I have removed the ANSI C standard violation where a pointer was decremented
in front of an array. As a bonus, it might have removed few pointer
operations per call depending of the input. I did these changes on top of
Jose Da Silva modifs that for some reasons have never been added to glibc.
(I have reviewed his changes and this is effectively an optimization). I
have not recompiled glibc but I have tested the changes outside the lib