From: Yann Collet <cyan@fb.com>
Date: Wed, 16 Oct 2024 00:46:01 +0000 (-0700)
Subject: small dictionary compression speed improvement
X-Git-Tag: v1.5.7^2~74^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e63896eb5844cb246aad7959ab208aa0a8f152bd;p=thirdparty%2Fzstd.git

small dictionary compression speed improvement

not as good as small-blocks improvement,
but generally positive.
---

diff --git a/lib/compress/zstd_fast.c b/lib/compress/zstd_fast.c
index e7edf9490..5373e3640 100644
--- a/lib/compress/zstd_fast.c
+++ b/lib/compress/zstd_fast.c
@@ -597,8 +597,8 @@ size_t ZSTD_compressBlock_fast_dictMatchState_generic(
                 }
             }
 
-            if (matchIndex > prefixStartIndex && MEM_read32(match) == MEM_read32(ip0)) {
-                /* found a regular match */
+            if (ZSTD_match4Found_cmov(ip0, match, matchIndex, prefixStartIndex)) {
+                /* found a regular match of size >= 4 */
                 U32 const offset = (U32) (ip0 - match);
                 mLength = ZSTD_count(ip0 + 4, match + 4, iend) + 4;
                 while (((ip0 > anchor) & (match > prefixStart))