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[209.85.208.48]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a7acadb81d6sm89432266b.193.2024.07.25.10.03.02 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 25 Jul 2024 10:03:02 -0700 (PDT) Received: by mail-ed1-f48.google.com with SMTP id 4fb4d7f45d1cf-59589a9be92so1575851a12.2 for ; Thu, 25 Jul 2024 10:03:02 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCVq8HbcIOF2zDtK5F01dOX/7NSLOPhqguRnRIb7HMDwacHTKnwuTxS/nWxKBckXtujetGevT/tWKbODivoFUkalDxM= X-Received: by 2002:a05:6402:3587:b0:5a1:c43:82ca with SMTP id 4fb4d7f45d1cf-5ac2c1c73b3mr2343280a12.26.1721926981090; Thu, 25 Jul 2024 10:03:01 -0700 (PDT) MIME-Version: 1.0 References: <23bdb6fc8d884ceebeb6e8b8653b8cfe@AcuMS.aculab.com> <03601661326c4efba4e618ead15fa0e2@AcuMS.aculab.com> <5a129d04e0b84b48ba6c5189a047ac8f@AcuMS.aculab.com> In-Reply-To: <5a129d04e0b84b48ba6c5189a047ac8f@AcuMS.aculab.com> From: Linus Torvalds Date: Thu, 25 Jul 2024 10:02:45 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 4/7] minmax: Simplify signedness check To: David Laight Cc: Arnd Bergmann , "linux-kernel@vger.kernel.org" , Matthew Wilcox , Christoph Hellwig , Andrew Morton , Andy Shevchenko , Dan Carpenter , "Jason A . Donenfeld" , "pedro.falcato@gmail.com" , Mateusz Guzik , "linux-mm@kvack.org" Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Queue-Id: 84B9710003D X-Rspamd-Server: rspam01 X-Stat-Signature: 1buekux5wummgm6miyowmq5n6a39oz99 X-HE-Tag: 1721926985-902757 X-HE-Meta: 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 zfoW6ex8 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 25 Jul 2024 at 02:01, David Laight wrote: > > The condition is '>= 0' so it doesn't matter if it is '1' or '0'. Yes, but that's because the whole conditional is so inexplicably complex. But the explanation is: > That gives a 'comparison of unsigned type against 0 is always true' warning. > (The compiler generates that for code in the unused branches of both > __builtin_choose_expr() and _Generic().) > Moving the comparison to the outer level stops all such compiler warnings. Christ. This whole series is a nightmare of "add complexity to deal with stupid issues". But the kernel test robot clearly found even more issues. I think we need to just go back to the old code. It was stupid and limited and caused us to have to be more careful about types than was strictly necessary. But it was also about a million times simpler, and didn't cause build time regressions. Linus