CONFIG_ARC_HAS_HW_MPY is not available for the default architecture x86.
Result is shown for architecture arc
default or selected kernelversion does not have config value CONFIG_ARC_HAS_HW_MPY.
Result is shown for kernelversion 4.4.99

Use Hardware Multiplier (Normal or Faster XMAC)


Linux Kernel Configuration
└─> ARC Architecture Configuration
└─> ARC CPU Configuration
└─> Use Hardware Multiplier (Normal or Faster XMAC)

Influences how gcc generates code for MPY operations.
If enabled, MPYxx insns are generated, provided by Standard/XMAC
Multipler. Otherwise software multipy lib is used