http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55016
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> 2012-10-23 06:12:30 UTC --- (In reply to comment #2) > For the application I have in mind a global flag will such as -ffaster-math > will not be suitable > as it would affect also places where full "single precision" is still > required. Flags can be used per function, but that doesn't work very well indeed. > I would like just to profit of the rcp and rsqrt instructions for cases where > their low "precision" is enough. Some math libraries (AIX for instance) provide a correctly rounded rsqrt, so it would have to be called vaguely_estimate_rsqrt or something (still not to be confused with the fast-math version that adds one refinement round to reach almost full precision).
