1 /* Lower and optimize address expressions.
2 Copyright (C) 2015-2018 Free Software Foundation, Inc.
3 Contributed by Marek Polacek <polacek@redhat.com>
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 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 #include "config.h"
22 #include "system.h"
23 #include "coretypes.h"
24 #include "alias.h"
25 #include "predict.h"
26 #include "tm.h"
27 #include "function.h"
28 #include "dominance.h"
29 #include "cfg.h"
30 #include "basic-block.h"
31 #include "tree-ssa-alias.h"
32 #include "symtab.h"
33 #include "tree.h"
34 #include "stringpool.h"
35 #include "tree-vrp.h"
36 #include "tree-ssanames.h"
37 #include "fold-const.h"
38 #include "gimple-expr.h"
39 #include "gimple.h"
40 #include "gimplify.h"
41 #include "gimple-iterator.h"
42 #include "gimplify-me.h"
43 #include "tree-pass.h"
44
45
46 namespace {
47
48 const pass_data pass_data_laddress =
49 {
50 GIMPLE_PASS, /* type */
51 "laddress", /* name */
52 OPTGROUP_NONE, /* optinfo_flags */
53 TV_GIMPLE_LADDRESS, /* tv_id */
54 ( PROP_cfg | PROP_ssa ), /* properties_required */
55 0, /* properties_provided */
56 0, /* properties_destroyed */
57 0, /* todo_flags_start */
58 0, /* todo_flags_finish */
59 };
60
61 class pass_laddress : public gimple_opt_pass
62 {
63 public:
pass_laddress(gcc::context * ctxt)64 pass_laddress (gcc::context *ctxt)
65 : gimple_opt_pass (pass_data_laddress, ctxt)
66 {}
67
68 /* opt_pass methods: */
clone()69 opt_pass * clone () { return new pass_laddress (m_ctxt); }
gate(function *)70 virtual bool gate (function *) { return optimize != 0; }
71 virtual unsigned int execute (function *);
72
73 }; // class pass_laddress
74
75 unsigned int
execute(function * fun)76 pass_laddress::execute (function *fun)
77 {
78 basic_block bb;
79
80 FOR_EACH_BB_FN (bb, fun)
81 {
82 for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
83 {
84 gimple *stmt = gsi_stmt (gsi);
85 if (!is_gimple_assign (stmt)
86 || gimple_assign_rhs_code (stmt) != ADDR_EXPR
87 || is_gimple_invariant_address (gimple_assign_rhs1 (stmt)))
88 {
89 gsi_next (&gsi);
90 continue;
91 }
92
93 /* Lower ADDR_EXPR assignments:
94 _4 = &b[i_9];
95 into
96 _1 = (sizetype) i_9;
97 _7 = _1 * 4;
98 _4 = &b + _7;
99 This ought to aid the vectorizer and expose CSE opportunities.
100 */
101
102 tree expr = gimple_assign_rhs1 (stmt);
103 poly_int64 bitsize, bitpos;
104 tree base, offset;
105 machine_mode mode;
106 int volatilep = 0, reversep, unsignedp = 0;
107 base = get_inner_reference (TREE_OPERAND (expr, 0), &bitsize,
108 &bitpos, &offset, &mode, &unsignedp,
109 &reversep, &volatilep);
110 gcc_assert (base != NULL_TREE);
111 poly_int64 bytepos = exact_div (bitpos, BITS_PER_UNIT);
112 if (offset != NULL_TREE)
113 {
114 if (maybe_ne (bytepos, 0))
115 offset = size_binop (PLUS_EXPR, offset, size_int (bytepos));
116 offset = force_gimple_operand_gsi (&gsi, offset, true, NULL,
117 true, GSI_SAME_STMT);
118 base = build_fold_addr_expr (base);
119 base = force_gimple_operand_gsi (&gsi, base, true, NULL,
120 true, GSI_SAME_STMT);
121 gimple *g = gimple_build_assign (gimple_assign_lhs (stmt),
122 POINTER_PLUS_EXPR, base, offset);
123 gsi_replace (&gsi, g, false);
124 }
125 gsi_next (&gsi);
126 }
127 }
128
129 return 0;
130 }
131
132 } // anon namespace
133
134 gimple_opt_pass *
make_pass_laddress(gcc::context * ctxt)135 make_pass_laddress (gcc::context *ctxt)
136 {
137 return new pass_laddress (ctxt);
138 }
139