[committed,v2] libstdc++: Deprecate useless <cxxx> compatibility headers for C++17

diff --git a/gcc/testsuite/g++.old-deja/g++.other/headers1.C b/gcc/testsuite/g++.old-deja/g++.other/headers1.C
index 5d37e94082f..90a1a7dc8f9 100644
--- a/gcc/testsuite/g++.old-deja/g++.other/headers1.C
+++ b/gcc/testsuite/g++.old-deja/g++.other/headers1.C
@@ -12,7 +12,9 @@ 
 #include <cctype>
 #include <cerrno>
 #include <cfloat>
+#if __cplusplus < 201703L
 #include <ciso646>
+#endif
 #include <climits>
 #include <clocale>
 #include <cmath>
diff --git a/libstdc++-v3/doc/html/manual/api.html b/libstdc++-v3/doc/html/manual/api.html
index 799f6eae2a2..2ccfc07b83e 100644
--- a/libstdc++-v3/doc/html/manual/api.html
+++ b/libstdc++-v3/doc/html/manual/api.html
@@ -498,4 +498,12 @@  to be used with <code class="code">std::basic_istream</code>.
   longer allowed in C++20 mode.
 </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="api.rel_151"></a><code class="constant">15</code></h3></div></div></div><p>
 Enabled debug assertions by default for unoptimized builds.
+</p><p>
+Added warnings when including the headers that were deprecated in C++17
+and removed in C++20:
+<code class="filename">&lt;ccomplex&gt;</code>,
+<code class="filename">&lt;ciso646&gt;</code>,
+<code class="filename">&lt;cstdalign&gt;</code>,
+<code class="filename">&lt;cstdbool&gt;</code>, and
+<code class="filename">&lt;ctgmath&gt;</code>.
 </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="abi.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="appendix_porting.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="backwards.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ABI Policy and Guidelines </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> Backwards Compatibility</td></tr></table></div></body></html>
\ No newline at end of file
diff --git a/libstdc++-v3/doc/xml/manual/evolution.xml b/libstdc++-v3/doc/xml/manual/evolution.xml
index 75cf948a4a2..6b134de0e71 100644
--- a/libstdc++-v3/doc/xml/manual/evolution.xml
+++ b/libstdc++-v3/doc/xml/manual/evolution.xml
@@ -1135,6 +1135,16 @@  to be used with <code>std::basic_istream</code>.
 Enabled debug assertions by default for unoptimized builds.
 </para>
 
+<para>
+Added warnings when including the headers that were deprecated in C++17
+and removed in C++20:
+<filename class="headerfile">&lt;ccomplex&gt;</filename>,
+<filename class="headerfile">&lt;ciso646&gt;</filename>,
+<filename class="headerfile">&lt;cstdalign&gt;</filename>,
+<filename class="headerfile">&lt;cstdbool&gt;</filename>, and
+<filename class="headerfile">&lt;ctgmath&gt;</filename>.
+</para>
+
 </section>
 
 </section>
diff --git a/libstdc++-v3/include/c_compatibility/complex.h b/libstdc++-v3/include/c_compatibility/complex.h
index a3102d9fce3..461ff2117b1 100644
--- a/libstdc++-v3/include/c_compatibility/complex.h
+++ b/libstdc++-v3/include/c_compatibility/complex.h
@@ -32,7 +32,9 @@ 
 #include <bits/c++config.h>
 
 #if __cplusplus >= 201103L
-# include <ccomplex>
+extern "C++" {
+#include <complex>
+}
 #endif
 
 #if __cplusplus >= 201103L && defined(__STRICT_ANSI__)
diff --git a/libstdc++-v3/include/c_compatibility/tgmath.h b/libstdc++-v3/include/c_compatibility/tgmath.h
index aadddd91b60..6bf6727a15c 100644
--- a/libstdc++-v3/include/c_compatibility/tgmath.h
+++ b/libstdc++-v3/include/c_compatibility/tgmath.h
@@ -32,11 +32,12 @@ 
 #include <bits/c++config.h>
 
 #if __cplusplus >= 201103L
-# include <ctgmath>
-#else
-# if _GLIBCXX_HAVE_TGMATH_H
-#  include_next <tgmath.h>
-# endif
+# include <cmath>
+extern "C++" {
+# include <complex>
+}
+#elif _GLIBCXX_HAVE_TGMATH_H
+# include_next <tgmath.h>
 #endif
 
 #endif
diff --git a/libstdc++-v3/include/c_global/ccomplex b/libstdc++-v3/include/c_global/ccomplex
index ee1166aaecb..5e47ddd68cc 100644
--- a/libstdc++-v3/include/c_global/ccomplex
+++ b/libstdc++-v3/include/c_global/ccomplex
@@ -41,4 +41,13 @@  extern "C++" {
 #include <complex>
 }
 
+#if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#  error "<ccomplex> is not a standard header in C++20, use <complex> instead"
+#elif __cplusplus >= 201703L && defined __DEPRECATED
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wc++23-extensions"
+#  warning "<ccomplex> is deprecated in C++17, use <complex> instead"
+#  pragma GCC diagnostic pop
+#endif
+
 #endif
diff --git a/libstdc++-v3/include/c_global/ciso646 b/libstdc++-v3/include/c_global/ciso646
index 6e26f9be12e..98ad56b12e0 100644
--- a/libstdc++-v3/include/c_global/ciso646
+++ b/libstdc++-v3/include/c_global/ciso646
@@ -38,4 +38,13 @@ 
 
 #include <bits/c++config.h>
 
+#if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#  error "<ciso646> is not a standard header in C++20, use <version> to detect implementation-specific macros"
+#elif __cplusplus >= 201703L && defined __DEPRECATED
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wc++23-extensions"
+#  warning "<ciso646> is deprecated in C++17, use <version> to detect implementation-specific macros"
+#  pragma GCC diagnostic pop
+#endif
+
 #endif
diff --git a/libstdc++-v3/include/c_global/cstdalign b/libstdc++-v3/include/c_global/cstdalign
index 4f610588425..d356c9d80a3 100644
--- a/libstdc++-v3/include/c_global/cstdalign
+++ b/libstdc++-v3/include/c_global/cstdalign
@@ -40,6 +40,14 @@ 
 #  if _GLIBCXX_HAVE_STDALIGN_H
 #    include <stdalign.h>
 #  endif
+#  if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#    error "<cstdalign> is not a standard header in C++20, remove the #include"
+#  elif __cplusplus >= 201703L && defined __DEPRECATED
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wc++23-extensions"
+#    warning "<cstdalign> is deprecated in C++17, remove the #include"
+#    pragma GCC diagnostic pop
+#  endif
 #endif
 
 #endif
diff --git a/libstdc++-v3/include/c_global/cstdbool b/libstdc++-v3/include/c_global/cstdbool
index 8d2e75df33f..dde9df71205 100644
--- a/libstdc++-v3/include/c_global/cstdbool
+++ b/libstdc++-v3/include/c_global/cstdbool
@@ -40,6 +40,14 @@ 
 #  if _GLIBCXX_HAVE_STDBOOL_H
 #    include <stdbool.h>
 #  endif
+#  if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#    error "<cstdbool> is not a standard header in C++20, remove the #include"
+#  elif __cplusplus >= 201703L && defined __DEPRECATED
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wc++23-extensions"
+#    warning "<cstdbool> is deprecated in C++17, remove the #include"
+#    pragma GCC diagnostic pop
+#  endif
 #endif
 
 #endif
diff --git a/libstdc++-v3/include/c_global/ctgmath b/libstdc++-v3/include/c_global/ctgmath
index 39c17668f16..7bc230ec21b 100644
--- a/libstdc++-v3/include/c_global/ctgmath
+++ b/libstdc++-v3/include/c_global/ctgmath
@@ -40,6 +40,14 @@ 
 extern "C++" {
 #  include <complex>
 }
+#  if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#    error "<ctgmath> is not a standard header in C++20, use <complex> or <cmath> instead"
+#  elif __cplusplus >= 201703L && defined __DEPRECATED
+#    pragma GCC diagnostic push
+#    pragma GCC diagnostic ignored "-Wc++23-extensions"
+#    warning "<ctgmath> is deprecated in C++17, use <complex> or <cmath> instead"
+#    pragma GCC diagnostic pop
+#  endif
 #endif
 
 #endif
diff --git a/libstdc++-v3/include/c_std/ciso646 b/libstdc++-v3/include/c_std/ciso646
index 7971f0d0c31..d0f7445fa44 100644
--- a/libstdc++-v3/include/c_std/ciso646
+++ b/libstdc++-v3/include/c_std/ciso646
@@ -37,4 +37,14 @@ 
 #endif
 
 #include <bits/c++config.h>
+
+#if __cplusplus >= 202002L && ! _GLIBCXX_USE_DEPRECATED
+#  error "<ciso646> is not a standard header in C++20, use <version> to detect implementation-specific macros"
+#elif __cplusplus >= 201703L && defined __DEPRECATED
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wc++23-extensions"
+#  warning "<ciso646> is deprecated in C++17, use <version> to detect implementation-specific macros"
+#  pragma GCC diagnostic pop
+#endif
+
 #endif
diff --git a/libstdc++-v3/include/precompiled/stdc++.h b/libstdc++-v3/include/precompiled/stdc++.h
index 3eef20d1645..89917106bac 100644
--- a/libstdc++-v3/include/precompiled/stdc++.h
+++ b/libstdc++-v3/include/precompiled/stdc++.h
@@ -34,7 +34,6 @@ 
 #endif
 #include <cctype>
 #include <cfloat>
-#include <ciso646>
 #include <climits>
 #include <csetjmp>
 #include <cstdarg>
@@ -43,6 +42,9 @@ 
 
 #if __cplusplus >= 201103L
 #include <cstdint>
+#if __cplusplus < 201703L
+#include <ciso646>
+#endif
 #endif
 
 // C++
@@ -108,7 +110,6 @@ 
 #include <cctype>
 #include <cerrno>
 #include <cfloat>
-#include <ciso646>
 #include <climits>
 #include <clocale>
 #include <cmath>
@@ -124,14 +125,16 @@ 
 #include <cwctype>
 
 #if __cplusplus >= 201103L
-#include <ccomplex>
 #include <cfenv>
 #include <cinttypes>
+#include <cstdint>
+#include <cuchar>
+#if __cplusplus < 201703L
+#include <ccomplex>
 #include <cstdalign>
 #include <cstdbool>
-#include <cstdint>
 #include <ctgmath>
-#include <cuchar>
+#endif
 #endif
 
 // C++
diff --git a/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.cc b/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.cc
new file mode 100644
index 00000000000..ab3a041de06
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.cc
@@ -0,0 +1,51 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated -fno-operator-names" }
+// { dg-do preprocess }
+
+#include <ciso646>
+
+// { dg-warning "deprecated" "" { target c++17_only } 0 }
+// { dg-error "not a standard header" "" { target c++20 } 0 }
+
+#ifdef and
+# error "The header <ciso646> defines a macro named and"
+#endif
+
+#ifdef and_eq
+# error "The header <ciso646> defines a macro named and_eq"
+#endif
+
+#ifdef bitand
+# error "The header <ciso646> defines a macro named bitand"
+#endif
+
+#ifdef bitor
+# error "The header <ciso646> defines a macro named bitor"
+#endif
+
+#ifdef compl
+# error "The header <ciso646> defines a macro named compl"
+#endif
+
+#ifdef not
+# error "The header <ciso646> defines a macro named not"
+#endif
+
+#ifdef not_eq
+# error "The header <ciso646> defines a macro named not_eq"
+#endif
+
+#ifdef or
+# error "The header <ciso646> defines a macro named or"
+#endif
+
+#ifdef or_eq
+# error "The header <ciso646> defines a macro named or_eq"
+#endif
+
+#ifdef xor
+# error "The header <ciso646> defines a macro named xor"
+#endif
+
+#ifdef xor_eq
+# error "The header <ciso646> defines a macro named xor_eq"
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.h.cc b/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.h.cc
new file mode 100644
index 00000000000..a70c18de918
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/headers/ciso646/macros.h.cc
@@ -0,0 +1,49 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated -fno-operator-names" }
+// { dg-do preprocess }
+// { dg-bogus "deprecated" "C++17 deprecated <ciso646> but not <iso646.h>" }
+
+#include <iso646.h>
+
+#ifdef and
+# error "The header <iso646.h> defines a macro named and"
+#endif
+
+#ifdef and_eq
+# error "The header <iso646.h> defines a macro named and_eq"
+#endif
+
+#ifdef bitand
+# error "The header <iso646.h> defines a macro named bitand"
+#endif
+
+#ifdef bitor
+# error "The header <iso646.h> defines a macro named bitor"
+#endif
+
+#ifdef compl
+# error "The header <iso646.h> defines a macro named compl"
+#endif
+
+#ifdef not
+# error "The header <iso646.h> defines a macro named not"
+#endif
+
+#ifdef not_eq
+# error "The header <iso646.h> defines a macro named not_eq"
+#endif
+
+#ifdef or
+# error "The header <iso646.h> defines a macro named or"
+#endif
+
+#ifdef or_eq
+# error "The header <iso646.h> defines a macro named or_eq"
+#endif
+
+#ifdef xor
+# error "The header <iso646.h> defines a macro named xor"
+#endif
+
+#ifdef xor_eq
+# error "The header <iso646.h> defines a macro named xor_eq"
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.cc b/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.cc
index c50c921cd59..793cd26dfa8 100644
--- a/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.cc
+++ b/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.cc
@@ -1,8 +1,13 @@ 
-// { dg-options "-D_GLIBCXX_USE_DEPRECATED=1 -Wno-deprecated" }
-// { dg-do preprocess { target c++11 } }
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do preprocess }
 
 #include <cstdalign>
 
+// { dg-error "ISO C.. 2011" "" { target c++98_only } 0 }
+// { dg-warning "deprecated" "" { target c++17_only } 0 }
+// { dg-error "not a standard header" "" { target c++20 } 0 }
+
+#if __cplusplus >= 201103L
 #ifndef __alignas_is_defined
 # error "The header <cstdalign> fails to define a macro named  __alignas_is_defined"
 #elif __alignas_is_defined != 1
@@ -22,3 +27,4 @@ 
 #ifdef alignof
 # error "The header <cstdalign> defines a macro named alignof"
 #endif
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.h.cc b/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.h.cc
new file mode 100644
index 00000000000..78f41ae02e8
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/headers/cstdalign/macros.h.cc
@@ -0,0 +1,25 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do preprocess { target c++11 } }
+// { dg-bogus "deprecated" "C++17 deprecated <cstdalign> but not <stdalign.h>" }
+
+#include <stdalign.h>
+
+#ifndef __alignas_is_defined
+# error "The header <stdalign.h> fails to define a macro named  __alignas_is_defined"
+#elif __alignas_is_defined != 1
+# error "__alignas_is_defined is not defined to 1 in <stdalign.h>"
+#endif
+
+#ifndef __alignof_is_defined
+# error "The header <stdalign.h> fails to define a macro named __alignof_is_defined"
+#elif __alignof_is_defined != 1
+# error "__alignof_is_defined is not defined to 1 in <stdalign.h>"
+#endif
+
+#ifdef alignas
+# error "The header <stdalign.h> defines a macro named alignas"
+#endif
+
+#ifdef alignof
+# error "The header <stdalign.h> defines a macro named alignof"
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc b/libstdc++-v3/testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc
deleted file mode 100644
index 14694f034e6..00000000000
--- a/libstdc++-v3/testsuite/18_support/headers/cstdalign/std_c++0x_neg.cc
+++ /dev/null
@@ -1,24 +0,0 @@ 
-// { dg-options "-std=gnu++98" }
-// { dg-do compile { target c++98_only } }
-
-// Copyright (C) 2011-2024 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <cstdalign>
-
-// { dg-error "ISO C.. 2011" "" { target *-*-* } 32 }
-
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.cc b/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.cc
index e0afc26e458..658a02a4565 100644
--- a/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.cc
+++ b/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.cc
@@ -1,4 +1,5 @@ 
-// { dg-do compile { target c++11 } }
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do preprocess }
 
 // Copyright (C) 2012-2024 Free Software Foundation, Inc.
 //
@@ -19,6 +20,11 @@ 
 
 #include <cstdbool>
 
+// { dg-error "ISO C.. 2011" "" { target c++98_only } 0 }
+// { dg-warning "deprecated" "" { target c++17_only } 0 }
+// { dg-error "not a standard header" "" { target c++20 } 0 }
+
+#if __cplusplus >= 201103L
 #ifndef __bool_true_false_are_defined
 # error "The header <cstdbool> fails to define a macro named __bool_true_false_are_defined"
 #endif
@@ -34,3 +40,4 @@ 
 #ifdef false
 # error "The header <cstdbool> defines a macro named false"
 #endif
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.h.cc b/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.h.cc
new file mode 100644
index 00000000000..a3c0f9a0aec
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/headers/cstdbool/macros.h.cc
@@ -0,0 +1,21 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do preprocess { target c++11 } }
+// { dg-bogus "deprecated" "C++17 deprecated <cstdbool> but not <stdbool.h>" }
+
+#include <stdbool.h>
+
+#ifndef __bool_true_false_are_defined
+# error "The header <stdbool.h> fails to define a macro named __bool_true_false_are_defined"
+#endif
+
+#ifdef bool
+# error "The header <stdbool.h> defines a macro named bool"
+#endif
+
+#ifdef true
+# error "The header <stdbool.h> defines a macro named true"
+#endif
+
+#ifdef false
+# error "The header <stdbool.h> defines a macro named false"
+#endif
diff --git a/libstdc++-v3/testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc b/libstdc++-v3/testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc
deleted file mode 100644
index 5b8c5688877..00000000000
--- a/libstdc++-v3/testsuite/18_support/headers/cstdbool/std_c++0x_neg.cc
+++ /dev/null
@@ -1,26 +0,0 @@ 
-// { dg-options "-std=gnu++98" }
-// { dg-do compile { target c++98_only } }
-
-// Copyright (C) 2007-2024 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <cstdbool>
-
-// { dg-error "ISO C.. 2011" "" { target *-*-* } 32 }
-
-
-
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.cc b/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.cc
new file mode 100644
index 00000000000..d6c33781ae5
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.cc
@@ -0,0 +1,10 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do compile }
+
+#include <ccomplex>
+
+std::complex<double> d;
+
+// { dg-error "ISO C.. 2011" "" { target c++98_only } 0 }
+// { dg-warning "deprecated" "" { target c++17_only } 0 }
+// { dg-error "not a standard header" "" { target c++20 } 0 }
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.h.cc b/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.h.cc
new file mode 100644
index 00000000000..318b78ee89e
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/complex.h.cc
@@ -0,0 +1,10 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do compile }
+// { dg-bogus "deprecated" "C++17 deprecated <ccomplex> but not <complex.h>" }
+
+#include <complex.h>
+
+#if __cplusplus < 201103L
+# undef complex
+#endif
+std::complex<double> d; // { dg-error "does not name a template" "" { target c++98_only } 0 }
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc b/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc
deleted file mode 100644
index 16c623b25b0..00000000000
--- a/libstdc++-v3/testsuite/26_numerics/headers/ccomplex/std_c++0x_neg.cc
+++ /dev/null
@@ -1,26 +0,0 @@ 
-// { dg-options "-std=gnu++98" }
-// { dg-do compile { target c++98_only } }
-
-// Copyright (C) 2007-2024 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <ccomplex>
-
-// { dg-error "ISO C.. 2011" "" { target *-*-* } 32 }
-
-
-
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.cc b/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.cc
index a2c4a55c89b..ef2bbd0e20a 100644
--- a/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.cc
+++ b/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.cc
@@ -15,8 +15,13 @@ 
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 
-// { dg-do compile { target c++11 } }
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do compile }
 
 #include <ctgmath>
 
-std::complex<double> d;
+std::complex<double> d; // { dg-error "does not name a template" "" { target c++98_only } 0 }
+
+// { dg-error "ISO C.. 2011" "" { target c++98_only } 0 }
+// { dg-warning "deprecated" "" { target c++17_only } 0 }
+// { dg-error "not a standard header" "" { target c++20 } 0 }
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.h.cc b/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.h.cc
new file mode 100644
index 00000000000..fd6847bff4f
--- /dev/null
+++ b/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/complex.h.cc
@@ -0,0 +1,10 @@ 
+// { dg-options "-D_GLIBCXX_USE_DEPRECATED=0 -Wdeprecated" }
+// { dg-do compile }
+// { dg-bogus "deprecated" "C++17 deprecated <ctgmath> but not <tgmath.h>" }
+
+#include <tgmath.h>
+
+#if __cplusplus < 201103L
+# undef complex
+#endif
+std::complex<double> d; // { dg-error "does not name a template" "" { target c++98_only } 0 }
diff --git a/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc b/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc
deleted file mode 100644
index d693c8b23ed..00000000000
--- a/libstdc++-v3/testsuite/26_numerics/headers/ctgmath/std_c++0x_neg.cc
+++ /dev/null
@@ -1,26 +0,0 @@ 
-// { dg-options "-std=gnu++98" }
-// { dg-do compile { target c++98_only } }
-
-// Copyright (C) 2007-2024 Free Software Foundation, Inc.
-//
-// This file is part of the GNU ISO C++ Library.  This library is free
-// software; you can redistribute it and/or modify it under the
-// terms of the GNU General Public License as published by the
-// Free Software Foundation; either version 3, or (at your option)
-// any later version.
-
-// This library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License along
-// with this library; see the file COPYING3.  If not see
-// <http://www.gnu.org/licenses/>.
-
-#include <ctgmath>
-
-// { dg-error "ISO C.. 2011" "" { target *-*-* } 32 }
-
-
-
diff --git a/libstdc++-v3/testsuite/27_io/objects/char/1.cc b/libstdc++-v3/testsuite/27_io/objects/char/1.cc
index 9fc9244baf4..d50b3884702 100644
--- a/libstdc++-v3/testsuite/27_io/objects/char/1.cc
+++ b/libstdc++-v3/testsuite/27_io/objects/char/1.cc
@@ -53,7 +53,6 @@ 
 #include <cctype>
 #include <cerrno>
 #include <cfloat>
-#include <ciso646>
 #include <climits>
 #include <clocale>
 #include <cmath>
diff --git a/libstdc++-v3/testsuite/27_io/objects/wchar_t/1.cc b/libstdc++-v3/testsuite/27_io/objects/wchar_t/1.cc
index 23b2168805d..c2f3643b4e5 100644
--- a/libstdc++-v3/testsuite/27_io/objects/wchar_t/1.cc
+++ b/libstdc++-v3/testsuite/27_io/objects/wchar_t/1.cc
@@ -53,7 +53,6 @@ 
 #include <cctype>
 #include <cerrno>
 #include <cfloat>
-#include <ciso646>
 #include <climits>
 #include <clocale>
 #include <cmath>