[Info-vax] Itanium support is back in GCC 15

[Michael S]

On Mon, 24 Feb 2025 15:08:57 -0500
Arne Vajhøj <arne at vajhoej.dk> wrote:

> On 2/24/2025 12:42 PM, Michael S wrote:
> > On Thu, 7 Nov 2024 16:48:49 -0500
> > Arne Vajhøj <arne at vajhoej.dk> wrote:  
> >> On 11/7/2024 12:33 PM, gcalliet wrote:  
> >>> Le 04/11/2024 à 21:16, Arne Vajhøj a écrit :  
> >>>> I wish someone would volunteer to create VMS support
> >>>> in GCC 16 or whatever!
> >>>>     
> >>> Because I created (canadian method) Gnat Ada (on gcc) for VMS
> >>> Itanium, and because we were on gcc 4.7, there is some work ahead,
> >>> but why not :)
> >>>
> >>> The big issue is the step to gcc 5, where they upgraded to c++
> >>> mode. It is one of the reasons why Adacore didn't continue support
> >>> of gnat ada on VMS in 2015.  
> >>
> >> VMS x86-64 has a better C++ compiler than VMS Itanium.  
> 
> That comment was about C++ standard compliance not performance.
> 

Ok

> C++ VMS x86-64 is clang which in the (older) clang version used
> should mean C++14 while C++ VMS Itanium is very very old (like
> C++ 98 old).
> 
> > According to the benchmarks that you posted here several months (a
> > year?) ago, VMS x86-64 compilers are quite awful comparatively to
> > x86-64 compilers available on Windows/Linux/BSD.
> > Do you want to say that VMS Itanium compilers are worse?  
> 
> I believe the conclusion was that the VMS x86-64 compilers except C++
> was slower than C/C++ on other OS and C++ on VMS.
> 

Somehow I got an impression that C++ compilers were also significantly
slower than C++ compilers on other platforms.
Do I misremember?

> My guess is that it is a combination of the GEM to LLVM translation
> and a desire from VSI to be a little conservative (prioritizing
> correctness over speed).
> 
> Arne
>