diff --git a/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp b/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
index 06a906c..948fb97 100644
--- a/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
+++ b/sapfor/experts/Sapfor_2017/_src/CFGraph/RD_subst.cpp
@@ -1235,8 +1235,9 @@ bool isArgReaches(int decl_instr, SAPFOR::BasicBlock* decl_bb,
     if (RDs_for_arg.size() == 1)
     {
         const int rd = *RDs_for_arg.begin();
-        if (rd >= decl_bb->getInstructions().front()->getNumber() && rd < decl_instr)
-            return true;
+        if (rd >= decl_bb->getInstructions().front()->getNumber() && 
+            rd <= decl_bb->getInstructions().back()->getNumber())
+            return rd < decl_instr;
     }
 
     auto arg_in_from_decl_it = decl_bb->getRD_In().find(arg);