[gcc r13-4819] libstdc++: Don't call 4-5 argument to_chars with chars_format{}

[gcc r13-4819] libstdc++: Don't call 4-5 argument to_chars with chars_format{}

[Jakub Jelinek]

https://gcc.gnu.org/g:3102b57f3105a301e54d7dc0586eb8e2b1724891

commit r13-4819-g3102b57f3105a301e54d7dc0586eb8e2b1724891
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Dec 21 09:04:06 2022 +0100

    libstdc++: Don't call 4-5 argument to_chars with chars_format{}
    
    In Fedora build libstdc++.so is built with assertions enabled and
    FAIL: 20_util/to_chars/float128_c++23.cc execution test
    was failing on all arches.  The problem is that it called 5 argument version
    of to_chars with chars_format{}, which C++ says is invalid:
    http://eel.is/c++draft/charconv.to.chars#12
    Preconditions: fmt has the value of one of the enumerators of chars_format.
    
    The following patch fixes it by skipping the second part of the test
    which needs the 5 argument to_chars for chars_format{}, but because
    it is strictly speaking invalid also for 4 argument to_chars, it uses
    3 argument to_chars instead of 4 argument to_chars with last argument
    chars_format{}.
    
    2022-12-21  Jakub Jelinek  <jakub@redhat.com>
    
            * testsuite/20_util/to_chars/float16_c++23.cc (test): Use 3 argument
            std::to_chars if fmt is std::chars_format{}, rather than 4 argument.
            * testsuite/20_util/to_chars/float128_c++23.cc (test): Likewise, and
            skip second part of testing that requires 5 argument std::to_chars.

Diff:
---
 libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc | 11 +++++++----
 libstdc++-v3/testsuite/20_util/to_chars/float16_c++23.cc  | 13 ++++++++++---
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc b/libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc
index 735a507827a..32b328bbd7e 100644
--- a/libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc
+++ b/libstdc++-v3/testsuite/20_util/to_chars/float128_c++23.cc
@@ -60,7 +60,9 @@ test(std::chars_format fmt = std::chars_format{})
   char str1[10000], str2[10000];
   for (auto u : tests)
     {
-      auto [ptr1, ec1] = std::to_chars(str1, str1 + sizeof(str1), u, fmt);
+      auto [ptr1, ec1] = (fmt == std::chars_format{}
+			  ? std::to_chars(str1, str1 + sizeof(str1), u)
+			  : std::to_chars(str1, str1 + sizeof(str1), u, fmt));
       VERIFY( ec1 == std::errc() );
 //    std::cout << u << ' ' << std::string_view (str1, ptr1) << '\n';
       if (fmt == std::chars_format::fixed)
@@ -77,13 +79,14 @@ test(std::chars_format fmt = std::chars_format{})
       VERIFY( ec4 == std::errc() && ptr4 == ptr1 );
       VERIFY( u == v );
 
+      if (fmt == std::chars_format{})
+	continue;
+
       auto [ptr5, ec5] = std::to_chars(str1, str1 + sizeof(str1), u, fmt, 90);
       VERIFY( ec5 == std::errc() );
 //    std::cout << u << ' ' << std::string_view (str1, ptr5) << '\n';
       v = 4.0f128;
-      auto [ptr6, ec6] = std::from_chars(str1, ptr5, v,
-					 fmt == std::chars_format{}
-					 ? std::chars_format::general : fmt);
+      auto [ptr6, ec6] = std::from_chars(str1, ptr5, v, fmt);
       VERIFY( ec6 == std::errc() && ptr6 == ptr5 );
       if (fmt == std::chars_format::fixed && u > 0.0f128 && u < 0.000001f128)
 	VERIFY( v == 0.0 );
diff --git a/libstdc++-v3/testsuite/20_util/to_chars/float16_c++23.cc b/libstdc++-v3/testsuite/20_util/to_chars/float16_c++23.cc
index db935377c1c..c51f802cf25 100644
--- a/libstdc++-v3/testsuite/20_util/to_chars/float16_c++23.cc
+++ b/libstdc++-v3/testsuite/20_util/to_chars/float16_c++23.cc
@@ -36,9 +36,16 @@ test(std::chars_format fmt = std::chars_format{})
   for (int i = 0; i <= (unsigned short) ~0; ++i)
     {
       u.s = i;
-      auto [ptr1, ec1] = std::to_chars(str1, str1 + sizeof(str1), u.f, fmt);
-      auto [ptr2, ec2] = std::to_chars(str2, str2 + sizeof(str2), std::float32_t(u.f), fmt);
-      VERIFY( ec1 == std::errc() && ec2 == std::errc());
+      auto [ptr1, ec1] = (fmt == std::chars_format{}
+			  ? std::to_chars(str1, str1 + sizeof(str1), u.f)
+			  : std::to_chars(str1, str1 + sizeof(str1), u.f,
+					  fmt));
+      auto [ptr2, ec2] = (fmt == std::chars_format{}
+			  ? std::to_chars(str2, str2 + sizeof(str2),
+					  std::float32_t(u.f))
+			  : std::to_chars(str2, str2 + sizeof(str2),
+					  std::float32_t(u.f), fmt));
+      VERIFY( ec1 == std::errc() && ec2 == std::errc() );
 //    std::cout << i << ' ' << std::string_view (str1, ptr1)
 //	<< '\t' << std::string_view (str2, ptr2) << '\n';
       if (fmt == std::chars_format::fixed)