diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index cddff99466d..21ee3fd70f0 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,10 @@
+2016-09-16  Jonathan Wakely  <jwakely@redhat.com>
+	    Marc Glisse  <marc.glisse@inria.fr>
+
+	* libsupc++/new_opa.cc [_GLIBCXX_HAVE_ALIGNED_ALLOC]
+	(operator new(size_t, align_val_t)): Replace modulus operator with
+	mask.
+
 2016-09-16  Jonathan Wakely  <jwakely@redhat.com>
 
 	* libsupc++/new_opa.cc [_GLIBCXX_HAVE_POSIX_MEMALIGN] (aligned_alloc):
diff --git a/libstdc++-v3/libsupc++/new_opa.cc b/libstdc++-v3/libsupc++/new_opa.cc
index 9c859c1b61b..91e53a8b360 100644
--- a/libstdc++-v3/libsupc++/new_opa.cc
+++ b/libstdc++-v3/libsupc++/new_opa.cc
@@ -69,7 +69,7 @@ operator new (std::size_t sz, std::align_val_t al)
 
 #if _GLIBCXX_HAVE_ALIGNED_ALLOC
   /* C11: the value of size shall be an integral multiple of alignment.  */
-  if (std::size_t rem = sz % align)
+  if (std::size_t rem = sz & (align - 1))
     sz += align - rem;
 #endif