AMD K12

K12 was to be AMD's first custom microarchitecture based on the ARMv8-A (AArch64) instruction set with a planned release in 2017. Its predecessor, the Opteron A1100 series, also ARMv8-A, used ARM Cortex-A57 cores. the product still hasn't been released, with development of ARM architectures continuing but no products planned.
The microarchitecture was to focus on high frequency and power efficiency and will target the dense server, embedded and semi-custom market segments.