[mlir] [llvm] [mlir][EmitC] Add func, call and return operations and conversions (PR #79612)

[Jacques Pienaar via llvm-commits]

================
@@ -0,0 +1,118 @@
+//===- FuncToEmitC.cpp - Func 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 Func dialect to the EmitC
+// dialect.
+//
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Conversion/FuncToEmitC/FuncToEmitC.h"
+
+#include "mlir/Dialect/EmitC/IR/EmitC.h"
+#include "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Transforms/DialectConversion.h"
+
+using namespace mlir;
+
+//===----------------------------------------------------------------------===//
+// Conversion Patterns
+//===----------------------------------------------------------------------===//
+
+namespace {
+class CallOpConversion final : public OpConversionPattern<func::CallOp> {
+public:
+  using OpConversionPattern<func::CallOp>::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(func::CallOp callOp, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    // Multiple results func was not converted to `emitc.func`.
+    if (callOp.getNumResults() > 1)
+      return rewriter.notifyMatchFailure(
+          callOp, "Only functions with zero or one result can be converted");
----------------
jpienaar wrote:

s/O/o/ (lets follow the error convention for notifications too) 

https://github.com/llvm/llvm-project/pull/79612