https://gcc.gnu.org/bugzilla/show_bug.cgi?id=32503
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed|2007-06-26 10:47:05 |2019-6-3
Blocks| |53947
Summary|__builtin_powi - optimize |__builtin_pow[i] -
|for other exponents besides |vectorize for other
|2 and 0.5 |exponents besides 2 and 0.5
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Eric Gallager from comment #4)
> (In reply to Richard Biener from comment #2)
> > Confirmed. I had done tree-level expansion of powi into add/mul sequences
> > at
> > one time. But this had been rejected for some reason I cannot remember
> > right now.
>
> Do you at least remember when that time was, so we can know where to go
> looking in the archives?
See the followup comment. We now do this expansion but it is too late
for vectorization. The vectorizer knows how to handle pow of a
constant via exp[2] which have vectorized variants. It also knows
square-root and square but doesn't try anything more fancy. See
vect_recog_pow_pattern.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations
