libstdc++: Fix zip_view's operator- for integer-class difference type [PR106766]

The difference type of an underlying iterator could be an integer-class
type, which make_unsigned_t doesn't handle, so we need to use the more
general __make_unsigned_like_t / __to_unsigned_like here instead.

	PR libstdc++/106766

libstdc++-v3/ChangeLog:

	* include/std/ranges (zip_view::_Iterator::operator-): Use
	__to_unsigned_like instead of make_unsigned_t.
	(zip_view::_Sentinel::operator-): Likewise.
	* testsuite/std/ranges/zip/1.cc (test04): New test.

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 2b5cb0531f02c96c45eaddf41dbe4242d7d90915..2b8fec3c386d3b9867ca37b862981437537a76f1 100644 (file)
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -4657,8 +4657,8 @@ namespace views::__adaptor
        return ranges::min({difference_type(std::get<_Is>(__x._M_current)
                                            - std::get<_Is>(__y._M_current))...},
                           ranges::less{},
-                          [](difference_type __i) -> make_unsigned_t<difference_type> {
-                            return __i < 0 ? -__i : __i;
+                          [](difference_type __i) {
+                            return __detail::__to_unsigned_like(__i < 0 ? -__i : __i);
                           });
       }(make_index_sequence<sizeof...(_Vs)>{});
     }
@@ -4726,8 +4726,8 @@ namespace views::__adaptor
       return [&]<size_t... _Is>(index_sequence<_Is...>) {
        return ranges::min({_Ret(std::get<_Is>(__x._M_current) - std::get<_Is>(__y._M_end))...},
                           ranges::less{},
-                          [](_Ret __i) -> make_unsigned_t<_Ret> {
-                            return __i < 0 ? -__i : __i;
+                          [](_Ret __i) {
+                            return __detail::__to_unsigned_like(__i < 0 ? -__i : __i);
                           });
       }(make_index_sequence<sizeof...(_Vs)>{});
     }

diff --git a/libstdc++-v3/testsuite/std/ranges/zip/1.cc b/libstdc++-v3/testsuite/std/ranges/zip/1.cc
index 0113efdb537ca4b4a47d73e3111c6bafbb62bb84..e9e40fb15eb7af850cdba526b2829bf7ad43f7d9 100644 (file)
--- a/libstdc++-v3/testsuite/std/ranges/zip/1.cc
+++ b/libstdc++-v3/testsuite/std/ranges/zip/1.cc
@@ -102,10 +102,28 @@ test03()
   return true;
 }
 
+constexpr bool
+test04()
+{
+  // PR libstdc++/106766
+#if __SIZEOF_INT128__
+  auto r = views::zip(views::iota(__int128(0), __int128(1)));
+#else
+  auto r = views::zip(views::iota(0ll, 1ll));
+#endif
+  auto i = r.begin();
+  auto s = r.end();
+  VERIFY( s - i == 1 );
+  VERIFY( i + 1 - i == 1 );
+
+  return true;
+}
+
 int
 main()
 {
   static_assert(test01());
   static_assert(test02());
   static_assert(test03());
+  static_assert(test04());
 }