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From: Segher Boessenkool <segher@kernel.crashing.org>
To: Fangrui Song <maskray@sourceware.org>
Cc: Indu Bhagat <indu.bhagat@oracle.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Jan Beulich <jbeulich@suse.com>,
	Rainer Orth <ro@cebitec.uni-bielefeld.de>,
	"linux-toolchains@vger.kernel.org"
	<linux-toolchains@vger.kernel.org>,
	Jens Remus <jremus@linux.ibm.com>,
	Sterling Augustine <saugustine@google.com>,
	Pavel Labath <labath@google.com>,
	Andrii Nakryiko <andrii@kernel.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Serhei Makarov <smakarov@redhat.com>,
	Binutils <binutils@sourceware.org>
Subject: Re: Unaligned access trade-offs for SFrame FRE layout
Date: Tue, 16 Sep 2025 11:44:26 -0500	[thread overview]
Message-ID: <aMmT6q1jERmMq-AR@gate> (raw)
In-Reply-To: <CAN30aBFW1T7WhBn9QBDig6i1Nh23XTJ1eRFHeNLNU2nfahv_7Q@mail.gmail.com>

On Tue, Sep 16, 2025 at 09:32:30AM -0700, Fangrui Song wrote:
> The read32le(p) function is either a standard read or a byte-swapped
> read.

You should never overcomplicate things by doing byte-swaps.  Instead,
just say what you mean:

u32 read32le(u8 *p)
{
	return p[0] + 0x100*p[1] + 0x10000*p[2] + 0x1000000*p[3];
}

or something like that.  The compiler can optimise such things just
fine!  There is no need to go via extra indirections.


Segher

  reply	other threads:[~2025-09-16 16:44 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-09-12 17:34 Unaligned access trade-offs for SFrame FRE layout Indu Bhagat
2025-09-12 18:19 ` Segher Boessenkool
2025-09-12 19:18 ` Steven Rostedt
2025-09-13  7:56   ` Indu Bhagat
2025-09-15 16:04     ` Steven Rostedt
     [not found]   ` <CAEG7qUxk_cZYv3X_VM6+ZGaVFAD-7jdPd3xA92xYHUAqyzb2Xw@mail.gmail.com>
2025-09-13  8:01     ` Indu Bhagat
2025-09-14 14:14 ` Jan Beulich
2025-09-14 14:39   ` Rainer Orth
2025-09-14 15:23     ` Jan Beulich
2025-09-14 16:18       ` Rainer Orth
2025-09-14 18:10         ` Jan Beulich
2025-09-15  5:42           ` Indu Bhagat
2025-09-15 16:07             ` Steven Rostedt
2025-09-15 17:22               ` Segher Boessenkool
2025-09-16  6:05               ` Fangrui Song
2025-09-16 15:58                 ` Steven Rostedt
2025-09-18 10:39                   ` Jens Remus
2025-09-16 16:03                 ` Indu Bhagat
2025-09-16 16:32                   ` Fangrui Song
2025-09-16 16:44                     ` Segher Boessenkool [this message]
2025-09-16 17:05                       ` Fangrui Song
2025-09-16 17:54                       ` Segher Boessenkool
2025-09-16 17:33                     ` Indu Bhagat
2025-09-17 21:12                 ` Steven Rostedt
2025-09-17 23:55                   ` Alan Modra
2025-09-15  9:08       ` Segher Boessenkool

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