From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randolph Chung Subject: Re: [PATCH] misplaced parenthesis? Date: Mon, 18 May 2009 09:42:50 +0800 Message-ID: <4A10BD1A.3060208@tausq.org> References: <4A0DC131.8020606@gmail.com> <4A0E3D95.5090404@tausq.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: Roel Kluin , kyle@mcmartin.ca, linux-parisc@vger.kernel.org, Andrew Morton To: Matt Turner Return-path: In-Reply-To: List-ID: List-Id: linux-parisc.vger.kernel.org The wrong version of course produces different code.... the original and the corrected one may produce different code depending on how the compiler schedules things. randolph Matt Turner wrote: > Does gcc produce different code for the three variations? > > Matt > > On Sat, May 16, 2009 at 12:14 AM, Randolph Chung wrote: > >> This is a bit confusingly written, but your patch does not appear to be >> correct. >> >> == has higher precedence than &, so you are basically changing it to: >> if (likely(t1 & 1)) >> >> it really should be >> >> - if (likely(t1 & (sizeof(unsigned int)-1)) == 0) { >> + if (likely((t1 & (sizeof(unsigned int)-1)) == 0)) { >> >> randolph >> >> >> Roel Kluin wrote: >> >>> Fix misplaced parenthesis. >>> >>> Signed-off-by: Roel Kluin >>> --- >>> I think this is what was intended? Note that this patch may affect >>> profiling. >>> >>> diff --git a/arch/parisc/lib/memcpy.c b/arch/parisc/lib/memcpy.c >>> index bbda909..30207b0 100644 >>> --- a/arch/parisc/lib/memcpy.c >>> +++ b/arch/parisc/lib/memcpy.c >>> @@ -405,7 +405,7 @@ byte_copy: >>> unaligned_copy: >>> /* possibly we are aligned on a word, but not on a double... */ >>> - if (likely(t1 & (sizeof(unsigned int)-1)) == 0) { >>> + if (likely(t1 & (sizeof(unsigned int)-1) == 0)) { >>> t2 = src & (sizeof(unsigned int) - 1); >>> if (unlikely(t2 != 0)) { >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-parisc" in >>> the body of a message to majordomo@vger.kernel.org >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-parisc" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-parisc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >