[debbugs-tracker] bug#32485: closed (27.0.50; Problem with zerop on 32-bit platforms)

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Your message dated Tue, 21 Aug 2018 13:54:11 -0700
with message-id <address@hidden>
and subject line Re: bug#32485: 27.0.50; Problem with zerop on 32-bit platforms
has caused the debbugs.gnu.org bug report #32485,
regarding 27.0.50; Problem with zerop on 32-bit platforms
to be marked as done.

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32485: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=32485
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> --- Begin Message ---
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> Subject: 
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> 27.0.50; Problem with zerop on 32-bit platforms
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> Date: 
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> Mon, 20 Aug 2018 14:12:54 -0400
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> User-agent: 
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> Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
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> Evaluating (zerop (lsh -1 32)) on 32-bit Cygwin yields
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> Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p 
> -4294967296)
>
> I realize that the fate of lsh is still being debated, but I think
> there's a problem with zerop anyway, because directly evaluating (zerop
> -4294967296) leads to the same error.
>
> I encountered this problem because vc-hg-state-fast contains the
> following:
>
>          ;; We want to store 32-bit unsigned values in fixnums.
>          (zerop (lsh -1 32))
>
> Aside from the fact that this leads to an error, it may need to be
> changed once a decision is made about lsh.
>
>
>
> In GNU Emacs 27.0.50 (build 10, i686-pc-cygwin)
>  of 2018-08-20 built on moufang
> Repository revision: ecd7a9407711ebe24d7e07d4402a2d66754ee693
>
>
>
>
> --- End Message ---

--- Begin Message --- Subject: Re: bug#32485: 27.0.50; Problem with zerop on 32-bit platforms Date: Tue, 21 Aug 2018 13:54:11 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1

vc-hg-state-fast might still need attention. Currently (zerop (lsh -1 32)) returns nil on all platforms, so it's useless; but that might change

This prompted me to audit the uses of lsh in the Emacs source code. I found and fixed a few glitches by installing the attached patch; in particular it fixes vg-hg-state-fast by using ash instead, as ash's semantics are clear and not subject to change. This patch goes further in this direction by replacing lsh with ash when either will do.

As this fixes the remaining problems mentioned in this bug report, I'm boldly closing the report.

0001-Audit-use-of-lsh-and-fix-glitches.patch
Description: Text Data

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