From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 123873 invoked by alias); 5 Mar 2015 20:01:02 -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 123759 invoked by uid 48); 5 Mar 2015 20:00:59 -0000 From: "law at redhat dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/64317] [5 Regression] Ineffective allocation of PIC base register Date: Thu, 05 Mar 2015 20:01:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: rtl-optimization X-Bugzilla-Version: 5.0 X-Bugzilla-Keywords: missed-optimization, ra X-Bugzilla-Severity: normal X-Bugzilla-Who: law at redhat dot com X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 5.0 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: 2015-03/txt/msg00656.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64317 --- Comment #22 from Jeffrey A. Law --- Yes, absolutely, we have to compensate for the case where B clobbers something useful, undoing transformations, etc. It may not be reasonably feasible within the current structure of LRA. I'm getting pretty close on getting postreload-gcse.c to handle this. Most of the complexity has been in untangling the bits from gcse.c that I want to re-use. There's obviously cleanup still to do and some instrumentation/analysis of the generated code on a wider codebase, but it looks promising.