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From: "René Scharfe" <l.s.r@web.de>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Cc: Git List <git@vger.kernel.org>, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 1/5] add SWAP macro
Date: Mon, 30 Jan 2017 17:48:00 +0100	[thread overview]
Message-ID: <9bcae427-d654-a671-4368-030150168102@web.de> (raw)
In-Reply-To: <alpine.DEB.2.20.1701301637570.3469@virtualbox>

Am 30.01.2017 um 16:39 schrieb Johannes Schindelin:
> Hi René,
>
> On Sat, 28 Jan 2017, René Scharfe wrote:
>
>> Add a macro for exchanging the values of variables.  It allows users to
>> avoid repetition and takes care of the temporary variable for them.  It
>> also makes sure that the storage sizes of its two parameters are the
>> same.  Its memcpy(1) calls are optimized away by current compilers.
>
> How certain are we that "current compilers" optimize that away? And about
> which "current compilers" are we talking? GCC? GCC 6? Clang? Clang 3?
> Clang 3.8.*? Visual C 2005+?

GCC 4.4.7 and clang 3.2 on x86-64 compile the macro to the same object 
code as a manual swap ; see https://godbolt.org/g/F4b9M9.  Both were 
released 2012.  That website doesn't offer Visual C(++), but since you 
added the original macro in e5a94313c0 ("Teach git-apply about '-R'", 
2006) I guess we have that part covered. ;)

René

  reply	other threads:[~2017-01-30 16:51 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-28 21:13 [PATCH 0/5] introduce SWAP macro René Scharfe
2017-01-28 21:38 ` [PATCH 1/5] add " René Scharfe
2017-01-30 15:39   ` Johannes Schindelin
2017-01-30 16:48     ` René Scharfe [this message]
2017-01-30 20:48       ` Johannes Schindelin
2017-01-30 21:46         ` René Scharfe
2017-01-31 12:13           ` Johannes Schindelin
2017-01-31 21:02             ` René Scharfe
2017-02-01  0:44               ` Ramsay Jones
2017-02-01 11:39               ` Johannes Schindelin
2017-01-30 16:01   ` Johannes Schindelin
2017-01-30 16:59     ` René Scharfe
2017-01-30 18:41     ` Johannes Sixt
2017-01-30 21:03       ` Johannes Schindelin
2017-01-30 22:09         ` René Scharfe
2017-01-30 22:21           ` Brandon Williams
2017-01-31 21:03             ` René Scharfe
2017-01-31 21:35               ` Jeff King
2017-01-31 22:29                 ` Junio C Hamano
2017-01-31 22:36                   ` Jeff King
2017-02-01 11:28                 ` Johannes Schindelin
2017-02-01 11:47                   ` Jeff King
2017-02-01 18:06                     ` René Scharfe
2017-02-01 18:33                       ` Junio C Hamano
2017-02-07 22:04                         ` René Scharfe
2017-02-07 22:30                           ` Junio C Hamano
2017-02-08 15:14                             ` Johannes Schindelin
2017-01-31 12:03           ` Johannes Schindelin
2017-04-24 11:29   ` Jeff King
2017-04-24 11:49     ` Jeff King
2017-04-24 13:13       ` Duy Nguyen
2017-04-28 17:04     ` René Scharfe
2017-04-28 21:49       ` Jeff King
2017-04-29 18:16         ` René Scharfe
2017-04-30  3:11           ` Jeff King
2017-05-02  5:29             ` René Scharfe
2017-01-28 21:40 ` [PATCH 2/5] apply: use " René Scharfe
2017-01-28 21:40 ` [PATCH 3/5] " René Scharfe
2017-01-30 16:03   ` Johannes Schindelin
2017-01-30 17:18     ` René Scharfe
2017-01-30 22:22   ` Junio C Hamano
2017-01-31 21:02     ` René Scharfe
2017-01-28 21:41 ` [PATCH 4/5] diff: " René Scharfe
2017-01-30 16:04   ` Johannes Schindelin
2017-01-30 17:26     ` René Scharfe
2017-01-30 22:22   ` Junio C Hamano
2017-01-28 21:42 ` [PATCH 5/5] graph: " René Scharfe
2017-01-30 16:16   ` Johannes Schindelin
2017-01-30 17:41     ` René Scharfe
2017-01-30 23:20 ` [PATCH 0/5] introduce " Junio C Hamano

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