http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59644
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |vmakarov at gcc dot gnu.org
--- Comment #22 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, supposedly the:
10432 /* If drap has been set, but it actually isn't live at the
start
10433 of the function and !stack_realign, there is no reason to
set it up. */
10434 if (crtl->drap_reg && !stack_realign)
10435 {
10436 basic_block bb = ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb;
10437 if (! REGNO_REG_SET_P (DF_LR_IN (bb), REGNO
(crtl->drap_reg)))
10438 {
10439 crtl->drap_reg = NULL_RTX;
10440 crtl->need_drap = false;
10441 }
10442 }
hunk needs to be performed somewhere else (at the start of ira function, or
during reload/LRA (reload_in_progress/lra_in_progress) or not at all.
Supposedly the second crtl->drap_reg = NULL_RTX hunk in that function is fine,
because that is done only if there are no %rsp/%rbp accesses in the function.
And the ix86_save_reg change would need guarding by some other flag (a bit in *
cfun->machine ?) that would be set when ix86_finalize_stack_realign_flags
performed the optimization (but couldn't clear drap_reg because it was needed,
but wasn't needed to be preserved).
