From: Nick Terrell <terrelln@fb.com>
Date: Tue, 4 May 2021 18:43:20 +0000 (-0700)
Subject: [easy] Rewrite rowHashLog computation
X-Git-Tag: v1.5.0^2~43^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1ffa80a09eec11ec098fa80da31c4fdfd3a8d134;p=thirdparty%2Fzstd.git

[easy] Rewrite rowHashLog computation

`ZSTD_highbit32(1u << x) == x` when it isn't undefined behavior.
---

diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index bf0a14888..197e8ed8a 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -1761,7 +1761,7 @@ ZSTD_reset_matchState(ZSTD_matchState_t* ms,
         {   /* Switch to 32-entry rows if searchLog is 5 (or more) */
             U32 const rowLog = cParams->searchLog < 5 ? 4 : 5;
             assert(cParams->hashLog > rowLog);
-            ms->rowHashLog = ZSTD_highbit32((U32)1 << (cParams->hashLog - rowLog));
+            ms->rowHashLog = cParams->hashLog - rowLog;
         }
     }