Added a path-sensitive idempotent operation checker (-analyzer-idempotent-operation). Finds idempotent and/or tautological operations in a path sensitive context, flagging operations that have no effect or a predictable effect.

Example:
{
int a = 1;
int b = 5;
int c = b / a; // a is 1 on all paths
}

- New IdempotentOperationChecker class
- Moved recursive Stmt functions in r107675 to IdempotentOperationChecker
- Minor refactoring of SVal to allow checking for any integer
- Added command line option for check
- Added basic test cases

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107706 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/AnalysisConsumer.cpp b/lib/Checker/AnalysisConsumer.cpp
index 7c5f8ca..35f5eec 100644
--- a/lib/Checker/AnalysisConsumer.cpp
+++ b/lib/Checker/AnalysisConsumer.cpp
@@ -28,6 +28,7 @@
 #include "clang/Checker/PathSensitive/GRExprEngine.h"
 #include "clang/Checker/PathSensitive/GRTransferFuncs.h"
 #include "clang/Checker/PathDiagnosticClients.h"
+#include "GRExprEngineExperimentalChecks.h"
 #include "clang/Basic/FileManager.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Frontend/AnalyzerOptions.h"
@@ -340,6 +341,9 @@
   if (C.Opts.EnableExperimentalChecks)
     RegisterExperimentalChecks(Eng);
 
+  if (C.Opts.EnableIdempotentOperationChecker)
+    RegisterIdempotentOperationChecker(Eng);
+
   // Set the graph auditor.
   llvm::OwningPtr<ExplodedNode::Auditor> Auditor;
   if (mgr.shouldVisualizeUbigraph()) {