return 0;
}
+/* Dummy function for expression call back, for use when we
+ really don't want to do any walking. */
+
+static int
+dummy_expr_callback (gfc_expr **e ATTRIBUTE_UNUSED, int *walk_subtrees,
+ void *data ATTRIBUTE_UNUSED)
+{
+ *walk_subtrees = 0;
+ return 0;
+}
+
+/* Code callback function for converting
+ do while(a)
+ end do
+ into the equivalent
+ do
+ if (.not. a) exit
+ end do
+ This is because common function elimination would otherwise place the
+ temporary variables outside the loop. */
+
+static int
+convert_do_while (gfc_code **c, int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ gfc_code *co = *c;
+ gfc_code *c_if1, *c_if2, *c_exit;
+ gfc_code *loopblock;
+ gfc_expr *e_not, *e_cond;
+
+ if (co->op != EXEC_DO_WHILE)
+ return 0;
+
+ if (co->expr1 == NULL || co->expr1->expr_type == EXPR_CONSTANT)
+ return 0;
+
+ e_cond = co->expr1;
+
+ /* Generate the condition of the if statement, which is .not. the original
+ statement. */
+ e_not = gfc_get_expr ();
+ e_not->ts = e_cond->ts;
+ e_not->where = e_cond->where;
+ e_not->expr_type = EXPR_OP;
+ e_not->value.op.op = INTRINSIC_NOT;
+ e_not->value.op.op1 = e_cond;
+
+ /* Generate the EXIT statement. */
+ c_exit = XCNEW (gfc_code);
+ c_exit->op = EXEC_EXIT;
+ c_exit->ext.which_construct = co;
+ c_exit->loc = co->loc;
+
+ /* Generate the IF statement. */
+ c_if2 = XCNEW (gfc_code);
+ c_if2->op = EXEC_IF;
+ c_if2->expr1 = e_not;
+ c_if2->next = c_exit;
+ c_if2->loc = co->loc;
+
+ /* ... plus the one to chain it to. */
+ c_if1 = XCNEW (gfc_code);
+ c_if1->op = EXEC_IF;
+ c_if1->block = c_if2;
+ c_if1->loc = co->loc;
+
+ /* Make the DO WHILE loop into a DO block by replacing the condition
+ with a true constant. */
+ co->expr1 = gfc_get_logical_expr (gfc_default_integer_kind, &co->loc, true);
+
+ /* Hang the generated if statement into the loop body. */
+
+ loopblock = co->block->next;
+ co->block->next = c_if1;
+ c_if1->next = loopblock;
+
+ return 0;
+}
+
/* Optimize a namespace, including all contained namespaces. */
static void
current_ns = ns;
+ gfc_code_walker (&ns->code, convert_do_while, dummy_expr_callback, NULL);
gfc_code_walker (&ns->code, cfe_code, cfe_expr_0, NULL);
gfc_code_walker (&ns->code, optimize_code, optimize_expr, NULL);