From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-516166-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 45680 invoked by alias); 18 Dec 2019 02:50:56 -0000
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
Received: (qmail 45672 invoked by uid 89); 18 Dec 2019 02:50:56 -0000
Authentication-Results: sourceware.org; auth=none
X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.1 spammy=HX-Languages-Length:1123, H*RU:209.85.222.67, HX-Spam-Relays-External:209.85.222.67, H*f:sk:fzQ@mai
X-HELO: mail-ua1-f67.google.com
Received: from mail-ua1-f67.google.com (HELO mail-ua1-f67.google.com) (209.85.222.67) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 18 Dec 2019 02:50:55 +0000
Received: by mail-ua1-f67.google.com with SMTP id l6so97863uap.13        for <gcc-patches@gcc.gnu.org>; Tue, 17 Dec 2019 18:50:55 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;        d=gmail.com; s=20161025;        h=mime-version:references:in-reply-to:from:date:message-id:subject:to         :cc;        bh=AH02l9H6JZY5j5xpLg43znD1Sjg+bdz3Ir801ah46VM=;        b=jLhwUYCr6c/VzobOu76Oz3UbUIw/Aj89Ah2cbTa5Mw3Jwgf45Bv6UeqjyfHn2yAeTO         4OvwITkbJwVDfddpbDrNmwbnPNlCKK7Ya47LS1AC9+EPx/Nc5kafyIEZwrntfyMM2gfy         L3JimtnzY88Ixre8oqRySbA0vAIN076XqHfFO8JXej0amg4LybTaOgWPZuXj+cr1NSTb         yxu/KiXkdrb/L43KvvgU/D0nA64C9r74QevQb0R7W7vRDcXJbBa6X5m/JsmQ1zJo2ybO         frhUojgpTxQBU8g/UvSrAMXKD4TmKPor9XdvcCfkjSmcZZKjq0L1tlLvYoZBGE0AyDxL         4XMg==
MIME-Version: 1.0
References: <CAMZc-bzZQtasc6N_vBvyd1J2wOZ+JJEoFm6b-bDRir5EY-=fzQ@mail.gmail.com>
In-Reply-To: <CAMZc-bzZQtasc6N_vBvyd1J2wOZ+JJEoFm6b-bDRir5EY-=fzQ@mail.gmail.com>
From: Andrew Pinski <pinskia@gmail.com>
Date: Wed, 18 Dec 2019 02:57:00 -0000
Message-ID: <CA+=Sn1=omWKLkC_K96QapK06QG8v+feXcRNi0hsr71_rbjDhrA@mail.gmail.com>
Subject: Re: [PATCH] Fix redundant load missed by fre [tree-optimization 92980]
To: Hongtao Liu <crazylht@gmail.com>
Cc: Richard Biener <richard.guenther@gmail.com>, GCC Patches <gcc-patches@gcc.gnu.org>, 	"H. J. Lu" <hjl.tools@gmail.com>, wwwhhhyyy333@gmail.com
Content-Type: text/plain; charset="UTF-8"
X-IsSubscribed: yes
X-SW-Source: 2019-12/txt/msg01245.txt.bz2

On Tue, Dec 17, 2019 at 6:33 PM Hongtao Liu <crazylht@gmail.com> wrote:
>
> Hi:
>   This patch is to simplify A * C + (-D) -> (A - D/C) * C when C is a
> power of 2 and D mod C == 0.
>   bootstrap and make check is ok.

I don't see why D has to be negative here.


>TREE_CODE (TREE_TYPE (@0)) == INTEGER_TYPE
+     && TYPE_UNSIGNED (TREE_TYPE (@0))

This is the wrong check here.
Use INTEGRAL_TYPE_P .

>+ (plus (mult @0 integer_pow2p@1) INTEGER_CST@2)

 You might want a :s here for the mult and/or plus.

unsigned HOST_WIDE_INT d = tree_to_uhwi (@2);
...
Maybe use wide_int math instead of HOST_WIDE_INT here, then you don't
need the tree_fits_uhwi_p check.

Add a testcase should tests the pattern directly rather than indirectly.

Also we are in stage 3 which means bug fixes only so this might/should
wait until stage 1.

Thanks,
Andrew Pinski

>
> changelog
> gcc/
>         * gcc/match.pd (A * C + (-D) = (A - D/C) * C. when C is a
>         power of 2 and D mod C == 0): Add new simplification.
>
> gcc/testsuite
>         * gcc.dg/pr92980.c: New test.
>
> --
> BR,
> Hongtao