Merge pull request #2033 from bimbashrestha/icc

[opt] Small icc level 1 compression speed gain using #pragma vector

lib/compress/zstd_fast.c

@@ -80,6 +80,13 @@ ZSTD_compressBlock_fast_generic(
     }
 
     /* Main Search Loop */
+#ifdef __INTEL_COMPILER
+    /* From intel 'The vector pragma indicates that the loop should be 
+     * vectorized if it is legal to do so'. Can be used together with 
+     * #pragma ivdep (but have opted to exclude that because intel 
+     * warns against using it).*/
+    #pragma vector always
+#endif
     while (ip1 < ilimit) {   /* < instead of <=, because check at ip0+2 */
         size_t mLength;
         BYTE const* ip2 = ip0 + 2;