[CPP-434] Narrow down query.

cpp/ql/test/query-tests/Likely Bugs/Arithmetic/SignedOverflowCheck/SignedOverflowCheck.cpp

@@ -27,3 +27,55 @@ bool cannotHoldAnotherUInt(int n1, unsigned int delta) {
     // msvc 19.22 /O2: not deleted
     return n1 + delta < n1; // GOOD
 }
+
+bool shortShort1(unsigned short n1, unsigned short delta) {
+    // clang 8.0.0 -O2: deleted
+    // gcc 9.2 -O2: deleted
+    // msvc 19.22 /O2: not deleted
+	return n1 + delta < n1; // BAD
+}
+
+bool shortShort2(unsigned short n1, unsigned short delta) {
+    // clang 8.0.0 -O2: not deleted
+    // gcc 9.2 -O2: not deleted
+    // msvc 19.22 /O2: not deleted
+	return (unsigned short)(n1 + delta) < n1; // GOOD
+}
+
+/* Distinguish `varname` from `ptr->varname` and `obj.varname` */
+struct N {
+	unsigned short n1;
+} n, *np;
+
+bool shortStruct1(unsigned short n1, unsigned short delta) {
+	return np->n1 + delta < n1; // GOOD
+}
+
+bool shortStruct1a(unsigned short n1, unsigned short delta) {
+	return n1 + delta < n.n1; // GOOD
+}
+
+bool shortStruct2(unsigned short n1, unsigned short delta) {
+	return (unsigned short)(n1 + delta) < n.n1; // GOOD
+}
+
+struct se {
+        short xPos;
+        short yPos;
+        short xSize;
+        short ySize;
+};
+
+extern se *getSo(void);
+
+bool func1(se *so) {
+	se *o = getSo();
+	if (so->xPos + so->xSize < o->xPos // GOOD
+	    || so->xPos > o->xPos + o->xSize) { // GOOD
+    	// clang 8.0.0 -O2: not deleted
+    	// gcc 9.2 -O2: not deleted
+    	// msvc 19.22 /O2: not deleted
+		return false;
+	}
+	return true;
+}

cpp/ql/test/query-tests/Likely Bugs/Arithmetic/SignedOverflowCheck/SignedOverflowCheck.expected

@@ -1,2 +1,3 @@
 | SignedOverflowCheck.cpp:8:12:8:22 | ... < ... | Testing for signed overflow may produce undefined results. |
 | SignedOverflowCheck.cpp:18:12:18:26 | ... < ... | Testing for signed overflow may produce undefined results. |
+| SignedOverflowCheck.cpp:35:9:35:23 | ... < ... | Testing for signed overflow may produce undefined results. |