[flang] Lower omp.workshare to other omp constructs

Author: ivanradanov

flang/include/flang/Optimizer/CMakeLists.txt

@@ -2,3 +2,4 @@ add_subdirectory(CodeGen)
 add_subdirectory(Dialect)
 add_subdirectory(HLFIR)
 add_subdirectory(Transforms)
+add_subdirectory(OpenMP)

flang/include/flang/Optimizer/OpenMP/CMakeLists.txt

@@ -0,0 +1,4 @@
+set(LLVM_TARGET_DEFINITIONS Passes.td)
+mlir_tablegen(Passes.h.inc -gen-pass-decls -name FlangOpenMP)
+
+add_public_tablegen_target(FlangOpenMPPassesIncGen)

flang/include/flang/Optimizer/OpenMP/Passes.h

@@ -0,0 +1,30 @@
+//===- Passes.h - OpenMP pass entry points ----------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This header declares OpenMP pass entry points.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_OPTIMIZER_OPENMP_PASSES_H
+#define FORTRAN_OPTIMIZER_OPENMP_PASSES_H
+
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Pass/PassRegistry.h"
+#include <memory>
+
+namespace flangomp {
+#define GEN_PASS_DECL
+#define GEN_PASS_REGISTRATION
+#include "flang/Optimizer/OpenMP/Passes.h.inc"
+
+bool shouldUseWorkshareLowering(mlir::Operation *op);
+
+} // namespace flangomp
+
+#endif // FORTRAN_OPTIMIZER_OPENMP_PASSES_H

flang/include/flang/Optimizer/OpenMP/Passes.td

@@ -0,0 +1,18 @@
+//===-- Passes.td - HLFIR pass definition file -------------*- tablegen -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FORTRAN_DIALECT_OPENMP_PASSES
+#define FORTRAN_DIALECT_OPENMP_PASSES
+
+include "mlir/Pass/PassBase.td"
+
+def LowerWorkshare : Pass<"lower-workshare"> {
+  let summary = "Lower workshare construct";
+}
+
+#endif //FORTRAN_DIALECT_OPENMP_PASSES

flang/include/flang/Tools/CLOptions.inc

@@ -17,6 +17,7 @@
 #include "mlir/Transforms/Passes.h"
 #include "flang/Optimizer/CodeGen/CodeGen.h"
 #include "flang/Optimizer/HLFIR/Passes.h"
+#include "flang/Optimizer/OpenMP/Passes.h"
 #include "flang/Optimizer/Transforms/Passes.h"
 #include "llvm/Passes/OptimizationLevel.h"
 #include "llvm/Support/CommandLine.h"
@@ -344,6 +345,7 @@ inline void createHLFIRToFIRPassPipeline(
   pm.addPass(hlfir::createLowerHLFIRIntrinsics());
   pm.addPass(hlfir::createBufferizeHLFIR());
   pm.addPass(hlfir::createConvertHLFIRtoFIR());
+  pm.addPass(flangomp::createLowerWorkshare());
 }
 
 /// Create a pass pipeline for handling certain OpenMP transformations needed

flang/lib/Frontend/CMakeLists.txt

@@ -38,6 +38,7 @@ add_flang_library(flangFrontend
   FIRTransforms
   HLFIRDialect
   HLFIRTransforms
+  FlangOpenMPTransforms
   MLIRTransforms
   MLIRBuiltinToLLVMIRTranslation
   MLIRLLVMToLLVMIRTranslation

flang/lib/Optimizer/CMakeLists.txt

@@ -5,3 +5,4 @@ add_subdirectory(HLFIR)
 add_subdirectory(Support)
 add_subdirectory(Transforms)
 add_subdirectory(Analysis)
+add_subdirectory(OpenMP)

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

@@ -26,12 +26,13 @@
 #include "flang/Optimizer/HLFIR/HLFIRDialect.h"
 #include "flang/Optimizer/HLFIR/HLFIROps.h"
 #include "flang/Optimizer/HLFIR/Passes.h"
+#include "flang/Optimizer/OpenMP/Passes.h"
+#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
 #include "mlir/IR/Dominance.h"
 #include "mlir/IR/PatternMatch.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassManager.h"
 #include "mlir/Transforms/DialectConversion.h"
-#include "mlir/Dialect/OpenMP/OpenMPDialect.h"
 #include "llvm/ADT/TypeSwitch.h"
 
 namespace hlfir {
@@ -792,7 +793,8 @@ struct ElementalOpConversion
     // Generate a loop nest looping around the fir.elemental shape and clone
     // fir.elemental region inside the inner loop.
     hlfir::LoopNest loopNest =
-        hlfir::genLoopNest(loc, builder, extents, !elemental.isOrdered());
+        hlfir::genLoopNest(loc, builder, extents, !elemental.isOrdered(),
+                           flangomp::shouldUseWorkshareLowering(elemental));
     auto insPt = builder.saveInsertionPoint();
     builder.setInsertionPointToStart(loopNest.body);
     auto yield = hlfir::inlineElementalOp(loc, builder, elemental,

flang/lib/Optimizer/OpenMP/CMakeLists.txt

@@ -0,0 +1,26 @@
+get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
+
+add_flang_library(FlangOpenMPTransforms
+  LowerWorkshare.cpp
+
+  DEPENDS
+  FIRDialect
+  FlangOpenMPPassesIncGen
+  ${dialect_libs}
+
+  LINK_LIBS
+  FIRAnalysis
+  FIRDialect
+  FIRBuilder
+  FIRDialectSupport
+  FIRSupport
+  FIRTransforms
+  HLFIRDialect
+  MLIRIR
+  ${dialect_libs}
+
+  LINK_COMPONENTS
+  AsmParser
+  AsmPrinter
+  Remarks
+)