[Bug libstdc++/43108] mixed complex<T> multiplication horribly inefficient

["paolo dot carlini at oracle dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from paolo dot carlini at oracle dot com  2010-02-17 21:43 -------
(In reply to comment #3)
> Well, but float * complex<float> isn't the same as complex<float> *
> complex<float>.  But the library (and also C promotion if you write
> that in literal C) presents us with complex<float> * complex<float>.

Where, exactly, the library presents complex * complex instead of complex *
float? I really don't see it. I see things like:

      complex<float>&
      operator*=(float __f)
      {
        _M_value *= __f;
        return *this;
      }

and I don't see where the library explicitly transforms __f to a complex, I see
something like complex = complex * float. But really, we have been through this
*already*, I'm absolutely sure, and I have zero problems with changing the
above, if Gaby agrees and you all are sure something changed since the lat
time, it's a 5 minutes work, but I'm still convinced that this is something
much more generally useful to optimize than the library.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43108