[flang-commits] [flang] [mlir] [RFC][mlir] ViewLikeOpInterface method for detecting partial views. (PR #164020)

[Slava Zakharin via flang-commits]

================
@@ -23,21 +23,45 @@ def ViewLikeOpInterface : OpInterface<"ViewLikeOpInterface"> {
   }];
   let cppNamespace = "::mlir";
 
-  let methods = [
-    InterfaceMethod<
-      "Returns the source buffer from which the view is created.",
-      "::mlir::Value", "getViewSource">,
-    InterfaceMethod<
-      /*desc=*/[{ Returns the buffer which the view created. }],
-      /*retTy=*/"::mlir::Value",
-      /*methodName=*/"getViewDest",
-      /*args=*/(ins),
-      /*methodBody=*/"",
-      /*defaultImplementation=*/[{
+  let methods =
+      [InterfaceMethod<
+           "Returns the source buffer from which the view is created.",
+           "::mlir::Value", "getViewSource">,
+       InterfaceMethod<
+           /*desc=*/[{ Returns the buffer which the view created. }],
+           /*retTy=*/"::mlir::Value",
+           /*methodName=*/"getViewDest",
+           /*args=*/(ins),
+           /*methodBody=*/"",
+           /*defaultImplementation=*/[{
         return $_op->getResult(0);
-      }]
-    >
-  ];
+      }]>,
+       InterfaceMethod<
+           /*desc=*/
+           [{ Returns true iff the source buffer and the resulting view start at the same "address". }],
+           /*retTy=*/"bool",
+           /*methodName=*/"isSameStart",
+           /*args=*/(ins),
+           /*methodBody=*/"",
+           /*defaultImplementation=*/[{
+        return false;
----------------
vzakhari wrote:

I added the default implementations so that they are conservatively correct, assuming that the methods will be used to perform some transformations based on the fact that a view starts at the same address as the source or/and a view is a complete view of the source.

Maybe, the names of the methods are confusing.  Would it be more clear if I named them `knownToHaveSameStart` and `knownToBeCompleteView`?  The idea is that when the methods return `false`, one cannot assume whether the view have or not have the same start, etc.

https://github.com/llvm/llvm-project/pull/164020