re PR fortran/64104 ([F2003][IEEE] Allow IEEE functions in specification expressions)

	PR fortran/64104

	* expr.c (gfc_check_init_expr): Allow some IEEE functions in
	constant expressions.
	(external_spec_function): Allow some IEEE functions in specification
	expressions.
	* simplify.c (gfc_simplify_ieee_selected_real_kind): Remove.
	(simplify_ieee_selected_real_kind, simplify_ieee_support,
	matches_ieee_function_name, gfc_simplify_ieee_functions): New
	functions.
	* gfortran.h (gfc_simplify_ieee_selected_real_kind): Remove
	prototype.
	(gfc_simplify_ieee_functions): Add prototype.

	* gfortran.dg/ieee/ieee_8.f90: New test.

From-SVN: r226723

1 files changed, 59 insertions, 14 deletions

diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
index f0fdfbd..124558e 100644
--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -5553,20 +5553,6 @@ gfc_simplify_selected_real_kind (gfc_expr *p, gfc_expr *q, gfc_expr *rdx)
 
 
 gfc_expr *
-gfc_simplify_ieee_selected_real_kind (gfc_expr *expr)
-{
-  gfc_actual_arglist *arg = expr->value.function.actual;
-  gfc_expr *p = arg->expr, *q = arg->next->expr,
-	   *rdx = arg->next->next->expr;
-
-  /* Currently, if IEEE is supported and this module is built, it means
-     all our floating-point types conform to IEEE. Hence, we simply handle
-     IEEE_SELECTED_REAL_KIND like SELECTED_REAL_KIND.  */
-  return gfc_simplify_selected_real_kind (p, q, rdx);
-}
-
-
-gfc_expr *
 gfc_simplify_set_exponent (gfc_expr *x, gfc_expr *i)
 {
   gfc_expr *result;
@@ -6955,3 +6941,62 @@ gfc_simplify_compiler_version (void)
   return gfc_get_character_expr (gfc_default_character_kind,
                                 &gfc_current_locus, buffer, len);
 }
+
+/* Simplification routines for intrinsics of IEEE modules.  */
+
+gfc_expr *
+simplify_ieee_selected_real_kind (gfc_expr *expr)
+{
+  gfc_actual_arglist *arg = expr->value.function.actual;
+  gfc_expr *p = arg->expr, *q = arg->next->expr,
+	   *rdx = arg->next->next->expr;
+
+  /* Currently, if IEEE is supported and this module is built, it means
+     all our floating-point types conform to IEEE. Hence, we simply handle
+     IEEE_SELECTED_REAL_KIND like SELECTED_REAL_KIND.  */
+  return gfc_simplify_selected_real_kind (p, q, rdx);
+}
+
+gfc_expr *
+simplify_ieee_support (gfc_expr *expr)
+{
+  /* We consider that if the IEEE modules are loaded, we have full support
+     for flags, halting and rounding, which are the three functions
+     (IEEE_SUPPORT_{FLAG,HALTING,ROUNDING}) allowed in constant
+     expressions. One day, we will need libgfortran to detect support and
+     communicate it back to us, allowing for partial support.  */
+
+  return gfc_get_logical_expr (gfc_default_logical_kind, &expr->where,
+			       true);
+}
+
+bool
+matches_ieee_function_name (gfc_symbol *sym, const char *name)
+{
+  int n = strlen(name);
+
+  if (!strncmp(sym->name, name, n))
+    return true;
+
+  /* If a generic was used and renamed, we need more work to find out.
+     Compare the specific name.  */
+  if (sym->generic && !strncmp(sym->generic->sym->name, name, n))
+    return true;
+
+  return false;
+}
+
+gfc_expr *
+gfc_simplify_ieee_functions (gfc_expr *expr)
+{
+  gfc_symbol* sym = expr->symtree->n.sym;
+
+  if (matches_ieee_function_name(sym, "ieee_selected_real_kind"))
+    return simplify_ieee_selected_real_kind (expr);
+  else if (matches_ieee_function_name(sym, "ieee_support_flag")
+	   || matches_ieee_function_name(sym, "ieee_support_halting")
+	   || matches_ieee_function_name(sym, "ieee_support_rounding"))
+    return simplify_ieee_support (expr);
+  else
+    return NULL;
+}