/* Dependency analysis
- Copyright (C) 2000, 2001, 2002, 2005, 2006, 2007
+ Copyright (C) 2000, 2001, 2002, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
Contributed by Paul Brook <paul@nowt.org>
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
+Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* dependency.c -- Expression dependency analysis code. */
/* There's probably quite a bit of duplication in this file. We currently
if dependencies. Ideally these would probably be merged. */
#include "config.h"
+#include "system.h"
#include "gfortran.h"
#include "dependency.h"
+#include "constructor.h"
+#include "arith.h"
/* static declarations */
/* Enums */
{
GFC_DEP_ERROR,
GFC_DEP_EQUAL, /* Identical Ranges. */
- GFC_DEP_FORWARD, /* eg. a(1:3), a(2:4). */
+ GFC_DEP_FORWARD, /* e.g., a(1:3) = a(2:4). */
+ GFC_DEP_BACKWARD, /* e.g. a(2:4) = a(1:3). */
GFC_DEP_OVERLAP, /* May overlap in some other way. */
GFC_DEP_NODEP /* Distinct ranges. */
}
/* Macros */
#define IS_ARRAY_EXPLICIT(as) ((as->type == AS_EXPLICIT ? 1 : 0))
+/* Forward declarations */
+
+static gfc_dependency check_section_vs_section (gfc_array_ref *,
+ gfc_array_ref *, int);
/* 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. */
return mpz_cmp_si (expr->value.integer, 1) == 0;
}
+/* Check if two array references are known to be identical. Calls
+ gfc_dep_compare_expr if necessary for comparing array indices. */
+
+static bool
+identical_array_ref (gfc_array_ref *a1, gfc_array_ref *a2)
+{
+ int i;
+
+ if (a1->type == AR_FULL && a2->type == AR_FULL)
+ return true;
+
+ if (a1->type == AR_SECTION && a2->type == AR_SECTION)
+ {
+ gcc_assert (a1->dimen == a2->dimen);
+
+ for ( i = 0; i < a1->dimen; i++)
+ {
+ /* TODO: Currently, we punt on an integer array as an index. */
+ if (a1->dimen_type[i] != DIMEN_RANGE
+ || a2->dimen_type[i] != DIMEN_RANGE)
+ return false;
+
+ if (check_section_vs_section (a1, a2, i) != GFC_DEP_EQUAL)
+ return false;
+ }
+ return true;
+ }
+
+ if (a1->type == AR_ELEMENT && a2->type == AR_ELEMENT)
+ {
+ gcc_assert (a1->dimen == a2->dimen);
+ for (i = 0; i < a1->dimen; i++)
+ {
+ if (gfc_dep_compare_expr (a1->start[i], a2->start[i]) != 0)
+ return false;
+ }
+ return true;
+ }
+ return false;
+}
+
+
-/* 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. */
+/* Return true for identical variables, checking for references if
+ necessary. Calls identical_array_ref for checking array sections. */
+
+static bool
+are_identical_variables (gfc_expr *e1, gfc_expr *e2)
+{
+ gfc_ref *r1, *r2;
+
+ if (e1->symtree->n.sym->attr.dummy && e2->symtree->n.sym->attr.dummy)
+ {
+ /* Dummy arguments: Only check for equal names. */
+ if (e1->symtree->n.sym->name != e2->symtree->n.sym->name)
+ return false;
+ }
+ else
+ {
+ /* Check for equal symbols. */
+ if (e1->symtree->n.sym != e2->symtree->n.sym)
+ return false;
+ }
+
+ /* Volatile variables should never compare equal to themselves. */
+
+ if (e1->symtree->n.sym->attr.volatile_)
+ return false;
+
+ r1 = e1->ref;
+ r2 = e2->ref;
+
+ while (r1 != NULL || r2 != NULL)
+ {
+
+ /* Assume the variables are not equal if one has a reference and the
+ other doesn't.
+ TODO: Handle full references like comparing a(:) to a.
+ */
+
+ if (r1 == NULL || r2 == NULL)
+ return false;
+
+ if (r1->type != r2->type)
+ return false;
+
+ switch (r1->type)
+ {
+
+ case REF_ARRAY:
+ if (!identical_array_ref (&r1->u.ar, &r2->u.ar))
+ return false;
+
+ break;
+
+ case REF_COMPONENT:
+ if (r1->u.c.component != r2->u.c.component)
+ return false;
+ break;
+
+ case REF_SUBSTRING:
+ if (gfc_dep_compare_expr (r1->u.ss.start, r2->u.ss.start) != 0
+ || gfc_dep_compare_expr (r1->u.ss.end, r2->u.ss.end) != 0)
+ return false;
+ break;
+
+ default:
+ gfc_internal_error ("are_identical_variables: Bad type");
+ }
+ r1 = r1->next;
+ r2 = r2->next;
+ }
+ return true;
+}
+
+/* Compare two functions for equality. Returns 0 if e1==e2, -2 otherwise. If
+ impure_ok is false, only return 0 for pure functions. */
+
+int
+gfc_dep_compare_functions (gfc_expr *e1, gfc_expr *e2, bool impure_ok)
+{
+
+ gfc_actual_arglist *args1;
+ gfc_actual_arglist *args2;
+
+ if (e1->expr_type != EXPR_FUNCTION || e2->expr_type != EXPR_FUNCTION)
+ return -2;
+
+ if ((e1->value.function.esym && e2->value.function.esym
+ && e1->value.function.esym == e2->value.function.esym
+ && (e1->value.function.esym->result->attr.pure || impure_ok))
+ || (e1->value.function.isym && e2->value.function.isym
+ && e1->value.function.isym == e2->value.function.isym
+ && (e1->value.function.isym->pure || impure_ok)))
+ {
+ args1 = e1->value.function.actual;
+ args2 = e2->value.function.actual;
+
+ /* Compare the argument lists for equality. */
+ while (args1 && args2)
+ {
+ /* Bitwise xor, since C has no non-bitwise xor operator. */
+ if ((args1->expr == NULL) ^ (args2->expr == NULL))
+ return -2;
+
+ if (args1->expr != NULL && args2->expr != NULL
+ && gfc_dep_compare_expr (args1->expr, args2->expr) != 0)
+ return -2;
+
+ args1 = args1->next;
+ args2 = args2->next;
+ }
+ return (args1 || args2) ? -2 : 0;
+ }
+ else
+ return -2;
+}
+
+/* Compare two expressions. Return values:
+ * +1 if e1 > e2
+ * 0 if e1 == e2
+ * -1 if e1 < e2
+ * -2 if the relationship could not be determined
+ * -3 if e1 /= e2, but we cannot tell which one is larger. */
int
gfc_dep_compare_expr (gfc_expr *e1, gfc_expr *e2)
gfc_actual_arglist *args1;
gfc_actual_arglist *args2;
int i;
+ gfc_expr *n1, *n2;
+
+ n1 = NULL;
+ n2 = NULL;
+
+ /* Remove any integer conversion functions to larger types. */
+ if (e1->expr_type == EXPR_FUNCTION && e1->value.function.isym
+ && e1->value.function.isym->id == GFC_ISYM_CONVERSION
+ && e1->ts.type == BT_INTEGER)
+ {
+ args1 = e1->value.function.actual;
+ if (args1->expr->ts.type == BT_INTEGER
+ && e1->ts.kind > args1->expr->ts.kind)
+ n1 = args1->expr;
+ }
+
+ if (e2->expr_type == EXPR_FUNCTION && e2->value.function.isym
+ && e2->value.function.isym->id == GFC_ISYM_CONVERSION
+ && e2->ts.type == BT_INTEGER)
+ {
+ args2 = e2->value.function.actual;
+ if (args2->expr->ts.type == BT_INTEGER
+ && e2->ts.kind > args2->expr->ts.kind)
+ n2 = args2->expr;
+ }
+ if (n1 != NULL)
+ {
+ if (n2 != NULL)
+ return gfc_dep_compare_expr (n1, n2);
+ else
+ return gfc_dep_compare_expr (n1, e2);
+ }
+ else
+ {
+ if (n2 != NULL)
+ return gfc_dep_compare_expr (e1, n2);
+ }
+
if (e1->expr_type == EXPR_OP
- && (e1->value.op.operator == INTRINSIC_UPLUS
- || e1->value.op.operator == INTRINSIC_PARENTHESES))
+ && (e1->value.op.op == INTRINSIC_UPLUS
+ || e1->value.op.op == 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))
+ && (e2->value.op.op == INTRINSIC_UPLUS
+ || e2->value.op.op == INTRINSIC_PARENTHESES))
return gfc_dep_compare_expr (e1, e2->value.op.op1);
- if (e1->expr_type == EXPR_OP && e1->value.op.operator == INTRINSIC_PLUS)
+ if (e1->expr_type == EXPR_OP && e1->value.op.op == INTRINSIC_PLUS)
{
/* Compare X+C vs. X. */
if (e1->value.op.op2->expr_type == EXPR_CONSTANT
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)
+ if (e2->expr_type == EXPR_OP && e2->value.op.op == INTRINSIC_PLUS)
{
int l, r;
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)
+ if (l == 0 && r > -2)
return r;
- if (l != -2 && r == 0)
+ if (l > -2 && r == 0)
return l;
if (l == 1 && r == 1)
return 1;
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)
+ if (l == 0 && r > -2)
return r;
- if (l != -2 && r == 0)
+ if (l > -2 && r == 0)
return l;
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->expr_type == EXPR_OP && e2->value.op.op == INTRINSIC_PLUS)
{
if (e2->value.op.op2->expr_type == EXPR_CONSTANT
&& e2->value.op.op2->ts.type == BT_INTEGER
}
/* Compare X-C vs. X. */
- if (e1->expr_type == EXPR_OP && e1->value.op.operator == INTRINSIC_MINUS)
+ if (e1->expr_type == EXPR_OP && e1->value.op.op == INTRINSIC_MINUS)
{
if (e1->value.op.op2->expr_type == EXPR_CONSTANT
&& e1->value.op.op2->ts.type == BT_INTEGER
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)
+ if (e2->expr_type == EXPR_OP && e2->value.op.op == INTRINSIC_MINUS)
{
int l, r;
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)
+ if (l > -2 && r == 0)
return l;
- if (l == 0 && r != -2)
+ if (l == 0 && r > -2)
return -r;
if (l == 1 && r == -1)
return 1;
}
}
+ /* Compare A // B vs. C // D. */
+
+ if (e1->expr_type == EXPR_OP && e1->value.op.op == INTRINSIC_CONCAT
+ && e2->expr_type == EXPR_OP && e2->value.op.op == INTRINSIC_CONCAT)
+ {
+ 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 <= -2)
+ return l;
+
+ if (l == 0)
+ {
+ /* Watch out for 'A ' // x vs. 'A' // x. */
+ gfc_expr *e1_left = e1->value.op.op1;
+ gfc_expr *e2_left = e2->value.op.op1;
+
+ if (e1_left->expr_type == EXPR_CONSTANT
+ && e2_left->expr_type == EXPR_CONSTANT
+ && e1_left->value.character.length
+ != e2_left->value.character.length)
+ return -2;
+ else
+ return r;
+ }
+ else
+ {
+ if (l != 0)
+ return l;
+ else
+ return r;
+ }
+ }
+
/* Compare X vs. X-C. */
- if (e2->expr_type == EXPR_OP && e2->value.op.operator == INTRINSIC_MINUS)
+ if (e2->expr_type == EXPR_OP && e2->value.op.op == INTRINSIC_MINUS)
{
if (e2->value.op.op2->expr_type == EXPR_CONSTANT
&& e2->value.op.op2->ts.type == BT_INTEGER
}
if (e1->expr_type != e2->expr_type)
- return -2;
+ return -3;
switch (e1->expr_type)
{
case EXPR_CONSTANT:
+ /* Compare strings for equality. */
+ if (e1->ts.type == BT_CHARACTER && e2->ts.type == BT_CHARACTER)
+ return gfc_compare_string (e1, e2);
+
if (e1->ts.type != BT_INTEGER || e2->ts.type != BT_INTEGER)
return -2;
return 1;
case EXPR_VARIABLE:
- if (e1->ref || e2->ref)
- return -2;
- if (e1->symtree->n.sym == e2->symtree->n.sym)
+ if (are_identical_variables (e1, e2))
return 0;
- return -2;
+ else
+ return -3;
case EXPR_OP:
/* Intrinsic operators are the same if their operands are the same. */
- if (e1->value.op.operator != e2->value.op.operator)
+ if (e1->value.op.op != e2->value.op.op)
return -2;
if (e1->value.op.op2 == 0)
{
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? */
+ else if (e1->value.op.op == INTRINSIC_TIMES
+ && gfc_dep_compare_expr (e1->value.op.op1, e2->value.op.op2) == 0
+ && gfc_dep_compare_expr (e1->value.op.op2, e2->value.op.op1) == 0)
+ /* Commutativity of multiplication. */
+ return 0;
+
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;
- }
+ return gfc_dep_compare_functions (e1, e2, false);
+ break;
- /* 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. */
+/* Returns 1 if the two ranges are the same and 0 if they are not (or 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)
+static int
+is_same_range (gfc_array_ref *ar1, gfc_array_ref *ar2, int n)
{
gfc_expr *e1;
gfc_expr *e2;
if (e1 && !e2)
{
i = gfc_expr_is_one (e1, -1);
- if (i == -1)
- return def;
- else if (i == 0)
+ if (i == -1 || i == 0)
return 0;
}
else if (e2 && !e1)
{
i = gfc_expr_is_one (e2, -1);
- if (i == -1)
- return def;
- else if (i == 0)
+ if (i == -1 || i == 0)
return 0;
}
else if (e1 && e2)
{
i = gfc_dep_compare_expr (e1, e2);
- if (i == -2)
- return def;
- else if (i != 0)
+ if (i != 0)
return 0;
}
/* The strides match. */
/* Check we have values for both. */
if (!(e1 && e2))
- return def;
+ return 0;
i = gfc_dep_compare_expr (e1, e2);
- if (i == -2)
- return def;
- else if (i != 0)
+ if (i != 0)
return 0;
}
/* Check we have values for both. */
if (!(e1 && e2))
- return def;
+ return 0;
i = gfc_dep_compare_expr (e1, e2);
- if (i == -2)
- return def;
- else if (i != 0)
+ if (i != 0)
return 0;
}
if (expr->expr_type != EXPR_FUNCTION || !expr->value.function.isym)
return NULL;
- switch (expr->value.function.isym->generic_id)
+ switch (expr->value.function.isym->id)
{
case GFC_ISYM_TRANSPOSE:
return expr->value.function.actual->expr;
}
+static int
+gfc_is_data_pointer (gfc_expr *e)
+{
+ gfc_ref *ref;
+
+ if (e->expr_type != EXPR_VARIABLE && e->expr_type != EXPR_FUNCTION)
+ return 0;
+
+ /* No subreference if it is a function */
+ gcc_assert (e->expr_type == EXPR_VARIABLE || !e->ref);
+
+ if (e->symtree->n.sym->attr.pointer)
+ return 1;
+
+ for (ref = e->ref; ref; ref = ref->next)
+ if (ref->type == REF_COMPONENT && ref->u.c.component->attr.pointer)
+ return 1;
+
+ return 0;
+}
+
+
/* 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.
static int
gfc_check_argument_var_dependency (gfc_expr *var, sym_intent intent,
- gfc_expr *expr)
+ gfc_expr *expr, gfc_dep_check elemental)
{
+ gfc_expr *arg;
+
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));
+ /* In case of elemental subroutines, there is no dependency
+ between two same-range array references. */
+ if (gfc_ref_needs_temporary_p (expr->ref)
+ || gfc_check_dependency (var, expr, elemental == NOT_ELEMENTAL))
+ {
+ if (elemental == ELEM_DONT_CHECK_VARIABLE)
+ {
+ /* Too many false positive with pointers. */
+ if (!gfc_is_data_pointer (var) && !gfc_is_data_pointer (expr))
+ {
+ /* Elemental procedures forbid unspecified intents,
+ and we don't check dependencies for INTENT_IN args. */
+ gcc_assert (intent == INTENT_OUT || intent == INTENT_INOUT);
+
+ /* We are told not to check dependencies.
+ We do it, however, and issue a warning in case we find one.
+ If a dependency is found in the case
+ elemental == ELEM_CHECK_VARIABLE, we will generate
+ a temporary, so we don't need to bother the user. */
+ gfc_warning ("INTENT(%s) actual argument at %L might "
+ "interfere with actual argument at %L.",
+ intent == INTENT_OUT ? "OUT" : "INOUT",
+ &var->where, &expr->where);
+ }
+ return 0;
+ }
+ else
+ return 1;
+ }
+ return 0;
case EXPR_ARRAY:
return gfc_check_dependency (var, expr, 1);
case EXPR_FUNCTION:
- if (intent != INTENT_IN && expr->inline_noncopying_intrinsic)
+ if (intent != INTENT_IN)
{
- expr = gfc_get_noncopying_intrinsic_argument (expr);
- return gfc_check_argument_var_dependency (var, intent, expr);
+ arg = gfc_get_noncopying_intrinsic_argument (expr);
+ if (arg != NULL)
+ return gfc_check_argument_var_dependency (var, intent, arg,
+ NOT_ELEMENTAL);
+ }
+
+ if (elemental != NOT_ELEMENTAL)
+ {
+ if ((expr->value.function.esym
+ && expr->value.function.esym->attr.elemental)
+ || (expr->value.function.isym
+ && expr->value.function.isym->elemental))
+ return gfc_check_fncall_dependency (var, intent, NULL,
+ expr->value.function.actual,
+ ELEM_CHECK_VARIABLE);
+
+ if (gfc_inline_intrinsic_function_p (expr))
+ {
+ /* The TRANSPOSE case should have been caught in the
+ noncopying intrinsic case above. */
+ gcc_assert (expr->value.function.isym->id != GFC_ISYM_TRANSPOSE);
+
+ return gfc_check_fncall_dependency (var, intent, NULL,
+ expr->value.function.actual,
+ ELEM_CHECK_VARIABLE);
+ }
+ }
+ return 0;
+
+ case EXPR_OP:
+ /* In case of non-elemental procedures, there is no need to catch
+ dependencies, as we will make a temporary anyway. */
+ if (elemental)
+ {
+ /* If the actual arg EXPR is an expression, we need to catch
+ a dependency between variables in EXPR and VAR,
+ an intent((IN)OUT) variable. */
+ if (expr->value.op.op1
+ && gfc_check_argument_var_dependency (var, intent,
+ expr->value.op.op1,
+ ELEM_CHECK_VARIABLE))
+ return 1;
+ else if (expr->value.op.op2
+ && gfc_check_argument_var_dependency (var, intent,
+ expr->value.op.op2,
+ ELEM_CHECK_VARIABLE))
+ return 1;
}
return 0;
static int
gfc_check_argument_dependency (gfc_expr *other, sym_intent intent,
- gfc_expr *expr)
+ gfc_expr *expr, gfc_dep_check elemental)
{
switch (other->expr_type)
{
case EXPR_VARIABLE:
- return gfc_check_argument_var_dependency (other, intent, expr);
+ return gfc_check_argument_var_dependency (other, intent, expr, elemental);
case EXPR_FUNCTION:
- if (other->inline_noncopying_intrinsic)
- {
- other = gfc_get_noncopying_intrinsic_argument (other);
- return gfc_check_argument_dependency (other, INTENT_IN, expr);
- }
+ other = gfc_get_noncopying_intrinsic_argument (other);
+ if (other != NULL)
+ return gfc_check_argument_dependency (other, INTENT_IN, expr,
+ NOT_ELEMENTAL);
+
return 0;
default:
int
gfc_check_fncall_dependency (gfc_expr *other, sym_intent intent,
- gfc_symbol *fnsym, gfc_actual_arglist *actual)
+ gfc_symbol *fnsym, gfc_actual_arglist *actual,
+ gfc_dep_check elemental)
{
gfc_formal_arglist *formal;
gfc_expr *expr;
&& formal->sym->attr.intent == INTENT_IN)
continue;
- if (gfc_check_argument_dependency (other, intent, expr))
+ if (gfc_check_argument_dependency (other, intent, expr, elemental))
return 1;
}
/* Return 1 if e1 and e2 are equivalenced arrays, either
- directly or indirectly; ie. equivalence (a,b) for a and b
+ directly or indirectly; i.e., 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
|| !e2->symtree->n.sym->attr.in_equivalence|| !e1->rank || !e2->rank)
return 0;
+ if (e1->symtree->n.sym->ns
+ && e1->symtree->n.sym->ns != gfc_current_ns)
+ l = e1->symtree->n.sym->ns->equiv_lists;
+ else
+ l = gfc_current_ns->equiv_lists;
+
/* 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)
+ for (; l; l = l->next)
{
fl1 = NULL;
fl2 = NULL;
}
+/* Return true if there is no possibility of aliasing because of a type
+ mismatch between all the possible pointer references and the
+ potential target. Note that this function is asymmetric in the
+ arguments and so must be called twice with the arguments exchanged. */
+
+static bool
+check_data_pointer_types (gfc_expr *expr1, gfc_expr *expr2)
+{
+ gfc_component *cm1;
+ gfc_symbol *sym1;
+ gfc_symbol *sym2;
+ gfc_ref *ref1;
+ bool seen_component_ref;
+
+ if (expr1->expr_type != EXPR_VARIABLE
+ || expr1->expr_type != EXPR_VARIABLE)
+ return false;
+
+ sym1 = expr1->symtree->n.sym;
+ sym2 = expr2->symtree->n.sym;
+
+ /* Keep it simple for now. */
+ if (sym1->ts.type == BT_DERIVED && sym2->ts.type == BT_DERIVED)
+ return false;
+
+ if (sym1->attr.pointer)
+ {
+ if (gfc_compare_types (&sym1->ts, &sym2->ts))
+ return false;
+ }
+
+ /* This is a conservative check on the components of the derived type
+ if no component references have been seen. Since we will not dig
+ into the components of derived type components, we play it safe by
+ returning false. First we check the reference chain and then, if
+ no component references have been seen, the components. */
+ seen_component_ref = false;
+ if (sym1->ts.type == BT_DERIVED)
+ {
+ for (ref1 = expr1->ref; ref1; ref1 = ref1->next)
+ {
+ if (ref1->type != REF_COMPONENT)
+ continue;
+
+ if (ref1->u.c.component->ts.type == BT_DERIVED)
+ return false;
+
+ if ((sym2->attr.pointer || ref1->u.c.component->attr.pointer)
+ && gfc_compare_types (&ref1->u.c.component->ts, &sym2->ts))
+ return false;
+
+ seen_component_ref = true;
+ }
+ }
+
+ if (sym1->ts.type == BT_DERIVED && !seen_component_ref)
+ {
+ for (cm1 = sym1->ts.u.derived->components; cm1; cm1 = cm1->next)
+ {
+ if (cm1->ts.type == BT_DERIVED)
+ return false;
+
+ if ((sym2->attr.pointer || cm1->attr.pointer)
+ && gfc_compare_types (&cm1->ts, &sym2->ts))
+ return false;
+ }
+ }
+
+ return true;
+}
+
+
/* 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
int
gfc_check_dependency (gfc_expr *expr1, gfc_expr *expr2, bool identical)
{
- gfc_ref *ref;
- int n;
gfc_actual_arglist *actual;
+ gfc_constructor *c;
+ int n;
gcc_assert (expr1->expr_type == EXPR_VARIABLE);
/* 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 (gfc_is_data_pointer (expr1) || gfc_is_data_pointer (expr2))
+ {
+ if (check_data_pointer_types (expr1, expr2)
+ && check_data_pointer_types (expr2, expr1))
+ return 0;
- 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;
+ }
+ else
+ {
+ gfc_symbol *sym1 = expr1->symtree->n.sym;
+ gfc_symbol *sym2 = expr2->symtree->n.sym;
+ if (sym1->attr.target && sym2->attr.target
+ && ((sym1->attr.dummy && !sym1->attr.contiguous
+ && (!sym1->attr.dimension
+ || sym2->as->type == AS_ASSUMED_SHAPE))
+ || (sym2->attr.dummy && !sym2->attr.contiguous
+ && (!sym2->attr.dimension
+ || sym2->as->type == AS_ASSUMED_SHAPE))))
+ return 1;
+ }
/* Otherwise distinct symbols have no dependencies. */
return 0;
/* 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);
+ if (expr1->ref && expr2->ref)
+ return gfc_dep_resolver (expr1->ref, expr2->ref, NULL);
return 1;
case EXPR_FUNCTION:
- if (expr2->inline_noncopying_intrinsic)
+ if (gfc_get_noncopying_intrinsic_argument (expr2) != NULL)
identical = 1;
+
/* Remember possible differences between elemental and
transformational functions. All functions inside a FORALL
will be pure. */
return 0;
case EXPR_ARRAY:
- /* Probably ok in the majority of (constant) cases. */
- return 1;
+ /* Loop through the array constructor's elements. */
+ for (c = gfc_constructor_first (expr2->value.constructor);
+ c; c = gfc_constructor_next (c))
+ {
+ /* If this is an iterator, assume the worst. */
+ if (c->iterator)
+ return 1;
+ /* Avoid recursion in the common case. */
+ if (c->expr->expr_type == EXPR_CONSTANT)
+ continue;
+ if (gfc_check_dependency (expr1, c->expr, 1))
+ return 1;
+ }
+ return 0;
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)
+check_section_vs_section (gfc_array_ref *l_ar, gfc_array_ref *r_ar, int n)
{
- gfc_array_ref l_ar;
gfc_expr *l_start;
gfc_expr *l_end;
gfc_expr *l_stride;
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;
+ gfc_expr *one_expr;
int r_dir;
+ int stride_comparison;
+ int start_comparison;
- 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))
+ if (is_same_range (l_ar, r_ar, n))
return GFC_DEP_EQUAL;
- l_start = l_ar.start[n];
- l_end = l_ar.end[n];
- l_stride = l_ar.stride[n];
+ 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];
+ 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 (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 (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 (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];
+ 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)
if (l_dir == 0 || r_dir == 0)
return GFC_DEP_OVERLAP;
+ /* Determine the relationship between the strides. Set stride_comparison to
+ -2 if the dependency cannot be determined
+ -1 if l_stride < r_stride
+ 0 if l_stride == r_stride
+ 1 if l_stride > r_stride
+ as determined by gfc_dep_compare_expr. */
+
+ one_expr = gfc_get_int_expr (gfc_index_integer_kind, NULL, 1);
+
+ stride_comparison = gfc_dep_compare_expr (l_stride ? l_stride : one_expr,
+ r_stride ? r_stride : one_expr);
+
+ if (l_start && r_start)
+ start_comparison = gfc_dep_compare_expr (l_start, r_start);
+ else
+ start_comparison = -2;
+
+ free (one_expr);
+
/* Determine LHS upper and lower bounds. */
if (l_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)
+ /* Handle cases like x:y:2 vs. x+1:z:4 as GFC_DEP_NODEP.
+ There is no dependency if the remainder of
+ (l_start - r_start) / gcd(l_stride, r_stride) is
+ nonzero.
+ TODO:
+ - Handle cases where x is an expression.
+ - Cases like a(1:4:2) = a(2:3) are still not handled.
+ */
+
+#define IS_CONSTANT_INTEGER(a) ((a) && ((a)->expr_type == EXPR_CONSTANT) \
+ && (a)->ts.type == BT_INTEGER)
+
+ if (IS_CONSTANT_INTEGER(l_start) && IS_CONSTANT_INTEGER(r_start)
+ && IS_CONSTANT_INTEGER(l_stride) && IS_CONSTANT_INTEGER(r_stride))
+ {
+ mpz_t gcd, tmp;
+ int result;
+
+ mpz_init (gcd);
+ mpz_init (tmp);
+
+ mpz_gcd (gcd, l_stride->value.integer, r_stride->value.integer);
+ mpz_sub (tmp, l_start->value.integer, r_start->value.integer);
+
+ mpz_fdiv_r (tmp, tmp, gcd);
+ result = mpz_cmp_si (tmp, 0L);
+
+ mpz_clear (gcd);
+ mpz_clear (tmp);
+
+ if (result != 0)
+ return GFC_DEP_NODEP;
+ }
+
+#undef IS_CONSTANT_INTEGER
+
+ /* Check for forward dependencies x:y vs. x+1:z and x:y:z vs. x:y:z+1. */
+
+ if (l_dir == 1 && r_dir == 1 &&
+ (start_comparison == 0 || start_comparison == -1)
+ && (stride_comparison == 0 || stride_comparison == -1))
+ return GFC_DEP_FORWARD;
+
+ /* Check for forward dependencies x:y:-1 vs. x-1:z:-1 and
+ x:y:-1 vs. x:y:-2. */
+ if (l_dir == -1 && r_dir == -1 &&
+ (start_comparison == 0 || start_comparison == 1)
+ && (stride_comparison == 0 || stride_comparison == 1))
+ return GFC_DEP_FORWARD;
+
+ if (stride_comparison == 0 || stride_comparison == -1)
+ {
+ if (l_start && IS_ARRAY_EXPLICIT (l_ar->as))
+ {
+
+ /* Check for a(low:y:s) vs. a(z:x:s) or
+ a(low:y:s) vs. a(z:x:s+1) where a has a lower bound
+ of low, which is always at least a forward dependence. */
+
+ if (r_dir == 1
+ && gfc_dep_compare_expr (l_start, l_ar->as->lower[n]) == 0)
+ return GFC_DEP_FORWARD;
+ }
+ }
+
+ if (stride_comparison == 0 || stride_comparison == 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;
+ if (l_start && IS_ARRAY_EXPLICIT (l_ar->as))
+ {
+
+ /* Check for a(high:y:-s) vs. a(z:x:-s) or
+ a(high:y:-s vs. a(z:x:-s-1) where a has a higher bound
+ of high, which is always at least a forward dependence. */
+
+ if (r_dir == -1
+ && gfc_dep_compare_expr (l_start, l_ar->as->upper[n]) == 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)
+
+ if (stride_comparison == 0)
{
- /* 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;
+ /* From here, check for backwards dependencies. */
+ /* x+1:y vs. x:z. */
+ if (l_dir == 1 && r_dir == 1 && start_comparison == 1)
+ return GFC_DEP_BACKWARD;
+
+ /* x-1:y:-1 vs. x:z:-1. */
+ if (l_dir == -1 && r_dir == -1 && start_comparison == -1)
+ return GFC_DEP_BACKWARD;
}
return GFC_DEP_OVERLAP;
if (!start || !end)
return GFC_DEP_OVERLAP;
s = gfc_dep_compare_expr (start, end);
- if (s == -2)
+ if (s <= -2)
return GFC_DEP_OVERLAP;
/* Assume positive stride. */
if (s == -1)
case EXPR_STRUCTURE:
case EXPR_ARRAY:
- for (c = expr->value.constructor; c; c = c->next)
+ for (c = gfc_constructor_first (expr->value.constructor);
+ c; gfc_constructor_next (c))
if (contains_forall_index_p (c->expr))
return true;
break;
if (contains_forall_index_p (r_start) || contains_forall_index_p (l_start))
return GFC_DEP_OVERLAP;
- if (i != -2)
+ if (i > -2)
return GFC_DEP_NODEP;
return GFC_DEP_EQUAL;
}
/* Determine if an array ref, usually an array section specifies the
- entire array. */
+ entire array. In addition, if the second, pointer argument is
+ provided, the function will return true if the reference is
+ contiguous; eg. (:, 1) gives true but (1,:) gives false. */
bool
-gfc_full_array_ref_p (gfc_ref *ref)
+gfc_full_array_ref_p (gfc_ref *ref, bool *contiguous)
{
int i;
+ int n;
+ bool lbound_OK = true;
+ bool ubound_OK = true;
+
+ if (contiguous)
+ *contiguous = false;
if (ref->type != REF_ARRAY)
return false;
+
if (ref->u.ar.type == AR_FULL)
- return true;
+ {
+ if (contiguous)
+ *contiguous = true;
+ 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++)
{
+ /* If we have a single element in the reference, for the reference
+ to be full, we need to ascertain that the array has a single
+ element in this dimension and that we actually reference the
+ correct element. */
+ if (ref->u.ar.dimen_type[i] == DIMEN_ELEMENT)
+ {
+ /* This is unconditionally a contiguous reference if all the
+ remaining dimensions are elements. */
+ if (contiguous)
+ {
+ *contiguous = true;
+ for (n = i + 1; n < ref->u.ar.dimen; n++)
+ if (ref->u.ar.dimen_type[n] != DIMEN_ELEMENT)
+ *contiguous = false;
+ }
+
+ if (!ref->u.ar.as
+ || !ref->u.ar.as->lower[i]
+ || !ref->u.ar.as->upper[i]
+ || gfc_dep_compare_expr (ref->u.ar.as->lower[i],
+ ref->u.ar.as->upper[i])
+ || !ref->u.ar.start[i]
+ || gfc_dep_compare_expr (ref->u.ar.start[i],
+ ref->u.ar.as->lower[i]))
+ return false;
+ else
+ continue;
+ }
+
/* 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;
+ lbound_OK = 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;
+ ubound_OK = false;
/* Check the stride. */
+ if (ref->u.ar.stride[i]
+ && !gfc_expr_is_one (ref->u.ar.stride[i], 0))
+ return false;
+
+ /* This is unconditionally a contiguous reference as long as all
+ the subsequent dimensions are elements. */
+ if (contiguous)
+ {
+ *contiguous = true;
+ for (n = i + 1; n < ref->u.ar.dimen; n++)
+ if (ref->u.ar.dimen_type[n] != DIMEN_ELEMENT)
+ *contiguous = false;
+ }
+
+ if (!lbound_OK || !ubound_OK)
+ return false;
+ }
+ return true;
+}
+
+
+/* Determine if a full array is the same as an array section with one
+ variable limit. For this to be so, the strides must both be unity
+ and one of either start == lower or end == upper must be true. */
+
+static bool
+ref_same_as_full_array (gfc_ref *full_ref, gfc_ref *ref)
+{
+ int i;
+ bool upper_or_lower;
+
+ if (full_ref->type != REF_ARRAY)
+ return false;
+ if (full_ref->u.ar.type != AR_FULL)
+ return false;
+ if (ref->type != REF_ARRAY)
+ return false;
+ if (ref->u.ar.type != AR_SECTION)
+ return false;
+
+ for (i = 0; i < ref->u.ar.dimen; i++)
+ {
+ /* If we have a single element in the reference, we need to check
+ that the array has a single element and that we actually reference
+ the correct element. */
+ if (ref->u.ar.dimen_type[i] == DIMEN_ELEMENT)
+ {
+ if (!full_ref->u.ar.as
+ || !full_ref->u.ar.as->lower[i]
+ || !full_ref->u.ar.as->upper[i]
+ || gfc_dep_compare_expr (full_ref->u.ar.as->lower[i],
+ full_ref->u.ar.as->upper[i])
+ || !ref->u.ar.start[i]
+ || gfc_dep_compare_expr (ref->u.ar.start[i],
+ full_ref->u.ar.as->lower[i]))
+ return false;
+ }
+
+ /* Check the strides. */
+ if (full_ref->u.ar.stride[i] && !gfc_expr_is_one (full_ref->u.ar.stride[i], 0))
+ return false;
if (ref->u.ar.stride[i] && !gfc_expr_is_one (ref->u.ar.stride[i], 0))
return false;
+
+ upper_or_lower = false;
+ /* Check the lower bound. */
+ if (ref->u.ar.start[i]
+ && (ref->u.ar.as
+ && full_ref->u.ar.as->lower[i]
+ && gfc_dep_compare_expr (ref->u.ar.start[i],
+ full_ref->u.ar.as->lower[i]) == 0))
+ upper_or_lower = true;
+ /* Check the upper bound. */
+ if (ref->u.ar.end[i]
+ && (ref->u.ar.as
+ && full_ref->u.ar.as->upper[i]
+ && gfc_dep_compare_expr (ref->u.ar.end[i],
+ full_ref->u.ar.as->upper[i]) == 0))
+ upper_or_lower = true;
+ if (!upper_or_lower)
+ return false;
}
return true;
}
/* Finds if two array references are overlapping or not.
Return value
+ 2 : array references are overlapping but reversal of one or
+ more dimensions will clear the dependency.
1 : array references are overlapping.
0 : array references are identical or not overlapping. */
int
-gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref)
+gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_reverse *reverse)
{
int n;
gfc_dependency fin_dep;
gfc_dependency this_dep;
+ this_dep = GFC_DEP_ERROR;
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
+ the same type. We traverse the reference chain until we find ranges
that are not equal. */
gcc_assert (lref->type == rref->type);
switch (lref->type)
break;
case REF_SUBSTRING:
- /* Substring overlaps are handled by the string assignment code. */
- return 0;
+ /* Substring overlaps are handled by the string assignment code
+ if there is not an underlying dependency. */
+ return (fin_dep == GFC_DEP_OVERLAP) ? 1 : 0;
case REF_ARRAY:
+
+ if (ref_same_as_full_array (lref, rref))
+ return 0;
+
+ if (ref_same_as_full_array (rref, lref))
+ return 0;
+
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;
+ fin_dep = gfc_full_array_ref_p (rref, NULL) ? 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;
+ fin_dep = gfc_full_array_ref_p (lref, NULL) ? GFC_DEP_EQUAL
+ : GFC_DEP_OVERLAP;
else
return 1;
break;
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);
+ this_dep = check_section_vs_section (&lref->u.ar, &rref->u.ar, 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);
if (this_dep == GFC_DEP_NODEP)
return 0;
+ /* Now deal with the loop reversal logic: This only works on
+ ranges and is activated by setting
+ reverse[n] == GFC_ENABLE_REVERSE
+ The ability to reverse or not is set by previous conditions
+ in this dimension. If reversal is not activated, the
+ value GFC_DEP_BACKWARD is reset to GFC_DEP_OVERLAP. */
+ if (rref->u.ar.dimen_type[n] == DIMEN_RANGE
+ && lref->u.ar.dimen_type[n] == DIMEN_RANGE)
+ {
+ /* Set reverse if backward dependence and not inhibited. */
+ if (reverse && reverse[n] == GFC_ENABLE_REVERSE)
+ reverse[n] = (this_dep == GFC_DEP_BACKWARD) ?
+ GFC_REVERSE_SET : reverse[n];
+
+ /* Set forward if forward dependence and not inhibited. */
+ if (reverse && reverse[n] == GFC_ENABLE_REVERSE)
+ reverse[n] = (this_dep == GFC_DEP_FORWARD) ?
+ GFC_FORWARD_SET : reverse[n];
+
+ /* Flag up overlap if dependence not compatible with
+ the overall state of the expression. */
+ if (reverse && reverse[n] == GFC_REVERSE_SET
+ && this_dep == GFC_DEP_FORWARD)
+ {
+ reverse[n] = GFC_INHIBIT_REVERSE;
+ this_dep = GFC_DEP_OVERLAP;
+ }
+ else if (reverse && reverse[n] == GFC_FORWARD_SET
+ && this_dep == GFC_DEP_BACKWARD)
+ {
+ reverse[n] = GFC_INHIBIT_REVERSE;
+ this_dep = GFC_DEP_OVERLAP;
+ }
+
+ /* If no intention of reversing or reversing is explicitly
+ inhibited, convert backward dependence to overlap. */
+ if ((reverse == NULL && this_dep == GFC_DEP_BACKWARD)
+ || (reverse != NULL && reverse[n] == GFC_INHIBIT_REVERSE))
+ this_dep = GFC_DEP_OVERLAP;
+ }
+
/* Overlap codes are in order of priority. We only need to
know the worst one.*/
if (this_dep > fin_dep)
fin_dep = this_dep;
}
+
+ /* If this is an equal element, we have to keep going until we find
+ the "real" array reference. */
+ if (lref->u.ar.type == AR_ELEMENT
+ && rref->u.ar.type == AR_ELEMENT
+ && fin_dep == GFC_DEP_EQUAL)
+ break;
+
/* Exactly matching and forward overlapping ranges don't cause a
dependency. */
- if (fin_dep < GFC_DEP_OVERLAP)
+ if (fin_dep < GFC_DEP_BACKWARD)
return 0;
/* Keep checking. We only have a dependency if
return fin_dep == GFC_DEP_OVERLAP;
}
-
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