From patchwork Sat Mar 15 07:42:25 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Tokarev X-Patchwork-Id: 14017829 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 24DEAC28B28 for ; Sat, 15 Mar 2025 07:50:40 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ttMCV-00064Z-6T; Sat, 15 Mar 2025 03:44:55 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ttMCC-0004vi-Ho; Sat, 15 Mar 2025 03:44:38 -0400 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ttMCA-00051t-KY; Sat, 15 Mar 2025 03:44:36 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id DB673FFB0B; Sat, 15 Mar 2025 10:41:55 +0300 (MSK) Received: from gandalf.tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with ESMTP id CA1351CACD5; Sat, 15 Mar 2025 10:42:49 +0300 (MSK) Received: by gandalf.tls.msk.ru (Postfix, from userid 1000) id 8EF0655A02; Sat, 15 Mar 2025 10:42:49 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Max Chou , Daniel Henrique Barboza , Alistair Francis , Michael Tokarev Subject: [Stable-8.2.10 23/42] target/riscv: rvv: Fix unexpected behavior of vector reduction instructions when vl is 0 Date: Sat, 15 Mar 2025 10:42:25 +0300 Message-Id: <20250315074249.634718-23-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Max Chou According to the Vector Reduction Operations section in the RISC-V "V" Vector Extension spec, "If vl=0, no operation is performed and the destination register is not updated." The vd should be updated when vl is larger than 0. Fixes: fe5c9ab1fc ("target/riscv: vector single-width integer reduction instructions") Fixes: f714361ed7 ("target/riscv: rvv-1.0: implement vstart CSR") Signed-off-by: Max Chou Reviewed-by: Daniel Henrique Barboza Message-ID: <20250124101452.2519171-1-max.chou@sifive.com> Signed-off-by: Alistair Francis (cherry picked from commit ffd455963f230c7dc04965609d6675da687a5a78) Signed-off-by: Michael Tokarev diff --git a/target/riscv/vector_helper.c b/target/riscv/vector_helper.c index ddbbdef577..69ac3d5b47 100644 --- a/target/riscv/vector_helper.c +++ b/target/riscv/vector_helper.c @@ -4430,7 +4430,9 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ } \ s1 = OP(s1, (TD)s2); \ } \ - *((TD *)vd + HD(0)) = s1; \ + if (vl > 0) { \ + *((TD *)vd + HD(0)) = s1; \ + } \ env->vstart = 0; \ /* set tail elements to 1s */ \ vext_set_elems_1s(vd, vta, esz, vlenb); \ @@ -4516,7 +4518,9 @@ void HELPER(NAME)(void *vd, void *v0, void *vs1, \ } \ s1 = OP(s1, (TD)s2, &env->fp_status); \ } \ - *((TD *)vd + HD(0)) = s1; \ + if (vl > 0) { \ + *((TD *)vd + HD(0)) = s1; \ + } \ env->vstart = 0; \ /* set tail elements to 1s */ \ vext_set_elems_1s(vd, vta, esz, vlenb); \