[CPP-434] Initial version of query + test cases.

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

@@ -0,0 +1,38 @@
+// Signed-comparison tests
+
+/* 1. Signed-signed comparison.  The semantics are undefined. */
+bool cannotHoldAnother8(int n1) {
+    // clang 8.0.0 -O2: deleted (silently)
+    // gcc 9.2 -O2: deleted (silently)
+    // msvc 19.22 /O2: not deleted
+    return n1 + 8 < n1; // BAD
+}
+bool canHoldPreceding16(int n1) {
+	return n1 - 16 < n1;
+}
+
+/* 2. Signed comparison with a narrower unsigned type.  The narrower
+      type gets promoted to the (signed) larger type, and so the
+      semantics are undefined. */
+bool cannotHoldAnotherUShort(int n1, unsigned short delta) {
+    // clang 8.0.0 -O2: deleted (silently)
+    // gcc 9.2 -O2: deleted (silently)
+    // msvc 19.22 /O2: not deleted
+    return n1 + delta < n1; // BAD
+}
+bool canHoldPrecedingUShort(int n1, unsigned short delta) {
+	return n1 - delta < n1;
+}
+
+/* 3. Signed comparison with a non-narrower unsigned type.  The
+      signed type gets promoted to (a possibly wider) unsigned type,
+      and the resulting comparison is unsigned. */
+bool cannotHoldAnotherUInt(int n1, unsigned int delta) {
+    // clang 8.0.0 -O2: not deleted
+    // gcc 9.2 -O2: not deleted
+    // msvc 19.22 /O2: not deleted
+    return n1 + delta < n1; // GOOD
+}
+bool canHoldPrecedingUInt(int n1, unsigned int delta) {
+	return n1 - delta < n1;
+}

cpp/ql/test/query-tests/Likely Bugs/Arithmetic/SignedComparisons/SignedComparisons.qlref

@@ -0,0 +1 @@
+Likely Bugs/Arithmetic/SignedComparisons.ql