[Mlir-commits] [mlir] [mlir] Implement memory-space cast operand fusion into consumers (PR #159454)

[Mehdi Amini]

================
@@ -0,0 +1,114 @@
+//===- MemOpInterfaces.td - Memory operation 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 contains interfaces for operations that interact with memory.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_INTERFACES_MEMOPINTERFACES_TD
+#define MLIR_INTERFACES_MEMOPINTERFACES_TD
+
+include "mlir/IR/OpBase.td"
+include "mlir/Interfaces/SideEffectInterfaces.td"
+
+def FuseMemorySpaceCastConsumerOpInterface :
+    OpInterface<"FuseMemorySpaceCastConsumerOpInterface"> {
+  let description = [{
+    An interface to fuse memory-space cast operands into a consumer operation.
+    It is the responsibility of the interface to determine which casts can be
+    fused into the operation.
+  }];
+  let cppNamespace = "::mlir";
+  let methods = [
+    InterfaceMethod<[{
+        Attempt to fuse the incoming cast-like operands. Returns `success`
+        and any new results on fusion success, otherwise it returns failure.
+        If new results are produced, these must be compatible with the original
+        operation results.
+
+        The `modifiedInPlace` parameter indicates whether the operation was
+        modified in place. If `false` and the fusion succeeded, then the
+        interface guarantees it is valid to erase the original operation.
+        If `true`, then the interface must guarantee no operations were created
+        by the method, and that no further IR modification is necessary. It is
+        considered an error if `modifiedInPlace` is true and the fusion failed.
+
+        Any implementations of this method must not erase/replace the original
+        operation, instead it is the caller responsibility to erase or replace
+        the op with the results provided by the method.
+
+        Finally, any implementations of this method have to guarantee that the
+        IR remains valid at all times.
+      }],
+      "::llvm::FailureOr<::llvm::SmallVector<::mlir::Value>>", "fuseCastOperands",
+      (ins "::mlir::OpBuilder &":$builder, "bool &":$modifiedInPlace)
----------------
joker-eph wrote:

Why don't you return a tuple instead of this output argument?

https://github.com/llvm/llvm-project/pull/159454