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From: Junio C Hamano <gitster@pobox•com>
To: Jeff King <peff@peff•net>
Cc: git@vger•kernel.org, Duy Nguyen <pclouds@gmail•com>,
	Christian Couder <christian.couder@gmail•com>
Subject: Re: [PATCH 1/2] avoid shifting signed integers 31 bits
Date: Tue, 29 Dec 2015 16:09:21 -0800	[thread overview]
Message-ID: <xmqq4mf0g5la.fsf@gitster.mtv.corp.google.com> (raw)
In-Reply-To: <20151229063545.GA30340@sigill.intra.peff.net> (Jeff King's message of "Tue, 29 Dec 2015 01:35:46 -0500")

Jeff King <peff@peff•net> writes:

> diff --git a/diff.h b/diff.h
> index f7208ad..893f446 100644
> --- a/diff.h
> +++ b/diff.h
> @@ -91,7 +91,7 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
>  #define DIFF_OPT_DIRSTAT_BY_LINE     (1 << 28)
>  #define DIFF_OPT_FUNCCONTEXT         (1 << 29)
>  #define DIFF_OPT_PICKAXE_IGNORE_CASE (1 << 30)
> -#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1 << 31)
> +#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1U << 31)
>  
>  #define DIFF_OPT_TST(opts, flag)    ((opts)->flags & DIFF_OPT_##flag)
>  #define DIFF_OPT_TOUCHED(opts, flag)    ((opts)->touched_flags & DIFF_OPT_##flag)

Thanks.

Seeing (1 << 30) and (1U <<31) together made me feel that we are way
_too_ explicit being careful about 32-bit archs (iow, it would be
more consistent to turn all of these "1 <<" into "1U <<"), but at
the same time, (1 << 30) won't be broken unless we are on 31-bit
arch in the sense that if we are on 30-bit or smaller arch the
expression is already broken with or without "U", and if we are on
32-bit or more, then with or without "U" we are OK---which made me
feel somewhat funny.

In any case, these two are good changes.  Thanks.

next prev parent reply	other threads:[~2015-12-30  0:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-29  6:34 [PATCH 0/2] compiling with -fsanitize=undefined Jeff King
2015-12-29  6:35 ` [PATCH 1/2] avoid shifting signed integers 31 bits Jeff King
2015-12-30  0:09   ` Junio C Hamano [this message]
2015-12-30  4:25     ` Jeff King
2015-12-31  5:10   ` Duy Nguyen
2015-12-31  5:20     ` Jeff King
2016-01-04 17:52       ` Junio C Hamano
2016-01-04 23:32         ` Jeff King
2015-12-29  6:36 ` [PATCH 2/2] bswap: add NO_UNALIGNED_LOADS define Jeff King
2015-12-29  6:42   ` Eric Sunshine
2015-12-29  6:45     ` Jeff King
2015-12-29  6:44 ` [PATCH 0/2] compiling with -fsanitize=undefined Jeff King

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