diff --git a/library/alignment.h b/library/alignment.h
index 211e7ac37..ff811e34d 100644
--- a/library/alignment.h
+++ b/library/alignment.h
@@ -35,7 +35,7 @@
  * efficient when this is not defined.
  */
 #if defined(__ARM_FEATURE_UNALIGNED) \
-    || defined(__i386__) || defined(__amd64__) || defined(__x86_64__) \
+    || defined(MBEDTLS_ARCH_IS_X86) || defined(MBEDTLS_ARCH_IS_X64) \
     || defined(_M_ARM64) || defined(_M_ARM64EC)
 /*
  * __ARM_FEATURE_UNALIGNED is defined where appropriate by armcc, gcc 7, clang 9
diff --git a/library/common.h b/library/common.h
index fd2aecb20..6c65084f4 100644
--- a/library/common.h
+++ b/library/common.h
@@ -194,8 +194,7 @@ inline void mbedtls_xor(unsigned char *r, const unsigned char *a, const unsigned
         uint8x16_t x = veorq_u8(v1, v2);
         vst1q_u8(r + i, x);
     }
-#elif defined(__amd64__) || defined(__x86_64__) || \
-    defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
+#elif defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64)
     /* This codepath probably only makes sense on architectures with 64-bit registers */
     for (; (i + 8) <= n; i += 8) {
         uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
@@ -234,8 +233,7 @@ static inline void mbedtls_xor_no_simd(unsigned char *r,
 {
     size_t i = 0;
 #if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
-#if defined(__amd64__) || defined(__x86_64__) || \
-    defined(__aarch64__) || defined(_M_ARM64) || defined(_M_ARM64EC)
+#if defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64)
     /* This codepath probably only makes sense on architectures with 64-bit registers */
     for (; (i + 8) <= n; i += 8) {
         uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);