[Mlir-commits] [mlir] [mlir][emitc] make CExpression trait into interface (PR #142771)

[Simon Camphausen]

================
@@ -0,0 +1,48 @@
+//===- EmitCInterfaces.td - EmitC Interfaces ---------------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the interfaces used by EmitC.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_EMITC_IR_EMITCINTERFACES
+#define MLIR_DIALECT_EMITC_IR_EMITCINTERFACES
+
+include "mlir/IR/OpBase.td"
+
+def CExpressionInterface : OpInterface<"CExpressionInterface"> {
+  let description = [{
+    Interface to mark operations that can be part of the CExpression.
+  }];
+
+  let cppNamespace = "::mlir::emitc";
+  let methods = [
+    InterfaceMethod<[{
+      Check whether operation has side effects that may affect the expression
+      evaluation.
+
+      By default operation is marked as not having any side effects.
+
+      ```c++
+      class ConcreteOp ... {
+      public:
+        bool hasSideEffects() {
+          // That way we can override the default implementation.
+          return true;
+        }
+      };
+      ```
+    }],
+      "bool", "hasSideEffects", (ins), /*methodBody=*/[{}],
+       /*defaultImplementation=*/[{
+        return false;
----------------
simon-camp wrote:

Can you make this return true by default? Then you can add and implement the interface directly on `EmitC_UnaryOp` and `EmitC_BinaryOp` to override the default. 

https://github.com/llvm/llvm-project/pull/142771