Index: deflate.c
===================================================================
--- deflate.c.orig
+++ deflate.c
@@ -1233,12 +1233,13 @@ local void lm_init (s)
  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
  * OUT assertion: the match length is not greater than s->lookahead.
  */
-local uInt longest_match(deflate_state *s, IPos cur_match) {
+local uInt longest_match(deflate_state *s, IPos pcur_match) {
+    ptrdiff_t cur_match = pcur_match; /* extend to pointer width */
     unsigned chain_length = s->max_chain_length;/* max hash chain length */
     register Bytef *scan = s->window + s->strstart; /* current string */
     register Bytef *match;                      /* matched string */
     register int len;                           /* length of current match */
-    int best_len = (int)s->prev_length;         /* best match length so far */
+    ptrdiff_t best_len = s->prev_length;              /* best match length so far */
     int nice_match = s->nice_match;             /* stop if match long enough */
     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
         s->strstart - (IPos)MAX_DIST(s) : NIL;
@@ -1256,12 +1257,12 @@ local uInt longest_match(s, cur_match)
      * Try with and without -DUNALIGNED_OK to check.
      */
     register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
-    register ush scan_start = *(ushf*)scan;
-    register ush scan_end   = *(ushf*)(scan + best_len - 1);
+    register uInt scan_start = *(ushf*)scan;
+    register uInt scan_end   = *(ushf*)(scan + best_len - 1);
 #else
     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
-    register Byte scan_end1  = scan[best_len - 1];
-    register Byte scan_end   = scan[best_len];
+    register uInt scan_end1  = scan[best_len - 1];
+    register uInt scan_end   = scan[best_len];
 #endif
 
     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.