From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18617 invoked by alias); 14 May 2010 06:31:19 -0000 Received: (qmail 18570 invoked by uid 48); 14 May 2010 06:31:08 -0000 Date: Fri, 14 May 2010 06:31:00 -0000 Message-ID: <20100514063108.18569.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug inline-asm/43998] inline assembler: can't set clobbering for input register In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "socketpair at gmail dot com" 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 X-SW-Source: 2010-05/txt/msg01476.txt.bz2 ------- Comment #11 from socketpair at gmail dot com 2010-05-14 06:31 ------- Suppose this: volatile int x; asm("something"::"a" (1)) x=1; the compiler may think that "something" do not modify eax. So next assignment may use eax ( mov eax, x ). So, "it does not make sense to have it as a clobber" is not correct. does not it ? ----------------- And the second, "Because the way the constraints are implemented inside GCC, an input constraint cannot overlap with a clobber." - It definitely the bug. -- socketpair at gmail dot com changed: What |Removed |Added ---------------------------------------------------------------------------- Status|RESOLVED |UNCONFIRMED Resolution|INVALID | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43998