[fir] Sync back after D112845

Author: clementval

flang/include/flang/Optimizer/CodeGen/CGPasses.td

@@ -23,10 +23,7 @@ def FIRToLLVMLowering : Pass<"fir-to-llvm-ir", "mlir::ModuleOp"> {
     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", "mlir::ModuleOp"> {

flang/lib/Optimizer/CodeGen/CodeGen.cpp

@@ -309,6 +309,7 @@ static void createGlobal(mlir::Location loc, mlir::ModuleOp mod, StringRef name,
 }
 
 namespace {
+/// Lower `fir.address_of` operation to `llvm.address_of` operation.
 struct AddrOfOpConversion : public FIROpConversion<fir::AddrOfOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -2447,6 +2448,7 @@ struct GlobalLenOpConversion : public FIROpConversion<fir::GlobalLenOp> {
   }
 };
 
+/// Lower `fir.has_value` operation to `llvm.return` operation.
 struct HasValueOpConversion : public FIROpConversion<fir::HasValueOp> {
   using FIROpConversion::FIROpConversion;
 
@@ -2458,6 +2460,9 @@ struct HasValueOpConversion : public FIROpConversion<fir::HasValueOp> {
   }
 };
 
+/// 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;
 
@@ -2520,6 +2525,8 @@ struct GlobalOpConversion : public FIROpConversion<fir::GlobalOp> {
     return true;
   }
 
+  // TODO: String comparison should be avoided. Replace linkName with an
+  // enumeration.
   mlir::LLVM::Linkage convertLinkage(Optional<StringRef> optLinkage) const {
     if (optLinkage.hasValue()) {
       auto name = optLinkage.getValue();