[ARM] Add command-line option for SB
SB (Speculative Barrier) is only mandatory from 8.5
onwards but is optional from Armv8.0-A. This patch adds a command
line option to enable SB, as it was previously only possible to
enable by selecting -march=armv8.5-a.
This patch also renames FeatureSpecRestrict to FeatureSB.
Reviewed By: olista01, LukeCheeseman
Differential Revision: https://reviews.llvm.org/D55990
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@350299 91177308-0d34-0410-b5e6-96231b3b80d8
15 files changed