OP_REF           3752 ext/pcre/pcrelib/pcre_compile.c              *previous == OP_REF)
OP_REF           5113 ext/pcre/pcrelib/pcre_compile.c         *code++ = OP_REF;
OP_REF           1721 ext/pcre/pcrelib/pcre_exec.c     case OP_REF: