<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/88344>88344</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            flang-new: forcing arrays to be allocated on the heap and a possible bug
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    
This is related to https://github.com/llvm/llvm-project/issues/56018. 

According to https://github.com/llvm/llvm-project/issues/56018 , `flang -mmlir -fdynamic-heap-array` should force dynamic arrays to be allocated on the heap.  The example mentioned at https://github.com/llvm/llvm-project/issues/56018 works but the following does not. 

```
! array.f90

module outprod_mod
contains
function outprod(y, z) result(x)
implicit none
real, intent(in) :: y(:), z(:)
real :: x(size(y), size(z))
integer :: i, j, n, m

m = size(y)
n = size(z)
do i = 1, m
    do j = 1, n
        x(i, j) = y(i) * z(j)
    end do
end do
end function
end module outprod_mod

program prog
use outprod_mod, only : outprod
implicit none

integer, parameter :: k = 10000
integer :: i
real :: y(k)
y = 1.0
do i = 1, k
    write (*, *) i, size(outprod(y(1:i), y(1:i)))
end do
end
```

With flang-new, it crashes with a segfault as follows.

```text
$ uname -a && flang --version && flang -fno-stack-arrays -mmlir -fdynamic-heap-array -o array array.f90 && ./array

Linux 6.5.0-26-generic #26~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Mar 12 10:22:43 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
flang-new version 19.0.0git (git@github.com:llvm/llvm-project.git 37c175af955f0aeab67e8c553a0a47b2ed0fdba2)
Target: x86_64-unknown-linux-gnu
Thread model: posix
 ... ...
 1445 2088025
 1446 2090916
 Segmentation fault (core dumped)
```

Questions:

- How to effectively force dynamic arrays to be allocated on the heap? 
- `-fdynamic-heap-array` alone cannot be recognized by the  compiler. It must be `-mmlir -fdynamic-heap-array`. Is this intended?  

Notes: 
- `ulimit -s unlimited` seems to help, but we need a solution on flang's side. 
- Compiled with Classic Flang 15.0.3 without any flags, the code runs fine. 

Thank you for taking a look. 
</pre>
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