1 /* Shared code for before and after reload gcse implementations.
2 Copyright (C) 1997-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
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
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
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/>.
20 It is expected that more hunks of gcse.c and postreload-gcse.c should
21 migrate into this file. */
25 #include "coretypes.h"
31 #include "basic-block.h"
33 #include "gcse-common.h"
36 /* Record all of the canonicalized MEMs of record_last_mem_set_info's insn.
37 Note we store a pair of elements in the list, so they have to be
38 taken off pairwise. */
41 canon_list_insert (rtx dest, const_rtx x ATTRIBUTE_UNUSED, void *data)
47 while (GET_CODE (dest) == SUBREG
48 || GET_CODE (dest) == ZERO_EXTRACT
49 || GET_CODE (dest) == STRICT_LOW_PART)
50 dest = XEXP (dest, 0);
52 /* If DEST is not a MEM, then it will not conflict with a load. Note
53 that function calls are assumed to clobber memory, but are handled
59 dest_addr = get_addr (XEXP (dest, 0));
60 dest_addr = canon_rtx (dest_addr);
61 insn = ((struct gcse_note_stores_info *)data)->insn;
62 bb = BLOCK_FOR_INSN (insn)->index;
65 pair.dest_addr = dest_addr;
66 vec<modify_pair> *canon_mem_list
67 = ((struct gcse_note_stores_info *)data)->canon_mem_list;
68 canon_mem_list[bb].safe_push (pair);
71 /* Record memory modification information for INSN. We do not actually care
72 about the memory location(s) that are set, or even how they are set (consider
73 a CALL_INSN). We merely need to record which insns modify memory. */
76 record_last_mem_set_info_common (rtx_insn *insn,
77 vec<rtx_insn *> *modify_mem_list,
78 vec<modify_pair> *canon_modify_mem_list,
79 bitmap modify_mem_list_set,
80 bitmap blocks_with_calls)
85 bb = BLOCK_FOR_INSN (insn)->index;
86 modify_mem_list[bb].safe_push (insn);
87 bitmap_set_bit (modify_mem_list_set, bb);
90 bitmap_set_bit (blocks_with_calls, bb);
93 struct gcse_note_stores_info data;
95 data.canon_mem_list = canon_modify_mem_list;
96 note_stores (PATTERN (insn), canon_list_insert, (void*) &data);
101 /* For each block, compute whether X is transparent. X is either an
102 expression or an assignment [though we don't care which, for this context
103 an assignment is treated as an expression]. For each block where an
104 element of X is modified, reset the INDX bit in BMAP.
106 BLOCKS_WITH_CALLS indicates which blocks contain CALL_INSNs which kill
109 MODIFY_MEM_LIST_SET indicates which blocks have memory stores which might
110 kill a particular memory location.
112 CANON_MODIFY_MEM_LIST is the canonicalized list of memory locations modified
116 compute_transp (const_rtx x, int indx, sbitmap *bmap,
117 bitmap blocks_with_calls,
118 bitmap modify_mem_list_set,
119 vec<modify_pair> *canon_modify_mem_list)
125 /* repeat is used to turn tail-recursion into iteration since GCC
126 can't do it when there's no return value. */
138 for (def = DF_REG_DEF_CHAIN (REGNO (x));
140 def = DF_REF_NEXT_REG (def))
141 bitmap_clear_bit (bmap[DF_REF_BB (def)->index], indx);
147 if (! MEM_READONLY_P (x))
153 x_addr = get_addr (XEXP (x, 0));
154 x_addr = canon_rtx (x_addr);
156 /* First handle all the blocks with calls. We don't need to
157 do any list walking for them. */
158 EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
160 bitmap_clear_bit (bmap[bb_index], indx);
163 /* Now iterate over the blocks which have memory modifications
164 but which do not have any calls. */
165 EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
169 vec<modify_pair> list
170 = canon_modify_mem_list[bb_index];
174 FOR_EACH_VEC_ELT_REVERSE (list, ix, pair)
176 rtx dest = pair->dest;
177 rtx dest_addr = pair->dest_addr;
179 if (canon_true_dependence (dest, GET_MODE (dest),
180 dest_addr, x, x_addr))
182 bitmap_clear_bit (bmap[bb_index], indx);
206 for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
210 /* If we are about to do the last recursive call
211 needed at this level, change it into iteration.
212 This function is called enough to be worth it. */
219 compute_transp (XEXP (x, i), indx, bmap, blocks_with_calls,
220 modify_mem_list_set, canon_modify_mem_list);
222 else if (fmt[i] == 'E')
223 for (j = 0; j < XVECLEN (x, i); j++)
224 compute_transp (XVECEXP (x, i, j), indx, bmap, blocks_with_calls,
225 modify_mem_list_set, canon_modify_mem_list);