[llvm] [mlir][bufferization] Generalize tensor slice rules to subset ops (PR #65619)

[Martin Erhart via llvm-commits]

================
@@ -1147,13 +1023,72 @@ struct SplatOpInterface
   }
 };
 
+namespace {
+/// Return "true" if `insertSliceOp` inserts into a subset that is equivalent
+/// to the subset defined by `candidate`. `equivalenceFn` is used to determine
+/// equivalence of tensors.
+template <typename OpTy>
+bool isSubsetEquivalentToInsertSliceLikeOp(
+    OpTy insertSliceOp, Value candidate,
+    function_ref<bool(Value, Value)> equivalenceFn) {
+  // Look for a matching tensor.extract_slice op.
+  auto extractSliceOp = candidate.getDefiningOp<tensor::ExtractSliceOp>();
+  if (!extractSliceOp)
+    return false;
+  if (!equivalenceFn(extractSliceOp.getSource(), insertSliceOp.getDest()))
+    return false;
+  if (!sameOffsetsSizesAndStrides(extractSliceOp, insertSliceOp,
+                                  isEqualConstantIntOrValue))
+    return false;
+  return true;
----------------
maerhart wrote:

```suggestion
  return sameOffsetsSizesAndStrides(extractSliceOp, insertSliceOp,
                                  isEqualConstantIntOrValue);
```

https://github.com/llvm/llvm-project/pull/65619