Avoid narrowing warnings in __bitset constructor

When <bitset> is compiled with warnings enabled, on a platform where
size_t is 4 bytes, it results in errors similar to:

    bitset:265:16: error: non-constant-expression cannot be narrowed
    from type 'unsigned long long' to '__storage_type' (aka 'unsigned
    int') in initializer list [-Wc++11-narrowing]
        : __first_{__v, __v >> __bits_per_word}
                   ^~~
    bitset:676:52: note: in instantiation of member function
    'std::__1::__bitset<2, 53>::__bitset' requested here
            bitset(unsigned long long __v) _NOEXCEPT : base(__v) {}
                                                       ^

Fix these by casting the initializer list elements to __storage_type.

Reviewers: mclow.lists, EricWF
Differential Revision: https://reviews.llvm.org/D23960

llvm-svn: 280543

diff --git a/libcxx/include/bitset b/libcxx/include/bitset
index 2ad9545..edc6c13 100644 (file)
--- a/libcxx/include/bitset
+++ b/libcxx/include/bitset
@@ -259,7 +259,7 @@ __bitset<_N_words, _Size>::__bitset(unsigned long long __v) _NOEXCEPT
 #if __SIZEOF_SIZE_T__ == 8
     : __first_{__v}
 #elif __SIZEOF_SIZE_T__ == 4
-    : __first_{__v, __v >> __bits_per_word}
+    : __first_{static_cast<__storage_type>(__v), static_cast<__storage_type>(__v >> __bits_per_word)}
 #else
 #error This constructor has not been ported to this platform
 #endif