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Re: [std-proposals] Every variable is volatile, everything is laundered, no optimisation

From: Alejandro Colomar <alx.manpages_at_[hidden]>
Date: Mon, 28 Aug 2023 14:44:57 +0200
Hi Hyman,

On 2023-08-28 09:12, Hyman Rosen via Std-Proposals wrote:
> I'm the "optimizationist" guy.

[... blaming the ISO C++ dialect ...]

> Order of evaluation should be strictly left-to-right for all expressions.
> The whole notion that executing undefined behavior makes the behavior of
> the entire program unspecified, and therefore allows compilers to pretend
> that undefined behavior is never executed, is completely wrongheaded. At
> the very least, it should be required that all side effects that would have
> been encountered by the abstract machine ahead of the undefined behavior
> must occur. The best thing would be to incorporate Ada's notion of "bounded
> errors", where many things now specified as undefined behavior would become
> defined to produce a range of possible outcomes, with the program
> continuing to execute in most cases.

This dialect of C++ that you like does exist. It is non-standard, because
it seems not all programmers agree with it (I don't like this dialect, for
example). But if you want to talk that dialect, nothing is forcing you to
talk ISO C++.

$ g++ -O0 -fno-strict-overflow -fwrapv -fno-trapv -fno-strict-aliasing

If your compiler doesn't support that dialect, then change your compiler.
You're basically asking for C++-like assembly dialect, which is a fair ask.


Received on 2023-08-28 12:45:01