diff --git a/CMakeLists.txt b/CMakeLists.txt
index f2bcf1c..797b76f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,7 +24,7 @@ set(SOURCE_FILES
         tunnel_server.cpp
         my_ev.cpp
 )
-set(CMAKE_CXX_FLAGS "-Wall -Wextra -Wno-unused-variable -Wno-unused-parameter -Wno-missing-field-initializers -O2 -g -fsanitize=address,undefined")
+set(CMAKE_CXX_FLAGS "-Wall -Wextra -Wno-unused-variable -Wno-unused-parameter -Wno-missing-field-initializers -O2 -g -fsanitize=address,undefined -fno-sanitize=shift")
 
 #target_include_directories(speederv2 PRIVATE .)
 #set(CMAKE_LINK_LIBRARY_FLAG "-lrt")
diff --git a/common.cpp b/common.cpp
index c36293d..d43884e 100644
--- a/common.cpp
+++ b/common.cpp
@@ -896,7 +896,7 @@ u32_t djb2(unsigned char *str, int len) {
     u32_t hash = 5381;
     int c;
     int i = 0;
-    while (c = *str++, i++ != len) {
+    while (c = *str++, ++i != len) {
         hash = ((hash << 5) + hash) ^ c; /* (hash * 33) ^ c */
     }
 
@@ -908,7 +908,7 @@ u32_t sdbm(unsigned char *str, int len) {
     u32_t hash = 0;
     int c;
     int i = 0;
-    while (c = *str++, i++ != len) {
+    while (c = *str++, ++i != len) {
         hash = c + (hash << 6) + (hash << 16) - hash;
     }
     // hash=htonl(hash);