mini-gmp test suite could be improved

[Vincent Lefevre]

On 2018-09-05 17:43:29 +0200, Vincent Lefevre wrote:
> On 2018-09-05 16:00:18 +0200, Torbjorn Granlund wrote:
> > Perhaps this can be automated and given a new, trendy name now that
> > fuzzing has been on everybody's mind for so long? :-)
> 
> An interesting place is to check inequalities on integers, by adding
> or subtracting 1 on one side. And some magic constants. But it could
> also mean that there are several valid possibilities, and the language
> would need to be extended to handle that.

BTW, something I had done manually in MPFR:

2018-04-18 23:24:57 (rev 12619, vlefevre)

  [tests/tfma.c] Added test_underflow4. This allows to show that the
  bound MAX (MPFR_PREC (z), MPFR_PREC (s) + 1) in fma.c is optimal:
    * If one subtract 1 from the 1st term MPFR_PREC (z), a failure
      occurs in test_underflow4.
    * If one subtract 1 from the 2nd term MPFR_PREC (s) + 1, a failure
      occurs in test_underflow2.

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Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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