From: Jonathan Wakely <jwakely@redhat.com>
Date: Thu, 1 May 2025 21:41:40 +0000 (+0100)
Subject: libstdc++: Make __gnu_test::default_init_allocator usable in constexpr
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=869accb241c84f132ac0c9cd4e5ad9b4b7e6d536;p=thirdparty%2Fgcc.git

libstdc++: Make __gnu_test::default_init_allocator usable in constexpr

If we make this test allocator usable in constant expressions then we'll
get an error if the 'state' data member isn't initialized. This makes it
a more reliable check that allocators are correctly value-initialized
when they're required to be.

libstdc++-v3/ChangeLog:

	* testsuite/23_containers/vector/allocator/default_init.cc:
	Add a check using constant evaluation.
	* testsuite/23_containers/vector/bool/allocator/default_init.cc:
	Likewise.
	* testsuite/util/testsuite_allocator.h (default_init_allocator):
	Make all member functions and equality ops constexpr.
---

diff --git a/libstdc++-v3/testsuite/23_containers/vector/allocator/default_init.cc b/libstdc++-v3/testsuite/23_containers/vector/allocator/default_init.cc
index 195cd2dca544..486c44c9699d 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/allocator/default_init.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/allocator/default_init.cc
@@ -59,6 +59,17 @@ void test02()
   tmp->~test_type();
 }
 
+#ifdef __cpp_lib_constexpr_vector
+constexpr bool
+test03()
+{
+  using alloc_type = default_init_allocator<T>;
+  std::vector<T, alloc_type> v;
+  return v.get_allocator().state == 0;
+}
+static_assert( test03() );
+#endif
+
 int main()
 {
   test01();
diff --git a/libstdc++-v3/testsuite/23_containers/vector/bool/allocator/default_init.cc b/libstdc++-v3/testsuite/23_containers/vector/bool/allocator/default_init.cc
index 3914b7fe6c3a..c95cb6ba99f3 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/bool/allocator/default_init.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/bool/allocator/default_init.cc
@@ -59,6 +59,17 @@ void test02()
   tmp->~test_type();
 }
 
+#ifdef __cpp_lib_constexpr_vector
+constexpr bool
+test03()
+{
+  using alloc_type = default_init_allocator<T>;
+  std::vector<T, alloc_type> v;
+  return v.get_allocator().state == 0;
+}
+static_assert( test03() );
+#endif
+
 int main()
 {
   test01();
diff --git a/libstdc++-v3/testsuite/util/testsuite_allocator.h b/libstdc++-v3/testsuite/util/testsuite_allocator.h
index be596bf00fb4..e5ffad2ba587 100644
--- a/libstdc++-v3/testsuite/util/testsuite_allocator.h
+++ b/libstdc++-v3/testsuite/util/testsuite_allocator.h
@@ -541,15 +541,16 @@ namespace __gnu_test
       default_init_allocator() = default;
 
       template<typename U>
+	constexpr
         default_init_allocator(const default_init_allocator<U>& a)
 	  : state(a.state)
         { }
 
-      T*
+      constexpr T*
       allocate(std::size_t n)
       { return std::allocator<T>().allocate(n); }
 
-      void
+      constexpr void
       deallocate(T* p, std::size_t n)
       { std::allocator<T>().deallocate(p, n); }
 
@@ -557,15 +558,17 @@ namespace __gnu_test
     };
 
   template<typename T, typename U>
-    bool operator==(const default_init_allocator<T>& t,
-		    const default_init_allocator<U>& u)
+    constexpr bool
+    operator==(const default_init_allocator<T>& t,
+	       const default_init_allocator<U>& u)
     { return t.state == u.state; }
 
   template<typename T, typename U>
-    bool operator!=(const default_init_allocator<T>& t,
-		    const default_init_allocator<U>& u)
+    constexpr bool
+    operator!=(const default_init_allocator<T>& t,
+	       const default_init_allocator<U>& u)
     { return !(t == u); }
-#endif
+#endif // C++11
 
   template<typename Tp>
     struct ExplicitConsAlloc : std::allocator<Tp>