[patch,libfortran] PR31964 ishftc fails with certain thrid argument

[Toon Moene]

Jerry DeLisle wrote:

> Fortran defines bit shifting up to and including bit_size of a value.
> 
> It turns out that shifting is undefined for >= bit_size bits.

Ugh, I'm sorry this wasn't know (I know it for years, because of 
bringing g77 up to date with the various standards).

Fortran allows shifts up to the width of the item.

C allows shifts up to the width minus one of the time.

Hope this helps,

-- 
Toon Moene - e-mail: toon@moene.indiv.nluug.nl - phone: +31 346 214290
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