[mlir][EmitC] Add Arith to EmitC conversions

This adds patterns and a pass to convert the Arith dialect to EmitC.
For now, this covers arithemtic binary ops operating on floating point
types.

It is not checked within the patterns whether the types, such as the
Tensor type, are supported in the respective EmitC operations. If
unsupported types should be converted, the conversion will fail anyway
because no legal EmitC operation can be created. This can clearly be
improved in a follow up, also resulting in better error messages.
Functions for such checks should not solely be used in the conversions
and should also be (re)used in the verifier.

Author: marbre

mlir/include/mlir/Conversion/Passes.h

@@ -13,6 +13,7 @@
 #include "mlir/Conversion/AffineToStandard/AffineToStandard.h"
 #include "mlir/Conversion/ArithToAMDGPU/ArithToAMDGPU.h"
 #include "mlir/Conversion/ArithToArmSME/ArithToArmSME.h"
+#include "mlir/Conversion/ArithToEmitC/ArithToEmitCPass.h"
 #include "mlir/Conversion/ArithToLLVM/ArithToLLVM.h"
 #include "mlir/Conversion/ArithToSPIRV/ArithToSPIRV.h"
 #include "mlir/Conversion/ArmNeon2dToIntr/ArmNeon2dToIntr.h"

mlir/include/mlir/Conversion/Passes.td

@@ -133,6 +133,15 @@ def ArithToAMDGPUConversionPass : Pass<"convert-arith-to-amdgpu"> {
   ];
 }
 
+//===----------------------------------------------------------------------===//
+// ArithToEmitC
+//===----------------------------------------------------------------------===//
+
+def ConvertArithToEmitC : Pass<"convert-arith-to-emitc", "ModuleOp"> {
+  let summary = "Convert Arith dialect to EmitC dialect";
+  let dependentDialects = ["emitc::EmitCDialect"];
+}
+
 //===----------------------------------------------------------------------===//
 // ArithToLLVM
 //===----------------------------------------------------------------------===//

mlir/lib/Conversion/ArithToEmitC/ArithToEmitC.cpp

@@ -0,0 +1,59 @@
+//===- ArithToEmitC.cpp - Arith to EmitC Patterns ---------------*- 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 file implements patterns to convert the Arith dialect to the EmitC
+// dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Conversion/ArithToEmitC/ArithToEmitC.h"
+
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/EmitC/IR/EmitC.h"
+#include "mlir/Transforms/DialectConversion.h"
+
+using namespace mlir;
+
+//===----------------------------------------------------------------------===//
+// Conversion Patterns
+//===----------------------------------------------------------------------===//
+
+namespace {
+template <typename ArithOp, typename EmitCOp>
+class ArithOpConversion final : public OpConversionPattern<ArithOp> {
+public:
+  using OpConversionPattern<ArithOp>::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(ArithOp arithOp, typename ArithOp::Adaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+
+    rewriter.template replaceOpWithNewOp<EmitCOp>(arithOp, arithOp.getType(),
+                                                  adaptor.getOperands());
+
+    return success();
+  }
+};
+} // namespace
+
+//===----------------------------------------------------------------------===//
+// Pattern population
+//===----------------------------------------------------------------------===//
+
+void mlir::populateArithToEmitCPatterns(RewritePatternSet &patterns) {
+  MLIRContext *ctx = patterns.getContext();
+
+  // clang-format off
+  patterns.add<
+    ArithOpConversion<arith::AddFOp, emitc::AddOp>,
+    ArithOpConversion<arith::DivFOp, emitc::DivOp>,
+    ArithOpConversion<arith::MulFOp, emitc::MulOp>,
+    ArithOpConversion<arith::SubFOp, emitc::SubOp>
+  >(ctx);
+  // clang-format on
+}

mlir/lib/Conversion/ArithToEmitC/ArithToEmitCPass.cpp

@@ -0,0 +1,47 @@
+//===- ArithToEmitCPass.cpp - Func to EmitC Pass ----------------*- 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 file implements a pass to convert the Arith dialect to the EmitC
+// dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Conversion/ArithToEmitC/ArithToEmitCPass.h"
+
+#include "mlir/Conversion/ArithToEmitC/ArithToEmitC.h"
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/EmitC/IR/EmitC.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Transforms/DialectConversion.h"
+
+namespace mlir {
+#define GEN_PASS_DEF_CONVERTARITHTOEMITC
+#include "mlir/Conversion/Passes.h.inc"
+} // namespace mlir
+
+using namespace mlir;
+
+namespace {
+struct ConvertArithToEmitC
+    : public impl::ConvertArithToEmitCBase<ConvertArithToEmitC> {
+  void runOnOperation() override;
+};
+} // namespace
+
+void ConvertArithToEmitC::runOnOperation() {
+  ConversionTarget target(getContext());
+
+  target.addLegalDialect<emitc::EmitCDialect>();
+
+  RewritePatternSet patterns(&getContext());
+  populateArithToEmitCPatterns(patterns);
+
+  if (failed(
+          applyPartialConversion(getOperation(), target, std::move(patterns))))
+    signalPassFailure();
+}

mlir/lib/Conversion/ArithToEmitC/CMakeLists.txt

@@ -0,0 +1,16 @@
+add_mlir_conversion_library(MLIRArithToEmitC
+  ArithToEmitC.cpp
+  ArithToEmitCPass.cpp
+
+  ADDITIONAL_HEADER_DIRS
+  ${MLIR_MAIN_INCLUDE_DIR}/mlir/Conversion/ArithToEmitC
+
+  DEPENDS
+  MLIRConversionPassIncGen
+
+  LINK_LIBS PUBLIC
+  MLIRArithDialect
+  MLIREmitCDialect
+  MLIRPass
+  MLIRTransformUtils
+  )

mlir/lib/Conversion/CMakeLists.txt

@@ -3,6 +3,7 @@ add_subdirectory(AMDGPUToROCDL)
 add_subdirectory(ArithCommon)
 add_subdirectory(ArithToAMDGPU)
 add_subdirectory(ArithToArmSME)
+add_subdirectory(ArithToEmitC)
 add_subdirectory(ArithToLLVM)
 add_subdirectory(ArithToSPIRV)
 add_subdirectory(ArmNeon2dToIntr)

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

@@ -4011,6 +4011,7 @@ cc_library(
         ":AffineToStandard",
         ":ArithToAMDGPU",
         ":ArithToArmSME",
+        ":ArithToEmitC",
         ":ArithToLLVM",
         ":ArithToSPIRV",
         ":ArmNeon2dToIntr",
@@ -8156,6 +8157,32 @@ cc_library(
     ],
 )
 
+cc_library(
+    name = "ArithToEmitC",
+    srcs = glob([
+        "lib/Conversion/ArithToEmitC/*.cpp",
+        "lib/Conversion/ArithToEmitC/*.h",
+    ]),
+    hdrs = glob([
+        "include/mlir/Conversion/ArithToEmitC/*.h",
+    ]),
+    includes = [
+        "include",
+        "lib/Conversion/ArithToEmitC",
+    ],
+    deps = [
+        ":ArithDialect",
+        ":ConversionPassIncGen",
+        ":EmitCDialect",
+        ":IR",
+        ":Pass",
+        ":Support",
+        ":TransformUtils",
+        ":Transforms",
+        "//llvm:Support",
+    ],
+)
+
 cc_library(
     name = "ArithToLLVM",
     srcs = glob(["lib/Conversion/ArithToLLVM/*.cpp"]),