Fix a couple of bugs in linear_congruential_engine::seed. Regression test added.

llvm-svn: 182421

2 files changed, 11 insertions, 3 deletions

diff --git a/libcxx/include/random b/libcxx/include/random
index 92722ea64e7..f1076f97302 100644
--- a/libcxx/include/random
+++ b/libcxx/include/random
@@ -1835,7 +1835,7 @@ public:
     // types
     typedef _UIntType result_type;
 
-private:
+//private:
     result_type __x_;
 
     static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
@@ -1880,7 +1880,7 @@ public:
         seed(_Sseq& __q)
             {__seed(__q, integral_constant<unsigned,
                 1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
-                             :  (__m-1) / 0x100000000ull)>());}
+                             :  (__m > 0x100000000ull))>());}
 
     // generating functions
     _LIBCPP_INLINE_VISIBILITY
@@ -1969,7 +1969,7 @@ linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
     uint32_t __ar[__k+3];
     __q.generate(__ar, __ar + __k + 3);
     result_type __s = static_cast<result_type>((__ar[3] +
-                                                (uint64_t)__ar[4] << 32) % __m);
+                                              ((uint64_t)__ar[4] << 32)) % __m);
     __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
 }
 
diff --git a/libcxx/test/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp b/libcxx/test/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
index 470726f7f31..ca2793c7f9a 100644
--- a/libcxx/test/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
+++ b/libcxx/test/numerics/rand/rand.eng/rand.eng.lcong/seed_sseq.pass.cpp
@@ -28,4 +28,12 @@ int main()
         e1.seed(sseq);
         assert(e1 == e2);
     }
+    {
+        unsigned a[] = {3, 5, 7, 9, 11};
+        std::seed_seq sseq(a, a+5);
+        typedef std::linear_congruential_engine<unsigned long long, 1, 1, 0x200000001ULL> E;
+        E e1(4309005589);
+        E e2(sseq);
+        assert(e1 == e2);
+    }
 }