From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 782963858424; Fri, 26 Nov 2021 05:08:40 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 782963858424
From: "wilson at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/103271] ICE in assign_stack_temp_for_type with
 -ftrivial-auto-var-init=pattern and VLAs and -mno-strict-align on riscv64
Date: Fri, 26 Nov 2021 05:08:40 +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: 12.0
X-Bugzilla-Keywords: ice-on-valid-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: wilson 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: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-103271-4-DwWlGHQF6A@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-103271-4@http.gcc.gnu.org/bugzilla/>
References: <bug-103271-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Fri, 26 Nov 2021 05:08:40 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D103271

Jim Wilson <wilson at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |wilson at gcc dot gnu.org

--- Comment #5 from Jim Wilson <wilson at gcc dot gnu.org> ---
SiFive doesn't support -mno-strict-align so I've never tested it.  I doubt =
that
it works correctly, i.e. I doubt that it optimizes as intended.  I've menti=
oned
this to other RVI members, but there hasn't been anyone other than SiFive
actively working on upstream gcc so I don't think anyone ever looked at it.=
  It
shouldn't give an ICE though.

Looking at this, it appears to be another "if only we had a movti pattern"
issue.

In expand_DEFERRED_INIT in internal-fn.c, in the reg_lhs =3D=3D TRUE case, =
there is
a test
          && have_insn_for (SET, var_mode))
which fails because var_mode is TImode and we don't have a movti pattern.  =
The
code calls build_zero_cst which returns a constructor with an array type.  =
We
then call expand_assignment which gets confused as it doesn't know the size=
 of
the array it is copying.

However, if we had a movti pattern, then the code computes the size of the
array, and creates a VIEW_CONVERT_EXPR to document the array size before
calling expand_assignment.  So it looks like it would work if we had a movti
pattern.

I verified that adding a dummy movti pattern makes the ICE go away.=