Re: OpenACC 2.7: front-end support for readonly modifier: Add basic OpenACC 'declare' testing

[Tobias Burnus <tburnus@baylibre.com>]

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Hi all, hi Thomas & Chung-Lin,

Thomas Schwinge wrote:
> But I realized another thing: don't we have to handle the 'readonly'
> modifier also in Fortran module files, that is, next to the OpenACC
> 'declare' 'copyin' handling in 'gcc/fortran/module.cc':
> 'AB_OACC_DECLARE_COPYIN' etc.?

I bet so; it is not as bad as with the others as it is "only" an 
optimization hint, but it makes sense to make it available.

Note that when you place the 'module' in the same file as the module 
users ('use'), the compiler might know things because they are in the 
same translation unit / file not because it is in the module ...

>   Chung-Lin, please check, via test cases.
> 'gfortran.dg/goacc/routine-module*', for example, should provide some
> guidance of how to achieve actual module file use, and then do the same
> 'scan-tree-dump' as in the current 'readonly' modifier test cases.
...
> By means of only emitting a tag
> in the module file if the 'readonly' modifier is specified, we should
> maintain compatibility with the current 'MOD_VERSION'.

That was the idea: If only new information gets added (if used), older 
compilers still work. This has huge limitations and does not work as 
well as imagined but here it should work: Older .mod will work with new 
compilers, even though the reverse might not be true.

Tobias