[mlir][shape] add value_of op

[jpienaar]

Thanks, makes sense to have the peer function. Just some doc updates here.

mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td

647

It need not be a tensor.

One could also mention this is the peer of shape_of.

648

I think lets add here and to ShapeOfOp that behavior is UB if input is error.

[yaochengji]

update the description

mlir/include/mlir/Dialect/Shape/IR/ShapeOps.td

def Shape_ShapeOfOp : Shape_Op<"shape_of",
 
   let extraClassDeclaration = [{
     // Returns when two result types are compatible for this op; method used by
     // InferTypeOpInterface
     static bool isCompatibleReturnTypes(TypeRange l, TypeRange r);
   }];
 }
 
+def Shape_ValueOfOp : Shape_Op<"value_of", [NoSideEffect]> {
+  let summary = "Returns value of a !shape.value_shape operand";
+
+   let description = [{
+    The operation takes !shape.value_shape, a.k.a. (value, shape) tuple as an
+    argument, and returns its value. The behavior is undefined for unknown and
+    invalid arguments.
+  }];
+
+  let arguments = (ins Shape_ValueShapeType:$arg);
+  let results = (outs AnyShaped:$result);
+
+  let assemblyFormat = "$arg attr-dict `:` type($result)";
+}
+
 def Shape_SizeToIndexOp : Shape_Op<"size_to_index", [
     DeclareOpInterfaceMethods<CastOpInterface>, NoSideEffect
   ]> {
   let summary = "Casts between index types of the shape and standard dialect";
   let description = [{
     Converts a `shape.size` to a standard index. This operation and its
     inverse, `index_to_size`, facilitate index conversion between the standard
     and the shape dialect. The behavior is undefined for unknown and invalid

mlir/test/Dialect/Shape/ops.mlir

func.func @test_parse_const_shape() {
   return
 }
 
 func.func @test_shape_of(%arg0: tensor<?xf32>) -> tensor<?xindex> {
   %0 = shape.shape_of %arg0 : tensor<?xf32> -> tensor<?xindex>
   return %0 : tensor<?xindex>
 }
 
+func.func @test_value_of(%arg0: !shape.value_shape) -> tensor<?xf32> {
+  %0 = shape.value_of %arg0 : tensor<?xf32>
+  return %0 : tensor<?xf32>
+}
+
 func.func @test_constraints() {
   %0 = shape.const_shape [] : !shape.shape
   %1 = shape.const_shape [1, 2, 3] : !shape.shape
   %true = arith.constant true
   %w0 = shape.cstr_broadcastable %0, %1 : !shape.shape, !shape.shape
   %w1 = shape.cstr_eq %0, %1 : !shape.shape, !shape.shape
   %w2 = shape.const_witness true
   %w3 = shape.const_witness false