[llvm] [mlir] [mlir][bufferization] Add `BufferViewFlowOpInterface` (PR #78718)

[Uday Bondhugula via llvm-commits]

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@@ -0,0 +1,67 @@
+//===-- BufferViewFlowOpInterface.td - Buffer View Flow ----*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef BUFFER_VIEW_FLOW_OP_INTERFACE
+#define BUFFER_VIEW_FLOW_OP_INTERFACE
+
+include "mlir/IR/OpBase.td"
+
+def BufferViewFlowOpInterface :
+    OpInterface<"BufferViewFlowOpInterface"> {
+  let description = [{
+    An op interface for the buffer view flow analysis. This interface describes
+    buffer dependencies between operands and op results/region entry block
+    arguments.
+  }];
+  let cppNamespace = "::mlir::bufferization";
+  let methods = [
+      InterfaceMethod<
+        /*desc=*/[{
+          Populate buffer dependencies between operands and op results/region
+          entry block arguments.
+
+          Implementations should register dependencies between an operand ("X")
+          and an op result/region entry block argument ("Y") if Y may depend
+          on X. Y depends on X if Y and X are the same buffer or if Y is a
+          subview of X.
+
+          Example:
+          ```
+          %r = arith.select %c, %m1, %m2 : memref<5xf32>
+          ```
+          In the above example, %0 may depend on %m1 or %m2 and a correct
+          interface implementation should call:
+          - "registerDependenciesFn(%m1, %r)".
+          - "registerDependenciesFn(%m2, %r)"
+        }],
+        /*retType=*/"void",
+        /*methodName=*/"populateDependencies",
+        /*args=*/(ins
+            "::mlir::bufferization::RegisterDependenciesFn"
+                :$registerDependenciesFn)
+      >,
+      InterfaceMethod<
+        /*desc=*/[{
+          Return "true" if the given value is a terminal buffer. A buffer value
+          is "terminal" if it cannot be traced back any further in the buffer
+          view flow analysis. E.g., because the value is a newly allocated
+          buffer or because there is not enough information available.
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bondhugula wrote:

Isn't this already covered by `hasSingleEffect<Effect::Allocate>(...)`? Do you have an example where the latter isn't sufficient?

https://github.com/llvm/llvm-project/pull/78718