Start migration of static analyzer to using the
implicit lvalue-to-rvalue casts that John McCall
recently introduced.  This causes a whole bunch
of logic in the analyzer for handling lvalues
to vanish.  It does, however, raise a few issues
in the analyzer w.r.t to modeling various constructs
(e.g., field accesses to compound literals).

The .c/.m analysis test cases that fail are
due to a missing lvalue-to-rvalue cast that
will get introduced into the AST.  The .cpp
failures were more than I could investigate in
one go, and the patch was already getting huge.
I have XFAILED some of these tests, and they
should obviously be further investigated.

Some highlights of this patch include:

- CFG no longer requires an lvalue bit for
  CFGElements
- StackFrameContext doesn't need an 'asLValue'
  flag
- The "VisitLValue" path from GRExprEngine has
  been eliminated.

Besides the test case failures (XFAILed), there
are surely other bugs that are fallout from
this change.

llvm-svn: 121960
diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp
index 1abfde2..b958580 100644
--- a/clang/lib/Analysis/ReachableCode.cpp
+++ b/clang/lib/Analysis/ReachableCode.cpp
@@ -42,6 +42,9 @@
   else
     return SourceLocation();
 
+  if (const Expr *Ex = dyn_cast<Expr>(S))
+    S = Ex->IgnoreParenImpCasts();
+
   switch (S->getStmtClass()) {
     case Expr::BinaryOperatorClass: {
       const BinaryOperator *BO = cast<BinaryOperator>(S);
@@ -101,9 +104,6 @@
       R1 = CE->getSubExpr()->getSourceRange();
       return CE->getTypeBeginLoc();
     }
-    case Expr::ImplicitCastExprClass:
-      ++sn;
-      goto top;
     case Stmt::CXXTryStmtClass: {
       return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc();
     }