[Bug rtl-optimization/64164] [4.9/5/6 Regression] one more stack slot used due to one less inlining level

["aoliva at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64164

--- Comment #52 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Wed Aug 19 17:00:32 2015
New Revision: 227015

URL: https://gcc.gnu.org/viewcvs?rev=227015&root=gcc&view=rev
Log:
[PR64164] fix regressions reported on m68k and armeb

Defer stack slot address assignment for all parms that can't live in
pseudos, and accept pseudos assignments in assign_param_setup_block.

for  gcc/ChangeLog

        PR rtl-optimization/64164
        * cfgexpand.c (parm_maybe_byref_p): Renamed to...
        (parm_in_stack_slot_p): ... this.  Disregard mode, what
        matters is whether the parm will live in a pseudo or a stack
        slot.
        (expand_one_ssa_partition): Deal with params without a default
        def.  Disregard mode.
        * cfgexpand.h: Renamed function declaration.
        * tree-ssa-coalesce.c: Adjust.
        * function.c (split_complex_args): Allocate stack slot for
        unassigned parms before splitting.
        (parm_in_unassigned_mem_p): New.  Use it instead of
        parm_maybe_byref_p throughout this file.
        (assign_parm_setup_block): Use it.  Accept pseudos in the
        expand-assigned rtl.
        (assign_parm_setup_reg): Drop BLKmode requirement.
        (assign_parm_setup_stack): Allocate and fill in the address of
        unassigned MEM parms.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c
    trunk/gcc/cfgexpand.h
    trunk/gcc/function.c
    trunk/gcc/tree-ssa-coalesce.c