C++: Add a testcase that was discussed during PR reviews.

Author: MathiasVP

cpp/ql/test/library-tests/controlflow/guards/Guards.expected

@@ -49,3 +49,5 @@
 | test.cpp:135:6:135:21 | call to __builtin_expect |
 | test.cpp:141:6:141:21 | call to __builtin_expect |
 | test.cpp:145:6:145:21 | call to __builtin_expect |
+| test.cpp:151:6:151:14 | ! ... |
+| test.cpp:151:8:151:13 | ... + ... |

cpp/ql/test/library-tests/controlflow/guards/GuardsCompare.expected

@@ -267,6 +267,16 @@
 | 146 | x != 0 when ! ... is false |
 | 146 | x != 0 when x is true |
 | 146 | x == 0 when x is false |
+| 151 | ! ... != 0 when ! ... is true |
+| 151 | ! ... == 0 when ! ... is false |
+| 151 | ... + ... != 0 when ! ... is false |
+| 151 | ... + ... != 0 when ... + ... is true |
+| 151 | ... + ... == 0 when ! ... is true |
+| 151 | ... + ... == 0 when ... + ... is false |
+| 151 | a != -10 when ! ... is false |
+| 151 | a != -10 when ... + ... is true |
+| 151 | a == -10 when ! ... is true |
+| 151 | a == -10 when ... + ... is false |
 | 152 | p != 0 when p is true |
 | 152 | p == 0 when p is false |
 | 158 | ! ... != 0 when ! ... is true |

cpp/ql/test/library-tests/controlflow/guards/GuardsControl.expected

@@ -108,3 +108,5 @@
 | test.cpp:135:6:135:21 | call to __builtin_expect | true | 135 | 136 |
 | test.cpp:141:6:141:21 | call to __builtin_expect | true | 141 | 142 |
 | test.cpp:145:6:145:21 | call to __builtin_expect | true | 145 | 146 |
+| test.cpp:151:6:151:14 | ! ... | true | 151 | 152 |
+| test.cpp:151:8:151:13 | ... + ... | false | 151 | 152 |

cpp/ql/test/library-tests/controlflow/guards/GuardsEnsure.expected

@@ -399,3 +399,8 @@ unary
 | test.cpp:145:6:145:21 | call to __builtin_expect | test.cpp:145:6:145:21 | call to __builtin_expect | != | 0 | 145 | 146 |
 | test.cpp:145:6:145:21 | call to __builtin_expect | test.cpp:145:23:145:23 | a | != | 42 | 145 | 146 |
 | test.cpp:145:6:145:21 | call to __builtin_expect | test.cpp:145:23:145:29 | ... != ... | != | 0 | 145 | 146 |
+| test.cpp:151:6:151:14 | ! ... | test.cpp:151:6:151:14 | ! ... | != | 0 | 151 | 152 |
+| test.cpp:151:6:151:14 | ! ... | test.cpp:151:8:151:8 | a | == | -10 | 151 | 152 |
+| test.cpp:151:6:151:14 | ! ... | test.cpp:151:8:151:13 | ... + ... | == | 0 | 151 | 152 |
+| test.cpp:151:8:151:13 | ... + ... | test.cpp:151:8:151:8 | a | == | -10 | 151 | 152 |
+| test.cpp:151:8:151:13 | ... + ... | test.cpp:151:8:151:13 | ... + ... | == | 0 | 151 | 152 |

cpp/ql/test/library-tests/controlflow/guards/test.cpp

@@ -145,4 +145,10 @@ void unary_test_builtin_expected(int a) {
   if(__builtin_expect(a != 42, 0)) {
       use(a);
   }
+}
+
+void addition_and_negation(int a) {
+  if(!(a + 10)) {
+    use(a); // a is -10 here
+  }
 }