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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
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Subject: Re: is Vax addressing sane today
Date: Tue, 10 Sep 2024 11:13:11 +0300
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On 2024-09-09 23:44, MitchAlsup1 wrote:
> On Mon, 9 Sep 2024 19:38:52 +0000, Brett wrote:

    [snip]

>> The future of programming languages is type safe with checks, you need
>> to get on that bandwagon early.
> 
> This would/will happen faster when type-safe with checks are well
> represented in benchmarks used to measure various architectural
> things, and the exceptions and checks are actually utilized showing
> performance degradation of lesser endowed architectures.


Not all the type-safe, checking languages are equal in that respect. In 
some languages, and I am thinking of Ada, the language design and the 
favored programming styles work to reduce the number of run-time checks 
required.

In the Ada case, the ability to declare array types with 
programmer-chosen index types with bounded range, such as range-bounded 
integers or enumerations, means that the compiler can avoid indexing 
checks when the (sub)type of the index is known at compile time to fit 
within the index range of the array.

It is also helpful that loop counters in Ada are also (sub)typed in the 
same way, which provides compile-time information on their range with 
respect to the index range of arrays accessed in the loop, even if the 
bounds of the range are not known at compile time.

As a result of these language features, the matching programming styles, 
and the attention paid to these issues by the compilers, the number of 
run-time checks executed by an Ada program and their effect on execution 
time are often surprisingly small.

So, to demonstrate the usefulness of HW support for checks, the 
benchmarks should use languages that require checks but do not have the 
features that let programmers reduce the number of checks by suitable 
programming styles. If Ada were used for the benchmarks, the programmers 
would have to use an abnormal, pessimal style that defeats the 
compiler's ability to elide checks.