[flang-commits] [flang] [flang] Set SAVE attribute for EQUIVALENCEd symbols consistently. (PR #67078)

[Slava Zakharin via flang-commits]

vzakhari wrote:

It looks like the code formatting check is broken for some other PRs, so it should not be my problem.

More extensive testing uncovered the following problem.

```
module equiv
  real dx,dy
  common /blk/ dx
  equivalence(dx,dy)
end module
```

With my changes I get the following module file:
```
module equiv
real(4),save::dx
real(4),save::dy
common/blk/dx
equivalence(dx,dy)
end
```

So the `SAVE` was explicitly printed, which causes `error: The entity 'dx' in COMMON block /blk/ may not have an explicit SAVE attribute` when the module is used.

I am planning to filter out the implicit `SAVE` in `mod-file.cpp`, but please let me know if I am on a wrong path.

https://github.com/llvm/llvm-project/pull/67078