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 D52BB3857347; Wed, 19 Oct 2022 09:08:51 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D52BB3857347
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1666170531;
	bh=QVPpVQ5AlWXd+6ujrJ9q5+LNYoFsudUjTP0infgAPjw=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=SoQN8ysDItyrGM7R65mG5vINyNRC1vaw/UYaBy1s+x2nqEXmk63N0GhiEWXxrE8Zh
	 JdPxeJ0yTH8T6V1MZbpDT8rmFlHWyQpHud0pYNWRKQoZ97UV/FIewVCnFXGMy30E5p
	 Hagq+1wstXsOCAgxg19+y0Id1Db8w1TtCJZUTbW0=
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/89224] [10/11/12/13 Regression] subscript of const vector
 has the wrong type
Date: Wed, 19 Oct 2022 09:08:50 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 8.2.0
X-Bugzilla-Keywords: accepts-invalid, wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 10.5
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc priority
Message-ID: <bug-89224-4-OKazuJ9NtZ@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-89224-4@http.gcc.gnu.org/bugzilla/>
References: <bug-89224-4@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
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D89224

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
           Priority|P3                          |P2

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is likely that lvalue_kind of

 <parm_decl 0x7ffff7ff3180 x
    type <vector_type 0x7ffff6684bd0 __Int8x8_t
        type <integer_type 0x7ffff653b348 unsigned char public unsigned QI
            size <integer_cst 0x7ffff653d090 constant 8>
            unit-size <integer_cst 0x7ffff653d0a8 constant 1>
            align:8 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff653b348 precision:8 min <integer_cst 0x7ffff653d0c0 0> max <integer_=
cst
0x7ffff653d060 255>>
        readonly unsigned V16QI
        size <integer_cst 0x7ffff6517fd8 constant 128>
        unit-size <integer_cst 0x7ffff653d000 constant 16>
        align:128 warn_if_not_align:0 symtab:0 alias-set -1 canonical-type
0x7ffff6684c78 nunits:16>
    readonly used unsigned V16QI t.ii:7:25 size <integer_cst 0x7ffff6517fd8
128> unit-size <integer_cst 0x7ffff653d000 16>
    align:128 warn_if_not_align:0 context <function_decl 0x7ffff6687a00 f>
arg-type <vector_type 0x7ffff6684bd0 __Int8x8_t>>

returns clk_ordinary and thus convert_vector_to_array_for_subscript returns
false.

And that's because

214         case PARM_DECL:
215         case RESULT_DECL:
216         case PLACEHOLDER_EXPR:
217           return clk_ordinary;

we wrap the PARM_DECL in a VIEW_CONVERT_EXPR but that just gets stripped
here.

So maybe convert_vector_to_array_for_subscript is wrong in just using
lvalue_p?

I've went here just tracing cp_build_array_ref, otherwise I know nothing
about C++ or how the c-c++-common lvalue_p should behave here.=