[Info-vax] Future comparison of optimized VSI x86 compilers vs Linux compilers

[Arne Vajhøj]

On 8/4/2020 11:00 AM, John Reagan wrote:
> On Monday, August 3, 2020 at 9:34:33 PM UTC-4, dthi... at gmail.com
> wrote:
>> On Monday, August 3, 2020 at 8:03:44 PM UTC-4, John Reagan wrote:
>>> If I didn't go with clang/LLVM but enhanced GEM, I'd have to not
>>> only track all the hardware variants, I'd have to track all the
>>> C++ language and STL changes.  No thanks.  I'd need 50 people.
>>> With a clang-based environment, I can hope that open source code
>>> can come to OpenVMS with little pain (lets not get into the
>>> mixed-pointer discussion here please).
>> 
>>> And flang actually has lots of VAX Fortran features in it given
>>> that VAX Fortran was the industry standard for a long time.  No,
>>> it doesn't have CDD or /DIAG or /ANAL support, but it has lots of
>>> the language syntax already.  I've in regular communication with
>>> the flang manager.
>> 
>> I was wondering if VSI was going to look at flang to replace the
>> FORTRAN compiler on x86. It seemed to me that getting the
>> open-source community to help keep your compilers up-to-date would
>> be a win-win for keeping language standards compliance high while
>> keeping your cost of development down. Glad to see you are
>> considering getting community support to help keep OpenVMS
>> up-to-date.
> 
> Not "replace" but I'm hoping to provide side-by-side.  Same with
> "clang as a C compiler" will not replace the DEC C frontend/G2L/LLVM
> combo.

Which makes sense. Traditional VMS compiler to support the
existing code. Standard compiler for the new code.

But what if users want to port an application
gradually. Will it work with parts of the application
build with VMS Fortran / VMS C and other parts of the
application build with flang/clang?

Arne