[Bug tree-optimization/46728] GCC does not generate fmadd for pow (x, 0.75)+y on powerpc

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46728

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
   Target Milestone|4.6.0                       |---
            Summary|[4.6 Regression] GCC no     |GCC does not generate fmadd
                   |longer generates fmadd for  |for pow (x, 0.75)+y on
                   |pow (x, 0.75)+y on powerpc  |powerpc
           Severity|normal                      |enhancement

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-02-08 13:44:51 UTC ---
I had patches for powi expansion I think 6 years ago but they were rejected
(fortunately I can now approve them myself).  We should expose most of this
lowering to the vectorizer as it can vectorize sqrt and multiplication series
while it cannot vectorize pow or powi in general (it tries for some special
cases via the sucky pattern recognition).

Not a regression, no compiler was released with the fancy pow (x, 0.75) + y
handling.