From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH rdma-core 2/2] mlx5: Convert explicitly to signed char Date: Wed, 30 Aug 2017 10:49:52 -0600 Message-ID: <20170830164952.GA9310@obsidianresearch.com> References: <1504102764-21638-1-git-send-email-yishaih@mellanox.com> <1504102764-21638-3-git-send-email-yishaih@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1504102764-21638-3-git-send-email-yishaih-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Yishai Hadas Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, majd-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org List-Id: linux-rdma@vger.kernel.org On Wed, Aug 30, 2017 at 05:19:24PM +0300, Yishai Hadas wrote: > From: Leon Romanovsky > > The 0x80 value is a canonical way to mark as not-used in intrinsics > function calls. This commit message is not good, try: _mm_shuffle_epi8 requires 0x80 to set the output byte to zero, but _mm_set_epi8() accepts char. If gcc is compiling in a configuration with a signed char then it can produce a -Werror=overflow warning. And this fix is wrong, since it just moves the warning to configurations that have an unsigned char. (eg -funsigned-char) It is really broken that the _mm_set_epi uses a char as input :| I think you need to do this instead: #include #if CHAR_MIN < 0 #define SHUFFLE_IGNORE -128 #else #define SHUFFLE_IGNORE 0x80 #endif Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html