2-byte last distance pre-check.

PiperOrigin-RevId: 990730191

c/enc/hash_longest_match_simd_opt_inc.h

diff --git a/c/enc/hash_longest_match_simd_opt_inc.h b/c/enc/hash_longest_match_simd_opt_inc.h
index df9aa66..9a51301 100644
--- a/c/enc/hash_longest_match_simd_opt_inc.h
+++ b/c/enc/hash_longest_match_simd_opt_inc.h
@@ -170,6 +170,9 @@
   out->len = 0;
   out->len_code_delta = 0;
 
+  if (best_len < 1) {
+    best_len = 1;
+  }
   /* Try last distance first. */
   for (i = 0; i < (size_t)self->num_last_distances_to_check_; ++i) {
     const size_t backward = (size_t)distance_cache[i];
@@ -186,7 +189,8 @@
       break;
     }
     if (prev_ix + best_len > ring_buffer_mask ||
-        data[cur_ix_masked + best_len] != data[prev_ix + best_len]) {
+        BrotliUnalignedRead16(&data[cur_ix_masked + best_len - 1]) !=
+            BrotliUnalignedRead16(&data[prev_ix + best_len - 1])) {
       continue;
     }
     {