[Bug libstdc++/107811] New: libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[Bug libstdc++/107811] New: libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

            Bug ID: 107811
           Summary: libstdc++-v3/src/c++17/floating_from_chars.cc:787:9:
                    error: 'fast_float' has not been declared
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---
            Target: msp430-elf

Building for msp430-elf fails in libstdc++

/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc: In
function 'std::from_chars_result
std::{anonymous}::__floating_from_chars_hex(const char*, const char*, T&)':
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:787:9:
error: 'fast_float' has not been declared
  787 |       = fast_float::binary_format<T>::mantissa_explicit_bits();
      |         ^~~~~~~~~~
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:787:36:
error: expected primary-expression before '>' token
  787 |       = fast_float::binary_format<T>::mantissa_explicit_bits();
      |                                    ^
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:787:39:
error: '::mantissa_explicit_bits' has not been declared
  787 |       = fast_float::binary_format<T>::mantissa_explicit_bits();
      |                                       ^~~~~~~~~~~~~~~~~~~~~~
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:790:24:
error: 'fast_float' was not declared in this scope
  790 |         : is_same_v<T, fast_float::floating_type_float16_t> ? 5 : 8;
      |                        ^~~~~~~~~~
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:790:11:
error: parse error in template argument list
  790 |         : is_same_v<T, fast_float::floating_type_float16_t> ? 5 : 8;
      |           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:948:30:
error: parse error in template argument list
  948 |                           || is_same_v<T,
      |                              ^~~~~~~~~~~~
  949 |                                       
fast_float::floating_type_bfloat16_t>)
      |                                       
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/jwakely/src/gcc/gcc/libstdc++-v3/src/c++17/floating_from_chars.cc:1133:24:
error: parse error in template argument list
 1133 |     else if constexpr (is_same_v<T,
fast_float::floating_type_bfloat16_t>)
      |                       
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Bug libstdc++/107811] libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Oops.

Does:
2022-11-22  Jakub Jelinek  <jakub@redhat.com>

        PR libstdc++/107811
        * src/c++17/floating_from_chars.cc (__floating_from_chars_hex): Guard
        fast_float uses with #if USE_LIB_FAST_FLOAT and for mantissa_bits and
        exponent_bits provide a fallback.

--- libstdc++-v3/src/c++17/floating_from_chars.cc.jj    2022-11-08
09:54:37.533397224 +0100
+++ libstdc++-v3/src/c++17/floating_from_chars.cc       2022-11-22
14:03:10.365474110 +0100
@@ -783,11 +783,16 @@ namespace
     using uint_t = conditional_t<is_same_v<T, float>, uint32_t,
                                 conditional_t<is_same_v<T, double>, uint64_t,
                                               uint16_t>>;
+#if USE_LIB_FAST_FLOAT
     constexpr int mantissa_bits
       = fast_float::binary_format<T>::mantissa_explicit_bits();
     constexpr int exponent_bits
       = is_same_v<T, double> ? 11
        : is_same_v<T, fast_float::floating_type_float16_t> ? 5 : 8;
+#else
+    constexpr int mantissa_bits = is_same_v<T, float> ? 23 : 52;
+    constexpr int exponent_bits = is_same_v<T, float> ? 8 : 11;
+#endif
     constexpr int exponent_bias = (1 << (exponent_bits - 1)) - 1;

     __glibcxx_requires_valid_range(first, last);
@@ -945,8 +950,11 @@ namespace
        else if (mantissa_idx >= -4)
          {
            if constexpr (is_same_v<T, float>
+#if USE_LIB_FAST_FLOAT
                          || is_same_v<T,
-                                      fast_float::floating_type_bfloat16_t>)
+                                      fast_float::floating_type_bfloat16_t>
+#endif
+                        )
              {
                __glibcxx_assert(mantissa_idx == -1);
                mantissa |= hexit >> 1;
@@ -1130,6 +1138,7 @@ namespace
       }
     if constexpr (is_same_v<T, float> || is_same_v<T, double>)
       memcpy(&value, &result, sizeof(result));
+#if USE_LIB_FAST_FLOAT
     else if constexpr (is_same_v<T, fast_float::floating_type_bfloat16_t>)
       {
        uint32_t res = uint32_t{result} << 16;
@@ -1156,6 +1165,7 @@ namespace
                 | ((uint32_t{result} & 0x8000) << 16));
        memcpy(value.x, &res, sizeof(res));
       }
+#endif

     return {first, errc{}};
   }

fix that?

[Bug libstdc++/107811] libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |13.0

[Bug libstdc++/107811] libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Yes it does

[Bug libstdc++/107811] libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:e6a32c12b4ef87c084d29863c79503344126d101

commit r13-4263-ge6a32c12b4ef87c084d29863c79503344126d101
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Nov 23 11:53:54 2022 +0100

    libstdc++: Fix libstdc++ build on some targets [PR107811]

    fast_float library relies on size_t being 32-bit or larger and float/double
    being IEEE single/double.  Otherwise we only use strtod/strtof.
    In 3 spots I've used fast_float namespace stuff unconditionally in one
    function, which breaks the build if fast_float is disabled.

    2022-11-23  Jakub Jelinek  <jakub@redhat.com>

            PR libstdc++/107811
            * src/c++17/floating_from_chars.cc (__floating_from_chars_hex):
Guard
            fast_float uses with #if USE_LIB_FAST_FLOAT and for mantissa_bits
and
            exponent_bits provide a fallback.

[Bug libstdc++/107811] libstdc++-v3/src/c++17/floating_from_chars.cc:787:9: error: 'fast_float' has not been declared

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107811

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed then.