From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7554 invoked by alias); 13 Nov 2014 15:12:41 -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 7485 invoked by uid 48); 13 Nov 2014 15:12:31 -0000 From: "renlin.li at arm dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/63762] [ARM]GCC generates UNPREDICTABLE STR with Rn = Rt when hard-float abi is used Date: Thu, 13 Nov 2014 15:12:00 -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: 4.9.0 X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: renlin.li at arm dot com X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: renlin.li at arm dot com 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: 2014-11/txt/msg01124.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63762 --- Comment #2 from Renlin Li --- r278 is derived from r224 which is a VFP_LO_REGS. find_cost_and_classes assigns r278's class as GENERAL_REGS, and assign it hard_reg 2. Another new pseudo register r290 is created from r278, and assigned to the same hard_register and register class (GENERAL_REGS). The pref_class of r290 is derived from its original reg (r224), which is VFP_LO_REGS In lra during the hard register assignment process, conflict is checked for r302 which is a GENERAL_REGS. r290 is not considered, because of different register classes(reg_pref[290].pref_class == VFP_LO_REGS ). Hard register number 2 is chosen in this case.