r8d 136 arch/x86/entry/calling.h xorl %r8d, %r8d /* nospec r8 */ r8d 89 arch/x86/include/asm/asm.h #define _ASM_ARG5L r8d r8d 45 arch/x86/include/asm/inst.h .ifc \r32,%r8d r8d 95 tools/perf/arch/x86/util/perf_regs.c SDT_NAME_REG(r8d, r8),