CGBlocks - silence static analyzer getAs<> null dereference warnings. NFCI.

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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@373752 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGBlocks.cpp

@@ -1253,8 +1253,7 @@ llvm::Type *CodeGenModule::getGenericBlockLiteralType() {
 
 RValue CodeGenFunction::EmitBlockCallExpr(const CallExpr *E,
                                           ReturnValueSlot ReturnValue) {
-  const BlockPointerType *BPT =
-    E->getCallee()->getType()->getAs<BlockPointerType>();
+  const auto *BPT = E->getCallee()->getType()->castAs<BlockPointerType>();
   llvm::Value *BlockPtr = EmitScalarExpr(E->getCallee());
   llvm::Type *GenBlockTy = CGM.getGenericBlockLiteralType();
   llvm::Value *Func = nullptr;
@@ -1802,7 +1801,7 @@ struct CallBlockRelease final : EHScopeStack::Cleanup {
 bool CodeGenFunction::cxxDestructorCanThrow(QualType T) {
   if (const auto *RD = T->getAsCXXRecordDecl())
     if (const CXXDestructorDecl *DD = RD->getDestructor())
-      return DD->getType()->getAs<FunctionProtoType>()->canThrow();
+      return DD->getType()->castAs<FunctionProtoType>()->canThrow();
   return false;
 }