Fix ICE caused by union types comparing equal to structures.

2016-09-30  Fritz Reese  <fritzoreese@gmail.com>

Fix ICE caused by union types comparing equal to structures.

	PR fortran/77782
	* gcc/fortran/interface.c (gfc_compare_derived_types): Use
	gfc_compare_union_types to compare union types.

	PR fortran/77782
	* gcc/testsuite/gfortran.dg/dec_structure_16.f90: New testcase.

From-SVN: r240651

gcc/fortran/ChangeLog

+2016-09-30  Fritz Reese  <fritzoreese@gmail.com>
+
+	PR fortran/77782
+	* interface.c (gfc_compare_derived_types): Use gfc_compare_union_types
+	to compare union types.
+
 2016-09-30  Andre Vehreschild  <vehre@gcc.gnu.org>
 
 	* trans-array.c (gfc_array_allocate): Use the token from coarray's

gcc/fortran/interface.c

@@ -589,6 +589,10 @@ gfc_compare_derived_types (gfc_symbol *derived1, gfc_symbol *derived2)
 
   gcc_assert (derived1 && derived2);
 
+  /* Compare UNION types specially.  */
+  if (derived1->attr.flavor == FL_UNION || derived2->attr.flavor == FL_UNION)
+    return gfc_compare_union_types (derived1, derived2);
+
   /* Special case for comparing derived types across namespaces.  If the
      true names and module names are the same and the module name is
      nonnull, then they are equal.  */

gcc/testsuite/ChangeLog

+2016-09-30  Fritz Reese  <fritzoreese@gmail.com>
+
+	PR fortran/77782
+	* gfortran.dg/dec_structure_16.f90: New testcase.
+
 2016-09-30  Andre Vehreschild  <vehre@gcc.gnu.org>
 
 	* gfortran.dg/coarray_allocate_10.f08: New test.

gcc/testsuite/gfortran.dg/dec_structure_16.f90

+! { dg-do compile }
+! { dg-options "-fdec-structure" }
+!
+! PR fortran/77782
+!
+! Test an ICE where a union might be considered equal to a structure,
+! causing the union's backend_decl to be replaced with that of the structure.
+!
+
+program p
+
+structure /s1/
+  union
+    map
+      integer(4) a
+      end map
+    map
+      real(4) b
+    end map
+  end union
+end structure
+
+structure /s2/
+  union ! regression: if this union == s1, we ICE in gfc_get_union_type
+    map
+      integer(2) x, y
+      integer(4) z
+    end map
+  end union
+end structure
+
+record /s1/ r1
+r1.a = 0
+
+end