No semantic change: reuse stack variable in P2SH evaluation

src/script/interpreter.cpp

@@ -1107,21 +1107,24 @@ bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, unsigne
         if (!scriptSig.IsPushOnly())
             return set_error(serror, SCRIPT_ERR_SIG_PUSHONLY);
 
-        // stackCopy cannot be empty here, because if it was the
+        // Restore stack.
+        swap(stack, stackCopy);
+
+        // stack cannot be empty here, because if it was the
         // P2SH  HASH <> EQUAL  scriptPubKey would be evaluated with
         // an empty stack and the EvalScript above would return false.
-        assert(!stackCopy.empty());
+        assert(!stack.empty());
 
-        const valtype& pubKeySerialized = stackCopy.back();
+        const valtype& pubKeySerialized = stack.back();
         CScript pubKey2(pubKeySerialized.begin(), pubKeySerialized.end());
-        popstack(stackCopy);
+        popstack(stack);
 
-        if (!EvalScript(stackCopy, pubKey2, flags, checker, serror))
+        if (!EvalScript(stack, pubKey2, flags, checker, serror))
             // serror is set
             return false;
-        if (stackCopy.empty())
+        if (stack.empty())
             return set_error(serror, SCRIPT_ERR_EVAL_FALSE);
-        if (!CastToBool(stackCopy.back()))
+        if (!CastToBool(stack.back()))
             return set_error(serror, SCRIPT_ERR_EVAL_FALSE);
         else
             return set_success(serror);