[flang][HLFIR][NFC] Reduce HLFIR to FIR conversion boilerplate (#93539)

The pass constructor can be generated automatically.

This pass is module-level and then runs on all relevant intrinsic
operations inside of the module, no matter what top level operation they
are inside of.

Author: tblah

flang/include/flang/Optimizer/HLFIR/Passes.h

@@ -20,10 +20,6 @@
 
 namespace hlfir {
 #define GEN_PASS_DECL
-#include "flang/Optimizer/HLFIR/Passes.h.inc"
-
-std::unique_ptr<mlir::Pass> createConvertHLFIRtoFIRPass();
-
 #define GEN_PASS_REGISTRATION
 #include "flang/Optimizer/HLFIR/Passes.h.inc"
 } // namespace hlfir

flang/include/flang/Optimizer/HLFIR/Passes.td

@@ -12,7 +12,6 @@
 include "mlir/Pass/PassBase.td"
 def ConvertHLFIRtoFIR : Pass<"convert-hlfir-to-fir", "::mlir::ModuleOp"> {
   let summary = "Lower High-Level FIR to FIR";
-  let constructor = "hlfir::createConvertHLFIRtoFIRPass()";
   let dependentDialects = [
     "mlir::func::FuncDialect",
   ];

flang/include/flang/Tools/CLOptions.inc

@@ -331,7 +331,7 @@ inline void createHLFIRToFIRPassPipeline(
   pm.addPass(hlfir::createLowerHLFIROrderedAssignments());
   pm.addPass(hlfir::createLowerHLFIRIntrinsics());
   pm.addPass(hlfir::createBufferizeHLFIR());
-  pm.addPass(hlfir::createConvertHLFIRtoFIRPass());
+  pm.addPass(hlfir::createConvertHLFIRtoFIR());
 }
 
 /// Create a pass pipeline for handling certain OpenMP transformations needed

flang/lib/Optimizer/HLFIR/Transforms/ConvertToFIR.cpp

@@ -789,7 +789,3 @@ class ConvertHLFIRtoFIR
 };
 
 } // namespace
-
-std::unique_ptr<mlir::Pass> hlfir::createConvertHLFIRtoFIRPass() {
-  return std::make_unique<ConvertHLFIRtoFIR>();
-}