An empty list is permitted. See clobbers-and-scratch-registers. {GotoLabels} When you are using the goto form of asm, this section contains the list of all C labels to which the code in the {AssemblerTemplate} may jump. See gotolabels. asm statements may not perform jumps into other ...
I suspect every case using those barriers needs to prevent memory reordering across the barrier, but at present either the function call is an extern function call (which implies a memory clobber)* or has an explicit memory clobber in the inline asm, which will prevent memory reordering around ...
SECTION 1 Contains a listing of all of the High Impact or Pervasive (HIPER) PTFs that are in this package. SECTION 2 Contains a listing of all of the other (non-HIPER) PTFs that are in this package. Within each section, each PTF that is included in this PTF Package is listed by ...