From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-413291-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 32438 invoked by alias); 25 Jan 2013 22:48:16 -0000
Received: (qmail 32270 invoked by uid 48); 25 Jan 2013 22:47:41 -0000
From: "akobets at mail dot ru" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/56114] New: x86_64-linux-gnu-gcc generate wrong asm instruction MOVABS for intel syntax
Date: Fri, 25 Jan 2013 22:48:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: akobets at mail dot ru
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-56114-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2013-01/txt/msg02410.txt.bz2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56114

             Bug #: 56114
           Summary: x86_64-linux-gnu-gcc generate wrong asm instruction
                    MOVABS for intel syntax
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: akobets@mail.ru


For example file l.c

long foo2 (void)
{
  return *(volatile long*)0xFEE00000;
}

x86_64-linux-gnu-gcc -c -save-temps l.c -O2 -masm=intel
cat l.s
    .file    "l.c"
    .intel_syntax noprefix
    .text
    .p2align 4,,15
    .globl    foo2
    .type    foo2, @function
foo2:
.LFB0:
    .cfi_startproc
    movabs    rax, 4276092928
    ret

This is erroneous instruction, because movabs rax, 4276092928 loads immediate
data. This code must be
movabs    rax, [4276092928]
with square brackets.

When we try to read 32-bit data from memory, then we get error message
long foo2 (void)
{
  return *(volatile int*)0xFEE00000;
}
x86_64-linux-gnu-gcc -c -save-temps l.c -O2 -masm=intel
cat l.s
    .file    "l.c"
    .intel_syntax noprefix
    .text
    .p2align 4,,15
    .globl    foo2
    .type    foo2, @function
foo2:
.LFB0:
    .cfi_startproc
    movabs    eax, 4276092928
    cdqe
    ret

Because movabs allows load 64-bit only immediate data. Here is GCC loose square
brackets.