[Bug target/28896] -fstack-limit-symbol and m68k and non 68020

[baker at usgs dot gov]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28896

--- Comment #19 from Larry Baker <baker at usgs dot gov> 2012-08-25 00:28:56 UTC ---
I plan to start testing my patches on a ColdFire uClinux system on Monday.  In
the mean time, I am unsure whether my code is correct for the -fPIC
-mno-sep-data case.  I do not know if a5 is a volatile register, or if,
instead, it must be saved/restored.  It is possible (as shown by my example)
that a5 might otherwise not be needed by the code in a procedure.  In that
case, my code is not enabling the save/restore of a5, which would be wrong if
a5 is not volatile.  This is not a problem for -msep-data (implies -fPIC),
since a5 already has the correct value, and is not altered by my code.  I will
investigate whether a5 is volatile.  If anyone knows the answer already, please
add a comment.  If anyone can recommend what has to be called or modified to
force a5 to be saved/restored, I would appreciate hearing about that as well.

Thank you,

Larry Baker