diff --git a/stl/inc/xutility b/stl/inc/xutility
index 8d397a10972..51588356f7b 100644
--- a/stl/inc/xutility
+++ b/stl/inc/xutility
@@ -21,7 +21,7 @@ _STL_DISABLE_CLANG_WARNINGS
 #pragma push_macro("new")
 #undef new
 
-#if (defined(_M_IX86) || defined(_M_X64)) && !defined(_M_CEE_PURE) && !defined(_M_HYBRID) && !defined(_M_ARM64EC)
+#if (defined(_M_IX86) || defined(_M_X64)) && !defined(_M_CEE_PURE) && !defined(_M_HYBRID)
 #ifndef _USE_STD_VECTOR_ALGORITHMS
 #define _USE_STD_VECTOR_ALGORITHMS 1
 #endif // _USE_STD_VECTOR_ALGORITHMS
diff --git a/stl/src/vector_algorithms.cpp b/stl/src/vector_algorithms.cpp
index 88a5e5649f9..e0de355b2a9 100644
--- a/stl/src/vector_algorithms.cpp
+++ b/stl/src/vector_algorithms.cpp
@@ -10,11 +10,15 @@
 #error _M_CEE_PURE should not be defined when compiling vector_algorithms.cpp.
 #endif
 
-#if (defined(_M_IX86) || defined(_M_X64)) && !defined(_M_ARM64EC)
+#if defined(_M_IX86) || defined(_M_X64)
 
+#if defined(_M_ARM64EC)
+#include <intrin.h>
+#else // defined(_M_ARM64EC)
 #include <emmintrin.h>
 #include <immintrin.h>
 #include <intrin0.h>
+#endif // defined(_M_ARM64EC)
 #include <isa_availability.h>
 
 extern "C" long __isa_enabled;
@@ -50,6 +54,7 @@ static void _Advance_bytes(const void*& _Target, ptrdiff_t _Offset) noexcept {
 extern "C" {
 __declspec(noalias) void __cdecl __std_swap_ranges_trivially_swappable_noalias(
     void* _First1, void* _Last1, void* _First2) noexcept {
+#if !defined(_M_ARM64EC)
     constexpr size_t _Mask_32 = ~((static_cast<size_t>(1) << 5) - 1);
     if (_Byte_length(_First1, _Last1) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const void* _Stop_at = _First1;
@@ -63,6 +68,7 @@ __declspec(noalias) void __cdecl __std_swap_ranges_trivially_swappable_noalias(
             _Advance_bytes(_First2, 32);
         } while (_First1 != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     constexpr size_t _Mask_16 = ~((static_cast<size_t>(1) << 4) - 1);
     if (_Byte_length(_First1, _Last1) >= 16
@@ -131,6 +137,7 @@ void* __cdecl __std_swap_ranges_trivially_swappable(void* _First1, void* _Last1,
 }
 
 __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_1(void* _First, void* _Last) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 64 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const __m256i _Reverse_char_lanes_avx = _mm256_set_epi8( //
             0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, //
@@ -150,6 +157,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_1(void* _Firs
             _Advance_bytes(_First, 32);
         } while (_First != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_SSE42)) {
         const __m128i _Reverse_char_sse = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
@@ -171,6 +179,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_1(void* _Firs
 }
 
 __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_2(void* _First, void* _Last) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 64 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const __m256i _Reverse_short_lanes_avx = _mm256_set_epi8( //
             1, 0, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 15, 14, //
@@ -188,6 +197,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_2(void* _Firs
             _Advance_bytes(_First, 32);
         } while (_First != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_SSE42)) {
         const __m128i _Reverse_short_sse = _mm_set_epi8(1, 0, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 15, 14);
@@ -209,6 +219,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_2(void* _Firs
 }
 
 __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_4(void* _First, void* _Last) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 64 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const void* _Stop_at = _First;
         _Advance_bytes(_Stop_at, _Byte_length(_First, _Last) >> 6 << 5);
@@ -223,6 +234,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_4(void* _Firs
             _Advance_bytes(_First, 32);
         } while (_First != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 32
 #ifdef _M_IX86
@@ -247,6 +259,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_4(void* _Firs
 }
 
 __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_8(void* _First, void* _Last) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 64 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const void* _Stop_at = _First;
         _Advance_bytes(_Stop_at, _Byte_length(_First, _Last) >> 6 << 5);
@@ -261,6 +274,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_8(void* _Firs
             _Advance_bytes(_First, 32);
         } while (_First != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 32
 #ifdef _M_IX86
@@ -286,6 +300,7 @@ __declspec(noalias) void __cdecl __std_reverse_trivially_swappable_8(void* _Firs
 
 __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_1(
     const void* _First, const void* _Last, void* _Dest) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const __m256i _Reverse_char_lanes_avx = _mm256_set_epi8( //
             0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, //
@@ -300,6 +315,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_1(
             _Advance_bytes(_Dest, 32);
         } while (_Dest != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 16 && _bittest(&__isa_enabled, __ISA_AVAILABLE_SSE42)) {
         const __m128i _Reverse_char_sse = _mm_set_epi8(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15);
@@ -320,6 +336,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_1(
 
 __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_2(
     const void* _First, const void* _Last, void* _Dest) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const __m256i _Reverse_short_lanes_avx = _mm256_set_epi8( //
             1, 0, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 15, 14, //
@@ -334,6 +351,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_2(
             _Advance_bytes(_Dest, 32);
         } while (_Dest != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 16 && _bittest(&__isa_enabled, __ISA_AVAILABLE_SSE42)) {
         const __m128i _Reverse_short_sse = _mm_set_epi8(1, 0, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 15, 14);
@@ -354,6 +372,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_2(
 
 __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_4(
     const void* _First, const void* _Last, void* _Dest) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const void* _Stop_at = _Dest;
         _Advance_bytes(_Stop_at, _Byte_length(_First, _Last) >> 5 << 5);
@@ -365,6 +384,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_4(
             _Advance_bytes(_Dest, 32);
         } while (_Dest != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 16
 #ifdef _M_IX86
@@ -388,6 +408,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_4(
 
 __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_8(
     const void* _First, const void* _Last, void* _Dest) noexcept {
+#if !defined(_M_ARM64EC)
     if (_Byte_length(_First, _Last) >= 32 && _bittest(&__isa_enabled, __ISA_AVAILABLE_AVX2)) {
         const void* _Stop_at = _Dest;
         _Advance_bytes(_Stop_at, _Byte_length(_First, _Last) >> 5 << 5);
@@ -399,6 +420,7 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_8(
             _Advance_bytes(_Dest, 32);
         } while (_Dest != _Stop_at);
     }
+#endif // !defined(_M_ARM64EC)
 
     if (_Byte_length(_First, _Last) >= 16
 #ifdef _M_IX86
@@ -423,4 +445,4 @@ __declspec(noalias) void __cdecl __std_reverse_copy_trivially_copyable_8(
 
 } // extern "C"
 
-#endif // (defined(_M_IX86) || defined(_M_X64)) && !defined(_M_ARM64EC)
+#endif // defined(_M_IX86) || defined(_M_X64)