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: 64 pass_laddress (gcc::context *ctxt) 65 : gimple_opt_pass (pass_data_laddress, ctxt) 66 {} 67 68 /* opt_pass methods: */ 69 opt_pass * clone () { return new pass_laddress (m_ctxt); } 70 virtual bool gate (function *) { return optimize != 0; } 71 virtual unsigned int execute (function *); 72 73 }; // class pass_laddress 74 75 unsigned int 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 * 135 make_pass_laddress (gcc::context *ctxt) 136 { 137 return new pass_laddress (ctxt); 138 } 139