diff --git a/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp b/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
index 387b142..06a906c 100644
--- a/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
+++ b/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
@@ -1287,7 +1287,7 @@ bool isArgReaches(int decl_instr, SAPFOR::BasicBlock* decl_bb,
 
     reachable = banned_blocks;
     worklist = reachable;
-    while (worklist.size() != 0 || banned_instructions.size() == 0)
+    while (worklist.size() != 0 && banned_instructions.size() != 0)
     {
         if(worklist.find(dest_bb) != worklist.end())
             return false;