CGObjCMac - silence static analyzer dyn_cast<>/getAs<> null dereference warnings. NFCI.

The static analyzer is warning about potential null dereferences, but we should be able to use cast<>/castAs<> directly and if not assert will fire for us.

llvm-svn: 373520
diff --git a/clang/lib/CodeGen/CGObjCMac.cpp b/clang/lib/CodeGen/CGObjCMac.cpp
index 12880fe..2b92c4b 100644
--- a/clang/lib/CodeGen/CGObjCMac.cpp
+++ b/clang/lib/CodeGen/CGObjCMac.cpp
@@ -2517,14 +2517,12 @@
     }
 
     if (const ArrayType *Array = CGM.getContext().getAsArrayType(FQT)) {
-      const ConstantArrayType *CArray =
-        dyn_cast_or_null<ConstantArrayType>(Array);
+      auto *CArray = cast<ConstantArrayType>(Array);
       uint64_t ElCount = CArray->getSize().getZExtValue();
       assert(CArray && "only array with known element size is supported");
       FQT = CArray->getElementType();
       while (const ArrayType *Array = CGM.getContext().getAsArrayType(FQT)) {
-        const ConstantArrayType *CArray =
-          dyn_cast_or_null<ConstantArrayType>(Array);
+        auto *CArray = cast<ConstantArrayType>(Array);
         ElCount *= CArray->getSize().getZExtValue();
         FQT = CArray->getElementType();
       }
@@ -4902,7 +4900,7 @@
                                        const ObjCIvarDecl *Ivar,
                                        unsigned CVRQualifiers) {
   const ObjCInterfaceDecl *ID =
-    ObjectTy->getAs<ObjCObjectType>()->getInterface();
+    ObjectTy->castAs<ObjCObjectType>()->getInterface();
   return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers,
                                   EmitIvarOffset(CGF, ID, Ivar));
 }
@@ -7053,7 +7051,7 @@
                                                llvm::Value *BaseValue,
                                                const ObjCIvarDecl *Ivar,
                                                unsigned CVRQualifiers) {
-  ObjCInterfaceDecl *ID = ObjectTy->getAs<ObjCObjectType>()->getInterface();
+  ObjCInterfaceDecl *ID = ObjectTy->castAs<ObjCObjectType>()->getInterface();
   llvm::Value *Offset = EmitIvarOffset(CGF, ID, Ivar);
   return EmitValueForIvarAtOffset(CGF, ID, BaseValue, Ivar, CVRQualifiers,
                                   Offset);