Re: RPM building (was regression on RedHat)

Thomas Lockhart writes:

> Mandrake (as of 7.2) still does a brain-dead mix of "-O3" and
> "-ffast-math", which is a risky and unnecessary combination according to
> the gcc folks (and which kills some of our date/time rounding). From the
> man page for gcc:
>
> -ffast-math
>  This  option  should never be turned on by any `-O' option
>  since it can result in incorrect output for programs which
>  depend on an exact implementation of IEEE  or  ANSI
>  rules/specifications for math functions.

You're reading this wrong.  What this means is:

"If you're working on GCC, do not ever think of enabling -ffast-math
implicitly by any -Ox level [since most other -fxxx options are grouped
under some -Ox], since programs that might want optimization could still
depend on correct IEEE math."

In particular, Mandrake is not wrong to compile with -O3 and -ffast-math.
The consequence would only be slightly incorrect math results, and that is
what indeed happened.

-- 
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/