From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-493730-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 11002 invoked by alias); 30 Jul 2015 07:48:21 -0000
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
Received: (qmail 8226 invoked by uid 48); 30 Jul 2015 07:48:09 -0000
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/66917] [4.9/5/6 regression] ARM: NEON: memcpy compiles to vst1 with incorrect alignment due to SRA
Date: Thu, 30 Jul 2015 07:48:00 -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: 4.9.3
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: major
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution:
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 4.9.4
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields:
Message-ID: <bug-66917-4-Qjp4HXNteI@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-66917-4@http.gcc.gnu.org/bugzilla/>
References: <bug-66917-4@http.gcc.gnu.org/bugzilla/>
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: 2015-07/txt/msg02620.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66917

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
Suggested fix:

Index: gcc/config/arm/arm.c
===================================================================
--- gcc/config/arm/arm.c        (revision 226348)
+++ gcc/config/arm/arm.c        (working copy)
@@ -27217,7 +27217,8 @@ arm_builtin_support_vector_misalignment
 {
   if (TARGET_NEON && !BYTES_BIG_ENDIAN && unaligned_access)
     {
-      HOST_WIDE_INT align = TYPE_ALIGN_UNIT (type);
+      HOST_WIDE_INT align
+       = GET_MODE_ALIGNMENT (TYPE_MODE (type)) / BITS_PER_UNIT;

       if (is_packed)
         return align == 1;

which produces

        push    {r4}
        add     r3, r0, #8
        add     r4, r1, #8
        vld1.64 {d17}, [r1]
        vld1.64 {d16}, [r4]
        ldr     r4, [sp], #4
        vld1.64 {d19}, [r3]
        veor    d16, d16, d19
        vld1.64 {d18}, [r0]
        veor    d17, d17, d18
        vst1.64 {d17}, [r2]!
        vst1.64 {d16}, [r2]
        bx      lr