Re: test-float fails on ppc64 because DBL_MIN_EXP < LDBL_MIN_EXP

[Paolo Bonzini]

On 08/31/2011 05:48 PM, Jim Meyering wrote:
> The test-float test is failing on ppc64 with:
>
>      gcc version 4.4.4 20100630 (Red Hat 4.4.4-10) (GCC)
>      (albeit an aging Fedora 12 system)
>
> due to the failure of this assertion:
>
>      ASSERT (LDBL_MIN_EXP<= DBL_MIN_EXP);
>
> It fails because of these numbers:
>
>      $ :|gcc -dD -E -include stddef.h -|grep -E 'L?DBL_MIN_EXP'
>      #define __DBL_MIN_EXP__ (-1021)
>      #define __LDBL_MIN_EXP__ (-968)

It looks like the right test would be

ASSERT (LDBL_MIN_EXP - LDBL_MANT_DIG <= DBL_MIN_EXP - DBL_MANT_DIG);

This would be enough to assert that a double can be assigned to a long 
double.

Paolo