xref: /netbsd-src/external/gpl3/gcc.old/dist/gcc/config/avr/avr-passes.def (revision 154bfe8e089c1a0a4e9ed8414f08d3da90949162)
1/* Description of target passes for AVR.
2   Copyright (C) 2016-2018 Free Software Foundation, Inc. */
3
4/* This file is part of GCC.
5
6   GCC is free software; you can redistribute it and/or modify it under
7   the terms of the GNU General Public License as published by the Free
8   Software Foundation; either version 3, or (at your option) any later
9   version.
10
11   GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12   WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GCC; see the file COPYING3.  If not see
18   <http://www.gnu.org/licenses/>.  */
19
20/* An analysis pass that runs prior to prologue / epilogue generation.
21   Computes cfun->machine->gasisr.maybe which is used in prologue and
22   epilogue generation provided -mgas-isr-prologues is on.  */
23
24INSERT_PASS_BEFORE (pass_thread_prologue_and_epilogue, 1, avr_pass_pre_proep);
25
26/* This avr-specific pass (re)computes insn notes, in particular REG_DEAD
27   notes which are used by `avr.c::reg_unused_after' and branch offset
28   computations.  These notes must be correct, i.e. there must be no
29   dangling REG_DEAD notes; otherwise wrong code might result, cf. PR64331.
30
31   DF needs (correct) CFG, hence right before free_cfg is the last
32   opportunity to rectify notes.  */
33
34INSERT_PASS_BEFORE (pass_free_cfg, 1, avr_pass_recompute_notes);
35
36/* casesi uses a SImode switch index which is quite costly as most code will
37   work on HImode or QImode.  The following pass runs right after .expand and
38   tries to fix such situations by operating on the original mode.  This
39   reduces code size and register pressure.
40
41   The assertion is that the code generated by casesi is unaltered and a
42   a sign-extend or zero-extend from QImode or HImode precedes the casesi
43   insns withaout any insns in between.  */
44
45INSERT_PASS_AFTER (pass_expand, 1, avr_pass_casesi);
46