8 files changed, 72 insertions, 9 deletions
diff --git a/gcc/c-family/c-cppbuiltin.cc b/gcc/c-family/c-cppbuiltin.cc
index a1557eb..b709f84 100644
--- a/gcc/c-family/c-cppbuiltin.cc
+++ b/gcc/c-family/c-cppbuiltin.cc
@@ -1112,7 +1112,7 @@ c_cpp_builtins (cpp_reader *pfile)
       if (flag_threadsafe_statics)
 	cpp_define (pfile, "__cpp_threadsafe_static_init=200806L");
       if (flag_char8_t)
-        cpp_define (pfile, "__cpp_char8_t=201811L");
+	cpp_define (pfile, "__cpp_char8_t=202207L");
 #ifndef THREAD_MODEL_SPEC
       /* Targets that define THREAD_MODEL_SPEC need to define
 	 __STDCPP_THREADS__ in their config/XXX/XXX-c.c themselves.  */
diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
index 75fd0e2..739097a 100644
--- a/gcc/cp/typeck2.cc
+++ b/gcc/cp/typeck2.cc
@@ -1118,6 +1118,15 @@ array_string_literal_compatible_p (tree type, tree init)
   if (ordinary_char_type_p (to_char_type)
       && ordinary_char_type_p (from_char_type))
     return true;
+
+  /* P2513 (C++20/C++23): "an array of char or unsigned char may
+     be initialized by a UTF-8 string literal, or by such a string
+     literal enclosed in braces."  */
+  if (from_char_type == char8_type_node
+      && (to_char_type == char_type_node
+	  || to_char_type == unsigned_char_type_node))
+    return true;
+
   return false;
 }
 
diff --git a/gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C b/gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C
index d3e4072..0537e1d 100644
--- a/gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C
+++ b/gcc/testsuite/g++.dg/cpp23/feat-cxx2b.C
@@ -504,8 +504,8 @@
 
 #ifndef __cpp_char8_t
 #  error "__cpp_char8_t"
-#elif __cpp_char8_t != 201811
-#  error "__cpp_char8_t != 201811"
+#elif __cpp_char8_t != 202207
+#  error "__cpp_char8_t != 202207"
 #endif
 
 #ifndef __cpp_designated_initializers
diff --git a/gcc/testsuite/g++.dg/cpp2a/char8_t3.C b/gcc/testsuite/g++.dg/cpp2a/char8_t3.C
new file mode 100644
index 0000000..071a718
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/char8_t3.C
@@ -0,0 +1,37 @@
+// PR c++/106656 - P2513 - char8_t Compatibility and Portability Fixes
+// { dg-do compile { target c++20 } }
+
+const char *p1 = u8""; // { dg-error "invalid conversion" }
+const unsigned char *p2 = u8""; // { dg-error "invalid conversion" }
+const signed char *p3 = u8""; // { dg-error "invalid conversion" }
+const char *p4 = { u8"" }; // { dg-error "invalid conversion" }
+const unsigned char *p5 = { u8"" }; // { dg-error "invalid conversion" }
+const signed char *p6 = { u8"" }; // { dg-error "invalid conversion" }
+const char *p7 = static_cast<const char *>(u8""); // { dg-error "invalid" }
+const char a1[] = u8"text";
+const unsigned char a2[] = u8"";
+const signed char a3[] = u8""; // { dg-error "cannot initialize array" }
+const char a4[] = { u8"text" };
+const unsigned char a5[] = { u8"" };
+const signed char a6[] = { u8"" }; // { dg-error "cannot initialize array" }
+
+const char *
+resource_id ()
+{
+  static const char res_id[] = u8"";
+  return res_id;
+}
+
+const char8_t x[] = "fail"; // { dg-error "cannot initialize array" }
+
+void fn (const char a[]);
+void
+g ()
+{
+  fn (u8"z"); // { dg-error "invalid conversion" }
+}
+
+char c = u8'c';
+unsigned char uc = u8'c';
+signed char sc = u8'c';
+char8_t c8 = 'c';
diff --git a/gcc/testsuite/g++.dg/cpp2a/char8_t4.C b/gcc/testsuite/g++.dg/cpp2a/char8_t4.C
new file mode 100644
index 0000000..c18081b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/char8_t4.C
@@ -0,0 +1,17 @@
+// PR c++/106656 - P2513 - char8_t Compatibility and Portability Fixes
+// { dg-do compile { target c++20 } }
+// [diff.cpp20.dcl]
+
+struct A {
+	char8_t s[10];
+};
+struct B {
+	char s[10];
+};
+
+void f(A);
+void f(B);
+
+int main() {
+	f({u8""}); // { dg-error "ambiguous" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C b/gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
index c65ea6b..02f3a37 100644
--- a/gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
+++ b/gcc/testsuite/g++.dg/cpp2a/feat-cxx2a.C
@@ -504,8 +504,8 @@
 
 #ifndef __cpp_char8_t
 #  error "__cpp_char8_t"
-#elif __cpp_char8_t != 201811
-#  error "__cpp_char8_t != 201811"
+#elif __cpp_char8_t != 202207
+#  error "__cpp_char8_t != 202207"
 #endif
 
 #ifndef __cpp_designated_initializers
diff --git a/gcc/testsuite/g++.dg/ext/char8_t-feature-test-macro-2.C b/gcc/testsuite/g++.dg/ext/char8_t-feature-test-macro-2.C
index df1063f..2d0f904 100644
--- a/gcc/testsuite/g++.dg/ext/char8_t-feature-test-macro-2.C
+++ b/gcc/testsuite/g++.dg/ext/char8_t-feature-test-macro-2.C
@@ -5,6 +5,6 @@
 
 #if !defined(__cpp_char8_t)
 #  error __cpp_char8_t is not defined!
-#elif __cpp_char8_t != 201811
-#  error __cpp_char8_t != 201811
+#elif __cpp_char8_t != 202207
+#  error __cpp_char8_t != 202207
 #endif
diff --git a/gcc/testsuite/g++.dg/ext/char8_t-init-2.C b/gcc/testsuite/g++.dg/ext/char8_t-init-2.C
index c713bc1..02a96ff 100644
--- a/gcc/testsuite/g++.dg/ext/char8_t-init-2.C
+++ b/gcc/testsuite/g++.dg/ext/char8_t-init-2.C
@@ -21,7 +21,7 @@ const char8_t (&rca4)[2] = u8"x";
 const char8_t (&rca5)[2] = u"x"; // { dg-error "invalid initialization of reference of type .const char8_t ....... from expression of type .const char16_t ...." "char8_t" }
 
 char ca1[] = "x";
-char ca2[] = u8"x"; // { dg-error "from a string literal with type array of .char8_t." "char8_t" }
+char ca2[] = u8"x";
 char8_t ca3[] = "x"; // { dg-error "from a string literal with type array of .char." "char8_t" }
 char8_t ca4[] = u8"x";
 char8_t ca5[] = u"x"; // { dg-error "from a string literal with type array of .char16_t." "char8_t" }
@@ -30,4 +30,4 @@ signed char sca1[] = "x";
 signed char sca2[] = u8"x"; // { dg-error "from a string literal with type array of .char8_t." "char8_t" }
 
 unsigned char uca1[] = "x";
-unsigned char uca2[] = u8"x"; // { dg-error "from a string literal with type array of .char8_t." "char8_t" }
+unsigned char uca2[] = u8"x";