From patchwork Tue Aug 2 08:37:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Liebler X-Patchwork-Id: 14237 Received: (qmail 69547 invoked by alias); 2 Aug 2016 08:37:17 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 69536 invoked by uid 89); 2 Aug 2016 08:37:17 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=BAYES_00, FSL_HELO_NON_FQDN_1, KAM_LAZY_DOMAIN_SECURITY autolearn=no version=3.3.2 spammy=1.4, 1995, jz1, H*r:Unknown X-HELO: blaine To: libc-alpha@sourceware.org From: Stefan Liebler Subject: Re: [PATCH] Get rid of array-bounds warning in __kernel_rem_pio2[f] with gcc 6.1 -O3. Date: Tue, 2 Aug 2016 10:37:03 +0200 Lines: 88 Message-ID: References: <577E1156.2030604@linux.vnet.ibm.com> <20160801141200.GW6702@vapier.lan> Mime-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2 In-Reply-To: <20160801141200.GW6702@vapier.lan> On 08/01/2016 04:12 PM, Mike Frysinger wrote: > On 25 Jul 2016 17:55, Stefan Liebler wrote: >> + /* On s390x gcc 6.1 -O3 produces the warning "array subscript is below >> + array bounds [-Werror=array-bounds]". Only __ieee754_rem_pio2l() >> + calls __kernel_rem_pio2f() for normal numbers and |x| > 3pi/4. Thus >> + x can't be zero and ipio2 is not zero, too. Thus not all iq[] >> + values can't be zero. */ > > GNU style puts two spaces after the period > -mike > Oops. I missed that. Here is an update. Thanks. Stefan diff --git a/sysdeps/ieee754/dbl-64/k_rem_pio2.c b/sysdeps/ieee754/dbl-64/k_rem_pio2.c index e58c9e8..db0a657 100644 --- a/sysdeps/ieee754/dbl-64/k_rem_pio2.c +++ b/sysdeps/ieee754/dbl-64/k_rem_pio2.c @@ -132,6 +132,7 @@ static char rcsid[] = "$NetBSD: k_rem_pio2.c,v 1.7 1995/05/10 20:46:25 jtc Exp $ #include #include +#include static const int init_jk[] = {2,3,4,6}; /* initial value for jk */ @@ -251,8 +252,16 @@ recompute: j |= iq[i]; if (j == 0) /* need recomputation */ { + /* On s390x gcc 6.1 -O3 produces the warning "array subscript is below + array bounds [-Werror=array-bounds]". Only __ieee754_rem_pio2l() + calls __kernel_rem_pio2f() for normal numbers and |x| > 3pi/4. + Thus x can't be zero and ipio2 is not zero, too. Thus not all iq[] + values can't be zero. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (6.1, "-Warray-bounds"); for (k = 1; iq[jk - k] == 0; k++) ; /* k = no. of terms needed */ + DIAG_POP_NEEDS_COMMENT; for (i = jz + 1; i <= jz + k; i++) /* add q[jz+1] to q[jz+k] */ { diff --git a/sysdeps/ieee754/flt-32/k_rem_pio2f.c b/sysdeps/ieee754/flt-32/k_rem_pio2f.c index 392afdb..cca20aa 100644 --- a/sysdeps/ieee754/flt-32/k_rem_pio2f.c +++ b/sysdeps/ieee754/flt-32/k_rem_pio2f.c @@ -19,6 +19,7 @@ static char rcsid[] = "$NetBSD: k_rem_pio2f.c,v 1.4 1995/05/10 20:46:28 jtc Exp #include #include +#include /* In the float version, the input parameter x contains 8 bit integers, not 24 bit integers. 113 bit precision is not supported. */ @@ -122,7 +123,16 @@ recompute: j = 0; for (i=jz-1;i>=jk;i--) j |= iq[i]; if(j==0) { /* need recomputation */ + /* On s390x gcc 6.1 -O3 produces the warning "array subscript is + below array bounds [-Werror=array-bounds]". Only + __ieee754_rem_pio2f() calls __kernel_rem_pio2f() for normal + numbers and |x| ~> 2^7*(pi/2). Thus x can't be zero and + ipio2 is not zero, too. Thus not all iq[] values can't be + zero. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (6.1, "-Warray-bounds"); for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */ + DIAG_POP_NEEDS_COMMENT; for(i=jz+1;i<=jz+k;i++) { /* add q[jz+1] to q[jz+k] */ f[jx+i] = (float) ipio2[jv+i];