CONFIG_IA64 is not available for thedefaultarchitecture x86.
Result is shown for architecture ia64

CONFIG_IA64 (not configurable)

configname: CONFIG_IA64

Linux Kernel Configuration
└─>Processor type and features
└─>IA64
In linux kernel since version 2.6.12  
The Itanium Processor Family is Intel's 64-bit successor to
the 32-bit X86 line. The IA-64 Linux project has a home
page at <http://www.linuxia64.org/> and a mailing list at
<linux-ia64@vger.kernel.org>.

selects
CONFIG_ARCH_BINFMT_ELF_EXTRA_PHDRS
CONFIG_ARCH_HAS_CPU_FINALIZE_INIT
CONFIG_ARCH_HAS_DMA_MARK_CLEAN
CONFIG_ARCH_HAS_STRNCPY_FROM_USER
CONFIG_ARCH_HAS_STRNLEN_USER
CONFIG_ARCH_MIGHT_HAVE_PC_PARPORT
CONFIG_ARCH_MIGHT_HAVE_PC_SERIO
CONFIG_ACPI
CONFIG_ACPI_NUMA
CONFIG_ARCH_ENABLE_MEMORY_HOTPLUG
CONFIG_ARCH_ENABLE_MEMORY_HOTREMOVE
CONFIG_ARCH_SUPPORTS_ACPI
CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT
CONFIG_ARCH_MIGHT_HAVE_ACPI_PDC
CONFIG_FORCE_PCI
CONFIG_PCI_DOMAINS
CONFIG_PCI_MSI
CONFIG_PCI_SYSCALL
CONFIG_HAVE_ASM_MODVERSIONS
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
CONFIG_HAVE_EXIT_THREAD
CONFIG_HAVE_KPROBES
CONFIG_HAVE_KRETPROBES
CONFIG_HAVE_FTRACE_MCOUNT_RECORD
CONFIG_HAVE_DYNAMIC_FTRACE
CONFIG_HAVE_FUNCTION_TRACER
CONFIG_HAVE_SETUP_PER_CPU_AREA
CONFIG_TTY
CONFIG_HAVE_ARCH_TRACEHOOK
CONFIG_HAVE_FUNCTION_DESCRIPTORS
CONFIG_HAVE_VIRT_CPU_ACCOUNTING
CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
CONFIG_GENERIC_IRQ_PROBE
CONFIG_GENERIC_PENDING_IRQ
CONFIG_GENERIC_IRQ_SHOW
CONFIG_GENERIC_IRQ_LEGACY
CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
CONFIG_GENERIC_IOMAP
CONFIG_GENERIC_SMP_IDLE_THREAD
CONFIG_ARCH_TASK_STRUCT_ON_STACK
CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
CONFIG_ARCH_THREAD_STACK_ALLOCATOR
CONFIG_ARCH_CLOCKSOURCE_DATA
CONFIG_GENERIC_TIME_VSYSCALL
CONFIG_LEGACY_TIMER_TICK
CONFIG_SWIOTLB
CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
CONFIG_HAVE_MOD_ARCH_SPECIFIC
CONFIG_MODULES_USE_ELF_RELA
CONFIG_ARCH_USE_CMPXCHG_LOCKREF
CONFIG_HAVE_ARCH_AUDITSYSCALL
CONFIG_NEED_DMA_MAP_STATE
CONFIG_NEED_SG_DMA_LENGTH
CONFIG_NUMA
CONFIG_PCI_MSI_ARCH_FALLBACKS
CONFIG_ZONE_DMA32