add some comments

Author: seven-mile

clang/lib/CIR/CodeGen/CIRGenBuilder.h

@@ -417,6 +417,7 @@ class CIRGenBuilderTy : public CIRBaseBuilderTy {
 
   // Fetch the type representing a pointer to unsigned int values.
   mlir::cir::PointerType getUInt8PtrTy(unsigned AddrSpace = 0) {
+    // If zero address space, it's already cached.
     if (AddrSpace == 0)
       return typeCache.UInt8PtrTy;
     return mlir::cir::PointerType::get(getContext(), typeCache.UInt8Ty,

clang/lib/CIR/Dialect/Transforms/LoweringPrepare.cpp

@@ -526,6 +526,7 @@ static void lowerArrayDtorCtorIntoLoop(CIRBaseBuilderTy &builder,
   mlir::Value end = builder.create<mlir::cir::PtrStrideOp>(
       loc, eltTy, begin, numArrayElementsConst);
 
+  // TODO: fix getPointerTo(eltTy) by querying the data layout
   assert(!::cir::MissingFeatures::addressSpaceInAlloca());
   auto tmpAddr = builder.createAlloca(
       loc, /*addr type*/ builder.getPointerTo(eltTy),