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Re: g++ and aliasing bools
Gabriel Dos Reis wrote:
>firstname.lastname@example.org (Richard Kenner) writes:
>| I am very much against the idea of defining a change to be "correct" if
>| it doesn't cause any regression test failures. You have to be able to make
>| an argument that a change is correct independently and the regression tests
>| serve as a debugger of (among other things) that proof.
>I completely agree with Kenner and Mark. Given, current ABIs
>supported by g++, aliasing detection is a very subtle issue and we
>should resist from the temptation of not proving that our algorithms
>are correct; simply because correctness should come first, speed later.
>That doesn't mean I'm against any effort to improve alias analysis in
>g++, I'm simply against a change which doesn't consider correctness as
In this connection I would like to clearly state that indeed I agree
with all of you. By the way, I'm doing proofs myself daily in my
research work and I *understand* the power of abstract reasoning!
My sympathy with Dan's message was due to the fact that in the last
months I got the impression that C++-alias analysis may be really
crucial in order to effectively optimize some codes whereas it looks
like, for some reason nobody among the knowledgeable people is actively
working on it... I took Dan's words as a spur for the C++ developers to
start working again on that without being scared by the first technical