diff --git a/src/cmock.c b/src/cmock.c
index 1cc1725..190284a 100644
--- a/src/cmock.c
+++ b/src/cmock.c
@@ -25,8 +25,12 @@ const char* CMockStringMismatch    = "Function called with unexpected argument v
     static unsigned char*         CMock_Guts_Buffer = NULL;
     static CMOCK_MEM_INDEX_TYPE   CMock_Guts_BufferSize = CMOCK_MEM_ALIGN_SIZE;
     static CMOCK_MEM_INDEX_TYPE   CMock_Guts_FreePtr = CMOCK_MEM_ALIGN_SIZE;
+#else
+#if !defined(UNITY_EXCLUDE_STDDEF_H) && defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
+    static _Alignas(max_align_t) long long CMock_Guts_Space[(CMOCK_MEM_SIZE + CMOCK_MEM_ALIGN_SIZE + sizeof(long long) - 1) / sizeof(long long)];
 #else
     static long long              CMock_Guts_Space[(CMOCK_MEM_SIZE + CMOCK_MEM_ALIGN_SIZE + sizeof(long long) - 1) / sizeof(long long)];
+#endif
     static unsigned char*         CMock_Guts_Buffer = (unsigned char*)CMock_Guts_Space;
     static CMOCK_MEM_INDEX_TYPE   CMock_Guts_BufferSize = CMOCK_MEM_SIZE + CMOCK_MEM_ALIGN_SIZE;//sizeof(CMock_Guts_Space);
     static CMOCK_MEM_INDEX_TYPE   CMock_Guts_FreePtr = CMOCK_MEM_ALIGN_SIZE;
diff --git a/src/cmock_internals.h b/src/cmock_internals.h
index b3d23f5..118e28c 100644
--- a/src/cmock_internals.h
+++ b/src/cmock_internals.h
@@ -76,6 +76,18 @@ extern const char* CMockStringMismatch;
     #else
         #define CMOCK_MEM_ALIGN (2)
     #endif
+
+    /* Boost to 8-byte alignment when 64-bit integers or doubles are enabled,
+     * since those types require 8-byte alignment even on 32-bit platforms */
+    #if CMOCK_MEM_ALIGN < 3
+        #if defined(UNITY_SUPPORT_64) || defined(UNITY_INCLUDE_DOUBLE)
+            #undef  CMOCK_MEM_ALIGN
+            #define CMOCK_MEM_ALIGN (3)
+        #endif
+    #endif
+
+    /* sentinel: CMOCK_MEM_ALIGN was auto-detected (not user-supplied) */
+    #define CMOCK_MEM_ALIGN_AUTO
 #endif
 
 /* amount of memory to allow cmock to use in its internal heap */
@@ -98,6 +110,17 @@ extern const char* CMockStringMismatch;
 /* automatically calculated defs for easier reading */
 #define CMOCK_MEM_ALIGN_SIZE  (CMOCK_MEM_INDEX_TYPE)(1u << CMOCK_MEM_ALIGN)
 #define CMOCK_MEM_ALIGN_MASK  (CMOCK_MEM_INDEX_TYPE)(CMOCK_MEM_ALIGN_SIZE - 1)
+
+/* When CMOCK_MEM_ALIGN was auto-detected and stddef.h is available (C11+),
+ * use sizeof(max_align_t) to guarantee alignment is sufficient for all
+ * fundamental types on this platform, taking the larger of the two values */
+#if defined(CMOCK_MEM_ALIGN_AUTO) && !defined(UNITY_EXCLUDE_STDDEF_H) && defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L)
+    #undef  CMOCK_MEM_ALIGN_SIZE
+    #undef  CMOCK_MEM_ALIGN_MASK
+    #define CMOCK_MEM_ALIGN_SIZE  (CMOCK_MEM_INDEX_TYPE)(sizeof(max_align_t) > (1u << CMOCK_MEM_ALIGN) ? sizeof(max_align_t) : (1u << CMOCK_MEM_ALIGN))
+    #define CMOCK_MEM_ALIGN_MASK  (CMOCK_MEM_INDEX_TYPE)(CMOCK_MEM_ALIGN_SIZE - 1)
+#endif
+
 #define CMOCK_MEM_INDEX_SIZE  (CMOCK_MEM_INDEX_TYPE)(CMOCK_MEM_PTR_AS_INT)((sizeof(CMOCK_MEM_INDEX_TYPE) > CMOCK_MEM_ALIGN_SIZE) ? sizeof(CMOCK_MEM_INDEX_TYPE) : CMOCK_MEM_ALIGN_SIZE)