Complex division, compiler-rt and logarithm

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

Hi all,
the helper implementation of complex division in compiler-rt and libgcc
differ in one important aspect. compiler-rt is using prescaling to
reduce the precision loss due to cancellation effects. libgcc doesn't.
The down side to this approach is that it requires logb, fmax and scalbn
to work -- which are currently only in libm. I can see two different
approaches for this issue:
(1) Use the better algorithmic approach and provide a version of the
functions in question in libc.
(2) Use the simpler approach of libgcc.

Joerg