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 9D0333858D32; Mon, 29 May 2023 06:14:46 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9D0333858D32
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1685340886;
	bh=JZvQ6UFvqzaKTexVNE+juwGt37SjRWzO9rCoQsE5PeU=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=BCx9WTzU5KjAarUqs/VIiZ4ealiRqXYyXTt/AIJn0HVyFUI9rjeEzwkFuFEKrq+qJ
	 dgUS3vhPJYXfbI7S7vYQ9pTS3Ro8GMDDguDnLlDU2c3fT5h9OLEPW/4dJkWaAQ87xT
	 YWvVRE1eRmOnhxW9HRjWi0XF+pbHvKqcY9ifjhCM=
From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug middle-end/110018] Missing vectorizable_conversion(unsigned
 char -> double) for BB vectorizer
Date: Mon, 29 May 2023 06:14:46 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: middle-end
X-Bugzilla-Version: 13.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: crazylht at gmail dot com
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: 
Message-ID: <bug-110018-4-Nb4FTNCr7e@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-110018-4@http.gcc.gnu.org/bugzilla/>
References: <bug-110018-4@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=3D110018

--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
Even we have direct optab for unsigned char to long long, BB vectorizer fai=
ler
to optimize

void
foo1 (long long* __restrict a, unsigned char* b)
{
    a[0] =3D b[0];
    a[1] =3D b[1];
    a[2] =3D b[2];
    a[3] =3D b[3];
    a[4] =3D b[4];
    a[5] =3D b[5];
    a[6] =3D b[6];
    a[7] =3D b[7];
}

since we have vectype_out as V4DImode, but vectype_in as V8QImode as *vecty=
pe =3D
SLP_TREE_VECTYPE (child);

If manually change the testcase to

void
foo1 (long long* __restrict a, unsigned char* b)
{
    a[0] =3D b[0];
    a[1] =3D b[1];
    a[2] =3D b[2];
    a[3] =3D b[3];
}

Then BB vectorizer can do vectorization, but still failed for

void
foo1 (double* __restrict a, unsigned char* b)
{
    a[0] =3D b[0];
    a[1] =3D b[1];
    a[2] =3D b[2];
    a[3] =3D b[3];
}

So it looks there're 2 separate issue
1. As mentioned in the PR, we can use intermediate type for vectorizable
unsigned char to double.
2. There's mismatch between vectype_out and vectype_in as SLP_TREE_VECTYPE
(child);=