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[174.21.76.141]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1fac15693e8sm18108665ad.217.2024.06.28.10.54.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 28 Jun 2024 10:54:32 -0700 (PDT) Message-ID: <627f05b5-7abe-423f-829e-4215bcf1bccd@linaro.org> Date: Fri, 28 Jun 2024 10:54:30 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 02/23] target/i386: fix gen_prepare_size_nz condition To: =?UTF-8?Q?Alex_Benn=C3=A9e?= , qemu-devel@nongnu.org References: <20240628124258.832466-1-alex.bennee@linaro.org> <20240628124258.832466-3-alex.bennee@linaro.org> Content-Language: en-US From: Richard Henderson In-Reply-To: <20240628124258.832466-3-alex.bennee@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::62a; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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 On 6/28/24 05:42, Alex Bennée wrote: > Incorrect brace positions causes an unintended overflow on 32 bit > builds and shenanigans result. > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2413 > Suggested-by: Mark Cave-Ayland > Signed-off-by: Alex Bennée > --- > target/i386/tcg/translate.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c > index ad1819815a..94f13541c3 100644 > --- a/target/i386/tcg/translate.c > +++ b/target/i386/tcg/translate.c > @@ -877,7 +877,7 @@ static CCPrepare gen_prepare_sign_nz(TCGv src, MemOp size) > return (CCPrepare) { .cond = TCG_COND_LT, .reg = src }; > } else { > return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = src, > - .imm = 1ull << ((8 << size) - 1) }; > + .imm = (1ull << (8 << size)) - 1 }; This is incorrect -- we want only to test the sign bit. Perhaps MAKE_64BIT_MASK((8 << size) - 1, 1) would make this more explicit? I'll have a quick look at the issue and see if I can reproduce. r~