--- src/jrd/SimilarToMatcher.h
+++ src/jrd/SimilarToMatcher.h
@@ -1455,7 +1455,7 @@
 		gds__log("%d, %s", state, debugText.c_str());
 #endif
 
-#define ENCODE_OP_STATE(op, state) ((op) | (state))
+#define ENCODE_OP_STATE(op, state) (+(op) | (state))
 
 		// Go directly to op and state with a single switch.