[gcc r10-10309] libstdc++: Don't check always-true condition [PR101965]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:30033d9bb9d5e5303fadf448999f4f27e2693ed6

commit r10-10309-g30033d9bb9d5e5303fadf448999f4f27e2693ed6
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Aug 19 13:05:54 2021 +0100

    libstdc++: Don't check always-true condition [PR101965]
    
    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/101965
            * include/std/charconv (__to_chars_i): Remove redundant check.
    
    (cherry picked from commit 85a709595005b5df4b2ee9d81717a5df19c0023f)

Diff:
---
 libstdc++-v3/include/std/charconv | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/std/charconv b/libstdc++-v3/include/std/charconv
index cc7dd0e3758..daad423570a 100644
--- a/libstdc++-v3/include/std/charconv
+++ b/libstdc++-v3/include/std/charconv
@@ -335,12 +335,10 @@ namespace __detail
 	  *__first = '0';
 	  return { __first + 1, errc{} };
 	}
-
-      if _GLIBCXX17_CONSTEXPR (std::is_signed<_Tp>::value)
+      else if _GLIBCXX17_CONSTEXPR (std::is_signed<_Tp>::value)
 	if (__value < 0)
 	  {
-	    if (__builtin_expect(__first != __last, 1))
-	      *__first++ = '-';
+	    *__first++ = '-';
 	    __unsigned_val = _Up(~__value) + _Up(1);
 	  }