From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33724) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZluDX-00020X-3R for qemu-devel@nongnu.org; Tue, 13 Oct 2015 03:41:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZluDT-00077Y-SJ for qemu-devel@nongnu.org; Tue, 13 Oct 2015 03:41:51 -0400 Received: from mail-wi0-x236.google.com ([2a00:1450:400c:c05::236]:32862) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZluDT-00077S-MI for qemu-devel@nongnu.org; Tue, 13 Oct 2015 03:41:47 -0400 Received: by wicge5 with SMTP id ge5so44879371wic.0 for ; Tue, 13 Oct 2015 00:41:47 -0700 (PDT) Sender: Paolo Bonzini References: <1444643442-8487-1-git-send-email-pbonzini@redhat.com> <561C3120.9080402@twiddle.net> From: Paolo Bonzini Message-ID: <561CB5B8.3040307@redhat.com> Date: Tue, 13 Oct 2015 09:41:44 +0200 MIME-Version: 1.0 In-Reply-To: <561C3120.9080402@twiddle.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] target-i386: fix pcmpxstrx equal-ordered (strstr) mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson , qemu-devel@nongnu.org Cc: fweimer@redhat.com, Eduardo Habkost On 13/10/2015 00:16, Richard Henderson wrote: > On 10/12/2015 08:50 PM, Paolo Bonzini wrote: >> In this mode, referring an invalid element of the source forces the >> result to false (table 4-7, last column) but referring an invalid >> element of the destination forces the result to true, so the outer >> loop should still be run even if some elements of the destination >> will be invalid. They will be culled in the inner loop, which >> correctly bounds "i" to validd. >> >> This fix tst_strstr in glibc 2.17. >> >> Reported-by: Florian Weimer >> Cc: Richard Henderson >> Cc: Eduardo Habkost >> Signed-off-by: Paolo Bonzini >> --- >> target-i386/ops_sse.h | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/target-i386/ops_sse.h b/target-i386/ops_sse.h >> index 7aa693a..268f3e1 100644 >> --- a/target-i386/ops_sse.h >> +++ b/target-i386/ops_sse.h >> @@ -2037,7 +2037,7 @@ static inline unsigned pcmpxstrx(CPUX86State >> *env, Reg *d, Reg *s, >> } >> break; >> case 3: >> - for (j = valids - validd; j >= 0; j--) { >> + for (j = valids; j >= 0; j--) { >> res <<= 1; >> v = 1; >> for (i = MIN(upper - j, validd); i >= 0; i--) { > > I don't see how the bounding is properly done. In particular, > >> v &= (pcmp_val(s, ctrl, i + j) == pcmp_val(d, ctrl, i)); > > We're bounding j by valids, but accessing i+j? You're absolutely right, the second loop also needs s/upper/valids/. Paolo