1 /* Generic hooks for the RTL middle-end. 2 Copyright (C) 2004-2018 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 #include "config.h" 21 #include "system.h" 22 #include "coretypes.h" 23 #include "tm.h" 24 #include "function.h" 25 #include "rtl.h" 26 #include "tree.h" 27 #include "insn-config.h" 28 #include "memmodel.h" 29 #include "emit-rtl.h" 30 #include "recog.h" 31 #include "rtlhooks-def.h" 32 #include "explow.h" 33 #include "target.h" 34 35 36 /* For speed, we will copy the RTX hooks struct member-by-member 37 instead of doing indirect calls. For these reason, we initialize 38 *two* struct rtl_hooks globals: rtl_hooks is the one that is used 39 to actually call the hooks, while general_rtl_hooks is used 40 to restore the hooks by passes that modify them. */ 41 42 const struct rtl_hooks general_rtl_hooks = RTL_HOOKS_INITIALIZER; 43 struct rtl_hooks rtl_hooks = RTL_HOOKS_INITIALIZER; 44 45 rtx 46 gen_lowpart_general (machine_mode mode, rtx x) 47 { 48 rtx result = gen_lowpart_common (mode, x); 49 50 if (result) 51 return result; 52 /* Handle SUBREGs and hard REGs that were rejected by 53 simplify_gen_subreg. */ 54 else if (REG_P (x) || GET_CODE (x) == SUBREG) 55 { 56 result = gen_lowpart_common (mode, copy_to_reg (x)); 57 gcc_assert (result != 0); 58 return result; 59 } 60 else 61 { 62 /* The only additional case we can do is MEM. */ 63 gcc_assert (MEM_P (x)); 64 65 /* The following exposes the use of "x" to CSE. */ 66 scalar_int_mode xmode; 67 if (is_a <scalar_int_mode> (GET_MODE (x), &xmode) 68 && GET_MODE_SIZE (xmode) <= UNITS_PER_WORD 69 && TRULY_NOOP_TRUNCATION_MODES_P (mode, xmode) 70 && !reload_completed) 71 return gen_lowpart_general (mode, force_reg (xmode, x)); 72 73 poly_int64 offset = byte_lowpart_offset (mode, GET_MODE (x)); 74 return adjust_address (x, mode, offset); 75 } 76 } 77 78 rtx 79 reg_num_sign_bit_copies_general (const_rtx, scalar_int_mode, scalar_int_mode, 80 unsigned int *) 81 { 82 return NULL; 83 } 84 85 rtx 86 reg_nonzero_bits_general (const_rtx, scalar_int_mode, scalar_int_mode, 87 unsigned HOST_WIDE_INT *) 88 { 89 return NULL; 90 } 91 92 bool 93 reg_truncated_to_mode_general (machine_mode mode ATTRIBUTE_UNUSED, 94 const_rtx x ATTRIBUTE_UNUSED) 95 { 96 return false; 97 } 98 99 /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a fixed-point 100 number, return an rtx (MEM, SUBREG, or CONST_INT) that refers to the 101 least-significant part of X. 102 MODE specifies how big a part of X to return. 103 104 If the requested operation cannot be done, 0 is returned. 105 106 This is similar to gen_lowpart_general. */ 107 108 rtx 109 gen_lowpart_if_possible (machine_mode mode, rtx x) 110 { 111 rtx result = gen_lowpart_common (mode, x); 112 113 if (result) 114 return result; 115 else if (MEM_P (x)) 116 { 117 /* This is the only other case we handle. */ 118 poly_int64 offset = byte_lowpart_offset (mode, GET_MODE (x)); 119 rtx new_rtx = adjust_address_nv (x, mode, offset); 120 if (! memory_address_addr_space_p (mode, XEXP (new_rtx, 0), 121 MEM_ADDR_SPACE (x))) 122 return 0; 123 124 return new_rtx; 125 } 126 else if (mode != GET_MODE (x) && GET_MODE (x) != VOIDmode && !SUBREG_P (x) 127 && validate_subreg (mode, GET_MODE (x), x, 128 subreg_lowpart_offset (mode, GET_MODE (x)))) 129 return gen_lowpart_SUBREG (mode, x); 130 else 131 return 0; 132 } 133 134