[flang] [llvm] [Flang] Adding lowering for the allocation and deallocation of coarrays (PR #182110)

[Dan Bonachea via llvm-commits]

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bonachea wrote:

I don't understand what purpose this `else` case is serving. 

Unless I'm misunderstanding something, the compiler should never be implicitly generating code to automatically deallocate a non-allocatable coarray. Non-allocatable coarrays are  effectively SAVE and never deallocated; also IIUC they should never reach this point once line 688 is corrected. (Here I'm ignoring non-allocatable coarray dummy arguments and associate names, which also never cause coarray deallocation). So I don't see why we'd ever want a `mif::DeallocCoarrayOp` for a non-allocatable coarray.

What is the valid use case that reaches this else case? Perhaps a comment here would help? Or perhaps the else case should just be a fatal error?

https://github.com/llvm/llvm-project/pull/182110