compiler: Don't compare structs with blank non-comparable fields.

From-SVN: r205937

gcc/go/gofrontend/types.cc

@@ -575,9 +575,6 @@ Type::are_compatible_for_comparison(bool is_equality_op, const Type *t1,
 	       p != fields->end();
 	       ++p)
 	    {
-	      if (Gogo::is_sink_name(p->field_name()))
-		continue;
-
 	      if (!p->type()->is_comparable())
 		{
 		  if (reason != NULL)

gcc/testsuite/go.test/test/cmp.go

@@ -43,8 +43,8 @@ func main() {
 	var d string = "hel" // try to get different pointer
 	d = d + "lo"
 
-	// exp/ssa/interp can't handle unsafe.Pointer.
-	if os.Getenv("GOSSAINTERP") != "" {
+	// go.tools/ssa/interp can't handle unsafe.Pointer.
+	if os.Getenv("GOSSAINTERP") == "" {
 		if stringptr(c) == stringptr(d) {
 			panic("compiler too smart -- got same string")
 		}
@@ -296,7 +296,7 @@ func main() {
 	{
 		var x = struct {
 			x int
-			_ []int
+			_ string
 			y float64
 			_ float64
 			z int

gcc/testsuite/go.test/test/cmp6.go

@@ -53,7 +53,7 @@ func main() {
 
 	// Comparison of structs should have a good message
 	use(t3 == t3) // ERROR "struct|expected"
-	use(t4 == t4) // ok; the []int is a blank field
+	use(t4 == t4) // ERROR "cannot be compared|non-comparable"
 
 	// Slices, functions, and maps too.
 	var x []int