From: Dmitry Antipov <dmantipov@yandex.ru>
To: Emacs development discussions <emacs-devel@gnu.org>
Cc: Eli Zaretskii <eliz@gnu.org>, Paul Eggert <eggert@cs.ucla.edu>,
Stefan Monnier <monnier@IRO.UMontreal.CA>
Subject: Optimize assume(...) away? (agaiin)
Date: Wed, 09 Oct 2013 20:43:17 +0400 [thread overview]
Message-ID: <525587A5.3040101@yandex.ru> (raw)
1) http://lists.gnu.org/archive/html/emacs-devel/2013-10/msg00238.html
2) http://debbugs.gnu.org/cgi/bugreport.cgi?bug=15565
3) Consider non-trivial eassert like:
eassert ((BUFFERP (it->object)
&& IT_CHARPOS (*it) == it->bidi_it.charpos
&& IT_BYTEPOS (*it) == it->bidi_it.bytepos)
|| (STRINGP (it->object)
&& IT_STRING_CHARPOS (*it) == it->bidi_it.charpos
&& IT_STRING_BYTEPOS (*it) == it->bidi_it.bytepos)
|| (CONSP (it->object) && it->method == GET_FROM_STRETCH))
a) It takes some time to check whether there are side effects here;
b) If someone change 'struct it' so IT_STRING_CHARPOS (*it)
becomes a non-trivial function with side effects, it would be
too annoying (and error-prone) to review all easserts.
Due to 1), 2) and 3) I strongly suggests to redesign eassert
to avoid any assumptions about its argument expression.
Dmitry
next reply other threads:[~2013-10-09 16:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-09 16:43 Dmitry Antipov [this message]
2013-10-09 17:21 ` Optimize assume(...) away? (agaiin) Eli Zaretskii
2013-10-09 17:55 ` Paul Eggert
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