From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by sourceware.org (Postfix) with ESMTPS id BA6993865488 for ; Tue, 11 May 2021 08:20:48 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org BA6993865488 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=rguenther@suse.de X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A9153AFC2; Tue, 11 May 2021 08:20:47 +0000 (UTC) Date: Tue, 11 May 2021 10:20:47 +0200 (CEST) From: Richard Biener To: Jakub Jelinek cc: gcc-patches@gcc.gnu.org, Jonathan Wakely Subject: Re: [PATCH] match.pd: Optimize (x & y) == x into (x & ~y) == 0 [PR94589] In-Reply-To: <20210511073405.GE1179226@tucnak> Message-ID: References: <20210504074413.GI1179226@tucnak> <20210505165227.GT1179226@tucnak> <20210506102230.GY1179226@tucnak> <4139aa5f-e3c3-c1ce-7fc3-a1e41a4d4c20@hippo.saclay.inria.fr> <20210511073405.GE1179226@tucnak> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 X-Spam-Status: No, score=-5.4 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 May 2021 08:20:51 -0000 On Tue, 11 May 2021, Jakub Jelinek wrote: > On Thu, May 06, 2021 at 09:42:41PM +0200, Marc Glisse wrote: > > We can probably do it in 2 steps, first something like > > > > (for cmp (eq ne) > > (simplify > > (cmp (bit_and:c @0 @1) @0) > > (cmp (@0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); }))) > > > > to get rid of the double use, and then simplify X&C==0 to X<=~C if C is a > > mask 111...000 (I thought we already had a function to detect such masks, or > > the 000...111, but I can't find them anymore). > > Ok, here is the first step then. > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > Or should it have cmp:c too given that == and != are commutative too? I think so. OK with that change. Richard. > 2021-05-11 Jakub Jelinek > Marc Glisse > > PR tree-optimization/94589 > * match.pd ((X & Y) == Y -> (X & ~Y) == 0, > (X | Y) == Y -> (X & ~Y) == 0): New GIMPLE simplifications. > > * gcc.dg/tree-ssa/pr94589-1.c: New test. > > --- gcc/match.pd.jj 2021-04-27 14:46:56.583716888 +0200 > +++ gcc/match.pd 2021-05-10 22:31:49.726870421 +0200 > @@ -4764,6 +4764,18 @@ (define_operator_list COND_TERNARY > (cmp:c (bit_xor:c @0 @1) @0) > (cmp @1 { build_zero_cst (TREE_TYPE (@1)); })) > > +#if GIMPLE > + /* (X & Y) == X becomes (X & ~Y) == 0. */ > + (simplify > + (cmp (bit_and:c @0 @1) @0) > + (cmp (bit_and @0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); })) > + > + /* (X | Y) == Y becomes (X & ~Y) == 0. */ > + (simplify > + (cmp (bit_ior:c @0 @1) @1) > + (cmp (bit_and @0 (bit_not! @1)) { build_zero_cst (TREE_TYPE (@0)); })) > +#endif > + > /* (X ^ C1) op C2 can be rewritten as X op (C1 ^ C2). */ > (simplify > (cmp (convert?@3 (bit_xor @0 INTEGER_CST@1)) INTEGER_CST@2) > --- gcc/testsuite/gcc.dg/tree-ssa/pr94589-1.c.jj 2021-05-10 22:36:10.574130179 +0200 > +++ gcc/testsuite/gcc.dg/tree-ssa/pr94589-1.c 2021-05-10 22:36:17.789054362 +0200 > @@ -0,0 +1,21 @@ > +/* PR tree-optimization/94589 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2 -fdump-tree-optimized" } */ > + > +int > +foo (int x) > +{ > + return (x & 23) == x; > +/* { dg-final { scan-tree-dump " & -24;" "optimized" } } */ > +/* { dg-final { scan-tree-dump-not " & 23;" "optimized" } } */ > +/* { dg-final { scan-tree-dump " == 0" "optimized" } } */ > +} > + > +int > +bar (int x) > +{ > + return (x | 137) != 137; > +/* { dg-final { scan-tree-dump " & -138;" "optimized" } } */ > +/* { dg-final { scan-tree-dump-not " \\| 137;" "optimized" } } */ > +/* { dg-final { scan-tree-dump " != 0" "optimized" } } */ > +} > > > Jakub > > -- Richard Biener SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)