From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leon Romanovsky Subject: Re: [PATCH rdma-core 1/5] Pull uninitialized_var into util/compiler.h Date: Tue, 11 Oct 2016 22:46:33 +0300 Message-ID: <20161011194633.GP9282@leon.nu> References: <1475879772-29458-1-git-send-email-jgunthorpe@obsidianresearch.com> <1475879772-29458-2-git-send-email-jgunthorpe@obsidianresearch.com> <20161009054601.GB9282@leon.nu> <20161009230150.GB12551@obsidianresearch.com> <20161010040930.GF9282@leon.nu> <20161011180517.GA17866@obsidianresearch.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9rkt7tfZQigMla7f" Return-path: Content-Disposition: inline In-Reply-To: <20161011180517.GA17866-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jason Gunthorpe Cc: Doug Ledford , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org --9rkt7tfZQigMla7f Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Oct 11, 2016 at 12:05:17PM -0600, Jason Gunthorpe wrote: > On Mon, Oct 10, 2016 at 07:09:30AM +0300, Leon Romanovsky wrote: > > > > I think people would complain about the extra stores. gcc 6 will > > > eliminate them, but older compilers will not. > > > > This unintialized_var(x) adds extra store too (... x = x ...). > > I have confirmed that the unintialized_var macro does not impact code > generation on the old gccs while the =0 approach does. Ohh, thanks. But I'm still left under impression of this article [1] that using such macro is a bad thing and we are "punishing" all users of modern compilers. [1] https://lwn.net/Articles/529954/ > > So no extra store. > > Jason --9rkt7tfZQigMla7f Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJX/UGZAAoJEORje4g2clinME4P/jVCkdWH77jcRSe6LtD7eOo9 rmTonvCKKKhqzPJ8Qq0nr1EyBrhnclscdkyxW0xeLZMD0MpXTQLC3EFdbywVptfZ zU/mt0OoOg1rs8czeValDIpZ4lIpQPzegsOnN0DwKd4vRlxXsiAzKNNS5f6yrM8B FAlDSl9/gmXhQiNelXl6Sr0fUHKvSt5ErX+gUXekDFT6TFBiU18fG8fcS4++Hg2i M2EDKpqnVOHz+CENAOfm7n1QN0ufZPrpZ5oH8tgo0HC9QScAkWt7qxcRPKAdYqkP LIqQ9p2r72xFodjQgxOTJxb8ExNDOwYom3+0a+dCiuN0Kq6NaNHIQXJB4pIGiurD SA662KyNT4uAqotZbGN5/YHAP8gClfsbLmUYXSCLg1B/F8sksiaiO6bt/SRUVnr7 7r3JSfY6G8Q13AdnoEf56+mkyqNgbUEB0/r9RJzFxDPjz1PFLFUcUrqLiEze0AwR W045Yvuo4FP8nKkP1cVj3ymC3Vb7mWxdPrQE3TOVD/IDWq1xSHb0di9OCEIK7wJA 9mX9qnMggLdw3jWEZTo+8uYLowg7U0hLmCl/LWxWn/06Xb7dG5PI73qdxEx32zSt AnLf56zrBHu+6HRZ4Gg10EuVCxQROFT4SzNSWnsKba2G2YLLayJPotuPXFPv8tu/ CErQPgEHT3pgMrKo/IDV =NTKb -----END PGP SIGNATURE----- --9rkt7tfZQigMla7f-- -- 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