Tuning option issue in the clang-8 mtune=cortex-a57.cortex-a53'

Hi All,

I am compiling my soure code in ARM 64 bit compiler. I am seeing the below error when compiling code. I gone through the release document of gcc 4.9. it show it wiill support Initial big.LITTLE tuning support for the combination of Cortex-A57 and Cortex-A53 was added through the -mcpu=cortex-a57.cortex-a53

FYI:
http://sushihangover.github.io/gcc-4-dot-9-is-out-with-arm-enhancements/

Compiler :aarch64-cros-linux-gnu-clang -O2 -pipe -march=armv8-a+crc -mtune=cortex-a57.cortex-a53

GCC:./aarch64-cros-linux-gnu-gcc --version
aarch64-cros-linux-gnu-gcc.real (4.9.2_cos_gg_4.9.2-r201-ac6128e0a17a52f011797f33ac3e7d6273a9368d_4.9.2-r201) 4.9.x 20150123

clang-8: error: the clang compiler does not support ‘-mtune=cortex-a57.cortex-a53’

Is it support -mtune=cortex-a57.cortex-a53 clag-8. Could you help me how resolve this issue.

Thanks and Regards,
Venkat Pari