Fix an out-of-bounds read when prefetching compound dictionary heads.

PiperOrigin-RevId: 993852125

c/enc/backward_references_opt_inc.h

diff --git a/c/enc/backward_references_opt_inc.h b/c/enc/backward_references_opt_inc.h
index 149b43a..3ad6755 100644
--- a/c/enc/backward_references_opt_inc.h
+++ b/c/enc/backward_references_opt_inc.h
@@ -215,7 +215,7 @@
            dictionary heads[] line before the StoreRange loop. */
         if (ENABLE_COMPOUND_DICTIONARY) {
           PrefetchCompoundDictionaryHeadsOpt(&params->dictionary.compound,
-              ringbuffer, ringbuffer_mask, position + sr.len);
+              ringbuffer, ringbuffer_mask, range_end);
         }
         FN(StoreRange)(privat, ringbuffer, ringbuffer_mask, range_start,
                        range_end);