Remove some more code duplication in std::optional

Hoist the duplicated code from the _Optional_payload partial
specializations into the _Optional_payload_base base class.

	* include/std/optional (_Optional_payload_base::_M_copy_assign): New
	member function to perform non-trivial assignment.
	(_Optional_payload_base::_M_move_assign): Likewise.
	(_Optional_payload<T, true, false, true>::operator=)
	(_Optional_payload<T, true, true, false>::operator=)
	(_Optional_payload<T, true, false, false>::operator=): Call
	_M_copy_assign and/or _M_move_assign to do non-trivial assignments.

From-SVN: r267761

2 files changed, 45 insertions, 37 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 870fce2..d0f060d 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,13 @@
 2019-01-09  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/optional (_Optional_payload_base::_M_copy_assign): New
+	member function to perform non-trivial assignment.
+	(_Optional_payload_base::_M_move_assign): Likewise.
+	(_Optional_payload<T, true, false, true>::operator=)
+	(_Optional_payload<T, true, true, false>::operator=)
+	(_Optional_payload<T, true, false, false>::operator=): Call
+	_M_copy_assign and/or _M_move_assign to do non-trivial assignments.
+
 	PR libstdc++/88204
 	* testsuite/26_numerics/complex/operators/more_constexpr.cc: Do not
 	test std::complex<long double> if long double format is IBM128.
diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional
index b06e30f..c5e66bd 100644
--- a/libstdc++-v3/include/std/optional
+++ b/libstdc++-v3/include/std/optional
@@ -157,6 +157,38 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Optional_payload_base&
       operator=(_Optional_payload_base&&) = default;
 
+      // used to perform non-trivial copy assignment.
+      constexpr void
+      _M_copy_assign(const _Optional_payload_base& __other)
+      {
+        if (this->_M_engaged && __other._M_engaged)
+          this->_M_get() = __other._M_get();
+        else
+	  {
+	    if (__other._M_engaged)
+	      this->_M_construct(__other._M_get());
+	    else
+	      this->_M_reset();
+	  }
+      }
+
+      // used to perform non-trivial move assignment.
+      constexpr void
+      _M_move_assign(_Optional_payload_base&& __other)
+      noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
+		       is_nothrow_move_assignable<_Tp>>)
+      {
+	if (this->_M_engaged && __other._M_engaged)
+	  this->_M_get() = std::move(__other._M_get());
+	else
+	  {
+	    if (__other._M_engaged)
+	      this->_M_construct(std::move(__other._M_get()));
+	    else
+	      this->_M_reset();
+	  }
+      }
+
       struct _Empty_byte { };
 
       template<typename _Up, bool = is_trivially_destructible_v<_Up>>
@@ -286,15 +318,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Optional_payload&
       operator=(const _Optional_payload& __other)
       {
-        if (this->_M_engaged && __other._M_engaged)
-          this->_M_get() = __other._M_get();
-        else
-	  {
-	    if (__other._M_engaged)
-	      this->_M_construct(__other._M_get());
-	    else
-	      this->_M_reset();
-	  }
+	this->_M_copy_assign(__other);
 	return *this;
       }
     };
@@ -319,15 +343,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
 		       is_nothrow_move_assignable<_Tp>>)
       {
-	if (this->_M_engaged && __other._M_engaged)
-	  this->_M_get() = std::move(__other._M_get());
-	else
-	  {
-	    if (__other._M_engaged)
-	      this->_M_construct(std::move(__other._M_get()));
-	    else
-	      this->_M_reset();
-	  }
+	this->_M_move_assign(std::move(__other));
 	return *this;
       }
     };
@@ -344,20 +360,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       _Optional_payload(const _Optional_payload&) = default;
       _Optional_payload(_Optional_payload&&) = default;
 
-      // Non-trivial copy
+      // Non-trivial copy assignment.
       constexpr
       _Optional_payload&
       operator=(const _Optional_payload& __other)
       {
-        if (this->_M_engaged && __other._M_engaged)
-          this->_M_get() = __other._M_get();
-        else
-	  {
-	    if (__other._M_engaged)
-	      this->_M_construct(__other._M_get());
-	    else
-	      this->_M_reset();
-	  }
+	this->_M_copy_assign(__other);
 	return *this;
       }
 
@@ -368,15 +376,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
 		       is_nothrow_move_assignable<_Tp>>)
       {
-	if (this->_M_engaged && __other._M_engaged)
-	  this->_M_get() = std::move(__other._M_get());
-	else
-	  {
-	    if (__other._M_engaged)
-	      this->_M_construct(std::move(__other._M_get()));
-	    else
-	      this->_M_reset();
-	  }
+	this->_M_move_assign(std::move(__other));
 	return *this;
       }
     };