[llvm-branch-commits] [flang] [flang] Skip processing reductions for unstructured `do concurrent` loops (PR #150188)

[Tom Eccles via llvm-branch-commits]

https://github.com/tblah commented:

This does seem like a reasonable approach.

What do you think about the following program:
```
program test
integer i,r

do concurrent (i=1:10) reduce(+:r)
  r = 1
enddo

print *,r
end
```

As I understand it, this should print the number of threads the loop actually used (because that will be the number of threadprivate values of `r` which were created). This would make something like what is done here user-visible. But I guess that is okay because the standard does not seem to require that do concurrent is actually run over multiple threads?

https://github.com/llvm/llvm-project/pull/150188