Re: m4-1.4.9b on HP-UX 11

[Bruno Haible]

Albert Chin wrote:
> From the cc(1) man page:
>            +O[no]fltacc   Disable [enable] floating-point optimizations that
>                           can result in numerical differences.
> ...
> So, +Onofltacc disables floating-point optimizations.

I interpret this differently:

             +Ofltacc       Disable floating-point optimizations that
                            can result in numerical differences.
             +Onofltacc     enable floating-point optimizations that
                            can result in numerical differences.

This is consistent with the other parts of the doc, combined:

>                           +Ofltacc is the same as +Ofltacc=strict.
>                           +Onofltacc is the same as +Ofltacc=relaxed.
> ...
>  limited
>     Like default, but also allows floating
>     point optimizations which may affect the
>     generation and propagation of
>     infinities, NaNs, and the sign of zero.
> 
>  
>  relaxed
>     In addition to the optimizations allowed
>     by limited, permits optimizations, such
>     as reordering of expressions, even if
>     parenthesized, that may affect rounding
>     error.  This is the same as +Onofltacc.

Hence, "limited" and "relaxed" are not IEEE-754-safe optimizations.

Bruno