libstdc++: Simplify basic_string_view::ends_with [PR 101361]

The use of npos triggers a diagnostic as described in PR c++/101361.
This change replaces the use of npos with the exact length, which is
already known. We can further simplify it by inlining the effects of
compare and substr, avoiding the redundant range checks in the latter.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:

	PR c++/101361
	* include/std/string_view (ends_with): Use traits_type::compare
	directly.

(cherry picked from commit 4d3eaeb4f505b0838c673ee28e7dba8687fc8272)

diff --git a/libstdc++-v3/include/std/string_view b/libstdc++-v3/include/std/string_view
index cfdcf28f0261869631b21c8e238a93b5ce08f2da..4ea72c6cef23c0d94b87c2bad9b219d903247cb2 100644 (file)
--- a/libstdc++-v3/include/std/string_view
+++ b/libstdc++-v3/include/std/string_view
@@ -361,8 +361,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr bool
       ends_with(basic_string_view __x) const noexcept
       {
-       return this->size() >= __x.size()
-           && this->compare(this->size() - __x.size(), npos, __x) == 0;
+       const auto __len = this->size();
+       const auto __xlen = __x.size();
+       return __len >= __xlen
+         && traits_type::compare(end() - __xlen, __x.data(), __xlen) == 0;
       }
 
       constexpr bool