[Bug fortran/32048] max / min and NaN

["fxcoudert at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #7 from fxcoudert at gcc dot gnu dot org  2007-07-28 13:49 -------
Here's a patch that yields results according to IEEE:

Index: f95-lang.c
===================================================================
--- f95-lang.c  (revision 126997)
+++ f95-lang.c  (working copy)
@@ -1004,6 +1004,11 @@ gfc_init_builtin_functions (void)
                      "malloc", false);
   DECL_IS_MALLOC (built_in_decls[BUILT_IN_MALLOC]) = 1;

+  tmp = tree_cons (NULL_TREE, void_type_node, void_list_node);
+  ftype = build_function_type (integer_type_node, tmp);
+  gfc_define_builtin ("__builtin_isnan", ftype, BUILT_IN_ISNAN,
+                     "__builtin_isnan", true);
+
 #define DEF_PRIMITIVE_TYPE(ENUM, VALUE) \
   builtin_types[(int) ENUM] = VALUE;
 #define DEF_FUNCTION_TYPE_0(ENUM, RETURN)              \
Index: trans-intrinsic.c
===================================================================
--- trans-intrinsic.c   (revision 126997)
+++ trans-intrinsic.c   (working copy)
@@ -1407,11 +1407,11 @@ gfc_conv_intrinsic_ttynam (gfc_se * se, 
 /* Get the minimum/maximum value of all the parameters.
     minmax (a1, a2, a3, ...)
     {
-      if (a2 .op. a1)
+      if (a2 .op. a1 || isnan(a1))
         mvar = a2;
       else
         mvar = a1;
-      if (a3 .op. mvar)
+      if (a3 .op. mvar || isnan(mvar))
         mvar = a3;
       ...
       return mvar
@@ -1487,7 +1487,7 @@ gfc_conv_intrinsic_minmax (gfc_se * se, 
   elsecase = build2_v (MODIFY_EXPR, mvar, limit);
   for (i = 1, argexpr = argexpr->next; i < nargs; i++)
     {
-      tree cond;
+      tree cond, isnan;

       val = args[i]; 

@@ -1509,6 +1509,11 @@ gfc_conv_intrinsic_minmax (gfc_se * se, 
       thencase = build2_v (MODIFY_EXPR, mvar, convert (type, val));

       tmp = build2 (op, boolean_type_node, convert (type, val), limit);
+      if (FLOAT_TYPE_P (TREE_TYPE (limit)))
+       {
+         isnan = build_call_expr (built_in_decls[BUILT_IN_ISNAN], 1, limit);
+         tmp = fold_build2 (TRUTH_OR_EXPR, boolean_type_node, tmp, isnan);
+       }
       tmp = build3_v (COND_EXPR, tmp, thencase, elsecase);

       if (cond != NULL_TREE)


With this, we generate calls to __builtin_isnan, which probably means slower
code is generated. Thus, we might want to make this dependent on whether
IEEE_ARITHMETIC is loaded or not, when we have this module implemented.


-- 

fxcoudert at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |wrong-code
   Last reconfirmed|0000-00-00 00:00:00         |2007-07-28 13:49:41
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32048