1 /* Mode switching cleanup pass for the EPIPHANY cpu.
2 Copyright (C) 2000-2020 Free Software Foundation, Inc.
3 Contributed by Embecosm on behalf of Adapteva, Inc.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
11
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #define IN_TARGET_CODE 1
22
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "backend.h"
27 #include "rtl.h"
28 #include "df.h"
29 #include "memmodel.h"
30 #include "tm_p.h"
31 #include "insn-config.h"
32 #include "emit-rtl.h"
33 #include "recog.h"
34 #include "cfgrtl.h"
35 #include "insn-attr-common.h"
36 #include "tree-pass.h"
37
38 namespace {
39
40 const pass_data pass_data_resolve_sw_modes =
41 {
42 RTL_PASS, /* type */
43 "resolve_sw_modes", /* name */
44 OPTGROUP_NONE, /* optinfo_flags */
45 TV_MODE_SWITCH, /* tv_id */
46 0, /* properties_required */
47 0, /* properties_provided */
48 0, /* properties_destroyed */
49 0, /* todo_flags_start */
50 TODO_df_finish, /* todo_flags_finish */
51 };
52
53 class pass_resolve_sw_modes : public rtl_opt_pass
54 {
55 public:
pass_resolve_sw_modes(gcc::context * ctxt)56 pass_resolve_sw_modes(gcc::context *ctxt)
57 : rtl_opt_pass(pass_data_resolve_sw_modes, ctxt)
58 {}
59
60 /* opt_pass methods: */
gate(function *)61 virtual bool gate (function *) { return optimize; }
62 virtual unsigned int execute (function *);
63
64 }; // class pass_resolve_sw_modes
65
66 /* Clean-up after mode switching:
67 Check for mode setting insns that have FP_MODE_ROUND_UNKNOWN.
68 If only one rounding mode is required, select that one.
69 Else we have to choose one to use in this mode setting insn and
70 insert new mode setting insns on the edges where the other mode
71 becomes unambigous. */
72
73 unsigned
execute(function * fun)74 pass_resolve_sw_modes::execute (function *fun)
75 {
76 basic_block bb;
77 rtx_insn *insn;
78 rtx src;
79 vec<basic_block> todo;
80 sbitmap pushed;
81 bool need_commit = false;
82 bool finalize_fp_sets = (MACHINE_FUNCTION (cfun)->unknown_mode_sets == 0);
83
84 todo.create (last_basic_block_for_fn (fun));
85 pushed = sbitmap_alloc (last_basic_block_for_fn (fun));
86 bitmap_clear (pushed);
87 if (!finalize_fp_sets)
88 {
89 df_note_add_problem ();
90 df_analyze ();
91 }
92 FOR_EACH_BB_FN (bb, fun)
93 FOR_BB_INSNS (bb, insn)
94 {
95 enum attr_fp_mode selected_mode;
96
97 if (!NONJUMP_INSN_P (insn)
98 || recog_memoized (insn) != CODE_FOR_set_fp_mode)
99 continue;
100 src = SET_SRC (XVECEXP (PATTERN (insn), 0, 0));
101 if (finalize_fp_sets)
102 {
103 SET_SRC (XVECEXP (PATTERN (insn), 0, 2)) = copy_rtx (src);
104 if (REG_P (src))
105 df_insn_rescan (insn);
106 continue;
107 }
108 if (REG_P (src)
109 || XINT (XVECEXP (XEXP (src, 0), 0, 0), 0) != FP_MODE_ROUND_UNKNOWN)
110 continue;
111 if (find_regno_note (insn, REG_UNUSED, FP_TRUNCATE_REGNUM))
112 selected_mode = FP_MODE_ROUND_NEAREST;
113 else if (find_regno_note (insn, REG_UNUSED, FP_NEAREST_REGNUM))
114 selected_mode = FP_MODE_ROUND_TRUNC;
115 else
116 {
117 /* We could get more fancy in the selection of the mode by
118 checking the total frequency of the affected edges. */
119 selected_mode = (enum attr_fp_mode) epiphany_normal_fp_rounding;
120
121 todo.quick_push (bb);
122 bitmap_set_bit (pushed, bb->index);
123 }
124 XVECEXP (XEXP (src, 0), 0, 0) = GEN_INT (selected_mode);
125 SET_SRC (XVECEXP (PATTERN (insn), 0, 1)) = copy_rtx (src);
126 SET_SRC (XVECEXP (PATTERN (insn), 0, 2)) = copy_rtx (src);
127 df_insn_rescan (insn);
128 }
129 while (todo.length ())
130 {
131 basic_block bb = todo.pop ();
132 int selected_reg, jilted_reg;
133 enum attr_fp_mode jilted_mode;
134 edge e;
135 edge_iterator ei;
136
137 bitmap_set_bit (pushed, bb->index);
138 bitmap_set_bit (pushed, bb->index);
139
140 if (epiphany_normal_fp_rounding == FP_MODE_ROUND_NEAREST)
141 {
142 selected_reg = FP_NEAREST_REGNUM;
143 jilted_reg = FP_TRUNCATE_REGNUM;
144 jilted_mode = FP_MODE_ROUND_TRUNC;
145 }
146 else
147 {
148 selected_reg = FP_TRUNCATE_REGNUM;
149 jilted_reg = FP_NEAREST_REGNUM;
150 jilted_mode = FP_MODE_ROUND_NEAREST;
151 }
152
153 FOR_EACH_EDGE (e, ei, bb->succs)
154 {
155 basic_block succ = e->dest;
156 rtx_insn *seq;
157
158 if (!REGNO_REG_SET_P (DF_LIVE_IN (succ), jilted_reg))
159 continue;
160 if (REGNO_REG_SET_P (DF_LIVE_IN (succ), selected_reg))
161 {
162 if (bitmap_bit_p (pushed, succ->index))
163 continue;
164 todo.quick_push (succ);
165 bitmap_set_bit (pushed, bb->index);
166 continue;
167 }
168 start_sequence ();
169 emit_set_fp_mode (EPIPHANY_MSW_ENTITY_ROUND_UNKNOWN,
170 jilted_mode, FP_MODE_NONE,
171 reg_class_contents[NO_REGS]);
172 seq = get_insns ();
173 end_sequence ();
174 need_commit = true;
175 insert_insn_on_edge (seq, e);
176 }
177 }
178 todo.release ();
179 sbitmap_free (pushed);
180 if (need_commit)
181 commit_edge_insertions ();
182 return 0;
183 }
184
185 } // anon namespace
186
187 rtl_opt_pass *
make_pass_resolve_sw_modes(gcc::context * ctxt)188 make_pass_resolve_sw_modes (gcc::context *ctxt)
189 {
190 return new pass_resolve_sw_modes (ctxt);
191 }
192