gcc/
[official-gcc.git] / gcc / gcse-common.c
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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
9 version.
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.
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. */
23 #include "config.h"
24 #include "system.h"
25 #include "coretypes.h"
26 #include "tm.h"
27 #include "rtl.h"
28 #include "predict.h"
29 #include "bitmap.h"
30 #include "basic-block.h"
31 #include "df.h"
32 #include "gcse-common.h"
35 /* Record all of the canonicalized MEMs of record_last_mem_set_info's insn.
36 Note we store a pair of elements in the list, so they have to be
37 taken off pairwise. */
39 void
40 canon_list_insert (rtx dest, const_rtx x ATTRIBUTE_UNUSED, void *data)
42 rtx dest_addr;
43 int bb;
44 modify_pair pair;
46 while (GET_CODE (dest) == SUBREG
47 || GET_CODE (dest) == ZERO_EXTRACT
48 || GET_CODE (dest) == STRICT_LOW_PART)
49 dest = XEXP (dest, 0);
51 /* If DEST is not a MEM, then it will not conflict with a load. Note
52 that function calls are assumed to clobber memory, but are handled
53 elsewhere. */
55 if (! MEM_P (dest))
56 return;
58 dest_addr = get_addr (XEXP (dest, 0));
59 dest_addr = canon_rtx (dest_addr);
60 rtx_insn *insn = ((struct gcse_note_stores_info *)data)->insn;
61 bb = BLOCK_FOR_INSN (insn)->index;
63 pair.dest = dest;
64 pair.dest_addr = dest_addr;
65 vec<modify_pair> *canon_mem_list
66 = ((struct gcse_note_stores_info *)data)->canon_mem_list;
67 canon_mem_list[bb].safe_push (pair);
70 /* Record memory modification information for INSN. We do not actually care
71 about the memory location(s) that are set, or even how they are set (consider
72 a CALL_INSN). We merely need to record which insns modify memory. */
74 void
75 record_last_mem_set_info_common (rtx_insn *insn,
76 vec<rtx_insn *> *modify_mem_list,
77 vec<modify_pair> *canon_modify_mem_list,
78 bitmap modify_mem_list_set,
79 bitmap blocks_with_calls)
82 int bb;
84 bb = BLOCK_FOR_INSN (insn)->index;
85 modify_mem_list[bb].safe_push (insn);
86 bitmap_set_bit (modify_mem_list_set, bb);
88 if (CALL_P (insn))
89 bitmap_set_bit (blocks_with_calls, bb);
90 else
92 struct gcse_note_stores_info data;
93 data.insn = insn;
94 data.canon_mem_list = canon_modify_mem_list;
95 note_stores (PATTERN (insn), canon_list_insert, (void*) &data);
100 /* For each block, compute whether X is transparent. X is either an
101 expression or an assignment [though we don't care which, for this context
102 an assignment is treated as an expression]. For each block where an
103 element of X is modified, reset the INDX bit in BMAP.
105 BLOCKS_WITH_CALLS indicates which blocks contain CALL_INSNs which kill
106 memory.
108 MODIFY_MEM_LIST_SET indicates which blocks have memory stores which might
109 kill a particular memory location.
111 CANON_MODIFY_MEM_LIST is the canonicalized list of memory locations modified
112 for each block. */
114 void
115 compute_transp (const_rtx x, int indx, sbitmap *bmap,
116 bitmap blocks_with_calls,
117 bitmap modify_mem_list_set,
118 vec<modify_pair> *canon_modify_mem_list)
120 int i, j;
121 enum rtx_code code;
122 const char *fmt;
124 /* repeat is used to turn tail-recursion into iteration since GCC
125 can't do it when there's no return value. */
126 repeat:
128 if (x == 0)
129 return;
131 code = GET_CODE (x);
132 switch (code)
134 case REG:
136 df_ref def;
137 for (def = DF_REG_DEF_CHAIN (REGNO (x));
138 def;
139 def = DF_REF_NEXT_REG (def))
140 bitmap_clear_bit (bmap[DF_REF_BB (def)->index], indx);
143 return;
145 case MEM:
146 if (! MEM_READONLY_P (x))
148 bitmap_iterator bi;
149 unsigned bb_index;
150 rtx x_addr;
152 x_addr = get_addr (XEXP (x, 0));
153 x_addr = canon_rtx (x_addr);
155 /* First handle all the blocks with calls. We don't need to
156 do any list walking for them. */
157 EXECUTE_IF_SET_IN_BITMAP (blocks_with_calls, 0, bb_index, bi)
159 bitmap_clear_bit (bmap[bb_index], indx);
162 /* Now iterate over the blocks which have memory modifications
163 but which do not have any calls. */
164 EXECUTE_IF_AND_COMPL_IN_BITMAP (modify_mem_list_set,
165 blocks_with_calls,
166 0, bb_index, bi)
168 vec<modify_pair> list
169 = canon_modify_mem_list[bb_index];
170 modify_pair *pair;
171 unsigned ix;
173 FOR_EACH_VEC_ELT_REVERSE (list, ix, pair)
175 rtx dest = pair->dest;
176 rtx dest_addr = pair->dest_addr;
178 if (canon_true_dependence (dest, GET_MODE (dest),
179 dest_addr, x, x_addr))
181 bitmap_clear_bit (bmap[bb_index], indx);
182 break;
188 x = XEXP (x, 0);
189 goto repeat;
191 case PC:
192 case CC0: /*FIXME*/
193 case CONST:
194 CASE_CONST_ANY:
195 case SYMBOL_REF:
196 case LABEL_REF:
197 case ADDR_VEC:
198 case ADDR_DIFF_VEC:
199 return;
201 default:
202 break;
205 for (i = GET_RTX_LENGTH (code) - 1, fmt = GET_RTX_FORMAT (code); i >= 0; i--)
207 if (fmt[i] == 'e')
209 /* If we are about to do the last recursive call
210 needed at this level, change it into iteration.
211 This function is called enough to be worth it. */
212 if (i == 0)
214 x = XEXP (x, i);
215 goto repeat;
218 compute_transp (XEXP (x, i), indx, bmap, blocks_with_calls,
219 modify_mem_list_set, canon_modify_mem_list);
221 else if (fmt[i] == 'E')
222 for (j = 0; j < XVECLEN (x, i); j++)
223 compute_transp (XVECEXP (x, i, j), indx, bmap, blocks_with_calls,
224 modify_mem_list_set, canon_modify_mem_list);