Better imitate the choice of which register to identify as ip for tilegx.
Better imitate the choice of which register to identify as ip
for tilegx.

libunwind/libunwind,djwatson/libunwind,frida/libunwind,vtjnash/libunwind,vtjnash/libunwind,djwatson/libunwind,yuyichao/libunwind,vtjnash/libunwind,rantala/libunwind,frida/libunwind,djwatson/libunwind,rantala/libunwind,libunwind/libunwind,yuyichao/libunwind,yuyichao/libunwind,libunwind/libunwind,rantala/libunwind,frida/libunwind