On 24/01/17 18:05, Adhemerval Zanella wrote:
On 03/01/2017 13:13, Wilco Dijkstra wrote:
+ /* If function uses stacked arguments save the old stack value so morestack
+ can return it. */
+ reg11 = gen_rtx_REG (Pmode, R11_REGNUM);
+ if (cfun->machine->frame.saved_regs_size
+ || cfun->machine->frame.saved_varargs_size)
+ emit_move_insn (reg11, stack_pointer_rtx);
This doesn't look right - we could have many arguments even without varargs or
saved regs. This would need to check varargs as well as ctrl->args.size (I
believe
that is the size of the arguments on the stack). It's fine to omit this
optimization
in the first version - we already emit 2-3 extra instructions for the check
anyway.
I will check for a better solution.
Hi Adhemerval
My only concern on this this patch is the initialization of R11 (internal arg
pointer). The current implementation looks to me is generating wrong code for a
testcase simply return the sum of ten int param, I see the function body is
using R11 while there is no initialization of it in split prologue, so if the
execution flow is *not* through __morestack, then R11 is not initialized.
As Wilco suggested, I feel using crtl->args.size instead of
cfun->machine->frame.saved_regs_size might be the correct approach after
checking assign_parms in function.c.
