Back-Edge Detection Fix

[chris.wailes]

Summary

This patch fixes a bug where state information for the Consumed analysis was being deleted incorrectly. This was occurring because the analysis was not detecting when all of a block's successors had been visited correctly. A test case is included that failed with the previous code and passes with the application of this patch.

[delesley]

LGTM. Released as r235051.

lib/Analysis/Consumed.cpp

                                                            CurrStates,
                                                            WarningsHandler);
             
-            if (BlockInfo.allBackEdgesVisited(*SI, CurrBlock))
+            if (BlockInfo.allBackEdgesVisited(CurrBlock, *SI))
               BlockInfo.discardInfo(*SI);
           } else {
             BlockInfo.addInfo(*SI, CurrStates, OwnershipTaken);

test/SemaCXX/warn-consumed-analysis.cpp

   *var0; // expected-warning {{invalid invocation of method 'operator*' on object 'var0' while it is in the 'consumed' state}}
 }
 
+// Tests if state information is correctly discarded for certain shapes of CFGs.
+void testSwitchGOTO(void) {
+  int a;
+
+  LABEL0:
+  switch (a)
+  case 0:
+    goto LABEL0;
+
+  goto LABEL0;
+}
+
 typedef const int*& IntegerPointerReference;
 void testIsRValueRefishAndCanonicalType(IntegerPointerReference a) {}