From 6bfc370b193f5b757268a9bc1ed84a993db39794 Mon Sep 17 00:00:00 2001
From: Felix Hanau <hanau2@illinois.edu>
Date: Sat, 3 Dec 2022 22:05:02 -0800
Subject: [PATCH] Unroll longest_match() inner loop

---
 deflate.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/deflate.c b/deflate.c
index f06f1784f..85ffa0483 100644
--- a/deflate.c
+++ b/deflate.c
@@ -1266,12 +1266,20 @@ static uint32_t longest_match(s, cur_match)
             if (xor) {
                 int match_byte = __builtin_ctzl(xor) / 8;
                 scan += match_byte;
-                match += match_byte;
                 break;
-            } else {
-                scan += 8;
-                match += 8;
             }
+            scan += 8;
+            match += 8;
+            sv = *(uint64_t*)(void*)scan;
+            mv = *(uint64_t*)(void*)match;
+            xor = sv ^ mv;
+            if (xor) {
+                int match_byte = __builtin_ctzl(xor) / 8;
+                scan += match_byte;
+                break;
+            }
+            scan += 8;
+            match += 8;
         } while (scan < strend);
 
         if (scan > strend)