Re: Integer wraparound bug with eval on OS X

[Eric Blake]

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According to Gary V. Vaughan on 4/30/2007 10:49 AM:
> Hi Eric,
> 
> I think your recent patch to eval has either broken something, or else
> tickled a long standing bug.  Using the latest gnulib and m4 HEAD, test
> 135 is failing.


> eval(-4 >> 65)
> -1
> eval(-4 >> 64)
> -1
> eval(-4 >> 63)
> -1

It looks like the failure is due to undefined C code (shifting by an
amount larger than the width of the type), and that the testsuite is just
tickling a long-standing bug.  branch-1_4 is immune because it
intentionally masks the shift amount to bring it back into width, so I
will have to port some of that code to HEAD.  Thanks for the heads-up on this.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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