CONFIG_ARC_HAS_LL64 is not available for the default architecture x86.
Result is shown for architecture arc

Insn: 64bit LDD/STD

configname: CONFIG_ARC_HAS_LL64

Linux Kernel Configuration
└─> ARC Architecture Configuration
└─> ARC CPU Configuration
└─> Insn: 64bit LDD/STD

Enable gcc to generate 64-bit load/store instructions
ISA mandates even/odd registers to allow encoding of two
dest operands with 2 possible source operands.