diff --git a/target-mips/helper.h b/target-mips/helper.h
index e446578377..b8ec15eab2 100644
--- a/target-mips/helper.h
+++ b/target-mips/helper.h
@@ -15,11 +15,11 @@ DEF_HELPER_3(lwr, tl, tl, tl, int)
 DEF_HELPER_3(swl, void, tl, tl, int)
 DEF_HELPER_3(swr, void, tl, tl, int)
 
-DEF_HELPER_1(clo, tl, tl)
-DEF_HELPER_1(clz, tl, tl)
+DEF_HELPER_FLAGS_1(clo, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
+DEF_HELPER_FLAGS_1(clz, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
 #ifdef TARGET_MIPS64
-DEF_HELPER_1(dclo, tl, tl)
-DEF_HELPER_1(dclz, tl, tl)
+DEF_HELPER_FLAGS_1(dclo, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
+DEF_HELPER_FLAGS_1(dclz, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
 DEF_HELPER_2(dmult, void, tl, tl)
 DEF_HELPER_2(dmultu, void, tl, tl)
 #endif