[Mlir-commits] [mlir] Add examples for reinterpret_cast and subview operators to show their behavior in relation to their input memref underlying memory and view (PR #135244)

[Matthias Springer]

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@@ -1363,6 +1363,58 @@ def MemRef_ReinterpretCastOp
     %dst.sizes = %sizes
     %dst.strides = %strides
     ```
+
+    Example 2:
+
+    Consecutive `reinterpret_cast` operations on memref's with static dimensions.
+
+    We distinguish between *underlying memory* — the sequence of elements as
+    they appear in the contiguous memory of the memref — and the *view*, which refers to
+    the underlying memory interpreted according to specified offsets, sizes, and strides.
+
+    ```mlir
+    %result1 = memref.reinterpret_cast %arg0 to offset: [9], sizes: [4, 4], strides: [16, 2] : memref<8x8xf32, strided<[8, 1], offset: 0>> to memref<4x4xf32, strided<[16, 2], offset: 9>>
+
+    %result2 = memref.reinterpret_cast %result1 to offset: [0], sizes: [2, 2], strides: [4, 2] : memref<4x4xf32, strided<[16, 2], offset: 9>> to memref<2x2xf32, strided<[4, 2], offset: 0>>
+    ```
+
+    The input memref `%arg0` has the following view. The underlying memory consists
----------------
matthias-springer wrote:

maybe rephrase something like this? `The underlying memory consists of a linear sequence of integers from 1 to 64. The  memref %arg0 has the following 8x8 elements:`

https://github.com/llvm/llvm-project/pull/135244