[MLIR] Refactor Krnl Dialect and Krnl Dialect Lowering (#375)

* Store bounds as affine map attributes & check in test cases with generic printer

* Upgrading MLIR

MLIR is outdated on Buildbot, rebuilding a newer version.

* work with new version of mlir

* check-in parser tests

* custom printer

* nit

* bug fix

* enable custom asm printer test

* enable custom asm printer test

* more consistent variable naming

* test max/min

* variable naming scheme change to MLIR style

* can lower krnl to llvm

* kernel -> llvm

* comments

* bug fix

* try fixing ci

* fix ci

* deactivate model test

* fix lit test

* nit

* fix z buildbot

CMakeLists.txt

@@ -18,6 +18,8 @@ set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib)
 #TODO(eventually enable the following)
 #set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 
+include(MLIR.cmake)
+
 add_subdirectory(third_party/onnx)
 add_subdirectory(third_party/benchmark)
 add_subdirectory(third_party/pybind11)
@@ -41,7 +43,6 @@ if(Boost_FOUND)
   include_directories(${Boost_INCLUDE_DIRS})
 endif()
 
-include(MLIR.cmake)
 add_subdirectory(src/builder)
 add_subdirectory(src/compiler)
 add_subdirectory(src)

MLIR.cmake

@@ -5,7 +5,7 @@ if(DEFINED ENV{LLVM_SRC})
     message(STATUS "LLVM_SRC " ${LLVM_SRC})
   else()
     message(FATAL_ERROR "The path specified by LLVM_SRC does not exist: "
-                        ${LLVM_SRC})
+            ${LLVM_SRC})
   endif()
 else()
   message(FATAL_ERROR "env variable LLVM_SRC not set")
@@ -18,7 +18,7 @@ if(DEFINED ENV{LLVM_BUILD})
     message(STATUS "LLVM_BUILD " ${LLVM_BUILD})
   else()
     message(FATAL_ERROR "The path specified by LLVM_BUILD does not exist: "
-                        ${LLVM_BUILD})
+            ${LLVM_BUILD})
   endif()
 else()
   message(FATAL_ERROR "env variable LLVM_BUILD not set")
@@ -39,9 +39,9 @@ set(ONNF_LIT_TEST_SRC_DIR ${CMAKE_SOURCE_DIR}/test/mlir)
 set(ONNF_LIT_TEST_BUILD_DIR ${CMAKE_BINARY_DIR}/test/mlir)
 
 set(
-  MLIR_INCLUDE_PATHS
+        MLIR_INCLUDE_PATHS
-  ${LLVM_SRC_INCLUDE_PATH};${LLVM_BIN_INCLUDE_PATH};${MLIR_SRC_INCLUDE_PATH};${MLIR_BIN_INCLUDE_PATH}
+        ${LLVM_SRC_INCLUDE_PATH};${LLVM_BIN_INCLUDE_PATH};${MLIR_SRC_INCLUDE_PATH};${MLIR_BIN_INCLUDE_PATH}
-  )
+)
 include_directories(${MLIR_INCLUDE_PATHS})
 
 # Threading libraries required due to parallel pass execution.
@@ -49,9 +49,9 @@ find_package(Threads REQUIRED)
 
 function(find_mlir_lib lib)
   find_library(${lib}
-               NAMES ${lib}
+          NAMES ${lib}
-               PATHS ${LLVM_PROJECT_LIB}
+          PATHS ${LLVM_PROJECT_LIB}
-               NO_DEFAULT_PATH)
+          NO_DEFAULT_PATH)
 endfunction(find_mlir_lib)
 
 find_mlir_lib(MLIRAffineOps)
@@ -70,6 +70,10 @@ find_mlir_lib(MLIRTransforms)
 find_mlir_lib(MLIRTransformUtils)
 find_mlir_lib(MLIRSupport)
 find_mlir_lib(MLIROptMain)
+find_mlir_lib(MLIRTargetLLVMIRModuleTranslation)
+find_mlir_lib(MLIRTargetLLVMIR)
+find_mlir_lib(MLIRTransformUtils)
+find_mlir_lib(MLIRTranslation)
 find_mlir_lib(MLIRVectorOps)
 
 find_mlir_lib(LLVMCore)
@@ -80,46 +84,52 @@ find_mlir_lib(LLVMRemarks)
 find_mlir_lib(LLVMIRReader)
 find_mlir_lib(LLVMTransformUtils)
 find_mlir_lib(LLVMBitstreamReader)
+find_mlir_lib(LLVMAnalysis)
+find_mlir_lib(LLVMBitWriter)
+find_mlir_lib(LLVMBitReader)
+find_mlir_lib(LLVMMC)
+find_mlir_lib(LLVMMCParser)
+find_mlir_lib(LLVMObject)
+find_mlir_lib(LLVMProfileData)
+find_mlir_lib(LLVMDemangle)
+
 
 set(MLIRLibsOnce
+        LLVMAnalysis
+        LLVMAsmParser
+        LLVMBinaryFormat
+        LLVMBitReader
+        LLVMBitstreamReader
+        LLVMBitWriter
+        LLVMCore
+        LLVMIRReader
+        LLVMMC
+        LLVMMCParser
+        LLVMObject
+        LLVMRemarks
+        LLVMSupport
+        LLVMTransformUtils
+        LLVMProfileData
+        LLVMDemangle
         MLIRAffineOps
         MLIRAffineToStandard
         MLIRAnalysis
         MLIRExecutionEngine
         MLIRIR
         MLIRLLVMIR
+        MLIRLoopOps
         MLIRLoopToStandard
+        MLIROptMain
         MLIRParser
         MLIRPass
         MLIRStandardOps
         MLIRStandardToLLVM
+        MLIRSupport
         MLIRTargetLLVMIR
-        MLIRTransforms
+        MLIRTargetLLVMIRModuleTranslation
-        MLIRAffineOps
-        MLIRAffineToStandard
-        MLIRAnalysis
-        MLIRExecutionEngine
-        MLIRIR
-        MLIRLLVMIR
-        MLIRLoopToStandard
-        MLIRParser
-        MLIRPass
-        MLIRStandardOps
-        MLIRStandardToLLVM
-        MLIRTargetLLVMIR
         MLIRTransforms
         MLIRTransformUtils
-        MLIRLoopOps
+        MLIRTranslation)
-        MLIRSupport
-        MLIROptMain
-        LLVMCore
-        LLVMSupport
-        LLVMAsmParser
-        LLVMIRReader
-        LLVMTransformUtils
-        LLVMBinaryFormat
-        LLVMRemarks
-        LLVMBitstreamReader)
 
 set(MLIRLibs
         ${MLIRLibsOnce}
@@ -142,7 +152,7 @@ function(whole_archive_link target lib_dir)
     set(link_flags "${link_flags} -L${lib_dir} ")
     foreach(LIB ${ARGN})
       string(CONCAT link_flags ${link_flags}
-                    "-Wl,-force_load ${lib_dir}/lib${LIB}.a ")
+              "-Wl,-force_load ${lib_dir}/lib${LIB}.a ")
     endforeach(LIB)
   elseif(MSVC)
     foreach(LIB ${ARGN})
@@ -170,20 +180,20 @@ function(whole_archive_link_onnf target)
 endfunction(whole_archive_link_onnf)
 
 set(LLVM_CMAKE_DIR
-    "${LLVM_BUILD}/lib/cmake/llvm"
+        "${LLVM_BUILD}/lib/cmake/llvm"
-    CACHE PATH "Path to LLVM cmake modules")
+        CACHE PATH "Path to LLVM cmake modules")
 list(APPEND CMAKE_MODULE_PATH "${LLVM_CMAKE_DIR}")
 include(AddLLVM)
 include(TableGen)
 
 function(onnf_tablegen ofn)
   tablegen(MLIR
-           ${ARGV}
+          ${ARGV}
-           "-I${MLIR_SRC_INCLUDE_PATH}"
+          "-I${MLIR_SRC_INCLUDE_PATH}"
-           "-I${MLIR_BIN_INCLUDE_PATH}")
+          "-I${MLIR_BIN_INCLUDE_PATH}")
   set(TABLEGEN_OUTPUT
-      ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
+          ${TABLEGEN_OUTPUT} ${CMAKE_CURRENT_BINARY_DIR}/${ofn}
-      PARENT_SCOPE)
+          PARENT_SCOPE)
 endfunction()
 
 # Import the pre-built mlir TableGen as an imported exetuable. It is required by
@@ -191,5 +201,5 @@ endfunction()
 # table gen utility itself can be detected and cause re-compilation of .td file.
 add_executable(mlir-tblgen IMPORTED)
 set_property(TARGET mlir-tblgen
-             PROPERTY IMPORTED_LOCATION ${LLVM_BUILD}/bin/mlir-tblgen)
+        PROPERTY IMPORTED_LOCATION ${LLVM_BUILD}/bin/mlir-tblgen)
 set(MLIR_TABLEGEN_EXE mlir-tblgen)

src/CMakeLists.txt

@@ -2,6 +2,7 @@ add_executable(onnf main.cpp)
 
 target_link_libraries(onnf builder compiler ${MLIRLibs} ${Boost_LIBRARIES})
 whole_archive_link_mlir(onnf ${MLIRWholeArchiveLibs})
+whole_archive_link_onnf(onnf onnf_transform)
 
 target_include_directories(onnf PRIVATE ${CMAKE_SOURCE_DIR})
 target_include_directories(onnf PRIVATE ${CMAKE_BINARY_DIR})

src/compiler/CMakeLists.txt

@@ -6,8 +6,8 @@ add_library(
         dialect/krnl/krnl_types.hpp
         dialect/onnx/onnx_ops.cpp
         dialect/onnx/onnx_ops.hpp
-        dialect/krnl/parser_helper.cpp
+        dialect/krnl/krnl_helper.cpp
-        dialect/krnl/parser_helper.hpp
+        dialect/krnl/krnl_helper.hpp
         pass/shape_inference_pass.cpp
         pass/shape_inference_interface.hpp
         dialect/onnx/onnxop.inc
@@ -82,4 +82,5 @@ target_include_directories(onnf_lower_frontend
 target_link_libraries(onnf_lower_frontend ${MLIRLibs})
 add_dependencies(onnf_lower_frontend gen_krnl_ops)
 
+add_subdirectory(transform)
 add_subdirectory(tool)

src/compiler/dialect/krnl/krnl_helper.cpp

@@ -0,0 +1,139 @@
+#include "mlir/Dialect/AffineOps/AffineOps.h"
+#include "mlir/IR/AffineExpr.h"
+
+#include "src/compiler/dialect/krnl/krnl_ops.hpp"
+
+#include "krnl_helper.hpp"
+
+namespace onnf {
+
+using namespace mlir;
+
+ParseResult KrnlDialectOperandParser::ParseOptionalOperand(
+    const Type& operandType, Value*& operand) {
+  // If operand queue is empty, parse more operands and cache them.
+  if (_operandRefQueue.empty()) {
+    // Parse operand types:
+    llvm::SmallVector<OpAsmParser::OperandType, 2> operand_refs;
+    _parser.parseOperandList(operand_refs);
+
+    // Record operands:
+    for (auto& operand_ref : operand_refs)
+      _operandRefQueue.emplace(operand_ref);
+  }
+
+  // If we parsed some operand reference(s), resolve the ref to an operand:
+  if (!_operandRefQueue.empty()) {
+    auto operand_ref = _operandRefQueue.front();
+    _operandRefQueue.pop();
+
+    llvm::SmallVector<Value*, 1> operands;
+    _parser.resolveOperand(operand_ref, operandType, operands);
+    operand = operands.front();
+    return success();
+  } else {
+    operand = nullptr;
+    return failure();
+  }
+}
+
+ParseResult KrnlDialectOperandParser::ParseOptionalOperand(
+    const Type& operandType, llvm::SmallVectorImpl<Value*>& operandList) {
+  Value* operand = nullptr;
+  if (ParseOptionalOperand(operandType, operand))
+    return failure();
+
+  operandList.emplace_back(operand);
+  return success();
+}
+
+ParseResult KrnlDialectOperandParser::ParseOperand(
+    const Type& operandType, Value*& operand) {
+  if (ParseOptionalOperand(operandType, operand))
+    return _parser.emitError(
+        _parser.getCurrentLocation(), "Expecting an operand.");
+  return success();
+}
+
+ParseResult KrnlDialectOperandParser::ParseOperand(
+    const Type& operandType, llvm::SmallVectorImpl<Value*>& operandList) {
+  if (ParseOptionalOperand(operandType, operandList))
+    return _parser.emitError(
+        _parser.getCurrentLocation(), "Expecting an operand.");
+
+  return success();
+}
+
+void printDimAndSymbolList(Operation::operand_iterator& begin, unsigned numDims,
+    unsigned numSymbols, OpAsmPrinter& p) {
+  p << '(';
+  p.printOperands(begin, begin + numDims);
+  p << ')';
+
+  if (numSymbols) {
+    p << '[';
+    p.printOperands(begin + numDims, begin + numDims + numSymbols);
+    p << ']';
+  }
+
+  begin = std::next(begin, numDims + numSymbols);
+}
+
+void printBound(AffineMapAttr boundMap,
+    Operation::operand_iterator& boundOperandsBeg, const char* prefix,
+    OpAsmPrinter& p) {
+  AffineMap map = boundMap.getValue();
+
+  // Check if this bound should be printed using custom assembly form.
+  // The decision to restrict printing custom assembly form to trivial cases
+  // comes from the will to roundtrip MLIR binary -> text -> binary in a
+  // lossless way.
+  // Therefore, custom assembly form parsing and printing is only supported for
+  // zero-operand constant maps and single symbol operand identity maps.
+  if (map.getNumResults() == 1) {
+    AffineExpr expr = map.getResult(0);
+
+    // Print constant bound.
+    if (map.getNumDims() == 0 && map.getNumSymbols() == 0) {
+      if (auto constExpr = expr.dyn_cast<AffineConstantExpr>()) {
+        p << constExpr.getValue();
+        return;
+      }
+    }
+
+    // Print bound that consists of a single SSA symbol if the map is over a
+    // single symbol.
+    if (map.getNumDims() == 0 && map.getNumSymbols() == 1) {
+      if (auto symExpr = expr.dyn_cast<AffineSymbolExpr>()) {
+        p.printOperand(*(boundOperandsBeg++));
+        return;
+      }
+    }
+  } else {
+    // Map has multiple results. Print 'min' or 'max' prefix.
+    p << prefix << ' ';
+  }
+
+  // Print the map and its operands.
+  p << boundMap;
+  printDimAndSymbolList(
+      boundOperandsBeg, map.getNumDims(), map.getNumSymbols(), p);
+}
+}  // namespace onnf
+
+namespace mlir {
+void KrnlIterateOperandPack::pushConstantBound(int64_t bound) {
+  if (boundMaps.size() % 2 == 0)
+    _operands.emplace_back(inputLoops[boundMaps.size() / 2]);
+  AffineMap map = builder.getConstantAffineMap(bound);
+  boundMaps.emplace_back(AffineMapAttr::get(map));
+}
+
+void KrnlIterateOperandPack::pushOperandBound(mlir::Value* operand) {
+  if (boundMaps.size() % 2 == 0)
+    _operands.emplace_back(inputLoops[boundMaps.size() / 2]);
+  AffineMap map = builder.getSymbolIdentityMap();
+  boundMaps.emplace_back(AffineMapAttr::get(map));
+  _operands.emplace_back(operand);
+}
+}  // namespace mlir

src/compiler/dialect/krnl/krnl_helper.hpp

@@ -0,0 +1,102 @@
+#pragma once
+
+#include <queue>
+
+#include "mlir/IR/Attributes.h"
+#include "mlir/IR/Builders.h"
+#include "mlir/IR/Dialect.h"
+#include "mlir/IR/OpDefinition.h"
+#include "mlir/IR/OpImplementation.h"
+#include "mlir/IR/StandardTypes.h"
+
+namespace onnf {
+
+class KrnlDialectOperandParser {
+ public:
+  explicit KrnlDialectOperandParser(mlir::OpAsmParser& parser)
+      : _parser(parser), _builder(parser.getBuilder()){};
+
+  // Parse an optional operand.
+  mlir::ParseResult ParseOptionalOperand(
+      const mlir::Type& operandType, mlir::Value*& operand);
+
+  // Parse an optional operand and push it to an operand list.
+  mlir::ParseResult ParseOptionalOperand(const mlir::Type& operandType,
+      llvm::SmallVectorImpl<mlir::Value*>& operandList);
+
+  // Parse a required operand.
+  mlir::ParseResult ParseOperand(
+      const mlir::Type& operandType, mlir::Value*& operand);
+
+  // Parse a required operand and push it to an operand list.
+  mlir::ParseResult ParseOperand(const mlir::Type& operandType,
+      llvm::SmallVectorImpl<mlir::Value*>& operandList);
+
+  // Do we have more operands to parse?
+  bool hasOperandLeft() { return !_operandRefQueue.empty(); }
+
+ private:
+  mlir::OpAsmParser& _parser;
+
+  mlir::Builder& _builder;
+
+  // A queue storing the parsed SSA id references.
+  std::queue<mlir::OpAsmParser::OperandType> _operandRefQueue;
+};
+
+// Adapted from:
+// https://github.com/tensorflow/mlir/blob/6a150d70c7e06fb37cddd7188fa48cde9a90fe59/lib/Dialect/StandardOps/Ops.cpp#L197
+// Main difference is that it advances the iterator `begin` as it consumes
+// dimension and symbol operands.
+void printDimAndSymbolList(mlir::Operation::operand_iterator& begin,
+    unsigned numDims, unsigned numSymbols, mlir::OpAsmPrinter& p);
+
+// Adapted from:
+// https://github.com/tensorflow/mlir/blob/5cb42c914fed14cebbbe5c170b4e2784d2628304/lib/Dialect/AffineOps/AffineOps.cpp#L1272
+// Main difference is that it advances the iterator `boundOperandsBeg` as it
+// prints bound.
+void printBound(mlir::AffineMapAttr boundMap,
+    mlir::Operation::operand_iterator& boundOperandsBeg, const char* prefix,
+    mlir::OpAsmPrinter& p);
+}  // namespace onnf
+
+namespace mlir {
+
+struct KrnlIterateOperandPack {
+  KrnlIterateOperandPack(mlir::Builder& builder,
+      llvm::ArrayRef<mlir::Value*> inputLoops,
+      llvm::ArrayRef<mlir::Value*> optimizedLoops)
+      : builder(builder),
+        inputLoops(inputLoops),
+        optimizedLoops(optimizedLoops) {
+    _operands.insert(
+        _operands.end(), optimizedLoops.begin(), optimizedLoops.end());
+  }
+
+  void pushConstantBound(int64_t bound);
+
+  void pushOperandBound(mlir::Value* operand);
+
+  llvm::SmallVector<mlir::Value*, 8> getOperands() const { return _operands; }
+
+  mlir::ArrayAttr getAttributes() const {
+    return builder.getArrayAttr(boundMaps);
+  }
+
+  size_t getNumOptimizedLoops() const { return optimizedLoops.size(); }
+
+  size_t getNumInputLoops() const { return inputLoops.size(); }
+
+ private:
+  int _boundIdx = 0;
+
+  llvm::SmallVector<mlir::Value*, 8> _operands;
+
+  llvm::SmallVector<mlir::Attribute, 8> boundMaps;
+
+  llvm::ArrayRef<mlir::Value*> inputLoops, optimizedLoops;
+
+  mlir::Builder& builder;
+};
+
+}  // namespace mlir

src/compiler/dialect/krnl/krnl_ops.cpp

@@ -9,10 +9,10 @@
 #include <iostream>
 #include <queue>
 
-#include "src/compiler/dialect/krnl/parser_helper.hpp"
-
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallBitVector.h"
+#include "mlir/Dialect/AffineOps/AffineOps.h"
+#include "mlir/Dialect/StandardOps/Ops.h"
 #include "mlir/IR/Block.h"
 #include "mlir/IR/Builders.h"
 #include "mlir/IR/Function.h"
@@ -24,6 +24,8 @@
 #include "mlir/IR/PatternMatch.h"
 #include "mlir/Transforms/DialectConversion.h"
 
+#include "src/compiler/dialect/krnl/krnl_helper.hpp"
+
 #include "krnl_ops.hpp"
 
 using namespace mlir;
@@ -52,26 +54,25 @@ void KrnlDefineLoopsOp::build(
 }
 
 void print(OpAsmPrinter& p, KrnlDefineLoopsOp& op) {
-  auto num_loop_attr = op.getAttrOfType<IntegerAttr>(op.getNumLoopsAttrName());
+  auto numLoopAttr =
-  p << "krnl.define_loops " << num_loop_attr.getValue().getSExtValue();
+      op.getAttrOfType<IntegerAttr>(KrnlDefineLoopsOp::getNumLoopsAttrName());
+  p << "krnl.define_loops " << numLoopAttr.getValue().getSExtValue();
 }
 
 ParseResult parseKrnlDefineLoopsOp(
     OpAsmParser& parser, OperationState& result) {
   // Parse the attribute indicating number of loops defined.
-  IntegerAttr num_loops;
+  IntegerAttr numLoops;
   auto& builder = parser.getBuilder();
-  auto int32_type = builder.getIntegerType(64);
+  auto intType = builder.getIntegerType(64);
-  if (parser.parseAttribute(num_loops, int32_type,
+  if (parser.parseAttribute(numLoops, intType,
           KrnlDefineLoopsOp::getNumLoopsAttrName(), result.attributes))
     return failure();
 
-  auto loop_types = llvm::SmallVector<Type, 4>(
+  auto loopTypes = llvm::SmallVector<Type, 4>(
-      num_loops.getValue().getSExtValue(), LoopType::get(builder.getContext()));
+      numLoops.getValue().getSExtValue(), LoopType::get(builder.getContext()));
-  if (parser.addTypesToList(loop_types, result.types))
+  if (parser.addTypesToList(loopTypes, result.types))
     return failure();
-
-  return success();
 }
 
 //===----------------------------------------------------------------------===//
@@ -142,39 +143,14 @@ ParseResult parseKrnlOptimizeLoopsOp(
  *   %i0 = 10 to N : %i1 = M to 20
  */
 void KrnlIterateOp::build(Builder* builder, OperationState& result,
-    ArrayRef<Value*> input_loops, ArrayRef<Value*> optimized_loops,
+    KrnlIterateOperandPack operandPack) {
-    ArrayRef<Value*> operand_bounds, ArrayRef<int64_t> const_bounds,
-    ArrayRef<int> bound_types) {
   // Record optimized loops and the number of such loops.
-  result.addOperands(optimized_loops);
+  result.addOperands(operandPack.getOperands());
+  result.addAttribute(
+      KrnlIterateOp::getBoundsAttrName(), operandPack.getAttributes());
+
   result.addAttribute(getNumOptimizedLoopsAttrName(),
-      builder->getI64IntegerAttr(optimized_loops.size()));
+      builder->getI64IntegerAttr(operandPack.getNumOptimizedLoops()));
-
-  // Record input loops and the number of such loops.
-  result.addOperands(input_loops);
-  result.addAttribute(getNumInputLoopsAttrName(),
-      builder->getI64IntegerAttr(input_loops.size()));
-
-  // Record bound either as attribute or from operand list.
-  auto next_operand_bound = operand_bounds.begin();
-  auto next_const_bound = const_bounds.begin();
-  for (size_t i = 0; i < bound_types.size(); i++) {
-    auto bound_type = bound_types[i];
-    if (bound_type == 0) {
-      // Constant bound.
-      result.addAttribute(getBoundAttrName(i / 2, i % 2),
-          builder->getI64IntegerAttr(*next_const_bound));
-      next_const_bound = std::next(next_const_bound);
-    } else {
-      // Operand bound.
-      result.addOperands(*next_operand_bound);
-      next_operand_bound = std::next(next_operand_bound);
-    }
-  }
-
-  // Record bound types as attribute:
-  result.addAttribute(KrnlIterateOp::getBoundTypesAttrName(),
-      builder->getI32ArrayAttr(bound_types));
 
   // Create a region and a block for the body. The arguments of the region are
   // the loop induction variables; there can be multiple induction variables
@@ -182,7 +158,7 @@ void KrnlIterateOp::build(Builder* builder, OperationState& result,
   Region* bodyRegion = result.addRegion();
   auto* body = new Block();
   auto body_args = llvm::SmallVector<Type, 4>(
-      input_loops.size(), IndexType::get(builder->getContext()));
+      operandPack.getNumInputLoops(), IndexType::get(builder->getContext()));
   body->addArguments(body_args);
   bodyRegion->push_back(body);
 
@@ -192,57 +168,31 @@ void KrnlIterateOp::build(Builder* builder, OperationState& result,
 void print(OpAsmPrinter& p, KrnlIterateOp& op) {
   p << "krnl.iterate(";
   // Print optimized loops:
-  auto num_optimized_loops = op.getNumOptimizedLoops();
+  auto numOptimizedLoops = op.getNumOptimizedLoops();
-  p.printOperands(op.operand_begin(), op.operand_begin() + num_optimized_loops);
+  p.printOperands(op.operand_begin(), op.operand_begin() + numOptimizedLoops);
   p << ") with (";
 
-  // Set up iterator to input loops:
+  auto inductionVars = op.bodyRegion().begin()->getArguments();
-  auto num_input_loops = op.getNumInputLoops();
+  auto boundItr =
-  auto input_loop_begin = op.operand_begin() + num_optimized_loops;
+      op.getAttrOfType<ArrayAttr>(KrnlIterateOp::getBoundsAttrName())
+          .getValue()
+          .begin();
+  auto operandItr = op.operand_begin() + numOptimizedLoops;
 
-  // Set up iterators to operand bounds.
+  std::string delimiter;
-  auto next_operand_bound = input_loop_begin + num_input_loops;
+  for (auto& var : inductionVars) {
-
+    p << delimiter;
-  // Function to print a lower or upper bound.
+    p.printOperand(*operandItr++);
-  auto print_bound = [&](ArrayRef<Attribute> bound_types, size_t idx) {
-    IntegerAttr type = bound_types[idx].dyn_cast<IntegerAttr>();
-    if (type.getValue().getSExtValue() == 0) {
-      // Bound is an integer attribute.
-      auto bound_idx = idx / 2;
-      auto is_ub = idx % 2;
-      IntegerAttr bound = op.getAttrOfType<IntegerAttr>(
-          KrnlIterateOp::getBoundAttrName(bound_idx, is_ub));
-      p << bound.getValue().getSExtValue();
-    } else {
-      // Bound is an operand.
-      p.printOperand(*next_operand_bound);
-      next_operand_bound = std::next(next_operand_bound);
-    }
-  };
-
-  auto induction_variables = op.bodyRegion().front().getArguments();
-  ArrayRef<Attribute> bound_types =
-      op.getAttrOfType<ArrayAttr>(KrnlIterateOp::getBoundTypesAttrName())
-          .getValue();
-
-  // Print input loop operands, induction variables and their ranges.
-  for (size_t i = 0; i < num_input_loops; i++) {
-    if (i != 0)
-      p << ", ";
-
-    p.printOperand(*std::next(input_loop_begin, i));
     p << " -> ";
-
+    p.printOperand(var);
-    // Print induction variable block argument.
-    p.printOperand(induction_variables[i]);
     p << " = ";
-
+    onnf::printBound((*boundItr++).cast<AffineMapAttr>(), operandItr, "max", p);
-    print_bound(bound_types, 2 * i);  // Print lower bound.
     p << " to ";
-    print_bound(bound_types, 2 * i + 1);  // Print upper bound.
+    onnf::printBound((*boundItr++).cast<AffineMapAttr>(), operandItr, "min", p);
+    delimiter = ", ";
   }
-  p << ")";
 
+  p << ")";
   p.printRegion(op.bodyRegion(), /*printEntryBlockArgs=*/false,
       /*printBlockTerminators=*/false);
 }
@@ -250,80 +200,109 @@ void print(OpAsmPrinter& p, KrnlIterateOp& op) {
 ParseResult parseKrnlIterateOp(OpAsmParser& parser, OperationState& result) {
   auto builder = parser.getBuilder();
   auto context = builder.getContext();
-  onnf::KrnlDialectOperandParser operand_parser(parser);
+  onnf::KrnlDialectOperandParser operandParser(parser);
 
   // Parse optimized loops:
-  SmallVector<OpAsmParser::OperandType, 4> num_optimized_loops;
+  SmallVector<OpAsmParser::OperandType, 4> optimizedLoopRefs;
   if (parser.parseOperandList(
-          num_optimized_loops, OpAsmParser::Delimiter::Paren) ||
+          optimizedLoopRefs, OpAsmParser::Delimiter::Paren) ||
-      parser.resolveOperands(num_optimized_loops,
+      parser.resolveOperands(optimizedLoopRefs,
           LoopType::get(result.getContext()), result.operands))
     return failure();
 
   // Record how many optimized loops did we parse.
   result.addAttribute(KrnlIterateOp::getNumOptimizedLoopsAttrName(),
-      builder.getI64IntegerAttr(num_optimized_loops.size()));
+      builder.getI64IntegerAttr(optimizedLoopRefs.size()));
 
   // Parse input loops and their lower and upper bounds.
-  SmallVector<OpAsmParser::OperandType, 4> in_loop_refs, induction_var_refs;
+  SmallVector<OpAsmParser::OperandType, 4> inductionVarRefs;
-  SmallVector<Value*, 4> in_loop_operands, operand_bounds;
+  SmallVector<Attribute, 4> boundMaps;
-  SmallVector<Attribute, 4> bound_types;
-  SmallVector<IntegerAttr, 4> const_bounds;
 
   if (parser.parseKeyword("with") || parser.parseLParen())
     return failure();
 
   // A function to parse a lower or upper bound.
-  auto parse_bound = [&result, &builder, &operand_parser, &parser, &bound_types,
+  auto parseBound = [&result, &builder, &parser, &operandParser, &boundMaps](
-                         &operand_bounds, &const_bounds](
+                        bool isUpper) -> ParseResult {
-                         bool is_ub, size_t bound_pair_count) -> ParseResult {
+    // 'min' / 'max' prefixes are generally syntactic sugar, but are required if
+    // the map has multiple results.
+    bool failedToParsedMinMax =
+        failed(parser.parseOptionalKeyword(isUpper ? "min" : "max"));
+
     // Try parse an SSA operand.
-    Value* bound;
+    if (succeeded(operandParser.ParseOptionalOperand(
-    operand_parser.ParseOptionalOperand(builder.getIndexType(), bound);
+            builder.getIndexType(), result.operands))) {
+      AffineMap map = builder.getSymbolIdentityMap();
+      boundMaps.emplace_back(AffineMapAttr::get(map));
+      return success();
+    }
 
-    if (bound != nullptr) {
+    // Bound is not an SSA id, then it must be an integer.
-      // Parsed an SSA id as bound.
+    // Parse an integer constant attribute.
-      operand_bounds.emplace_back(bound);
+    // Get the attribute location.
-      // Record bound_type as an operand type.
+    llvm::SMLoc attrLoc = parser.getCurrentLocation();
-      bound_types.emplace_back(builder.getI32IntegerAttr(0));
+    Attribute boundAttr;
-    } else {
+    llvm::SmallVector<NamedAttribute, 1> tempBoundAttrContainer;
-      // Bound is not an SSA id, then it must be an integer.
+    if (parser.parseAttribute(
-      // Parse an integer constant attribute.
+            boundAttr, builder.getIndexType(), "temp", tempBoundAttrContainer))
-      IntegerAttr boundAttr;
+      return failure();
-      if (parser.parseAttribute(boundAttr, builder.getIndexType(),
+
-              KrnlIterateOp::getBoundAttrName(bound_pair_count, is_ub),
+    if (auto affineMapAttr = boundAttr.dyn_cast<AffineMapAttr>()) {
-              result.attributes))
+      unsigned currentNumOperands = result.operands.size();
+      unsigned numDims = 0;
+      if (parseDimAndSymbolList(parser, result.operands, numDims))
         return failure();
-      const_bounds.emplace_back(
-          builder.getIntegerAttr(builder.getIndexType(), boundAttr.getValue()));
 
-      // Record that the bound_type is a constant integer attribute.
+      auto map = affineMapAttr.getValue();
-      bound_types.emplace_back(builder.getI32IntegerAttr(1));
+      if (map.getNumDims() != numDims)
+        return parser.emitError(parser.getNameLoc(),
+            "dim operand count and integer set dim count must match");
+
+      unsigned numDimAndSymbolOperands =
+          result.operands.size() - currentNumOperands;
+      if (numDims + map.getNumSymbols() != numDimAndSymbolOperands)
+        return parser.emitError(parser.getNameLoc(),
+            "symbol operand count and integer set symbol count must match");
+
+      // If the map has multiple results, make sure that we parsed the min/max
+      // prefix.
+      if (map.getNumResults() > 1 && failedToParsedMinMax) {
+        if (isUpper)
+          return parser.emitError(attrLoc,
+              "upper loop bound affine map with multiple "
+              "results requires 'min' prefix");
+        return parser.emitError(attrLoc,
+            "lower loop bound affine mapwith "
+            "multiple results requires 'max' prefix");
+      }
+      boundMaps.emplace_back(AffineMapAttr::get(map));
+      return success();
+    }
+
+    if (auto integerAttr = boundAttr.dyn_cast<IntegerAttr>()) {
+      AffineMap map =
+          builder.getConstantAffineMap(integerAttr.getValue().getSExtValue());
+      boundMaps.emplace_back(AffineMapAttr::get(map));
     }
   };
 
-  bool keep_parsing;            // Do we keep parsing loops/bounds?
+  bool keepParsing;  // Do we keep parsing loops/bounds?
-  size_t bound_pair_count = 0;  // Record the number of bound pairs parsed.
   do {
     // Parse an input loop operand;
-    Value* in_loop_operand;
+    operandParser.ParseOperand(LoopType::get(context), result.operands);
-    operand_parser.ParseOperand(LoopType::get(context), in_loop_operand);
-    in_loop_operands.emplace_back(in_loop_operand);
-
     parser.parseArrow();
 
     // Parse induction variable.
-    OpAsmParser::OperandType induction_var;
+    OpAsmParser::OperandType inductionVar;
-    if (parser.parseRegionArgument(induction_var) || parser.parseEqual())
+    if (parser.parseRegionArgument(inductionVar) || parser.parseEqual())
       return failure();
-    induction_var_refs.emplace_back(induction_var);
+    inductionVarRefs.emplace_back(inductionVar);
 
     // Parse bound par (min to max).
-    if (parse_bound(false, bound_pair_count) || parser.parseKeyword("to") ||
+    if (parseBound(/*isUpper=*/false) || parser.parseKeyword("to") ||
-        parse_bound(true, bound_pair_count))
+        parseBound(/*isUpper=*/true))
       return failure();
 
-    bound_pair_count++;
     // We may fail to parse a comma if an operand bound is followed by
     // a comma and the next input loop operand, in which case
     // the entire "{operand bound}, {input_loop_operand}" sequence will
@@ -331,33 +310,19 @@ ParseResult parseKrnlIterateOp(OpAsmParser& parser, OperationState& result) {
     parser.parseOptionalComma();
 
     // If we don't see a RParen token, we keep parsing.
-    keep_parsing = failed(parser.parseOptionalRParen());
+    keepParsing = failed(parser.parseOptionalRParen());
-  } while (keep_parsing);
+  } while (keepParsing);
 
   // At this point, there shouldn't be any operands left to parse.
-  if (operand_parser.has_operand_left())
+  if (operandParser.hasOperandLeft())
     return parser.emitError(parser.getCurrentLocation());
+  result.addAttribute(
+      KrnlIterateOp::getBoundsAttrName(), builder.getArrayAttr(boundMaps));
 
-  // Record how many input loops did we parse.
-  result.addOperands(in_loop_operands);
-  result.addAttribute(KrnlIterateOp::getNumInputLoopsAttrName(),
-      builder.getI64IntegerAttr(in_loop_operands.size()));
-
-  // Add operand bounds to the list of operands of current operation.
-  result.addOperands(operand_bounds);
-
-  // A list of 2N elements where the (2n) and (2n+1) th element specifies
-  // whether the lower and upper bound of the n'th induction variable is stored
-  // as an operand or as an attribute. N being the number of input loops
-  // specified in this krnl.iterate operation.
-  result.addAttribute(KrnlIterateOp::getBoundTypesAttrName(),
-      builder.getArrayAttr(bound_types));
-
-  // Parse the schedule body region.
   Region* region = result.addRegion();
-  SmallVector<Type, 4> induction_var_types(
+  SmallVector<Type, 4> inductionVarTypes(
-      induction_var_refs.size(), builder.getIndexType());
+      inductionVarRefs.size(), builder.getIndexType());
-  if (parser.parseRegion(*region, induction_var_refs, induction_var_types))
+  if (parser.parseRegion(*region, inductionVarRefs, inductionVarTypes))
     return failure();
 
   // Ensure iterate region is closed off with krnl.terminate.

src/compiler/dialect/krnl/krnl_ops.hpp

@@ -14,6 +14,7 @@
 #include "mlir/IR/OpDefinition.h"
 #include "mlir/IR/StandardTypes.h"
 
+#include "src/compiler/dialect/krnl/krnl_helper.hpp"
 #include "src/compiler/dialect/krnl/krnl_types.hpp"
 
 namespace mlir {

src/compiler/dialect/krnl/krnl_ops.td

@@ -8,6 +8,7 @@
 
 include "mlir/IR/OpBase.td"
 
+
 def Krnl_Dialect : Dialect {
   let name = "krnl";
   let cppNamespace = "";
@@ -119,17 +120,14 @@ def KrnlIterateOp : Op<Krnl_Dialect, "iterate", [ImplicitKrnlTerminator]> {
 
   let builders = [
     OpBuilder<"Builder *builder, OperationState &result, "
-              "ArrayRef<Value*> input_loops, ArrayRef<Value*> optimized_loops, "
+              "KrnlIterateOperandPack operandPack">
-              "ArrayRef<Value*> operand_bounds, ArrayRef<int64_t> const_bounds, "
-              "ArrayRef<int> bound_types">
   ];
 
   let extraClassDeclaration = [{
-
+    // In krnl.iterate operation, operands are stored as such
-    // In krnl.iterate operation, three types of SSA values are stored:
     // - Optimized krnl.loops.
-    // - Input krnl.loops.
+    // - Input krnl.loops and their operand bounds. (TODO(Tian) explain better how we store them).
-    // - SSA value based induction variable bound (parametric bound).
+
     // We record the number of optimized and input loops to separate these three
     // group of operands out.
     static StringRef getNumOptimizedLoopsAttrName() { return "num_optimized_loops"; }
@@ -143,32 +141,8 @@ def KrnlIterateOp : Op<Krnl_Dialect, "iterate", [ImplicitKrnlTerminator]> {
       return num_optimized_loops;
     }
 
-    static StringRef getNumInputLoopsAttrName() { return "num_input_loops"; }
+    // Get name of the attribute for storing bound represented using affine maps.
-
+    static StringRef getBoundsAttrName() { return "bounds"; }
-    int64_t getNumInputLoops() {
-      auto num_loops =
-        getAttrOfType<IntegerAttr>(
-                getNumInputLoopsAttrName())
-              .getValue()
-              .getSExtValue();
-      return num_loops;
-    }
-
-    // Constant bounds are stored here as a list attribute.
-    static StringRef getConstantBoundsAttrName() { return "constant_bounds"; }
-
-    // Store type of each bound as three types:
-    // - 0 = constant attribute.
-    // - 1 = operand type.
-    // - 2 = affine maps (TODO).
-    static StringRef getBoundTypesAttrName() { return "bound_types"; }
-
-    // Get dynamic attribute name for the i-th lower and upper bound.
-    static std::string getBoundAttrName(int64_t i, bool is_ub) {
-      std::string bound_type = is_ub ? "_ub" : "_lb";
-      std::string bound_idx = std::to_string(i);
-      return "__bound_" + bound_idx + bound_type;
-    }
     }];
 
   let printer = [{ return ::print(p, *this); }];

src/compiler/dialect/krnl/parser_helper.cpp

@@ -1,52 +0,0 @@
-//===------------------ parser_helper.cpp - MLIR Operations ---------------===//
-//
-// Copyright 2019 The IBM Research Authors.
-//
-// =============================================================================
-//
-//===----------------------------------------------------------------------===//
-
-#include "parser_helper.hpp"
-
-#include "src/compiler/dialect/krnl/krnl_ops.hpp"
-
-namespace onnf {
-
-mlir::ParseResult KrnlDialectOperandParser::ParseOptionalOperand(
-    mlir::Type operand_type, mlir::Value*& operand) {
-  // If operand queue is empty, parse more operands and cache them.
-  if (_operand_ref_queue.empty()) {
-    // Parse operand types:
-    llvm::SmallVector<mlir::OpAsmParser::OperandType, 2> operand_refs;
-    _parser.parseOperandList(operand_refs);
-
-    // Record operands:
-    for (auto& operand_ref : operand_refs)
-      _operand_ref_queue.emplace(operand_ref);
-  }
-
-  // If we parsed some operand reference(s), resolve the ref to an operand:
-  if (!_operand_ref_queue.empty()) {
-    auto operand_ref = _operand_ref_queue.front();
-    _operand_ref_queue.pop();
-
-    llvm::SmallVector<mlir::Value*, 1> operands;
-    _parser.resolveOperand(operand_ref, operand_type, operands);
-    operand = operands.front();
-    return mlir::success();
-  } else {
-    operand = nullptr;
-    return mlir::failure();
-  }
-}
-
-mlir::ParseResult KrnlDialectOperandParser::ParseOperand(
-    mlir::Type operand_type, mlir::Value*& operand) {
-  ParseOptionalOperand(operand_type, operand);
-  if (operand == nullptr)
-    return _parser.emitError(
-        _parser.getCurrentLocation(), "Expecting an operand.");
-  return mlir::success();
-}
-
-}  // namespace onnf

src/compiler/dialect/krnl/parser_helper.hpp

@@ -1,46 +0,0 @@
-//===------------------ parser_helper.hpp - MLIR Operations ---------------===//
-//
-// Copyright 2019 The IBM Research Authors.
-//
-// =============================================================================
-//
-//===----------------------------------------------------------------------===//
-
-#pragma once
-
-#include <queue>
-
-#include "mlir/IR/Builders.h"
-#include "mlir/IR/Dialect.h"
-#include "mlir/IR/OpDefinition.h"
-#include "mlir/IR/OpImplementation.h"
-#include "mlir/IR/StandardTypes.h"
-
-namespace onnf {
-
-class KrnlDialectOperandParser {
- public:
-  KrnlDialectOperandParser(mlir::OpAsmParser& parser)
-      : _parser(parser), _builder(parser.getBuilder()){};
-
-  // Parse an optional operand.
-  mlir::ParseResult ParseOptionalOperand(
-      mlir::Type operand_type, mlir::Value*& operand);
-
-  // Parse a required operand.
-  mlir::ParseResult ParseOperand(
-      mlir::Type operand_type, mlir::Value*& operand);
-
-  // Do we have more operands to parse?
-  bool has_operand_left() { return !_operand_ref_queue.empty(); }
-
- private:
-  mlir::OpAsmParser& _parser;
-
-  mlir::Builder& _builder;
-
-  // A queue storing the parsed SSA id references.
-  std::queue<mlir::OpAsmParser::OperandType> _operand_ref_queue;
-};
-
-}  // namespace onnf

src/compiler/pass/lower_frontend_to_krnl.cpp

@@ -16,6 +16,7 @@
 #include "mlir/Pass/Pass.h"
 #include "mlir/Transforms/DialectConversion.h"
 
+#include "src/compiler/dialect/krnl/krnl_helper.hpp"
 #include "src/compiler/dialect/krnl/krnl_ops.hpp"
 #include "src/compiler/dialect/onnx/onnx_ops.hpp"
 
@@ -43,13 +44,12 @@ static MemRefType convertTensorToMemRef(TensorType type) {
 }
 
 /// Insert an allocation and deallocation for the given MemRefType.
-static Value* insertAllocAndDealloc(
+static Value* insertAllocAndDealloc(MemRefType type, Location loc,
-    MemRefType type, Location loc, PatternRewriter& rewriter,
+    PatternRewriter& rewriter, Value* oldMemRef = nullptr) {
-    Value *oldMemRef = nullptr) {
   // Put together alloc operands for any dynamic dimensions of the memref.
   AllocOp alloc;
   if (oldMemRef) {
-    SmallVector<Value *, 4> allocOperands;
+    SmallVector<Value*, 4> allocOperands;
     auto memRefShape = type.getShape();
     for (int i = 0; i < memRefShape.size(); ++i)
       if (memRefShape[i] < 0)
@@ -95,7 +95,7 @@ struct ONNXAddOpLowering : public ConversionPattern {
     // dimensions with the result at this pre-optimization phase.
     // TODO: verify that dimensions match.
     // TODO: can the dimension of the result differ after optimizations?
-    Value *alloc;
+    Value* alloc;
     if (hasAllConstantDimensions(memRefType))
       alloc = insertAllocAndDealloc(memRefType, loc, rewriter);
     else
@@ -122,33 +122,22 @@ struct ONNXAddOpLowering : public ConversionPattern {
     }
     Block& optimizationBlock = optimizedLoopsOp.region().front();
 
+    KrnlIterateOperandPack pack(rewriter, originalLoops, optimizedLoops);
     // Iterate over the loop nest.
     // TODO (Tian): move this logic inside KrnlIterateOp. Pass MemRefShape
     // to KrnlIterateOp instead.
-    SmallVector<Value*, 8> operandBounds;
-    SmallVector<int64_t, 8> constBounds;
-    SmallVector<int, 16> boundTypes;
     for (int i = 0; i < rank; ++i) {
       if (memRefShape[i] < 0) {
-        // This is a dynamic value, hence use operands.
+        pack.pushConstantBound(0);
-        // Lower bound
+        pack.pushOperandBound(
-        constBounds.push_back(0);
-        boundTypes.push_back(0);
-        // Upper bound
-        operandBounds.push_back(
             rewriter.create<DimOp>(loc, operands[0], i).getResult());
-        boundTypes.push_back(1);
       } else {
-        // Lower bound
+        pack.pushConstantBound(0);
-        constBounds.push_back(0);
+        pack.pushConstantBound(memRefShape[i]);
-        boundTypes.push_back(0);
-        // Upper bound
-        constBounds.push_back(memRefShape[i]);
-        boundTypes.push_back(0);
       }
     }
-    auto iterateOp = rewriter.create<KrnlIterateOp>(loc, originalLoops,
+
-        optimizedLoops, operandBounds, constBounds, boundTypes);
+    auto iterateOp = rewriter.create<KrnlIterateOp>(loc, pack);
     Block& iterationBlock = iterateOp.bodyRegion().front();
 
     // Now perform the insertions into the body of the
@@ -169,14 +158,12 @@ struct ONNXAddOpLowering : public ConversionPattern {
     SmallVector<Value*, 4> loopIVs;
     for (auto arg : iterationBlock.getArguments())
       loopIVs.push_back(arg);
-    auto loadedFirstVal =
+    auto loadedFirstVal = rewriter.create<LoadOp>(loc, operands[0], loopIVs);
-        rewriter.create<LoadOp>(loc, operands[0], loopIVs);
+    auto loadedSecondVal = rewriter.create<LoadOp>(loc, operands[1], loopIVs);
-    auto loadedSecondVal =
-        rewriter.create<LoadOp>(loc, operands[1], loopIVs);
 
     // TODO: Choose type of the Add for now use the Float Add.
-    auto addOpResult = rewriter.create<AddFOp>(
+    auto addOpResult =
-        loc, loadedFirstVal, loadedSecondVal);
+        rewriter.create<AddFOp>(loc, loadedFirstVal, loadedSecondVal);
 
     // Store result in the resulting array.
     rewriter.create<StoreOp>(loc, addOpResult, alloc, loopIVs);
@@ -209,8 +196,8 @@ struct TensorTypeConverter : public TypeConverter {
   /// inputs. Once unranked results can be handled gracefully this
   /// override needs to be removed in favour of the original MLIR one.]
   bool isSignatureLegal(FunctionType funcType) {
-    return llvm::all_of(funcType.getInputs(),
+    return llvm::all_of(
-        [this](Type type) { return isLegal(type); });
+        funcType.getInputs(), [this](Type type) { return isLegal(type); });
   }
 };
 
@@ -272,8 +259,7 @@ void FrontendToKrnlLoweringPass::runOnModule() {
   // With the target and rewrite patterns defined, we can now attempt the
   // conversion. The conversion will signal failure if any of our `illegal`
   // operations were not converted successfully.
-  if (failed(applyPartialConversion(
+  if (failed(applyPartialConversion(module, target, patterns)))
-          module, target, patterns)))
     signalPassFailure();
 }
 

src/compiler/pass/passes.hpp

@@ -17,9 +17,10 @@ class Pass;
 
 std::unique_ptr<Pass> createShapeInferencePass();
 
-/// Pass for lowering frontend dialects to Krnl IR dialect.
+/// Add pass for lowering to Krnl IR.
-std::unique_ptr<mlir::Pass> createLowerToKrnlPass();
+std::unique_ptr<Pass> createLowerToKrnlPass();
 
-// TODO: Add pass for lowering to LLVM IR.
+/// Pass for lowering frontend dialects to Krnl IR dialect.
+std::unique_ptr<Pass> createLowerKrnlPass();
 
 }  // end namespace mlir

src/compiler/pass/shape_inference_pass.cpp

@@ -75,7 +75,7 @@ class ShapeInferencePass : public mlir::FunctionPass<ShapeInferencePass> {
     if (auto terminator_op = f.getBody().back().getTerminator()) {
       auto results = terminator_op->getOperandTypes();
       f.setType(FunctionType::get(f.getType().getInputs(),
-                std::vector<Type>(results.begin(), results.end()), f.getContext()));
+          std::vector<Type>(results.begin(), results.end()), f.getContext()));
     }
   }
 

src/compiler/tool/onnf_opt/CMakeLists.txt

@@ -6,8 +6,7 @@ target_include_directories(onnf-opt PRIVATE ${ONNF_BIN_ROOT})
 
 target_link_libraries(onnf-opt compiler ${MLIRLibs})
 whole_archive_link_mlir(onnf-opt ${MLIRWholeArchiveLibs})
-whole_archive_link_onnf(onnf-opt onnf_lower_frontend)
+whole_archive_link_onnf(onnf-opt onnf_transform onnf_lower_frontend onnf_shape_inference)
-whole_archive_link_onnf(onnf-opt onnf_shape_inference)
 
 # TODO: need to investigate how to whole-archive link compiler pass to onnf-opt.
 target_link_libraries(onnf-opt compiler)

src/compiler/transform/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_library(onnf_transform lower_krnl.cpp)
+
+target_include_directories(onnf_transform
+                           PRIVATE ${ONNF_SRC_ROOT} ${ONNF_BIN_ROOT}
+                                   ${ONNF_SRC_ROOT})
+target_link_libraries(onnf_transform ${MLIRLibs})
+add_dependencies(onnf_transform gen_krnl_ops)

src/compiler/transform/lower_krnl.cpp

@@ -0,0 +1,161 @@
+#include "mlir/Dialect/AffineOps/AffineOps.h"
+#include "mlir/Dialect/StandardOps/Ops.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/DialectConversion.h"
+
+#include "src/compiler/dialect/krnl/krnl_ops.hpp"
+#include "src/compiler/pass/passes.hpp"
+
+using namespace mlir;
+
+namespace {
+
+//===----------------------------------------------------------------------===//
+// Krnl to Affine Rewrite Patterns: KrnlIterate operation.
+//===----------------------------------------------------------------------===//
+
+struct KrnlIterateOpLowering : public OpRewritePattern<KrnlIterateOp> {
+  using OpRewritePattern<KrnlIterateOp>::OpRewritePattern;
+
+  PatternMatchResult matchAndRewrite(
+      KrnlIterateOp iterateOp, PatternRewriter& rewriter) const override {
+    auto boundMapAttrs =
+        iterateOp.getAttrOfType<ArrayAttr>(KrnlIterateOp::getBoundsAttrName())
+            .getValue();
+    auto operandItr =
+        iterateOp.operand_begin() + iterateOp.getNumOptimizedLoops();
+    SmallVector<AffineForOp, 4> nestedForOps;
+    for (size_t boundIdx = 0; boundIdx < boundMapAttrs.size(); boundIdx += 2) {
+      // Consume input loop operand, currently do not do anything with it.
+      operandItr++;
+
+      // Organize operands into lower/upper bounds in affine.for ready formats.
+      SmallVector<Value*, 4> lbOperands, ubOperands;
+      AffineMap lbMap, ubMap;
+      for (int boundType = 0; boundType < 2; boundType++) {
+        auto& operands = boundType == 0 ? lbOperands : ubOperands;
+        auto& map = boundType == 0 ? lbMap : ubMap;
+        map = boundMapAttrs[boundIdx + boundType]
+                  .cast<AffineMapAttr>()
+                  .getValue();
+        operands.insert(
+            operands.end(), operandItr, operandItr + map.getNumInputs());
+        std::advance(operandItr, map.getNumInputs());
+      }
+
+      nestedForOps.emplace_back(rewriter.create<AffineForOp>(
+          iterateOp.getLoc(), lbOperands, lbMap, ubOperands, ubMap));
+      rewriter.setInsertionPoint(nestedForOps.back().getBody(),
+          nestedForOps.back().getBody()->begin());
+    }
+
+    // Replace induction variable references from those introduced by a
+    // single krnl.iterate to those introduced by multiple affine.for
+    // operations.
+    for (size_t i = 0; i < nestedForOps.size() - 1; i++) {
+      auto iterateIV = iterateOp.bodyRegion().front().getArgument(0);
+      auto forIV = nestedForOps[i].getBody()->getArgument(0);
+      iterateIV->replaceAllUsesWith(forIV);
+      iterateOp.bodyRegion().front().eraseArgument(0);
+    }
+
+    // Pop krnl.iterate body region block arguments, leave the last one
+    // for convenience (it'll be taken care of by region inlining).
+    while (iterateOp.bodyRegion().front().getNumArguments() > 1)
+      iterateOp.bodyRegion().front().eraseArgument(0);
+
+    // Transfer krnl.iterate region to innermost for op.
+    auto innermostForOp = nestedForOps.back();
+    innermostForOp.region().getBlocks().clear();
+    rewriter.inlineRegionBefore(iterateOp.bodyRegion(), innermostForOp.region(),
+        innermostForOp.region().end());
+
+    rewriter.eraseOp(iterateOp);
+    return matchSuccess();
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// Krnl to Affine Rewrite Patterns: KrnlTerminator operation.
+//===----------------------------------------------------------------------===//
+
+class KrnlTerminatorLowering : public OpRewritePattern<KrnlTerminatorOp> {
+ public:
+  using OpRewritePattern<KrnlTerminatorOp>::OpRewritePattern;
+
+  PatternMatchResult matchAndRewrite(
+      KrnlTerminatorOp op, PatternRewriter& rewriter) const override {
+    rewriter.replaceOpWithNewOp<AffineTerminatorOp>(op);
+    return matchSuccess();
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// Krnl to Affine Rewrite Patterns: KrnlDefineLoops operation.
+//===----------------------------------------------------------------------===//
+
+class KrnlDefineLoopsLowering : public OpRewritePattern<KrnlDefineLoopsOp> {
+ public:
+  using OpRewritePattern<KrnlDefineLoopsOp>::OpRewritePattern;
+
+  PatternMatchResult matchAndRewrite(
+      KrnlDefineLoopsOp op, PatternRewriter& rewriter) const override {
+    rewriter.eraseOp(op);
+    return matchSuccess();
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// Krnl to Affine Rewrite Patterns: KrnlOptimizeLoops operation.
+//===----------------------------------------------------------------------===//
+
+class KrnlOptimizeLoopsLowering : public OpRewritePattern<KrnlOptimizeLoopsOp> {
+ public:
+  using OpRewritePattern<KrnlOptimizeLoopsOp>::OpRewritePattern;
+
+  PatternMatchResult matchAndRewrite(
+      KrnlOptimizeLoopsOp op, PatternRewriter& rewriter) const override {
+    rewriter.eraseOp(op);
+    return matchSuccess();
+  }
+};
+
+//===----------------------------------------------------------------------===//
+// KrnlToAffineLoweringPass
+//===----------------------------------------------------------------------===//
+
+/// This is a partial lowering to affine loops of the krnl dialect operations.
+/// At this stage the dialect will contain standard operations as well like
+/// add and multiply, this pass will leave these operations intact.
+namespace {
+struct KrnlToAffineLoweringPass
+    : public FunctionPass<KrnlToAffineLoweringPass> {
+  void runOnFunction() final;
+};
+}  // end anonymous namespace.
+
+void KrnlToAffineLoweringPass::runOnFunction() {
+  auto function = getFunction();
+
+  ConversionTarget target(getContext());
+
+  target.addLegalDialect<AffineOpsDialect, StandardOpsDialect>();
+  // We expect IR to be free of Krnl Dialect Ops.
+  target.addIllegalDialect<KrnlOpsDialect>();
+
+  OwningRewritePatternList patterns;
+  patterns.insert<KrnlIterateOpLowering, KrnlTerminatorLowering,
+      KrnlDefineLoopsLowering, KrnlOptimizeLoopsLowering>(&getContext());
+
+  if (failed(applyPartialConversion(getFunction(), target, patterns)))
+    signalPassFailure();
+}
+
+}  // namespace
+
+std::unique_ptr<Pass> mlir::createLowerKrnlPass() {
+  return std::make_unique<KrnlToAffineLoweringPass>();
+}
+
+static PassRegistration<KrnlToAffineLoweringPass> pass(
+    "lower-krnl", "Lower Krnl dialect.");

src/main.cpp

@@ -28,6 +28,7 @@
 
 #include <boost/program_options.hpp>
 
+#include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/Support/FileUtilities.h"
 #include "llvm/Support/Regex.h"
 #include "llvm/Support/SourceMgr.h"
@@ -38,6 +39,8 @@
 #include "src/compiler/pass/passes.hpp"
 
 #include "mlir/Analysis/Verifier.h"
+#include "mlir/Conversion/LoopToStandard/ConvertLoopToStandard.h"
+#include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVMPass.h"
 #include "mlir/ExecutionEngine/ExecutionEngine.h"
 #include "mlir/ExecutionEngine/OptUtils.h"
 #include "mlir/IR/MLIRContext.h"
@@ -125,7 +128,20 @@ int main(int ac, char* av[]) {
   pm.addPass(mlir::createShapeInferencePass());
   pm.addPass(mlir::createCanonicalizerPass());
   pm.addPass(mlir::createLowerToKrnlPass());
+  pm.addPass(mlir::createLowerKrnlPass());
+  pm.addPass(mlir::createLowerAffinePass());
+  pm.addPass(mlir::createLowerToCFGPass());
+  pm.addPass(mlir::createLowerToLLVMPass());
+  pm.addPass(mlir::createCanonicalizerPass());
   pm.run(*module);
 
+  // Write LLVM bitcode to disk.
+  std::error_code EC;
+  llvm::raw_fd_ostream moduleBitcodeStream(
+      "model.bc", EC, llvm::sys::fs::F_None);
+  llvm::WriteBitcodeToFile(
+      *mlir::translateModuleToLLVMIR(*module), moduleBitcodeStream);
+  moduleBitcodeStream.flush();
+
   return 0;
 }

test/mlir/krnl/ops.mlir

@@ -0,0 +1,75 @@
+// RUN: onnf-opt %s -mlir-print-op-generic | FileCheck -check-prefix=GENERIC %s
+// RUN: onnf-opt %s | FileCheck %s
+
+// GENERIC-DAG: #{{.*}} = () -> (0)
+// GENERIC-DAG: #{{.*}} = () -> (10)
+// GENERIC-DAG: #{{.*}} = () -> (1)
+// GENERIC-DAG: #{{.*}} = () -> (11)
+// GENERIC-DAG: #{{.*}} = (d0, d1) -> (d0 - d1)
+// GENERIC-DAG: #{{.*}} = (d0, d1) -> (d0 + d1)
+
+func @simple_iterate(%N : index) {
+  %ii, %ij, %ik = krnl.define_loops 3
+  %oi, %oj, %ok = krnl.optimize_loops  {
+    krnl.return_loops %ii, %ij, %ik
+  } : () -> (!krnl.loop, !krnl.loop, !krnl.loop)
+
+  // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+  // GENERIC-NEXT: ^bb0(%{{.*}}: index, %{{.*}}: index):
+  // GENERIC-NEXT: "krnl.terminate"() : () -> ()
+  // GENERIC-NEXT: bounds = [#{{.*}}, #{{.*}}, #{{.*}}, #{{.*}}]
+
+  // CHECK: krnl.iterate(%{{.*}}, %{{.*}}) with (%{{.*}} -> %{{.*}} = 0 to 10, %{{.*}} -> %{{.*}} = 1 to 11) {
+  krnl.iterate(%oi, %oj) with (%ii -> %i = 0 to 10, %ij -> %j = 1 to 11) {
+
+  }
+
+  // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+  // GENERIC-NEXT: ^bb0(%{{.*}}: index, %{{.*}}: index):
+  // CHECK: krnl.iterate(%{{.*}}, %{{.*}}) with (%{{.*}} -> %{{.*}} = 0 to 10, %{{.*}} -> %{{.*}} = 0 to 10) {
+  krnl.iterate(%oi, %oj) with (%ii -> %i = 0 to 10, %ij -> %j = 0 to 10) {
+    // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}) ( {
+    // GENERIC-NEXT: ^bb0(%{{.*}}: index):
+    // CHECK: krnl.iterate(%{{.*}}) with (%{{.*}} -> %{{.*}} = 0 to 10) {
+    krnl.iterate(%ok) with (%ik -> %k = 0 to 10) {
+
+    }
+  }
+
+  // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+  // GENERIC-NEXT: ^bb0(%{{.*}}: index, %{{.*}}: index):
+  // CHECK: krnl.iterate(%{{.*}}, %{{.*}}) with (%{{.*}} -> %{{.*}} = 0 to %{{.*}}, %{{.*}} -> %{{.*}} = 0 to 10) {
+  krnl.iterate(%oi, %oj) with (%ii -> %i = 0 to %N, %ij -> %j = 0 to 10) {
+
+  }
+
+  return
+}
+
+func @affine_map_bound(%N : index) {
+  %ii, %ij, %ik = krnl.define_loops 3
+  %oi, %oj, %ok = krnl.optimize_loops  {
+    krnl.return_loops %ii, %ij, %ik
+  } : () -> (!krnl.loop, !krnl.loop, !krnl.loop)
+
+  // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+  // GENERIC-NEXT: ^bb0(%{{.*}}: index, %{{.*}}: index):
+  // CHECK: krnl.iterate(%{{.*}}, %{{.*}}) with (%{{.*}} -> %{{.*}} = 0 to 10, %{{.*}} -> %{{.*}} = 0 to 10) {
+  krnl.iterate(%oi, %oj) with (%ii -> %i = ()->(0)() to ()->(10)(), %ij -> %j = 0 to 10) {
+    // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+    // GENERIC-NEXT: ^bb0(%{{.*}}: index):
+    // CHECK: krnl.iterate(%{{.*}}) with (%{{.*}} -> %{{.*}} = #{{.*}}(%{{.*}}, %{{.*}}) to #{{.*}}(%{{.*}}, %{{.*}})) {
+    krnl.iterate(%ok) with (%ik -> %k = (d0, d1)->(d0 - d1)(%i, %j) to (d0, d1)->(d0 + d1)(%i, %j)) {
+
+    }
+
+    // GENERIC: "krnl.iterate"(%{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}}) ( {
+    // GENERIC-NEXT: ^bb0(%{{.*}}: index):
+    // CHECK: krnl.iterate(%{{.*}}) with (%{{.*}} -> %{{.*}} = max #map{{.*}}(%{{.*}}, %{{.*}}) to min #map{{.*}}(%{{.*}}, %{{.*}})[%{{.*}}]) {
+    krnl.iterate(%ok) with (%ik -> %k = max (d0, d1)->(d0 - d1, 0)(%i, %j) to min (d0, d1)[s0]->(d0 + d1, s0)(%i, %j)[%N]) {
+
+    }
+  }
+
+  return
+}