Daily bump.
[official-gcc.git] / gcc / inchash.c
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1 /* Incremential hashing for jhash.
2 Copyright (C) 2014-2015 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 #ifdef GENERATOR_FILE
21 #include "bconfig.h"
22 #else
23 #include "config.h"
24 #endif
25 #include "system.h"
26 #include "coretypes.h"
27 #include "hashtab.h"
28 #include "inchash.h"
30 /* Borrowed from hashtab.c iterative_hash implementation. */
31 #define mix(a,b,c) \
32 { \
33 a -= b; a -= c; a ^= (c>>13); \
34 b -= c; b -= a; b ^= (a<< 8); \
35 c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
36 a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
37 b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
38 c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
39 a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
40 b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
41 c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
45 /* Produce good hash value combining VAL and VAL2. */
46 hashval_t
47 iterative_hash_hashval_t (hashval_t val, hashval_t val2)
49 /* the golden ratio; an arbitrary value. */
50 hashval_t a = 0x9e3779b9;
52 mix (a, val, val2);
53 return val2;
56 /* Produce good hash value combining VAL and VAL2. */
58 hashval_t
59 iterative_hash_host_wide_int (HOST_WIDE_INT val, hashval_t val2)
61 if (sizeof (HOST_WIDE_INT) == sizeof (hashval_t))
62 return iterative_hash_hashval_t (val, val2);
63 else
65 hashval_t a = (hashval_t) val;
66 /* Avoid warnings about shifting of more than the width of the type on
67 hosts that won't execute this path. */
68 int zero = 0;
69 hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 8 + zero));
70 mix (a, b, val2);
71 if (sizeof (HOST_WIDE_INT) > 2 * sizeof (hashval_t))
73 hashval_t a = (hashval_t) (val >> (sizeof (hashval_t) * 16 + zero));
74 hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 24 + zero));
75 mix (a, b, val2);
77 return val2;