===================================================================
@@ -2232,6 +2232,7 @@ typedef struct
int flag_whole_file;
int flag_protect_parens;
int flag_realloc_lhs;
+ int flag_aggressive_function_elimination;
int fpe;
int rtcheck;
@@ -2865,6 +2866,7 @@ void gfc_global_used (gfc_gsymbol *, locus *);
gfc_namespace* gfc_build_block_ns (gfc_namespace *);
/* dependency.c */
+int gfc_dep_compare_functions (gfc_expr *, gfc_expr *, bool);
int gfc_dep_compare_expr (gfc_expr *, gfc_expr *);
/* check.c */
===================================================================
@@ -278,6 +278,10 @@ d
Fortran Joined
; Documented in common.opt
+faggressive-function-elimination
+Fortran
+Eliminate multiple function invokations also for impure functions
+
falign-commons
Fortran
Enable alignment of COMMON blocks
===================================================================
@@ -1468,6 +1468,18 @@ need to be in effect.
An allocatable left-hand side of an intrinsic assignment is automatically
(re)allocated if it is either unallocated or has a different shape. The
option is enabled by default except when @option{-std=f95} is given.
+
+@item -faggressive-function-elimination
+@opindex @code{faggressive-function-elimination}
+@cindex Elimination of functions with identical argument lists
+Functions with identical argument lists are eliminated within
+statements, regardless of whether these functions are marked
+@code{PURE} or not. For example, in
+@smallexample
+ a = f(b,c) + f(b,c)
+@end smallexample
+there will only be a single call to @code{f}.
+
@end table
@xref{Code Gen Options,,Options for Code Generation Conventions,
@@ -1475,7 +1487,6 @@ gcc,Using the GNU Compiler Collection (GCC)}, for
offered by the GBE
shared by @command{gfortran}, @command{gcc}, and other GNU compilers.
-
@c man end
@node Environment Variables
===================================================================
@@ -40,6 +40,21 @@ static bool optimize_trim (gfc_expr *);
static int count_arglist;
+/* Pointer to an array of gfc_expr ** we operate on, plus its size
+ and counter. */
+
+static gfc_expr ***expr_array;
+static int expr_size, expr_count;
+
+/* Pointer to the gfc_code we currently work on - to be able to insert
+ a statement before. */
+
+static gfc_code **current_code;
+
+/* The namespace we are currently dealing with. */
+
+gfc_namespace *current_ns;
+
/* Entry point - run all passes for a namespace. So far, only an
optimization pass is run. */
@@ -48,9 +63,16 @@ gfc_run_passes (gfc_namespace *ns)
{
if (optimize)
{
+ expr_size = 20;
+ expr_array = XNEWVEC(gfc_expr **, expr_size);
+
optimize_namespace (ns);
if (gfc_option.dump_fortran_optimized)
gfc_dump_parse_tree (ns, stdout);
+
+ /* FIXME: The following should be XDELETEVEC(expr_array);
+ but we cannot do that because it depends on free. */
+ gfc_free (expr_array);
}
}
@@ -106,11 +128,214 @@ optimize_expr (gfc_expr **e, int *walk_subtrees AT
return 0;
}
+
+/* Callback function for common function elimination, called from cfe_expr_0.
+ Put all eligible function expressions into expr_array. We can't do
+ allocatable functions. */
+
+static int
+cfe_register_funcs (gfc_expr **e, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ if ((*e)->expr_type != EXPR_FUNCTION)
+ return 0;
+
+ /* We don't do character functions (yet). */
+ if ((*e)->ts.type == BT_CHARACTER)
+ return 0;
+
+ /* If we don't know the shape at compile time, we do not create a temporary
+ variable to hold the intermediate result. FIXME: Change this later when
+ allocation on assignment works for intrinsics. */
+
+ if ((*e)->rank > 0 && (*e)->shape == NULL)
+ return 0;
+
+ /* Skip the test for pure functions if -faggressive-function-elimination
+ is specified. */
+ if ((*e)->value.function.esym)
+ {
+ if ((*e)->value.function.esym->attr.allocatable)
+ return 0;
+
+ /* Don't create an array temporary for elemental functions. */
+ if ((*e)->value.function.esym->attr.elemental && (*e)->rank > 0)
+ return 0;
+
+ /* Only eliminate potentially impure functions if the
+ user specifically requested it. */
+ if (!gfc_option.flag_aggressive_function_elimination
+ && !(*e)->value.function.esym->attr.pure
+ && !(*e)->value.function.esym->attr.implicit_pure)
+ return 0;
+ }
+
+ if ((*e)->value.function.isym)
+ {
+ /* Conversions are handled on the fly by the middle end,
+ transpose during trans-* stages. */
+ if ((*e)->value.function.isym->id == GFC_ISYM_CONVERSION
+ || (*e)->value.function.isym->id == GFC_ISYM_TRANSPOSE)
+ return 0;
+
+ /* Don't create an array temporary for elemental functions,
+ as this would be wasteful of memory.
+ FIXME: Create a scalar temporary during scalarization. */
+ if ((*e)->value.function.isym->elemental && (*e)->rank > 0)
+ return 0;
+
+ if (!(*e)->value.function.isym->pure)
+ return 0;
+ }
+
+ if (expr_count >= expr_size)
+ {
+ expr_size += expr_size;
+ expr_array = XRESIZEVEC(gfc_expr **, expr_array, expr_size);
+ }
+ expr_array[expr_count] = e;
+ expr_count ++;
+ return 0;
+}
+
+/* Returns a new expression (a variable) to be used in place of the old one,
+ with an an assignment statement before the current statement to set
+ the value of the variable. */
+
+static gfc_expr*
+create_var (gfc_expr * e)
+{
+ char name[GFC_MAX_SYMBOL_LEN +1];
+ static int num = 1;
+ gfc_symtree *symtree;
+ gfc_symbol *symbol;
+ gfc_expr *result;
+ gfc_code *n;
+ int i;
+
+ sprintf(name, "__var_%d",num++);
+ if (gfc_get_sym_tree (name, current_ns, &symtree, false) != 0)
+ gcc_unreachable ();
+
+ symbol = symtree->n.sym;
+ symbol->ts = e->ts;
+ symbol->as = gfc_get_array_spec ();
+ symbol->as->rank = e->rank;
+ symbol->as->type = AS_EXPLICIT;
+ for (i=0; i<e->rank; i++)
+ {
+ gfc_expr *p, *q;
+
+ p = gfc_get_constant_expr (BT_INTEGER, gfc_default_integer_kind,
+ &(e->where));
+ mpz_set_si (p->value.integer, 1);
+ symbol->as->lower[i] = p;
+
+ q = gfc_get_constant_expr (BT_INTEGER, gfc_index_integer_kind,
+ &(e->where));
+ mpz_set (q->value.integer, e->shape[i]);
+ symbol->as->upper[i] = q;
+ }
+
+ symbol->attr.flavor = FL_VARIABLE;
+ symbol->attr.referenced = 1;
+ symbol->attr.dimension = e->rank > 0;
+ gfc_commit_symbol (symbol);
+
+ result = gfc_get_expr ();
+ result->expr_type = EXPR_VARIABLE;
+ result->ts = e->ts;
+ result->rank = e->rank;
+ result->shape = gfc_copy_shape (e->shape, e->rank);
+ result->symtree = symtree;
+ result->where = e->where;
+ if (e->rank > 0)
+ {
+ result->ref = gfc_get_ref ();
+ result->ref->type = REF_ARRAY;
+ result->ref->u.ar.type = AR_FULL;
+ result->ref->u.ar.where = e->where;
+ result->ref->u.ar.as = symbol->as;
+ }
+
+ /* Generate the new assignment. */
+ n = XCNEW (gfc_code);
+ n->op = EXEC_ASSIGN;
+ n->loc = (*current_code)->loc;
+ n->next = *current_code;
+ n->expr1 = gfc_copy_expr (result);
+ n->expr2 = e;
+ *current_code = n;
+
+ return result;
+}
+
+/* Callback function for the code walker for doing common function
+ elimination. This builds up the list of functions in the expression
+ and goes through them to detect duplicates, which it then replaces
+ by variables. */
+
+static int
+cfe_expr_0 (gfc_expr **e, int *walk_subtrees,
+ void *data ATTRIBUTE_UNUSED)
+{
+ int i,j;
+ gfc_expr *newvar;
+
+ expr_count = 0;
+
+ gfc_expr_walker (e, cfe_register_funcs, NULL);
+
+ /* Walk backwards through all the functions to make sure we
+ catch the leaf functions first. */
+ for (i=expr_count-1; i>=1; i--)
+ {
+ /* Skip if the function has been replaced by a variable already. */
+ if ((*(expr_array[i]))->expr_type == EXPR_VARIABLE)
+ continue;
+
+ newvar = NULL;
+ for (j=i-1; j>=0; j--)
+ {
+ if (gfc_dep_compare_functions(*(expr_array[i]),
+ *(expr_array[j]), true) == 0)
+ {
+ if (newvar == NULL)
+ newvar = create_var (*(expr_array[i]));
+ gfc_free (*(expr_array[j]));
+ *(expr_array[j]) = gfc_copy_expr (newvar);
+ }
+ }
+ if (newvar)
+ *(expr_array[i]) = newvar;
+ }
+
+ /* We did all the necessary walking in this function. */
+ *walk_subtrees = 0;
+ return 0;
+}
+
+/* Callback function for common function elimination, called from
+ gfc_code_walker. This keeps track of the current code, in order
+ to insert statements as needed. */
+
+static int
+cfe_code (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ current_code = c;
+ return 0;
+}
+
/* Optimize a namespace, including all contained namespaces. */
static void
optimize_namespace (gfc_namespace *ns)
{
+
+ current_ns = ns;
+
+ gfc_code_walker (&ns->code, cfe_code, cfe_expr_0, NULL);
gfc_code_walker (&ns->code, optimize_code, optimize_expr, NULL);
for (ns = ns->contained; ns; ns = ns->sibling)
===================================================================
@@ -177,16 +177,60 @@ gfc_are_identical_variables (gfc_expr *e1, gfc_exp
return true;
}
+/* Compare two functions for equality. Only the first expression is known
+ to be a function. 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 (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 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)
{
+ int i;
+ gfc_expr *n1, *n2;
gfc_actual_arglist *args1;
gfc_actual_arglist *args2;
- int i;
- gfc_expr *n1, *n2;
n1 = NULL;
n2 = NULL;
@@ -399,36 +443,7 @@ gfc_dep_compare_expr (gfc_expr *e1, gfc_expr *e2)
return -2;
case EXPR_FUNCTION:
-
- /* PURE functions can be compared for argument equality. */
- if ((e1->value.function.esym && e2->value.function.esym
- && e1->value.function.esym == e2->value.function.esym
- && e1->value.function.esym->result->attr.pure)
- || (e1->value.function.isym && e2->value.function.isym
- && e1->value.function.isym == e2->value.function.isym
- && e1->value.function.isym->pure))
- {
- 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;
+ return gfc_dep_compare_functions (e1, e2, false);
break;
default:
===================================================================
@@ -150,6 +150,7 @@ gfc_init_options (unsigned int decoded_options_cou
gfc_option.flag_align_commons = 1;
gfc_option.flag_protect_parens = 1;
gfc_option.flag_realloc_lhs = -1;
+ gfc_option.flag_aggressive_function_elimination = 0;
gfc_option.fpe = 0;
gfc_option.rtcheck = 0;
@@ -972,6 +973,10 @@ gfc_handle_option (size_t scode, const char *arg,
gfc_option.flag_align_commons = value;
break;
+ case OPT_faggressive_function_elimination:
+ gfc_option.flag_aggressive_function_elimination = value;
+ break;
+
case OPT_fprotect_parens:
gfc_option.flag_protect_parens = value;
break;