a hint that there has to be at least one iteration.

mix_pitch_and_residual()

find_spectral_pitch instead of using celt_rcp(celt_sqrt(x))

we're not going to use.

normalise_bands(). Also, another bunch of restrict qualifiers -- mainly
to tell the compiler there's no aliasing between the array bounds and the
data.

a division

first three bands (instead of total MDCT window energy)

the multiplications

remove unnecessary copying and some conditional branches.

X and Y.

to assume denominator is positive.

some calls to ec_enc_uint() by calls to ec_enc_bits() (saves divisions)

a use for that anymore now that the overlap can be less than one frame.

the more complex "n-best search" and replaced it with a greedy search

require a branch.

optimisations.

required) and using it in ec_{en|de}c_bits()

(and fix for celt_div with 16-bit numerator on a 16-bit CPU)