http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54019
Oleg Endo <olegendo at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |kkojima at gcc dot gnu.org
--- Comment #1 from Oleg Endo <olegendo at gcc dot gnu.org> ---
In sh.c, above the function 'sh_function_ok_for_sibcall', which implements
TARGET_FUNCTION_OK_FOR_SIBCALL there is a comment:
/* If PIC, we cannot make sibling calls to global functions
because the PLT requires r12 to be live. */
PLT entries use r12 and expect it to be a valid GOT pointer.
Because r12 must be preserved across function calls, it will have to be
restored before doing the tail call, like
...
braf
mov.l @r15+,r12
If the PIC function was invoked by a non-PIC function, the contents of r12
might not be necessarily a valid GOT pointer.
Kaz, could you please confirm or refute this?
