diff --git a/.github/workflows/clang-cl.yml b/.github/workflows/clang-cl.yml
new file mode 100644
index 0000000..15dfbbb
--- /dev/null
+++ b/.github/workflows/clang-cl.yml
@@ -0,0 +1,38 @@
+name: Clang-CL
+
+permissions:
+  contents: read
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+env:
+  BUILD_TYPE: Release
+
+jobs:
+  build:
+    runs-on: windows-latest
+
+    steps:
+    - uses: actions/checkout@v4
+
+    - uses: ilammy/msvc-dev-cmd@v1
+
+    - name: Environment
+      run: clang-cl -E -Xclang -dM nul
+
+    - name: Configure CMake
+      env:
+        CC: clang-cl
+        CMAKE_GENERATOR: Ninja
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+
+    - name: Build
+      run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
+
+    - name: Test
+      working-directory: ${{github.workspace}}/build
+      run: ctest -C ${{env.BUILD_TYPE}} --output-on-failure -LE performance
diff --git a/Makefile b/Makefile
index f0dca46..c561f64 100644
--- a/Makefile
+++ b/Makefile
@@ -33,9 +33,10 @@ IMPL_SOURCES += src/hiaex4/HiAEx4_vaes_avx512.c
 ALL_SOURCES = $(MAIN_SOURCE) $(IMPL_SOURCES)
 
 # Header dependencies
-HIAE_HEADERS = include/HiAE.h src/hiae/HiAE_internal.h src/hiae/softaes.h
-HIAEX2_HEADERS = include/HiAEx2.h src/hiaex2/HiAEx2_internal.h src/hiaex2/softaes.h
-HIAEX4_HEADERS = include/HiAEx4.h src/hiaex4/HiAEx4_internal.h src/hiaex4/softaes.h
+COMMON_HEADERS = src/common/common.h src/common/cpu.h
+HIAE_HEADERS = include/HiAE.h src/hiae/HiAE_internal.h src/hiae/softaes.h $(COMMON_HEADERS)
+HIAEX2_HEADERS = include/HiAEx2.h src/hiaex2/HiAEx2_internal.h src/hiaex2/softaes.h $(COMMON_HEADERS)
+HIAEX4_HEADERS = include/HiAEx4.h src/hiaex4/HiAEx4_internal.h src/hiaex4/softaes.h $(COMMON_HEADERS)
 CLI_HEADERS = hiae-cli/src/platform.h hiae-cli/src/key_utils.h hiae-cli/src/file_ops.h
 TEST_HEADERS = test/timing.h
 
diff --git a/scripts/amalgamate.py b/scripts/amalgamate.py
index 364edaf..72b68d9 100755
--- a/scripts/amalgamate.py
+++ b/scripts/amalgamate.py
@@ -107,6 +107,8 @@ def remove_includes(content, implementation_file=None):
             # Keep system includes, remove local includes
             if ('"HiAE.h"' in include_file or 
                 '"HiAE_internal.h"' in include_file or
+                '"../common/common.h"' in include_file or
+                '"../common/cpu.h"' in include_file or
                 '"softaes.h"' in include_file):
                 continue
             # Keep all other includes (system headers, intrinsics, etc.)
@@ -307,6 +309,21 @@ def create_amalgamation():
         header_body = re.sub(r'#ifdef __cplusplus.*?#endif', '', header_body, flags=re.DOTALL)
         amalgamated_content += header_body
     
+    # Add shared capability-detection headers (src/common)
+    for common_name, guard in (("common.h", "hiae_common_H"), ("cpu.h", "hiae_cpu_H")):
+        common_header = read_file(repo_root / "src" / "common" / common_name)
+        if not common_header:
+            print(f"Failed to read src/common/{common_name}")
+            return False
+        common_content = re.search(r'#define ' + guard + r'\s*\n(.*?)#endif /\* ' + guard + r' \*/',
+                                   common_header, re.DOTALL)
+        if not common_content:
+            print(f"Failed to parse src/common/{common_name}")
+            return False
+        common_body = common_content.group(1)
+        common_body = re.sub(r'#include\s+"[^"]+"', '', common_body)
+        amalgamated_content += f"\n/* Shared definitions from src/common/{common_name} */\n{common_body}\n"
+
     # Add internal header content
     internal_header = read_file(source_path / "HiAE_internal.h")
     if not internal_header:
@@ -320,6 +337,7 @@ def create_amalgamation():
         internal_body = internal_content.group(1)
         # Remove includes we've already handled
         internal_body = re.sub(r'#include\s+"HiAE\.h"', '', internal_body)
+        internal_body = re.sub(r'#include\s+"\.\./common/[^"]+"', '', internal_body)
         internal_body = re.sub(r'#include\s+<[^>]+>', '', internal_body)
         amalgamated_content += f"\n/* Internal definitions from HiAE_internal.h */\n{internal_body}\n"
     
diff --git a/src/common/common.h b/src/common/common.h
new file mode 100644
index 0000000..b6cf210
--- /dev/null
+++ b/src/common/common.h
@@ -0,0 +1,82 @@
+#ifndef hiae_common_H
+#define hiae_common_H
+
+/*
+ * Compiler / target capability detection shared by every translation unit.
+ *
+ * This header must be included by all implementation files and by the
+ * dispatchers, so that all of them agree on which implementations exist.
+ * Keeping this block in a single place is what prevents two translation
+ * units from disagreeing about the availability of an implementation.
+ */
+
+#ifdef __linux__
+#    define HAVE_SYS_AUXV_H
+#    define HAVE_GETAUXVAL
+#endif
+#ifdef __ANDROID_API__
+#    if __ANDROID_API__ < 18
+#        undef HAVE_GETAUXVAL
+#    endif
+#    define HAVE_ANDROID_GETCPUFEATURES
+#endif
+#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
+#    define HAVE_CPUID
+#    define NATIVE_LITTLE_ENDIAN
+#    if defined(__clang__) || defined(__GNUC__)
+#        define HAVE_AVX_ASM
+#    endif
+#    define HAVE_AVXINTRIN_H
+#    define HAVE_AVX2INTRIN_H
+#    define HAVE_AVX512FINTRIN_H
+#    define HAVE_TMMINTRIN_H
+#    define HAVE_WMMINTRIN_H
+#    define HAVE_VAESINTRIN_H
+#    ifdef __GNUC__
+#        if !__has_include(<vaesintrin.h>)
+#            undef HAVE_VAESINTRIN_H
+#        endif
+#    endif
+/* target pragmas don't define these flags on clang-cl (an alternative clang driver for Windows) */
+#    if defined(__clang__) && defined(_MSC_BUILD) && defined(_MSC_VER) && \
+        (defined(_M_IX86) || defined(_M_AMD64)) && !defined(__SSE3__)
+#        undef __SSE3__
+#        undef __SSSE3__
+#        undef __SSE4_1__
+#        undef __AVX__
+#        undef __AVX2__
+#        undef __AVX512F__
+#        undef __AES__
+#        undef __VAES__
+
+#        define __SSE3__    1
+#        define __SSSE3__   1
+#        define __SSE4_1__  1
+#        define __AVX__     1
+#        define __AVX2__    1
+#        define __AVX512F__ 1
+#        define __AES__     1
+#        define __VAES__    1
+
+/*
+ * The macros above were synthesized so that the intrinsics headers expose
+ * everything the target pragmas can emit. They describe the compiler, not
+ * the CPU the code will run on, and must therefore never be used to decide
+ * which implementations get compiled in. See cpu.h.
+ */
+#        define HIAE_ISA_MACROS_SYNTHESIZED 1
+#    endif
+
+#endif
+
+#ifdef DISABLE_AVX2
+#    undef HAVE_AVXINTRIN_H
+#    undef HAVE_AVX2INTRIN_H
+#    undef HAVE_AVX512FINTRIN_H
+#    undef HAVE_VAESINTRIN_H
+#endif
+#ifdef DISABLE_AVX512
+#    undef HAVE_AVX512FINTRIN_H
+#endif
+
+#endif /* hiae_common_H */
diff --git a/src/common/cpu.h b/src/common/cpu.h
new file mode 100644
index 0000000..3b3b826
--- /dev/null
+++ b/src/common/cpu.h
@@ -0,0 +1,32 @@
+#ifndef hiae_cpu_H
+#define hiae_cpu_H
+
+#include "common.h"
+
+/*
+ * HIAE*_HAS_HW_AES is set when the compilation baseline itself guarantees that
+ * a hardware implementation of the corresponding variant is present. In that
+ * case the software implementation is not compiled in at all.
+ *
+ * Every translation unit that needs to know whether the software
+ * implementation exists must test these macros, and only these macros.
+ * Testing __AES__ & friends directly is not equivalent: on clang-cl they are
+ * synthesized in common.h so that the intrinsics headers work, and they then
+ * describe the compiler rather than the target CPU.
+ */
+
+#if defined(__ARM_FEATURE_CRYPTO)
+#    define HIAE_HAS_HW_AES
+#    define HIAEX2_HAS_HW_AES
+#    define HIAEX4_HAS_HW_AES
+#elif !defined(HIAE_ISA_MACROS_SYNTHESIZED)
+#    if defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)
+#        define HIAE_HAS_HW_AES
+#        define HIAEX4_HAS_HW_AES
+#    endif
+#    if defined(__AES__) && defined(__VAES__) && defined(__AVX2__)
+#        define HIAEX2_HAS_HW_AES
+#    endif
+#endif
+
+#endif /* hiae_cpu_H */
diff --git a/src/hiae/HiAE.c b/src/hiae/HiAE.c
index 34e21bb..76d1263 100644
--- a/src/hiae/HiAE.c
+++ b/src/hiae/HiAE.c
@@ -11,67 +11,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#ifdef __linux__
-#    define HAVE_SYS_AUXV_H
-#    define HAVE_GETAUXVAL
-#endif
-#ifdef __ANDROID_API__
-#    if __ANDROID_API__ < 18
-#        undef HAVE_GETAUXVAL
-#    endif
-#    define HAVE_ANDROID_GETCPUFEATURES
-#endif
-#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
-#    define HAVE_CPUID
-#    define NATIVE_LITTLE_ENDIAN
-#    if defined(__clang__) || defined(__GNUC__)
-#        define HAVE_AVX_ASM
-#    endif
-#    define HAVE_AVXINTRIN_H
-#    define HAVE_AVX2INTRIN_H
-#    define HAVE_AVX512FINTRIN_H
-#    define HAVE_TMMINTRIN_H
-#    define HAVE_WMMINTRIN_H
-#    define HAVE_VAESINTRIN_H
-#    ifdef __GNUC__
-#        if !__has_include(<vaesintrin.h>)
-#            undef HAVE_VAESINTRIN_H
-#        endif
-#    endif
-/* target pragmas don't define these flags on clang-cl (an alternative clang driver for Windows) */
-#    if defined(__clang__) && defined(_MSC_BUILD) && defined(_MSC_VER) && \
-        (defined(_M_IX86) || defined(_M_AMD64)) && !defined(__SSE3__)
-#        undef __SSE3__
-#        undef __SSSE3__
-#        undef __SSE4_1__
-#        undef __AVX__
-#        undef __AVX2__
-#        undef __AVX512F__
-#        undef __AES__
-#        undef __VAES__
-
-#        define __SSE3__    1
-#        define __SSSE3__   1
-#        define __SSE4_1__  1
-#        define __AVX__     1
-#        define __AVX2__    1
-#        define __AVX512F__ 1
-#        define __AES__     1
-#        define __VAES__    1
-#    endif
-
-#endif
-
-#ifdef DISABLE_AVX2
-#    undef HAVE_AVXINTRIN_H
-#    undef HAVE_AVX2INTRIN_H
-#    undef HAVE_AVX512FINTRIN_H
-#    undef HAVE_VAESINTRIN_H
-#endif
-#ifdef DISABLE_AVX512
-#    undef HAVE_AVX512FINTRIN_H
-#endif
-
 #ifdef HAVE_ANDROID_GETCPUFEATURES
 #    include <cpu-features.h>
 #endif
@@ -374,8 +313,7 @@ hiae_runtime_get_cpu_features(void)
 }
 
 // External declarations for implementation tables
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAE_HAS_HW_AES
 extern const HiAE_impl_t hiae_software_impl;
 #endif
 #if defined(__x86_64__) || defined(_M_X64)
@@ -395,8 +333,7 @@ hiae_get_impl_by_name(const char *name)
         return NULL;
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAE_HAS_HW_AES
     if (strcmp(name, "Software") == 0) {
         return (HiAE_impl_t *) &hiae_software_impl;
     }
@@ -450,10 +387,14 @@ hiae_init_dispatch(void)
         hiae_runtime_get_cpu_features();
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
-    // Default to software implementation when hardware AES+VAES+AVX512 is not available
+    // Start from the implementation the compilation baseline guarantees, then
+    // upgrade it below if the CPU actually supports something faster.
+#ifndef HIAE_HAS_HW_AES
     hiae_impl = (HiAE_impl_t *) &hiae_software_impl;
+#elif defined(__x86_64__) || defined(_M_X64)
+    hiae_impl = (HiAE_impl_t *) &hiae_aesni_impl;
+#elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
+    hiae_impl = (HiAE_impl_t *) &hiae_arm_impl;
 #endif
 
     // Select best available implementation based on CPU features
@@ -471,23 +412,6 @@ hiae_init_dispatch(void)
     }
 #endif
 
-#if (defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || defined(__ARM_FEATURE_CRYPTO)
-    // When hardware AES+VAES+AVX512 is available, ensure we have a valid implementation
-    if (hiae_impl == NULL) {
-#    if defined(__x86_64__) || defined(_M_X64)
-        // Fallback to AES-NI on x86-64 if available
-        if (hiae_aesni_impl.init != NULL) {
-            hiae_impl = (HiAE_impl_t *) &hiae_aesni_impl;
-        }
-#    elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
-        // Fallback to ARM NEON on ARM64 if available
-        if (hiae_arm_impl.init != NULL) {
-            hiae_impl = (HiAE_impl_t *) &hiae_arm_impl;
-        }
-#    endif
-    }
-#endif
-
 #ifdef SOFTAES_ENABLED
     (void) softaes_block_zero;
     (void) softaes_block_load;
diff --git a/src/hiae/HiAE_internal.h b/src/hiae/HiAE_internal.h
index e266a62..5e13028 100644
--- a/src/hiae/HiAE_internal.h
+++ b/src/hiae/HiAE_internal.h
@@ -1,6 +1,8 @@
 #ifndef HIAE_INTERNAL_H
 #define HIAE_INTERNAL_H
 
+#include "../common/common.h"
+#include "../common/cpu.h"
 #include "HiAE.h"
 #include <string.h>
 
diff --git a/src/hiae/HiAE_software.c b/src/hiae/HiAE_software.c
index e0d37bd..ae35c07 100644
--- a/src/hiae/HiAE_software.c
+++ b/src/hiae/HiAE_software.c
@@ -2,8 +2,7 @@
 #include "HiAE_internal.h"
 
 // Only compile software implementation if hardware AES+VAES+AVX512 is not available
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAE_HAS_HW_AES
 
 #    define FAVOR_PERFORMANCE
 #    include "softaes.h"
@@ -720,4 +719,4 @@ const HiAE_impl_t hiae_software_impl = { .name                 = "Software",
                                          .decrypt              = HiAE_decrypt_software,
                                          .mac                  = HiAE_mac_software };
 
-#endif // !defined(__AES__) && !defined(__ARM_FEATURE_CRYPTO)
+#endif /* !HIAE_HAS_HW_AES */
diff --git a/src/hiae/HiAE_vaes_avx512.c b/src/hiae/HiAE_vaes_avx512.c
index df32914..3fc2589 100644
--- a/src/hiae/HiAE_vaes_avx512.c
+++ b/src/hiae/HiAE_vaes_avx512.c
@@ -1,8 +1,9 @@
 #include "HiAE.h"
 #include "HiAE_internal.h"
 
+/* clang-cl can build this implementation; MSVC proper cannot (no target pragmas) */
 #if (defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)) && \
-    !defined(_MSC_VER)
+    (!defined(_MSC_VER) || defined(__clang__))
 
 #    ifdef __clang__
 #        if __clang_major__ >= 18
diff --git a/src/hiaex2/HiAEx2.c b/src/hiaex2/HiAEx2.c
index 6aa2cfd..d328d08 100644
--- a/src/hiaex2/HiAEx2.c
+++ b/src/hiaex2/HiAEx2.c
@@ -11,67 +11,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#ifdef __linux__
-#    define HAVE_SYS_AUXV_H
-#    define HAVE_GETAUXVAL
-#endif
-#ifdef __ANDROID_API__
-#    if __ANDROID_API__ < 18
-#        undef HAVE_GETAUXVAL
-#    endif
-#    define HAVE_ANDROID_GETCPUFEATURES
-#endif
-#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
-#    define HAVE_CPUID
-#    define NATIVE_LITTLE_ENDIAN
-#    if defined(__clang__) || defined(__GNUC__)
-#        define HAVE_AVX_ASM
-#    endif
-#    define HAVE_AVXINTRIN_H
-#    define HAVE_AVX2INTRIN_H
-#    define HAVE_AVX512FINTRIN_H
-#    define HAVE_TMMINTRIN_H
-#    define HAVE_WMMINTRIN_H
-#    define HAVE_VAESINTRIN_H
-#    ifdef __GNUC__
-#        if !__has_include(<vaesintrin.h>)
-#            undef HAVE_VAESINTRIN_H
-#        endif
-#    endif
-/* target pragmas don't define these flags on clang-cl (an alternative clang driver for Windows) */
-#    if defined(__clang__) && defined(_MSC_BUILD) && defined(_MSC_VER) && \
-        (defined(_M_IX86) || defined(_M_AMD64)) && !defined(__SSE3__)
-#        undef __SSE3__
-#        undef __SSSE3__
-#        undef __SSE4_1__
-#        undef __AVX__
-#        undef __AVX2__
-#        undef __AVX512F__
-#        undef __AES__
-#        undef __VAES__
-
-#        define __SSE3__    1
-#        define __SSSE3__   1
-#        define __SSE4_1__  1
-#        define __AVX__     1
-#        define __AVX2__    1
-#        define __AVX512F__ 1
-#        define __AES__     1
-#        define __VAES__    1
-#    endif
-
-#endif
-
-#ifdef DISABLE_AVX2
-#    undef HAVE_AVXINTRIN_H
-#    undef HAVE_AVX2INTRIN_H
-#    undef HAVE_AVX512FINTRIN_H
-#    undef HAVE_VAESINTRIN_H
-#endif
-#ifdef DISABLE_AVX512
-#    undef HAVE_AVX512FINTRIN_H
-#endif
-
 #ifdef HAVE_ANDROID_GETCPUFEATURES
 #    include <cpu-features.h>
 #endif
@@ -374,7 +313,7 @@ hiaex2_runtime_get_cpu_features(void)
 }
 
 // External declarations for implementation tables
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX2__)) || defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX2_HAS_HW_AES
 extern const HiAEx2_impl_t hiaex2_software_impl;
 #endif
 #if defined(__x86_64__) || defined(_M_X64)
@@ -394,7 +333,7 @@ hiaex2_get_impl_by_name(const char *name)
         return NULL;
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX2__)) || defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX2_HAS_HW_AES
     if (strcmp(name, "Software") == 0) {
         return (HiAEx2_impl_t *) &hiaex2_software_impl;
     }
@@ -448,9 +387,14 @@ hiaex2_init_dispatch(void)
         hiaex2_runtime_get_cpu_features();
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX2__)) || defined(__ARM_FEATURE_CRYPTO))
-    // Default to software implementation when hardware AES+VAES+AVX2 is not available
+    // Start from the implementation the compilation baseline guarantees, then
+    // upgrade it below if the CPU actually supports something faster.
+#ifndef HIAEX2_HAS_HW_AES
     hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_software_impl;
+#elif defined(__x86_64__) || defined(_M_X64)
+    hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_vaes_avx2_impl;
+#elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
+    hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_arm_impl;
 #endif
 
     // Select best available implementation based on CPU features
@@ -468,31 +412,6 @@ hiaex2_init_dispatch(void)
         hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_arm_impl;
     }
 #endif
-
-#if (defined(__AES__) && defined(__VAES__) && defined(__AVX2__)) || defined(__ARM_FEATURE_CRYPTO)
-    // When hardware AES+VAES+AVX2 is available, ensure we have a valid implementation
-    if (hiaex2_impl == NULL) {
-#    if defined(__x86_64__) || defined(_M_X64)
-        // Fallback to VAES-AVX2 on x86-64 if available
-        if (hiaex2_vaes_avx2_impl.init != NULL) {
-            hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_vaes_avx2_impl;
-        }
-#    elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
-        // Fallback to ARM NEON on ARM64 if available
-        if (hiaex2_arm_impl.init != NULL) {
-            hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_arm_impl;
-        }
-#    endif
-    }
-#elif defined(__AES__) && defined(__AVX__) && (defined(__x86_64__) || defined(_M_X64))
-    // When hardware AES+AVX is available, ensure we have a valid implementation
-    if (hiaex2_impl == NULL) {
-        // Fallback to AESNI-AVX on x86-64 if available
-        if (hiaex2_aesni_avx_impl.init != NULL) {
-            hiaex2_impl = (HiAEx2_impl_t *) &hiaex2_aesni_avx_impl;
-        }
-    }
-#endif
 }
 
 // Public API function to initialize library
diff --git a/src/hiaex2/HiAEx2_internal.h b/src/hiaex2/HiAEx2_internal.h
index 58769b6..b06f13c 100644
--- a/src/hiaex2/HiAEx2_internal.h
+++ b/src/hiaex2/HiAEx2_internal.h
@@ -1,6 +1,8 @@
 #ifndef HiAEx2_INTERNAL_H
 #define HiAEx2_INTERNAL_H
 
+#include "../common/common.h"
+#include "../common/cpu.h"
 #include "HiAEx2.h"
 #include <string.h>
 
diff --git a/src/hiaex2/HiAEx2_software.c b/src/hiaex2/HiAEx2_software.c
index 9b67e77..a0bcef6 100644
--- a/src/hiaex2/HiAEx2_software.c
+++ b/src/hiaex2/HiAEx2_software.c
@@ -2,7 +2,7 @@
 #include "HiAEx2_internal.h"
 
 // Only compile software implementation if hardware AES+VAES+AVX2 is not available
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX2__)) || defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX2_HAS_HW_AES
 
 #    define FAVOR_PERFORMANCE
 #    include "softaes.h"
@@ -681,4 +681,4 @@ const HiAEx2_impl_t hiaex2_software_impl = { .name         = "Software",
                                              .decrypt = HiAEx2_decrypt_software,
                                              .mac     = HiAEx2_mac_software };
 
-#endif // !defined(__AES__) && !defined(__ARM_FEATURE_CRYPTO)
+#endif /* !HIAEX2_HAS_HW_AES */
diff --git a/src/hiaex4/HiAEx4.c b/src/hiaex4/HiAEx4.c
index 183f9b8..1b9b23f 100644
--- a/src/hiaex4/HiAEx4.c
+++ b/src/hiaex4/HiAEx4.c
@@ -11,67 +11,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#ifdef __linux__
-#    define HAVE_SYS_AUXV_H
-#    define HAVE_GETAUXVAL
-#endif
-#ifdef __ANDROID_API__
-#    if __ANDROID_API__ < 18
-#        undef HAVE_GETAUXVAL
-#    endif
-#    define HAVE_ANDROID_GETCPUFEATURES
-#endif
-#if defined(__i386__) || defined(_M_IX86) || defined(__x86_64__) || defined(_M_AMD64)
-#    define HAVE_CPUID
-#    define NATIVE_LITTLE_ENDIAN
-#    if defined(__clang__) || defined(__GNUC__)
-#        define HAVE_AVX_ASM
-#    endif
-#    define HAVE_AVXINTRIN_H
-#    define HAVE_AVX2INTRIN_H
-#    define HAVE_AVX512FINTRIN_H
-#    define HAVE_TMMINTRIN_H
-#    define HAVE_WMMINTRIN_H
-#    define HAVE_VAESINTRIN_H
-#    ifdef __GNUC__
-#        if !__has_include(<vaesintrin.h>)
-#            undef HAVE_VAESINTRIN_H
-#        endif
-#    endif
-/* target pragmas don't define these flags on clang-cl (an alternative clang driver for Windows) */
-#    if defined(__clang__) && defined(_MSC_BUILD) && defined(_MSC_VER) && \
-        (defined(_M_IX86) || defined(_M_AMD64)) && !defined(__SSE3__)
-#        undef __SSE3__
-#        undef __SSSE3__
-#        undef __SSE4_1__
-#        undef __AVX__
-#        undef __AVX2__
-#        undef __AVX512F__
-#        undef __AES__
-#        undef __VAES__
-
-#        define __SSE3__    1
-#        define __SSSE3__   1
-#        define __SSE4_1__  1
-#        define __AVX__     1
-#        define __AVX2__    1
-#        define __AVX512F__ 1
-#        define __AES__     1
-#        define __VAES__    1
-#    endif
-
-#endif
-
-#ifdef DISABLE_AVX2
-#    undef HAVE_AVXINTRIN_H
-#    undef HAVE_AVX2INTRIN_H
-#    undef HAVE_AVX512FINTRIN_H
-#    undef HAVE_VAESINTRIN_H
-#endif
-#ifdef DISABLE_AVX512
-#    undef HAVE_AVX512FINTRIN_H
-#endif
-
 #ifdef HAVE_ANDROID_GETCPUFEATURES
 #    include <cpu-features.h>
 #endif
@@ -374,8 +313,7 @@ hiaex4_runtime_get_cpu_features(void)
 }
 
 // External declarations for implementation tables
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX4_HAS_HW_AES
 extern const HiAEx4_impl_t hiaex4_software_impl;
 #endif
 #if defined(__x86_64__) || defined(_M_X64)
@@ -394,8 +332,7 @@ hiaex4_get_impl_by_name(const char *name)
         return NULL;
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX4_HAS_HW_AES
     if (strcmp(name, "Software") == 0) {
         return (HiAEx4_impl_t *) &hiaex4_software_impl;
     }
@@ -446,10 +383,14 @@ hiaex4_init_dispatch(void)
         hiaex4_runtime_get_cpu_features();
     }
 
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
-    // Default to software implementation when hardware AES+VAES+AVX512 is not available
+    // Start from the implementation the compilation baseline guarantees, then
+    // upgrade it below if the CPU actually supports something faster.
+#ifndef HIAEX4_HAS_HW_AES
     hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_software_impl;
+#elif defined(__x86_64__) || defined(_M_X64)
+    hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_vaes_avx512_impl;
+#elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
+    hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_arm_impl;
 #endif
 
     // Select best available implementation based on CPU features
@@ -465,23 +406,6 @@ hiaex4_init_dispatch(void)
         hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_arm_impl;
     }
 #endif
-
-#if (defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || defined(__ARM_FEATURE_CRYPTO)
-    // When hardware AES+VAES+AVX512 is available, ensure we have a valid implementation
-    if (hiaex4_impl == NULL) {
-#    if defined(__x86_64__) || defined(_M_X64)
-        // Fallback to VAES-AVX512 on x86-64 if available
-        if (hiaex4_vaes_avx512_impl.init != NULL) {
-            hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_vaes_avx512_impl;
-        }
-#    elif defined(__aarch64__) || defined(_M_ARM64) || defined(__arm64__)
-        // Fallback to ARM NEON on ARM64 if available
-        if (hiaex4_arm_impl.init != NULL) {
-            hiaex4_impl = (HiAEx4_impl_t *) &hiaex4_arm_impl;
-        }
-#    endif
-    }
-#endif
 }
 
 // Public API function to initialize library
diff --git a/src/hiaex4/HiAEx4_internal.h b/src/hiaex4/HiAEx4_internal.h
index be4f3e5..171438e 100644
--- a/src/hiaex4/HiAEx4_internal.h
+++ b/src/hiaex4/HiAEx4_internal.h
@@ -1,6 +1,8 @@
 #ifndef HiAEx4_INTERNAL_H
 #define HiAEx4_INTERNAL_H
 
+#include "../common/common.h"
+#include "../common/cpu.h"
 #include "HiAEx4.h"
 #include <string.h>
 
diff --git a/src/hiaex4/HiAEx4_software.c b/src/hiaex4/HiAEx4_software.c
index 8b22b30..6179bd6 100644
--- a/src/hiaex4/HiAEx4_software.c
+++ b/src/hiaex4/HiAEx4_software.c
@@ -2,8 +2,7 @@
 #include "HiAEx4_internal.h"
 
 // Only compile software implementation if hardware AES+VAES+AVX512 is not available
-#if !((defined(__AES__) && defined(__VAES__) && defined(__AVX512F__)) || \
-      defined(__ARM_FEATURE_CRYPTO))
+#ifndef HIAEX4_HAS_HW_AES
 
 #    define FAVOR_PERFORMANCE
 #    include "softaes.h"
@@ -706,4 +705,4 @@ const HiAEx4_impl_t hiaex4_software_impl = { .name         = "Software",
                                              .decrypt = HiAEx4_decrypt_software,
                                              .mac     = HiAEx4_mac_software };
 
-#endif // !defined(__AES__) && !defined(__ARM_FEATURE_CRYPTO)
+#endif /* !HIAEX4_HAS_HW_AES */