random.h (mersenne_twister_engine): Don't inline discard here.

	* include/bits/random.h (mersenne_twister_engine): Don't inline
	discard here.  New member function _M_gen_rand.
	* include/bits/random.tcc (mersenne_twister_engine<>::_M_gen_rand):
	New function.  Extracted from operator().
	(mersenne_twister_engine<>::discard): New implementation which
	skips in large steps.
	(mersenne_twister_engine<>::operator()): Use _M_gen_rand.

From-SVN: r190711

libstdc++-v3/ChangeLog

+012-08-22  Ulrich Drepper  <drepper@gmail.com>
+
+	* include/bits/random.h (mersenne_twister_engine): Don't inline
+	discard here.  New member function _M_gen_rand.
+	* include/bits/random.tcc (mersenne_twister_engine<>::_M_gen_rand):
+	New function.  Extracted from operator().
+	(mersenne_twister_engine<>::discard): New implementation which
+	skips in large steps.
+	(mersenne_twister_engine<>::operator()): Use _M_gen_rand.
+							
 2012-08-26  Marc Glisse  <marc.glisse@inria.fr>
 	    Paolo Carlini  <paolo.carlini@oracle.com>
 

libstdc++-v3/include/bits/random.h

@@ -530,11 +530,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        * @brief Discard a sequence of random numbers.
        */
       void
-      discard(unsigned long long __z)
-      {
-	for (; __z != 0ULL; --__z)
-	  (*this)();
-      }
+      discard(unsigned long long __z);
 
       result_type
       operator()();
@@ -610,6 +606,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		   __l1, __f1>& __x);
 
     private:
+      void _M_gen_rand();
+
       _UIntType _M_x[state_size];
       size_t    _M_p;
     };

libstdc++-v3/include/bits/random.tcc

@@ -392,15 +392,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
 	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
 	   _UIntType __f>
-    typename
-    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
-			    __s, __b, __t, __c, __l, __f>::result_type
+    void
     mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
 			    __s, __b, __t, __c, __l, __f>::
-    operator()()
-    {
-      // Reload the vector - cost is O(n) amortized over n calls.
-      if (_M_p >= state_size)
+    _M_gen_rand(void)
     {
       const _UIntType __upper_mask = (~_UIntType()) << __r;
       const _UIntType __lower_mask = ~__upper_mask;
@@ -428,6 +423,40 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _M_p = 0;
     }
 
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    void
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    discard(unsigned long long __z)
+    {
+      while (__z > state_size - _M_p)
+	{
+	  __z -= state_size - _M_p;
+	  _M_gen_rand();
+	}
+      _M_p += __z;
+    }
+
+  template<typename _UIntType, size_t __w,
+	   size_t __n, size_t __m, size_t __r,
+	   _UIntType __a, size_t __u, _UIntType __d, size_t __s,
+	   _UIntType __b, size_t __t, _UIntType __c, size_t __l,
+	   _UIntType __f>
+    typename
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::result_type
+    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d,
+			    __s, __b, __t, __c, __l, __f>::
+    operator()()
+    {
+      // Reload the vector - cost is O(n) amortized over n calls.
+      if (_M_p >= state_size)
+	_M_gen_rand();
+
       // Calculate o(x(i)).
       result_type __z = _M_x[_M_p++];
       __z ^= (__z >> __u) & __d;