[TorchToLinalg] torch-mlir fails to legalize torch.aten.empty_permuted

[prasadakp27]

Torch-mlir fails with the following error when running the test case below:

error: failed to legalize operation 'torch.operator' that was explicitly marked illegal: %5 = "torch.operator"(%3, %4, %0, %2, %2, %2) <{name = "torch.aten.empty_permuted"}> : (!torch.list, !torch.list, !torch.int, !torch.none, !torch.none, !torch.none) -> !torch.vtensor<[4],si64>

Context: Appears in MoE routing / argsort paths. Allocates an uninitialized tensor with a logical size but stored in a chosen physical_layout dimension order.

Command to reproduce:

torch-mlir-opt -pass-pipeline='builtin.module(func.func(torch-match-quantized-custom-ops), torchdynamo-export-to-torch-backend-pipeline{extra-library=})' test_empty_permuted.mlir
test_empty_permuted.mlir:

module {
  func.func @forward() -> !torch.vtensor<[4],si64> {
    %int4 = torch.constant.int 4
    %int0 = torch.constant.int 0
    %none = torch.constant.none
    %0 = torch.prim.ListConstruct %int4 : (!torch.int) -> !torch.list<int>
    %1 = torch.prim.ListConstruct %int0 : (!torch.int) -> !torch.list<int>
    %2 = torch.constant.int 4
    %3 = "torch.operator"(%0, %1, %2, %none, %none, %none) <{name = "torch.aten.empty_permuted"}> : (!torch.list<int>, !torch.list<int>, !torch.int, !torch.none, !torch.none, !torch.none) -> !torch.vtensor<[4],si64>
    return %3 : !torch.vtensor<[4],si64>
  }

[rhanqtl]

I'd like to work on this.