diff --git a/flang/include/flang/Optimizer/CodeGen/CGPasses.td b/flang/include/flang/Optimizer/CodeGen/CGPasses.td
--- a/flang/include/flang/Optimizer/CodeGen/CGPasses.td
+++ b/flang/include/flang/Optimizer/CodeGen/CGPasses.td
@@ -23,10 +23,7 @@
     will also convert ops in the standard and FIRCG dialects.
   }];
   let constructor = "::fir::createFIRToLLVMPass()";
-  let dependentDialects = [
-    "fir::FIROpsDialect", "fir::FIRCodeGenDialect", "mlir::BuiltinDialect",
-    "mlir::LLVM::LLVMDialect", "mlir::omp::OpenMPDialect"
-  ];
+  let dependentDialects = ["mlir::LLVM::LLVMDialect"];
 }
 
 def CodeGenRewrite : Pass<"cg-rewrite"> {
diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -44,9 +44,8 @@
     return *static_cast<fir::LLVMTypeConverter *>(this->getTypeConverter());
   }
 };
-} // namespace
 
-namespace {
+// Lower `fir.address_of` operation to `llvm.address_of` operation.
 struct AddrOfOpConversion : public FIROpConversion<fir::AddrOfOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -60,6 +59,7 @@
   }
 };
 
+/// Lower `fir.has_value` operation to `llvm.return` operation.
 struct HasValueOpConversion : public FIROpConversion<fir::HasValueOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -71,6 +71,9 @@
   }
 };
 
+/// Lower `fir.global` operation to `llvm.global` operation.
+/// `fir.insert_on_range` operations are replaced with constant dense attribute
+/// if they are applied on the full range.
 struct GlobalOpConversion : public FIROpConversion<fir::GlobalOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -133,6 +136,8 @@
     return true;
   }
 
+  // TODO: String comparaison should be avoided. Replace linkName with an
+  // enumeration.
   mlir::LLVM::Linkage convertLinkage(Optional<StringRef> optLinkage) const {
     if (optLinkage.hasValue()) {
       auto name = optLinkage.getValue();