[deadstore] False positive caused by exceptional cfg

Summary:
The title

Also notice that there is a duplication of an error.

Reviewed By: skcho

Differential Revision: D27426933

fbshipit-source-id: dbd2f861a

infer/tests/codetoanalyze/cpp/liveness/dead_stores.cpp

@@ -539,6 +539,20 @@ class Exceptions {
     return 3;
   }
 
+  int return_in_try_in_for_ok() {
+    constexpr int i1 = 3;
+    for (int i = 1;; ++i) {
+      try {
+        return maybe_throw();
+      } catch (const char* msg) {
+        if (i1 == i) {
+          return 2;
+        }
+      }
+    }
+    return 3;
+  }
+
   int read_in_catch_ok() {
     int x;
     try {

infer/tests/codetoanalyze/cpp/liveness/issues.exp

@@ -1,6 +1,8 @@
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::dead_in_catch_bad, 4, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::not_read_in_catch_bad, 3, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::read_only_in_catch_bad, 5, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
+codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::return_in_try_in_for_ok, 2, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
+codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::return_in_try_in_for_ok, 2, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::Exceptions::unreachable_catch_bad, 1, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::FP_assign_array_tricky2_ok, 3, DEAD_STORE, no_bucket, ERROR, [Write of unused value]
 codetoanalyze/cpp/liveness/dead_stores.cpp, dead_stores::binaryConditional_bad, 1, DEAD_STORE, no_bucket, ERROR, [Write of unused value]