[Info-vax] What would be involved in moving RMS into kernel mode ?

[Arne Vajhøj]

On 5/10/2023 1:37 PM, Simon Clubley wrote:
> On 2023-05-10, Arne Vajhøj <arne at vajhoej.dk> wrote:
>> On 5/10/2023 9:23 AM, Johnny Billquist wrote:
>>> On 2023-05-10 14:23, Simon Clubley wrote:
>>>> There's no way that x86-64 VMS, at this point in its lifecycle, can
>>>> meet those criteria, although hopefully that will change rapidly in
>>>> the not too distant future.
>>>>
>>>> For one thing, x86-64 VMS is still built using non-optimised compilers.
>>>>
>>>> Any person with any experience elsewhere of the implications of that,
>>>> should be asking how many bugs and other issues will emerge once VMS is
>>>> built using optimised compilers ?
>>>
>>> This is utter nonsense. Optimizing code don't suddenly create new bugs.
>>> Unless there are bugs in the toolchain, non-optimized code and optimized
>>> code will produce the same results, but the amount of time and memory
>>> required might differ. Or else the bugs are already there in the
>>> unoptimized code.
>>
>> Correct code will produce the same result non-optimized and optimized.
> 
> Unless the optimiser has a bug in it. :-)

Johnny's premise was "Unless there are bugs in the toolchain".

Per my understanding the optimization happen in generic LLVM code
aka well tested code so the risk of an optimizer bug should be small.

>> In-correct code can produce different results.
> 
> Yes. _Apparently_ working code can suddenly become non-working code when
> an optimiser is turned on for the first time or (as you point out in
> another reply) when the optimiser is changed.

It can happen.

Arne