diff --git a/stl/inc/algorithm b/stl/inc/algorithm
index ce0a039bb16..312e06b0a00 100644
--- a/stl/inc/algorithm
+++ b/stl/inc/algorithm
@@ -638,7 +638,7 @@ _NODISCARD pair<_FwdIt1, _FwdIt2> mismatch(
 
 #ifdef __cpp_lib_concepts
 namespace ranges {
-    template <input_iterator _It1, input_iterator _It2, integral _Size, class _Pr, class _Pj1, class _Pj2>
+    template <input_iterator _It1, input_iterator _It2, _Integer_like _Size, class _Pr, class _Pj1, class _Pj2>
         requires indirectly_comparable<_It1, _It2, _Pr, _Pj1, _Pj2>
     _NODISCARD constexpr bool _Equal_count(
         _It1 _First1, _It2 _First2, _Size _Count, _Pr _Pred, _Pj1 _Proj1, _Pj2 _Proj2) {
@@ -6923,9 +6923,7 @@ namespace ranges {
             const auto _Count = _RANGES distance(_Range);
             auto _UResult =
                 _RANGES _Lower_bound_unchecked(_Ubegin(_Range), _Count, _Val, _Pass_fn(_Pred), _Pass_fn(_Proj));
-            auto _Result = _RANGES begin(_Range);
-            _Seek_wrapped(_Result, _STD move(_UResult));
-            return _Result;
+            return _Rewrap_iterator(_Range, _STD move(_UResult));
         }
     };
 
@@ -6978,9 +6976,7 @@ namespace ranges {
             const auto _Count = _RANGES distance(_Range);
             auto _UResult =
                 _RANGES _Upper_bound_unchecked(_Ubegin(_Range), _Count, _Val, _Pass_fn(_Pred), _Pass_fn(_Proj));
-            auto _Result = _RANGES begin(_Range);
-            _Seek_wrapped(_Result, _STD move(_UResult));
-            return _Result;
+            return _Rewrap_iterator(_Range, _STD move(_UResult));
         }
     };
 
@@ -9924,13 +9920,10 @@ namespace ranges {
             indirect_strict_weak_order<projected<iterator_t<_Rng>, _Pj>> _Pr = ranges::less>
         _NODISCARD constexpr minmax_element_result<borrowed_iterator_t<_Rng>> operator()(
             _Rng&& _Range, _Pr _Pred = {}, _Pj _Proj = {}) const {
-            auto _First   = _RANGES begin(_Range);
-            auto _UResult = _Minmax_element_fwd_unchecked(_RANGES _Unwrap_range_iter<_Rng>(_STD move(_First)),
-                _RANGES _Uend(_Range), _STD _Pass_fn(_Pred), _STD _Pass_fn(_Proj));
-            _STD _Seek_wrapped(_First, _STD move(_UResult.min));
-            auto _Second = _First;
-            _STD _Seek_wrapped(_Second, _STD move(_UResult.max));
-            return {_STD move(_First), _STD move(_Second)};
+            auto _UResult = _Minmax_element_fwd_unchecked(
+                _RANGES _Ubegin(_Range), _RANGES _Uend(_Range), _STD _Pass_fn(_Pred), _STD _Pass_fn(_Proj));
+            return {
+                _Rewrap_iterator(_Range, _STD move(_UResult.min)), _Rewrap_iterator(_Range, _STD move(_UResult.max))};
         }
 
     private:
@@ -10519,11 +10512,9 @@ namespace ranges {
         template <forward_range _Rng, class _Pj = identity,
             indirect_strict_weak_order<projected<iterator_t<_Rng>, _Pj>> _Pr = ranges::less>
         _NODISCARD constexpr borrowed_iterator_t<_Rng> operator()(_Rng&& _Range, _Pr _Pred = {}, _Pj _Proj = {}) const {
-            auto _First  = _RANGES begin(_Range);
-            auto _UFirst = _RANGES _Is_sorted_until_unchecked(
-                _Unwrap_range_iter<_Rng>(_First), _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
-            _Seek_wrapped(_First, _STD move(_UFirst));
-            return _First;
+            auto _UResult =
+                _RANGES _Is_sorted_until_unchecked(_Ubegin(_Range), _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
+            return _Rewrap_iterator(_Range, _STD move(_UResult));
         }
     };
 
diff --git a/stl/inc/ranges b/stl/inc/ranges
index 58351898000..cf7d9e016bd 100644
--- a/stl/inc/ranges
+++ b/stl/inc/ranges
@@ -6682,7 +6682,6 @@ namespace ranges {
                     }
 #endif // _ITERATOR_DEBUG_LEVEL != 0
 
-                    // Per to-be-filed LWG issue (See GH-2995)
                     if constexpr (sized_sentinel_for<_Base_sentinel, _Base_iterator>) {
                         _Missing = _RANGES advance(_Current, _Count * _Off, _End);
                     } else {
@@ -7642,7 +7641,6 @@ namespace ranges {
                     }
 #endif // _ITERATOR_DEBUG_LEVEL != 0
 
-                    // Per to-be-filed LWG issue (See GH-2995)
                     if constexpr (sized_sentinel_for<_Base_sentinel, _Base_iterator>) {
                         _Missing = _RANGES advance(_Current, _Stride * _Off, _End);
                     } else {
diff --git a/stl/inc/regex b/stl/inc/regex
index aa1974d47e1..05cb7465d3b 100644
--- a/stl/inc/regex
+++ b/stl/inc/regex
@@ -58,7 +58,7 @@ _STL_DISABLE_CLANG_WARNINGS
 
 _STD_BEGIN
 
-enum _Meta_type { // meta character representations for parser
+enum _Meta_type : int { // meta character representations for parser
     _Meta_lpar  = '(',
     _Meta_rpar  = ')',
     _Meta_dlr   = '$',
diff --git a/stl/inc/sstream b/stl/inc/sstream
index 365753b94e0..12a90ae5651 100644
--- a/stl/inc/sstream
+++ b/stl/inc/sstream
@@ -67,12 +67,12 @@ public:
         const basic_string<_Elem, _Traits, _Alloc2>& _Str, ios_base::openmode _Mode = ios_base::in | ios_base::out)
         : basic_stringbuf(_Str, _Mode, _Alloc{}) {}
 
-    basic_stringbuf(basic_stringbuf&& _Right, const _Alloc& _Al_) : _Al(_Al_) {
+    basic_stringbuf(basic_stringbuf&& _Right, const _Alloc& _Al_) : _Mystate(0), _Al(_Al_) {
         _Assign_rv(_STD move(_Right));
     }
 #endif // _HAS_CXX20
 
-    basic_stringbuf(basic_stringbuf&& _Right) {
+    basic_stringbuf(basic_stringbuf&& _Right) : _Mystate(0) {
         _Assign_rv(_STD move(_Right));
     }
 
@@ -269,7 +269,7 @@ protected:
 
         _Mysb::setp(_Newptr, _New_pnext, _Newptr + _Newsize);
         if (_Mystate & _Noread) { // maintain eback() == allocated pointer invariant
-            _Mysb::setg(_Newptr, nullptr, _Newptr);
+            _Mysb::setg(_Newptr, _Newptr, _Newptr);
         } else { // if readable, set the get area to initialized region
             _Mysb::setg(_Newptr, _Newptr + (_Mysb::gptr() - _Oldptr), _Seekhigh);
         }
@@ -328,6 +328,12 @@ protected:
 
     pos_type seekoff(
         off_type _Off, ios_base::seekdir _Way, ios_base::openmode _Mode = ios_base::in | ios_base::out) override {
+        const bool _Need_read_but_cannot  = (_Mode & ios_base::in) != 0 && (_Mystate & _Noread) != 0;
+        const bool _Need_write_but_cannot = (_Mode & ios_base::out) != 0 && (_Mystate & _Constant) != 0;
+        if (_Need_read_but_cannot || _Need_write_but_cannot) {
+            return pos_type{off_type{-1}};
+        }
+
         // change position by _Off, according to _Way, _Mode
         const auto _Gptr_old = _Mysb::gptr();
         const auto _Pptr_old = (_Mystate & _Constant) ? nullptr : _Mysb::pptr();
@@ -388,6 +394,12 @@ protected:
     }
 
     pos_type seekpos(pos_type _Pos, ios_base::openmode _Mode = ios_base::in | ios_base::out) override {
+        const bool _Need_read_but_cannot  = (_Mode & ios_base::in) != 0 && (_Mystate & _Noread) != 0;
+        const bool _Need_write_but_cannot = (_Mode & ios_base::out) != 0 && (_Mystate & _Constant) != 0;
+        if (_Need_read_but_cannot || _Need_write_but_cannot) {
+            return pos_type{off_type{-1}};
+        }
+
         // change position to _Pos, according to _Mode
         const auto _Off      = static_cast<streamoff>(_Pos);
         const auto _Gptr_old = _Mysb::gptr();
@@ -440,7 +452,7 @@ protected:
                 _Mysb::setp(_Pnew, (_State & (_Atend | _Append)) ? _Seekhigh : _Pnew, _Seekhigh);
 
                 if (_State & _Noread) { // maintain "_Allocated == eback() points to buffer base" invariant
-                    _Mysb::setg(_Pnew, nullptr, _Pnew);
+                    _Mysb::setg(_Pnew, _Pnew, _Pnew);
                 }
             }
 
@@ -469,7 +481,7 @@ protected:
 
         _Mysb::setp(_Pnew, _Next, _End_buffer);
         if (_State & _Noread) { // maintain "_Allocated == eback() points to buffer base" invariant
-            _Mysb::setg(_Pnew, nullptr, _Pnew);
+            _Mysb::setg(_Pnew, _Pnew, _Pnew);
         } else {
             _Mysb::setg(_Pnew, _Pnew, _Seekhigh);
         }
diff --git a/stl/inc/xutility b/stl/inc/xutility
index d4b5112f2de..4353b17e043 100644
--- a/stl/inc/xutility
+++ b/stl/inc/xutility
@@ -6683,10 +6683,9 @@ namespace ranges {
         template <forward_range _Rng, class _Pj = identity,
             indirect_strict_weak_order<projected<iterator_t<_Rng>, _Pj>> _Pr = ranges::less>
         _NODISCARD constexpr borrowed_iterator_t<_Rng> operator()(_Rng&& _Range, _Pr _Pred = {}, _Pj _Proj = {}) const {
-            auto _First = _RANGES begin(_Range);
-            _Seek_wrapped(_First, _RANGES _Max_element_unchecked(_Unwrap_range_iter<_Rng>(_STD move(_First)),
-                                      _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj)));
-            return _First;
+            auto _UResult =
+                _RANGES _Max_element_unchecked(_Ubegin(_Range), _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
+            return _Rewrap_iterator(_Range, _STD move(_UResult));
         }
     };
 
@@ -6878,10 +6877,9 @@ namespace ranges {
         template <forward_range _Rng, class _Pj = identity,
             indirect_strict_weak_order<projected<iterator_t<_Rng>, _Pj>> _Pr = ranges::less>
         _NODISCARD constexpr borrowed_iterator_t<_Rng> operator()(_Rng&& _Range, _Pr _Pred = {}, _Pj _Proj = {}) const {
-            auto _First = _RANGES begin(_Range);
-            _Seek_wrapped(_First, _RANGES _Min_element_unchecked(_Unwrap_range_iter<_Rng>(_STD move(_First)),
-                                      _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj)));
-            return _First;
+            auto _UResult =
+                _RANGES _Min_element_unchecked(_Ubegin(_Range), _Uend(_Range), _Pass_fn(_Pred), _Pass_fn(_Proj));
+            return _Rewrap_iterator(_Range, _STD move(_UResult));
         }
     };
 
diff --git a/tests/std/tests/P0896R4_istream_view/test.cpp b/tests/std/tests/P0896R4_istream_view/test.cpp
index db9a35a1d01..d007d86c838 100644
--- a/tests/std/tests/P0896R4_istream_view/test.cpp
+++ b/tests/std/tests/P0896R4_istream_view/test.cpp
@@ -119,6 +119,23 @@ void test_one_type() {
         static_assert(noexcept(views::istream<T>(wintstream)));
         assert(ranges::equal(input, expected_vals));
     }
+#if _HAS_CXX23
+    { // Using ranges::istream_view with const iterators
+        istringstream intstream{"0 1 2 3"};
+        T input[] = {-1, -1, -1, -1, -1};
+        ranges::istream_view<T> v(intstream);
+        ranges::copy(v.cbegin(), v.cend(), input);
+        assert(ranges::equal(input, expected_vals));
+    }
+
+    { // Using ranges::wistream_view with const iterators
+        wistringstream wintstream{L"0 1 2 3"};
+        T input[] = {-1, -1, -1, -1, -1};
+        ranges::wistream_view<T> v(wintstream);
+        ranges::copy(v.cbegin(), v.cend(), input);
+        assert(ranges::equal(input, expected_vals));
+    }
+#endif // _HAS_CXX23
 }
 
 istringstream some_stream{"42"};
diff --git a/tests/std/tests/P0896R4_ranges_alg_equal/test.cpp b/tests/std/tests/P0896R4_ranges_alg_equal/test.cpp
index 7a85024c423..3b3487887e6 100644
--- a/tests/std/tests/P0896R4_ranges_alg_equal/test.cpp
+++ b/tests/std/tests/P0896R4_ranges_alg_equal/test.cpp
@@ -79,6 +79,13 @@ constexpr void smoke_test() {
         assert(!equal(begin(arr1), unreachable_sentinel, begin(arr2), end(arr2)));
         assert(!equal(begin(arr1), end(arr1), begin(arr2), unreachable_sentinel));
     }
+#ifndef _M_CEE // TRANSITION, VSO-1666180
+    {
+        // Validate GH-3550: "<ranges>: ranges::equal does not work for ranges with integer-class range_difference_t"
+        auto v = ranges::subrange{std::views::iota(0ull, 10ull)} | std::views::drop(2);
+        assert(equal(v, v));
+    }
+#endif // _M_CEE
 }
 
 int main() {
diff --git a/tests/std/tests/P0896R4_views_empty/test.cpp b/tests/std/tests/P0896R4_views_empty/test.cpp
index 5f6a2338b79..252fb5141ec 100644
--- a/tests/std/tests/P0896R4_views_empty/test.cpp
+++ b/tests/std/tests/P0896R4_views_empty/test.cpp
@@ -20,7 +20,7 @@ constexpr bool test_one_type() {
     static_assert(ranges::view<R> && ranges::contiguous_range<R> && ranges::sized_range<R> && ranges::common_range<R>);
     static_assert(ranges::borrowed_range<R>);
     static_assert(same_as<const R, decltype(views::empty<T>)>);
-    auto& r = views::empty<T>;
+    constexpr auto& r = views::empty<T>;
 
     // validate member size
     static_assert(same_as<decltype(R::size()), size_t>);
@@ -50,7 +50,16 @@ constexpr bool test_one_type() {
     static_assert(noexcept(R::empty()));
     static_assert(noexcept(ranges::empty(r)));
 
-    // validate members inherited from view_interface
+#if _HAS_CXX23
+    // validate members cbegin and cend inherited from view_interface
+    static_assert(same_as<decltype(r.cbegin()), const_iterator<T*>>);
+    static_assert(r.cbegin() == nullptr);
+
+    static_assert(same_as<decltype(r.cend()), const_iterator<T*>>);
+    static_assert(r.cend() == nullptr);
+#endif // _HAS_CXX23
+
+    // validate other members inherited from view_interface
     assert(!r);
 
     return true;
diff --git a/tests/std/tests/P0896R4_views_iota/test.cpp b/tests/std/tests/P0896R4_views_iota/test.cpp
index a0fee3aff06..a4e530846fc 100644
--- a/tests/std/tests/P0896R4_views_iota/test.cpp
+++ b/tests/std/tests/P0896R4_views_iota/test.cpp
@@ -197,6 +197,14 @@ constexpr void test_integral() {
         static_assert(noexcept(first != last)); // strengthened
         assert(last - first == 8);
         static_assert(noexcept(last - first)); // strengthened
+
+#if _HAS_CXX23
+        const same_as<ranges::const_iterator_t<R>> auto cfirst = rng.cbegin();
+        assert(cfirst == first);
+        const same_as<ranges::const_sentinel_t<R>> auto clast = rng.cend();
+        assert(clast == last);
+        assert(clast - cfirst == 8);
+#endif // _HAS_CXX23
     }
 
     {
@@ -234,6 +242,21 @@ constexpr void test_integral() {
         }
 
         static_assert(!CanSize<ranges::iota_view<T>>);
+
+#if _HAS_CXX23
+        {
+            const same_as<R> auto rng = views::iota(low);
+            const ranges::subrange crng{rng.cbegin(), rng.cend()};
+
+            auto i = low;
+            for (const auto& e : crng) {
+                assert(e == i);
+                if (++i == high) {
+                    break;
+                }
+            }
+        }
+#endif // _HAS_CXX23
     }
 }
 
diff --git a/tests/std/tests/P0896R4_views_single/test.cpp b/tests/std/tests/P0896R4_views_single/test.cpp
index 18149b0566d..54fc7abfb7c 100644
--- a/tests/std/tests/P0896R4_views_single/test.cpp
+++ b/tests/std/tests/P0896R4_views_single/test.cpp
@@ -94,6 +94,23 @@ constexpr bool test_one_type(T value, Args&&... args) {
     static_assert(noexcept(cr0.end()));
     static_assert(noexcept(ranges::end(cr0)));
 
+#if _HAS_CXX23
+    // validate members cbegin and cend
+    static_assert(same_as<decltype(r0.cbegin()), const T*>);
+    assert(*r0.cbegin() == value);
+    assert(r0.cbegin() == ptr);
+
+    static_assert(same_as<decltype(r0.cend()), const T*>);
+    assert(r0.cend() == ptr + 1);
+
+    static_assert(same_as<decltype(cr0.cbegin()), const T*>);
+    assert(*cr0.cbegin() == value);
+    assert(cr0.cbegin() == cptr);
+
+    static_assert(same_as<decltype(cr0.cend()), const T*>);
+    assert(cr0.cend() == cptr + 1);
+#endif // _HAS_CXX23
+
     // validate CTAD and T&& constructor
     const same_as<R> auto cr1 = ranges::single_view{move(value)};
     assert(cr1.data() != nullptr);
diff --git a/tests/std/tests/P2474R2_views_repeat/test.cpp b/tests/std/tests/P2474R2_views_repeat/test.cpp
index 4c360593b13..ba1f542495f 100644
--- a/tests/std/tests/P2474R2_views_repeat/test.cpp
+++ b/tests/std/tests/P2474R2_views_repeat/test.cpp
@@ -252,6 +252,16 @@ constexpr void test_common(T val, B bound = unreachable_sentinel) {
         assert(cmp_equal(last - first, rng.size()));
         static_assert(noexcept(last - first)); // strengthened
     }
+
+    const same_as<ranges::const_iterator_t<R>> auto cfirst = rng.cbegin();
+    assert(cfirst == first);
+    const same_as<ranges::const_sentinel_t<R>> auto clast = rng.cend();
+    if constexpr (ranges::common_range<R>) {
+        assert(clast == last);
+        assert(cmp_equal(clast - cfirst, rng.size()));
+    } else {
+        static_assert(same_as<remove_const_t<decltype(clast)>, unreachable_sentinel_t>);
+    }
 }
 
 struct move_tester {
diff --git a/tests/std/tests/char8_t_17_matrix.lst b/tests/std/tests/char8_t_17_matrix.lst
index 97170842230..cfabb7ae85e 100644
--- a/tests/std/tests/char8_t_17_matrix.lst
+++ b/tests/std/tests/char8_t_17_matrix.lst
@@ -35,3 +35,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/char8_t_impure_matrix.lst b/tests/std/tests/char8_t_impure_matrix.lst
index d5a87b4e2c3..f7c9462651c 100644
--- a/tests/std/tests/char8_t_impure_matrix.lst
+++ b/tests/std/tests/char8_t_impure_matrix.lst
@@ -37,3 +37,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/char8_t_matrix.lst b/tests/std/tests/char8_t_matrix.lst
index 12d002c7609..7795932f132 100644
--- a/tests/std/tests/char8_t_matrix.lst
+++ b/tests/std/tests/char8_t_matrix.lst
@@ -36,3 +36,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17 /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive- /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/concepts_20_matrix.lst b/tests/std/tests/concepts_20_matrix.lst
index 7ce5f2b0e0c..ea8806b97bb 100644
--- a/tests/std/tests/concepts_20_matrix.lst
+++ b/tests/std/tests/concepts_20_matrix.lst
@@ -27,3 +27,4 @@ PM_CL="/clr /MDd /std:c++20"
 # PM_CL="/std:c++latest /permissive- /BE /c /EHsc /MTd"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++20 /permissive- /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /permissive- /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /permissive- /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/concepts_latest_matrix.lst b/tests/std/tests/concepts_latest_matrix.lst
index 73625bbbb86..ecf410ca036 100644
--- a/tests/std/tests/concepts_latest_matrix.lst
+++ b/tests/std/tests/concepts_latest_matrix.lst
@@ -22,3 +22,4 @@ PM_CL="/MTd /D_ITERATOR_DEBUG_LEVEL=2 /permissive- /analyze:only /analyze:autolo
 # PM_CL="/permissive- /BE /c /MTd"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/impure_matrix.lst b/tests/std/tests/impure_matrix.lst
index 53e8bf46f1c..a14eb162d57 100644
--- a/tests/std/tests/impure_matrix.lst
+++ b/tests/std/tests/impure_matrix.lst
@@ -35,3 +35,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/locale0_implib_cpp_matrix.lst b/tests/std/tests/locale0_implib_cpp_matrix.lst
index 32992138ddc..73891267e7c 100644
--- a/tests/std/tests/locale0_implib_cpp_matrix.lst
+++ b/tests/std/tests/locale0_implib_cpp_matrix.lst
@@ -37,3 +37,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17 /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive- /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/strict_concepts_20_matrix.lst b/tests/std/tests/strict_concepts_20_matrix.lst
index e8dd503d44f..cc86671e318 100644
--- a/tests/std/tests/strict_concepts_20_matrix.lst
+++ b/tests/std/tests/strict_concepts_20_matrix.lst
@@ -26,3 +26,4 @@ PM_CL="/clr /MDd /std:c++20"
 # PM_CL="/std:c++latest /BE /c /EHsc /MTd"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++20 /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/strict_concepts_latest_matrix.lst b/tests/std/tests/strict_concepts_latest_matrix.lst
index 3b126ab4c16..2604c0e479c 100644
--- a/tests/std/tests/strict_concepts_latest_matrix.lst
+++ b/tests/std/tests/strict_concepts_latest_matrix.lst
@@ -24,3 +24,4 @@ PM_CL="/MTd /D_ITERATOR_DEBUG_LEVEL=2 /analyze:only /analyze:autolog-"
 # PM_CL="/BE /c /MTd"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/usual_17_matrix.lst b/tests/std/tests/usual_17_matrix.lst
index 510cc46a999..6b82f8ba838 100644
--- a/tests/std/tests/usual_17_matrix.lst
+++ b/tests/std/tests/usual_17_matrix.lst
@@ -34,3 +34,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/usual_20_matrix.lst b/tests/std/tests/usual_20_matrix.lst
index c8aa8e8da23..119e24c2246 100644
--- a/tests/std/tests/usual_20_matrix.lst
+++ b/tests/std/tests/usual_20_matrix.lst
@@ -24,3 +24,4 @@ PM_CL="/BE /c /EHsc /MD /std:c++20 /permissive-"
 PM_CL="/BE /c /EHsc /MTd /std:c++latest /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++20 /permissive- /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /permissive- /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /std:c++latest /permissive- /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/usual_latest_matrix.lst b/tests/std/tests/usual_latest_matrix.lst
index 0f50c36029c..68e6e2fbcae 100644
--- a/tests/std/tests/usual_latest_matrix.lst
+++ b/tests/std/tests/usual_latest_matrix.lst
@@ -22,3 +22,4 @@ PM_CL="/BE /c /MD /permissive-"
 PM_CL="/BE /c /MTd /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MD"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MTd /fp:strict"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /permissive- /MT /fp:strict -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/std/tests/usual_matrix.lst b/tests/std/tests/usual_matrix.lst
index bde343a864b..ecf7265160b 100644
--- a/tests/std/tests/usual_matrix.lst
+++ b/tests/std/tests/usual_matrix.lst
@@ -36,3 +36,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MDd /std:c++17 /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++20 /permissive- /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MTd /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call /EHsc /MT /std:c++latest /permissive- /fp:strict /w14640 /Zc:threadSafeInit- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/tr1/env.lst b/tests/tr1/env.lst
index a6afa08fef3..a814774a4a5 100644
--- a/tests/tr1/env.lst
+++ b/tests/tr1/env.lst
@@ -31,3 +31,4 @@ PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsin
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MT /std:c++20 /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MTd /std:c++latest /permissive-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MT /std:c++latest /permissive- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/tr1/env_minus_md_idl.lst b/tests/tr1/env_minus_md_idl.lst
index d9f860c1dbf..2fc8c1b4a5d 100644
--- a/tests/tr1/env_minus_md_idl.lst
+++ b/tests/tr1/env_minus_md_idl.lst
@@ -26,3 +26,4 @@ PM_CL="/BE /c /EHsc /MTd /std:c++latest /permissive- /w14640 /Zc:threadSafeInit-
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MD /std:c++14 /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MDd /std:c++17 /w14640 /Zc:threadSafeInit-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MTd /std:c++latest /permissive- /w14640 /Zc:threadSafeInit-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MT /std:c++latest /permissive- /w14640 /Zc:threadSafeInit- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/tr1/env_minus_pure.lst b/tests/tr1/env_minus_pure.lst
index fee56896524..72ffa04557e 100644
--- a/tests/tr1/env_minus_pure.lst
+++ b/tests/tr1/env_minus_pure.lst
@@ -27,3 +27,4 @@ PM_CL="/BE /c /EHsc /MTd /std:c++latest /permissive-"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MD /std:c++14"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MDd /std:c++17"
 PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MTd /std:c++latest /permissive-"
+PM_COMPILER="clang-cl" PM_CL="-fno-ms-compatibility -fno-delayed-template-parsing -Wno-unqualified-std-cast-call -Wno-deprecated-declarations -Wno-self-assign /EHsc /MT /std:c++latest /permissive- -fsanitize=undefined -fno-sanitize-recover=undefined"
diff --git a/tests/tr1/tests/chrono/test.cpp b/tests/tr1/tests/chrono/test.cpp
index d02fa73132b..635a66a4be0 100644
--- a/tests/tr1/tests/chrono/test.cpp
+++ b/tests/tr1/tests/chrono/test.cpp
@@ -53,9 +53,9 @@ namespace {
         CHECK_INT(d_i::max(), STD numeric_limits<int>::max());
 
         typedef STD chrono::duration_values<double> d_d;
-        CHECK_INT(d_d::zero(), 0.0);
-        CHECK_INT(d_d::min(), STD numeric_limits<double>::lowest());
-        CHECK_INT(d_d::max(), STD numeric_limits<double>::max());
+        CHECK_DOUBLE(d_d::zero(), 0.0);
+        CHECK_DOUBLE(d_d::min(), STD numeric_limits<double>::lowest());
+        CHECK_DOUBLE(d_d::max(), STD numeric_limits<double>::max());
     }
 
     template <class Rep, class Period>
diff --git a/tests/tr1/tests/cstddef/test.cpp b/tests/tr1/tests/cstddef/test.cpp
index c8731270d76..e0d4c158f69 100644
--- a/tests/tr1/tests/cstddef/test.cpp
+++ b/tests/tr1/tests/cstddef/test.cpp
@@ -20,16 +20,14 @@ typedef struct {
 } Str;
 
 void test_cpp() { // test C++ header
-    ptrdiff_t zero                  = 0;
-    static char* pc                 = (char*) zero;
     static const STDx size_t offs[] = {offsetof(Str, f1), offsetof(Str, f2), offsetof(Str, f3)};
-    STDx ptrdiff_t pdiff            = &pc[INT_MAX] - &pc[0];
+    STDx ptrdiff_t pdiff            = &offs[2] - &offs[0];
     wchar_t wc                      = L'Z';
     Str x                           = {1, {2}, 3};
     char* ps                        = (char*) &x;
 
     CHECK_INT(sizeof(STDx size_t), sizeof(sizeof(char)));
-    CHECK_INT(pdiff, &pc[INT_MAX] - &pc[0]);
+    CHECK_INT(pdiff, &offs[2] - &offs[0]);
     CHECK_INT(wc, L'Z');
     CHECK(offs[0] < offs[1]);
     CHECK_INT((long) *(float*) (ps + offs[1]), 2);
diff --git a/tests/tr1/tests/streambuf1/test.cpp b/tests/tr1/tests/streambuf1/test.cpp
index ea455177770..78dedcea08e 100644
--- a/tests/tr1/tests/streambuf1/test.cpp
+++ b/tests/tr1/tests/streambuf1/test.cpp
@@ -28,7 +28,7 @@ class Mybuf : public STD streambuf {
     }
 
     void setp(char* p) { // set pptr
-        Mybase::setp(p, nullptr);
+        Mybase::setp(p, p);
     }
 
     char* getp() const { // get pptr
diff --git a/tests/tr1/tests/streambuf2/test.cpp b/tests/tr1/tests/streambuf2/test.cpp
index 12d7202f466..991adeca90f 100644
--- a/tests/tr1/tests/streambuf2/test.cpp
+++ b/tests/tr1/tests/streambuf2/test.cpp
@@ -29,7 +29,7 @@ class Mybuf : public STD wstreambuf {
     }
 
     void setp(wchar_t* p) { // set pptr
-        Mybase::setp(p, nullptr);
+        Mybase::setp(p, p);
     }
 
     wchar_t* getp() const { // get pptr
diff --git a/tests/tr1/tests/type_traits5/test.cpp b/tests/tr1/tests/type_traits5/test.cpp
index 9cdf0005555..e0ef94e1d3d 100644
--- a/tests/tr1/tests/type_traits5/test.cpp
+++ b/tests/tr1/tests/type_traits5/test.cpp
@@ -180,7 +180,7 @@ static void t_add_rvalue_reference() { // test add_rvalue_reference<T> for vario
     CHECK_TYPEX(STD add_rvalue_reference<ARR1>::type, ARR1 &&);
 }
 
-typedef enum { red, blue, green } color;
+enum color : int { red, blue, green };
 
 static void t_make_signed() { // test make_signed<T> for various types
     CHECK_TYPE(STD make_signed<signed char>::type, signed char);
diff --git a/tests/utils/stl/test/features.py b/tests/utils/stl/test/features.py
index abfa20bbc62..5a8adf8e64c 100644
--- a/tests/utils/stl/test/features.py
+++ b/tests/utils/stl/test/features.py
@@ -49,6 +49,7 @@ def getDefaultFeatures(config, litConfig):
         DEFAULT_FEATURES.append(Feature(name='x86'))
 
     elif litConfig.target_arch.casefold() == 'x64'.casefold():
+        DEFAULT_FEATURES.append(Feature(name='ubsan'))
         DEFAULT_FEATURES.append(Feature(name='edg'))
         DEFAULT_FEATURES.append(Feature(name='arch_avx2'))
         DEFAULT_FEATURES.append(Feature(name='x64'))
diff --git a/tests/utils/stl/test/tests.py b/tests/utils/stl/test/tests.py
index 09fdeb86fc2..5d10ae30386 100644
--- a/tests/utils/stl/test/tests.py
+++ b/tests/utils/stl/test/tests.py
@@ -249,8 +249,10 @@ def _parseFlags(self, litConfig):
                 self.requires.append('clr_pure') # TRANSITION, GH-798
             elif flag[1:] == 'clr':
                 self.requires.append('clr') # TRANSITION, GH-797
+            elif flag[1:] == 'fsanitize=undefined':
+                self.requires.append('ubsan') # available for x64, see features.py
             elif flag[1:] == 'BE':
-                self.requires.append('edg') # available for x86, see features.py
+                self.requires.append('edg') # available for x64, see features.py
             elif flag[1:] == 'arch:AVX2':
                 self.requires.append('arch_avx2') # available for x86 and x64, see features.py
             elif flag[1:] == 'arch:IA32':