Applied constexpr to <chrono>.

llvm-svn: 160184
diff --git a/libcxx/test/utilities/time/rep.h b/libcxx/test/utilities/time/rep.h
index ea4db2d..59c58bb 100644
--- a/libcxx/test/utilities/time/rep.h
+++ b/libcxx/test/utilities/time/rep.h
@@ -5,11 +5,11 @@
 {
     int data_;
 public:
-    Rep() : data_(-1) {}
-    explicit Rep(int i) : data_(i) {}
+    _LIBCPP_CONSTEXPR Rep() : data_(-1) {}
+    explicit _LIBCPP_CONSTEXPR Rep(int i) : data_(i) {}
 
-    bool operator==(int i) const {return data_ == i;}
-    bool operator==(const Rep& r) const {return data_ == r.data_;}
+    bool _LIBCPP_CONSTEXPR operator==(int i) const {return data_ == i;}
+    bool _LIBCPP_CONSTEXPR operator==(const Rep& r) const {return data_ == r.data_;}
 
     Rep& operator*=(Rep x) {data_ *= x.data_; return *this;}
     Rep& operator/=(Rep x) {data_ /= x.data_; return *this;}
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
index 3103b23..c0f1014 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
@@ -18,7 +18,16 @@
 
 int main()
 {
+    {
     const std::chrono::minutes m(3);
     std::chrono::minutes m2 = +m;
     assert(m.count() == m2.count());
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::minutes m(3);
+    constexpr std::chrono::minutes m2 = +m;
+    static_assert(m.count() == m2.count(), "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
index aa7f748..00da6f6 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
@@ -18,7 +18,16 @@
 
 int main()
 {
+    {
     const std::chrono::minutes m(3);
     std::chrono::minutes m2 = -m;
     assert(m2.count() == -m.count());
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::minutes m(3);
+    constexpr std::chrono::minutes m2 = -m;
+    static_assert(m2.count() == -m.count(), "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
index 053ab99..1c87fcd 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class ToDuration, class Rep, class Period>
+//   constexpr
 //   ToDuration
 //   duration_cast(const duration<Rep, Period>& d);
 
@@ -23,9 +24,11 @@
 void
 test(const FromDuration& f, const ToDuration& d)
 {
+    {
     typedef decltype(std::chrono::duration_cast<ToDuration>(f)) R;
     static_assert((std::is_same<R, ToDuration>::value), "");
     assert(std::chrono::duration_cast<ToDuration>(f) == d);
+    }
 }
 
 int main()
@@ -40,4 +43,10 @@
          std::chrono::duration<double, std::ratio<3600> >(7265./3600));
     test(std::chrono::duration<int, std::ratio<2, 3> >(9),
          std::chrono::duration<int, std::ratio<3, 5> >(10));
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::hours h = std::chrono::duration_cast<std::chrono::hours>(std::chrono::milliseconds(7265000));
+    static_assert(h.count() == 2, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
index 154d43d..2d0dd94 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
@@ -12,10 +12,12 @@
 // duration
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator==(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator!=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
@@ -66,4 +68,48 @@
     assert(s1 == s2);
     assert(!(s1 != s2));
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(3);
+    static_assert(s1 == s2, "");
+    static_assert(!(s1 != s2), "");
+    }
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(4);
+    static_assert(!(s1 == s2), "");
+    static_assert(s1 != s2, "");
+    }
+    {
+    constexpr std::chrono::milliseconds s1(3);
+    constexpr std::chrono::microseconds s2(3000);
+    static_assert(s1 == s2, "");
+    static_assert(!(s1 != s2), "");
+    }
+    {
+    constexpr std::chrono::milliseconds s1(3);
+    constexpr std::chrono::microseconds s2(4000);
+    static_assert(!(s1 == s2), "");
+    static_assert(s1 != s2, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(9);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(10);
+    static_assert(s1 == s2, "");
+    static_assert(!(s1 != s2), "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(10);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(9);
+    static_assert(!(s1 == s2), "");
+    static_assert(s1 != s2, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(9);
+    constexpr std::chrono::duration<double, std::ratio<3, 5> > s2(10);
+    static_assert(s1 == s2, "");
+    static_assert(!(s1 != s2), "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
index daf7e89..9d87557 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
@@ -12,18 +12,22 @@
 // duration
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator< (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator> (const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator<=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   bool
 //   operator>=(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
@@ -88,4 +92,62 @@
     assert( (s1 <= s2));
     assert( (s1 >= s2));
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(3);
+    static_assert(!(s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert( (s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(4);
+    static_assert( (s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert(!(s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::milliseconds s1(3);
+    constexpr std::chrono::microseconds s2(3000);
+    static_assert(!(s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert( (s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::milliseconds s1(3);
+    constexpr std::chrono::microseconds s2(4000);
+    static_assert( (s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert(!(s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(9);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(10);
+    static_assert(!(s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert( (s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(10);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(9);
+    static_assert(!(s1 < s2), "");
+    static_assert( (s1 > s2), "");
+    static_assert(!(s1 <= s2), "");
+    static_assert( (s1 >= s2), "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(9);
+    constexpr std::chrono::duration<double, std::ratio<3, 5> > s2(10);
+    static_assert(!(s1 < s2), "");
+    static_assert(!(s1 > s2), "");
+    static_assert( (s1 <= s2), "");
+    static_assert( (s1 >= s2), "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
index e7380f7..152227d 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
@@ -21,7 +21,16 @@
 
 int main()
 {
+    {
     std::chrono::milliseconds ms(1);
     std::chrono::microseconds us = ms;
     assert(us.count() == 1000);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::milliseconds ms(1);
+    constexpr std::chrono::microseconds us = ms;
+    static_assert(us.count() == 1000, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
index 0eba13a..519b2b1 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
@@ -21,7 +21,16 @@
 
 int main()
 {
+    {
     std::chrono::duration<double, std::micro> us(1);
     std::chrono::duration<double, std::milli> ms = us;
     assert(ms.count() == 1./1000);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::duration<double, std::micro> us(1);
+    constexpr std::chrono::duration<double, std::milli> ms = us;
+    static_assert(ms.count() == 1./1000, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
index 1095cf3..59fefe2 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
@@ -21,7 +21,16 @@
 
 int main()
 {
+    {
     std::chrono::duration<int> i(3);
-    std::chrono::duration<int> d = i;
-    assert(d.count() == 3);
+    std::chrono::duration<double, std::milli> d = i;
+    assert(d.count() == 3000);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::duration<int> i(3);
+    constexpr std::chrono::duration<double, std::milli> d = i;
+    static_assert(d.count() == 3000, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/default.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/default.pass.cpp
index 6e048b2..837f437 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/default.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/default.pass.cpp
@@ -26,6 +26,10 @@
 {
     D d;
     assert(d.count() == typename D::rep());
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    constexpr D d2;
+    static_assert(d2.count() == typename D::rep(), "");
+#endif
 }
 
 int main()
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/rep.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
index 9879568..20f8161 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
@@ -25,6 +25,10 @@
 {
     D d(r);
     assert(d.count() == r);
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    constexpr D d2(R(2));
+    static_assert(d2.count() == 2, "");
+#endif
 }
 
 int main()
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
index c34a4ff..b3ba9f7 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
@@ -23,4 +23,8 @@
 {
     std::chrono::duration<double> d(5);
     assert(d.count() == 5);
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    constexpr std::chrono::duration<double> d2(5);
+    static_assert(d2.count() == 5, "");
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
index d2c194e..6585351 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
@@ -44,4 +44,30 @@
     std::chrono::duration<double, std::ratio<1, 15> > r = s1 + s2;
     assert(r.count() == 75);
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(5);
+    constexpr std::chrono::seconds r = s1 + s2;
+    static_assert(r.count() == 8, "");
+    }
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::microseconds s2(5);
+    constexpr std::chrono::microseconds r = s1 + s2;
+    static_assert(r.count() == 3000005, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(3);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(5);
+    constexpr std::chrono::duration<int, std::ratio<1, 15> > r = s1 + s2;
+    static_assert(r.count() == 75, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(3);
+    constexpr std::chrono::duration<double, std::ratio<3, 5> > s2(5);
+    constexpr std::chrono::duration<double, std::ratio<1, 15> > r = s1 + s2;
+    static_assert(r.count() == 75, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
index 4418543..fac58b9 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
 //   operator-(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
@@ -44,4 +45,30 @@
     std::chrono::duration<double, std::ratio<1, 15> > r = s1 - s2;
     assert(r.count() == -15);
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::seconds s2(5);
+    constexpr std::chrono::seconds r = s1 - s2;
+    static_assert(r.count() == -2, "");
+    }
+    {
+    constexpr std::chrono::seconds s1(3);
+    constexpr std::chrono::microseconds s2(5);
+    constexpr std::chrono::microseconds r = s1 - s2;
+    static_assert(r.count() == 2999995, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(3);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(5);
+    constexpr std::chrono::duration<int, std::ratio<1, 15> > r = s1 - s2;
+    static_assert(r.count() == -15, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(3);
+    constexpr std::chrono::duration<double, std::ratio<3, 5> > s2(5);
+    constexpr std::chrono::duration<double, std::ratio<1, 15> > r = s1 - s2;
+    static_assert(r.count() == -15, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
index d413404..6b24676 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   typename common_type<Rep1, Rep2>::type
 //   operator/(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
@@ -40,4 +41,26 @@
     std::chrono::duration<double, std::ratio<3, 5> > s2(5);
     assert(s1 / s2 == 20./3);
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::nanoseconds ns1(15);
+    constexpr std::chrono::nanoseconds ns2(5);
+    static_assert(ns1 / ns2 == 3, "");
+    }
+    {
+    constexpr std::chrono::microseconds us1(15);
+    constexpr std::chrono::nanoseconds ns2(5);
+    static_assert(us1 / ns2 == 3000, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(30);
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s2(5);
+    static_assert(s1 / s2 == 6, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s1(30);
+    constexpr std::chrono::duration<double, std::ratio<3, 5> > s2(5);
+    static_assert(s1 / s2 == 20./3, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
index 2245e92..3036cde 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class Rep1, class Period, class Rep2>
+//   constexpr
 //   duration<typename common_type<Rep1, Rep2>::type, Period>
 //   operator/(const duration<Rep1, Period>& d, const Rep2& s);
 
@@ -20,7 +21,16 @@
 
 int main()
 {
+    {
     std::chrono::nanoseconds ns(15);
     ns = ns / 5;
     assert(ns.count() == 3);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::nanoseconds ns(15);
+    constexpr std::chrono::nanoseconds ns2 = ns / 5;
+    static_assert(ns2.count() == 3, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
index 99f8c59..e69f320 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class Rep1, class Period1, class Rep2, class Period2>
+//   constexpr
 //   typename common_type<duration<Rep1, Period1>, duration<Rep2, Period2>>::type
 //   operator%(const duration<Rep1, Period1>& lhs, const duration<Rep2, Period2>& rhs);
 
@@ -38,4 +39,24 @@
     std::chrono::duration<int, std::ratio<1, 15> > r = s1 % s2;
     assert(r.count() == 24);
     }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::nanoseconds ns1(15);
+    constexpr std::chrono::nanoseconds ns2(6);
+    constexpr std::chrono::nanoseconds r = ns1 % ns2;
+    static_assert(r.count() == 3, "");
+    }
+    {
+    constexpr std::chrono::microseconds us1(15);
+    constexpr std::chrono::nanoseconds ns2(28);
+    constexpr std::chrono::nanoseconds r = us1 % ns2;
+    static_assert(r.count() == 20, "");
+    }
+    {
+    constexpr std::chrono::duration<int, std::ratio<3, 5> > s1(6);
+    constexpr std::chrono::duration<int, std::ratio<2, 3> > s2(3);
+    constexpr std::chrono::duration<int, std::ratio<1, 15> > r = s1 % s2;
+    static_assert(r.count() == 24, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
index 4b379a0..1acbe34 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
@@ -12,6 +12,7 @@
 // duration
 
 // template <class Rep1, class Period, class Rep2>
+//   constexpr
 //   duration<typename common_type<Rep1, Rep2>::type, Period>
 //   operator%(const duration<Rep1, Period>& d, const Rep2& s)
 
@@ -20,7 +21,16 @@
 
 int main()
 {
+    {
     std::chrono::nanoseconds ns(15);
     ns = ns % 6;
     assert(ns.count() == 3);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::nanoseconds ns(15);
+    constexpr std::chrono::nanoseconds ns2 = ns % 6;
+    static_assert(ns2.count() == 3, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
index ecfe7a9..190e74b 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
@@ -12,10 +12,12 @@
 // duration
 
 // template <class Rep1, class Period, class Rep2>
+//   constexpr
 //   duration<typename common_type<Rep1, Rep2>::type, Period>
 //   operator*(const duration<Rep1, Period>& d, const Rep2& s);
 
 // template <class Rep1, class Period, class Rep2>
+//   constexpr
 //   duration<typename common_type<Rep1, Rep2>::type, Period>
 //   operator*(const Rep1& s, const duration<Rep2, Period>& d);
 
@@ -24,9 +26,20 @@
 
 int main()
 {
+    {
     std::chrono::nanoseconds ns(3);
     ns = ns * 5;
     assert(ns.count() == 15);
     ns = 6 * ns;
     assert(ns.count() == 90);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    constexpr std::chrono::nanoseconds ns(3);
+    constexpr std::chrono::nanoseconds ns2 = ns * 5;
+    static_assert(ns2.count() == 15, "");
+    constexpr std::chrono::nanoseconds ns3 = 6 * ns;
+    static_assert(ns3.count() == 18, "");
+    }
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.special/max.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.special/max.pass.cpp
index a9e60d7..405461e 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.special/max.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.special/max.pass.cpp
@@ -22,9 +22,18 @@
 template <class D>
 void test()
 {
+    {
     typedef typename D::rep Rep;
     Rep max_rep = std::chrono::duration_values<Rep>::max();
     assert(D::max().count() == max_rep);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    typedef typename D::rep Rep;
+    constexpr Rep max_rep = std::chrono::duration_values<Rep>::max();
+    static_assert(D::max().count() == max_rep, "");
+    }
+#endif
 }
 
 int main()
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.special/min.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.special/min.pass.cpp
index e32fe0b..44cd64e 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.special/min.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.special/min.pass.cpp
@@ -22,9 +22,18 @@
 template <class D>
 void test()
 {
+    {
     typedef typename D::rep Rep;
     Rep min_rep = std::chrono::duration_values<Rep>::min();
     assert(D::min().count() == min_rep);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    typedef typename D::rep Rep;
+    constexpr Rep min_rep = std::chrono::duration_values<Rep>::min();
+    static_assert(D::min().count() == min_rep, "");
+    }
+#endif
 }
 
 int main()
diff --git a/libcxx/test/utilities/time/time.duration/time.duration.special/zero.pass.cpp b/libcxx/test/utilities/time/time.duration/time.duration.special/zero.pass.cpp
index c919ad8..18350fe 100644
--- a/libcxx/test/utilities/time/time.duration/time.duration.special/zero.pass.cpp
+++ b/libcxx/test/utilities/time/time.duration/time.duration.special/zero.pass.cpp
@@ -21,9 +21,18 @@
 template <class D>
 void test()
 {
+    {
     typedef typename D::rep Rep;
     Rep zero_rep = std::chrono::duration_values<Rep>::zero();
     assert(D::zero().count() == zero_rep);
+    }
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    {
+    typedef typename D::rep Rep;
+    constexpr Rep zero_rep = std::chrono::duration_values<Rep>::zero();
+    static_assert(D::zero().count() == zero_rep, "");
+    }
+#endif
 }
 
 int main()
diff --git a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
index 2408416..89dc1dc 100644
--- a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
+++ b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
@@ -25,4 +25,12 @@
            std::numeric_limits<double>::max());
     assert(std::chrono::duration_values<Rep>::max() ==
            std::numeric_limits<Rep>::max());
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    static_assert(std::chrono::duration_values<int>::max() ==
+           std::numeric_limits<int>::max(), "");
+    static_assert(std::chrono::duration_values<double>::max() ==
+           std::numeric_limits<double>::max(), "");
+    static_assert(std::chrono::duration_values<Rep>::max() ==
+           std::numeric_limits<Rep>::max(), "");
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
index 420cbb4..69812bb 100644
--- a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
+++ b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
@@ -25,4 +25,12 @@
            std::numeric_limits<double>::lowest());
     assert(std::chrono::duration_values<Rep>::min() ==
            std::numeric_limits<Rep>::lowest());
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    static_assert(std::chrono::duration_values<int>::min() ==
+           std::numeric_limits<int>::lowest(), "");
+    static_assert(std::chrono::duration_values<double>::min() ==
+           std::numeric_limits<double>::lowest(), "");
+    static_assert(std::chrono::duration_values<Rep>::min() ==
+           std::numeric_limits<Rep>::lowest(), "");
+#endif
 }
diff --git a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
index 2a6e90f..234b4bc 100644
--- a/libcxx/test/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
+++ b/libcxx/test/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
@@ -20,4 +20,8 @@
 {
     assert(std::chrono::duration_values<int>::zero() == 0);
     assert(std::chrono::duration_values<Rep>::zero() == 0);
+#ifndef _LIBCPP_HAS_NO_CONSTEXPR
+    static_assert(std::chrono::duration_values<int>::zero() == 0, "");
+    static_assert(std::chrono::duration_values<Rep>::zero() == 0, "");
+#endif
 }