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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-439b02ce65dsm41102595e9.1.2025.02.22.01.11.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Feb 2025 01:11:29 -0800 (PST) Date: Sat, 22 Feb 2025 09:11:28 +0000 From: David Laight To: I Hsin Cheng Cc: yury.norov@gmail.com, anshuman.khandual@arm.com, arnd@arndb.de, linux-kernel@vger.kernel.org, jserv@ccns.ncku.edu.tw, skhan@linuxfoundation.org, mka@chromium.org, akpm@linux-foundation.org Subject: Re: [PATCH v2] uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)" Message-ID: <20250222091128.5429f1c2@pumpkin> In-Reply-To: <20250221074208.832153-1-richard120310@gmail.com> References: <20250221074208.832153-1-richard120310@gmail.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 21 Feb 2025 15:41:49 +0800 I Hsin Cheng wrote: > This patch reverts 'commit c32ee3d9abd2("bitops: avoid integer overflow in > GENMASK(_ULL)")'. > > The code generation can be shrink by over 1k by reverting the commit. While you are setup for testing this (and me being lazy) does changing the definition to be: (2u << hi) - (1u << lo) make it any smaller. (A summary of the size summary would do, no point listing lots of '-1') That can also be written: ((one + one) << hi) - (one << lo) so an appropriately typed 'one' (1, 1u, 1ul, 1ull, (__uint128)1 etc) can be passed. David