[PATCH v2] libstdc++: implement constexpr std::format
Jonathan Wakely
jwakely@redhat.com
Mon Jun 1 15:48:41 GMT 2026
On Fri, 15 May 2026 at 10:53 +0200, Tomasz Kamiński wrote:
>From: Ivan Lazaric <ivan.lazaric1@gmail.com>
>
>This patch implements constexpr formatting from P3391R2,
>and introduces the constexpr_format feature-test macro.
>Since pre-cxx11 cow_string is not constexpr-enabled,
>only exposing the feature-test macro under cxx11 ABI.
>
>Add `__format::__toupper_numeric` function that work in constexpr.
>It is not fully general, but `<format>` doesn't need all uppercasing.
>
>The `__write_escaped_ascii` is not marked constexpr, to enable
>futhure improvement for non-unicode literal encodings (for example
>using `iconv`).
>
>Update `__check_dynamic_spec` to check if `__args` is run, to
>accomodate for dynamic_format or vformat invoked at compile time.
>
>Mark `basic_format_string` consteval constructor noexcept,
>since exceptions are now constexpr, and the standard mandates
>failure to parse to be non-catchable ill-formed.
>https://eel.is/c++draft/format#fmt.string-3
>> Remarks: A call to this function is not a core constant expression
>> ([expr.const]) unless there exist args of types Args such that
>> str is a format string for args.
>
>Update some formatting tests to test constexpr as well,
>and introduce a dedicated smoke test for constexpr formatting.
>
>libstdc++-v3/include/ChangeLog:
There is no ChangeLog file in the include directory, nor in the
testsuite directory. There is only libstdc++-v3/ChangeLog, so
everything should be a single ChangeLog entry.
>
> * bits/version.def (constexpr_exceptions): Move before
> format.
> (constexpr_format): Define.
> * bits/version.h: Regenerate.
> * std/format (_GLIBCXX_CONSTEXPR_FORMAT): Define and apply
> to all of functions except __write_escaped_ascii and
> __formatter_fp members.
> (_GLIBCXX_CONSTEXPR_FORMAT_ERROR): Replace with
> _GLIBCXX_CONSTEXPR_FORMAT.
> (basic_format_string::basic_format_string(const _Tp&)):
> Mark as noexcept.
> (__format::__toupper_numeric): Define.
> (__formatter_int::format): Use __format::__toupper_numeric
> and replace __builtin_memcpy with ranges::copy.
> (__formatter_fp::format): Use __format::__toupper_numeric.
> (__formatter_ptr::format): Avoid reinterpret_cast for
> null-pointer value to support std::nullptr_t formatting.
> (__format::__do_vformat_to): Replace __builtin_memcpy with
> ranges::copy.
> (basic_format_parse_context::__check_dynamic_spec):
> Skip checks if __args pointer is null.
>
>libstdc++-v3/testsuite/ChangeLog:
>
> * std/format/arguments/args_neg.cc: Diagnostics change.
> * std/format/constexpr.cc: New test.
> * std/format/debug.cc: Test at compile-time in C++26 and
> update iteration limit for paddding tests.
> * std/format/tuple.cc: Likewise.
> * std/format/functions/format.cc: Test at compile-time in C++26.
> * std/format/functions/format_to.cc: Likewise.
> * std/format/functions/size.cc: Likewise.
> * std/format/ranges/format_kind.cc: Likewise.
> * std/format/ranges/formatter.cc: Likewise.
> * std/format/ranges/sequence.cc: Likewise.
> * std/format/runtime_format.cc: Likewise.
> * std/format/string.cc: Likewise.
> * std/time/format/data_not_present_neg.cc: Diagnostics change.
>
>Co-authored-by: Tomasz Kamiński <tkaminsk@redhat.com>
>Signed-off-by: Ivan Lazaric <ivan.lazaric1@gmail.com>
>---
>v2 changes:
> - updates changelog
> - remove constexpr support for __write_escaped_ascii, they
> will be follow up patch enabling it for common case
> - removes workaroung for _Ptr_sink in vformat_to_n,
> after Jakub's make it constexpr in PR124347, clang
> support it in C++|23 or later.
> - constexpr_format now depend on constexpr_exceptions,
> (they were moved beforein file), and make
> __cpp_lib_contexp_format defined by <format>
> - replaced _GLIBCXX_CONSTEXPR_FORMAT_ERROR with
> simply _GLIBCXX_CONSTEXPR_FORMAT
> - increase constexpr iterations limit for also for tuple.cc,
> so transcoding finishes
> - removed ctype include was we use to_upper_numeric.
>
>Tested on x86_64-linux. OK for trunk?
>
> libstdc++-v3/include/bits/version.def | 32 +-
> libstdc++-v3/include/bits/version.h | 30 +-
> libstdc++-v3/include/std/format | 394 +++++++++++-------
> .../std/format/arguments/args_neg.cc | 4 +-
> .../testsuite/std/format/constexpr.cc | 166 ++++++++
> libstdc++-v3/testsuite/std/format/debug.cc | 83 ++--
> .../testsuite/std/format/dynamic_format.cc | 25 +-
> .../testsuite/std/format/functions/format.cc | 281 +++++++------
> .../std/format/functions/format_to.cc | 58 ++-
> .../testsuite/std/format/functions/size.cc | 23 +-
> .../std/format/ranges/format_kind.cc | 15 +-
> .../testsuite/std/format/ranges/formatter.cc | 37 +-
> .../testsuite/std/format/ranges/sequence.cc | 64 ++-
> libstdc++-v3/testsuite/std/format/string.cc | 59 ++-
> libstdc++-v3/testsuite/std/format/tuple.cc | 72 +++-
> .../std/time/format/data_not_present_neg.cc | 3 +-
> 16 files changed, 932 insertions(+), 414 deletions(-)
> create mode 100644 libstdc++-v3/testsuite/std/format/constexpr.cc
>
>diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
>index 6d789987642..a6adaef42a0 100644
>--- a/libstdc++-v3/include/bits/version.def
>+++ b/libstdc++-v3/include/bits/version.def
>@@ -1328,6 +1328,16 @@ ftms = {
> };
> };
>
>+ftms = {
>+ name = constexpr_exceptions;
>+ values = {
>+ v = 202502;
>+ cxxmin = 26;
>+ extra_cond = "__cpp_constexpr_exceptions >= 202411L";
>+ cxx11abi = yes;
>+ };
>+};
>+
> ftms = {
> name = format;
> // 202305 P2757R3 Type checking format args
>@@ -1351,6 +1361,18 @@ ftms = {
> };
> };
>
>+ftms = {
>+ name = constexpr_format;
>+ // 202511 P3391R2 constexpr std::format
>+ values = {
>+ v = 202511;
>+ cxxmin = 26;
>+ hosted = yes;
>+ extra_cond = "__cpp_lib_constexpr_exceptions >= 202502L";
>+ cxx11abi = yes;
>+ };
>+};
>+
> ftms = {
> name = format_uchar;
> values = {
>@@ -2325,16 +2347,6 @@ ftms = {
> };
> };
>
>-ftms = {
>- name = constexpr_exceptions;
>- values = {
>- v = 202502;
>- cxxmin = 26;
>- extra_cond = "__cpp_constexpr_exceptions >= 202411L";
>- cxx11abi = yes;
>- };
>-};
>-
> ftms = {
> name = philox_engine;
> values = {
>diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
>index c44fe07ec60..7c24bcc5f44 100644
>--- a/libstdc++-v3/include/bits/version.h
>+++ b/libstdc++-v3/include/bits/version.h
>@@ -1476,6 +1476,16 @@
> #endif /* !defined(__cpp_lib_barrier) */
> #undef __glibcxx_want_barrier
>
>+#if !defined(__cpp_lib_constexpr_exceptions)
>+# if (__cplusplus > 202302L) && _GLIBCXX_USE_CXX11_ABI && (__cpp_constexpr_exceptions >= 202411L)
>+# define __glibcxx_constexpr_exceptions 202502L
>+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_exceptions)
>+# define __cpp_lib_constexpr_exceptions 202502L
>+# endif
>+# endif
>+#endif /* !defined(__cpp_lib_constexpr_exceptions) */
>+#undef __glibcxx_want_constexpr_exceptions
>+
> #if !defined(__cpp_lib_format)
> # if (__cplusplus > 202302L) && _GLIBCXX_HOSTED
> # define __glibcxx_format 202603L
>@@ -1491,6 +1501,16 @@
> #endif /* !defined(__cpp_lib_format) */
> #undef __glibcxx_want_format
>
>+#if !defined(__cpp_lib_constexpr_format)
>+# if (__cplusplus > 202302L) && _GLIBCXX_USE_CXX11_ABI && _GLIBCXX_HOSTED && (__cpp_lib_constexpr_exceptions >= 202502L)
>+# define __glibcxx_constexpr_format 202511L
>+# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_format)
>+# define __cpp_lib_constexpr_format 202511L
>+# endif
>+# endif
>+#endif /* !defined(__cpp_lib_constexpr_format) */
>+#undef __glibcxx_want_constexpr_format
>+
> #if !defined(__cpp_lib_format_uchar)
> # if (__cplusplus >= 202002L) && _GLIBCXX_HOSTED
> # define __glibcxx_format_uchar 202311L
>@@ -2586,16 +2606,6 @@
> #endif /* !defined(__cpp_lib_bitset) */
> #undef __glibcxx_want_bitset
>
>-#if !defined(__cpp_lib_constexpr_exceptions)
>-# if (__cplusplus > 202302L) && _GLIBCXX_USE_CXX11_ABI && (__cpp_constexpr_exceptions >= 202411L)
>-# define __glibcxx_constexpr_exceptions 202502L
>-# if defined(__glibcxx_want_all) || defined(__glibcxx_want_constexpr_exceptions)
>-# define __cpp_lib_constexpr_exceptions 202502L
>-# endif
>-# endif
>-#endif /* !defined(__cpp_lib_constexpr_exceptions) */
>-#undef __glibcxx_want_constexpr_exceptions
>-
> #if !defined(__cpp_lib_philox_engine)
> # if (__cplusplus > 202302L)
> # define __glibcxx_philox_engine 202406L
>diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
>index 0f20fcc8d88..fe0f611b833 100644
>--- a/libstdc++-v3/include/std/format
>+++ b/libstdc++-v3/include/std/format
>@@ -39,6 +39,7 @@
> #define __glibcxx_want_format_ranges
> #define __glibcxx_want_format_uchar
> #define __glibcxx_want_constexpr_exceptions
>+#define __glibcxx_want_constexpr_format
> #include <bits/version.h>
>
> #ifdef __cpp_lib_format // C++ >= 20 && HOSTED
>@@ -63,8 +64,10 @@
> #include <bits/utility.h> // tuple_size_v
> #include <ext/numeric_traits.h> // __int_traits
>
>-#if !__has_builtin(__builtin_toupper)
>-# include <cctype>
>+#ifdef __glibcxx_constexpr_format // C++ >= 26 && HOSTED && CXX11 strings
>+# define _GLIBCXX_CONSTEXPR_FORMAT constexpr
>+#else
>+# define _GLIBCXX_CONSTEXPR_FORMAT
> #endif
>
> #pragma GCC diagnostic push
>@@ -128,6 +131,7 @@ namespace __format
> struct _Dynamic_format_string
> {
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Dynamic_format_string(basic_string_view<_CharT> __s) noexcept
> : _M_str(__s) { }
>
>@@ -170,9 +174,10 @@ namespace __format
> template<typename _Tp>
> requires convertible_to<const _Tp&, basic_string_view<_CharT>>
> consteval
>- basic_format_string(const _Tp& __s);
>+ basic_format_string(const _Tp& __s) noexcept;
>
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_string(__format::_Dynamic_format_string<_CharT> __s) noexcept
> : _M_str(__s._M_str)
> { }
>@@ -197,13 +202,13 @@ namespace __format
>
> #if __cpp_lib_format >= 202603L // >= C++26
> [[__gnu__::__always_inline__]]
>- inline __format::_Dynamic_format_string<char>
>+ inline _GLIBCXX_CONSTEXPR_FORMAT __format::_Dynamic_format_string<char>
> dynamic_format(string_view __fmt) noexcept
> { return __fmt; }
>
> #ifdef _GLIBCXX_USE_WCHAR_T
> [[__gnu__::__always_inline__]]
>- inline __format::_Dynamic_format_string<wchar_t>
>+ inline _GLIBCXX_CONSTEXPR_FORMAT __format::_Dynamic_format_string<wchar_t>
> dynamic_format(wstring_view __fmt) noexcept
> { return __fmt; }
> #endif
>@@ -220,56 +225,51 @@ namespace __format
> formatter& operator=(const formatter&) = delete;
> };
>
>-#if __cpp_lib_constexpr_exceptions >= 202502L
>-#define _GLIBCXX_CONSTEXPR_FORMAT_ERROR constexpr
>-#else
>-#define _GLIBCXX_CONSTEXPR_FORMAT_ERROR
>-#endif
>-
> // [format.error], class format_error
> class format_error : public runtime_error
> {
> public:
>- _GLIBCXX_CONSTEXPR_FORMAT_ERROR explicit format_error(const string& __what)
>+ _GLIBCXX_CONSTEXPR_FORMAT
>+ explicit format_error(const string& __what)
> : runtime_error(__what) { }
>- _GLIBCXX_CONSTEXPR_FORMAT_ERROR explicit format_error(const char* __what)
>+
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
>+ format_error(const char* __what)
> : runtime_error(__what) { }
> };
>
> /// @cond undocumented
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __throw_format_error(const char* __what)
> { _GLIBCXX_THROW_OR_ABORT(format_error(__what)); }
>
>-#undef _GLIBCXX_CONSTEXPR_FORMAT_ERROR
>-
> namespace __format
> {
> // XXX use named functions for each constexpr error?
>
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __unmatched_left_brace_in_format_string()
> { __throw_format_error("format error: unmatched '{' in format string"); }
>
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __unmatched_right_brace_in_format_string()
> { __throw_format_error("format error: unmatched '}' in format string"); }
>
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __conflicting_indexing_in_format_string()
> { __throw_format_error("format error: conflicting indexing style in format string"); }
>
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __invalid_arg_id_in_format_string()
> { __throw_format_error("format error: invalid arg-id in format string"); }
>
> [[noreturn]]
>- inline void
>+ inline _GLIBCXX_CONSTEXPR_FORMAT void
> __failed_to_parse_format_spec()
> { __throw_format_error("format error: failed to parse format-spec"); }
>
>@@ -517,7 +517,7 @@ namespace __format
> using enum _WidthPrec;
>
> template<typename _Context>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> __int_from_arg(const basic_format_arg<_Context>& __arg);
>
> constexpr bool __is_digit(char __c)
>@@ -750,7 +750,7 @@ namespace __format
> }
>
> template<typename _Context>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> _M_get_width(_Context& __ctx) const
> {
> size_t __width = 0;
>@@ -762,7 +762,7 @@ namespace __format
> }
>
> template<typename _Context>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> _M_get_precision(_Context& __ctx) const
> {
> size_t __prec = -1;
>@@ -775,7 +775,7 @@ namespace __format
> };
>
> template<typename _Int>
>- inline char*
>+ inline _GLIBCXX_CONSTEXPR_FORMAT char*
> __put_sign(_Int __i, _Sign __sign, char* __dest) noexcept
> {
> if (__i < 0)
>@@ -792,7 +792,7 @@ namespace __format
> // Write STR to OUT (and do so efficiently if OUT is a _Sink_iter).
> template<typename _Out, typename _CharT>
> requires output_iterator<_Out, const _CharT&>
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write(_Out __out, basic_string_view<_CharT> __str)
> {
> if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
>@@ -809,7 +809,7 @@ namespace __format
> // Write STR to OUT with NFILL copies of FILL_CHAR specified by ALIGN.
> // pre: __align != _Align_default
> template<typename _Out, typename _CharT>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_padded(_Out __out, basic_string_view<_CharT> __str,
> _Align __align, size_t __nfill, char32_t __fill_char)
> {
>@@ -883,7 +883,7 @@ namespace __format
> // Write STR to OUT, with alignment and padding as determined by SPEC.
> // pre: __spec._M_align != _Align_default || __align != _Align_default
> template<typename _CharT, typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_padded_as_spec(basic_string_view<type_identity_t<_CharT>> __str,
> size_t __estimated_width,
> basic_format_context<_Out, _CharT>& __fc,
>@@ -905,7 +905,7 @@ namespace __format
> }
>
> template<typename _CharT>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> __truncate(basic_string_view<_CharT>& __s, size_t __prec)
> {
> if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
>@@ -1049,7 +1049,7 @@ namespace __format
>
> using uint_least32_t = __UINT_LEAST32_TYPE__;
> template<typename _Out, typename _CharT>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escape_seq(_Out __out, uint_least32_t __val,
> basic_string_view<_CharT> __prefix)
> {
>@@ -1079,7 +1079,7 @@ namespace __format
> }
>
> template<typename _Out, typename _CharT>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escape_seqs(_Out __out, basic_string_view<_CharT> __units)
> {
> using _UChar = make_unsigned_t<_CharT>;
>@@ -1090,7 +1090,7 @@ namespace __format
> }
>
> template<typename _Out, typename _CharT>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escaped_char(_Out __out, _CharT __c)
> {
> using _UChar = make_unsigned_t<_CharT>;
>@@ -1146,7 +1146,7 @@ namespace __format
> }
>
> template<typename _CharT, typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escaped_unicode_part(_Out __out, basic_string_view<_CharT>& __str,
> bool& __prev_esc, _Term_char __term)
> {
>@@ -1224,7 +1224,7 @@ namespace __format
> }
>
> template<typename _CharT, typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escaped_unicode(_Out __out, basic_string_view<_CharT> __str,
> _Term_char __term)
> {
>@@ -1236,7 +1236,7 @@ namespace __format
> }
>
> template<typename _CharT, typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __write_escaped(_Out __out, basic_string_view<_CharT> __str, _Term_char __term)
> {
> __out = __format::__write(__out, _Escapes<_CharT>::_S_term(__term));
>@@ -1257,12 +1257,14 @@ namespace __format
> struct _Optional_locale
> {
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Optional_locale() : _M_dummy(), _M_hasval(false) { }
>
> _Optional_locale(const locale& __loc) noexcept
> : _M_loc(__loc), _M_hasval(true)
> { }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Optional_locale(const _Optional_locale& __l) noexcept
> : _M_dummy(), _M_hasval(__l._M_hasval)
> {
>@@ -1270,6 +1272,7 @@ namespace __format
> std::construct_at(&_M_loc, __l._M_loc);
> }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Optional_locale&
> operator=(const _Optional_locale& __l) noexcept
> {
>@@ -1291,6 +1294,7 @@ namespace __format
> return *this;
> }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> ~_Optional_locale() { if (_M_hasval) _M_loc.~locale(); }
>
> _Optional_locale&
>@@ -1317,7 +1321,8 @@ namespace __format
> return _M_loc;
> }
>
>- bool has_value() const noexcept { return _M_hasval; }
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
>+ has_value() const noexcept { return _M_hasval; }
>
> union {
> char _M_dummy = '\0';
>@@ -1391,7 +1396,7 @@ namespace __format
> }
>
> template<typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> format(basic_string_view<_CharT> __s,
> basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -1408,7 +1413,7 @@ namespace __format
> }
>
> template<typename _Out>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> _M_format_escaped(basic_string_view<_CharT> __s,
> basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -1433,7 +1438,7 @@ namespace __format
> #if __glibcxx_format_ranges // C++ >= 23 && HOSTED
> template<ranges::input_range _Rg, typename _Out>
> requires same_as<remove_cvref_t<ranges::range_reference_t<_Rg>>, _CharT>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> _M_format_range(_Rg&& __rg, basic_format_context<_Out, _CharT>& __fc) const
> {
> using _Range = remove_reference_t<_Rg>;
>@@ -1482,6 +1487,28 @@ namespace __format
> _Spec<_CharT> _M_spec{};
> };
>
>+ // A partial implementation of std::toupper that is constexpr-enabled,
>+ // sufficient for formatting purposes.
>+ [[__gnu__::__always_inline__]]
>+ constexpr char
>+ __toupper_numeric(char __c)
>+ {
>+ switch (__c)
>+ {
>+ case 'a': return 'A';
>+ case 'b': return 'B';
>+ case 'c': return 'C';
>+ case 'd': return 'D';
>+ case 'e': return 'E';
>+ case 'f': return 'F';
>+ case 'i': return 'I';
>+ case 'n': return 'N';
>+ case 'p': return 'P';
>+ case 'x': return 'X';
>+ default: return __c;
>+ }
>+ }
>+
> template<__char _CharT>
> struct __formatter_int
> {
>@@ -1641,6 +1668,7 @@ namespace __format
> }
>
> template<typename _Int, typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(_Int __i, basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -1690,11 +1718,7 @@ namespace __format
> __res = to_chars(__start, __end, __u, 16);
> if (_M_spec._M_type == _Pres_X)
> for (auto __p = __start; __p != __res.ptr; ++__p)
>-#if __has_builtin(__builtin_toupper)
>- *__p = __builtin_toupper(*__p);
>-#else
>- *__p = std::toupper(*__p);
>-#endif
>+ *__p = __format::__toupper_numeric(*__p);
> break;
> default:
> __builtin_unreachable();
>@@ -1703,8 +1727,7 @@ namespace __format
> if (_M_spec._M_alt && __base_prefix.size())
> {
> __start -= __base_prefix.size();
>- __builtin_memcpy(__start, __base_prefix.data(),
>- __base_prefix.size());
>+ ranges::copy(__base_prefix, __start);
I'm concerned about the impact on compilation speed of this change.
OK for trunk, but we might need to revisit this part.
> }
> __start = __format::__put_sign(__i, _M_spec._M_sign, __start - 1);
>
>@@ -1728,6 +1751,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(bool __i, basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -1758,6 +1782,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format_character(_CharT __c,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -1789,7 +1814,7 @@ namespace __format
> }
>
> template<typename _Int>
>- static _CharT
>+ static _GLIBCXX_CONSTEXPR_FORMAT _CharT
> _S_to_character(_Int __i)
> {
> using _Traits = __gnu_cxx::__int_traits<_CharT>;
>@@ -1810,6 +1835,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format_int(basic_string_view<_CharT> __str, size_t __prefix_len,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -2199,7 +2225,7 @@ namespace __format
> if (__upper)
> {
> for (char* __p = __start; __p != __res.ptr; ++__p)
>- *__p = std::toupper(*__p);
>+ *__p = __format::__toupper_numeric(*__p);
> }
>
> bool __have_sign = true;
>@@ -2512,10 +2538,13 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
> {
>- auto __u = reinterpret_cast<__UINTPTR_TYPE__>(__v);
>+ auto __u = __v
>+ ? reinterpret_cast<__UINTPTR_TYPE__>(__v)
>+ : static_cast<__UINTPTR_TYPE__>(0);
> return __formatter_int<_CharT>(_M_spec).format(__u, __fc);
> }
>
>@@ -2550,6 +2579,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(_CharT __u, basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -2588,6 +2618,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, wchar_t>::iterator
> format(char __u, basic_format_context<_Out, wchar_t>& __fc) const
> {
>@@ -2623,6 +2654,7 @@ namespace __format
>
> template<typename _Out>
> [[__gnu__::__nonnull__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(_CharT* __u, basic_format_context<_Out, _CharT>& __fc) const
> { return _M_f.format(__u, __fc); }
>@@ -2652,6 +2684,7 @@ namespace __format
>
> template<typename _Out>
> [[__gnu__::__nonnull__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(const _CharT* __u,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -2682,6 +2715,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(const _CharT (&__u)[_Nm],
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -2711,6 +2745,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, char>::iterator
> format(const basic_string<char, _Traits, _Alloc>& __u,
> basic_format_context<_Out, char>& __fc) const
>@@ -2743,6 +2778,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, wchar_t>::iterator
> format(const basic_string<wchar_t, _Traits, _Alloc>& __u,
> basic_format_context<_Out, wchar_t>& __fc) const
>@@ -2776,6 +2812,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, char>::iterator
> format(basic_string_view<char, _Traits> __u,
> basic_format_context<_Out, char>& __fc) const
>@@ -2808,6 +2845,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, wchar_t>::iterator
> format(basic_string_view<wchar_t, _Traits> __u,
> basic_format_context<_Out, wchar_t>& __fc) const
>@@ -2871,6 +2909,7 @@ namespace __format
> }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
> { return _M_f.format(__u, __fc); }
>@@ -3082,6 +3121,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
> { return _M_f.format(__v, __fc); }
>@@ -3107,6 +3147,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(void* __v, basic_format_context<_Out, _CharT>& __fc) const
> { return _M_f.format(__v, __fc); }
>@@ -3132,6 +3173,7 @@ namespace __format
> { return _M_f.parse(__pc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(nullptr_t, basic_format_context<_Out, _CharT>& __fc) const
> { return _M_f.format(nullptr, __fc); }
>@@ -3276,11 +3318,11 @@ namespace __format
> constexpr _Sink_iter
> operator++(int) { return *this; }
>
>- auto
>+ _GLIBCXX_CONSTEXPR_FORMAT auto
> _M_reserve(size_t __n) const
> { return _M_sink->_M_reserve(__n); }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_discarding() const
> { return _M_sink->_M_discarding(); }
> };
>@@ -3312,7 +3354,7 @@ namespace __format
>
> // The portion of the span that has been written to.
> [[__gnu__::__always_inline__]]
>- span<_CharT>
>+ _GLIBCXX_CONSTEXPR_FORMAT span<_CharT>
> _M_used() const noexcept
> { return _M_span.first(_M_next - _M_span.begin()); }
>
>@@ -3329,7 +3371,7 @@ namespace __format
> { _M_next = _M_span.begin(); }
>
> // Replace the current output range.
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_reset(span<_CharT> __s, size_t __pos = 0) noexcept
> {
> _M_span = __s;
>@@ -3369,11 +3411,14 @@ namespace __format
> struct _Reservation
> {
> // True if the reservation was successful, false otherwise.
>+ _GLIBCXX_CONSTEXPR_FORMAT
> explicit operator bool() const noexcept { return _M_sink; }
> // A pointer to write directly to the sink.
>- _CharT* get() const noexcept { return _M_sink->_M_next.operator->(); }
>+ _GLIBCXX_CONSTEXPR_FORMAT _CharT*
>+ get() const noexcept { return _M_sink->_M_next.operator->(); }
> // Add n to the _M_next iterator for the sink.
>- void _M_bump(size_t __n) { _M_sink->_M_bump(__n); }
>+ _GLIBCXX_CONSTEXPR_FORMAT void
>+ _M_bump(size_t __n) { _M_sink->_M_bump(__n); }
> _Sink* _M_sink;
> };
>
>@@ -3381,7 +3426,7 @@ namespace __format
> // If anything is written to the reservation then there must be a call
> // to _M_bump(N2) before any call to another member function of *this,
> // where N2 is the number of characters written.
>- virtual _Reservation
>+ _GLIBCXX_CONSTEXPR_FORMAT virtual _Reservation
> _M_reserve(size_t __n)
> {
> if (__n <= _M_unused().size())
>@@ -3398,12 +3443,12 @@ namespace __format
>
> // Update the next output position after writing directly to the sink.
> // pre: no calls to _M_write or _M_overflow since _M_reserve.
>- virtual void
>+ _GLIBCXX_CONSTEXPR_FORMAT virtual void
> _M_bump(size_t __n)
> { _M_next += __n; }
>
> // Returns true if the _Sink is discarding incoming characters.
>- virtual bool
>+ _GLIBCXX_CONSTEXPR_FORMAT virtual bool
> _M_discarding() const
> { return false; }
>
>@@ -3421,7 +3466,7 @@ namespace __format
> template<typename _CharT>
> class _Fixedbuf_sink final : public _Sink<_CharT>
> {
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> __glibcxx_assert(false);
>@@ -3469,7 +3514,7 @@ namespace __format
> _Seq _M_seq;
> protected:
> // Transfer buffer contents to the sequence, so buffer can be refilled.
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> auto __s = this->_M_used();
>@@ -3488,7 +3533,7 @@ namespace __format
> this->_M_rewind();
> }
>
>- typename _Sink<_CharT>::_Reservation
>+ _GLIBCXX_CONSTEXPR_FORMAT typename _Sink<_CharT>::_Reservation
> _M_reserve(size_t __n) override
> {
> // We might already have n characters available in this->_M_unused(),
>@@ -3524,7 +3569,7 @@ namespace __format
> return _Sink<_CharT>::_M_reserve(__n);
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_bump(size_t __n) override
> {
> if constexpr (__is_specialization_of<_Seq, basic_string>
>@@ -3539,7 +3584,8 @@ namespace __format
> }
> }
>
>- void _M_trim(span<const _CharT> __s)
>+ _GLIBCXX_CONSTEXPR_FORMAT void
>+ _M_trim(span<const _CharT> __s)
> requires __is_specialization_of<_Seq, basic_string>
> {
> _GLIBCXX_DEBUG_ASSERT(__s.data() == this->_M_buf
>@@ -3555,16 +3601,18 @@ namespace __format
> // to _M_buf if it overflows? Or even do that for all unused capacity?
>
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Seq_sink() noexcept(is_nothrow_default_constructible_v<_Seq>)
> { }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Seq_sink(_Seq&& __s) noexcept(is_nothrow_move_constructible_v<_Seq>)
> : _M_seq(std::move(__s))
> { }
>
> using _Sink<_CharT>::out;
>
>- _Seq
>+ _GLIBCXX_CONSTEXPR_FORMAT _Seq
> get() &&
> {
> if (this->_M_used().size() != 0)
>@@ -3574,7 +3622,7 @@ namespace __format
>
> // A writable span that views everything written to the sink.
> // Will be either a view over _M_seq or the used part of _M_buf.
>- span<_CharT>
>+ _GLIBCXX_CONSTEXPR_FORMAT span<_CharT>
> _M_span()
> {
> auto __s = this->_M_used();
>@@ -3587,7 +3635,7 @@ namespace __format
> return __s;
> }
>
>- basic_string_view<_CharT>
>+ _GLIBCXX_CONSTEXPR_FORMAT basic_string_view<_CharT>
> view()
> {
> auto __span = _M_span();
>@@ -3612,7 +3660,7 @@ namespace __format
> protected:
> size_t _M_count = 0;
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> auto __s = this->_M_used();
>@@ -3632,7 +3680,7 @@ namespace __format
> _M_count += __s.size();
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_discarding() const override
> {
> // format_to_n return total number of characters, that would be written,
>@@ -3642,14 +3690,14 @@ namespace __format
>
> public:
> [[__gnu__::__always_inline__]]
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __max = -1)
> : _M_out(std::move(__out)), _M_max(__max)
> { }
>
> using _Sink<_CharT>::out;
>
>- format_to_n_result<_OutIter>
>+ _GLIBCXX_CONSTEXPR_FORMAT format_to_n_result<_OutIter>
> _M_finish() &&
> {
> if (this->_M_used().size() != 0)
>@@ -3678,7 +3726,7 @@ namespace __format
> _CharT _M_buf[64]; // Write here after outputting _M_max characters.
>
> protected:
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> if (this->_M_unused().size() != 0)
>@@ -3702,7 +3750,7 @@ namespace __format
> }
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_discarding() const override
> {
> // format_to_n return total number of characters, that would be written,
>@@ -3710,7 +3758,7 @@ namespace __format
> return false;
> }
>
>- typename _Sink<_CharT>::_Reservation
>+ _GLIBCXX_CONSTEXPR_FORMAT typename _Sink<_CharT>::_Reservation
> _M_reserve(size_t __n) final
> {
> auto __avail = this->_M_unused();
>@@ -3727,7 +3775,7 @@ namespace __format
>
> private:
> template<typename _IterDifference>
>- static size_t
>+ static _GLIBCXX_CONSTEXPR_FORMAT size_t
> _S_trim_max(_IterDifference __max)
> {
> if (__max < 0)
>@@ -3740,7 +3788,7 @@ namespace __format
> }
>
> [[__gnu__::__always_inline__]]
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_rebuf(_CharT* __ptr, size_t __total, size_t __inuse = 0)
> {
> std::span<_CharT> __span(__ptr, __total);
>@@ -3748,7 +3796,7 @@ namespace __format
> }
>
> public:
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Ptr_sink(_CharT* __ptr, size_t __n = _S_no_limit) noexcept
> : _Sink<_CharT>(_M_buf), _M_max(__n)
> {
>@@ -3773,13 +3821,13 @@ namespace __format
> }
>
> template<contiguous_iterator _OutIter>
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Ptr_sink(_OutIter __out, iter_difference_t<_OutIter> __n = -1)
> : _Ptr_sink(std::to_address(__out), _S_trim_max(__n))
> { }
>
> template<contiguous_iterator _OutIter>
>- format_to_n_result<_OutIter>
>+ _GLIBCXX_CONSTEXPR_FORMAT format_to_n_result<_OutIter>
> _M_finish(_OutIter __first) const
> {
> auto __s = this->_M_used();
>@@ -3821,12 +3869,12 @@ namespace __format
> size_t _M_printwidth;
>
> [[__gnu__::__always_inline__]]
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_ignoring() const
> { return _M_printwidth >= _M_maxwidth; }
>
> [[__gnu__::__always_inline__]]
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_buffering() const
> {
> if (_M_printwidth < _M_padwidth)
>@@ -3836,7 +3884,7 @@ namespace __format
> return false;
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_sync_discarding()
> {
> if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
>@@ -3844,7 +3892,7 @@ namespace __format
> _M_maxwidth = _M_printwidth;
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_flush()
> {
> span<_CharT> __new = this->_M_used();
>@@ -3854,7 +3902,7 @@ namespace __format
> this->_M_rewind();
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_force_update()
> {
> auto __str = this->view();
>@@ -3882,7 +3930,7 @@ namespace __format
> return false;
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_update(size_t __new)
> {
> _M_printwidth += __new;
>@@ -3892,7 +3940,7 @@ namespace __format
> return true;
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> // Ignore characters in buffer, and override it.
>@@ -3907,11 +3955,11 @@ namespace __format
> _Str_sink<_CharT>::_M_overflow();
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_discarding() const override
> { return _M_ignoring(); }
>
>- typename _Sink<_CharT>::_Reservation
>+ _GLIBCXX_CONSTEXPR_FORMAT typename _Sink<_CharT>::_Reservation
> _M_reserve(size_t __n) override
> {
> // Ignore characters in buffer, if any.
>@@ -3930,7 +3978,7 @@ namespace __format
> return _Sink<_CharT>::_M_reserve(__n);
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_bump(size_t __n) override
> {
> // Ignore the written characters.
>@@ -3945,19 +3993,19 @@ namespace __format
>
> public:
> [[__gnu__::__always_inline__]]
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Padding_sink(_Out __out, size_t __padwidth, size_t __maxwidth)
> : _M_padwidth(__padwidth), _M_maxwidth(__maxwidth),
> _M_out(std::move(__out)), _M_printwidth(0)
> { _M_sync_discarding(); }
>
> [[__gnu__::__always_inline__]]
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Padding_sink(_Out __out, size_t __padwidth)
> : _Padding_sink(std::move(__out), __padwidth, (size_t)-1)
> { }
>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> _M_finish(_Align __align, char32_t __fill_char)
> {
> // Handle any characters in the buffer.
>@@ -3996,14 +4044,14 @@ namespace __format
> unsigned _M_prev_escape : 1;
> unsigned _M_out_discards : 1;
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_sync_discarding()
> {
> if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
> _M_out_discards = _M_out._M_discarding();
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_write()
> {
> span<_CharT> __bytes = this->_M_used();
>@@ -4029,7 +4077,7 @@ namespace __format
> _M_sync_discarding();
> }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_overflow() override
> {
> if (_M_out_discards)
>@@ -4038,13 +4086,13 @@ namespace __format
> _M_write();
> }
>
>- bool
>+ _GLIBCXX_CONSTEXPR_FORMAT bool
> _M_discarding() const override
> { return _M_out_discards; }
>
> public:
> [[__gnu__::__always_inline__]]
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> _Escaping_sink(_Out __out, _Term_char __term)
> : _M_out(std::move(__out)), _M_term(__term),
> _M_prev_escape(true), _M_out_discards(false)
>@@ -4053,7 +4101,7 @@ namespace __format
> _M_sync_discarding();
> }
>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> _M_finish()
> {
> if (_M_out_discards)
>@@ -4105,7 +4153,7 @@ namespace __format
> const _Tp, _Tp>;
>
> template<typename _Tq>
>- static void
>+ static _GLIBCXX_CONSTEXPR_FORMAT void
> _S_format(basic_format_parse_context<_CharT>& __parse_ctx,
> _Context& __format_ctx, const void* __ptr)
> {
>@@ -4118,7 +4166,7 @@ namespace __format
>
> template<typename _Tp>
> requires (!is_same_v<remove_cv_t<_Tp>, handle>)
>- explicit
>+ explicit _GLIBCXX_CONSTEXPR_FORMAT
> handle(_Tp& __val) noexcept
> : _M_ptr(__builtin_addressof(__val))
> , _M_func(&_S_format<__maybe_const_t<_Tp>>)
>@@ -4131,7 +4179,7 @@ namespace __format
> handle& operator=(const handle&) = default;
>
> [[__gnu__::__always_inline__]]
>- void
>+ void _GLIBCXX_CONSTEXPR_FORMAT
> format(basic_format_parse_context<_CharT>& __pc, _Context& __fc) const
> { _M_func(__pc, __fc, this->_M_ptr); }
>
>@@ -4183,10 +4231,12 @@ namespace __format
> };
>
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Arg_value() : _M_none() { }
>
> #if 0
> template<typename _Tp>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Arg_value(in_place_type_t<_Tp>, _Tp __val)
> { _S_get<_Tp>() = __val; }
> #endif
>@@ -4195,7 +4245,7 @@ namespace __format
> // Value of second argument (if provided), is assigned to that member.
> template<typename _Tp, typename _Self, typename... _Value>
> [[__gnu__::__always_inline__]]
>- static auto&
>+ static _GLIBCXX_CONSTEXPR_FORMAT auto&
> _S_access(_Self& __u, _Value... __value) noexcept
> {
> static_assert(sizeof...(_Value) <= 1);
>@@ -4259,23 +4309,24 @@ namespace __format
> else if constexpr (is_same_v<_Tp, handle>)
> return __u._M_handle;
> // Otherwise, ill-formed.
>+ __builtin_unreachable();
> }
>
> template<typename _Tp>
> [[__gnu__::__always_inline__]]
>- auto&
>+ _GLIBCXX_CONSTEXPR_FORMAT auto&
> _M_get() noexcept
> { return _S_access<_Tp>(*this); }
>
> template<typename _Tp>
> [[__gnu__::__always_inline__]]
>- const auto&
>+ _GLIBCXX_CONSTEXPR_FORMAT const auto&
> _M_get() const noexcept
> { return _S_access<_Tp>(*this); }
>
> template<typename _Tp>
> [[__gnu__::__always_inline__]]
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_set(_Tp __v) noexcept
> {
> // Explicitly construct types without trivial default constructor.
>@@ -4295,7 +4346,8 @@ namespace __format
> class _Arg_store;
>
> template<typename _Visitor, typename _Ctx>
>- decltype(auto) __visit_format_arg(_Visitor&&, basic_format_arg<_Ctx>);
>+ _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
>+ __visit_format_arg(_Visitor&&, basic_format_arg<_Ctx>);
>
> template<typename _Ch, typename _Tp>
> consteval _Arg_t
>@@ -4312,20 +4364,21 @@ namespace __format
> using handle = __format::_Arg_value<_Context>::handle;
>
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_arg() noexcept : _M_type(__format::_Arg_none) { }
>
> [[nodiscard,__gnu__::__always_inline__]]
>- explicit operator bool() const noexcept
>+ explicit _GLIBCXX_CONSTEXPR_FORMAT operator bool() const noexcept
> { return _M_type != __format::_Arg_none; }
>
> #if __cpp_lib_format >= 202306L // >= C++26
> template<typename _Visitor>
>- decltype(auto)
>+ _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> visit(this basic_format_arg __arg, _Visitor&& __vis)
> { return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type); }
>
> template<typename _Res, typename _Visitor>
>- _Res
>+ _GLIBCXX_CONSTEXPR_FORMAT _Res
> visit(this basic_format_arg __arg, _Visitor&& __vis)
> { return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type); }
> #endif
>@@ -4502,7 +4555,7 @@ namespace __format
> }
>
> template<typename _Tp>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_set(_Tp __v) noexcept
> {
> _M_type = _S_to_enum<_Tp>();
>@@ -4511,7 +4564,7 @@ namespace __format
>
> template<typename _Tp>
> requires __format::__formattable_with<_Tp, _Context>
>- explicit
>+ _GLIBCXX_CONSTEXPR_FORMAT explicit
> basic_format_arg(_Tp& __v) noexcept
> {
> using _Td = _Normalize<_Tp>;
>@@ -4525,15 +4578,15 @@ namespace __format
> }
>
> template<typename _Ctx, typename... _Argz>
>- friend auto
>+ friend _GLIBCXX_CONSTEXPR_FORMAT auto
> make_format_args(_Argz&...) noexcept;
>
> template<typename _Visitor, typename _Ctx>
>- friend decltype(auto)
>+ friend _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx>);
>
> template<typename _Visitor, typename _Ctx>
>- friend decltype(auto)
>+ friend _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> __format::__visit_format_arg(_Visitor&&, basic_format_arg<_Ctx>);
>
> template<typename _Ch, typename _Tp>
>@@ -4541,7 +4594,7 @@ namespace __format
> __format::__to_arg_t_enum() noexcept;
>
> template<typename _Visitor>
>- decltype(auto)
>+ _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> _M_visit(_Visitor&& __vis, __format::_Arg_t __type)
> {
> using namespace __format;
>@@ -4616,7 +4669,7 @@ namespace __format
> }
>
> template<typename _Visitor>
>- decltype(auto)
>+ _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> _M_visit_user(_Visitor&& __vis, __format::_Arg_t __type)
> {
> return _M_visit([&__vis]<typename _Tp>(_Tp& __val) -> decltype(auto)
>@@ -4640,7 +4693,7 @@ namespace __format
>
> template<typename _Visitor, typename _Context>
> _GLIBCXX26_DEPRECATED_SUGGEST("std::basic_format_arg::visit")
>- inline decltype(auto)
>+ inline _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg)
> {
> return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type);
>@@ -4650,7 +4703,7 @@ namespace __format
> namespace __format
> {
> template<typename _Visitor, typename _Ctx>
>- inline decltype(auto)
>+ inline _GLIBCXX_CONSTEXPR_FORMAT decltype(auto)
> __visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx> __arg)
> {
> return __arg._M_visit(std::forward<_Visitor>(__vis), __arg._M_type);
>@@ -4659,7 +4712,7 @@ namespace __format
> struct _WidthPrecVisitor
> {
> template<typename _Tp>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> operator()(_Tp& __arg) const
> {
> if constexpr (is_same_v<_Tp, monostate>)
>@@ -4685,7 +4738,7 @@ namespace __format
> #pragma GCC diagnostic push
> #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
> template<typename _Context>
>- inline size_t
>+ inline _GLIBCXX_CONSTEXPR_FORMAT size_t
> __int_from_arg(const basic_format_arg<_Context>& __arg)
> { return __format::__visit_format_arg(_WidthPrecVisitor(), __arg); }
>
>@@ -4733,11 +4786,11 @@ namespace __format
> const _Format_arg* _M_args; // Active when _M_packed_size == 0
> };
>
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> _M_size() const noexcept
> { return _M_packed_size ? _M_packed_size : _M_unpacked_size; }
>
>- typename __format::_Arg_t
>+ _GLIBCXX_CONSTEXPR_FORMAT typename __format::_Arg_t
> _M_type(size_t __i) const noexcept
> {
> uint64_t __t = _M_unpacked_size >> (__i * _S_packed_type_bits);
>@@ -4745,7 +4798,7 @@ namespace __format
> }
>
> template<typename _Ctx, typename... _Args>
>- friend auto
>+ friend _GLIBCXX_CONSTEXPR_FORMAT auto
> make_format_args(_Args&...) noexcept;
>
> // An array of _Arg_t enums corresponding to _Args...
>@@ -4756,10 +4809,11 @@ namespace __format
>
> public:
> template<typename... _Args>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_args(const _Store<_Args...>& __store) noexcept;
>
> [[nodiscard,__gnu__::__always_inline__]]
>- basic_format_arg<_Context>
>+ _GLIBCXX_CONSTEXPR_FORMAT basic_format_arg<_Context>
> get(size_t __i) const noexcept
> {
> basic_format_arg<_Context> __arg;
>@@ -4781,7 +4835,7 @@ namespace __format
> -> basic_format_args<_Context>;
>
> template<typename _Context, typename... _Args>
>- auto
>+ _GLIBCXX_CONSTEXPR_FORMAT auto
> make_format_args(_Args&... __fmt_args) noexcept;
>
> // An array of type-erased formatting arguments.
>@@ -4791,7 +4845,7 @@ namespace __format
> friend std::basic_format_args<_Context>;
>
> template<typename _Ctx, typename... _Argz>
>- friend auto std::
>+ friend _GLIBCXX_CONSTEXPR_FORMAT auto std::
> #if _GLIBCXX_INLINE_VERSION
> __8:: // Needed for PR c++/59256
> #endif
>@@ -4810,7 +4864,7 @@ namespace __format
> _Element_t _M_args[sizeof...(_Args)];
>
> template<typename _Tp>
>- static _Element_t
>+ static _GLIBCXX_CONSTEXPR_FORMAT _Element_t
> _S_make_elt(_Tp& __v)
> {
> using _Tq = remove_const_t<_Tp>;
>@@ -4836,6 +4890,7 @@ namespace __format
> template<typename... _Tp>
> requires (sizeof...(_Tp) == sizeof...(_Args))
> [[__gnu__::__always_inline__]]
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Arg_store(_Tp&... __a) noexcept
> : _M_args{_S_make_elt(__a)...}
> { }
>@@ -4847,7 +4902,7 @@ namespace __format
>
> template<typename _Context>
> template<typename... _Args>
>- inline
>+ inline _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_args<_Context>::
> basic_format_args(const _Store<_Args...>& __store) noexcept
> {
>@@ -4881,7 +4936,7 @@ namespace __format
> /// Capture formatting arguments for use by `std::vformat`.
> template<typename _Context = format_context, typename... _Args>
> [[nodiscard,__gnu__::__always_inline__]]
>- inline auto
>+ inline _GLIBCXX_CONSTEXPR_FORMAT auto
> make_format_args(_Args&... __fmt_args) noexcept
> {
> using _Fmt_arg = basic_format_arg<_Context>;
>@@ -4894,7 +4949,7 @@ namespace __format
> /// Capture formatting arguments for use by `std::vformat` (for wide output).
> template<typename... _Args>
> [[nodiscard,__gnu__::__always_inline__]]
>- inline auto
>+ inline _GLIBCXX_CONSTEXPR_FORMAT auto
> make_wformat_args(_Args&... __args) noexcept
> { return std::make_format_args<wformat_context>(__args...); }
> #endif
>@@ -4903,7 +4958,7 @@ namespace __format
> namespace __format
> {
> template<typename _Out, typename _CharT, typename _Context>
>- _Out
>+ _GLIBCXX_CONSTEXPR_FORMAT _Out
> __do_vformat_to(_Out, basic_string_view<_CharT>,
> const basic_format_args<_Context>&,
> const locale* = nullptr);
>@@ -4935,11 +4990,13 @@ namespace __format
> _Out _M_out;
> __format::_Optional_locale _M_loc;
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_context(basic_format_args<basic_format_context> __args,
> _Out __out)
> : _M_args(__args), _M_out(std::move(__out))
> { }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> basic_format_context(basic_format_args<basic_format_context> __args,
> _Out __out, const std::locale& __loc)
> : _M_args(__args), _M_out(std::move(__out)), _M_loc(__loc)
>@@ -4952,7 +5009,7 @@ namespace __format
> basic_format_context& operator=(const basic_format_context&) = delete;
>
> template<typename _Out2, typename _CharT2, typename _Context2>
>- friend _Out2
>+ friend _GLIBCXX_CONSTEXPR_FORMAT _Out2
> __format::__do_vformat_to(_Out2, basic_string_view<_CharT2>,
> const basic_format_args<_Context2>&,
> const locale*);
>@@ -4968,7 +5025,7 @@ namespace __format
> using formatter_type = formatter<_Tp, _CharT>;
>
> [[nodiscard]]
>- basic_format_arg<basic_format_context>
>+ _GLIBCXX_CONSTEXPR_FORMAT basic_format_arg<basic_format_context>
> arg(size_t __id) const noexcept
> { return _M_args.get(__id); }
>
>@@ -4976,9 +5033,11 @@ namespace __format
> std::locale locale() { return _M_loc.value(); }
>
> [[nodiscard]]
>- iterator out() { return std::move(_M_out); }
>+ _GLIBCXX_CONSTEXPR_FORMAT iterator
>+ out() { return std::move(_M_out); }
>
>- void advance_to(iterator __it) { _M_out = std::move(__it); }
>+ _GLIBCXX_CONSTEXPR_FORMAT void
>+ advance_to(iterator __it) { _M_out = std::move(__it); }
> };
>
>
>@@ -5117,6 +5176,7 @@ namespace __format
> class _Formatting_scanner : public _Scanner<_CharT>
> {
> public:
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Formatting_scanner(basic_format_context<_Out, _CharT>& __fc,
> basic_string_view<_CharT> __str)
> : _Scanner<_CharT>(__str), _M_fc(__fc)
>@@ -5224,7 +5284,7 @@ namespace __format
> };
>
> template<typename _CharT, unsigned = __unicode::__literal_encoding_is_unicode<_CharT>()>
>- _Sink_iter<_CharT>
>+ _GLIBCXX_CONSTEXPR_FORMAT _Sink_iter<_CharT>
> __do_vformat_to(_Sink_iter<_CharT> __out, basic_string_view<_CharT> __fmt,
> __format_context<_CharT>& __ctx)
> {
>@@ -5241,7 +5301,7 @@ namespace __format
> const char* __chars[] = { "false", "true" };
> if (auto __res = __out._M_reserve(__len))
> {
>- __builtin_memcpy(__res.get(), __chars[__arg], __len);
>+ ranges::copy_n(__chars[__arg], __len, __res.get());
> __res._M_bump(__len);
> __done = true;
> }
>@@ -5279,7 +5339,7 @@ namespace __format
> string_view __sv = __arg;
> if (auto __res = __out._M_reserve(__sv.size()))
> {
>- __builtin_memcpy(__res.get(), __sv.data(), __sv.size());
>+ ranges::copy(__sv, __res.get());
> __res._M_bump(__sv.size());
> __done = true;
> }
>@@ -5312,7 +5372,7 @@ namespace __format
> #endif
>
> template<typename _Out, typename _CharT, typename _Context>
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> __do_vformat_to(_Out __out, basic_string_view<_CharT> __fmt,
> const basic_format_args<_Context>& __args,
> const locale* __loc)
>@@ -5339,7 +5399,7 @@ namespace __format
> }
>
> template<typename _Out, typename _CharT>
>- inline format_to_n_result<_Out>
>+ inline _GLIBCXX_CONSTEXPR_FORMAT format_to_n_result<_Out>
> __do_vformat_to_n(_Out __out, iter_difference_t<_Out> __n,
> basic_string_view<_CharT> __fmt,
> const type_identity_t<
>@@ -5379,7 +5439,12 @@ namespace __format
> if constexpr (sizeof...(_Ts) != 0)
> {
> using _Parse_ctx = __format::_Scanner<_CharT>::_Parse_context;
>- auto __arg = static_cast<_Parse_ctx*>(this)->_M_types[__id];
>+ auto* __args = static_cast<_Parse_ctx*>(this)->_M_types;
>+ // Formatting scanner, no type check.
>+ if (!__args)
>+ return;
>+
>+ auto __arg = __args[__id];
> __format::_Arg_t __types[] = {
> __format::__to_arg_t_enum<_CharT, _Ts>()...
> };
>@@ -5397,7 +5462,7 @@ namespace __format
> requires convertible_to<const _Tp&, basic_string_view<_CharT>>
> consteval
> basic_format_string<_CharT, _Args...>::
>- basic_format_string(const _Tp& __s)
>+ basic_format_string(const _Tp& __s) noexcept
> : _M_str(__s)
> {
> __format::_Checking_scanner<_CharT, remove_cvref_t<_Args>...>
>@@ -5409,14 +5474,14 @@ namespace __format
>
> template<typename _Out> requires output_iterator<_Out, const char&>
> [[__gnu__::__always_inline__]]
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> vformat_to(_Out __out, string_view __fmt, format_args __args)
> { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
>
> #ifdef _GLIBCXX_USE_WCHAR_T
> template<typename _Out> requires output_iterator<_Out, const wchar_t&>
> [[__gnu__::__always_inline__]]
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> vformat_to(_Out __out, wstring_view __fmt, wformat_args __args)
> { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
> #endif
>@@ -5442,7 +5507,7 @@ namespace __format
> #endif
>
> [[nodiscard]]
>- inline string
>+ inline _GLIBCXX_CONSTEXPR_FORMAT string
> vformat(string_view __fmt, format_args __args)
> {
> __format::_Str_sink<char> __buf;
>@@ -5452,7 +5517,7 @@ namespace __format
>
> #ifdef _GLIBCXX_USE_WCHAR_T
> [[nodiscard]]
>- inline wstring
>+ inline _GLIBCXX_CONSTEXPR_FORMAT wstring
> vformat(wstring_view __fmt, wformat_args __args)
> {
> __format::_Str_sink<wchar_t> __buf;
>@@ -5483,14 +5548,14 @@ namespace __format
>
> template<typename... _Args>
> [[nodiscard]]
>- inline string
>+ inline _GLIBCXX_CONSTEXPR_FORMAT string
> format(format_string<_Args...> __fmt, _Args&&... __args)
> { return std::vformat(__fmt.get(), std::make_format_args(__args...)); }
>
> #ifdef _GLIBCXX_USE_WCHAR_T
> template<typename... _Args>
> [[nodiscard]]
>- inline wstring
>+ inline _GLIBCXX_CONSTEXPR_FORMAT wstring
> format(wformat_string<_Args...> __fmt, _Args&&... __args)
> { return std::vformat(__fmt.get(), std::make_wformat_args(__args...)); }
> #endif
>@@ -5519,7 +5584,7 @@ namespace __format
>
> template<typename _Out, typename... _Args>
> requires output_iterator<_Out, const char&>
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> format_to(_Out __out, format_string<_Args...> __fmt, _Args&&... __args)
> {
> return std::vformat_to(std::move(__out), __fmt.get(),
>@@ -5529,7 +5594,7 @@ namespace __format
> #ifdef _GLIBCXX_USE_WCHAR_T
> template<typename _Out, typename... _Args>
> requires output_iterator<_Out, const wchar_t&>
>- inline _Out
>+ inline _GLIBCXX_CONSTEXPR_FORMAT _Out
> format_to(_Out __out, wformat_string<_Args...> __fmt, _Args&&... __args)
> {
> return std::vformat_to(std::move(__out), __fmt.get(),
>@@ -5561,7 +5626,7 @@ namespace __format
>
> template<typename _Out, typename... _Args>
> requires output_iterator<_Out, const char&>
>- inline format_to_n_result<_Out>
>+ inline _GLIBCXX_CONSTEXPR_FORMAT format_to_n_result<_Out>
> format_to_n(_Out __out, iter_difference_t<_Out> __n,
> format_string<_Args...> __fmt, _Args&&... __args)
> {
>@@ -5573,7 +5638,7 @@ namespace __format
> #ifdef _GLIBCXX_USE_WCHAR_T
> template<typename _Out, typename... _Args>
> requires output_iterator<_Out, const wchar_t&>
>- inline format_to_n_result<_Out>
>+ inline _GLIBCXX_CONSTEXPR_FORMAT format_to_n_result<_Out>
> format_to_n(_Out __out, iter_difference_t<_Out> __n,
> wformat_string<_Args...> __fmt, _Args&&... __args)
> {
>@@ -5615,10 +5680,11 @@ namespace __format
> class _Counting_sink final : public _Ptr_sink<_CharT>
> {
> public:
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Counting_sink() : _Ptr_sink<_CharT>(nullptr, 0) { }
>
> [[__gnu__::__always_inline__]]
>- size_t
>+ _GLIBCXX_CONSTEXPR_FORMAT size_t
> count() const
> { return this->_M_count + this->_M_used().size(); }
> };
>@@ -5653,7 +5719,7 @@ namespace __format
>
> template<typename... _Args>
> [[nodiscard]]
>- inline size_t
>+ inline _GLIBCXX_CONSTEXPR_FORMAT size_t
> formatted_size(format_string<_Args...> __fmt, _Args&&... __args)
> {
> __format::_Counting_sink<char> __buf;
>@@ -5665,7 +5731,7 @@ namespace __format
> #ifdef _GLIBCXX_USE_WCHAR_T
> template<typename... _Args>
> [[nodiscard]]
>- inline size_t
>+ inline _GLIBCXX_CONSTEXPR_FORMAT size_t
> formatted_size(wformat_string<_Args...> __fmt, _Args&&... __args)
> {
> __format::_Counting_sink<wchar_t> __buf;
>@@ -5736,6 +5802,7 @@ namespace __format
> namespace __format
> {
> template<typename _CharT, typename _Out, typename _Callback>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> __format_padded(basic_format_context<_Out, _CharT>& __fc,
> const _Spec<_CharT>& __spec,
>@@ -5755,14 +5822,16 @@ namespace __format
>
> struct _Restore_out
> {
>+ _GLIBCXX_CONSTEXPR_FORMAT
> _Restore_out(basic_format_context<_Sink_iter<_CharT>, _CharT>& __fc)
> : _M_ctx(std::addressof(__fc)), _M_out(__fc.out())
> { }
>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_disarm()
> { _M_ctx = nullptr; }
>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> ~_Restore_out()
> {
> if (_M_ctx)
>@@ -5796,7 +5865,7 @@ namespace __format
> }
>
> template<typename _Out>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_format(__maybe_const<_Tp, _CharT>& __elem,
> basic_format_context<_Out, _CharT>& __fc,
> basic_string_view<_CharT> __sep) const
>@@ -5894,12 +5963,14 @@ namespace __format
>
> protected:
> template<typename _Tuple, typename _Out, size_t... _Ids>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format(_Tuple& __tuple, index_sequence<_Ids...>,
> basic_format_context<_Out, _CharT>& __fc) const
> { return _M_format_elems(std::get<_Ids>(__tuple)..., __fc); }
>
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format_elems(__maybe_const<_Tps, _CharT>&... __elems,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -5929,7 +6000,7 @@ namespace __format
> }
>
> template<typename _Out>
>- void
>+ _GLIBCXX_CONSTEXPR_FORMAT void
> _M_format(__maybe_const<_Tps, _CharT>&... __elems,
> basic_format_context<_Out, _CharT>& __fc,
> _String_view __sep) const
>@@ -5945,7 +6016,7 @@ namespace __format
> };
>
> template<size_t... _Ids>
>- static auto
>+ static _GLIBCXX_CONSTEXPR_FORMAT auto
> _S_create_storage(index_sequence<_Ids...>)
> -> __formatters_storage<_Ids...>;
> using _Formatters
>@@ -5981,6 +6052,7 @@ namespace __format
> // We deviate from standard, that declares this as template accepting
> // unconstrained FormatContext type, which seems unimplementable.
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(__maybe_const_pair& __p,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -6008,6 +6080,7 @@ namespace __format
> // We deviate from standard, that declares this as template accepting
> // unconstrained FormatContext type, which seems unimplementable.
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(__maybe_const_tuple& __t,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -6171,6 +6244,7 @@ namespace __format
> template<ranges::input_range _Rg, typename _Out>
> requires formattable<ranges::range_reference_t<_Rg>, _CharT> &&
> same_as<remove_cvref_t<ranges::range_reference_t<_Rg>>, _Tp>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(_Rg&& __rg, basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -6189,6 +6263,7 @@ namespace __format
>
> private:
> template<ranges::input_range _Rg, typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format(_Rg& __rg, basic_format_context<_Out, _CharT>& __fc) const
> {
>@@ -6206,6 +6281,7 @@ namespace __format
>
>
> template<ranges::input_range _Rg, typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> _M_format_elems(_Rg& __rg,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -6305,6 +6381,7 @@ namespace __format
> // We deviate from standard, that declares this as template accepting
> // unconstrained FormatContext type, which seems unimplementable.
> template<typename _Out>
>+ _GLIBCXX_CONSTEXPR_FORMAT
> typename basic_format_context<_Out, _CharT>::iterator
> format(__format::__maybe_const_range<_Rg, _CharT>& __rg,
> basic_format_context<_Out, _CharT>& __fc) const
>@@ -6331,6 +6408,7 @@ namespace __format
>
> #endif // C++23 formatting ranges
> #undef _GLIBCXX_WIDEN
>+#undef _GLIBCXX_CONSTEXPR_FORMAT
>
> _GLIBCXX_END_NAMESPACE_VERSION
> } // namespace std
>diff --git a/libstdc++-v3/testsuite/std/format/arguments/args_neg.cc b/libstdc++-v3/testsuite/std/format/arguments/args_neg.cc
>index 83c7b22d081..6894d6c4fc3 100644
>--- a/libstdc++-v3/testsuite/std/format/arguments/args_neg.cc
>+++ b/libstdc++-v3/testsuite/std/format/arguments/args_neg.cc
>@@ -15,7 +15,7 @@ void test_missing_specialization()
> {
> struct X { };
> X x;
>- (void)std::make_format_args(x); // { dg-error "here" }
>+ (void)std::make_format_args(x); // { dg-error "(here|in 'constexpr' expansion of)" }
> // { dg-error "std::formatter must be specialized" "" { target *-*-* } 0 }
> }
>
>@@ -37,7 +37,7 @@ void test(std::formatter<Y>& f, std::format_parse_context& pc) {
> void test_const_arg()
> {
> const Y y;
>- (void)std::make_format_args(y); // { dg-error "here" }
>+ (void)std::make_format_args(y); // { dg-error "(here|in 'constexpr' expansion of)" }
> // { dg-error "format arg must be non-const" "" { target *-*-* } 0 }
> }
>
>diff --git a/libstdc++-v3/testsuite/std/format/constexpr.cc b/libstdc++-v3/testsuite/std/format/constexpr.cc
>new file mode 100644
>index 00000000000..7f806081f4e
>--- /dev/null
>+++ b/libstdc++-v3/testsuite/std/format/constexpr.cc
>@@ -0,0 +1,166 @@
>+// { dg-do compile { target c++26 } }
>+
>+#include <format>
>+#include <string>
>+#include <string_view>
>+#include <tuple>
>+#include <vector>
>+#include <testsuite_hooks.h>
>+
>+#if _GLIBCXX_USE_CXX11_ABI
>+
>+#ifndef __glibcxx_constexpr_format
>+# error "Feature test macro for constexpr std::format is missing in <format>"
>+#elif __glibcxx_constexpr_format < 202511L
>+# error "Feature test macro for constexpr std::format has wrong value in <format>"
>+#endif
>+
>+// Slightly more general from __format::_Widen, works with character literals.
>+template<typename CharT>
>+consteval auto widen(auto narrow, auto wide)
>+{
>+ if constexpr (std::is_same_v<CharT, wchar_t>)
>+ return wide;
>+ else
>+ return narrow;
>+}
>+
>+#define WIDEN_(C, S) widen<C>(S, L##S)
>+#define WIDEN(S) WIDEN_(CharT, S)
>+
>+template<typename CharT>
>+constexpr void
>+test_format()
>+{
>+ using namespace std;
>+
>+ basic_string<CharT> res;
>+
>+ res = format(WIDEN("{}"), WIDEN('c'));
>+ VERIFY( res == WIDEN("c") );
>+ res = format(WIDEN("{1} {0} {0}"), WIDEN('a'), WIDEN('b'));
>+ VERIFY( res == WIDEN("b a a") );
>+ res = format(WIDEN("{:?}"), WIDEN('\n'));
>+ VERIFY( res == WIDEN("'\\n'") );
>+ res = format(WIDEN("{:.^10}"), WIDEN("hello"));
>+ VERIFY( res == WIDEN("..hello...") );
>+ res = format(WIDEN("{:.>{}}"), WIDEN("world"), 8);
>+ VERIFY( res == WIDEN("...world") );
>+ res = format(WIDEN("{:+#06X}"), 0xa);
>+ VERIFY( res == WIDEN("+0X00A") );
>+ res = format(WIDEN("{:p}"), nullptr);
>+ VERIFY( res == WIDEN("0x0") );
>+ res = format(WIDEN("{:07P}"), nullptr);
>+ VERIFY( res == WIDEN("0X00000") );
>+ res = format(WIDEN("{} {}"), true, false);
>+ VERIFY( res == WIDEN("true false") );
>+ res = format(WIDEN("{:+#06b}"), true);
>+ VERIFY( res == WIDEN("+0b001") );
>+ res = format(WIDEN("{} {} {}"), WIDEN("abc"), basic_string_view<CharT>(WIDEN("def")), basic_string<CharT>(WIDEN("ghi")));
>+ VERIFY( res == WIDEN("abc def ghi") );
>+ res = format(WIDEN("{:?}"), WIDEN("hello\nworld"));
>+ VERIFY( res == WIDEN("\"hello\\nworld\"") );
>+ res = format(WIDEN("{}"), tuple(1, true));
>+ VERIFY( res == WIDEN("(1, true)") );
>+ res = format(WIDEN("{:t<12m}"), tuple(WIDEN('a'), WIDEN("bc")));
>+ VERIFY( res == WIDEN("'a': \"bc\"ttt") );
>+ res = format(WIDEN("{:n}"), tuple(nullptr, -1, 1));
>+ VERIFY( res == WIDEN("0x0, -1, 1") );
>+ res = format(WIDEN("{}"), vector{1, 2, 3, 4});
>+ VERIFY( res == WIDEN("[1, 2, 3, 4]") );
>+ res = format(WIDEN("{:?s}"), vector{WIDEN('a'), WIDEN('\n'), WIDEN('b')});
>+ VERIFY( res == WIDEN("\"a\\nb\"") );
>+ res = format(WIDEN("{:n:+}"), vector{1, 2, 3});
>+ VERIFY( res == WIDEN("+1, +2, +3") );
>+}
>+
>+template<typename CharT>
>+constexpr void
>+test_format_to()
>+{
>+ using namespace std;
>+
>+ CharT buf[100];
>+ CharT* out;
>+
>+ out = format_to(buf, WIDEN("{:.^5}"), WIDEN("foo"));
>+ VERIFY( basic_string_view<CharT>(buf, out) == WIDEN(".foo.") );
>+ out = format_to(buf, WIDEN("{} {}"), nullptr, true);
>+ VERIFY( basic_string_view<CharT>(buf, out) == WIDEN("0x0 true") );
>+}
>+
>+template<typename CharT>
>+constexpr void
>+test_vformat()
>+{
>+ using namespace std;
>+ using context = __format::__format_context<CharT>;
>+
>+ basic_string<CharT> res;
>+
>+ int arg1 = 1;
>+ CharT arg2 = WIDEN('a');
>+ bool arg3 = true;
>+ res = vformat(WIDEN("{} {:?} {}"), make_format_args<context>(arg1, arg2, arg3));
>+ VERIFY( res == WIDEN("1 'a' true") );
>+}
>+
>+template<typename CharT>
>+constexpr void
>+test_vformat_to()
>+{
>+ using namespace std;
>+ using context = __format::__format_context<CharT>;
>+
>+ CharT buf[100];
>+ CharT* out;
>+
>+ nullptr_t arg1 = nullptr;
>+ basic_string<CharT> arg2 = WIDEN("foo");
>+ tuple<int, int> arg3{-3, 5};
>+ out = vformat_to(buf, WIDEN("{} {:?} {}"), make_format_args<context>(arg1, arg2, arg3));
>+ VERIFY( basic_string_view<CharT>(buf, out) == WIDEN("0x0 \"foo\" (-3, 5)") );
>+}
>+
>+template<typename CharT>
>+constexpr void
>+test_format_to_n()
>+{
>+ using namespace std;
>+
>+ CharT buf[100];
>+ format_to_n_result<CharT*> out;
>+ int n;
>+
>+ n = 100;
>+ out = format_to_n(buf, n, WIDEN("{:+} {:?} {}"), 1, WIDEN("\n\n"), vector{1, 2, 3});
>+ VERIFY( out.size <= n );
>+ VERIFY( out.out - buf == out.size );
>+ VERIFY( basic_string_view<CharT>(buf, out.size) == WIDEN("+1 \"\\n\\n\" [1, 2, 3]") );
>+ n = 12;
>+ out = format_to_n(buf, n, WIDEN("{} {} {}"), true, nullptr, WIDEN("long string"));
>+ VERIFY( out.size > n );
>+ VERIFY( out.out - buf == n );
>+ VERIFY( basic_string_view<CharT>(buf, out.out) == WIDEN("true 0x0 lon") );
>+}
>+
>+constexpr bool
>+all_tests()
>+{
>+ test_format<char>();
>+ test_format<wchar_t>();
>+ test_format_to<char>();
>+ test_format_to<wchar_t>();
>+ test_vformat<char>();
>+ test_vformat<wchar_t>();
>+ test_vformat_to<char>();
>+ test_vformat_to<wchar_t>();
>+ test_format_to_n<char>();
>+ test_format_to_n<wchar_t>();
>+
>+ return true;
>+}
>+
>+static_assert(all_tests());
>+
>+#endif // _GLIBCXX_USE_CXX11_ABI
>diff --git a/libstdc++-v3/testsuite/std/format/debug.cc b/libstdc++-v3/testsuite/std/format/debug.cc
>index 43e930c579e..01bb9074ba7 100644
>--- a/libstdc++-v3/testsuite/std/format/debug.cc
>+++ b/libstdc++-v3/testsuite/std/format/debug.cc
>@@ -1,5 +1,5 @@
>-// { dg-options "-fexec-charset=UTF-8 -fwide-exec-charset=UTF-32LE -DUNICODE_ENC" { target le } }
>-// { dg-options "-fexec-charset=UTF-8 -fwide-exec-charset=UTF-32BE -DUNICODE_ENC" { target be } }
>+// { dg-options "-fexec-charset=UTF-8 -fwide-exec-charset=UTF-32LE -DUNICODE_ENC -fconstexpr-ops-limit=500000000" { target le } }
>+// { dg-options "-fexec-charset=UTF-8 -fwide-exec-charset=UTF-32BE -DUNICODE_ENC -fconstexpr-ops-limit=500000000" { target be } }
> // { dg-do run { target c++23 } }
> // { dg-require-effective-target 4byte_wchar_t }
> // { dg-add-options no_pch }
>@@ -8,19 +8,25 @@
> #include <format>
> #include <testsuite_hooks.h>
>
>-std::string
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
>+CONSTEXPR std::string
> fdebug(char t)
> { return std::format("{:?}", t); }
>
>-std::wstring
>+CONSTEXPR std::wstring
> fdebug(wchar_t t)
> { return std::format(L"{:?}", t); }
>
>-std::string
>+CONSTEXPR std::string
> fdebug(std::string_view t)
> { return std::format("{:?}", t); }
>
>-std::wstring
>+CONSTEXPR std::wstring
> fdebug(std::wstring_view t)
> { return std::format(L"{:?}", t); }
>
>@@ -29,7 +35,7 @@ fdebug(std::wstring_view t)
> #define WIDEN(S) WIDEN_(CharT, S)
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_basic_escapes()
> {
> std::basic_string<CharT> res;
>@@ -72,7 +78,7 @@ test_basic_escapes()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_ascii_escapes()
> {
> std::basic_string<CharT> res;
>@@ -89,7 +95,7 @@ test_ascii_escapes()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_extended_ascii()
> {
> std::basic_string<CharT> res;
>@@ -117,7 +123,7 @@ test_extended_ascii()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_unicode_escapes()
> {
> #if UNICODE_ENC
>@@ -166,7 +172,7 @@ test_unicode_escapes()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_grapheme_extend()
> {
> #if UNICODE_ENC
>@@ -192,7 +198,7 @@ test_grapheme_extend()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_replacement_char()
> {
> #if UNICODE_ENC
>@@ -206,7 +212,7 @@ test_replacement_char()
> #endif // UNICODE_ENC
> }
>
>-void
>+CONSTEXPR void
> test_ill_formed_utf8_seq()
> {
> #if UNICODE_ENC
>@@ -244,7 +250,7 @@ test_ill_formed_utf8_seq()
> #endif // UNICODE_ENC
> }
>
>-void
>+CONSTEXPR void
> test_ill_formed_utf32()
> {
> #if UNICODE_ENC
>@@ -269,7 +275,7 @@ test_ill_formed_utf32()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_fill()
> {
> std::basic_string<CharT> res;
>@@ -315,7 +321,7 @@ test_fill()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_prec()
> {
> std::basic_string<CharT> res;
>@@ -341,7 +347,8 @@ test_prec()
> #endif // UNICODE_ENC
> }
>
>-bool strip_quote(std::string_view& v)
>+CONSTEXPR bool
>+strip_quote(std::string_view& v)
> {
> if (!v.starts_with('"'))
> return false;
>@@ -349,7 +356,8 @@ bool strip_quote(std::string_view& v)
> return true;
> }
>
>-bool strip_quotes(std::string_view& v)
>+CONSTEXPR bool
>+strip_quotes(std::string_view& v)
> {
> if (!v.starts_with('"') || !v.ends_with('"'))
> return false;
>@@ -358,7 +366,8 @@ bool strip_quotes(std::string_view& v)
> return true;
> }
>
>-bool strip_prefix(std::string_view& v, size_t n, char c)
>+CONSTEXPR bool
>+strip_prefix(std::string_view& v, size_t n, char c)
> {
> size_t pos = v.find_first_not_of(c);
> if (pos == std::string_view::npos)
>@@ -369,7 +378,8 @@ bool strip_prefix(std::string_view& v, size_t n, char c)
> return true;
> }
>
>-void test_padding()
>+CONSTEXPR void
>+test_padding()
> {
> std::string res;
> std::string_view resv;
>@@ -719,7 +729,8 @@ void test_padding()
> #endif // UNICODE_ENC
> }
>
>-void test_char_as_wchar()
>+CONSTEXPR void
>+test_char_as_wchar()
> {
> std::wstring res;
>
>@@ -751,8 +762,9 @@ struct std::formatter<DebugWrapper<T>, CharT>
> }
>
> template<typename Out>
>- Out format(DebugWrapper<T> const& t,
>- std::basic_format_context<Out, CharT>& fc) const
>+ CONSTEXPR Out
>+ format(DebugWrapper<T> const& t,
>+ std::basic_format_context<Out, CharT>& fc) const
> { return under.format(t.val, fc); }
>
> private:
>@@ -760,7 +772,7 @@ private:
> };
>
> template<typename CharT, typename StrT>
>-void
>+CONSTEXPR void
> test_formatter_str()
> {
> CharT buf[]{ 'a', 'b', 'c', 0 };
>@@ -770,7 +782,7 @@ test_formatter_str()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_formatter_arr()
> {
> std::basic_string<CharT> res;
>@@ -786,7 +798,7 @@ test_formatter_arr()
> }
>
> template<typename CharT, typename SrcT>
>-void
>+CONSTEXPR void
> test_formatter_char()
> {
> DebugWrapper<SrcT> in{ 'a' };
>@@ -795,7 +807,7 @@ test_formatter_char()
> }
>
> template<typename CharT>
>-void
>+CONSTEXPR void
> test_formatters()
> {
> test_formatter_char<CharT, CharT>();
>@@ -806,7 +818,7 @@ test_formatters()
> test_formatter_arr<CharT>();
> }
>
>-void
>+CONSTEXPR void
> test_formatters_c()
> {
> test_formatters<char>();
>@@ -814,7 +826,8 @@ test_formatters_c()
> test_formatter_char<wchar_t, char>();
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_basic_escapes<char>();
> test_basic_escapes<wchar_t>();
>@@ -840,4 +853,16 @@ int main()
> test_padding();
>
> test_formatters_c();
>+
>+ return true;
>+}
>+
>+#if defined(__glibcxx_constexpr_format) && defined(UNICODE_ENC)
>+// Deboug ouput is supported only for unicode literal encoding
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/dynamic_format.cc b/libstdc++-v3/testsuite/std/format/dynamic_format.cc
>index fde2555ccb2..aa3109cca4e 100644
>--- a/libstdc++-v3/testsuite/std/format/dynamic_format.cc
>+++ b/libstdc++-v3/testsuite/std/format/dynamic_format.cc
>@@ -3,7 +3,13 @@
> #include <format>
> #include <testsuite_hooks.h>
>
>-void
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
>+CONSTEXPR void
> test_char()
> {
> std::string fmt = "{}";
>@@ -11,7 +17,7 @@ test_char()
> VERIFY( s == "123" );
> }
>
>-void
>+CONSTEXPR void
> test_wchar()
> {
> std::wstring fmt = L"{:#o}";
>@@ -19,7 +25,7 @@ test_wchar()
> VERIFY( s == L"0710" );
> }
>
>-void
>+CONSTEXPR void
> test_internal_api()
> {
> // Using _Dynamic_format_string directly works even in C++20 mode.
>@@ -40,9 +46,20 @@ static_assert( !std::is_constructible_v<std::format_string<>,
> static_assert( !std::is_constructible_v<std::wformat_string<>,
> decltype(std::dynamic_format(L""))&&> );
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_char();
> test_wchar();
> test_internal_api();
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/functions/format.cc b/libstdc++-v3/testsuite/std/format/functions/format.cc
>index d342114083e..88e95a788b5 100644
>--- a/libstdc++-v3/testsuite/std/format/functions/format.cc
>+++ b/libstdc++-v3/testsuite/std/format/functions/format.cc
>@@ -5,6 +5,12 @@
>
> #include <format>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> #ifndef __cpp_lib_format
> # error "Feature test macro for std::format is missing in <format>"
> #elif __cpp_lib_format < 202110L
>@@ -41,7 +47,7 @@
> #include <cstdio>
> #include <testsuite_hooks.h>
>
>-void
>+CONSTEXPR void
> test_no_args()
> {
> std::string s;
>@@ -55,7 +61,7 @@ test_no_args()
> VERIFY( s == "128bpm }" );
> }
>
>-void
>+CONSTEXPR void
> test_unescaped()
> {
> #ifdef __cpp_exceptions
>@@ -78,7 +84,7 @@ struct brit_punc : std::numpunct<char>
> std::string do_falsename() const override { return "nah bruv"; }
> };
>
>-void
>+CONSTEXPR void
> test_std_examples()
> {
> using namespace std;
>@@ -125,10 +131,13 @@ test_std_examples()
> VERIFY(s0 == "1,+1,1, 1");
> string s1 = format("{0:},{0:+},{0:-},{0: }", -1);
> VERIFY(s1 == "-1,-1,-1,-1");
>- string s2 = format("{0:},{0:+},{0:-},{0: }", inf);
>- VERIFY(s2 == "inf,+inf,inf, inf");
>- string s3 = format("{0:},{0:+},{0:-},{0: }", nan);
>- VERIFY(s3 == "nan,+nan,nan, nan");
>+ if (!std::is_constant_evaluated())
>+ {
>+ string s2 = format("{0:},{0:+},{0:-},{0: }", inf);
>+ VERIFY(s2 == "inf,+inf,inf, inf");
>+ string s3 = format("{0:},{0:+},{0:-},{0: }", nan);
>+ VERIFY(s3 == "nan,+nan,nan, nan");
>+ }
> }
>
> // alternate form and zero fill
>@@ -143,34 +152,35 @@ test_std_examples()
> }
>
> // integer presentation types
>- {
>- // Change global locale so "{:L}" adds digit separators.
>- std::locale::global(std::locale({}, new brit_punc));
>-
>- string s0 = format("{}", 42);
>- VERIFY(s0 == "42");
>- string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);
>- VERIFY(s1 == "101010 42 52 2a");
>- string s2 = format("{0:#x} {0:#X}", 42);
>- VERIFY(s2 == "0x2a 0X2A");
>- string s3 = format("{:L}", 1234);
>- VERIFY(s3 == "1,234");
>-
>- // Test locale's "byte-and-a-half" grouping (Imperial word? tribble?).
>- string s4 = format("{:#Lx}", 0xfffff);
>- VERIFY(s4 == "0xff,fff");
>-
>- // Restore
>- std::locale::global(std::locale::classic());
>-
>- string s5 = format("{}", -100); // PR libstdc++/114325
>- VERIFY(s5 == "-100");
>- string s6 = format("{:d} {:d}", -123, 999);
>- VERIFY(s6 == "-123 999");
>- }
>+ if (!std::is_constant_evaluated())
>+ {
>+ // Change global locale so "{:L}" adds digit separators.
>+ std::locale::global(std::locale({}, new brit_punc));
>+
>+ string s0 = format("{}", 42);
>+ VERIFY(s0 == "42");
>+ string s1 = format("{0:b} {0:d} {0:o} {0:x}", 42);
>+ VERIFY(s1 == "101010 42 52 2a");
>+ string s2 = format("{0:#x} {0:#X}", 42);
>+ VERIFY(s2 == "0x2a 0X2A");
>+ string s3 = format("{:L}", 1234);
>+ VERIFY(s3 == "1,234");
>+
>+ // Test locale's "byte-and-a-half" grouping (Imperial word? tribble?).
>+ string s4 = format("{:#Lx}", 0xfffff);
>+ VERIFY(s4 == "0xff,fff");
>+
>+ // Restore
>+ std::locale::global(std::locale::classic());
>+
>+ string s5 = format("{}", -100); // PR libstdc++/114325
>+ VERIFY(s5 == "-100");
>+ string s6 = format("{:d} {:d}", -123, 999);
>+ VERIFY(s6 == "-123 999");
>+ }
> }
>
>-void
>+CONSTEXPR void
> test_alternate_forms()
> {
> std::string s;
>@@ -180,23 +190,26 @@ test_alternate_forms()
> s = std::format("{0:#b} {0:+#B} {0:#o} {0:#x} {0:+#X} {0: #d}", 0);
> VERIFY( s == "0b0 +0B0 0 0x0 +0X0 0" );
>
>- s = std::format("{0:+#012g} {0:+#014g} {0:+#014g}", 1234.0);
>- VERIFY( s == "+00001234.00 +0000001234.00 +0000001234.00" );
>- s = std::format("{0:+#0{1}g} {0:+#0{2}g} {0:+#0{2}g}", 1234.5, 12, 14);
>- VERIFY( s == "+00001234.50 +0000001234.50 +0000001234.50" );
>-
>- s = std::format("{:#.2g}", -0.0);
>- VERIFY( s == "-0.0" );
>-
>- // PR libstdc++/108046
>- s = std::format("{0:#.0} {0:#.1} {0:#.0g}", 10.0);
>- VERIFY( s == "1.e+01 1.e+01 1.e+01" );
>-
>- // PR libstdc++/113512
>- s = std::format("{:#.3g}", 0.025);
>- VERIFY( s == "0.0250" );
>- s = std::format("{:#07.3g}", 0.02);
>- VERIFY( s == "00.0200" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ s = std::format("{0:+#012g} {0:+#014g} {0:+#014g}", 1234.0);
>+ VERIFY( s == "+00001234.00 +0000001234.00 +0000001234.00" );
>+ s = std::format("{0:+#0{1}g} {0:+#0{2}g} {0:+#0{2}g}", 1234.5, 12, 14);
>+ VERIFY( s == "+00001234.50 +0000001234.50 +0000001234.50" );
>+
>+ s = std::format("{:#.2g}", -0.0);
>+ VERIFY( s == "-0.0" );
>+
>+ // PR libstdc++/108046
>+ s = std::format("{0:#.0} {0:#.1} {0:#.0g}", 10.0);
>+ VERIFY( s == "1.e+01 1.e+01 1.e+01" );
>+
>+ // PR libstdc++/113512
>+ s = std::format("{:#.3g}", 0.025);
>+ VERIFY( s == "0.0250" );
>+ s = std::format("{:#07.3g}", 0.02);
>+ VERIFY( s == "00.0200" );
>+ }
> }
>
> void
>@@ -275,7 +288,7 @@ test_locale()
> std::locale::global(cloc);
> }
>
>-void
>+CONSTEXPR void
> test_width()
> {
> std::string s;
>@@ -317,7 +330,7 @@ test_width()
> }
> }
>
>-void
>+CONSTEXPR void
> test_char()
> {
> std::string s;
>@@ -347,7 +360,7 @@ test_char()
> VERIFY( s == "11110000 11110000 240 360 f0 F0" );
> }
>
>-void
>+CONSTEXPR void
> test_wchar()
> {
> using namespace std::literals;
>@@ -356,24 +369,27 @@ test_wchar()
> s = std::format(L"{}", L'a');
> VERIFY( s == L"a" );
>
>- s = std::format(L"{} {} {} {} {} {}", L'0', 1, 2LL, 3.4, L"five", L"six"s);
>- VERIFY( s == L"0 1 2 3.4 five six" );
>-
>- std::locale loc;
>- s = std::format(loc, L"{:L} {:.3s}{:Lc}", true, L"data"sv, '.');
>- VERIFY( s == L"true dat." );
>-
>- s = std::format(L"{}", 0.0625);
>- VERIFY( s == L"0.0625" );
>- s = std::format(L"{}", 0.25);
>- VERIFY( s == L"0.25" );
>- s = std::format(L"{:+a} {:A}", 0x1.23p45, -0x1.abcdefp-15);
>- VERIFY( s == L"+1.23p+45 -1.ABCDEFP-15" );
>-
>- double inf = std::numeric_limits<double>::infinity();
>- double nan = std::numeric_limits<double>::quiet_NaN();
>- s = std::format(L"{0} {0:F} {1} {1:E}", -inf, -nan);
>- VERIFY( s == L"-inf -INF -nan -NAN" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ s = std::format(L"{} {} {} {} {} {}", L'0', 1, 2LL, 3.4, L"five", L"six"s);
>+ VERIFY( s == L"0 1 2 3.4 five six" );
>+
>+ std::locale loc;
>+ s = std::format(loc, L"{:L} {:.3s}{:Lc}", true, L"data"sv, '.');
>+ VERIFY( s == L"true dat." );
>+
>+ s = std::format(L"{}", 0.0625);
>+ VERIFY( s == L"0.0625" );
>+ s = std::format(L"{}", 0.25);
>+ VERIFY( s == L"0.25" );
>+ s = std::format(L"{:+a} {:A}", 0x1.23p45, -0x1.abcdefp-15);
>+ VERIFY( s == L"+1.23p+45 -1.ABCDEFP-15" );
>+
>+ double inf = std::numeric_limits<double>::infinity();
>+ double nan = std::numeric_limits<double>::quiet_NaN();
>+ s = std::format(L"{0} {0:F} {1} {1:E}", -inf, -nan);
>+ VERIFY( s == L"-inf -INF -nan -NAN" );
>+ }
>
> s = std::format(L"{0:#b} {0:#B} {0:#x} {0:#X}", 99);
> VERIFY( s == L"0b1100011 0B1100011 0x63 0X63" );
>@@ -382,20 +398,23 @@ test_wchar()
> s = std::format(L"{:d} {:d}", wchar_t(-1), char(-1));
> VERIFY( s.find('-') == std::wstring::npos );
>
>- auto ws = std::format(L"{:L}", 0.5);
>- VERIFY( ws == L"0.5" );
>- // The default C locale.
>- std::locale cloc = std::locale::classic();
>- // PR libstdc++/119671 use-after-free formatting floating-point to wstring
>- ws = std::format(cloc, L"{:L}", 0.5);
>- VERIFY( ws == L"0.5" );
>- // A locale with no name, but with the same facets as the C locale.
>- std::locale locx(cloc, &std::use_facet<std::ctype<char>>(cloc));
>- ws = std::format(locx, L"{:L}", 0.5);
>- VERIFY( ws == L"0.5" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ auto ws = std::format(L"{:L}", 0.5);
>+ VERIFY( ws == L"0.5" );
>+ // The default C locale.
>+ std::locale cloc = std::locale::classic();
>+ // PR libstdc++/119671 use-after-free formatting floating-point to wstring
>+ ws = std::format(cloc, L"{:L}", 0.5);
>+ VERIFY( ws == L"0.5" );
>+ // A locale with no name, but with the same facets as the C locale.
>+ std::locale locx(cloc, &std::use_facet<std::ctype<char>>(cloc));
>+ ws = std::format(locx, L"{:L}", 0.5);
>+ VERIFY( ws == L"0.5" );
>+ }
> }
>
>-void
>+CONSTEXPR void
> test_minmax()
> {
> auto check = []<typename T, typename U = std::make_unsigned_t<T>>(T, U = 0) {
>@@ -422,7 +441,7 @@ test_minmax()
> #endif
> }
>
>-void
>+CONSTEXPR void
> test_p1652r1() // printf corner cases in std::format
> {
> std::string s;
>@@ -436,27 +455,33 @@ test_p1652r1() // printf corner cases in std::format
> s = std::format("{:c}", c);
> VERIFY( s == "A" );
>
>- // Problem 3: "-000nan" is not a floating point value
>- double nan = std::numeric_limits<double>::quiet_NaN();
>- try {
>- s = std::vformat("{:0=6}", std::make_format_args(nan));
>- VERIFY( false );
>- } catch (const std::format_error&) {
>- }
>-
>- s = std::format("{:06}", nan);
>- VERIFY( s == " nan" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ // Problem 3: "-000nan" is not a floating point value
>+ double nan = std::numeric_limits<double>::quiet_NaN();
>+ try {
>+ s = std::vformat("{:0=6}", std::make_format_args(nan));
>+ VERIFY( false );
>+ } catch (const std::format_error&) {
>+ }
>+
>+ s = std::format("{:06}", nan);
>+ VERIFY( s == " nan" );
>+ }
>
> // Problem 4: bool needs a type format specifier
> s = std::format("{:s}", true);
> VERIFY( s == "true" );
>
>- // Problem 5: double does not roundtrip float
>- s = std::format("{}", 3.31f);
>- VERIFY( s == "3.31" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ // Problem 5: double does not roundtrip float
>+ s = std::format("{}", 3.31f);
>+ VERIFY( s == "3.31" );
>+ }
> }
>
>-void
>+CONSTEXPR void
> test_pointer()
> {
> void* p = nullptr;
>@@ -477,28 +502,31 @@ test_pointer()
> s = std::format("{:o<4},{:o>5},{:o^7}", p, pc, nullptr); // fill+align+width
> VERIFY( s == "0x0o,oo0x0,oo0x0oo" );
>
>- pc = p = &s;
>- str_int = std::format("{:#x}", reinterpret_cast<std::uintptr_t>(p));
>- s = std::format("{} {} {}", p, pc, nullptr);
>- VERIFY( s == (str_int + ' ' + str_int + " 0x0") );
>- str_int = std::format("{:#20x}", reinterpret_cast<std::uintptr_t>(p));
>- s = std::format("{:20} {:20p}", p, pc);
>- VERIFY( s == (str_int + ' ' + str_int) );
>+ if (!std::is_constant_evaluated())
>+ {
>+ pc = p = &s;
>+ str_int = std::format("{:#x}", reinterpret_cast<std::uintptr_t>(p));
>+ s = std::format("{} {} {}", p, pc, nullptr);
>+ VERIFY( s == (str_int + ' ' + str_int + " 0x0") );
>+ str_int = std::format("{:#20x}", reinterpret_cast<std::uintptr_t>(p));
>+ s = std::format("{:20} {:20p}", p, pc);
>+ VERIFY( s == (str_int + ' ' + str_int) );
>
> #if __cpp_lib_format >= 202304L
>- // P2510R3 Formatting pointers
>- s = std::format("{:06} {:07P} {:08p}", (void*)0, (const void*)0, nullptr);
>- VERIFY( s == "0x0000 0X00000 0x000000" );
>- str_int = std::format("{:#016x}", reinterpret_cast<std::uintptr_t>(p));
>- s = std::format("{:016} {:016}", p, pc);
>- VERIFY( s == (str_int + ' ' + str_int) );
>- str_int = std::format("{:#016X}", reinterpret_cast<std::uintptr_t>(p));
>- s = std::format("{:016P} {:016P}", p, pc);
>- VERIFY( s == (str_int + ' ' + str_int) );
>+ // P2510R3 Formatting pointers
>+ s = std::format("{:06} {:07P} {:08p}", (void*)0, (const void*)0, nullptr);
>+ VERIFY( s == "0x0000 0X00000 0x000000" );
>+ str_int = std::format("{:#016x}", reinterpret_cast<std::uintptr_t>(p));
>+ s = std::format("{:016} {:016}", p, pc);
>+ VERIFY( s == (str_int + ' ' + str_int) );
>+ str_int = std::format("{:#016X}", reinterpret_cast<std::uintptr_t>(p));
>+ s = std::format("{:016P} {:016P}", p, pc);
>+ VERIFY( s == (str_int + ' ' + str_int) );
> #endif
>+ }
> }
>
>-void
>+CONSTEXPR void
> test_bool()
> {
> std::string s;
>@@ -519,7 +547,7 @@ test_bool()
> VERIFY( s == "0 0x1 0X0" );
> }
>
>-void
>+CONSTEXPR void
> test_unicode()
> {
> #ifdef UNICODE
>@@ -579,13 +607,13 @@ test_unicode()
> #endif
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_no_args();
> test_unescaped();
> test_std_examples();
> test_alternate_forms();
>- test_locale();
> test_width();
> test_char();
> test_wchar();
>@@ -594,4 +622,21 @@ int main()
> test_pointer();
> test_bool();
> test_unicode();
>+
>+ if (!std::is_constant_evaluated())
>+ {
>+ test_infnan();
>+ test_locale();
>+ }
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/functions/format_to.cc b/libstdc++-v3/testsuite/std/format/functions/format_to.cc
>index 94e6262bc66..ec6816ddba9 100644
>--- a/libstdc++-v3/testsuite/std/format/functions/format_to.cc
>+++ b/libstdc++-v3/testsuite/std/format/functions/format_to.cc
>@@ -6,22 +6,31 @@
> #include <cstring>
> #include <testsuite_hooks.h>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> struct punct : std::numpunct<char>
> {
> std::string do_grouping() const override { return "\2"; }
> };
>
>-void
>+CONSTEXPR void
> test()
> {
> char buf[32] = { };
> auto out = std::format_to(buf, "test");
> VERIFY( out == buf+4 );
>
>- std::locale loc({}, new punct);
>- auto out2 = std::format_to(buf, loc, "{:Ld}", 12345);
>- VERIFY( out2 == buf+7 );
>- VERIFY( std::string_view(buf, out2 - buf) == "1,23,45" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ std::locale loc({}, new punct);
>+ auto out2 = std::format_to(buf, loc, "{:Ld}", 12345);
>+ VERIFY( out2 == buf+7 );
>+ VERIFY( std::string_view(buf, out2 - buf) == "1,23,45" );
>+ }
> }
>
> struct wpunct : std::numpunct<wchar_t>
>@@ -29,17 +38,20 @@ struct wpunct : std::numpunct<wchar_t>
> std::string do_grouping() const override { return "\2"; }
> };
>
>-void
>+CONSTEXPR void
> test_wchar()
> {
> wchar_t buf[32] = { };
> auto out = std::format_to(buf, L"123 + 456 = {}", 579);
> VERIFY( out == buf+15 );
>
>- std::locale loc({}, new wpunct);
>- auto out2 = std::format_to(buf, loc, L"{:Ld}", 12345);
>- VERIFY( out2 == buf+7 );
>- VERIFY( std::wstring_view(buf, out2 - buf) == L"1,23,45" );
>+ if (!std::is_constant_evaluated())
>+ {
>+ std::locale loc({}, new wpunct);
>+ auto out2 = std::format_to(buf, loc, L"{:Ld}", 12345);
>+ VERIFY( out2 == buf+7 );
>+ VERIFY( std::wstring_view(buf, out2 - buf) == L"1,23,45" );
>+ }
> }
>
> template<typename I>
>@@ -50,20 +62,20 @@ struct move_only_iterator
> using difference_type = iterator::difference_type;
> using iterator_category = std::output_iterator_tag;
>
>- move_only_iterator(iterator b) : base_(b) { }
>+ constexpr move_only_iterator(iterator b) : base_(b) { }
> move_only_iterator(move_only_iterator&&) = default;
> move_only_iterator& operator=(move_only_iterator&&) = default;
>
>- move_only_iterator& operator++() { ++base_; return *this; }
>- move_only_iterator operator++(int) { auto tmp = *this; ++base_; return tmp; }
>+ constexpr move_only_iterator& operator++() { ++base_; return *this; }
>+ constexpr move_only_iterator operator++(int) { auto tmp = *this; ++base_; return tmp; }
>
>- decltype(auto) operator*() { return *base_; }
>+ constexpr decltype(auto) operator*() { return *base_; }
>
> private:
> iterator base_;
> };
>
>-void
>+CONSTEXPR void
> test_move_only()
> {
> std::string str;
>@@ -79,7 +91,7 @@ test_move_only()
> VERIFY( std::wstring_view(vec.data(), vec.size()) == L"format hat!" );
> }
>
>-void
>+CONSTEXPR void
> test_pr110917()
> {
> // PR libstdc++/110917
>@@ -90,10 +102,22 @@ test_pr110917()
> VERIFY( ! std::memcmp(buf, "abc 123", 7) );
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test();
> test_wchar();
> test_move_only();
> test_pr110917();
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/functions/size.cc b/libstdc++-v3/testsuite/std/format/functions/size.cc
>index 1ece4108d85..16029bd5949 100644
>--- a/libstdc++-v3/testsuite/std/format/functions/size.cc
>+++ b/libstdc++-v3/testsuite/std/format/functions/size.cc
>@@ -4,7 +4,13 @@
> #include <string>
> #include <testsuite_hooks.h>
>
>-void
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
>+CONSTEXPR void
> test()
> {
> auto n = std::formatted_size("");
>@@ -24,7 +30,7 @@ test()
> VERIFY( n == 5 );
> }
>
>-void
>+CONSTEXPR void
> test_wchar()
> {
> auto n = std::formatted_size(L"");
>@@ -44,8 +50,19 @@ test_wchar()
> VERIFY( n == 5 );
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test();
> test_wchar();
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/ranges/format_kind.cc b/libstdc++-v3/testsuite/std/format/ranges/format_kind.cc
>index 1450fbaebc5..49c8246fee2 100644
>--- a/libstdc++-v3/testsuite/std/format/ranges/format_kind.cc
>+++ b/libstdc++-v3/testsuite/std/format/ranges/format_kind.cc
>@@ -12,6 +12,12 @@
> #include <unordered_set>
> #include <vector>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> static_assert( std::format_kind<std::vector<int>> == std::range_format::sequence );
> static_assert( std::format_kind<std::deque<int>> == std::range_format::sequence );
> static_assert( std::format_kind<std::list<int>> == std::range_format::sequence );
>@@ -64,7 +70,8 @@ struct CustFormat : std::vector<T>
> template<typename T, std::range_format rf>
> constexpr auto std::format_kind<CustFormat<T, rf>> = rf;
>
>-void test_override()
>+CONSTEXPR bool
>+test_override()
> {
> CustFormat<int, std::range_format::disabled> disabledf;
> static_assert( !std::formattable<decltype(disabledf), char> );
>@@ -88,8 +95,14 @@ void test_override()
> VERIFY( std::format("{}", debugf) == R"("abcd")" );
> // Support precision as string do
> VERIFY( std::format("{:.3}", debugf) == R"("ab)" );
>+
>+ return true;
> }
>
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_override());
>+#endif
>+
> int main()
> {
> test_override();
>diff --git a/libstdc++-v3/testsuite/std/format/ranges/formatter.cc b/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
>index a50c5b1033f..947e6c3bc60 100644
>--- a/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
>+++ b/libstdc++-v3/testsuite/std/format/ranges/formatter.cc
>@@ -6,6 +6,12 @@
> #include <vector>
> #include <span>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> #define WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
> #define WIDEN(S) WIDEN_(CharT, S)
>
>@@ -32,7 +38,7 @@ struct std::formatter<MyVector<T, Formatter>, CharT>
> { return _formatter.parse(pc); }
>
> template<typename Out>
>- typename std::basic_format_context<Out, CharT>::iterator
>+ CONSTEXPR std::basic_format_context<Out, CharT>::iterator
> format(const MyVector<T, Formatter>& mv,
> std::basic_format_context<Out, CharT>& fc) const
> { return _formatter.format(mv, fc); }
>@@ -42,7 +48,7 @@ private:
> };
>
> template<typename CharT, template<typename, typename> class Formatter>
>-void
>+CONSTEXPR void
> test_default()
> {
> MyVector<int, Formatter> vec{1, 2, 3};
>@@ -94,7 +100,7 @@ test_default()
> }
>
> template<typename CharT, template<typename, typename> class Formatter>
>-void
>+CONSTEXPR void
> test_override()
> {
> MyVector<CharT, Formatter> vc{'a', 'b', 'c', 'd'};
>@@ -115,7 +121,8 @@ test_override()
> }
>
> template<template<typename, typename> class Formatter>
>-void test_outputs()
>+CONSTEXPR void
>+test_outputs()
> {
> test_default<char, Formatter>();
> test_default<wchar_t, Formatter>();
>@@ -123,7 +130,7 @@ void test_outputs()
> test_override<wchar_t, Formatter>();
> }
>
>-void
>+CONSTEXPR void
> test_nested()
> {
> MyVector<MyVector<int>> v
>@@ -152,7 +159,8 @@ struct std::formatter<MyFlatMap, CharT>
> : std::range_formatter<MyFlatMap::reference>
> {};
>
>-void test_const_ref_type_mismatch()
>+CONSTEXPR void
>+test_const_ref_type_mismatch()
> {
> MyFlatMap m{{1, 11}, {2, 22}};
> std::string res = std::format("{:m}", m);
>@@ -163,13 +171,15 @@ template<typename T, typename CharT>
> using VectorFormatter = std::formatter<std::vector<T>, CharT>;
>
> template<template<typename> typename Range>
>-void test_nonblocking()
>+CONSTEXPR void
>+test_nonblocking()
> {
> static_assert(!std::enable_nonlocking_formatter_optimization<
> Range<int>>);
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_outputs<std::range_formatter>();
> test_outputs<VectorFormatter>();
>@@ -179,4 +189,15 @@ int main()
> test_nonblocking<std::span>();
> test_nonblocking<std::vector>();
> test_nonblocking<MyVector>();
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/ranges/sequence.cc b/libstdc++-v3/testsuite/std/format/ranges/sequence.cc
>index 7fb65f9c551..cba53b46270 100644
>--- a/libstdc++-v3/testsuite/std/format/ranges/sequence.cc
>+++ b/libstdc++-v3/testsuite/std/format/ranges/sequence.cc
>@@ -1,5 +1,5 @@
> // { dg-do run { target c++23 } }
>-// { dg-options "-fexec-charset=UTF-8" }
>+// { dg-options "-fexec-charset=UTF-8 -fconstexpr-ops-limit=5000000000" }
> // { dg-timeout-factor 2 }
>
> #include <array>
>@@ -12,6 +12,12 @@
> #include <testsuite_iterators.h>
> #include <vector>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> struct NotFormattable
> {};
>
>@@ -19,7 +25,7 @@ static_assert(!std::formattable<std::vector<NotFormattable>, char>);
> static_assert(!std::formattable<std::span<NotFormattable>, wchar_t>);
>
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const char* str, Args&&... args)
> {
> try {
>@@ -31,7 +37,7 @@ is_format_string_for(const char* str, Args&&... args)
> }
>
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const wchar_t* str, Args&&... args)
> {
> try {
>@@ -43,7 +49,8 @@ is_format_string_for(const wchar_t* str, Args&&... args)
> }
>
> template<typename Rg, typename CharT>
>-bool is_range_formatter_spec_for(CharT const* spec, Rg&& rg)
>+CONSTEXPR bool
>+is_range_formatter_spec_for(CharT const* spec, Rg&& rg)
> {
> using V = std::remove_cvref_t<std::ranges::range_reference_t<Rg>>;
> std::range_formatter<V, CharT> fmt;
>@@ -56,7 +63,7 @@ bool is_range_formatter_spec_for(CharT const* spec, Rg&& rg)
> }
> }
>
>-void
>+CONSTEXPR void
> test_format_string()
> {
> // invalid format spec 'p'
>@@ -79,7 +86,8 @@ test_format_string()
> #define WIDEN(S) WIDEN_(CharT, S)
>
> template<typename CharT, typename Range, typename Storage>
>-void test_output()
>+CONSTEXPR void
>+test_output()
> {
> using Sv = std::basic_string_view<CharT>;
> using T = std::ranges::range_value_t<Range>;
>@@ -153,25 +161,30 @@ void test_output()
> }
>
> template<typename Cont>
>-void test_output_cont()
>+CONSTEXPR void
>+test_output_cont()
> {
> test_output<char, Cont&, Cont>();
> test_output<wchar_t, Cont const&, Cont>();
> }
>
> template<typename View>
>-void test_output_view()
>+CONSTEXPR void
>+test_output_view()
> {
> test_output<char, View, int[3]>();
> test_output<wchar_t, View, int[3]>();
> }
>
>-void
>+CONSTEXPR void
> test_outputs()
> {
> using namespace __gnu_test;
> test_output_cont<std::vector<int>>();
>- test_output_cont<std::list<int>>();
>+
>+ if (!std::is_constant_evaluated())
>+ test_output_cont<std::list<int>>();
>+
> test_output_cont<std::array<int, 3>>();
>
> test_output_view<std::span<int>>();
>@@ -185,7 +198,7 @@ test_outputs()
> test_output_view<test_forward_range<const int>>();
> }
>
>-void
>+CONSTEXPR void
> test_nested()
> {
> std::vector<std::vector<int>> v
>@@ -201,7 +214,8 @@ test_nested()
> VERIFY( res == "+[01, 02, 11, 12]+" );
> }
>
>-bool strip_quote(std::string_view& v)
>+CONSTEXPR bool
>+strip_quote(std::string_view& v)
> {
> if (!v.starts_with('"'))
> return false;
>@@ -209,7 +223,8 @@ bool strip_quote(std::string_view& v)
> return true;
> }
>
>-bool strip_prefix(std::string_view& v, std::string_view expected, bool quoted = false)
>+CONSTEXPR bool
>+strip_prefix(std::string_view& v, std::string_view expected, bool quoted = false)
> {
> if (quoted && !strip_quote(v))
> return false;
>@@ -221,7 +236,8 @@ bool strip_prefix(std::string_view& v, std::string_view expected, bool quoted =
> return true;
> }
>
>-bool strip_squares(std::string_view& v)
>+CONSTEXPR bool
>+strip_squares(std::string_view& v)
> {
> if (!v.starts_with('[') || !v.ends_with(']'))
> return false;
>@@ -230,7 +246,8 @@ bool strip_squares(std::string_view& v)
> return true;
> }
>
>-bool strip_prefix(std::string_view& v, size_t n, char c)
>+CONSTEXPR bool
>+strip_prefix(std::string_view& v, size_t n, char c)
> {
> size_t pos = v.find_first_not_of(c);
> if (pos == std::string_view::npos)
>@@ -241,7 +258,8 @@ bool strip_prefix(std::string_view& v, size_t n, char c)
> return true;
> }
>
>-void test_padding()
>+CONSTEXPR void
>+test_padding()
> {
> std::string res;
> std::string_view resv;
>@@ -323,10 +341,22 @@ void test_padding()
> VERIFY( check_elems(resv, false) );
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_format_string();
> test_outputs();
> test_nested();
> test_padding();
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/string.cc b/libstdc++-v3/testsuite/std/format/string.cc
>index ee987a15ec3..004690ad8da 100644
>--- a/libstdc++-v3/testsuite/std/format/string.cc
>+++ b/libstdc++-v3/testsuite/std/format/string.cc
>@@ -1,10 +1,17 @@
> // { dg-do run { target c++20 } }
>+// { dg-options "-fconstexpr-ops-limit=100000000" }
>
> #include <format>
> #include <testsuite_hooks.h>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const char* str, Args&&... args)
> {
> try {
>@@ -16,7 +23,7 @@ is_format_string_for(const char* str, Args&&... args)
> }
>
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const wchar_t* str, Args&&... args)
> {
> try {
>@@ -27,7 +34,7 @@ is_format_string_for(const wchar_t* str, Args&&... args)
> }
> }
>
>-void
>+CONSTEXPR void
> test_no_args()
> {
> VERIFY( is_format_string_for("") );
>@@ -42,7 +49,7 @@ test_no_args()
> VERIFY( ! is_format_string_for("{{{{{") );
> }
>
>-void
>+CONSTEXPR void
> test_indexing()
> {
> VERIFY( is_format_string_for("{} to {}", "a", "b") ); // automatic indexing
>@@ -68,7 +75,7 @@ constexpr bool escaped_strings_supported = true;
> constexpr bool escaped_strings_supported = false;
> #endif
>
>-void
>+CONSTEXPR void
> test_format_spec()
> {
> VERIFY( is_format_string_for("{:}", 1) );
>@@ -78,9 +85,14 @@ test_format_spec()
> VERIFY( is_format_string_for("{0:} {0:c}", 'c') );
> VERIFY( is_format_string_for("{0:p} {0:}", nullptr) );
> VERIFY( is_format_string_for("{:d} {:+d}", true, true) );
>- VERIFY( is_format_string_for("{:0<-#03Ld}", 1) );
>- VERIFY( is_format_string_for("{1:0<-#03.4Lf}", 1, 2.3) );
>- VERIFY( is_format_string_for("{1:3.3f}", 1, 2.3) );
>+
>+ if (!std::is_constant_evaluated())
>+ {
>+ VERIFY( is_format_string_for("{:0<-#03Ld}", 1) );
>+ VERIFY( is_format_string_for("{1:0<-#03.4Lf}", 1, 2.3) );
>+ VERIFY( is_format_string_for("{1:3.3f}", 1, 2.3) );
>+ }
>+
> VERIFY( is_format_string_for("{:#d}", 'c') );
> VERIFY( is_format_string_for("{:#d}", true) );
> VERIFY( is_format_string_for("{0:s} {0:?}", "str") == escaped_strings_supported );
>@@ -130,13 +142,16 @@ test_format_spec()
> VERIFY( ! is_format_string_for("{:3.3p}", nullptr) );
>
> // Dynamic precision arg must be a standard integer type.
>- VERIFY( ! is_format_string_for("{:.{}f}", 1.0, 1.5) );
>- VERIFY( ! is_format_string_for("{:.{}f}", 1.0, true) );
>- VERIFY( ! is_format_string_for("{:.{}f}", 1.0, "str") );
>- VERIFY( ! is_format_string_for("{:.{}f}", 1.0, nullptr) );
>+ if (!std::is_constant_evaluated())
>+ {
>+ VERIFY( ! is_format_string_for("{:.{}f}", 1.0, 1.5) );
>+ VERIFY( ! is_format_string_for("{:.{}f}", 1.0, true) );
>+ VERIFY( ! is_format_string_for("{:.{}f}", 1.0, "str") );
>+ VERIFY( ! is_format_string_for("{:.{}f}", 1.0, nullptr) );
> #ifdef __SIZEOF_INT128__
>- VERIFY( ! is_format_string_for("{:{}f}", 1.0, static_cast<unsigned __int128>(1)) );
>+ VERIFY( ! is_format_string_for("{:{}f}", 1.0, static_cast<unsigned __int128>(1)) );
> #endif
>+ }
>
> // Invalid presentation types for integers.
> VERIFY( ! is_format_string_for("{:f}", 1) );
>@@ -164,7 +179,7 @@ test_format_spec()
> VERIFY( ! is_format_string_for(L"{:9999999}", 1) );
> }
>
>-void
>+CONSTEXPR void
> test_pr110862()
> {
> try {
>@@ -178,7 +193,7 @@ test_pr110862()
> }
> }
>
>-void
>+CONSTEXPR void
> test_pr110974()
> {
> try {
>@@ -197,11 +212,23 @@ test_pr110974()
> }
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_no_args();
> test_indexing();
> test_format_spec();
> test_pr110862();
> test_pr110974();
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/format/tuple.cc b/libstdc++-v3/testsuite/std/format/tuple.cc
>index eace82730f0..dc7b860a902 100644
>--- a/libstdc++-v3/testsuite/std/format/tuple.cc
>+++ b/libstdc++-v3/testsuite/std/format/tuple.cc
>@@ -1,5 +1,5 @@
> // { dg-do run { target c++23 } }
>-// { dg-options "-fexec-charset=UTF-8" }
>+// { dg-options "-fexec-charset=UTF-8 -fconstexpr-ops-limit=500000000" }
> // { dg-timeout-factor 2 }
>
> #include <format>
>@@ -8,6 +8,12 @@
> #include <tuple>
> #include <utility>
>
>+#ifdef __glibcxx_constexpr_format
>+# define CONSTEXPR constexpr
>+#else
>+# define CONSTEXPR
>+#endif
>+
> struct NotFormattable
> {};
>
>@@ -15,7 +21,7 @@ static_assert( !std::formattable<std::pair<int, NotFormattable>, char> );
> static_assert( !std::formattable<std::tuple<int, NotFormattable, int>, wchar_t> );
>
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const char* str, Args&&... args)
> {
> try {
>@@ -27,7 +33,7 @@ is_format_string_for(const char* str, Args&&... args)
> }
>
> template<typename... Args>
>-bool
>+CONSTEXPR bool
> is_format_string_for(const wchar_t* str, Args&&... args)
> {
> try {
>@@ -41,7 +47,7 @@ is_format_string_for(const wchar_t* str, Args&&... args)
> #define WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
> #define WIDEN(S) WIDEN_(CharT, S)
>
>-void
>+CONSTEXPR void
> test_format_string()
> {
> // invalid format stringss
>@@ -123,7 +129,8 @@ void test_multi()
> }
>
> template<typename CharT, typename Tuple>
>-void test_empty()
>+CONSTEXPR void
>+test_empty()
> {
> std::basic_string<CharT> res;
>
>@@ -142,7 +149,8 @@ void test_empty()
> }
>
> template<typename CharT, typename Pair>
>-void test_pair()
>+CONSTEXPR void
>+test_pair()
> {
> using Ft = std::remove_cvref_t<std::tuple_element_t<0, Pair>>;
> using St = std::remove_cvref_t<std::tuple_element_t<1, Pair>>;
>@@ -167,7 +175,8 @@ void test_pair()
> }
>
> template<typename CharT, template<typename, typename> class PairT>
>-void test_pair_e()
>+CONSTEXPR void
>+test_pair_e()
> {
> test_pair<CharT, PairT<int, std::basic_string<CharT>>>();
> test_pair<CharT, PairT<int, const CharT*>>();
>@@ -196,7 +205,7 @@ struct std::formatter<MyPair<Pair>, CharT>
> { return _formatter.parse(pc); }
>
> template<typename Out>
>- typename std::basic_format_context<Out, CharT>::iterator
>+ CONSTEXPR typename std::basic_format_context<Out, CharT>::iterator
> format(const MyPair<Pair>& mp,
> std::basic_format_context<Out, CharT>& fc) const
> { return _formatter.format(mp, fc); }
>@@ -206,7 +215,8 @@ private:
> };
>
> template<typename CharT, template<typename, typename> class PairT>
>-void test_custom()
>+CONSTEXPR void
>+test_custom()
> {
> std::basic_string<CharT> res;
> MyPair<PairT<int, const CharT*>> c1(1, WIDEN("abc"));
>@@ -228,9 +238,12 @@ void test_custom()
> }
>
> template<typename CharT>
>-void test_outputs()
>+CONSTEXPR void
>+test_outputs()
> {
>- test_multi<CharT>();
>+ if (!std::is_constant_evaluated())
>+ test_multi<CharT>();
>+
> test_empty<CharT, std::tuple<>>();
> test_pair_e<CharT, std::pair>();
> test_pair_e<CharT, std::tuple>();
>@@ -238,7 +251,8 @@ void test_outputs()
> test_custom<CharT, std::tuple>();
> }
>
>-void test_nested()
>+CONSTEXPR void
>+test_nested()
> {
> std::string res;
> std::tuple<std::tuple<>, std::pair<int, std::string>> tt{{}, {1, "abc"}};
>@@ -251,7 +265,8 @@ void test_nested()
> VERIFY( res == R"((): (1, "abc"))" );
> }
>
>-bool strip_quote(std::string_view& v)
>+CONSTEXPR bool
>+strip_quote(std::string_view& v)
> {
> if (!v.starts_with('"'))
> return false;
>@@ -259,7 +274,8 @@ bool strip_quote(std::string_view& v)
> return true;
> }
>
>-bool strip_prefix(std::string_view& v, std::string_view expected, bool quoted = false)
>+CONSTEXPR bool
>+strip_prefix(std::string_view& v, std::string_view expected, bool quoted = false)
> {
> if (quoted && !strip_quote(v))
> return false;
>@@ -271,7 +287,8 @@ bool strip_prefix(std::string_view& v, std::string_view expected, bool quoted =
> return true;
> }
>
>-bool strip_parens(std::string_view& v)
>+CONSTEXPR bool
>+strip_parens(std::string_view& v)
> {
> if (!v.starts_with('(') || !v.ends_with(')'))
> return false;
>@@ -280,7 +297,8 @@ bool strip_parens(std::string_view& v)
> return true;
> }
>
>-bool strip_prefix(std::string_view& v, size_t n, char c)
>+CONSTEXPR bool
>+strip_prefix(std::string_view& v, size_t n, char c)
> {
> size_t pos = v.find_first_not_of(c);
> if (pos == std::string_view::npos)
>@@ -291,7 +309,8 @@ bool strip_prefix(std::string_view& v, size_t n, char c)
> return true;
> }
>
>-void test_padding()
>+CONSTEXPR void
>+test_padding()
> {
> std::string res;
> std::string_view resv;
>@@ -351,13 +370,14 @@ struct std::formatter<Custom, CharT>
> { return pc.begin(); }
>
> template<typename Out>
>- typename std::basic_format_context<Out, CharT>::iterator
>+ CONSTEXPR typename std::basic_format_context<Out, CharT>::iterator
> format(Custom, const std::basic_format_context<Out, CharT>& fc) const
> { return fc.out(); }
> };
>
> template<template<typename...> typename Tuple>
>-void test_nonblocking()
>+CONSTEXPR void
>+test_nonblocking()
> {
> static_assert(std::enable_nonlocking_formatter_optimization<
> Tuple<int, float>>);
>@@ -374,7 +394,8 @@ void test_nonblocking()
> Tuple<Custom&, float&>>);
> }
>
>-int main()
>+CONSTEXPR bool
>+test_all()
> {
> test_format_string();
> test_outputs<char>();
>@@ -384,4 +405,15 @@ int main()
>
> test_nonblocking<std::pair>();
> test_nonblocking<std::tuple>();
>+
>+ return true;
>+}
>+
>+#ifdef __glibcxx_constexpr_format
>+static_assert(test_all());
>+#endif
>+
>+int main()
>+{
>+ test_all();
> }
>diff --git a/libstdc++-v3/testsuite/std/time/format/data_not_present_neg.cc b/libstdc++-v3/testsuite/std/time/format/data_not_present_neg.cc
>index cb8f916f216..86f3b618599 100644
>--- a/libstdc++-v3/testsuite/std/time/format/data_not_present_neg.cc
>+++ b/libstdc++-v3/testsuite/std/time/format/data_not_present_neg.cc
>@@ -161,4 +161,5 @@ auto si7 = std::format("{:%Q}", sys_info()); // { dg-error "call to consteval fu
> auto si8 = std::format("{:%Z}", sys_info()); // { dg-error "call to consteval function" "" { target cxx11_abi } }
> #endif
>
>-// { dg-error "call to non-'constexpr' function" "" { target *-*-* } 0 }
>+// { dg-error "call to non-'constexpr' function" "" { target c++23_down } 0 }
>+// { dg-error "'std::terminate' called after throwing an exception" "" { target { ! c++23_down } } 0 }
>--
>2.54.0
>
>
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