From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.devel Subject: Re: Shrinking the C core Date: Mon, 28 Aug 2023 06:41:28 +0200 Message-ID: <87jztfrd6v.fsf@dataswamp.org> References: <20230809094655.793FC18A4654@snark.thyrsus.com> <87edk3gbh3.fsf@dataswamp.org> <87jztvnuyb.fsf@localhost> <875y5bdutt.fsf@dataswamp.org> <87y1i6e1uh.fsf@localhost> <874jkub40o.fsf@dataswamp.org> <87jztqdw2l.fsf@localhost> <87msym9i4r.fsf@dataswamp.org> <877cpp914t.fsf@localhost> <83fs4dwwdo.fsf@gnu.org> <874jkt90a5.fsf@localhost> <87y1i57jqi.fsf@localhost> <87pm3h7h8k.fsf@localhost> <87h6ot7cf3.fsf@localhost> <87edjx7c0b.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31167"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: emacs-devel@gnu.org Cancel-Lock: sha1:rEImM+iT0FBp/MwiPUwfInF6Vec= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Mon Aug 28 12:56:20 2023 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qaZuu-0007iR-TI for ged-emacs-devel@m.gmane-mx.org; Mon, 28 Aug 2023 12:56:20 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qaZsn-0007lV-02; Mon, 28 Aug 2023 06:54:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qaU4Q-00016y-5C for emacs-devel@gnu.org; Mon, 28 Aug 2023 00:41:46 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qaU4N-0007hK-Rv for emacs-devel@gnu.org; Mon, 28 Aug 2023 00:41:45 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1qaU4M-0009tt-0r for emacs-devel@gnu.org; Mon, 28 Aug 2023 06:41:42 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: emacs-devel@gnu.org Mail-Copies-To: never Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Mon, 28 Aug 2023 06:54:06 -0400 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:309421 Archived-At: Ihor Radchenko wrote: >> The only problem (AFAIU) is that GCC JIT cannot reach >> inside subr level, so all these information does not >> benefit Emacs functions implemented in C. > > If I am right here, it might actually be worth it to rewrite > some of the subroutines into Elisp. For example > rounding_driver (called by `floor') code is full of runtime > type checks: > > CHECK_NUMBER (n); > if (NILP (d)) > ... > CHECK_NUMBER (d); > ... > if (FIXNUMP (d)) > if (XFIXNUM (d) == 0) > ... > if (FIXNUMP (n)) > ... > else if (FLOATP (d)) > if (XFLOAT_DATA (d) == 0) > int nscale = FLOATP (n) ? double_integer_scale (XFLOAT_DATA (n)) : 0; > .. > > During native compilation, if type information and n and > d is available, GCC might have a chance to cut a number of > branches away from the above code. Does this indicate a tendency where one can foresee a future where Elisp is as fast as C to the point C could be dropped completely? Even today we can run singular Elisp programs. But not without Emacs and its Lisp interpreter, which is written in C. Still, I wonder if those typechecks in C really slow things down to the point it matters. Maybe for really huge number-crunching computations? -- underground experts united https://dataswamp.org/~incal