This patch adds the -march feature +pacbti to Armv8.1-M Mainline. This feature enables pointer signing and authentication instructions on M-class architectures. Pre-approved here . gcc/Changelog: * config/arm/arm.h (TARGET_HAVE_PACBTI): New macro. * config/arm/arm-cpus.in (pacbti): New feature. * doc/invoke.texi (Arm Options): Document it. Co-Authored-By: Tejas Belagod