[PATCH 3/3] xdiff: simplify comparison

From: Phillip Wood via GitGitGadget <gitgitgadget@gmail.com>
Date: Nov 17, 2021, 11:20 UTC
Message-ID: <b0bc773f51e114d96ad6efd1ebd03fb6e7646288.1637148025.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.1079.git.1637148025.gitgitgadget@gmail.com>

From: Phillip Wood <phillip.wood@dunelm.org.uk>

Now that the histogram algorithm calls xdl_classify_record() it is no longer necessary to use xdl_recmatch() to compare lines, it is sufficient just to compare the hash values. This has a negligible effect on performance.

Test HEAD~1 HEAD ----------------------------------------------------------------------------- 4000.1: log -3000 (baseline) 0.19(0.12+0.07) 0.18(0.14+0.04) -5.3% 4000.2: log --raw -3000 (tree-only) 0.98(0.81+0.16) 0.98(0.79+0.18) +0.0% 4000.3: log -p -3000 (Myers) 4.81(4.23+0.56) 4.80(4.26+0.53) -0.2% 4000.4: log -p -3000 --histogram 5.83(5.11+0.70) 5.82(5.15+0.65) -0.2% 4000.5: log -p -3000 --patience 5.31(4.61+0.69) 5.30(4.54+0.75) -0.2%

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
---
 xdiff/xdiffi.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index a4542c05b61..6a3b9280beb 100644
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -392,10 +392,7 @@ static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1,
 
 static int recs_match(xrecord_t *rec1, xrecord_t *rec2, long flags)
 {
-	return (rec1->ha == rec2->ha &&
-		xdl_recmatch(rec1->ptr, rec1->size,
-			     rec2->ptr, rec2->size,
-			     flags));
+	return (rec1->ha == rec2->ha);
 }
 
 /*

-- 
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