From: Nathan Moinvaziri <nathan@nathanm.com>
Date: Thu, 28 Jan 2021 08:06:08 +0000 (-0800)
Subject: Store result of early exit trigger at the top of longest_match.
X-Git-Tag: v2.0.0-RC2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1617eb163ebecd4d462207f0ea380661b91ab09d;p=thirdparty%2Fzlib-ng.git

Store result of early exit trigger at the top of longest_match.
---

diff --git a/match_tpl.h b/match_tpl.h
index 7364fb7d..b15ca17b 100644
--- a/match_tpl.h
+++ b/match_tpl.h
@@ -37,6 +37,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) {
     Z_REGISTER unsigned char *mbase_end;
     const Pos *prev = s->prev;
     Pos limit;
+    int32_t early_exit;
     uint32_t chain_length, nice_match, best_len, offset;
     uint32_t lookahead = s->lookahead;
     bestcmp_t scan_end;
@@ -80,6 +81,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) {
 
     /* Do not waste too much time if we already have a good match */
     chain_length = s->max_chain_length;
+    early_exit = s->level < EARLY_EXIT_TRIGGER_LEVEL;
     if (best_len >= s->good_match)
         chain_length >>= 2;
     nice_match = (uint32_t)s->nice_match;
@@ -161,7 +163,7 @@ Z_INTERNAL uint32_t LONGEST_MATCH(deflate_state *const s, Pos cur_match) {
             scan_end0 = *(bestcmp_t *)(scan+offset+1);
 #endif
             mbase_end = (mbase_start+offset);
-        } else if (UNLIKELY(s->level < EARLY_EXIT_TRIGGER_LEVEL)) {
+        } else if (UNLIKELY(early_exit)) {
             /* The probability of finding a match later if we here is pretty low, so for
              * performance it's best to outright stop here for the lower compression levels
              */