[Torch Dialect] add missing one_hot dtype function (#2143)

* [Torch Dialect] add missing one_hot dtype function

* update

* update

* update

lib/Dialect/Torch/Transforms/AbstractInterpLibrary.cpp

@@ -9548,6 +9548,20 @@ StringRef mlir::torch::Torch::getAbstractInterpLibrary() {
 "    %7 = torch.prim.TupleConstruct %0#1, %0#1, %6 : !torch.int, !torch.int, !torch.int -> !torch.tuple<int, int, int>\n"
 "    return %7 : !torch.tuple<int, int, int>\n"
 "  }\n"
+"  func.func @\"__torch_mlir_dtype_fn.aten.one_hot\"(%arg0: !torch.tuple<int, int>, %arg1: !torch.int) -> !torch.int {\n"
+"    %none = torch.constant.none\n"
+"    %str = torch.constant.str \"AssertionError: \"\n"
+"    %int4 = torch.constant.int 4\n"
+"    %0:2 = torch.prim.TupleUnpack %arg0 : !torch.tuple<int, int> -> !torch.int, !torch.int\n"
+"    %1 = torch.aten.eq.int %0#1, %int4 : !torch.int, !torch.int -> !torch.bool\n"
+"    torch.prim.If %1 -> () {\n"
+"      torch.prim.If.yield\n"
+"    } else {\n"
+"      torch.prim.RaiseException %str, %none : !torch.str, !torch.none\n"
+"      torch.prim.If.yield\n"
+"    }\n"
+"    return %int4 : !torch.int\n"
+"  }\n"
 "  func.func @\"__torch_mlir_dtype_fn.aten.native_batch_norm\"(%arg0: !torch.tuple<int, int>, %arg1: !torch.optional<tuple<int, int>>, %arg2: !torch.optional<tuple<int, int>>, %arg3: !torch.optional<tuple<int, int>>, %arg4: !torch.optional<tuple<int, int>>, %arg5: !torch.bool, %arg6: !torch.float, %arg7: !torch.float) -> !torch.tuple<int, int, int> {\n"
 "    %int6 = torch.constant.int 6\n"
 "    %0:2 = torch.prim.TupleUnpack %arg0 : !torch.tuple<int, int> -> !torch.int, !torch.int\n"

lib/Dialect/Torch/Transforms/DecomposeComplexOps.cpp

@@ -4313,7 +4313,6 @@ class DecomposeAtenOneHotOp : public OpRewritePattern<AtenOneHotOp> {
       return rewriter.notifyMatchFailure(
           op, "unimplemented: num_classes must be constant");
     Value none = rewriter.create<ConstantNoneOp>(loc);
-    Value falseValue = rewriter.create<ConstantBoolOp>(loc, false);
 
     // arange tensor
     auto si64Type = IntegerType::get(context, 64, IntegerType::Signed);
@@ -4341,11 +4340,7 @@ class DecomposeAtenOneHotOp : public OpRewritePattern<AtenOneHotOp> {
         loc, eqType, unsqueezeTensor, arangeTensor);
 
     // convert to si64
-    Value si64TypeValue =
-        Torch::getDtypeIntValueForType(rewriter, loc, si64Type);
-    Value result = rewriter.create<AtenToDtypeOp>(
-        loc, op.getType(), eqTensor, si64TypeValue, /*non_blocking=*/falseValue,
-        /*copy=*/falseValue, /*memory_format=*/none);
+    Value result = convertTensorToDtype(rewriter, loc, eqTensor, si64Type);
     rewriter.replaceOp(op, result);
     return success();
   }

python/torch_mlir/dialects/torch/importer/jit_ir/build_tools/abstract_interp_lib_gen.py

@@ -2699,6 +2699,13 @@ def aten〇native_layer_norm〡dtype(input_rank_dtype: Tuple[int, int], normaliz
         result_dtype = torch.float64
     return input_dtype, input_dtype, result_dtype
 
+# note: one_hot doesn't support "meta" device, use "cpu" instead.
+@check_dtype_function(_check_tensors_with_the_same_dtype(num_of_tensors=1, num_classes=2, tensor_device="cpu", error_types={torch.complex128, torch.complex64, torch.float64, torch.float32, torch.float16, torch.bfloat16, torch.int32, torch.int16, torch.int8, torch.uint8, torch.bool}))
+def aten〇one_hot〡dtype(self_rank_dtype: Tuple[int, int], num_classes: int = -1) -> int:
+    self_rank, self_dtype = self_rank_dtype
+    assert self_dtype == torch.int64
+    return torch.int64
+
 @check_dtype_function(
     [Invocation(TensorOfShape(3, 3, dtype=torch.float32), TensorOfShape(3, dtype=torch.float32),
                 TensorOfShape(3, dtype=torch.float32), TensorOfShape(3, dtype=torch.float32),