[flang][HLFIR][NFC] Use tablegen to reduce assignment pass boilerplate (#93030)

This pass is module-level and then runs on all operations implementing
the ordered assignment interface. It should not matter which top-level
operation the assignment is inside of.

This commit removes some unnecessary boilerplate that we can generate
automatically with tablegen.

Author: tblah

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

@@ -25,7 +25,6 @@ namespace hlfir {
 std::unique_ptr<mlir::Pass> createConvertHLFIRtoFIRPass();
 std::unique_ptr<mlir::Pass> createBufferizeHLFIRPass();
 std::unique_ptr<mlir::Pass> createLowerHLFIRIntrinsicsPass();
-std::unique_ptr<mlir::Pass> createLowerHLFIROrderedAssignmentsPass();
 
 #define GEN_PASS_REGISTRATION
 #include "flang/Optimizer/HLFIR/Passes.h.inc"

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

@@ -34,7 +34,6 @@ def LowerHLFIRIntrinsics : Pass<"lower-hlfir-intrinsics", "::mlir::ModuleOp"> {
 
 def LowerHLFIROrderedAssignments : Pass<"lower-hlfir-ordered-assignments", "::mlir::ModuleOp"> {
   let summary = "Lower HLFIR ordered assignments like forall and where operations";
-  let constructor = "hlfir::createLowerHLFIROrderedAssignmentsPass()";
   let options = [
     Option<"tryFusingAssignments", "fuse-assignments",
            "bool", /*default=*/"false",

flang/include/flang/Tools/CLOptions.inc

@@ -327,7 +327,7 @@ inline void createHLFIRToFIRPassPipeline(
     addNestedPassToAllTopLevelOperations(
         pm, hlfir::createOptimizedBufferization);
   }
-  pm.addPass(hlfir::createLowerHLFIROrderedAssignmentsPass());
+  pm.addPass(hlfir::createLowerHLFIROrderedAssignments());
   pm.addPass(hlfir::createLowerHLFIRIntrinsicsPass());
   pm.addPass(hlfir::createBufferizeHLFIRPass());
   pm.addPass(hlfir::createConvertHLFIRtoFIRPass());

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

@@ -1383,6 +1383,9 @@ class LowerHLFIROrderedAssignments
     : public hlfir::impl::LowerHLFIROrderedAssignmentsBase<
           LowerHLFIROrderedAssignments> {
 public:
+  using LowerHLFIROrderedAssignmentsBase<
+      LowerHLFIROrderedAssignments>::LowerHLFIROrderedAssignmentsBase;
+
   void runOnOperation() override {
     // Running on a ModuleOp because this pass may generate FuncOp declaration
     // for runtime calls. This could be a FuncOp pass otherwise.
@@ -1409,7 +1412,3 @@ class LowerHLFIROrderedAssignments
   }
 };
 } // namespace
-
-std::unique_ptr<mlir::Pass> hlfir::createLowerHLFIROrderedAssignmentsPass() {
-  return std::make_unique<LowerHLFIROrderedAssignments>();
-}