From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20477 invoked by alias); 15 Oct 2013 00:31:46 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 20465 invoked by uid 89); 15 Oct 2013 00:31:45 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=0.1 required=5.0 tests=BAYES_50,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-we0-f174.google.com Received: from mail-we0-f174.google.com (HELO mail-we0-f174.google.com) (74.125.82.174) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Tue, 15 Oct 2013 00:31:45 +0000 Received: by mail-we0-f174.google.com with SMTP id u56so7713496wes.19 for ; Mon, 14 Oct 2013 17:31:41 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.180.91.16 with SMTP id ca16mr16578289wib.57.1381797101850; Mon, 14 Oct 2013 17:31:41 -0700 (PDT) Received: by 10.227.22.9 with HTTP; Mon, 14 Oct 2013 17:31:41 -0700 (PDT) Date: Tue, 15 Oct 2013 00:31:00 -0000 Message-ID: Subject: programming language that does not inhibit further optimization by gcc From: Albert Abramson To: gcc@gcc.gnu.org Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable X-SW-Source: 2013-10/txt/msg00146.txt.bz2 I have been looking everywhere online and talking to other coders at every opportunity about this, but cannot find a complete answer. Different languages have different obstacles to complete optimization. Software developers often have to drop down into non-portable Assembly because they can't get the performance or small size of hand-optimized Assembly for their particular platform. The C language has the alias issue that limits the hoisting of loads. Unless the programmer specifies that two arrays will never overlap using the 'restrict' keyword, the compiler may not be able to handle operations on arrays efficiently because of the unlikely event that the arrays could overlap. Most/all languages also demand the appearance of serialization of instructions and memory operations, as well as extreme correctness in even the most unlikely circumstances, even where the programmer may not need them. Is there a language out there (similar to Fortran or a dialect of C) that doesn't inhibit the compiler from taking advantage of every optimization possible? Is there some way to provide a C/C++ compiler with extra information about variables and programs so that it can maximize performance or minimize size? For example: int age =3D 21; //[0, 150) setting maximum limits, compiler could use b= yte int int outsideTemp =3D 20; //[-273, 80] float ERA =3D 297; //[0, 1000, 3] [min, max, digits of accuracy needed] Better yet, allow some easier way of spawning multiple threads without have to learn all of the Boost libraries, OpenCL, or OpenGL. In other words, is there yet a language that is designed only for performance that places no limits on compiler optimizations? Is there a language that allows the compiler to pack struct variables in tighter by reorganizing those values, etc? If not, is it possible to put together some dialect of C/C++ that replaces Assembly outright? --=20 Max Abramson =93In the end, more than freedom, they wanted security. They wanted a comfortable life, and they lost it all =96 security, comfort, and freedom. When the Athenians finally wanted not to give to society but for society to give to them, when the freedom they wished for most was freedom from responsibility, then Athens ceased to be free and was never free again.=94 --Sir Edward Gibbon