1 /* Generic hooks for the RTL middle-end. 2 Copyright (C) 2004-2015 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 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "tm.h" 24 #include "rtl.h" 25 #include "rtlhooks-def.h" 26 #include "symtab.h" 27 #include "hashtab.h" 28 #include "hash-set.h" 29 #include "vec.h" 30 #include "machmode.h" 31 #include "hard-reg-set.h" 32 #include "input.h" 33 #include "function.h" 34 #include "flags.h" 35 #include "statistics.h" 36 #include "double-int.h" 37 #include "real.h" 38 #include "fixed-value.h" 39 #include "alias.h" 40 #include "wide-int.h" 41 #include "inchash.h" 42 #include "tree.h" 43 #include "insn-config.h" 44 #include "expmed.h" 45 #include "dojump.h" 46 #include "explow.h" 47 #include "calls.h" 48 #include "emit-rtl.h" 49 #include "varasm.h" 50 #include "stmt.h" 51 #include "expr.h" 52 #include "recog.h" 53 54 55 /* For speed, we will copy the RTX hooks struct member-by-member 56 instead of doing indirect calls. For these reason, we initialize 57 *two* struct rtl_hooks globals: rtl_hooks is the one that is used 58 to actually call the hooks, while general_rtl_hooks is used 59 to restore the hooks by passes that modify them. */ 60 61 const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER; 62 struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER; 63 64 rtx 65 gen_lowpart_general (machine_mode mode, rtx x) 66 { 67 rtx result = gen_lowpart_common (mode, x); 68 69 if (result) 70 return result; 71 /* Handle SUBREGs and hard REGs that were rejected by 72 simplify_gen_subreg. */ 73 else if (REG_P (x) || GET_CODE (x) == SUBREG) 74 { 75 result = gen_lowpart_common (mode, copy_to_reg (x)); 76 gcc_assert (result != 0); 77 return result; 78 } 79 else 80 { 81 int offset = 0; 82 83 /* The only additional case we can do is MEM. */ 84 gcc_assert (MEM_P (x)); 85 86 /* The following exposes the use of "x" to CSE. */ 87 if (GET_MODE_SIZE (GET_MODE (x)) <= UNITS_PER_WORD 88 && SCALAR_INT_MODE_P (GET_MODE (x)) 89 && TRULY_NOOP_TRUNCATION_MODES_P (mode, GET_MODE (x)) 90 && !reload_completed) 91 return gen_lowpart_general (mode, force_reg (GET_MODE (x), x)); 92 93 if (WORDS_BIG_ENDIAN) 94 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD) 95 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)); 96 97 if (BYTES_BIG_ENDIAN) 98 /* Adjust the address so that the address-after-the-data 99 is unchanged. */ 100 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)) 101 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))); 102 103 return adjust_address (x, mode, offset); 104 } 105 } 106 107 rtx 108 reg_num_sign_bit_copies_general (const_rtx x ATTRIBUTE_UNUSED, 109 machine_mode mode ATTRIBUTE_UNUSED, 110 const_rtx known_x ATTRIBUTE_UNUSED, 111 machine_mode known_mode ATTRIBUTE_UNUSED, 112 unsigned int known_ret ATTRIBUTE_UNUSED, 113 unsigned int *result ATTRIBUTE_UNUSED) 114 { 115 return NULL; 116 } 117 118 rtx 119 reg_nonzero_bits_general (const_rtx x ATTRIBUTE_UNUSED, 120 machine_mode mode ATTRIBUTE_UNUSED, 121 const_rtx known_x ATTRIBUTE_UNUSED, 122 machine_mode known_mode ATTRIBUTE_UNUSED, 123 unsigned HOST_WIDE_INT known_ret ATTRIBUTE_UNUSED, 124 unsigned HOST_WIDE_INT *nonzero ATTRIBUTE_UNUSED) 125 { 126 return NULL; 127 } 128 129 bool 130 reg_truncated_to_mode_general (machine_mode mode ATTRIBUTE_UNUSED, 131 const_rtx x ATTRIBUTE_UNUSED) 132 { 133 return false; 134 } 135 136 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point 137 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the 138 least-significant part of X. 139 MODE specifies how big a part of X to return. 140 141 If the requested operation cannot be done, 0 is returned. 142 143 This is similar to gen_lowpart_general. */ 144 145 rtx 146 gen_lowpart_if_possible (machine_mode mode, rtx x) 147 { 148 rtx result = gen_lowpart_common (mode, x); 149 150 if (result) 151 return result; 152 else if (MEM_P (x)) 153 { 154 /* This is the only other case we handle. */ 155 int offset = 0; 156 rtx new_rtx; 157 158 if (WORDS_BIG_ENDIAN) 159 offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD) 160 - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD)); 161 if (BYTES_BIG_ENDIAN) 162 /* Adjust the address so that the address-after-the-data is 163 unchanged. */ 164 offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)) 165 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))); 166 167 new_rtx = adjust_address_nv (x, mode, offset); 168 if (! memory_address_addr_space_p (mode, XEXP (new_rtx, 0), 169 MEM_ADDR_SPACE (x))) 170 return 0; 171 172 return new_rtx; 173 } 174 else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode 175 && validate_subreg (mode, GET_MODE (x), x, 176 subreg_lowpart_offset (mode, GET_MODE (x)))) 177 return gen_lowpart_SUBREG (mode, x); 178 else 179 return 0; 180 } 181 182