diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # Revision history for Z-Data
 
+## 0.8.4.0  -- 2021-06-03
+
+* `arrVec` from `Z.Data.Vector` now could convert between vector(array slice) and array back and forth.
+* Fix a CPP bug in `no-avx` build flag.
+
 ## 0.8.3.0  -- 2021-06-02
 
 * Fix numeric literals' `Print` instances when precedence > 6 and  value < 0.
diff --git a/Z-Data.cabal b/Z-Data.cabal
--- a/Z-Data.cabal
+++ b/Z-Data.cabal
@@ -1,6 +1,6 @@
 cabal-version:      2.4
 name:               Z-Data
-version:            0.8.3.0
+version:            0.8.4.0
 synopsis:           Array, vector and text
 description:        This package provides array, slice and text operations
 license:            BSD-3-Clause
@@ -242,6 +242,7 @@
     third_party/Turbo-Base64/turbob64c.c
     third_party/Turbo-Base64/turbob64d.c
     third_party/Turbo-Base64/turbob64sse.c
+    -- third_party/Turbo-Base64/turbob64avx2.c, this file is conditionally included from bytes.c
     third_party/utf8rewind/source/internal/casemapping.c
     third_party/utf8rewind/source/internal/codepoint.c
     third_party/utf8rewind/source/internal/composition.c
diff --git a/Z/Data/Vector/Base.hs b/Z/Data/Vector/Base.hs
--- a/Z/Data/Vector/Base.hs
+++ b/Z/Data/Vector/Base.hs
@@ -135,10 +135,10 @@
     -- | Create a vector by slicing an array(with offset and length).
     fromArr :: IArray v a -> Int -> Int -> v a
 
--- | Construct a 'Vec' by slicing a whole array.
-arrVec :: Vec v a => IArray v a -> v a
+-- | Change vector types based on same array type, e.g. construct an array from a slice, or vice-versa.
+arrVec :: (Vec v a, Vec u a, IArray v ~ IArray u) => v a -> u a
 {-# INLINE arrVec #-}
-arrVec arr = fromArr arr 0 (sizeofArr arr)
+arrVec bs = let (arr, s, l) = toArr bs in fromArr arr s l
 
 instance Vec Array a where
     type IArray Array = Array
diff --git a/cbits/bytes.c b/cbits/bytes.c
--- a/cbits/bytes.c
+++ b/cbits/bytes.c
@@ -259,7 +259,7 @@
     tb64avx2enc(input+off, (size_t)len, output+output_off);
 #elif defined(__AVX__) && !defined(NO_AVX)
     tb64avxenc(input+off, (size_t)len, output+output_off);
-#elif defined(__SSE3__)
+#elif defined(__SSSE3__)
     tb64sseenc(input+off, (size_t)len, output+output_off);
 #else
     tb64xenc(input+off, (size_t)len, output+output_off);
@@ -271,7 +271,7 @@
     return (HsInt)tb64avx2dec(input+off, (size_t)len, output);
 #elif defined(__AVX__) && !defined(NO_AVX)
     return (HsInt)tb64avxdec(input+off, (size_t)len, output);
-#elif defined(__SSE3__)
+#elif defined(__SSSE3__)
     return (HsInt)tb64ssedec(input+off, (size_t)len, output);
 #else
     return (HsInt)tb64xdec(input+off, (size_t)len, output);
diff --git a/third_party/Turbo-Base64/turbob64sse.c b/third_party/Turbo-Base64/turbob64sse.c
--- a/third_party/Turbo-Base64/turbob64sse.c
+++ b/third_party/Turbo-Base64/turbob64sse.c
@@ -34,12 +34,14 @@
 
 #include <string.h>
 
-  #if defined(__AVX__)
+  #if defined(__AVX__) && !defined(NO_AVX)
 #include <immintrin.h>
-#define FUNPREF tb64avx
+#define FUNPREF_ENC tb64avxenc
+#define FUNPREF_DEC tb64avxdec
   #elif defined(__SSE4_1__)
 #include <smmintrin.h>
-#define FUNPREF tb64sse
+#define FUNPREF_ENC tb64sseenc
+#define FUNPREF_DEC tb64ssedec
   #elif defined(__SSSE3__)
     #ifdef __powerpc64__
 #define __SSE__   1
@@ -47,7 +49,8 @@
 #define __SSE3__  1
 #define NO_WARN_X86_INTRINSICS 1
     #endif
-#define FUNPREF tb64sse
+#define FUNPREF_ENC tb64sseenc
+#define FUNPREF_DEC tb64ssedec
 #include <tmmintrin.h>
   #elif defined(__SSE2__)
 #include <emmintrin.h>
@@ -195,11 +198,11 @@
 #elif defined(__SSSE3__) //----------------- SSSE3 / SSE4.1 / AVX (derived from the AVX2 functions ) -----------------------------------------------------------------
 
 #define OVD 4
-size_t TEMPLATE2(FUNPREF, dec)(const unsigned char *in, size_t inlen, unsigned char *out) {
+size_t FUNPREF_DEC(const unsigned char *in, size_t inlen, unsigned char *out) {
   if(inlen >= 16+OVD) {
     const unsigned char *ip;
           unsigned char *op; 
-      #ifdef __AVX__
+      #if defined(__AVX__) && !defined(NO_AVX)
     #define ND 64
       #else
     #define ND 32
@@ -241,7 +244,7 @@
       CHECK1(MM_B64CHK(iv3, shifted3, check_asso, check_values, vx));
         #endif
     }
-      #ifdef __AVX__
+      #if defined(__AVX__) && !defined(NO_AVX)
     for(; ip < (in+inlen)-(16+OVD); ip += 16, op += (16/4)*3) {
       #else
     if(ip < (in+inlen)-(16+OVD)) {
@@ -250,7 +253,7 @@
       __m128i ov0, shifted0; MM_MAP8TO6(iv0, shifted0,delta_asso, delta_values, ov0); MM_PACK8TO6(ov0, cpv);
       _mm_storeu_si128((__m128i*) op, ov0);                                                  
       CHECK1(MM_B64CHK(iv0, shifted0, check_asso, check_values, vx));
-        #ifndef __AVX__
+        #if defined(__AVX__) && !defined(NO_AVX)
       ip += 16; op += (16/4)*3;
         #endif
     }
@@ -262,11 +265,11 @@
 }
 
 #define OVE 8
-size_t TEMPLATE2(FUNPREF, enc)(const unsigned char* in, size_t inlen, unsigned char *out) { 
+size_t FUNPREF_ENC(const unsigned char* in, size_t inlen, unsigned char *out) { 
   const unsigned char *ip = in; 
         unsigned char *op = out;
   size_t   outlen = TB64ENCLEN(inlen); 
-    #ifdef __AVX__
+    #if defined(__AVX__) && !defined(NO_AVX)
   #define NE 64
     #else
   #define NE 32