libstdc++: Simplify std::optional::value()

The structure of these functions likely dates from the time before G++
fully supported C++14 extended constexpr, so that the throw expression
had to be the operand of a conditional expression. That is not true now,
so we can use a more straightforward version of the code.

We can also simplify the declaration of __throw_bad_optional_access by
using the C++11-style [[noreturn]] attribute so that a separate
declaration isn't needed.

libstdc++-v3/ChangeLog:

	* include/experimental/optional (__throw_bad_optional_access):
	Replace GNU attribute with C++11 attribute.
	(optional::value, optional::value_or): Use if statements
	instead of conditional expressions.
	* include/std/optional (__throw_bad_optional_access)
	(optional::value, optional::value_or): Likewise.

diff --git a/libstdc++-v3/include/experimental/optional b/libstdc++-v3/include/experimental/optional
index 431d23631cf16a35886f31cbe1335ecac44fb295..274c974853ddec13dc272673f08595882fb64eb8 100644 (file)
--- a/libstdc++-v3/include/experimental/optional
+++ b/libstdc++-v3/include/experimental/optional
@@ -114,12 +114,8 @@ inline namespace fundamentals_v1
 
   /// @cond undocumented
 
-  void
-  __throw_bad_optional_access(const char*)
-  __attribute__((__noreturn__));
-
   // XXX Does not belong here.
-  inline void
+  [[noreturn]] inline void
   __throw_bad_optional_access(const char* __s)
   { _GLIBCXX_THROW_OR_ABORT(bad_optional_access(__s)); }
 
@@ -674,41 +670,37 @@ inline namespace fundamentals_v1
       constexpr const _Tp&
       value() const&
       {
-       return this->_M_is_engaged()
-         ?  this->_M_get()
-         : (__throw_bad_optional_access("Attempt to access value of a "
-                                        "disengaged optional object"),
-            this->_M_get());
+       if (this->_M_is_engaged())
+         return this->_M_get();
+       __throw_bad_optional_access("Attempt to access value of a "
+                                   "disengaged optional object");
       }
 
       constexpr _Tp&
       value()&
       {
-       return this->_M_is_engaged()
-         ?  this->_M_get()
-         : (__throw_bad_optional_access("Attempt to access value of a "
-                                        "disengaged optional object"),
-            this->_M_get());
+       if (this->_M_is_engaged())
+         return this->_M_get();
+       __throw_bad_optional_access("Attempt to access value of a "
+                                   "disengaged optional object");
       }
 
       constexpr _Tp&&
       value()&&
       {
-       return this->_M_is_engaged()
-         ?  std::move(this->_M_get())
-         : (__throw_bad_optional_access("Attempt to access value of a "
-                                        "disengaged optional object"),
-            std::move(this->_M_get()));
+       if (this->_M_is_engaged())
+         return std::move(this->_M_get());
+       __throw_bad_optional_access("Attempt to access value of a "
+                                   "disengaged optional object");
       }
 
       constexpr const _Tp&&
       value() const&&
       {
-       return this->_M_is_engaged()
-         ?  std::move(this->_M_get())
-         : (__throw_bad_optional_access("Attempt to access value of a "
-                                        "disengaged optional object"),
-            std::move(this->_M_get()));
+       if (this->_M_is_engaged())
+         return std::move(this->_M_get());
+       __throw_bad_optional_access("Attempt to access value of a "
+                                   "disengaged optional object");
       }
 
       template<typename _Up>
@@ -719,9 +711,10 @@ inline namespace fundamentals_v1
                               is_convertible<_Up&&, _Tp>>(),
                        "Cannot return value");
 
-         return this->_M_is_engaged()
-           ? this->_M_get()
-           : static_cast<_Tp>(std::forward<_Up>(__u));
+         if (this->_M_is_engaged())
+           return this->_M_get();
+         else
+           return static_cast<_Tp>(std::forward<_Up>(__u));
        }
 
       template<typename _Up>
@@ -732,9 +725,10 @@ inline namespace fundamentals_v1
                               is_convertible<_Up&&, _Tp>>(),
                        "Cannot return value" );
 
-         return this->_M_is_engaged()
-           ? std::move(this->_M_get())
-           : static_cast<_Tp>(std::forward<_Up>(__u));
+         if (this->_M_is_engaged())
+           return std::move(this->_M_get());
+         else
+           return static_cast<_Tp>(std::forward<_Up>(__u));
        }
     };
 

diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional
index df9ed0736b391d785486611c6d403f25193c3cf1..b8ab75107572d7fe56ce649fe4f6e9506e3b5cd5 100644 (file)
--- a/libstdc++-v3/include/std/optional
+++ b/libstdc++-v3/include/std/optional
@@ -91,12 +91,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     { return "bad optional access"; }
   };
 
-  void
-  __throw_bad_optional_access()
-  __attribute__((__noreturn__));
-
   // XXX Does not belong here.
-  inline void
+  [[__noreturn__]] inline void
   __throw_bad_optional_access()
   { _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
 
@@ -943,33 +939,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr const _Tp&
       value() const&
       {
-       return this->_M_is_engaged()
-         ? this->_M_get()
-         : (__throw_bad_optional_access(), this->_M_get());
+       if (this->_M_is_engaged())
+         return this->_M_get();
+       __throw_bad_optional_access();
       }
 
       constexpr _Tp&
       value()&
       {
-       return this->_M_is_engaged()
-         ? this->_M_get()
-         : (__throw_bad_optional_access(), this->_M_get());
+       if (this->_M_is_engaged())
+         return this->_M_get();
+       __throw_bad_optional_access();
       }
 
       constexpr _Tp&&
       value()&&
       {
-       return this->_M_is_engaged()
-         ? std::move(this->_M_get())
-         : (__throw_bad_optional_access(), std::move(this->_M_get()));
+       if (this->_M_is_engaged())
+         return std::move(this->_M_get());
+       __throw_bad_optional_access();
       }
 
       constexpr const _Tp&&
       value() const&&
       {
-       return this->_M_is_engaged()
-         ? std::move(this->_M_get())
-         : (__throw_bad_optional_access(), std::move(this->_M_get()));
+       if (this->_M_is_engaged())
+         return std::move(this->_M_get());
+       __throw_bad_optional_access();
       }
 
       template<typename _Up>
@@ -979,8 +975,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          static_assert(is_copy_constructible_v<_Tp>);
          static_assert(is_convertible_v<_Up&&, _Tp>);
 
-         return this->_M_is_engaged()
-           ? this->_M_get() : static_cast<_Tp>(std::forward<_Up>(__u));
+         if (this->_M_is_engaged())
+           return this->_M_get();
+         else
+           return static_cast<_Tp>(std::forward<_Up>(__u));
        }
 
       template<typename _Up>
@@ -990,9 +988,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          static_assert(is_move_constructible_v<_Tp>);
          static_assert(is_convertible_v<_Up&&, _Tp>);
 
-         return this->_M_is_engaged()
-           ? std::move(this->_M_get())
-           : static_cast<_Tp>(std::forward<_Up>(__u));
+         if (this->_M_is_engaged())
+           return std::move(this->_M_get());
+         else
+           return static_cast<_Tp>(std::forward<_Up>(__u));
        }
 
       void reset() noexcept { this->_M_reset(); }