C++: Add pointer/pointee conflation test.

Author: MathiasVP

cpp/ql/test/library-tests/dataflow/dataflow-tests/dataflow-consistency.expected

@@ -185,6 +185,8 @@ postWithInFlow
 | test.cpp:1138:5:1138:8 | data [inner post update] | PostUpdateNode should not be the target of local flow. |
 | test.cpp:1139:3:1139:7 | * ... [post update] | PostUpdateNode should not be the target of local flow. |
 | test.cpp:1139:4:1139:7 | data [inner post update] | PostUpdateNode should not be the target of local flow. |
+| test.cpp:1153:5:1153:6 | * ... [post update] | PostUpdateNode should not be the target of local flow. |
+| test.cpp:1153:6:1153:6 | p [inner post update] | PostUpdateNode should not be the target of local flow. |
 viableImplInCallContextTooLarge
 uniqueParameterNodeAtPosition
 uniqueParameterNodePosition

cpp/ql/test/library-tests/dataflow/dataflow-tests/test-source-sink.expected

@@ -327,6 +327,7 @@ irFlow
 | test.cpp:1117:27:1117:34 | call to source | test.cpp:1117:27:1117:34 | call to source |
 | test.cpp:1132:11:1132:16 | call to source | test.cpp:1121:8:1121:8 | x |
 | test.cpp:1138:17:1138:22 | call to source | test.cpp:1140:8:1140:18 | * ... |
+| test.cpp:1153:10:1153:15 | call to source | test.cpp:1148:10:1148:12 | * ... |
 | true_upon_entry.cpp:9:11:9:16 | call to source | true_upon_entry.cpp:13:8:13:8 | x |
 | true_upon_entry.cpp:17:11:17:16 | call to source | true_upon_entry.cpp:21:8:21:8 | x |
 | true_upon_entry.cpp:27:9:27:14 | call to source | true_upon_entry.cpp:29:8:29:8 | x |

cpp/ql/test/library-tests/dataflow/dataflow-tests/test.cpp

@@ -1138,4 +1138,19 @@ void test_uncertain_array(int n1, int n2) {
   *(data + 1) = source();
   *data = 0;
   sink(*(data + 1)); // $ ast=1138:17 ast=1137:7 ir
+}
+
+namespace conflation_regression {
+
+  char* source(int);
+
+  void read_deref_deref(char **l) { // $ ast-def=l ir-def=*l ir-def=**l
+    sink(**l); // $ SPURIOUS: ir
+  }
+
+  void f(char ** p) // $ ast-def=p ir-def=*p ir-def=**p
+  {
+    *p = source(0);
+    read_deref_deref(p);
+  }
 }