https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58372
--- Comment #26 from Terry Guo <xuepeng.guo at intel dot com> ---
Hi Uroš:
I think I found why your proposed patch causes problem in Comment 23. It is all
about timing. The below code from patch is trying to set up DRAP reg in a
rather early stage when the function is not fully expanded to RTL.
+ if (crtl->drap_reg == NULL_RTX)
+ {
+ rtx drap_rtx = targetm.calls.get_drap_rtx ();
The targetm.calls.get_drap_rtx () will be hooked to ix86_get_drap_rtx () where
we will have code:
12046 drap_vreg = copy_to_reg (arg_ptr);
(gdb)
12047 seq = get_insns ();
(gdb)
12048 end_sequence ();
(gdb)
12050 insn = emit_insn_before (seq, NEXT_INSN (entry_of_function ()));
At this stage, what returned from (entry_of_function ()) is actually GIMPLE
form of the function, not the RTL form we are expecting. Then NEXT_INSN
(something_in_gimple) goes wrong.
