[Octave-bug-tracker] [bug #49667] Computing powers of complex numbers in 4.2.0 is slower than in 4.0.3

[Mike Miller]

Follow-up Comment #3, bug #49667 (project octave):

Avinoam - I think it's pretty clear this is related to the older toolchain on
Ubuntu 14.04 / Mint 17, but thanks for confirming anyway.

Related: http://stackoverflow.com/q/5627030/384593, bug #38142

Compare the definition of std::pow(std::complex<double>, int) in gcc 4.8.4
(the version in Ubuntu 14.04)

https://github.com/gcc-mirror/gcc/blob/gcc-4_8_4-release/libstdc%2B%2B-v3/include/std/complex#L975

with the same function in gcc 5 / 6

https://github.com/gcc-mirror/gcc/blob/gcc-5_1_0-release/libstdc%2B%2B-v3/include/std/complex#L976

So yes, I would say that this performance degradation is a defect in gcc 4.8
running in C++11 mode.

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