[SystemSafety] Accuracy of COVID modeling code

Derek M Jones derek at knosof.co.uk
Sat May 9 18:41:54 CEST 2020


> I haven't seen a language specification that rules out any form of
> optimisation that involves rearranging code or using mathematically
> equivalent operations. Please post a link to the sections of those that
> you have seen that make that clear.

Section of the C Standard,

or sentence 189: https://c0x.coding-guidelines.com/
"In the abstract machine, all expressions are evaluated as specified by the semantics."

There as an as-if rule that allows implementations to do what they
like (e.g., turn an integer multiple by two into a shift), as long as
the behavior is the same.

Derek M. Jones           Evidence-based software engineering
tel: +44 (0)1252 520667  blog:shape-of-code.coding-guidelines.com

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