[GiNaC-devel] chinese_remainder() bug versus x86_64 (Was: Univariate GCD benchmark)

[Alexei Sheplyakov]

Dear Richard,

Some time ago I wrote:

> I've got another theory. There was a bug in chinese_remainder() function.
> It's easy to spot it on 32-bit architecture, but not on 64-bit one. If my
> theory is correct, the patch below should trigger the bug on 64-bit
> architecture. Could you please try it (WITHOUT applying a patch which is
> supposed to fix the bug, of course)?
> 
> 
> Note: this patch is not supposed to be applied to the `official' repository.
> 
> diff --git a/ginac/polynomial/primes_factory.h b/ginac/polynomial/primes_factory.h
> index 093c973..d80bff7 100644
> --- a/ginac/polynomial/primes_factory.h
> +++ b/ginac/polynomial/primes_factory.h
> @@ -25,7 +25,7 @@ private:
>         cln::cl_I last;
>         // This ensures coefficients are immediate.
>         static const int immediate_bits = 8*sizeof(void *) - __alignof__(void *);
> -       static const long opt_hint = (1L << (immediate_bits >> 1)) - 1;
> +       static const long opt_hint = (1L << 14) - 1L;
>  public:
>         primes_factory()
>         {

Any feedback? I'm sorry for hurrying you, but this issue needs to be clarified
before the release.

Best regards,
	Alexei

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