |
| |
| /* If r_start is NULL take it from array specifier. */ |
| if (NULL == r_start && IS_ARRAY_EXPLICIT (r_ar.as)) |
| r_start = r_ar.as->lower[n]; |
| /* If r_end is NULL take it from array specifier. */ |
| if (NULL == r_end && IS_ARRAY_EXPLICIT (r_ar.as)) |
| r_end = r_ar.as->upper[n]; |
| |
| /* Determine whether the l_stride is positive or negative. */ |
| if (!l_stride) |
| l_dir = 1; |
| else if (l_stride->expr_type == EXPR_CONSTANT |
| && l_stride->ts.type == BT_INTEGER) |
| l_dir = mpz_sgn (l_stride->value.integer); |
| else if (l_start && l_end) |
| l_dir = gfc_dep_compare_expr (l_end, l_start); |
| else |
| l_dir = -2; |
| |
| /* Determine whether the r_stride is positive or negative. */ |
| if (!r_stride) |
| r_dir = 1; |
| else if (r_stride->expr_type == EXPR_CONSTANT |
| && r_stride->ts.type == BT_INTEGER) |
| r_dir = mpz_sgn (r_stride->value.integer); |
| else if (r_start && r_end) |
| r_dir = gfc_dep_compare_expr (r_end, r_start); |
| else |
| r_dir = -2; |
| |
| /* The strides should never be zero. */ |
| if (l_dir == 0 || r_dir == 0) |
| return GFC_DEP_OVERLAP; |
| |
| /* Determine LHS upper and lower bounds. */ |
| if (l_dir == 1) |
| { |
| l_lower = l_start; |
| l_upper = l_end; |
| } |
| else if (l_dir == -1) |
| { |
| l_lower = l_end; |
| l_upper = l_start; |
| } |
| else |
| { |
| l_lower = NULL; |
| l_upper = NULL; |
| } |
| |
| /* Determine RHS upper and lower bounds. */ |
| if (r_dir == 1) |
| { |
| r_lower = r_start; |
| r_upper = r_end; |
| } |
| else if (r_dir == -1) |
| { |
| r_lower = r_end; |
| r_upper = r_start; |
| } |
| else |
| { |
| r_lower = NULL; |
| r_upper = NULL; |
| } |
| |
| /* Check whether the ranges are disjoint. */ |
| if (l_upper && r_lower && gfc_dep_compare_expr (l_upper, r_lower) == -1) |
| return GFC_DEP_NODEP; |
| if (r_upper && l_lower && gfc_dep_compare_expr (r_upper, l_lower) == -1) |
| return GFC_DEP_NODEP; |
| |
| /* Handle cases like x:y:1 vs. x:z:-1 as GFC_DEP_EQUAL. */ |
| if (l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == 0) |
| { |
| if (l_dir == 1 && r_dir == -1) |
| return GFC_DEP_EQUAL; |
| if (l_dir == -1 && r_dir == 1) |
| return GFC_DEP_EQUAL; |
| } |
| |
| /* Handle cases like x:y:1 vs. z:y:-1 as GFC_DEP_EQUAL. */ |
| if (l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == 0) |
| { |
| if (l_dir == 1 && r_dir == -1) |
| return GFC_DEP_EQUAL; |
| if (l_dir == -1 && r_dir == 1) |
| return GFC_DEP_EQUAL; |
| } |
| |
| /* Check for forward dependencies x:y vs. x+1:z. */ |
| if (l_dir == 1 && r_dir == 1 |
| && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == -1 |
| && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == -1) |
| { |
| /* Check that the strides are the same. */ |
| if (!l_stride && !r_stride) |
| return GFC_DEP_FORWARD; |
| if (l_stride && r_stride |
| && gfc_dep_compare_expr (l_stride, r_stride) == 0) |
| return GFC_DEP_FORWARD; |
| } |
| |
| /* Check for forward dependencies x:y:-1 vs. x-1:z:-1. */ |
| if (l_dir == -1 && r_dir == -1 |
| && l_start && r_start && gfc_dep_compare_expr (l_start, r_start) == 1 |
| && l_end && r_end && gfc_dep_compare_expr (l_end, r_end) == 1) |
| { |
| /* Check that the strides are the same. */ |
| if (!l_stride && !r_stride) |
| return GFC_DEP_FORWARD; |
| if (l_stride && r_stride |
| && gfc_dep_compare_expr (l_stride, r_stride) == 0) |
| return GFC_DEP_FORWARD; |
| } |
| |
| return GFC_DEP_OVERLAP; |
| } |
| |
| |
| /* Determines overlapping for a single element and a section. */ |
| |
| static gfc_dependency |
| gfc_check_element_vs_section( gfc_ref * lref, gfc_ref * rref, int n) |
| { |
| gfc_array_ref *ref; |
| gfc_expr *elem; |
| gfc_expr *start; |
| gfc_expr *end; |
| gfc_expr *stride; |
| int s; |
| |
| elem = lref->u.ar.start[n]; |
| if (!elem) |
| return GFC_DEP_OVERLAP; |
| |
| ref = &rref->u.ar; |
| start = ref->start[n] ; |
| end = ref->end[n] ; |
| stride = ref->stride[n]; |
| |
| if (!start && IS_ARRAY_EXPLICIT (ref->as)) |
| start = ref->as->lower[n]; |
| if (!end && IS_ARRAY_EXPLICIT (ref->as)) |
| end = ref->as->upper[n]; |
| |
| /* Determine whether the stride is positive or negative. */ |
| if (!stride) |
| s = 1; |
| else if (stride->expr_type == EXPR_CONSTANT |
| && stride->ts.type == BT_INTEGER) |
| s = mpz_sgn (stride->value.integer); |
| else |
| s = -2; |
| |
| /* Stride should never be zero. */ |
| if (s == 0) |
| return GFC_DEP_OVERLAP; |
| |
| /* Positive strides. */ |
| if (s == 1) |
| { |
| /* Check for elem < lower. */ |
| if (start && gfc_dep_compare_expr (elem, start) == -1) |
| return GFC_DEP_NODEP; |
| /* Check for elem > upper. */ |
| if (end && gfc_dep_compare_expr (elem, end) == 1) |
| return GFC_DEP_NODEP; |
| |
| if (start && end) |
| { |
| s = gfc_dep_compare_expr (start, end); |
| /* Check for an empty range. */ |
| if (s == 1) |
| return GFC_DEP_NODEP; |
| if (s == 0 && gfc_dep_compare_expr (elem, start) == 0) |
| return GFC_DEP_EQUAL; |
| } |
| } |
| /* Negative strides. */ |
| else if (s == -1) |
| { |
| /* Check for elem > upper. */ |
| if (end && gfc_dep_compare_expr (elem, start) == 1) |
| return GFC_DEP_NODEP; |
| /* Check for elem < lower. */ |
| if (start && gfc_dep_compare_expr (elem, end) == -1) |
| return GFC_DEP_NODEP; |
| |
| if (start && end) |
| { |
| s = gfc_dep_compare_expr (start, end); |
| /* Check for an empty range. */ |
| if (s == -1) |
| return GFC_DEP_NODEP; |
| if (s == 0 && gfc_dep_compare_expr (elem, start) == 0) |
| return GFC_DEP_EQUAL; |
| } |
| } |
| /* Unknown strides. */ |
| else |
| { |
| if (!start || !end) |
| return GFC_DEP_OVERLAP; |
| s = gfc_dep_compare_expr (start, end); |
| if (s == -2) |
| return GFC_DEP_OVERLAP; |
| /* Assume positive stride. */ |
| if (s == -1) |
| { |
| /* Check for elem < lower. */ |
| if (gfc_dep_compare_expr (elem, start) == -1) |
| return GFC_DEP_NODEP; |
| /* Check for elem > upper. */ |
| if (gfc_dep_compare_expr (elem, end) == 1) |
| return GFC_DEP_NODEP; |
| } |
| /* Assume negative stride. */ |
| else if (s == 1) |
| { |
| /* Check for elem > upper. */ |
| if (gfc_dep_compare_expr (elem, start) == 1) |
| return GFC_DEP_NODEP; |
| /* Check for elem < lower. */ |
| if (gfc_dep_compare_expr (elem, end) == -1) |
| return GFC_DEP_NODEP; |
| } |
| /* Equal bounds. */ |
| else if (s == 0) |
| { |
| s = gfc_dep_compare_expr (elem, start); |
| if (s == 0) |
| return GFC_DEP_EQUAL; |
| if (s == 1 || s == -1) |
| return GFC_DEP_NODEP; |
| } |
| } |
| |
| return GFC_DEP_OVERLAP; |
| } |
| |
| |
| /* Traverse expr, checking all EXPR_VARIABLE symbols for their |
| forall_index attribute. Return true if any variable may be |
| being used as a FORALL index. Its safe to pessimistically |
| return true, and assume a dependency. */ |
| |
| static bool |
| contains_forall_index_p (gfc_expr * expr) |
| { |
| gfc_actual_arglist *arg; |
| gfc_constructor *c; |
| gfc_ref *ref; |
| int i; |
| |
| if (!expr) |
| return false; |
| |
| switch (expr->expr_type) |
| { |
| case EXPR_VARIABLE: |
| if (expr->symtree->n.sym->forall_index) |
| return true; |
| break; |
| |
| case EXPR_OP: |
| if (contains_forall_index_p (expr->value.op.op1) |
| || contains_forall_index_p (expr->value.op.op2)) |
| return true; |
| break; |
| |
| case EXPR_FUNCTION: |
| for (arg = expr->value.function.actual; arg; arg = arg->next) |
| if (contains_forall_index_p (arg->expr)) |
| return true; |
| break; |
| |
| case EXPR_CONSTANT: |
| case EXPR_NULL: |
| case EXPR_SUBSTRING: |
| break; |
| |
| case EXPR_STRUCTURE: |
| case EXPR_ARRAY: |
| for (c = expr->value.constructor; c; c = c->next) |
| if (contains_forall_index_p (c->expr)) |
| return true; |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| for (ref = expr->ref; ref; ref = ref->next) |
| switch (ref->type) |
| { |
| case REF_ARRAY: |
| for (i = 0; i < ref->u.ar.dimen; i++) |
| if (contains_forall_index_p (ref->u.ar.start[i]) |
| || contains_forall_index_p (ref->u.ar.end[i]) |
| || contains_forall_index_p (ref->u.ar.stride[i])) |
| return true; |
| break; |
| |
| case REF_COMPONENT: |
| break; |
| |
| case REF_SUBSTRING: |
| if (contains_forall_index_p (ref->u.ss.start) |
| || contains_forall_index_p (ref->u.ss.end)) |
| return true; |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| |
| return false; |
| } |
| |
| /* Determines overlapping for two single element array references. */ |
| |
| static gfc_dependency |
| gfc_check_element_vs_element (gfc_ref * lref, gfc_ref * rref, int n) |
| { |
| gfc_array_ref l_ar; |
| gfc_array_ref r_ar; |
| gfc_expr *l_start; |
| gfc_expr *r_start; |
| int i; |
| |
| l_ar = lref->u.ar; |
| r_ar = rref->u.ar; |
| l_start = l_ar.start[n] ; |
| r_start = r_ar.start[n] ; |
| i = gfc_dep_compare_expr (r_start, l_start); |
| if (i == 0) |
| return GFC_DEP_EQUAL; |
| |
| /* Treat two scalar variables as potentially equal. This allows |
| us to prove that a(i,:) and a(j,:) have no dependency. See |
| Gerald Roth, "Evaluation of Array Syntax Dependence Analysis", |
| Proceedings of the International Conference on Parallel and |
| Distributed Processing Techniques and Applications (PDPTA2001), |
| Las Vegas, Nevada, June 2001. */ |
| /* However, we need to be careful when either scalar expression |
| contains a FORALL index, as these can potentially change value |
| during the scalarization/traversal of this array reference. */ |
| if (contains_forall_index_p (r_start) |
| || contains_forall_index_p (l_start)) |
| return GFC_DEP_OVERLAP; |
| |
| if (i != -2) |
| return GFC_DEP_NODEP; |
| return GFC_DEP_EQUAL; |
| } |
| |
| |
| /* Determine if an array ref, usually an array section specifies the |
| entire array. */ |
| |
| bool |
| gfc_full_array_ref_p (gfc_ref *ref) |
| { |
| int i; |
| |
| if (ref->type != REF_ARRAY) |
| return false; |
| if (ref->u.ar.type == AR_FULL) |
| return true; |
| if (ref->u.ar.type != AR_SECTION) |
| return false; |
| if (ref->next) |
| return false; |
| |
| for (i = 0; i < ref->u.ar.dimen; i++) |
| { |
| /* Check the lower bound. */ |
| if (ref->u.ar.start[i] |
| && (!ref->u.ar.as |
| || !ref->u.ar.as->lower[i] |
| || gfc_dep_compare_expr (ref->u.ar.start[i], |
| ref->u.ar.as->lower[i]))) |
| return false; |
| /* Check the upper bound. */ |
| if (ref->u.ar.end[i] |
| && (!ref->u.ar.as |
| || !ref->u.ar.as->upper[i] |
| || gfc_dep_compare_expr (ref->u.ar.end[i], |
| ref->u.ar.as->upper[i]))) |
| return false; |
| /* Check the stride. */ |
| if (ref->u.ar.stride[i] |
| && !gfc_expr_is_one (ref->u.ar.stride[i], 0)) |
| return false; |
| } |
| return true; |
| } |
| |
| |
| /* Finds if two array references are overlapping or not. |
| Return value |
| 1 : array references are overlapping. |
| 0 : array references are identical or not overlapping. */ |
| |
| int |
| gfc_dep_resolver (gfc_ref * lref, gfc_ref * rref) |
| { |
| int n; |
| gfc_dependency fin_dep; |
| gfc_dependency this_dep; |
| |
| |
| fin_dep = GFC_DEP_ERROR; |
| /* Dependencies due to pointers should already have been identified. |
| We only need to check for overlapping array references. */ |
| |
| while (lref && rref) |
| { |
| /* We're resolving from the same base symbol, so both refs should be |
| the same type. We traverse the reference chain intil we find ranges |
| that are not equal. */ |
| gcc_assert (lref->type == rref->type); |
| switch (lref->type) |
| { |
| case REF_COMPONENT: |
| /* The two ranges can't overlap if they are from different |
| components. */ |
| if (lref->u.c.component != rref->u.c.component) |
| return 0; |
| break; |
| |
| case REF_SUBSTRING: |
| /* Substring overlaps are handled by the string assignment code. */ |
| return 0; |
| |
| case REF_ARRAY: |
| if (lref->u.ar.dimen != rref->u.ar.dimen) |
| { |
| if (lref->u.ar.type == AR_FULL) |
| fin_dep = gfc_full_array_ref_p (rref) ? GFC_DEP_EQUAL |
| : GFC_DEP_OVERLAP; |
| else if (rref->u.ar.type == AR_FULL) |
| fin_dep = gfc_full_array_ref_p (lref) ? GFC_DEP_EQUAL |
| : GFC_DEP_OVERLAP; |
| else |
| return 1; |
| break; |
| } |
| |
| for (n=0; n < lref->u.ar.dimen; n++) |
| { |
| /* Assume dependency when either of array reference is vector |
| subscript. */ |
| if (lref->u.ar.dimen_type[n] == DIMEN_VECTOR |
| || rref->u.ar.dimen_type[n] == DIMEN_VECTOR) |
| return 1; |
| if (lref->u.ar.dimen_type[n] == DIMEN_RANGE |
| && rref->u.ar.dimen_type[n] == DIMEN_RANGE) |
| this_dep = gfc_check_section_vs_section (lref, rref, n); |
| else if (lref->u.ar.dimen_type[n] == DIMEN_ELEMENT |
| && rref->u.ar.dimen_type[n] == DIMEN_RANGE) |
| this_dep = gfc_check_element_vs_section (lref, rref, n); |
| else if (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT |
| && lref->u.ar.dimen_type[n] == DIMEN_RANGE) |
| this_dep = gfc_check_element_vs_section (rref, lref, n); |
| else |
| { |
| gcc_assert (rref->u.ar.dimen_type[n] == DIMEN_ELEMENT |
| && lref->u.ar.dimen_type[n] == DIMEN_ELEMENT); |
| this_dep = gfc_check_element_vs_element (rref, lref, n); |
| } |
| |
| /* If any dimension doesn't overlap, we have no dependency. */ |
| if (this_dep == GFC_DEP_NODEP) |
| return 0; |
| |
| /* Overlap codes are in order of priority. We only need to |
| know the worst one.*/ |
| if (this_dep > fin_dep) |
| fin_dep = this_dep; |
| } |
| /* Exactly matching and forward overlapping ranges don't cause a |
| dependency. */ |
| if (fin_dep < GFC_DEP_OVERLAP) |
| return 0; |
| |
| /* Keep checking. We only have a dependency if |
| subsequent references also overlap. */ |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| lref = lref->next; |
| rref = rref->next; |
| } |
| |
| /* If we haven't seen any array refs then something went wrong. */ |
| gcc_assert (fin_dep != GFC_DEP_ERROR); |
| |
| /* Assume the worst if we nest to different depths. */ |
| if (lref || rref) |
| return 1; |
| |
| return fin_dep == GFC_DEP_OVERLAP; |
| } |
| |