DEC comparisons - allow Hollerith constants in comparisons.

The -fdec option enables the use of Hollerith comparisons in comparisons
with INTEGER, COMPLEX, REAL and CHARACTER expressions.

	Mark Eggleston  <mark.eggleston@codethink.com>
	Jim MacArthur  <jim.macarthur@codethink.co.uk>

	* gfortran.texi: Update Hollerith constants support for character types
	and use in comparisons.
	* invoke.texi: Tidy up list of options. Update description of
	-fdec-char-conversions.
	* resolve.c (is_character_based): New.
	(Convert_hollerith_to_character): New.  (convert_to_numeric): New.
	(resolve_operator): If both sides are character based and -fdec is
	enabled convert Hollerith to character. If an operand is Hollerith, the
	other is numeric and -fdec is enabled convert to numeric.
	(resolve_ordinary_assign): Add check for -fdec-char-conversions for
	assignment of character literals.

	Mark Eggleston <mark.eggleston@codethink.com>
	Jim MacArthur <jim.macarthur@codethink.co.uk>

	* gfortran.dg/dec-comparison-character_1.f90: New test.
	* gfortran.dg/dec-comparison-character_2.f90: New test.
	* gfortran.dg/dec-comparison-character_3.f90: New test.
	* gfortran.dg/dec-comparison-complex_1.f90: New test.
	* gfortran.dg/dec-comparison-complex_2.f90: New test.
	* gfortran.dg/dec-comparison-complex_3.f90: New test.
	* gfortran.dg/dec-comparison-int_1.f90: New test.
	* gfortran.dg/dec-comparison-int_2.f90: New test.
	* gfortran.dg/dec-comparison-int_3.f90: New test.
	* gfortran.dg/dec-comparison-real_1.f90: New test.
	* gfortran.dg/dec-comparison-real_2.f90: New test.
	* gfortran.dg/dec-comparison-real_3.f90: New test.
	* gfortran.dg/dec-comparison.f90: New test.


Co-Authored-By: Jim MacArthur <jim.macarthur@codethink.co.uk>

From-SVN: r278674

1 files changed, 53 insertions, 1 deletions

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 2371a9e..278dad3 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -3900,6 +3900,42 @@ impure_function_callback (gfc_expr **e, int *walk_subtrees ATTRIBUTE_UNUSED,
   return 0;
 }
 
+/* Return true if TYPE is character based, false otherwise.  */
+
+static int
+is_character_based (bt type)
+{
+  return type == BT_CHARACTER || type == BT_HOLLERITH;
+}
+
+
+/* If expression is a hollerith, convert it to character and issue a warning
+   for the conversion.  */
+
+static void
+convert_hollerith_to_character (gfc_expr *e)
+{
+  if (e->ts.type == BT_HOLLERITH)
+    {
+      gfc_typespec t;
+      gfc_clear_ts (&t);
+      t.type = BT_CHARACTER;
+      t.kind = e->ts.kind;
+      gfc_convert_type_warn (e, &t, 2, 1);
+    }
+}
+
+/* Convert to numeric and issue a warning for the conversion.  */
+
+static void
+convert_to_numeric (gfc_expr *a, gfc_expr *b)
+{
+  gfc_typespec t;
+  gfc_clear_ts (&t);
+  t.type = b->ts.type;
+  t.kind = b->ts.kind;
+  gfc_convert_type_warn (a, &t, 2, 1);
+}
 
 /* Resolve an operator expression node.  This can involve replacing the
    operation with a user defined function call.  */
@@ -4100,6 +4136,15 @@ resolve_operator (gfc_expr *e)
     case INTRINSIC_EQ_OS:
     case INTRINSIC_NE:
     case INTRINSIC_NE_OS:
+
+      if (flag_dec
+	  && is_character_based (op1->ts.type)
+	  && is_character_based (op2->ts.type))
+	{
+	  convert_hollerith_to_character (op1);
+	  convert_hollerith_to_character (op2);
+	}
+
       if (op1->ts.type == BT_CHARACTER && op2->ts.type == BT_CHARACTER
 	  && op1->ts.kind == op2->ts.kind)
 	{
@@ -4137,6 +4182,13 @@ resolve_operator (gfc_expr *e)
 	  if (op1->ts.type == BT_REAL && !gfc_boz2real (op2, op1->ts.kind))
 	    return false;
 	}
+      if (flag_dec
+	  && op1->ts.type == BT_HOLLERITH && gfc_numeric_ts (&op2->ts))
+	convert_to_numeric (op1, op2);
+
+      if (flag_dec
+	  && gfc_numeric_ts (&op1->ts) && op2->ts.type == BT_HOLLERITH)
+	convert_to_numeric (op2, op1);
 
       if (gfc_numeric_ts (&op1->ts) && gfc_numeric_ts (&op2->ts))
 	{
@@ -10693,7 +10745,7 @@ resolve_ordinary_assign (gfc_code *code, gfc_namespace *ns)
 
   if ((gfc_numeric_ts (&lhs->ts) || lhs->ts.type == BT_LOGICAL)
       && rhs->ts.type == BT_CHARACTER
-      && rhs->expr_type != EXPR_CONSTANT)
+      && (rhs->expr_type != EXPR_CONSTANT || !flag_dec_char_conversions))
     {
       /* Use of -fdec-char-conversions allows assignment of character data
 	 to non-character variables.  This not permited for nonconstant