From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20518 invoked by alias); 15 Jun 2013 17:01:04 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 20448 invoked by uid 55); 15 Jun 2013 17:00:54 -0000 From: "sgunderson at bigfoot dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/57623] BEXTR intrinsic has memory operands switched around (fails to compile code) Date: Sat, 15 Jun 2013 17:01:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 4.8.1 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: sgunderson at bigfoot dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2013-06/txt/msg00803.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57623 --- Comment #2 from sgunderson at bigfoot dot com --- On Sat, Jun 15, 2013 at 04:33:14PM +0000, jakub at gcc dot gnu.org wrote: > The fix for the compiler is easy, but at least the AVX2 spec documents that > _bextr_u{32,64} intrinsics actually take 3 arguments (source, start and > length), > with the latter two always unsigned int, while our intrinsic has only two > arguments (where the latter is expected to be (start & 255) | (length << 8)). > Not sure if we want to change this, and if so, just for 4.9+, or also for > 4.8.2+ and 4.7.4+? If you decide to change it, at least consider keeping the old version around; for instance, the start/length combination could come from a table. In general, if you actually have to do shifting and stuff to create this operand, the gain of the instruction is already lost. /* Steinar */