MFC r261680:

Pull in r200899 from upstream clang trunk:

  Allow transformation of VariableArray to ConstantArray.

  In the following code:

     struct A { static const int sz; };
     template<class T> void f() { T arr[A::sz]; }

  the array 'arr' is represented as a variable size array in the template.
  If 'A::sz' gets value below in the translation unit, the array in
  instantiation can turn into constant size array.

  This change fixes PR18633.

  Differential Revision: http://llvm-reviews.chandlerc.com/D2688

This fixes "Assertion failed: (T::isKind(*this)), function castAs"
errors, which can occur when building the security/quantis port.

Reported by:	ale

contrib/llvm/tools/clang/lib/Sema/TreeTransform.h

@@ -3837,7 +3837,9 @@ TreeTransform<Derived>::TransformVariableArrayType(TypeLocBuilder &TLB,
       return QualType();
   }
 
-  VariableArrayTypeLoc NewTL = TLB.push<VariableArrayTypeLoc>(Result);
+  // We might have constant size array now, but fortunately it has the same
+  // location layout.
+  ArrayTypeLoc NewTL = TLB.push<ArrayTypeLoc>(Result);
   NewTL.setLBracketLoc(TL.getLBracketLoc());
   NewTL.setRBracketLoc(TL.getRBracketLoc());
   NewTL.setSizeExpr(Size);