[Bug target/55947] New: non constant memory models lose HLE qualifiers

["andi-gcc at firstfloor dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55947

             Bug #: 55947
           Summary: non constant memory models lose HLE qualifiers
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: andi-gcc@firstfloor.org


get_memmodel does this

 /* If the parameter is not a constant, it's a run time value so we'll just
     convert it to MEMMODEL_SEQ_CST to avoid annoying runtime checking.  */
  if (TREE_CODE (exp) != INTEGER_CST)
    return MEMMODEL_SEQ_CST;

This implies that if __ATOMIC_HLE_ACQUIRE, __ATOMIC_HLE_RELEASE are passed in
as non constant they will get lost.