[flang-commits] [flang] [flang] Catch impure calls in nested concurrent-headers (PR #102075)

[via flang-commits]

harishch4 wrote:

HI @klausler,

Shouldn't we treat DO CONCURRENT with multiple concurrent controls as nested loops and throw an error when impure functions are accessed, since we are generating nested DO loops in HLFIR?


```
do concurrent(i=1:n, j=1:impure(n*m, n/m))
        a(i) = j
end do
```

```
fir.do_loop %arg1 = %44 to %46 step %c1 unordered {
    ...
    fir.do_loop %arg2 = %48 to %58 step %c1_4 unordered {
        ...
    }
}
```
full example: https://godbolt.org/z/KeGxMsEn6

https://github.com/llvm/llvm-project/pull/102075