<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/218760>218760</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Flang][OpenMP] DO CONCURRENT device conversion aborts on arrays with nested derived-type components
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            flang,
            crash-on-valid,
            flang:fir-hlfir,
            flang:openmp
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          MattPD
      </td>
    </tr>
</table>

<pre>
    ### Description

Flang aborts while converting a valid `DO CONCURRENT` loop to OpenMP device constructs when an array element contains a component whose type is another derived type.

The conversion reaches the following `TODO` while inspecting the nested derived-type component:

https://github.com/llvm/llvm-project/blob/6120eb5267a8643dd399f8858b6c92f23a846551/flang/lib/Optimizer/OpenMP/DoConcurrentConversion.cpp#L599-L627

### Reproducer

```fortran
program nested_derived
  implicit none

  type :: inner_t
    integer :: x
  end type

  type :: outer_t
 type(inner_t) :: member
  end type

  type(outer_t) :: a(4)
  integer :: i

  do concurrent (i = 1:4)
    a(i)%member%x = i
  end do

  if (any(a%member%x /= [1, 2, 3, 4])) error stop 1
end program
```

### Command

```console
flang -c -fopenmp -fdo-concurrent-to-openmp=device \
  --offload-arch=gfx908 nested-derived.f90
```

### Result

```text
error: loc("nested-derived.f90":12:20): ../llvm-project/flang/lib/Optimizer/OpenMP/DoConcurrentConversion.cpp:615: not yet implemented: Nested record types are not supported yet.
LLVM ERROR: aborting
```

The reproducer uses no allocatable or pointer components and no procedure calls.

The abort happens at compile time, so reproducing it needs no GPU. The same reproducer compiles successfully with `-fdo-concurrent-to-openmp=host`.

### Expected behavior

Flang should map nested derived-type components or emit an unsupported-feature diagnostic. The compiler should not abort with `LLVM ERROR`.

### Version

The failure was reproduced with Flang 24.0.0git at `00890d9f885989008a8cb5cf5f5335f6f385dbd4` while compiling for AMDGPU. The permalinks above point at upstream commit `6120eb5267a8643dd399f8858b6c92f23a846551`, which still contains the same `TODO`.

### Motivation

The portability study [Portability of Fortran's `do concurrent` on GPUs II](https://arxiv.org/abs/2608.20586) names MAS as its next target beyond POT3D. MAS is a larger application that uses derived types. The paper does not establish whether MAS uses nested derived types. The minimal case still exposes a general device-conversion gap.

</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJykVt1u2zoSfhr6ZiCDpixZuvCFG9eLAzRNkO05twUljSzuUqRAUk68T78YSv5JWgS7OECg1iTn75uZb0Z6r44GccuyLyzbL-QYOuu2jzKE5_2iss15y0Q6_cEefe3UEJQ1jO8Y3x20NEeQlXXBw2unNEJtzQldUHQOJ6lVAyzn-yd4ePr-8OfLy9fvP1jOQVs7QLDwNKB5fIYGT6qOwj64sY7a0IA0IJ2TZ0CNPZpAD4JUxoOE2vaDNXT42lmPEM4DgvIgjQ0dOmjQqRM28Xw5ufuju_jnlTXgUNYdeggdQmu1tq_kNcv5j6f9Ezk5RaSMH7COEdFLgz5gc1GfRLNXX1i6m0x1IQyefokDE4ejCt1YLWvbM3HQ-nT5Jxmc_RfWgYlDpW3FxCFfCY5VJvKNLPJ12jRpWbZFkRVVXpeiFaks1nmWrZg4tAQ-KVIk-DQE1av_oIv_J1CZOOztgzX16Bya8HANfFkPAxPpt6wsk2-52Ewe39L8goOzzVijm29yPv211gUnKfeDs0cn-xmMnzMYjO8AVD9oVasAxhqcFMCUHIIj3YEyBt3PEM8BlAl4RHe5fIvHaKa8_U7cjuEiHp-I4qJQlJc3PfZV9P73qpgoLlpuMpKJYs1EOQXx3it1kW4sFdCMKJBtYOkeVizdXWUhqlL0U2SzJyJ7iw_V1afGXnSqlhRJc6bvBxFxICmWfVkx8QCCPil91izbRwMloHPWgQ92gBXjO9I9Z-c-dR9z_GD7XprmQ4Kp_6wmrGJxQVJD0toBTT9A0jY2uQWfBJtMNyzdz-3LsocYUZLYttVWNol0dcfS_bF9K3kxV0syV8uyLflnLr6gH3X44GHANzqKQVNmtK2ZKJgQv9EtBEt3K_oITmClO1guf-28v9dH6S5fZaTa2ABnDLH-I1lhQ8ffJ7pwWFs3VaIH6TA-9-MwWEfXZwzEUd--_fUIX19enl5iRRKvKnP8FSQiMnftUhg9ejAWpNa2lkFWGsE6GCyVsbuxE5FjQw8HZ2tsRodQS639HT1Gm9DJYUBi2RCFiQWD6pEqz9urZWJE6nPEJpr_x_OfSyAlXvbv_Jt1ePBjXaP37aj1GV5V6IhtPyuszvrAcr78WBtf34iSsYEKO3lS1t3PI9_ZUTfQy-FzsvYEEvYq0JwZzTUbSYsyEDiNkkdjfVD1FNcch7tYoBxOgF1iuUvgb7z-a6qbG9qtVJoMvUp_w6uZtE2xiPWSL_mRfAxkgPOi5E0cCWVRcl7Ioq6yus3aLE2zNm_TImuqZn0bX5PTlKvWOtg97q9pGtD1Uivzb09RnHAqGDI0Dj44lD0JEz4s5__zYMo5lclrp-oOfFBa34Z2uNTGbcb-gtGjDeokwzuYKC2yUlqFM_gwNmdixOe7Q9vCYZ5NYuNJ_TuiJjCsofr08McfkTqL9wNaujd1WlpHPCArz8RB5LxYCp4VOZGskT16eNz9E6QHFTwYfAsQpDtigArP1jTw_PQj3S_jI1pDQNOtAznQPIwRQegIXOrW--3Ez-mQA60tNvZyAPTUyMp3tArFjYY0T63-rqrvdfTKqF5qqKXHGX18GywJSTiiQSf1vGwld5vQUQ6UiEWzTZsyLeUCt6tNscmLYpWKRbfdtE2NVVav-JqnVZOt5Xqz2VTFpipW1aqqFmorOCEmMsG5WK2WeZthmZebtkAsN5uUrTn2UuklkS8BvVDej7gVq2KT84WWFWofl1AhZkKmaceEqJ30XWJNEpfJ6_H0KN21yiWdbpX75WYmESFor3XbyPrVePRszbXywd9cCSrouAHHnqP6yL7M3J_t4d3uerepXsCb118776p-at_PmWcxOr39v3fECFkszgm101b8NwAA___54MI0">