From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 132CAC4338F for ; Mon, 16 Aug 2021 15:17:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD93260E97 for ; Mon, 16 Aug 2021 15:17:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232908AbhHPPSU (ORCPT ); Mon, 16 Aug 2021 11:18:20 -0400 Received: from smtp-out2.suse.de ([195.135.220.29]:37872 "EHLO smtp-out2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232237AbhHPPST (ORCPT ); Mon, 16 Aug 2021 11:18:19 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id D6E6C1FED8; Mon, 16 Aug 2021 15:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1629127066; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=znmd6DssRyB2gfAtJKubIBtDRd+udlprmsCrGGY3Om0=; b=cQl4TLBb0Tr4QCzIVVearQCOzWbiHhxEk3ZGitlq6qYpKHaM/w4GjDWJymvVO5oKVwHQw6 wZ3hHwmJ6tOEoFACCFrkQWnF18oFWKp8kUSVD2dmrGsd0Rs/cMlcYjWjYRIshYgtQvEnPz 8qq6KdYQcWDTtY65pPBvzURAQYVlVQI= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1629127066; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=znmd6DssRyB2gfAtJKubIBtDRd+udlprmsCrGGY3Om0=; b=USzbCISfA02HQ5tqSQm8ikO4/GfZngomVPuPTJF4dKm91RxrJ3oMGMl6REEMR0fp3eLTw8 pUfNxBnZwIa0kIDw== Received: from ds.suse.cz (ds.suse.cz [10.100.12.205]) by relay2.suse.de (Postfix) with ESMTP id BFA7AA3B87; Mon, 16 Aug 2021 15:17:46 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 07B8FDA72C; Mon, 16 Aug 2021 17:14:50 +0200 (CEST) Date: Mon, 16 Aug 2021 17:14:50 +0200 From: David Sterba To: Nathan Chancellor Cc: Andrew Morton , Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, terrelln@fb.com Subject: Re: [PATCH] lib/zstd: Fix bitwise vs logical operators Message-ID: <20210816151450.GF5047@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Nathan Chancellor , Andrew Morton , Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, terrelln@fb.com References: <20210815004154.1781834-1-nathan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210815004154.1781834-1-nathan@kernel.org> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org You should CC Nick Terell for ZSTD patches, added. On Sat, Aug 14, 2021 at 05:41:54PM -0700, Nathan Chancellor wrote: > clang warns several times along the lines of: > > lib/zstd/compress.c:1043:7: warning: bitwise and of boolean expressions; did you mean logical and? [-Wbool-operation-and] > if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > && > > Bitwise ANDs do not short circuit, meaning that the ZSTD_read32 calls > will be evaluated even if the first condition is not true. This is not > always a problem but it is not a standard way to do conditionals so > replace the bitwise ANDs with logical ones to fix the warning and make > the code clearer. > > Signed-off-by: Nathan Chancellor > --- > lib/zstd/compress.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/lib/zstd/compress.c b/lib/zstd/compress.c > index b080264ed3ad..0e515d1d4237 100644 > --- a/lib/zstd/compress.c > +++ b/lib/zstd/compress.c > @@ -1040,7 +1040,7 @@ void ZSTD_compressBlock_fast_generic(ZSTD_CCtx *cctx, const void *src, size_t sr > const BYTE *match = base + matchIndex; > hashTable[h] = curr; /* update hash table */ > > - if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { > + if ((offset_1 > 0) && (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { > mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4; > ip++; > ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH); > @@ -1072,7 +1072,7 @@ void ZSTD_compressBlock_fast_generic(ZSTD_CCtx *cctx, const void *src, size_t sr > hashTable[ZSTD_hashPtr(base + curr + 2, hBits, mls)] = curr + 2; /* here because curr+2 could be > iend-8 */ > hashTable[ZSTD_hashPtr(ip - 2, hBits, mls)] = (U32)(ip - 2 - base); > /* check immediate repcode */ > - while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > + while ((ip <= ilimit) && ((offset_2 > 0) && (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > /* store sequence */ > size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4; > { > @@ -1291,7 +1291,7 @@ void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx *cctx, const void *src, siz > const BYTE *match = base + matchIndexS; > hashLong[h2] = hashSmall[h] = curr; /* update hash tables */ > > - if ((offset_1 > 0) & (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { /* note : by construction, offset_1 <= curr */ > + if ((offset_1 > 0) && (ZSTD_read32(ip + 1 - offset_1) == ZSTD_read32(ip + 1))) { /* note : by construction, offset_1 <= curr */ > mLength = ZSTD_count(ip + 1 + 4, ip + 1 + 4 - offset_1, iend) + 4; > ip++; > ZSTD_storeSeq(seqStorePtr, ip - anchor, anchor, 0, mLength - MINMATCH); > @@ -1350,7 +1350,7 @@ void ZSTD_compressBlock_doubleFast_generic(ZSTD_CCtx *cctx, const void *src, siz > hashLong[ZSTD_hashPtr(ip - 2, hBitsL, 8)] = hashSmall[ZSTD_hashPtr(ip - 2, hBitsS, mls)] = (U32)(ip - 2 - base); > > /* check immediate repcode */ > - while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > + while ((ip <= ilimit) && ((offset_2 > 0) && (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > /* store sequence */ > size_t const rLength = ZSTD_count(ip + 4, ip + 4 - offset_2, iend) + 4; > { > @@ -1929,7 +1929,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t src > const BYTE *start = ip + 1; > > /* check repCode */ > - if ((offset_1 > 0) & (ZSTD_read32(ip + 1) == ZSTD_read32(ip + 1 - offset_1))) { > + if ((offset_1 > 0) && (ZSTD_read32(ip + 1) == ZSTD_read32(ip + 1 - offset_1))) { > /* repcode : we take it */ > matchLength = ZSTD_count(ip + 1 + EQUAL_READ32, ip + 1 + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32; > if (depth == 0) > @@ -1953,7 +1953,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t src > if (depth >= 1) > while (ip < ilimit) { > ip++; > - if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) { > + if ((offset) && ((offset_1 > 0) && (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) { > size_t const mlRep = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32; > int const gain2 = (int)(mlRep * 3); > int const gain1 = (int)(matchLength * 3 - ZSTD_highbit32((U32)offset + 1) + 1); > @@ -1974,7 +1974,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t src > /* let's find an even better one */ > if ((depth == 2) && (ip < ilimit)) { > ip++; > - if ((offset) && ((offset_1 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) { > + if ((offset) && ((offset_1 > 0) && (ZSTD_read32(ip) == ZSTD_read32(ip - offset_1)))) { > size_t const ml2 = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_1, iend) + EQUAL_READ32; > int const gain2 = (int)(ml2 * 4); > int const gain1 = (int)(matchLength * 4 - ZSTD_highbit32((U32)offset + 1) + 1); > @@ -2021,7 +2021,7 @@ void ZSTD_compressBlock_lazy_generic(ZSTD_CCtx *ctx, const void *src, size_t src > } > > /* check immediate repcode */ > - while ((ip <= ilimit) && ((offset_2 > 0) & (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > + while ((ip <= ilimit) && ((offset_2 > 0) && (ZSTD_read32(ip) == ZSTD_read32(ip - offset_2)))) { > /* store sequence */ > matchLength = ZSTD_count(ip + EQUAL_READ32, ip + EQUAL_READ32 - offset_2, iend) + EQUAL_READ32; > offset = offset_2; > > base-commit: ba31f97d43be41ca99ab72a6131d7c226306865f > -- > 2.33.0.rc2