diff --git a/lib/lz4.c b/lib/lz4.c
index 955e864..104227c 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -379,14 +379,16 @@
 
 /* __pack instructions are safer, but compiler specific, hence potentially problematic for some compilers */
 /* currently only defined for gcc and icc */
-typedef union { U16 u16; U32 u32; reg_t uArch; } __attribute__((packed)) LZ4_unalign;
+typedef struct { U16 u16; } __attribute__((packed)) LZ4_unalign16;
+typedef struct { U32 u32; } __attribute__((packed)) LZ4_unalign32;
+typedef struct { reg_t uArch; } __attribute__((packed)) LZ4_unalignST;
 
-static U16 LZ4_read16(const void* ptr) { return ((const LZ4_unalign*)ptr)->u16; }
-static U32 LZ4_read32(const void* ptr) { return ((const LZ4_unalign*)ptr)->u32; }
-static reg_t LZ4_read_ARCH(const void* ptr) { return ((const LZ4_unalign*)ptr)->uArch; }
+static U16 LZ4_read16(const void* ptr) { return ((const LZ4_unalign16*)ptr)->u16; }
+static U32 LZ4_read32(const void* ptr) { return ((const LZ4_unalign32*)ptr)->u32; }
+static reg_t LZ4_read_ARCH(const void* ptr) { return ((const LZ4_unalignST*)ptr)->uArch; }
 
-static void LZ4_write16(void* memPtr, U16 value) { ((LZ4_unalign*)memPtr)->u16 = value; }
-static void LZ4_write32(void* memPtr, U32 value) { ((LZ4_unalign*)memPtr)->u32 = value; }
+static void LZ4_write16(void* memPtr, U16 value) { ((LZ4_unalign16*)memPtr)->u16 = value; }
+static void LZ4_write32(void* memPtr, U32 value) { ((LZ4_unalign32*)memPtr)->u32 = value; }
 
 #else  /* safe and portable access using memcpy() */