Re: [PATCH] PR fortran/83998 -- fix dot_product on 0-sized arrays

[Thomas Koenig]

Hi Steve,

I have a couple of questions before I have to hurry off to work:

First, why is

@@ -2253,22 +2253,19 @@ gfc_simplify_dim (gfc_expr *x, gfc_expr *y)
  gfc_expr*
  gfc_simplify_dot_product (gfc_expr *vector_a, gfc_expr *vector_b)
  {
+  /* If vector_a is a zero-sized array, the result is 0 for INTEGER,
+     REAL, and COMPLEX types and .false. for LOGICAL.  */
+  if (vector_a->shape && mpz_get_si (vector_a->shape[0]) == 0)
+    {
+      if (vector_a->ts.type == BT_LOGICAL)
+       return gfc_get_logical_expr (gfc_default_logical_kind, NULL, false);
+      else
+       return gfc_get_int_expr (gfc_default_integer_kind, NULL, 0);
+    }

in front of

-  gfc_expr temp;
-
    if (!is_constant_array_expr (vector_a)
        || !is_constant_array_expr (vector_b))
      return NULL;

and / or why is the test only done for one variable?

Second, why do you remove this

-  temp.value.op.op = INTRINSIC_NONE;
-  temp.value.op.op1 = vector_a;
-  temp.value.op.op2 = vector_b;
-  gfc_type_convert_binary (&temp, 1);

block of code? What would happen for code like

  integer, dimension(2), parameter :: a = [ 1,2]
  real, dimension(2), parameter :: b = [1.0,2.0]
  real, parameter :: c = dot_product(a,b)

?

Regards

        Thomas