https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102952
--- Comment #28 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by H.J. Lu <h...@gcc.gnu.org>: https://gcc.gnu.org/g:2196a681d7810ad8b227bf983f38ba716620545e commit r12-5377-g2196a681d7810ad8b227bf983f38ba716620545e Author: H.J. Lu <hjl.to...@gmail.com> Date: Wed Oct 27 06:27:15 2021 -0700 x86: Add -mindirect-branch-cs-prefix Add -mindirect-branch-cs-prefix to add CS prefix to call and jmp to indirect thunk with branch target in r8-r15 registers so that the call and jmp instruction length is 6 bytes to allow them to be replaced with "lfence; call *%r8-r15" or "lfence; jmp *%r8-r15" at run-time. gcc/ PR target/102952 * config/i386/i386.c (ix86_output_jmp_thunk_or_indirect): Emit CS prefix for -mindirect-branch-cs-prefix. (ix86_output_indirect_branch_via_reg): Likewise. * config/i386/i386.opt: Add -mindirect-branch-cs-prefix. * doc/invoke.texi: Document -mindirect-branch-cs-prefix. gcc/testsuite/ PR target/102952 * gcc.target/i386/indirect-thunk-cs-prefix-1.c: New test. * gcc.target/i386/indirect-thunk-cs-prefix-2.c: Likewise.
