[Bug middle-end/47602] Permit inline asm to clobber PIC register

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602

--- Comment #7 from H.J. Lu <hjl.tools at gmail dot com> 2011-02-04 01:42:03 UTC ---
(In reply to comment #6)
>
> I can not find any discussion about fixing this issue in any way other than
> forbidding it.
> 

EBX is fixed in PIC. If it is changed in asm, it should be saved and
restored in asm. Otherwise, non-leaf functions may not work properly
even if it is saved/restored in prologue/epilogue.