diff --git a/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp b/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
index 94c41aab2280..f383c42a1d45 100644
--- a/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenItaniumCXXABI.cpp
@@ -284,6 +284,12 @@ class CIRGenItaniumCXXABI : public cir::CIRGenCXXABI {
 
   void buildBadCastCall(CIRGenFunction &CGF, mlir::Location loc) override;
 
+  // The traditional clang CodeGen emits calls to `__dynamic_cast` directly into
+  // LLVM in the `emitDynamicCastCall` function. In CIR, `dynamic_cast`
+  // expressions are lowered to `cir.dyn_cast` ops instead of calls to runtime
+  // functions. So during CIRGen we don't need the `emitDynamicCastCall`
+  // function that clang CodeGen has.
+
   mlir::cir::DynamicCastInfoAttr
   buildDynamicCastInfo(CIRGenFunction &CGF, mlir::Location Loc,
                        QualType SrcRecordTy, QualType DestRecordTy) override;
diff --git a/clang/lib/CIR/Dialect/IR/MissingFeatures.h b/clang/lib/CIR/Dialect/IR/MissingFeatures.h
index b7ae4873ee1a..e21fc0e0b191 100644
--- a/clang/lib/CIR/Dialect/IR/MissingFeatures.h
+++ b/clang/lib/CIR/Dialect/IR/MissingFeatures.h
@@ -20,9 +20,13 @@ namespace cir {
 struct MissingFeatures {
   // C++ ABI support
   static bool cxxABI() { return false; }
+  static bool setCallingConv() { return false; }
+
+  // Address space related
+  static bool addressSpace() { return false; }
 
   // Sanitizers
-  static bool sanitizers() { return false; }
+  static bool buildTypeCheck() { return false; }
 };
 
 } // namespace cir
diff --git a/clang/lib/CIR/Dialect/Transforms/LoweringPrepareItaniumCXXABI.cpp b/clang/lib/CIR/Dialect/Transforms/LoweringPrepareItaniumCXXABI.cpp
index 1c9b1f1b5f8f..3619648056cc 100644
--- a/clang/lib/CIR/Dialect/Transforms/LoweringPrepareItaniumCXXABI.cpp
+++ b/clang/lib/CIR/Dialect/Transforms/LoweringPrepareItaniumCXXABI.cpp
@@ -39,6 +39,8 @@ LoweringPrepareCXXABI *LoweringPrepareCXXABI::createItaniumABI() {
 static void buildBadCastCall(CIRBaseBuilderTy &builder, mlir::Location loc,
                              mlir::FlatSymbolRefAttr badCastFuncRef) {
   // TODO(cir): set the calling convention to __cxa_bad_cast.
+  assert(!MissingFeatures::setCallingConv());
+
   builder.create<mlir::cir::CallOp>(loc, badCastFuncRef, mlir::ValueRange{});
   builder.create<mlir::cir::UnreachableOp>(loc);
   builder.clearInsertionPoint();
@@ -51,6 +53,8 @@ static mlir::Value buildDynamicCastAfterNullCheck(CIRBaseBuilderTy &builder,
   auto castInfo = op.getInfo().cast<mlir::cir::DynamicCastInfoAttr>();
 
   // TODO(cir): consider address space
+  assert(!MissingFeatures::addressSpace());
+
   auto srcPtr = builder.createBitcast(srcValue, builder.getVoidPtrTy());
   auto srcRtti = builder.getConstant(loc, castInfo.getSrcRtti());
   auto destRtti = builder.getConstant(loc, castInfo.getDestRtti());
@@ -58,7 +62,9 @@ static mlir::Value buildDynamicCastAfterNullCheck(CIRBaseBuilderTy &builder,
 
   auto dynCastFuncRef = castInfo.getRuntimeFunc();
   mlir::Value dynCastFuncArgs[4] = {srcPtr, srcRtti, destRtti, offsetHint};
+
   // TODO(cir): set the calling convention for __dynamic_cast.
+  assert(!MissingFeatures::setCallingConv());
   mlir::Value castedPtr =
       builder
           .create<mlir::cir::CallOp>(loc, dynCastFuncRef,
@@ -90,11 +96,7 @@ LoweringPrepareItaniumCXXABI::lowerDynamicCast(CIRBaseBuilderTy &builder,
   auto loc = op->getLoc();
   auto srcValue = op.getSrc();
 
-  // TODO: emit a sanitizer check.
-  // buildTypeCheck(
-  //   TCK_DynamicOperation, DCE->getExprLoc(),
-  //   ThisAddr.getPointer(), srcRecordTy)
-  assert(!MissingFeatures::sanitizers());
+  assert(!MissingFeatures::buildTypeCheck());
 
   if (op.isRefcast())
     return buildDynamicCastAfterNullCheck(builder, op);