Fix multiple_p for two non-poly_ints

Fix a stupid inversion.  This function is very rarely used and was
mostly to help split patches up, which is why it didn't get picked
up during initial testing.

2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* poly-int.h (multiple_p): Fix handling of two non-poly_ints.

gcc/testsuite/
	* gcc.dg/plugin/poly-int-tests.h (test_nonpoly_multiple_p): New
	function.
	(test_nonpoly_type): Call it.

From-SVN: r255860

gcc/ChangeLog

+2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* poly-int.h (multiple_p): Fix handling of two non-poly_ints.
+
 2017-12-20  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* doc/invoke.texi (ARM Options): Document accepted extension options

gcc/poly-int.h

@@ -2027,7 +2027,7 @@ template<typename Ca, typename Cb>
 inline typename if_nonpoly2<Ca, Cb, bool>::type
 multiple_p (Ca a, Cb b)
 {
-  return a % b != 0;
+  return a % b == 0;
 }
 
 /* Return true if A is a (polynomial) multiple of B.  */

gcc/testsuite/ChangeLog

+2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>
+
+	* gcc.dg/plugin/poly-int-tests.h (test_nonpoly_multiple_p): New
+	function.
+	(test_nonpoly_type): Call it.
+
 2017-12-20  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/83490

gcc/testsuite/gcc.dg/plugin/poly-int-tests.h

@@ -4505,6 +4505,19 @@ test_uhwi ()
 				   wi::uhwi (210, 16)));
 }
 
+/* Test multiple_p for non-polynomial T.  */
+
+template<typename T>
+static void
+test_nonpoly_multiple_p ()
+{
+  ASSERT_TRUE (multiple_p (T (6), T (2)));
+  ASSERT_TRUE (multiple_p (T (6), T (3)));
+  ASSERT_FALSE (multiple_p (T (6), T (4)));
+  ASSERT_FALSE (multiple_p (T (7), T (4)));
+  ASSERT_TRUE (multiple_p (T (8), T (4)));
+}
+
 /* Test known_size_p for non-polynomial T.  */
 
 template<typename T>
@@ -4523,6 +4536,7 @@ template<typename T>
 static void
 test_nonpoly_type ()
 {
+  test_nonpoly_multiple_p<T> ();
   test_nonpoly_known_size_p<T> ();
 }