Derived from the changes that added C++2a support in 2017.
https://gcc.gnu.org/g:026a79f70cf33f836ea5275eda72d4870a3041e5
No C++2b features are added here.
Use of -std=c++2b sets __cplusplus to 202101L.
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5541e694bb3..3a0d452b62b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2021-01-08 Paul Fee <paul.f....@gmail.com>
+
+ Add support for -std=c++2b
+ * doc/cpp.texi (__cplusplus): Document value for -std=c++2b
+ or -std=gnu+2b.
+ * doc/invoke.texi: Document -std=c++2b and -std=gnu++2b.
+
2021-01-06 Vladimir N. Makarov <vmaka...@redhat.com>
PR rtl-optimization/97978
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 654c2360085..9af4050fdc8 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,13 @@
+2021-01-08 Paul Fee <paul.f....@gmail.com>
+
+ Add support for -std=c++2b
+ * c-common.h (cxx_dialect): Add cxx2b as a dialect.
+ * c.opt: Add options for -std=c++2b and -std=gnu++2b.
+ * c-opts.c (set_std_cxx2b): New.
+ (c_common_handle_option): Set options when -std=c++2b is enabled.
+ (c_common_post_options): Adjust comments.
+ (set_std_cxx20): Likewise.
+
2021-01-06 Martin Sebor <mse...@redhat.com>
PR c++/95768
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index a65c78f7240..cfa056a6e28 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -738,7 +738,9 @@ enum cxx_dialect {
/* C++17 */
cxx17,
/* C++20 */
- cxx20
+ cxx20,
+ /* C++23? */
+ cxx2b
};
/* The C++ dialect being used. C++98 is the default. */
diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 3cdf41bc6e2..2612fac5a62 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -113,6 +113,7 @@ static void set_std_cxx11 (int);
static void set_std_cxx14 (int);
static void set_std_cxx17 (int);
static void set_std_cxx20 (int);
+static void set_std_cxx2b (int);
static void set_std_c89 (int, int);
static void set_std_c99 (int);
static void set_std_c11 (int);
@@ -649,6 +650,12 @@ c_common_handle_option (size_t scode, const char
*arg, HOST_WIDE_INT value,
set_std_cxx20 (code == OPT_std_c__20 /* ISO */);
break;
+ case OPT_std_c__2b:
+ case OPT_std_gnu__2b:
+ if (!preprocessing_asm_p)
+ set_std_cxx2b (code == OPT_std_c__2b /* ISO */);
+ break;
+
case OPT_std_c90:
case OPT_std_iso9899_199409:
if (!preprocessing_asm_p)
@@ -1019,7 +1026,7 @@ c_common_post_options (const char **pfilename)
warn_narrowing = 1;
/* Unless -f{,no-}ext-numeric-literals has been used explicitly,
- for -std=c++{11,14,17,2a} default to -fno-ext-numeric-literals. */
+ for -std=c++{11,14,17,20,2b} default to -fno-ext-numeric-literals. */
if (flag_iso && !global_options_set.x_flag_ext_numeric_literals)
cpp_opts->ext_numeric_literals = 0;
}
@@ -1763,7 +1770,7 @@ set_std_cxx20 (int iso)
flag_no_gnu_keywords = iso;
flag_no_nonansi_builtin = iso;
flag_iso = iso;
- /* C++17 includes the C11 standard library. */
+ /* C++20 includes the C11 standard library. */
flag_isoc94 = 1;
flag_isoc99 = 1;
flag_isoc11 = 1;
@@ -1773,6 +1780,24 @@ set_std_cxx20 (int iso)
lang_hooks.name = "GNU C++20";
}
+/* Set the C++ 2020 standard (without GNU extensions if ISO). */
+static void
+set_std_cxx2b (int iso)
+{
+ cpp_set_lang (parse_in, iso ? CLK_CXX2B: CLK_GNUCXX2B);
+ flag_no_gnu_keywords = iso;
+ flag_no_nonansi_builtin = iso;
+ flag_iso = iso;
+ /* C++2b includes the C11 standard library. */
+ flag_isoc94 = 1;
+ flag_isoc99 = 1;
+ flag_isoc11 = 1;
+ /* C++2b includes coroutines. */
+ flag_coroutines = true;
+ cxx_dialect = cxx2b;
+ lang_hooks.name = "GNU C++20"; /* Pretend C++20 until standardization. */
+}
+
/* Args to -d specify what to dump. Silently ignore
unrecognized options; they may be aimed at toplev.c. */
static void
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 1766364806e..3464d72591b 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -2214,6 +2214,11 @@ std=c++20
C++ ObjC++
Conform to the ISO 2020 C++ draft standard (experimental and
incomplete support).
+std=c++2b
+C++ ObjC++
+Conform to the ISO 2023 (?) C++ draft standard (experimental and
+incomplete support).
+
std=c11
C ObjC
Conform to the ISO 2011 C standard.
@@ -2292,6 +2297,11 @@ std=gnu++20
C++ ObjC++
Conform to the ISO 2020 C++ draft standard with GNU extensions
(experimental and incomplete support).
+std=gnu++2b
+C++ ObjC++
+Conform to the ISO 2023 (?) C++ draft standard with GNU extensions
(experimental
+and incomplete support).
+
std=gnu11
C ObjC
Conform to the ISO 2011 C standard with GNU extensions.
diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index 25f2625d8bd..f801024affd 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -1907,9 +1907,10 @@ selected, the value of the macro is
@code{201103L} for the 2011 C++ standard,
@code{201402L} for the 2014 C++ standard,
@code{201703L} for the 2017 C++ standard,
-or an unspecified value strictly larger than @code{201703L} for the
-experimental languages enabled by @option{-std=c++2a} and
-@option{-std=gnu++2a}.
+@code{202002L} for the 2020 C++ standard,
+or an unspecified value strictly larger than @code{202002L} for the
+experimental languages enabled by @option{-std=c++2b} and
+@option{-std=gnu++2b}.
@item __OBJC__
This macro is defined, with value 1, when the Objective-C compiler is in
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 226b8ade430..11a6e9a23c3 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2430,6 +2430,16 @@ GNU dialect of @option{-std=c++20}.
Support is experimental, and could change in incompatible ways in
future releases.
The name @samp{gnu++2a} is deprecated.
+
+@item c++2b
+The next revision of the ISO C++ standard, planned for
+2023. Support is highly experimental, and will almost certainly
+change in incompatible ways in future releases.
+
+@item gnu++2b
+GNU dialect of @option{-std=c++2b}. Support is highly experimental,
+and will almost certainly change in incompatible ways in future
+releases.
@end table
@item -fgnu89-inline
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 856b05d5727..98b9b7ab848 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,17 @@
+2021-01-08 Paul Fee <paul.f....@gmail.com>
+
+ Add support for -std=c++2b
+ * lib/target-supports.exp: (check_effective_target_c++2a_only)
+ rename to check_effective_target_c++20_only.
+ (check_effective_target_c++2a): rename to check_effective_target_c++20.
+ (check_effective_target_c++20): Return 1
+ if check_effective_target_c++20_only or
+ if check_effective_target_c++2b.
+ (check_effective_target_c++20_down): New.
+ (check_effective_target_c++2a_only): New.
+ (check_effective_target_c++2a): New.
+ * g++.dg/cpp2b/cplusplus.C: New.
+
2021-01-06 Vladimir N. Makarov <vmaka...@redhat.com>
PR rtl-optimization/97978
diff --git a/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
b/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
new file mode 100644
index 00000000000..615d9f081de
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2b/cplusplus.C
@@ -0,0 +1,4 @@
+// { dg-do compile }
+// { dg-options "-std=c++2b" }
+
+static_assert(__cplusplus > 202002L);
diff --git a/gcc/testsuite/lib/target-supports.exp
b/gcc/testsuite/lib/target-supports.exp
index 5cf0f4218a6..31be4de12a5 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -9434,7 +9434,6 @@ proc check_effective_target_c++14_only { } {
}
return 0
}
-
proc check_effective_target_c++14 { } {
if [check_effective_target_c++14_only] {
return 1
@@ -9475,7 +9474,6 @@ proc check_effective_target_c++17_only { } {
}
return 0
}
-
proc check_effective_target_c++17 { } {
if [check_effective_target_c++17_only] {
return 1
@@ -9489,12 +9487,12 @@ proc check_effective_target_c++17_down { } {
return [expr ![check_effective_target_c++2a] ]
}
-proc check_effective_target_c++2a_only { } {
+proc check_effective_target_c++20_only { } {
global cxx_default
if ![check_effective_target_c++] {
return 0
}
- if [check-flags { { } { } { -std=c++2a -std=gnu++2a -std=c++20
-std=gnu++20 } }] {
+ if [check-flags { { } { } { -std=c++20 -std=gnu++20 -std=c++2a
-std=gnu++2a } }] {
return 1
}
if { $cxx_default == "c++20" && [check-flags { { } { } { } {
-std=* } }] } {
@@ -9502,18 +9500,37 @@ proc check_effective_target_c++2a_only { } {
}
return 0
}
-proc check_effective_target_c++2a { } {
- return [check_effective_target_c++2a_only]
+proc check_effective_target_c++20 { } {
+ if [check_effective_target_c++20_only] {
+ return 1
+ }
+ return [check_effective_target_c++2b]
}
-
-proc check_effective_target_c++20_only { } {
- return [check_effective_target_c++2a_only]
+proc check_effective_target_c++20_down { } {
+ if ![check_effective_target_c++] {
+ return 0
+ }
+ return [expr ![check_effective_target_c++20] ]
}
-proc check_effective_target_c++20 { } {
- return [check_effective_target_c++2a]
+proc check_effective_target_c++2b_only { } {
+ global cxx_default
+ if ![check_effective_target_c++] {
+ return 0
+ }
+ if [check-flags { { } { } { -std=c++2b -std=gnu++2b } }] {
+ return 1
+ }
+ if { $cxx_default == "c++23" && [check-flags { { } { } { } {
-std=* } }] } {
+ return 1
+ }
+ return 0
+}
+proc check_effective_target_c++2b { } {
+ return [check_effective_target_c++2b_only]
}
+
# Check for C++ Concepts support, i.e. -fconcepts flag.
proc check_effective_target_concepts { } {
if [check_effective_target_c++2a] {
diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index e78e9a6b26a..26bd505104f 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,10 @@
+2021-01-08 Paul Fee <paul.f....@gmail.com>
+
+ Add support for -std=c++2b
+ * include/cpplib.h (c_lang): Add CXX2B and GNUCXX2B.
+ * init.c (lang_defaults): Add rows for CXX2B and GNUCXX2B.
+ (cpp_init_builtins): Set __cplusplus to 202101L for C++2b.
+
2020-12-14 Nathan Sidwell <nat...@acm.org>
* include/cpplib.h (struct cpp_macro): Add imported_p field.
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index bcc50ba45f6..c213fbac0b1 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -173,7 +173,8 @@ enum c_lang {CLK_GNUC89 = 0, CLK_GNUC99,
CLK_GNUC11, CLK_GNUC17, CLK_GNUC2X,
CLK_STDC2X,
CLK_GNUCXX, CLK_CXX98, CLK_GNUCXX11, CLK_CXX11,
CLK_GNUCXX14, CLK_CXX14, CLK_GNUCXX17, CLK_CXX17,
- CLK_GNUCXX20, CLK_CXX20, CLK_ASM};
+ CLK_GNUCXX20, CLK_CXX20, CLK_GNUCXX2B, CLK_CXX2B,
+ CLK_ASM};
/* Payload of a NUMBER, STRING, CHAR or COMMENT token. */
struct GTY(()) cpp_string {
diff --git a/libcpp/init.c b/libcpp/init.c
index a5103c4d454..dd8c66bf324 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -119,6 +119,8 @@ static const struct lang_flags lang_defaults[] =
/* CXX17 */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 0, 1, 0, 1, 0 },
/* GNUCXX20 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,
1, 0, 1, 1, 1, 0 },
/* CXX20 */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 0, 1, 1, 1, 0 },
+ /* GNUCXX2B */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1,
1, 0, 1, 1, 1, 0 },
+ /* CXX2B */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 0, 1, 1, 1, 0 },
/* ASM */ { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0 }
};
@@ -540,7 +542,10 @@ cpp_init_builtins (cpp_reader *pfile, int hosted)
if (CPP_OPTION (pfile, cplusplus))
{
- if (CPP_OPTION (pfile, lang) == CLK_CXX20
+ if (CPP_OPTION (pfile, lang) == CLK_CXX2B
+ || CPP_OPTION (pfile, lang) == CLK_GNUCXX2B)
+ _cpp_define_builtin (pfile, "__cplusplus 202101L");
+ else if (CPP_OPTION (pfile, lang) == CLK_CXX20
|| CPP_OPTION (pfile, lang) == CLK_GNUCXX20)
_cpp_define_builtin (pfile, "__cplusplus 202002L");
else if (CPP_OPTION (pfile, lang) == CLK_CXX17
