From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10079 invoked by alias); 23 Feb 2017 09:02:09 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 9004 invoked by uid 89); 23 Feb 2017 09:02:08 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-23.8 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=ham version=3.3.2 spammy=HX-Received:Thu X-HELO: mail-oi0-f51.google.com Received: from mail-oi0-f51.google.com (HELO mail-oi0-f51.google.com) (209.85.218.51) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 23 Feb 2017 09:02:06 +0000 Received: by mail-oi0-f51.google.com with SMTP id 62so14491511oih.2 for ; Thu, 23 Feb 2017 01:02:06 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=Za7lasQn9+34ETTHUE1rMQXzYIOb7myoBGM/5zEvriE=; b=GY6DQzD7NO6kvUG1LdHb8/C6wCAFaWH3neLvSk4aE6WEGLd+RNgNgSz2MpWQ6Fqn91 yyN1OYjlwAmFP1HRtOvM9iHOuW7v/JS1KRi8hgejvxoefij8L9QkG1+iXk6WED9Z97xp l3MR93z3JVhhdVDawZl1dqdcRxTGODGJFzkCF99qlKqTqSWZBEXsjRm7MnyivxV1l21p XLa6JNMtI+sYeMeo2J+T1kcVT11EscxEujzQE6BcI2yJao/tAoRlsLq8TVpQIn2vZto4 WAtSFI5VQebUQChFG2fhBATOjGSMHpS1o2oRJgAf6puChXTaJk0ckrIN/V3c6EgZa6sG Z/bA== X-Gm-Message-State: AMke39mrhQoyS+sH18i/+D0IppcRAgrmyFHOvlP5wQ4+CsxB05MLTDZejAclx1WtmSXcEM29rzZCBwK4/MLqyw== X-Received: by 10.202.94.194 with SMTP id s185mr20694661oib.196.1487840525521; Thu, 23 Feb 2017 01:02:05 -0800 (PST) MIME-Version: 1.0 Received: by 10.157.40.120 with HTTP; Thu, 23 Feb 2017 01:02:05 -0800 (PST) In-Reply-To: <5d9c026a-12a7-d6f7-e1d7-da0382ac8f2a@redhat.com> References: <5d9c026a-12a7-d6f7-e1d7-da0382ac8f2a@redhat.com> From: Richard Biener Date: Thu, 23 Feb 2017 09:44:00 -0000 Message-ID: Subject: Re: [PATCH][PR tree-optimization/79578] Use operand_equal_p rather than pointer equality for base test To: Jeff Law Cc: gcc-patches Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2017-02/txt/msg01434.txt.bz2 On Thu, Feb 23, 2017 at 6:49 AM, Jeff Law wrote: > > tree-ssa-dse.c needs to verify when two writes have the same base address. > Right now it uses pointer equality. The testcase in BZ79578 shows that we > should have been using operand_equal_p. > > This one-liner fixes that oversight. Bootstrapped and regression tested on > x86_64-linux-gnu. Installed on the trunk. > > Jeff > > commit ef506ec9114a7fe27d9ee892c17edd100f72a963 > Author: law > Date: Thu Feb 23 05:47:43 2017 +0000 > > PR tree-optimization/79578 > * tree-ssa-dse.c (clear_bytes_written_by): Use operand_equal_p > to compare base operands. > > PR tree-optimization/79578 > * g++.dg/tree-ssa/ssa-dse-3.C: New test. > > git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@245675 > 138bc75d-0d04-0410-961f-82ee72b054a4 > > diff --git a/gcc/ChangeLog b/gcc/ChangeLog > index 7155850..6da1d74 100644 > --- a/gcc/ChangeLog > +++ b/gcc/ChangeLog > @@ -1,3 +1,9 @@ > +2017-02-22 Jeff Law > + > + PR tree-optimization/79578 > + * tree-ssa-dse.c (clear_bytes_written_by): Use operand_equal_p > + to compare base operands. > + > 2017-02-22 Segher Boessenkool > > PR target/79211 > diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog > index ea5e251..d900cc3 100644 > --- a/gcc/testsuite/ChangeLog > +++ b/gcc/testsuite/ChangeLog > @@ -1,3 +1,8 @@ > +2017-02-22 Jeff Law > + > + PR tree-optimization/79578 > + * g++.dg/tree-ssa/ssa-dse-3.C: New test. > + > 2017-02-22 Sameera Deshpande > > * gcc.target/mips/msa-fp-cc.c: New test. > diff --git a/gcc/testsuite/g++.dg/tree-ssa/ssa-dse-3.C > b/gcc/testsuite/g++.dg/tree-ssa/ssa-dse-3.C > new file mode 100644 > index 0000000..fe8f309 > --- /dev/null > +++ b/gcc/testsuite/g++.dg/tree-ssa/ssa-dse-3.C > @@ -0,0 +1,28 @@ > +/* { dg-do compile } */ > +/* { dg-options "-std=c++14 -O3 -fdump-tree-dse1-details" } */ > + > +#include > +#include > + > +struct A > +{ > + std::uint16_t a, b; > +}; > + > +A* f(char* b) __attribute__((noinline)); > + > +A* f(char* b) { > + auto a = new(b) A{}; > + a->a = 1; > + a->b = 2; > + return a; > +} > + > +int main() { > + char b[sizeof(A)] alignas(A); > + f(b); > +} > + > + > +/* { dg-final { scan-tree-dump "Deleted dead store: " "dse1" } } */ > + > diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c > index 84c0b11..a82e164 100644 > --- a/gcc/tree-ssa-dse.c > +++ b/gcc/tree-ssa-dse.c > @@ -176,7 +176,7 @@ clear_bytes_written_by (sbitmap live_bytes, gimple > *stmt, ao_ref *ref) > /* Verify we have the same base memory address, the write > has a known size and overlaps with REF. */ > if (valid_ao_ref_for_dse (&write) > - && write.base == ref->base > + && operand_equal_p (write.base, ref->base, 0) As you've identified size and offset match you are really interested in comparing the base addresses and thus should use OEP_ADDRESS_OF. Richard. > && write.size == write.max_size > && ((write.offset < ref->offset > && write.offset + write.size > ref->offset) >