Create Specialized SCMemcmpNZ() when the length can't be zero.

src/util-memcmp.h

@@ -365,14 +365,12 @@ static inline int SCMemcmpLowercase(const void *s1, const void *s2, size_t len)
 
 #include <ctype.h>
 
-static inline int SCMemcmp(const void *s1, const void *s2, size_t len)
+/* Compare to non-zero sequence of bytes. */
+static inline int SCMemcmpNZ(const void *s1, const void *s2, size_t len)
 {
     uint64_t b1, w1, aligned1;
     uint64_t b2, w2, aligned2;
 
-    if (len == 0)
-        return 0;
-
     /* Load aligned words containing the beginning of each string.
      * These loads don't trigger unaligned events.
      */
@@ -411,6 +409,13 @@ static inline int SCMemcmp(const void *s1, const void *s2, size_t len)
     return 0;
 }
 
+/* Compare two sequences of bytes. */
+static inline int SCMemcmp(const void *s1, const void *s2, size_t len)
+{
+    if (len == 0)
+        return 0;
+    return SCMemcmpNZ(s1, s2, len);
+}
 /** \brief Convert 8 characters to lower case using SIMD.
  *  \param Word containing the 8 bytes.
  *  \return Word containing 8-bytes each converted to lowercase.

src/util-mpm-ac-tile.c

@@ -1494,7 +1494,7 @@ int CheckMatch(SCACTileSearchCtx *ctx, PatternMatcherQueue *pmq,
         /* Double check case-sensitve match now. */
         if (patterns[k] & 0xFFFF0000) {
             uint16_t patlen = pattern_list[pindex].patlen;
-            if (SCMemcmp(pattern_list[pindex].cs, buf_offset - patlen, patlen) != 0) {
+            if (SCMemcmpNZ(pattern_list[pindex].cs, buf_offset - patlen, patlen) != 0) {
                 /* Case-sensitive match failed. */
                 continue;
             }