[gcc r16-1074] libstdc++: Use explicit cast to unsigned in std::rotr and std::rotl

[Jonathan Wakely]

https://gcc.gnu.org/g:f12151e527d8d1b39a26b196f3de768c7edce5d0

commit r16-1074-gf12151e527d8d1b39a26b196f3de768c7edce5d0
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu May 29 11:29:38 2025 +0100

    libstdc++: Use explicit cast to unsigned in std::rotr and std::rotl
    
    This suppresses some -Wsign-conversion warnings from Clang when
    compiling with -Wsystem-headers.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/bit (__rotl, __rotr): Use static_cast for
            conversion from int to unsigned.
    
    Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>

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

diff --git a/libstdc++-v3/include/std/bit b/libstdc++-v3/include/std/bit
index 5187c96182f5..fd75edf6554a 100644
--- a/libstdc++-v3/include/std/bit
+++ b/libstdc++-v3/include/std/bit
@@ -166,7 +166,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  // Variant for power of two _Nd which the compiler can
 	  // easily pattern match.
 	  constexpr unsigned __uNd = _Nd;
-	  const unsigned __r = __s;
+	  const auto __r = static_cast<unsigned>(__s);
 	  return (__x << (__r % __uNd)) | (__x >> ((-__r) % __uNd));
 	}
       const int __r = __s % _Nd;
@@ -188,7 +188,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	  // Variant for power of two _Nd which the compiler can
 	  // easily pattern match.
 	  constexpr unsigned __uNd = _Nd;
-	  const unsigned __r = __s;
+	  const auto __r = static_cast<unsigned>(__s);
 	  return (__x >> (__r % __uNd)) | (__x << ((-__r) % __uNd));
 	}
       const int __r = __s % _Nd;