CONFIG_CPU_HAS_LASX is not available for thedefaultarchitecture x86.
Result is shown for architecture loongarch

Support for the Loongson Advanced SIMD Extension

configname: CONFIG_CPU_HAS_LASX

Linux Kernel Configuration
└─>Kernel type and options
└─>Support for the Loongson Advanced SIMD Extension
In linux kernel since version 6.5 (release Date: 2023-08-27)  
Loongson Advanced SIMD Extension (LASX) introduces 256 bit wide vector
registers and a set of SIMD instructions to operate on them. When this
option is enabled the kernel will support allocating & switching LASX
vector register contexts. If you know that your kernel will only be
running on CPUs which do not support LASX or that your userland will
not be making use of it then you may wish to say N here to reduce
the size & complexity of your kernel.

If unsure, say Y.