Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-loop-prefetch.c @ 131:84e7813d76e9
gcc-8.2
| author | mir3636 |
|---|---|
| date | Thu, 25 Oct 2018 07:37:49 +0900 |
| parents | 04ced10e8804 |
| children | 1830386684a0 |
| rev | line source |
|---|---|
| 0 | 1 /* Array prefetching. |
| 131 | 2 Copyright (C) 2005-2018 Free Software Foundation, Inc. |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
3 |
| 0 | 4 This file is part of GCC. |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
5 |
| 0 | 6 GCC is free software; you can redistribute it and/or modify it |
| 7 under the terms of the GNU General Public License as published by the | |
| 8 Free Software Foundation; either version 3, or (at your option) any | |
| 9 later version. | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
10 |
| 0 | 11 GCC is distributed in the hope that it will be useful, but WITHOUT |
| 12 ANY 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. | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
15 |
| 0 | 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" | |
| 111 | 23 #include "backend.h" |
| 24 #include "target.h" | |
| 25 #include "rtl.h" | |
| 0 | 26 #include "tree.h" |
| 111 | 27 #include "gimple.h" |
| 28 #include "predict.h" | |
| 29 #include "tree-pass.h" | |
| 30 #include "gimple-ssa.h" | |
| 31 #include "optabs-query.h" | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
32 #include "tree-pretty-print.h" |
| 111 | 33 #include "fold-const.h" |
| 34 #include "stor-layout.h" | |
| 35 #include "gimplify.h" | |
| 36 #include "gimple-iterator.h" | |
| 37 #include "gimplify-me.h" | |
| 38 #include "tree-ssa-loop-ivopts.h" | |
| 39 #include "tree-ssa-loop-manip.h" | |
| 40 #include "tree-ssa-loop-niter.h" | |
| 41 #include "tree-ssa-loop.h" | |
| 42 #include "ssa.h" | |
| 43 #include "tree-into-ssa.h" | |
| 0 | 44 #include "cfgloop.h" |
| 45 #include "tree-scalar-evolution.h" | |
| 46 #include "params.h" | |
| 47 #include "langhooks.h" | |
| 48 #include "tree-inline.h" | |
| 49 #include "tree-data-ref.h" | |
| 111 | 50 #include "diagnostic-core.h" |
| 51 #include "dbgcnt.h" | |
| 0 | 52 |
| 53 /* This pass inserts prefetch instructions to optimize cache usage during | |
| 54 accesses to arrays in loops. It processes loops sequentially and: | |
| 55 | |
| 56 1) Gathers all memory references in the single loop. | |
| 57 2) For each of the references it decides when it is profitable to prefetch | |
| 58 it. To do it, we evaluate the reuse among the accesses, and determines | |
| 59 two values: PREFETCH_BEFORE (meaning that it only makes sense to do | |
| 60 prefetching in the first PREFETCH_BEFORE iterations of the loop) and | |
| 61 PREFETCH_MOD (meaning that it only makes sense to prefetch in the | |
| 62 iterations of the loop that are zero modulo PREFETCH_MOD). For example | |
| 63 (assuming cache line size is 64 bytes, char has size 1 byte and there | |
| 64 is no hardware sequential prefetch): | |
| 65 | |
| 66 char *a; | |
| 67 for (i = 0; i < max; i++) | |
| 68 { | |
| 69 a[255] = ...; (0) | |
| 70 a[i] = ...; (1) | |
| 71 a[i + 64] = ...; (2) | |
| 72 a[16*i] = ...; (3) | |
| 73 a[187*i] = ...; (4) | |
| 74 a[187*i + 50] = ...; (5) | |
| 75 } | |
| 76 | |
| 77 (0) obviously has PREFETCH_BEFORE 1 | |
| 78 (1) has PREFETCH_BEFORE 64, since (2) accesses the same memory | |
| 79 location 64 iterations before it, and PREFETCH_MOD 64 (since | |
| 80 it hits the same cache line otherwise). | |
| 81 (2) has PREFETCH_MOD 64 | |
| 82 (3) has PREFETCH_MOD 4 | |
| 83 (4) has PREFETCH_MOD 1. We do not set PREFETCH_BEFORE here, since | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
84 the cache line accessed by (5) is the same with probability only |
| 0 | 85 7/32. |
| 86 (5) has PREFETCH_MOD 1 as well. | |
| 87 | |
| 88 Additionally, we use data dependence analysis to determine for each | |
| 89 reference the distance till the first reuse; this information is used | |
| 90 to determine the temporality of the issued prefetch instruction. | |
| 91 | |
| 92 3) We determine how much ahead we need to prefetch. The number of | |
| 93 iterations needed is time to fetch / time spent in one iteration of | |
| 94 the loop. The problem is that we do not know either of these values, | |
| 95 so we just make a heuristic guess based on a magic (possibly) | |
| 96 target-specific constant and size of the loop. | |
| 97 | |
| 98 4) Determine which of the references we prefetch. We take into account | |
| 99 that there is a maximum number of simultaneous prefetches (provided | |
| 100 by machine description). We prefetch as many prefetches as possible | |
| 101 while still within this bound (starting with those with lowest | |
| 102 prefetch_mod, since they are responsible for most of the cache | |
| 103 misses). | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
104 |
| 0 | 105 5) We unroll and peel loops so that we are able to satisfy PREFETCH_MOD |
| 106 and PREFETCH_BEFORE requirements (within some bounds), and to avoid | |
| 107 prefetching nonaccessed memory. | |
| 108 TODO -- actually implement peeling. | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
109 |
| 0 | 110 6) We actually emit the prefetch instructions. ??? Perhaps emit the |
| 111 prefetch instructions with guards in cases where 5) was not sufficient | |
| 112 to satisfy the constraints? | |
| 113 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
114 A cost model is implemented to determine whether or not prefetching is |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
115 profitable for a given loop. The cost model has three heuristics: |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
116 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
117 1. Function trip_count_to_ahead_ratio_too_small_p implements a |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
118 heuristic that determines whether or not the loop has too few |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
119 iterations (compared to ahead). Prefetching is not likely to be |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
120 beneficial if the trip count to ahead ratio is below a certain |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
121 minimum. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
122 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
123 2. Function mem_ref_count_reasonable_p implements a heuristic that |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
124 determines whether the given loop has enough CPU ops that can be |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
125 overlapped with cache missing memory ops. If not, the loop |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
126 won't benefit from prefetching. In the implementation, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
127 prefetching is not considered beneficial if the ratio between |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
128 the instruction count and the mem ref count is below a certain |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
129 minimum. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
130 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
131 3. Function insn_to_prefetch_ratio_too_small_p implements a |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
132 heuristic that disables prefetching in a loop if the prefetching |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
133 cost is above a certain limit. The relative prefetching cost is |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
134 estimated by taking the ratio between the prefetch count and the |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
135 total intruction count (this models the I-cache cost). |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
136 |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
137 The limits used in these heuristics are defined as parameters with |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
138 reasonable default values. Machine-specific default values will be |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
139 added later. |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
140 |
| 0 | 141 Some other TODO: |
| 142 -- write and use more general reuse analysis (that could be also used | |
| 143 in other cache aimed loop optimizations) | |
| 144 -- make it behave sanely together with the prefetches given by user | |
| 145 (now we just ignore them; at the very least we should avoid | |
| 146 optimizing loops in that user put his own prefetches) | |
| 147 -- we assume cache line size alignment of arrays; this could be | |
| 148 improved. */ | |
| 149 | |
| 150 /* Magic constants follow. These should be replaced by machine specific | |
| 151 numbers. */ | |
| 152 | |
| 153 /* True if write can be prefetched by a read prefetch. */ | |
| 154 | |
| 155 #ifndef WRITE_CAN_USE_READ_PREFETCH | |
| 156 #define WRITE_CAN_USE_READ_PREFETCH 1 | |
| 157 #endif | |
| 158 | |
| 159 /* True if read can be prefetched by a write prefetch. */ | |
| 160 | |
| 161 #ifndef READ_CAN_USE_WRITE_PREFETCH | |
| 162 #define READ_CAN_USE_WRITE_PREFETCH 0 | |
| 163 #endif | |
| 164 | |
| 165 /* The size of the block loaded by a single prefetch. Usually, this is | |
| 166 the same as cache line size (at the moment, we only consider one level | |
| 167 of cache hierarchy). */ | |
| 168 | |
| 169 #ifndef PREFETCH_BLOCK | |
| 170 #define PREFETCH_BLOCK L1_CACHE_LINE_SIZE | |
| 171 #endif | |
| 172 | |
| 173 /* Do we have a forward hardware sequential prefetching? */ | |
| 174 | |
| 175 #ifndef HAVE_FORWARD_PREFETCH | |
| 176 #define HAVE_FORWARD_PREFETCH 0 | |
| 177 #endif | |
| 178 | |
| 179 /* Do we have a backward hardware sequential prefetching? */ | |
| 180 | |
| 181 #ifndef HAVE_BACKWARD_PREFETCH | |
| 182 #define HAVE_BACKWARD_PREFETCH 0 | |
| 183 #endif | |
| 184 | |
| 185 /* In some cases we are only able to determine that there is a certain | |
| 186 probability that the two accesses hit the same cache line. In this | |
| 187 case, we issue the prefetches for both of them if this probability | |
| 188 is less then (1000 - ACCEPTABLE_MISS_RATE) per thousand. */ | |
| 189 | |
| 190 #ifndef ACCEPTABLE_MISS_RATE | |
| 191 #define ACCEPTABLE_MISS_RATE 50 | |
| 192 #endif | |
| 193 | |
| 194 #define L1_CACHE_SIZE_BYTES ((unsigned) (L1_CACHE_SIZE * 1024)) | |
| 195 #define L2_CACHE_SIZE_BYTES ((unsigned) (L2_CACHE_SIZE * 1024)) | |
| 196 | |
| 197 /* We consider a memory access nontemporal if it is not reused sooner than | |
| 198 after L2_CACHE_SIZE_BYTES of memory are accessed. However, we ignore | |
| 199 accesses closer than L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION, | |
| 200 so that we use nontemporal prefetches e.g. if single memory location | |
| 201 is accessed several times in a single iteration of the loop. */ | |
| 202 #define NONTEMPORAL_FRACTION 16 | |
| 203 | |
| 204 /* In case we have to emit a memory fence instruction after the loop that | |
| 205 uses nontemporal stores, this defines the builtin to use. */ | |
| 206 | |
| 207 #ifndef FENCE_FOLLOWING_MOVNT | |
| 208 #define FENCE_FOLLOWING_MOVNT NULL_TREE | |
| 209 #endif | |
| 210 | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
211 /* It is not profitable to prefetch when the trip count is not at |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
212 least TRIP_COUNT_TO_AHEAD_RATIO times the prefetch ahead distance. |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
213 For example, in a loop with a prefetch ahead distance of 10, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
214 supposing that TRIP_COUNT_TO_AHEAD_RATIO is equal to 4, it is |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
215 profitable to prefetch when the trip count is greater or equal to |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
216 40. In that case, 30 out of the 40 iterations will benefit from |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
217 prefetching. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
218 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
219 #ifndef TRIP_COUNT_TO_AHEAD_RATIO |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
220 #define TRIP_COUNT_TO_AHEAD_RATIO 4 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
221 #endif |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
222 |
| 0 | 223 /* The group of references between that reuse may occur. */ |
| 224 | |
| 225 struct mem_ref_group | |
| 226 { | |
| 227 tree base; /* Base of the reference. */ | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
228 tree step; /* Step of the reference. */ |
| 0 | 229 struct mem_ref *refs; /* References in the group. */ |
| 230 struct mem_ref_group *next; /* Next group of references. */ | |
| 111 | 231 unsigned int uid; /* Group UID, used only for debugging. */ |
| 0 | 232 }; |
| 233 | |
| 234 /* Assigned to PREFETCH_BEFORE when all iterations are to be prefetched. */ | |
| 235 | |
| 111 | 236 #define PREFETCH_ALL HOST_WIDE_INT_M1U |
| 0 | 237 |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
238 /* Do not generate a prefetch if the unroll factor is significantly less |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
239 than what is required by the prefetch. This is to avoid redundant |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
240 prefetches. For example, when prefetch_mod is 16 and unroll_factor is |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
241 2, prefetching requires unrolling the loop 16 times, but |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
242 the loop is actually unrolled twice. In this case (ratio = 8), |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
243 prefetching is not likely to be beneficial. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
244 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
245 #ifndef PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
246 #define PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO 4 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
247 #endif |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
248 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
249 /* Some of the prefetch computations have quadratic complexity. We want to |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
250 avoid huge compile times and, therefore, want to limit the amount of |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
251 memory references per loop where we consider prefetching. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
252 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
253 #ifndef PREFETCH_MAX_MEM_REFS_PER_LOOP |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
254 #define PREFETCH_MAX_MEM_REFS_PER_LOOP 200 |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
255 #endif |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
256 |
| 0 | 257 /* The memory reference. */ |
| 258 | |
| 259 struct mem_ref | |
| 260 { | |
| 111 | 261 gimple *stmt; /* Statement in that the reference appears. */ |
| 0 | 262 tree mem; /* The reference. */ |
| 263 HOST_WIDE_INT delta; /* Constant offset of the reference. */ | |
| 264 struct mem_ref_group *group; /* The group of references it belongs to. */ | |
| 265 unsigned HOST_WIDE_INT prefetch_mod; | |
| 266 /* Prefetch only each PREFETCH_MOD-th | |
| 267 iteration. */ | |
| 268 unsigned HOST_WIDE_INT prefetch_before; | |
| 269 /* Prefetch only first PREFETCH_BEFORE | |
| 270 iterations. */ | |
| 271 unsigned reuse_distance; /* The amount of data accessed before the first | |
| 272 reuse of this value. */ | |
| 273 struct mem_ref *next; /* The next reference in the group. */ | |
| 111 | 274 unsigned int uid; /* Ref UID, used only for debugging. */ |
| 0 | 275 unsigned write_p : 1; /* Is it a write? */ |
| 276 unsigned independent_p : 1; /* True if the reference is independent on | |
| 277 all other references inside the loop. */ | |
| 278 unsigned issue_prefetch_p : 1; /* Should we really issue the prefetch? */ | |
| 279 unsigned storent_p : 1; /* True if we changed the store to a | |
| 280 nontemporal one. */ | |
| 281 }; | |
| 282 | |
| 111 | 283 /* Dumps information about memory reference */ |
| 284 static void | |
| 285 dump_mem_details (FILE *file, tree base, tree step, | |
| 286 HOST_WIDE_INT delta, bool write_p) | |
| 287 { | |
| 288 fprintf (file, "(base "); | |
| 289 print_generic_expr (file, base, TDF_SLIM); | |
| 290 fprintf (file, ", step "); | |
| 291 if (cst_and_fits_in_hwi (step)) | |
| 292 fprintf (file, HOST_WIDE_INT_PRINT_DEC, int_cst_value (step)); | |
| 293 else | |
| 294 print_generic_expr (file, step, TDF_SLIM); | |
| 295 fprintf (file, ")\n"); | |
| 296 fprintf (file, " delta " HOST_WIDE_INT_PRINT_DEC "\n", delta); | |
| 297 fprintf (file, " %s\n\n", write_p ? "write" : "read"); | |
| 298 } | |
| 299 | |
| 0 | 300 /* Dumps information about reference REF to FILE. */ |
| 301 | |
| 302 static void | |
| 303 dump_mem_ref (FILE *file, struct mem_ref *ref) | |
| 304 { | |
| 111 | 305 fprintf (file, "reference %u:%u (", ref->group->uid, ref->uid); |
| 306 print_generic_expr (file, ref->mem, TDF_SLIM); | |
| 0 | 307 fprintf (file, ")\n"); |
| 308 } | |
| 309 | |
| 310 /* Finds a group with BASE and STEP in GROUPS, or creates one if it does not | |
| 311 exist. */ | |
| 312 | |
| 313 static struct mem_ref_group * | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
314 find_or_create_group (struct mem_ref_group **groups, tree base, tree step) |
| 0 | 315 { |
| 111 | 316 /* Global count for setting struct mem_ref_group->uid. */ |
| 317 static unsigned int last_mem_ref_group_uid = 0; | |
| 318 | |
| 0 | 319 struct mem_ref_group *group; |
| 320 | |
| 321 for (; *groups; groups = &(*groups)->next) | |
| 322 { | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
323 if (operand_equal_p ((*groups)->step, step, 0) |
| 0 | 324 && operand_equal_p ((*groups)->base, base, 0)) |
| 325 return *groups; | |
| 326 | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
327 /* If step is an integer constant, keep the list of groups sorted |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
328 by decreasing step. */ |
| 111 | 329 if (cst_and_fits_in_hwi ((*groups)->step) && cst_and_fits_in_hwi (step) |
| 330 && int_cst_value ((*groups)->step) < int_cst_value (step)) | |
| 0 | 331 break; |
| 332 } | |
| 333 | |
| 334 group = XNEW (struct mem_ref_group); | |
| 335 group->base = base; | |
| 336 group->step = step; | |
| 337 group->refs = NULL; | |
| 111 | 338 group->uid = ++last_mem_ref_group_uid; |
| 0 | 339 group->next = *groups; |
| 340 *groups = group; | |
| 341 | |
| 342 return group; | |
| 343 } | |
| 344 | |
| 345 /* Records a memory reference MEM in GROUP with offset DELTA and write status | |
| 346 WRITE_P. The reference occurs in statement STMT. */ | |
| 347 | |
| 348 static void | |
| 111 | 349 record_ref (struct mem_ref_group *group, gimple *stmt, tree mem, |
| 0 | 350 HOST_WIDE_INT delta, bool write_p) |
| 351 { | |
| 111 | 352 unsigned int last_mem_ref_uid = 0; |
| 0 | 353 struct mem_ref **aref; |
| 354 | |
| 355 /* Do not record the same address twice. */ | |
| 356 for (aref = &group->refs; *aref; aref = &(*aref)->next) | |
| 357 { | |
| 111 | 358 last_mem_ref_uid = (*aref)->uid; |
| 359 | |
| 0 | 360 /* It does not have to be possible for write reference to reuse the read |
| 361 prefetch, or vice versa. */ | |
| 362 if (!WRITE_CAN_USE_READ_PREFETCH | |
| 363 && write_p | |
| 364 && !(*aref)->write_p) | |
| 365 continue; | |
| 366 if (!READ_CAN_USE_WRITE_PREFETCH | |
| 367 && !write_p | |
| 368 && (*aref)->write_p) | |
| 369 continue; | |
| 370 | |
| 371 if ((*aref)->delta == delta) | |
| 372 return; | |
| 373 } | |
| 374 | |
| 375 (*aref) = XNEW (struct mem_ref); | |
| 376 (*aref)->stmt = stmt; | |
| 377 (*aref)->mem = mem; | |
| 378 (*aref)->delta = delta; | |
| 379 (*aref)->write_p = write_p; | |
| 380 (*aref)->prefetch_before = PREFETCH_ALL; | |
| 381 (*aref)->prefetch_mod = 1; | |
| 382 (*aref)->reuse_distance = 0; | |
| 383 (*aref)->issue_prefetch_p = false; | |
| 384 (*aref)->group = group; | |
| 385 (*aref)->next = NULL; | |
| 386 (*aref)->independent_p = false; | |
| 387 (*aref)->storent_p = false; | |
| 111 | 388 (*aref)->uid = last_mem_ref_uid + 1; |
| 0 | 389 |
| 390 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 111 | 391 { |
| 392 dump_mem_ref (dump_file, *aref); | |
| 393 | |
| 394 fprintf (dump_file, " group %u ", group->uid); | |
| 395 dump_mem_details (dump_file, group->base, group->step, delta, | |
| 396 write_p); | |
| 397 } | |
| 0 | 398 } |
| 399 | |
| 400 /* Release memory references in GROUPS. */ | |
| 401 | |
| 402 static void | |
| 403 release_mem_refs (struct mem_ref_group *groups) | |
| 404 { | |
| 405 struct mem_ref_group *next_g; | |
| 406 struct mem_ref *ref, *next_r; | |
| 407 | |
| 408 for (; groups; groups = next_g) | |
| 409 { | |
| 410 next_g = groups->next; | |
| 411 for (ref = groups->refs; ref; ref = next_r) | |
| 412 { | |
| 413 next_r = ref->next; | |
| 414 free (ref); | |
| 415 } | |
| 416 free (groups); | |
| 417 } | |
| 418 } | |
| 419 | |
| 420 /* A structure used to pass arguments to idx_analyze_ref. */ | |
| 421 | |
| 422 struct ar_data | |
| 423 { | |
| 424 struct loop *loop; /* Loop of the reference. */ | |
| 111 | 425 gimple *stmt; /* Statement of the reference. */ |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
426 tree *step; /* Step of the memory reference. */ |
| 0 | 427 HOST_WIDE_INT *delta; /* Offset of the memory reference. */ |
| 428 }; | |
| 429 | |
| 430 /* Analyzes a single INDEX of a memory reference to obtain information | |
| 431 described at analyze_ref. Callback for for_each_index. */ | |
| 432 | |
| 433 static bool | |
| 434 idx_analyze_ref (tree base, tree *index, void *data) | |
| 435 { | |
| 436 struct ar_data *ar_data = (struct ar_data *) data; | |
| 437 tree ibase, step, stepsize; | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
438 HOST_WIDE_INT idelta = 0, imult = 1; |
| 0 | 439 affine_iv iv; |
| 440 | |
| 441 if (!simple_iv (ar_data->loop, loop_containing_stmt (ar_data->stmt), | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
442 *index, &iv, true)) |
| 0 | 443 return false; |
| 444 ibase = iv.base; | |
| 445 step = iv.step; | |
| 446 | |
| 447 if (TREE_CODE (ibase) == POINTER_PLUS_EXPR | |
| 448 && cst_and_fits_in_hwi (TREE_OPERAND (ibase, 1))) | |
| 449 { | |
| 450 idelta = int_cst_value (TREE_OPERAND (ibase, 1)); | |
| 451 ibase = TREE_OPERAND (ibase, 0); | |
| 452 } | |
| 453 if (cst_and_fits_in_hwi (ibase)) | |
| 454 { | |
| 455 idelta += int_cst_value (ibase); | |
| 456 ibase = build_int_cst (TREE_TYPE (ibase), 0); | |
| 457 } | |
| 458 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
459 if (TREE_CODE (base) == ARRAY_REF) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
460 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
461 stepsize = array_ref_element_size (base); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
462 if (!cst_and_fits_in_hwi (stepsize)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
463 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
464 imult = int_cst_value (stepsize); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
465 step = fold_build2 (MULT_EXPR, sizetype, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
466 fold_convert (sizetype, step), |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
467 fold_convert (sizetype, stepsize)); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
468 idelta *= imult; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
469 } |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
470 |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
471 if (*ar_data->step == NULL_TREE) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
472 *ar_data->step = step; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
473 else |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
474 *ar_data->step = fold_build2 (PLUS_EXPR, sizetype, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
475 fold_convert (sizetype, *ar_data->step), |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
476 fold_convert (sizetype, step)); |
| 0 | 477 *ar_data->delta += idelta; |
| 478 *index = ibase; | |
| 479 | |
| 480 return true; | |
| 481 } | |
| 482 | |
| 483 /* Tries to express REF_P in shape &BASE + STEP * iter + DELTA, where DELTA and | |
| 484 STEP are integer constants and iter is number of iterations of LOOP. The | |
| 485 reference occurs in statement STMT. Strips nonaddressable component | |
| 486 references from REF_P. */ | |
| 487 | |
| 488 static bool | |
| 489 analyze_ref (struct loop *loop, tree *ref_p, tree *base, | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
490 tree *step, HOST_WIDE_INT *delta, |
| 111 | 491 gimple *stmt) |
| 0 | 492 { |
| 493 struct ar_data ar_data; | |
| 494 tree off; | |
| 495 HOST_WIDE_INT bit_offset; | |
| 496 tree ref = *ref_p; | |
| 497 | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
498 *step = NULL_TREE; |
| 0 | 499 *delta = 0; |
| 500 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
501 /* First strip off the component references. Ignore bitfields. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
502 Also strip off the real and imagine parts of a complex, so that |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
503 they can have the same base. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
504 if (TREE_CODE (ref) == REALPART_EXPR |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
505 || TREE_CODE (ref) == IMAGPART_EXPR |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
506 || (TREE_CODE (ref) == COMPONENT_REF |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
507 && DECL_NONADDRESSABLE_P (TREE_OPERAND (ref, 1)))) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
508 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
509 if (TREE_CODE (ref) == IMAGPART_EXPR) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
510 *delta += int_size_in_bytes (TREE_TYPE (ref)); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
511 ref = TREE_OPERAND (ref, 0); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
512 } |
| 0 | 513 |
| 514 *ref_p = ref; | |
| 515 | |
| 516 for (; TREE_CODE (ref) == COMPONENT_REF; ref = TREE_OPERAND (ref, 0)) | |
| 517 { | |
| 518 off = DECL_FIELD_BIT_OFFSET (TREE_OPERAND (ref, 1)); | |
| 519 bit_offset = TREE_INT_CST_LOW (off); | |
| 520 gcc_assert (bit_offset % BITS_PER_UNIT == 0); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
521 |
| 0 | 522 *delta += bit_offset / BITS_PER_UNIT; |
| 523 } | |
| 524 | |
| 525 *base = unshare_expr (ref); | |
| 526 ar_data.loop = loop; | |
| 527 ar_data.stmt = stmt; | |
| 528 ar_data.step = step; | |
| 529 ar_data.delta = delta; | |
| 530 return for_each_index (base, idx_analyze_ref, &ar_data); | |
| 531 } | |
| 532 | |
| 533 /* Record a memory reference REF to the list REFS. The reference occurs in | |
| 534 LOOP in statement STMT and it is write if WRITE_P. Returns true if the | |
| 535 reference was recorded, false otherwise. */ | |
| 536 | |
| 537 static bool | |
| 538 gather_memory_references_ref (struct loop *loop, struct mem_ref_group **refs, | |
| 111 | 539 tree ref, bool write_p, gimple *stmt) |
| 0 | 540 { |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
541 tree base, step; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
542 HOST_WIDE_INT delta; |
| 0 | 543 struct mem_ref_group *agrp; |
| 544 | |
| 545 if (get_base_address (ref) == NULL) | |
| 546 return false; | |
| 547 | |
| 548 if (!analyze_ref (loop, &ref, &base, &step, &delta, stmt)) | |
| 549 return false; | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
550 /* If analyze_ref fails the default is a NULL_TREE. We can stop here. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
551 if (step == NULL_TREE) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
552 return false; |
| 0 | 553 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
554 /* Stop if the address of BASE could not be taken. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
555 if (may_be_nonaddressable_p (base)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
556 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
557 |
| 111 | 558 /* Limit non-constant step prefetching only to the innermost loops and |
| 559 only when the step is loop invariant in the entire loop nest. */ | |
| 560 if (!cst_and_fits_in_hwi (step)) | |
| 561 { | |
| 562 if (loop->inner != NULL) | |
| 563 { | |
| 564 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 565 { | |
| 566 fprintf (dump_file, "Memory expression %p\n",(void *) ref ); | |
| 567 print_generic_expr (dump_file, ref, TDF_SLIM); | |
| 568 fprintf (dump_file,":"); | |
| 569 dump_mem_details (dump_file, base, step, delta, write_p); | |
| 570 fprintf (dump_file, | |
| 571 "Ignoring %p, non-constant step prefetching is " | |
| 572 "limited to inner most loops \n", | |
| 573 (void *) ref); | |
| 574 } | |
| 575 return false; | |
| 576 } | |
| 577 else | |
| 578 { | |
| 579 if (!expr_invariant_in_loop_p (loop_outermost (loop), step)) | |
| 580 { | |
| 581 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 582 { | |
| 583 fprintf (dump_file, "Memory expression %p\n",(void *) ref ); | |
| 584 print_generic_expr (dump_file, ref, TDF_SLIM); | |
| 585 fprintf (dump_file,":"); | |
| 586 dump_mem_details (dump_file, base, step, delta, write_p); | |
| 587 fprintf (dump_file, | |
| 588 "Not prefetching, ignoring %p due to " | |
| 589 "loop variant step\n", | |
| 590 (void *) ref); | |
| 591 } | |
| 592 return false; | |
| 593 } | |
| 594 } | |
| 595 } | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
596 |
| 0 | 597 /* Now we know that REF = &BASE + STEP * iter + DELTA, where DELTA and STEP |
| 598 are integer constants. */ | |
| 599 agrp = find_or_create_group (refs, base, step); | |
| 600 record_ref (agrp, stmt, ref, delta, write_p); | |
| 601 | |
| 602 return true; | |
| 603 } | |
| 604 | |
| 605 /* Record the suitable memory references in LOOP. NO_OTHER_REFS is set to | |
| 606 true if there are no other memory references inside the loop. */ | |
| 607 | |
| 608 static struct mem_ref_group * | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
609 gather_memory_references (struct loop *loop, bool *no_other_refs, unsigned *ref_count) |
| 0 | 610 { |
| 611 basic_block *body = get_loop_body_in_dom_order (loop); | |
| 612 basic_block bb; | |
| 613 unsigned i; | |
| 614 gimple_stmt_iterator bsi; | |
| 111 | 615 gimple *stmt; |
| 0 | 616 tree lhs, rhs; |
| 617 struct mem_ref_group *refs = NULL; | |
| 618 | |
| 619 *no_other_refs = true; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
620 *ref_count = 0; |
| 0 | 621 |
| 622 /* Scan the loop body in order, so that the former references precede the | |
| 623 later ones. */ | |
| 624 for (i = 0; i < loop->num_nodes; i++) | |
| 625 { | |
| 626 bb = body[i]; | |
| 627 if (bb->loop_father != loop) | |
| 628 continue; | |
| 629 | |
| 630 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) | |
| 631 { | |
| 632 stmt = gsi_stmt (bsi); | |
| 633 | |
| 634 if (gimple_code (stmt) != GIMPLE_ASSIGN) | |
| 635 { | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
636 if (gimple_vuse (stmt) |
| 0 | 637 || (is_gimple_call (stmt) |
| 638 && !(gimple_call_flags (stmt) & ECF_CONST))) | |
| 639 *no_other_refs = false; | |
| 640 continue; | |
| 641 } | |
| 642 | |
| 111 | 643 if (! gimple_vuse (stmt)) |
| 644 continue; | |
| 645 | |
| 0 | 646 lhs = gimple_assign_lhs (stmt); |
| 647 rhs = gimple_assign_rhs1 (stmt); | |
| 648 | |
| 649 if (REFERENCE_CLASS_P (rhs)) | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
650 { |
| 0 | 651 *no_other_refs &= gather_memory_references_ref (loop, &refs, |
| 652 rhs, false, stmt); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
653 *ref_count += 1; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
654 } |
| 0 | 655 if (REFERENCE_CLASS_P (lhs)) |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
656 { |
| 0 | 657 *no_other_refs &= gather_memory_references_ref (loop, &refs, |
| 658 lhs, true, stmt); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
659 *ref_count += 1; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
660 } |
| 0 | 661 } |
| 662 } | |
| 663 free (body); | |
| 664 | |
| 665 return refs; | |
| 666 } | |
| 667 | |
| 668 /* Prune the prefetch candidate REF using the self-reuse. */ | |
| 669 | |
| 670 static void | |
| 671 prune_ref_by_self_reuse (struct mem_ref *ref) | |
| 672 { | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
673 HOST_WIDE_INT step; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
674 bool backward; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
675 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
676 /* If the step size is non constant, we cannot calculate prefetch_mod. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
677 if (!cst_and_fits_in_hwi (ref->group->step)) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
678 return; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
679 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
680 step = int_cst_value (ref->group->step); |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
681 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
682 backward = step < 0; |
| 0 | 683 |
| 684 if (step == 0) | |
| 685 { | |
| 686 /* Prefetch references to invariant address just once. */ | |
| 687 ref->prefetch_before = 1; | |
| 688 return; | |
| 689 } | |
| 690 | |
| 691 if (backward) | |
| 692 step = -step; | |
| 693 | |
| 694 if (step > PREFETCH_BLOCK) | |
| 695 return; | |
| 696 | |
| 697 if ((backward && HAVE_BACKWARD_PREFETCH) | |
| 698 || (!backward && HAVE_FORWARD_PREFETCH)) | |
| 699 { | |
| 700 ref->prefetch_before = 1; | |
| 701 return; | |
| 702 } | |
| 703 | |
| 704 ref->prefetch_mod = PREFETCH_BLOCK / step; | |
| 705 } | |
| 706 | |
| 707 /* Divides X by BY, rounding down. */ | |
| 708 | |
| 709 static HOST_WIDE_INT | |
| 710 ddown (HOST_WIDE_INT x, unsigned HOST_WIDE_INT by) | |
| 711 { | |
| 712 gcc_assert (by > 0); | |
| 713 | |
| 714 if (x >= 0) | |
| 111 | 715 return x / (HOST_WIDE_INT) by; |
| 0 | 716 else |
| 111 | 717 return (x + (HOST_WIDE_INT) by - 1) / (HOST_WIDE_INT) by; |
| 0 | 718 } |
| 719 | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
720 /* Given a CACHE_LINE_SIZE and two inductive memory references |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
721 with a common STEP greater than CACHE_LINE_SIZE and an address |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
722 difference DELTA, compute the probability that they will fall |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
723 in different cache lines. Return true if the computed miss rate |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
724 is not greater than the ACCEPTABLE_MISS_RATE. DISTINCT_ITERS is the |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
725 number of distinct iterations after which the pattern repeats itself. |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
726 ALIGN_UNIT is the unit of alignment in bytes. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
727 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
728 static bool |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
729 is_miss_rate_acceptable (unsigned HOST_WIDE_INT cache_line_size, |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
730 HOST_WIDE_INT step, HOST_WIDE_INT delta, |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
731 unsigned HOST_WIDE_INT distinct_iters, |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
732 int align_unit) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
733 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
734 unsigned align, iter; |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
735 int total_positions, miss_positions, max_allowed_miss_positions; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
736 int address1, address2, cache_line1, cache_line2; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
737 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
738 /* It always misses if delta is greater than or equal to the cache |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
739 line size. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
740 if (delta >= (HOST_WIDE_INT) cache_line_size) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
741 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
742 |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
743 miss_positions = 0; |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
744 total_positions = (cache_line_size / align_unit) * distinct_iters; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
745 max_allowed_miss_positions = (ACCEPTABLE_MISS_RATE * total_positions) / 1000; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
746 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
747 /* Iterate through all possible alignments of the first |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
748 memory reference within its cache line. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
749 for (align = 0; align < cache_line_size; align += align_unit) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
750 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
751 /* Iterate through all distinct iterations. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
752 for (iter = 0; iter < distinct_iters; iter++) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
753 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
754 address1 = align + step * iter; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
755 address2 = address1 + delta; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
756 cache_line1 = address1 / cache_line_size; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
757 cache_line2 = address2 / cache_line_size; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
758 if (cache_line1 != cache_line2) |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
759 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
760 miss_positions += 1; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
761 if (miss_positions > max_allowed_miss_positions) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
762 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
763 } |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
764 } |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
765 return true; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
766 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
767 |
| 0 | 768 /* Prune the prefetch candidate REF using the reuse with BY. |
| 769 If BY_IS_BEFORE is true, BY is before REF in the loop. */ | |
| 770 | |
| 771 static void | |
| 772 prune_ref_by_group_reuse (struct mem_ref *ref, struct mem_ref *by, | |
| 773 bool by_is_before) | |
| 774 { | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
775 HOST_WIDE_INT step; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
776 bool backward; |
| 0 | 777 HOST_WIDE_INT delta_r = ref->delta, delta_b = by->delta; |
| 778 HOST_WIDE_INT delta = delta_b - delta_r; | |
| 779 HOST_WIDE_INT hit_from; | |
| 780 unsigned HOST_WIDE_INT prefetch_before, prefetch_block; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
781 HOST_WIDE_INT reduced_step; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
782 unsigned HOST_WIDE_INT reduced_prefetch_block; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
783 tree ref_type; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
784 int align_unit; |
| 0 | 785 |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
786 /* If the step is non constant we cannot calculate prefetch_before. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
787 if (!cst_and_fits_in_hwi (ref->group->step)) { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
788 return; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
789 } |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
790 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
791 step = int_cst_value (ref->group->step); |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
792 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
793 backward = step < 0; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
794 |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
795 |
| 0 | 796 if (delta == 0) |
| 797 { | |
| 798 /* If the references has the same address, only prefetch the | |
| 799 former. */ | |
| 800 if (by_is_before) | |
| 801 ref->prefetch_before = 0; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
802 |
| 0 | 803 return; |
| 804 } | |
| 805 | |
| 806 if (!step) | |
| 807 { | |
| 808 /* If the reference addresses are invariant and fall into the | |
| 809 same cache line, prefetch just the first one. */ | |
| 810 if (!by_is_before) | |
| 811 return; | |
| 812 | |
| 813 if (ddown (ref->delta, PREFETCH_BLOCK) | |
| 814 != ddown (by->delta, PREFETCH_BLOCK)) | |
| 815 return; | |
| 816 | |
| 817 ref->prefetch_before = 0; | |
| 818 return; | |
| 819 } | |
| 820 | |
| 821 /* Only prune the reference that is behind in the array. */ | |
| 822 if (backward) | |
| 823 { | |
| 824 if (delta > 0) | |
| 825 return; | |
| 826 | |
| 827 /* Transform the data so that we may assume that the accesses | |
| 828 are forward. */ | |
| 829 delta = - delta; | |
| 830 step = -step; | |
| 831 delta_r = PREFETCH_BLOCK - 1 - delta_r; | |
| 832 delta_b = PREFETCH_BLOCK - 1 - delta_b; | |
| 833 } | |
| 834 else | |
| 835 { | |
| 836 if (delta < 0) | |
| 837 return; | |
| 838 } | |
| 839 | |
| 840 /* Check whether the two references are likely to hit the same cache | |
| 841 line, and how distant the iterations in that it occurs are from | |
| 842 each other. */ | |
| 843 | |
| 844 if (step <= PREFETCH_BLOCK) | |
| 845 { | |
| 846 /* The accesses are sure to meet. Let us check when. */ | |
| 847 hit_from = ddown (delta_b, PREFETCH_BLOCK) * PREFETCH_BLOCK; | |
| 848 prefetch_before = (hit_from - delta_r + step - 1) / step; | |
| 849 | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
850 /* Do not reduce prefetch_before if we meet beyond cache size. */ |
| 111 | 851 if (prefetch_before > absu_hwi (L2_CACHE_SIZE_BYTES / step)) |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
852 prefetch_before = PREFETCH_ALL; |
| 0 | 853 if (prefetch_before < ref->prefetch_before) |
| 854 ref->prefetch_before = prefetch_before; | |
| 855 | |
| 856 return; | |
| 857 } | |
| 858 | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
859 /* A more complicated case with step > prefetch_block. First reduce |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
860 the ratio between the step and the cache line size to its simplest |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
861 terms. The resulting denominator will then represent the number of |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
862 distinct iterations after which each address will go back to its |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
863 initial location within the cache line. This computation assumes |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
864 that PREFETCH_BLOCK is a power of two. */ |
| 0 | 865 prefetch_block = PREFETCH_BLOCK; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
866 reduced_prefetch_block = prefetch_block; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
867 reduced_step = step; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
868 while ((reduced_step & 1) == 0 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
869 && reduced_prefetch_block > 1) |
| 0 | 870 { |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
871 reduced_step >>= 1; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
872 reduced_prefetch_block >>= 1; |
| 0 | 873 } |
| 874 | |
| 875 prefetch_before = delta / step; | |
| 876 delta %= step; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
877 ref_type = TREE_TYPE (ref->mem); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
878 align_unit = TYPE_ALIGN (ref_type) / 8; |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
879 if (is_miss_rate_acceptable (prefetch_block, step, delta, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
880 reduced_prefetch_block, align_unit)) |
| 0 | 881 { |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
882 /* Do not reduce prefetch_before if we meet beyond cache size. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
883 if (prefetch_before > L2_CACHE_SIZE_BYTES / PREFETCH_BLOCK) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
884 prefetch_before = PREFETCH_ALL; |
| 0 | 885 if (prefetch_before < ref->prefetch_before) |
| 886 ref->prefetch_before = prefetch_before; | |
| 887 | |
| 888 return; | |
| 889 } | |
| 890 | |
| 891 /* Try also the following iteration. */ | |
| 892 prefetch_before++; | |
| 893 delta = step - delta; | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
894 if (is_miss_rate_acceptable (prefetch_block, step, delta, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
895 reduced_prefetch_block, align_unit)) |
| 0 | 896 { |
| 897 if (prefetch_before < ref->prefetch_before) | |
| 898 ref->prefetch_before = prefetch_before; | |
| 899 | |
| 900 return; | |
| 901 } | |
| 902 | |
| 903 /* The ref probably does not reuse by. */ | |
| 904 return; | |
| 905 } | |
| 906 | |
| 907 /* Prune the prefetch candidate REF using the reuses with other references | |
| 908 in REFS. */ | |
| 909 | |
| 910 static void | |
| 911 prune_ref_by_reuse (struct mem_ref *ref, struct mem_ref *refs) | |
| 912 { | |
| 913 struct mem_ref *prune_by; | |
| 914 bool before = true; | |
| 915 | |
| 916 prune_ref_by_self_reuse (ref); | |
| 917 | |
| 918 for (prune_by = refs; prune_by; prune_by = prune_by->next) | |
| 919 { | |
| 920 if (prune_by == ref) | |
| 921 { | |
| 922 before = false; | |
| 923 continue; | |
| 924 } | |
| 925 | |
| 926 if (!WRITE_CAN_USE_READ_PREFETCH | |
| 927 && ref->write_p | |
| 928 && !prune_by->write_p) | |
| 929 continue; | |
| 930 if (!READ_CAN_USE_WRITE_PREFETCH | |
| 931 && !ref->write_p | |
| 932 && prune_by->write_p) | |
| 933 continue; | |
| 934 | |
| 935 prune_ref_by_group_reuse (ref, prune_by, before); | |
| 936 } | |
| 937 } | |
| 938 | |
| 939 /* Prune the prefetch candidates in GROUP using the reuse analysis. */ | |
| 940 | |
| 941 static void | |
| 942 prune_group_by_reuse (struct mem_ref_group *group) | |
| 943 { | |
| 944 struct mem_ref *ref_pruned; | |
| 945 | |
| 946 for (ref_pruned = group->refs; ref_pruned; ref_pruned = ref_pruned->next) | |
| 947 { | |
| 948 prune_ref_by_reuse (ref_pruned, group->refs); | |
| 949 | |
| 950 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 951 { | |
| 111 | 952 dump_mem_ref (dump_file, ref_pruned); |
| 0 | 953 |
| 954 if (ref_pruned->prefetch_before == PREFETCH_ALL | |
| 955 && ref_pruned->prefetch_mod == 1) | |
| 956 fprintf (dump_file, " no restrictions"); | |
| 957 else if (ref_pruned->prefetch_before == 0) | |
| 958 fprintf (dump_file, " do not prefetch"); | |
| 959 else if (ref_pruned->prefetch_before <= ref_pruned->prefetch_mod) | |
| 960 fprintf (dump_file, " prefetch once"); | |
| 961 else | |
| 962 { | |
| 963 if (ref_pruned->prefetch_before != PREFETCH_ALL) | |
| 964 { | |
| 965 fprintf (dump_file, " prefetch before "); | |
| 966 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, | |
| 967 ref_pruned->prefetch_before); | |
| 968 } | |
| 969 if (ref_pruned->prefetch_mod != 1) | |
| 970 { | |
| 971 fprintf (dump_file, " prefetch mod "); | |
| 972 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, | |
| 973 ref_pruned->prefetch_mod); | |
| 974 } | |
| 975 } | |
| 976 fprintf (dump_file, "\n"); | |
| 977 } | |
| 978 } | |
| 979 } | |
| 980 | |
| 981 /* Prune the list of prefetch candidates GROUPS using the reuse analysis. */ | |
| 982 | |
| 983 static void | |
| 984 prune_by_reuse (struct mem_ref_group *groups) | |
| 985 { | |
| 986 for (; groups; groups = groups->next) | |
| 987 prune_group_by_reuse (groups); | |
| 988 } | |
| 989 | |
| 990 /* Returns true if we should issue prefetch for REF. */ | |
| 991 | |
| 992 static bool | |
| 993 should_issue_prefetch_p (struct mem_ref *ref) | |
| 994 { | |
| 131 | 995 /* Do we want to issue prefetches for non-constant strides? */ |
| 996 if (!cst_and_fits_in_hwi (ref->group->step) && PREFETCH_DYNAMIC_STRIDES == 0) | |
| 997 { | |
| 998 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 999 fprintf (dump_file, | |
| 1000 "Skipping non-constant step for reference %u:%u\n", | |
| 1001 ref->group->uid, ref->uid); | |
| 1002 return false; | |
| 1003 } | |
| 1004 | |
| 1005 /* Some processors may have a hardware prefetcher that may conflict with | |
| 1006 prefetch hints for a range of strides. Make sure we don't issue | |
| 1007 prefetches for such cases if the stride is within this particular | |
| 1008 range. */ | |
| 1009 if (cst_and_fits_in_hwi (ref->group->step) | |
| 1010 && abs_hwi (int_cst_value (ref->group->step)) | |
| 1011 < (HOST_WIDE_INT) PREFETCH_MINIMUM_STRIDE) | |
| 1012 { | |
| 1013 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1014 fprintf (dump_file, | |
| 1015 "Step for reference %u:%u (" HOST_WIDE_INT_PRINT_DEC | |
| 1016 ") is less than the mininum required stride of %d\n", | |
| 1017 ref->group->uid, ref->uid, int_cst_value (ref->group->step), | |
| 1018 PREFETCH_MINIMUM_STRIDE); | |
| 1019 return false; | |
| 1020 } | |
| 1021 | |
| 0 | 1022 /* For now do not issue prefetches for only first few of the |
| 1023 iterations. */ | |
| 1024 if (ref->prefetch_before != PREFETCH_ALL) | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1025 { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1026 if (dump_file && (dump_flags & TDF_DETAILS)) |
| 111 | 1027 fprintf (dump_file, "Ignoring reference %u:%u due to prefetch_before\n", |
| 1028 ref->group->uid, ref->uid); | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1029 return false; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1030 } |
| 0 | 1031 |
| 1032 /* Do not prefetch nontemporal stores. */ | |
| 1033 if (ref->storent_p) | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1034 { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1035 if (dump_file && (dump_flags & TDF_DETAILS)) |
| 111 | 1036 fprintf (dump_file, "Ignoring nontemporal store reference %u:%u\n", ref->group->uid, ref->uid); |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1037 return false; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1038 } |
| 0 | 1039 |
| 1040 return true; | |
| 1041 } | |
| 1042 | |
| 1043 /* Decide which of the prefetch candidates in GROUPS to prefetch. | |
| 1044 AHEAD is the number of iterations to prefetch ahead (which corresponds | |
| 1045 to the number of simultaneous instances of one prefetch running at a | |
| 1046 time). UNROLL_FACTOR is the factor by that the loop is going to be | |
| 1047 unrolled. Returns true if there is anything to prefetch. */ | |
| 1048 | |
| 1049 static bool | |
| 1050 schedule_prefetches (struct mem_ref_group *groups, unsigned unroll_factor, | |
| 1051 unsigned ahead) | |
| 1052 { | |
| 1053 unsigned remaining_prefetch_slots, n_prefetches, prefetch_slots; | |
| 1054 unsigned slots_per_prefetch; | |
| 1055 struct mem_ref *ref; | |
| 1056 bool any = false; | |
| 1057 | |
| 1058 /* At most SIMULTANEOUS_PREFETCHES should be running at the same time. */ | |
| 1059 remaining_prefetch_slots = SIMULTANEOUS_PREFETCHES; | |
| 1060 | |
| 1061 /* The prefetch will run for AHEAD iterations of the original loop, i.e., | |
| 1062 AHEAD / UNROLL_FACTOR iterations of the unrolled loop. In each iteration, | |
| 1063 it will need a prefetch slot. */ | |
| 1064 slots_per_prefetch = (ahead + unroll_factor / 2) / unroll_factor; | |
| 1065 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1066 fprintf (dump_file, "Each prefetch instruction takes %u prefetch slots.\n", | |
| 1067 slots_per_prefetch); | |
| 1068 | |
| 1069 /* For now we just take memory references one by one and issue | |
| 1070 prefetches for as many as possible. The groups are sorted | |
| 1071 starting with the largest step, since the references with | |
| 1072 large step are more likely to cause many cache misses. */ | |
| 1073 | |
| 1074 for (; groups; groups = groups->next) | |
| 1075 for (ref = groups->refs; ref; ref = ref->next) | |
| 1076 { | |
| 1077 if (!should_issue_prefetch_p (ref)) | |
| 1078 continue; | |
| 1079 | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1080 /* The loop is far from being sufficiently unrolled for this |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1081 prefetch. Do not generate prefetch to avoid many redudant |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1082 prefetches. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1083 if (ref->prefetch_mod / unroll_factor > PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1084 continue; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1085 |
| 0 | 1086 /* If we need to prefetch the reference each PREFETCH_MOD iterations, |
| 1087 and we unroll the loop UNROLL_FACTOR times, we need to insert | |
| 1088 ceil (UNROLL_FACTOR / PREFETCH_MOD) instructions in each | |
| 1089 iteration. */ | |
| 1090 n_prefetches = ((unroll_factor + ref->prefetch_mod - 1) | |
| 1091 / ref->prefetch_mod); | |
| 1092 prefetch_slots = n_prefetches * slots_per_prefetch; | |
| 1093 | |
| 1094 /* If more than half of the prefetches would be lost anyway, do not | |
| 1095 issue the prefetch. */ | |
| 1096 if (2 * remaining_prefetch_slots < prefetch_slots) | |
| 1097 continue; | |
| 1098 | |
| 111 | 1099 /* Stop prefetching if debug counter is activated. */ |
| 1100 if (!dbg_cnt (prefetch)) | |
| 1101 continue; | |
| 1102 | |
| 0 | 1103 ref->issue_prefetch_p = true; |
| 111 | 1104 if (dump_file && (dump_flags & TDF_DETAILS)) |
| 1105 fprintf (dump_file, "Decided to issue prefetch for reference %u:%u\n", | |
| 1106 ref->group->uid, ref->uid); | |
| 0 | 1107 |
| 1108 if (remaining_prefetch_slots <= prefetch_slots) | |
| 1109 return true; | |
| 1110 remaining_prefetch_slots -= prefetch_slots; | |
| 1111 any = true; | |
| 1112 } | |
| 1113 | |
| 1114 return any; | |
| 1115 } | |
| 1116 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1117 /* Return TRUE if no prefetch is going to be generated in the given |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1118 GROUPS. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1119 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1120 static bool |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1121 nothing_to_prefetch_p (struct mem_ref_group *groups) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1122 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1123 struct mem_ref *ref; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1124 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1125 for (; groups; groups = groups->next) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1126 for (ref = groups->refs; ref; ref = ref->next) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1127 if (should_issue_prefetch_p (ref)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1128 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1129 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1130 return true; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1131 } |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1132 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1133 /* Estimate the number of prefetches in the given GROUPS. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1134 UNROLL_FACTOR is the factor by which LOOP was unrolled. */ |
| 0 | 1135 |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1136 static int |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1137 estimate_prefetch_count (struct mem_ref_group *groups, unsigned unroll_factor) |
| 0 | 1138 { |
| 1139 struct mem_ref *ref; | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1140 unsigned n_prefetches; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1141 int prefetch_count = 0; |
| 0 | 1142 |
| 1143 for (; groups; groups = groups->next) | |
| 1144 for (ref = groups->refs; ref; ref = ref->next) | |
| 1145 if (should_issue_prefetch_p (ref)) | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1146 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1147 n_prefetches = ((unroll_factor + ref->prefetch_mod - 1) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1148 / ref->prefetch_mod); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1149 prefetch_count += n_prefetches; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1150 } |
| 0 | 1151 |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1152 return prefetch_count; |
| 0 | 1153 } |
| 1154 | |
| 1155 /* Issue prefetches for the reference REF into loop as decided before. | |
| 1156 HEAD is the number of iterations to prefetch ahead. UNROLL_FACTOR | |
| 1157 is the factor by which LOOP was unrolled. */ | |
| 1158 | |
| 1159 static void | |
| 1160 issue_prefetch_ref (struct mem_ref *ref, unsigned unroll_factor, unsigned ahead) | |
| 1161 { | |
| 1162 HOST_WIDE_INT delta; | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1163 tree addr, addr_base, write_p, local, forward; |
| 111 | 1164 gcall *prefetch; |
| 0 | 1165 gimple_stmt_iterator bsi; |
| 1166 unsigned n_prefetches, ap; | |
| 1167 bool nontemporal = ref->reuse_distance >= L2_CACHE_SIZE_BYTES; | |
| 1168 | |
| 1169 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 111 | 1170 fprintf (dump_file, "Issued%s prefetch for reference %u:%u.\n", |
| 0 | 1171 nontemporal ? " nontemporal" : "", |
| 111 | 1172 ref->group->uid, ref->uid); |
| 0 | 1173 |
| 1174 bsi = gsi_for_stmt (ref->stmt); | |
| 1175 | |
| 1176 n_prefetches = ((unroll_factor + ref->prefetch_mod - 1) | |
| 1177 / ref->prefetch_mod); | |
| 1178 addr_base = build_fold_addr_expr_with_type (ref->mem, ptr_type_node); | |
| 1179 addr_base = force_gimple_operand_gsi (&bsi, unshare_expr (addr_base), | |
| 1180 true, NULL, true, GSI_SAME_STMT); | |
| 1181 write_p = ref->write_p ? integer_one_node : integer_zero_node; | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1182 local = nontemporal ? integer_zero_node : integer_three_node; |
| 0 | 1183 |
| 1184 for (ap = 0; ap < n_prefetches; ap++) | |
| 1185 { | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1186 if (cst_and_fits_in_hwi (ref->group->step)) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1187 { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1188 /* Determine the address to prefetch. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1189 delta = (ahead + ap * ref->prefetch_mod) * |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1190 int_cst_value (ref->group->step); |
| 111 | 1191 addr = fold_build_pointer_plus_hwi (addr_base, delta); |
| 1192 addr = force_gimple_operand_gsi (&bsi, unshare_expr (addr), true, | |
| 1193 NULL, true, GSI_SAME_STMT); | |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1194 } |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1195 else |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1196 { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1197 /* The step size is non-constant but loop-invariant. We use the |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1198 heuristic to simply prefetch ahead iterations ahead. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1199 forward = fold_build2 (MULT_EXPR, sizetype, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1200 fold_convert (sizetype, ref->group->step), |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1201 fold_convert (sizetype, size_int (ahead))); |
| 111 | 1202 addr = fold_build_pointer_plus (addr_base, forward); |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1203 addr = force_gimple_operand_gsi (&bsi, unshare_expr (addr), true, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1204 NULL, true, GSI_SAME_STMT); |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1205 } |
| 111 | 1206 |
| 1207 if (addr_base != addr | |
| 1208 && TREE_CODE (addr_base) == SSA_NAME | |
| 1209 && TREE_CODE (addr) == SSA_NAME) | |
| 1210 { | |
| 1211 duplicate_ssa_name_ptr_info (addr, SSA_NAME_PTR_INFO (addr_base)); | |
| 1212 /* As this isn't a plain copy we have to reset alignment | |
| 1213 information. */ | |
| 1214 if (SSA_NAME_PTR_INFO (addr)) | |
| 1215 mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (addr)); | |
| 1216 } | |
| 1217 | |
| 0 | 1218 /* Create the prefetch instruction. */ |
| 111 | 1219 prefetch = gimple_build_call (builtin_decl_explicit (BUILT_IN_PREFETCH), |
| 0 | 1220 3, addr, write_p, local); |
| 1221 gsi_insert_before (&bsi, prefetch, GSI_SAME_STMT); | |
| 1222 } | |
| 1223 } | |
| 1224 | |
| 1225 /* Issue prefetches for the references in GROUPS into loop as decided before. | |
| 1226 HEAD is the number of iterations to prefetch ahead. UNROLL_FACTOR is the | |
| 1227 factor by that LOOP was unrolled. */ | |
| 1228 | |
| 1229 static void | |
| 1230 issue_prefetches (struct mem_ref_group *groups, | |
| 1231 unsigned unroll_factor, unsigned ahead) | |
| 1232 { | |
| 1233 struct mem_ref *ref; | |
| 1234 | |
| 1235 for (; groups; groups = groups->next) | |
| 1236 for (ref = groups->refs; ref; ref = ref->next) | |
| 1237 if (ref->issue_prefetch_p) | |
| 1238 issue_prefetch_ref (ref, unroll_factor, ahead); | |
| 1239 } | |
| 1240 | |
| 1241 /* Returns true if REF is a memory write for that a nontemporal store insn | |
| 1242 can be used. */ | |
| 1243 | |
| 1244 static bool | |
| 1245 nontemporal_store_p (struct mem_ref *ref) | |
| 1246 { | |
| 111 | 1247 machine_mode mode; |
| 0 | 1248 enum insn_code code; |
| 1249 | |
| 1250 /* REF must be a write that is not reused. We require it to be independent | |
| 1251 on all other memory references in the loop, as the nontemporal stores may | |
| 1252 be reordered with respect to other memory references. */ | |
| 1253 if (!ref->write_p | |
| 1254 || !ref->independent_p | |
| 1255 || ref->reuse_distance < L2_CACHE_SIZE_BYTES) | |
| 1256 return false; | |
| 1257 | |
| 1258 /* Check that we have the storent instruction for the mode. */ | |
| 1259 mode = TYPE_MODE (TREE_TYPE (ref->mem)); | |
| 1260 if (mode == BLKmode) | |
| 1261 return false; | |
| 1262 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1263 code = optab_handler (storent_optab, mode); |
| 0 | 1264 return code != CODE_FOR_nothing; |
| 1265 } | |
| 1266 | |
| 1267 /* If REF is a nontemporal store, we mark the corresponding modify statement | |
| 1268 and return true. Otherwise, we return false. */ | |
| 1269 | |
| 1270 static bool | |
| 1271 mark_nontemporal_store (struct mem_ref *ref) | |
| 1272 { | |
| 1273 if (!nontemporal_store_p (ref)) | |
| 1274 return false; | |
| 1275 | |
| 1276 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 111 | 1277 fprintf (dump_file, "Marked reference %u:%u as a nontemporal store.\n", |
| 1278 ref->group->uid, ref->uid); | |
| 0 | 1279 |
| 1280 gimple_assign_set_nontemporal_move (ref->stmt, true); | |
| 1281 ref->storent_p = true; | |
| 1282 | |
| 1283 return true; | |
| 1284 } | |
| 1285 | |
| 1286 /* Issue a memory fence instruction after LOOP. */ | |
| 1287 | |
| 1288 static void | |
| 1289 emit_mfence_after_loop (struct loop *loop) | |
| 1290 { | |
| 111 | 1291 vec<edge> exits = get_loop_exit_edges (loop); |
| 0 | 1292 edge exit; |
| 111 | 1293 gcall *call; |
| 0 | 1294 gimple_stmt_iterator bsi; |
| 1295 unsigned i; | |
| 1296 | |
| 111 | 1297 FOR_EACH_VEC_ELT (exits, i, exit) |
| 0 | 1298 { |
| 1299 call = gimple_build_call (FENCE_FOLLOWING_MOVNT, 0); | |
| 1300 | |
| 1301 if (!single_pred_p (exit->dest) | |
| 1302 /* If possible, we prefer not to insert the fence on other paths | |
| 1303 in cfg. */ | |
| 1304 && !(exit->flags & EDGE_ABNORMAL)) | |
| 1305 split_loop_exit_edge (exit); | |
| 1306 bsi = gsi_after_labels (exit->dest); | |
| 1307 | |
| 1308 gsi_insert_before (&bsi, call, GSI_NEW_STMT); | |
| 1309 } | |
| 1310 | |
| 111 | 1311 exits.release (); |
| 0 | 1312 update_ssa (TODO_update_ssa_only_virtuals); |
| 1313 } | |
| 1314 | |
| 1315 /* Returns true if we can use storent in loop, false otherwise. */ | |
| 1316 | |
| 1317 static bool | |
| 1318 may_use_storent_in_loop_p (struct loop *loop) | |
| 1319 { | |
| 1320 bool ret = true; | |
| 1321 | |
| 1322 if (loop->inner != NULL) | |
| 1323 return false; | |
| 1324 | |
| 1325 /* If we must issue a mfence insn after using storent, check that there | |
| 1326 is a suitable place for it at each of the loop exits. */ | |
| 1327 if (FENCE_FOLLOWING_MOVNT != NULL_TREE) | |
| 1328 { | |
| 111 | 1329 vec<edge> exits = get_loop_exit_edges (loop); |
| 0 | 1330 unsigned i; |
| 1331 edge exit; | |
| 1332 | |
| 111 | 1333 FOR_EACH_VEC_ELT (exits, i, exit) |
| 0 | 1334 if ((exit->flags & EDGE_ABNORMAL) |
| 111 | 1335 && exit->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| 0 | 1336 ret = false; |
| 1337 | |
| 111 | 1338 exits.release (); |
| 0 | 1339 } |
| 1340 | |
| 1341 return ret; | |
| 1342 } | |
| 1343 | |
| 1344 /* Marks nontemporal stores in LOOP. GROUPS contains the description of memory | |
| 1345 references in the loop. */ | |
| 1346 | |
| 1347 static void | |
| 1348 mark_nontemporal_stores (struct loop *loop, struct mem_ref_group *groups) | |
| 1349 { | |
| 1350 struct mem_ref *ref; | |
| 1351 bool any = false; | |
| 1352 | |
| 1353 if (!may_use_storent_in_loop_p (loop)) | |
| 1354 return; | |
| 1355 | |
| 1356 for (; groups; groups = groups->next) | |
| 1357 for (ref = groups->refs; ref; ref = ref->next) | |
| 1358 any |= mark_nontemporal_store (ref); | |
| 1359 | |
| 1360 if (any && FENCE_FOLLOWING_MOVNT != NULL_TREE) | |
| 1361 emit_mfence_after_loop (loop); | |
| 1362 } | |
| 1363 | |
| 1364 /* Determines whether we can profitably unroll LOOP FACTOR times, and if | |
| 1365 this is the case, fill in DESC by the description of number of | |
| 1366 iterations. */ | |
| 1367 | |
| 1368 static bool | |
| 1369 should_unroll_loop_p (struct loop *loop, struct tree_niter_desc *desc, | |
| 1370 unsigned factor) | |
| 1371 { | |
| 1372 if (!can_unroll_loop_p (loop, factor, desc)) | |
| 1373 return false; | |
| 1374 | |
| 1375 /* We only consider loops without control flow for unrolling. This is not | |
| 1376 a hard restriction -- tree_unroll_loop works with arbitrary loops | |
| 1377 as well; but the unrolling/prefetching is usually more profitable for | |
| 1378 loops consisting of a single basic block, and we want to limit the | |
| 1379 code growth. */ | |
| 1380 if (loop->num_nodes > 2) | |
| 1381 return false; | |
| 1382 | |
| 1383 return true; | |
| 1384 } | |
| 1385 | |
| 1386 /* Determine the coefficient by that unroll LOOP, from the information | |
| 1387 contained in the list of memory references REFS. Description of | |
| 111 | 1388 number of iterations of LOOP is stored to DESC. NINSNS is the number of |
| 0 | 1389 insns of the LOOP. EST_NITER is the estimated number of iterations of |
| 1390 the loop, or -1 if no estimate is available. */ | |
| 1391 | |
| 1392 static unsigned | |
| 1393 determine_unroll_factor (struct loop *loop, struct mem_ref_group *refs, | |
| 1394 unsigned ninsns, struct tree_niter_desc *desc, | |
| 1395 HOST_WIDE_INT est_niter) | |
| 1396 { | |
| 1397 unsigned upper_bound; | |
| 1398 unsigned nfactor, factor, mod_constraint; | |
| 1399 struct mem_ref_group *agp; | |
| 1400 struct mem_ref *ref; | |
| 1401 | |
| 1402 /* First check whether the loop is not too large to unroll. We ignore | |
| 1403 PARAM_MAX_UNROLL_TIMES, because for small loops, it prevented us | |
| 1404 from unrolling them enough to make exactly one cache line covered by each | |
| 1405 iteration. Also, the goal of PARAM_MAX_UNROLL_TIMES is to prevent | |
| 1406 us from unrolling the loops too many times in cases where we only expect | |
| 1407 gains from better scheduling and decreasing loop overhead, which is not | |
| 1408 the case here. */ | |
| 1409 upper_bound = PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS) / ninsns; | |
| 1410 | |
| 1411 /* If we unrolled the loop more times than it iterates, the unrolled version | |
| 1412 of the loop would be never entered. */ | |
| 1413 if (est_niter >= 0 && est_niter < (HOST_WIDE_INT) upper_bound) | |
| 1414 upper_bound = est_niter; | |
| 1415 | |
| 1416 if (upper_bound <= 1) | |
| 1417 return 1; | |
| 1418 | |
| 1419 /* Choose the factor so that we may prefetch each cache just once, | |
| 1420 but bound the unrolling by UPPER_BOUND. */ | |
| 1421 factor = 1; | |
| 1422 for (agp = refs; agp; agp = agp->next) | |
| 1423 for (ref = agp->refs; ref; ref = ref->next) | |
| 1424 if (should_issue_prefetch_p (ref)) | |
| 1425 { | |
| 1426 mod_constraint = ref->prefetch_mod; | |
| 1427 nfactor = least_common_multiple (mod_constraint, factor); | |
| 1428 if (nfactor <= upper_bound) | |
| 1429 factor = nfactor; | |
| 1430 } | |
| 1431 | |
| 1432 if (!should_unroll_loop_p (loop, desc, factor)) | |
| 1433 return 1; | |
| 1434 | |
| 1435 return factor; | |
| 1436 } | |
| 1437 | |
| 1438 /* Returns the total volume of the memory references REFS, taking into account | |
| 1439 reuses in the innermost loop and cache line size. TODO -- we should also | |
| 1440 take into account reuses across the iterations of the loops in the loop | |
| 1441 nest. */ | |
| 1442 | |
| 1443 static unsigned | |
| 1444 volume_of_references (struct mem_ref_group *refs) | |
| 1445 { | |
| 1446 unsigned volume = 0; | |
| 1447 struct mem_ref_group *gr; | |
| 1448 struct mem_ref *ref; | |
| 1449 | |
| 1450 for (gr = refs; gr; gr = gr->next) | |
| 1451 for (ref = gr->refs; ref; ref = ref->next) | |
| 1452 { | |
| 1453 /* Almost always reuses another value? */ | |
| 1454 if (ref->prefetch_before != PREFETCH_ALL) | |
| 1455 continue; | |
| 1456 | |
| 1457 /* If several iterations access the same cache line, use the size of | |
| 1458 the line divided by this number. Otherwise, a cache line is | |
| 1459 accessed in each iteration. TODO -- in the latter case, we should | |
| 1460 take the size of the reference into account, rounding it up on cache | |
| 1461 line size multiple. */ | |
| 1462 volume += L1_CACHE_LINE_SIZE / ref->prefetch_mod; | |
| 1463 } | |
| 1464 return volume; | |
| 1465 } | |
| 1466 | |
| 1467 /* Returns the volume of memory references accessed across VEC iterations of | |
| 1468 loops, whose sizes are described in the LOOP_SIZES array. N is the number | |
| 1469 of the loops in the nest (length of VEC and LOOP_SIZES vectors). */ | |
| 1470 | |
| 1471 static unsigned | |
| 1472 volume_of_dist_vector (lambda_vector vec, unsigned *loop_sizes, unsigned n) | |
| 1473 { | |
| 1474 unsigned i; | |
| 1475 | |
| 1476 for (i = 0; i < n; i++) | |
| 1477 if (vec[i] != 0) | |
| 1478 break; | |
| 1479 | |
| 1480 if (i == n) | |
| 1481 return 0; | |
| 1482 | |
| 1483 gcc_assert (vec[i] > 0); | |
| 1484 | |
| 1485 /* We ignore the parts of the distance vector in subloops, since usually | |
| 1486 the numbers of iterations are much smaller. */ | |
| 1487 return loop_sizes[i] * vec[i]; | |
| 1488 } | |
| 1489 | |
| 1490 /* Add the steps of ACCESS_FN multiplied by STRIDE to the array STRIDE | |
| 1491 at the position corresponding to the loop of the step. N is the depth | |
| 1492 of the considered loop nest, and, LOOP is its innermost loop. */ | |
| 1493 | |
| 1494 static void | |
| 1495 add_subscript_strides (tree access_fn, unsigned stride, | |
| 1496 HOST_WIDE_INT *strides, unsigned n, struct loop *loop) | |
| 1497 { | |
| 1498 struct loop *aloop; | |
| 1499 tree step; | |
| 1500 HOST_WIDE_INT astep; | |
| 1501 unsigned min_depth = loop_depth (loop) - n; | |
| 1502 | |
| 1503 while (TREE_CODE (access_fn) == POLYNOMIAL_CHREC) | |
| 1504 { | |
| 1505 aloop = get_chrec_loop (access_fn); | |
| 1506 step = CHREC_RIGHT (access_fn); | |
| 1507 access_fn = CHREC_LEFT (access_fn); | |
| 1508 | |
| 1509 if ((unsigned) loop_depth (aloop) <= min_depth) | |
| 1510 continue; | |
| 1511 | |
| 111 | 1512 if (tree_fits_shwi_p (step)) |
| 1513 astep = tree_to_shwi (step); | |
| 0 | 1514 else |
| 1515 astep = L1_CACHE_LINE_SIZE; | |
| 1516 | |
| 1517 strides[n - 1 - loop_depth (loop) + loop_depth (aloop)] += astep * stride; | |
| 1518 | |
| 1519 } | |
| 1520 } | |
| 1521 | |
| 1522 /* Returns the volume of memory references accessed between two consecutive | |
| 1523 self-reuses of the reference DR. We consider the subscripts of DR in N | |
| 1524 loops, and LOOP_SIZES contains the volumes of accesses in each of the | |
| 1525 loops. LOOP is the innermost loop of the current loop nest. */ | |
| 1526 | |
| 1527 static unsigned | |
| 1528 self_reuse_distance (data_reference_p dr, unsigned *loop_sizes, unsigned n, | |
| 1529 struct loop *loop) | |
| 1530 { | |
| 1531 tree stride, access_fn; | |
| 1532 HOST_WIDE_INT *strides, astride; | |
| 111 | 1533 vec<tree> access_fns; |
| 0 | 1534 tree ref = DR_REF (dr); |
| 1535 unsigned i, ret = ~0u; | |
| 1536 | |
| 1537 /* In the following example: | |
| 1538 | |
| 1539 for (i = 0; i < N; i++) | |
| 1540 for (j = 0; j < N; j++) | |
| 1541 use (a[j][i]); | |
| 1542 the same cache line is accessed each N steps (except if the change from | |
| 1543 i to i + 1 crosses the boundary of the cache line). Thus, for self-reuse, | |
| 1544 we cannot rely purely on the results of the data dependence analysis. | |
| 1545 | |
| 1546 Instead, we compute the stride of the reference in each loop, and consider | |
| 1547 the innermost loop in that the stride is less than cache size. */ | |
| 1548 | |
| 1549 strides = XCNEWVEC (HOST_WIDE_INT, n); | |
| 1550 access_fns = DR_ACCESS_FNS (dr); | |
| 1551 | |
| 111 | 1552 FOR_EACH_VEC_ELT (access_fns, i, access_fn) |
| 0 | 1553 { |
| 1554 /* Keep track of the reference corresponding to the subscript, so that we | |
| 1555 know its stride. */ | |
| 1556 while (handled_component_p (ref) && TREE_CODE (ref) != ARRAY_REF) | |
| 1557 ref = TREE_OPERAND (ref, 0); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1558 |
| 0 | 1559 if (TREE_CODE (ref) == ARRAY_REF) |
| 1560 { | |
| 1561 stride = TYPE_SIZE_UNIT (TREE_TYPE (ref)); | |
| 111 | 1562 if (tree_fits_uhwi_p (stride)) |
| 1563 astride = tree_to_uhwi (stride); | |
| 0 | 1564 else |
| 1565 astride = L1_CACHE_LINE_SIZE; | |
| 1566 | |
| 1567 ref = TREE_OPERAND (ref, 0); | |
| 1568 } | |
| 1569 else | |
| 1570 astride = 1; | |
| 1571 | |
| 1572 add_subscript_strides (access_fn, astride, strides, n, loop); | |
| 1573 } | |
| 1574 | |
| 1575 for (i = n; i-- > 0; ) | |
| 1576 { | |
| 1577 unsigned HOST_WIDE_INT s; | |
| 1578 | |
| 1579 s = strides[i] < 0 ? -strides[i] : strides[i]; | |
| 1580 | |
| 1581 if (s < (unsigned) L1_CACHE_LINE_SIZE | |
| 1582 && (loop_sizes[i] | |
| 1583 > (unsigned) (L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION))) | |
| 1584 { | |
| 1585 ret = loop_sizes[i]; | |
| 1586 break; | |
| 1587 } | |
| 1588 } | |
| 1589 | |
| 1590 free (strides); | |
| 1591 return ret; | |
| 1592 } | |
| 1593 | |
| 1594 /* Determines the distance till the first reuse of each reference in REFS | |
| 1595 in the loop nest of LOOP. NO_OTHER_REFS is true if there are no other | |
| 111 | 1596 memory references in the loop. Return false if the analysis fails. */ |
| 0 | 1597 |
| 111 | 1598 static bool |
| 0 | 1599 determine_loop_nest_reuse (struct loop *loop, struct mem_ref_group *refs, |
| 1600 bool no_other_refs) | |
| 1601 { | |
| 1602 struct loop *nest, *aloop; | |
| 111 | 1603 vec<data_reference_p> datarefs = vNULL; |
| 1604 vec<ddr_p> dependences = vNULL; | |
| 0 | 1605 struct mem_ref_group *gr; |
| 1606 struct mem_ref *ref, *refb; | |
| 111 | 1607 auto_vec<loop_p> vloops; |
| 0 | 1608 unsigned *loop_data_size; |
| 1609 unsigned i, j, n; | |
| 1610 unsigned volume, dist, adist; | |
| 1611 HOST_WIDE_INT vol; | |
| 1612 data_reference_p dr; | |
| 1613 ddr_p dep; | |
| 1614 | |
| 1615 if (loop->inner) | |
| 111 | 1616 return true; |
| 0 | 1617 |
| 1618 /* Find the outermost loop of the loop nest of loop (we require that | |
| 1619 there are no sibling loops inside the nest). */ | |
| 1620 nest = loop; | |
| 1621 while (1) | |
| 1622 { | |
| 1623 aloop = loop_outer (nest); | |
| 1624 | |
| 1625 if (aloop == current_loops->tree_root | |
| 1626 || aloop->inner->next) | |
| 1627 break; | |
| 1628 | |
| 1629 nest = aloop; | |
| 1630 } | |
| 1631 | |
| 1632 /* For each loop, determine the amount of data accessed in each iteration. | |
| 1633 We use this to estimate whether the reference is evicted from the | |
| 1634 cache before its reuse. */ | |
| 1635 find_loop_nest (nest, &vloops); | |
| 111 | 1636 n = vloops.length (); |
| 0 | 1637 loop_data_size = XNEWVEC (unsigned, n); |
| 1638 volume = volume_of_references (refs); | |
| 1639 i = n; | |
| 1640 while (i-- != 0) | |
| 1641 { | |
| 1642 loop_data_size[i] = volume; | |
| 1643 /* Bound the volume by the L2 cache size, since above this bound, | |
| 1644 all dependence distances are equivalent. */ | |
| 1645 if (volume > L2_CACHE_SIZE_BYTES) | |
| 1646 continue; | |
| 1647 | |
| 111 | 1648 aloop = vloops[i]; |
| 1649 vol = estimated_stmt_executions_int (aloop); | |
| 1650 if (vol == -1) | |
| 0 | 1651 vol = expected_loop_iterations (aloop); |
| 1652 volume *= vol; | |
| 1653 } | |
| 1654 | |
| 1655 /* Prepare the references in the form suitable for data dependence | |
| 1656 analysis. We ignore unanalyzable data references (the results | |
| 1657 are used just as a heuristics to estimate temporality of the | |
| 1658 references, hence we do not need to worry about correctness). */ | |
| 1659 for (gr = refs; gr; gr = gr->next) | |
| 1660 for (ref = gr->refs; ref; ref = ref->next) | |
| 1661 { | |
| 111 | 1662 dr = create_data_ref (loop_preheader_edge (nest), |
| 1663 loop_containing_stmt (ref->stmt), | |
| 1664 ref->mem, ref->stmt, !ref->write_p, false); | |
| 0 | 1665 |
| 1666 if (dr) | |
| 1667 { | |
| 1668 ref->reuse_distance = volume; | |
| 1669 dr->aux = ref; | |
| 111 | 1670 datarefs.safe_push (dr); |
| 0 | 1671 } |
| 1672 else | |
| 1673 no_other_refs = false; | |
| 1674 } | |
| 1675 | |
| 111 | 1676 FOR_EACH_VEC_ELT (datarefs, i, dr) |
| 0 | 1677 { |
| 1678 dist = self_reuse_distance (dr, loop_data_size, n, loop); | |
| 1679 ref = (struct mem_ref *) dr->aux; | |
| 1680 if (ref->reuse_distance > dist) | |
| 1681 ref->reuse_distance = dist; | |
| 1682 | |
| 1683 if (no_other_refs) | |
| 1684 ref->independent_p = true; | |
| 1685 } | |
| 1686 | |
| 111 | 1687 if (!compute_all_dependences (datarefs, &dependences, vloops, true)) |
| 1688 return false; | |
| 0 | 1689 |
| 111 | 1690 FOR_EACH_VEC_ELT (dependences, i, dep) |
| 0 | 1691 { |
| 1692 if (DDR_ARE_DEPENDENT (dep) == chrec_known) | |
| 1693 continue; | |
| 1694 | |
| 1695 ref = (struct mem_ref *) DDR_A (dep)->aux; | |
| 1696 refb = (struct mem_ref *) DDR_B (dep)->aux; | |
| 1697 | |
| 1698 if (DDR_ARE_DEPENDENT (dep) == chrec_dont_know | |
| 111 | 1699 || DDR_COULD_BE_INDEPENDENT_P (dep) |
| 0 | 1700 || DDR_NUM_DIST_VECTS (dep) == 0) |
| 1701 { | |
| 1702 /* If the dependence cannot be analyzed, assume that there might be | |
| 1703 a reuse. */ | |
| 1704 dist = 0; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1705 |
| 0 | 1706 ref->independent_p = false; |
| 1707 refb->independent_p = false; | |
| 1708 } | |
| 1709 else | |
| 1710 { | |
| 1711 /* The distance vectors are normalized to be always lexicographically | |
| 1712 positive, hence we cannot tell just from them whether DDR_A comes | |
| 1713 before DDR_B or vice versa. However, it is not important, | |
| 1714 anyway -- if DDR_A is close to DDR_B, then it is either reused in | |
| 1715 DDR_B (and it is not nontemporal), or it reuses the value of DDR_B | |
| 1716 in cache (and marking it as nontemporal would not affect | |
| 1717 anything). */ | |
| 1718 | |
| 1719 dist = volume; | |
| 1720 for (j = 0; j < DDR_NUM_DIST_VECTS (dep); j++) | |
| 1721 { | |
| 1722 adist = volume_of_dist_vector (DDR_DIST_VECT (dep, j), | |
| 1723 loop_data_size, n); | |
| 1724 | |
| 1725 /* If this is a dependence in the innermost loop (i.e., the | |
| 1726 distances in all superloops are zero) and it is not | |
| 1727 the trivial self-dependence with distance zero, record that | |
| 1728 the references are not completely independent. */ | |
| 1729 if (lambda_vector_zerop (DDR_DIST_VECT (dep, j), n - 1) | |
| 1730 && (ref != refb | |
| 1731 || DDR_DIST_VECT (dep, j)[n-1] != 0)) | |
| 1732 { | |
| 1733 ref->independent_p = false; | |
| 1734 refb->independent_p = false; | |
| 1735 } | |
| 1736 | |
| 1737 /* Ignore accesses closer than | |
| 1738 L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION, | |
| 1739 so that we use nontemporal prefetches e.g. if single memory | |
| 1740 location is accessed several times in a single iteration of | |
| 1741 the loop. */ | |
| 1742 if (adist < L1_CACHE_SIZE_BYTES / NONTEMPORAL_FRACTION) | |
| 1743 continue; | |
| 1744 | |
| 1745 if (adist < dist) | |
| 1746 dist = adist; | |
| 1747 } | |
| 1748 } | |
| 1749 | |
| 1750 if (ref->reuse_distance > dist) | |
| 1751 ref->reuse_distance = dist; | |
| 1752 if (refb->reuse_distance > dist) | |
| 1753 refb->reuse_distance = dist; | |
| 1754 } | |
| 1755 | |
| 1756 free_dependence_relations (dependences); | |
| 1757 free_data_refs (datarefs); | |
| 1758 free (loop_data_size); | |
| 1759 | |
| 1760 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1761 { | |
| 1762 fprintf (dump_file, "Reuse distances:\n"); | |
| 1763 for (gr = refs; gr; gr = gr->next) | |
| 1764 for (ref = gr->refs; ref; ref = ref->next) | |
| 111 | 1765 fprintf (dump_file, " reference %u:%u distance %u\n", |
| 1766 ref->group->uid, ref->uid, ref->reuse_distance); | |
| 0 | 1767 } |
| 111 | 1768 |
| 1769 return true; | |
| 0 | 1770 } |
| 1771 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1772 /* Determine whether or not the trip count to ahead ratio is too small based |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1773 on prefitablility consideration. |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1774 AHEAD: the iteration ahead distance, |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1775 EST_NITER: the estimated trip count. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1776 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1777 static bool |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1778 trip_count_to_ahead_ratio_too_small_p (unsigned ahead, HOST_WIDE_INT est_niter) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1779 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1780 /* Assume trip count to ahead ratio is big enough if the trip count could not |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1781 be estimated at compile time. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1782 if (est_niter < 0) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1783 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1784 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1785 if (est_niter < (HOST_WIDE_INT) (TRIP_COUNT_TO_AHEAD_RATIO * ahead)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1786 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1787 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1788 fprintf (dump_file, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1789 "Not prefetching -- loop estimated to roll only %d times\n", |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1790 (int) est_niter); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1791 return true; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1792 } |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1793 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1794 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1795 } |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1796 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1797 /* Determine whether or not the number of memory references in the loop is |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1798 reasonable based on the profitablity and compilation time considerations. |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1799 NINSNS: estimated number of instructions in the loop, |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1800 MEM_REF_COUNT: total number of memory references in the loop. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1801 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1802 static bool |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1803 mem_ref_count_reasonable_p (unsigned ninsns, unsigned mem_ref_count) |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1804 { |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1805 int insn_to_mem_ratio; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1806 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1807 if (mem_ref_count == 0) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1808 return false; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1809 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1810 /* Miss rate computation (is_miss_rate_acceptable) and dependence analysis |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1811 (compute_all_dependences) have high costs based on quadratic complexity. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1812 To avoid huge compilation time, we give up prefetching if mem_ref_count |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1813 is too large. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1814 if (mem_ref_count > PREFETCH_MAX_MEM_REFS_PER_LOOP) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1815 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1816 |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1817 /* Prefetching improves performance by overlapping cache missing |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1818 memory accesses with CPU operations. If the loop does not have |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1819 enough CPU operations to overlap with memory operations, prefetching |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1820 won't give a significant benefit. One approximate way of checking |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1821 this is to require the ratio of instructions to memory references to |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1822 be above a certain limit. This approximation works well in practice. |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1823 TODO: Implement a more precise computation by estimating the time |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1824 for each CPU or memory op in the loop. Time estimates for memory ops |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1825 should account for cache misses. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1826 insn_to_mem_ratio = ninsns / mem_ref_count; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1827 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1828 if (insn_to_mem_ratio < PREFETCH_MIN_INSN_TO_MEM_RATIO) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1829 { |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1830 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1831 fprintf (dump_file, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1832 "Not prefetching -- instruction to memory reference ratio (%d) too small\n", |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1833 insn_to_mem_ratio); |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1834 return false; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1835 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1836 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1837 return true; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1838 } |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1839 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1840 /* Determine whether or not the instruction to prefetch ratio in the loop is |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1841 too small based on the profitablity consideration. |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1842 NINSNS: estimated number of instructions in the loop, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1843 PREFETCH_COUNT: an estimate of the number of prefetches, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1844 UNROLL_FACTOR: the factor to unroll the loop if prefetching. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1845 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1846 static bool |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1847 insn_to_prefetch_ratio_too_small_p (unsigned ninsns, unsigned prefetch_count, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1848 unsigned unroll_factor) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1849 { |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1850 int insn_to_prefetch_ratio; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1851 |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1852 /* Prefetching most likely causes performance degradation when the instruction |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1853 to prefetch ratio is too small. Too many prefetch instructions in a loop |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1854 may reduce the I-cache performance. |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1855 (unroll_factor * ninsns) is used to estimate the number of instructions in |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1856 the unrolled loop. This implementation is a bit simplistic -- the number |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1857 of issued prefetch instructions is also affected by unrolling. So, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1858 prefetch_mod and the unroll factor should be taken into account when |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1859 determining prefetch_count. Also, the number of insns of the unrolled |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1860 loop will usually be significantly smaller than the number of insns of the |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1861 original loop * unroll_factor (at least the induction variable increases |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1862 and the exit branches will get eliminated), so it might be better to use |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1863 tree_estimate_loop_size + estimated_unrolled_size. */ |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1864 insn_to_prefetch_ratio = (unroll_factor * ninsns) / prefetch_count; |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1865 if (insn_to_prefetch_ratio < MIN_INSN_TO_PREFETCH_RATIO) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1866 { |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1867 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1868 fprintf (dump_file, |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1869 "Not prefetching -- instruction to prefetch ratio (%d) too small\n", |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1870 insn_to_prefetch_ratio); |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1871 return true; |
|
63
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1872 } |
|
b7f97abdc517
update gcc from gcc-4.5.0 to gcc-4.6
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
55
diff
changeset
|
1873 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1874 return false; |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1875 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1876 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1877 |
| 0 | 1878 /* Issue prefetch instructions for array references in LOOP. Returns |
| 1879 true if the LOOP was unrolled. */ | |
| 1880 | |
| 1881 static bool | |
| 1882 loop_prefetch_arrays (struct loop *loop) | |
| 1883 { | |
| 1884 struct mem_ref_group *refs; | |
| 1885 unsigned ahead, ninsns, time, unroll_factor; | |
| 1886 HOST_WIDE_INT est_niter; | |
| 1887 struct tree_niter_desc desc; | |
| 1888 bool unrolled = false, no_other_refs; | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1889 unsigned prefetch_count; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1890 unsigned mem_ref_count; |
| 0 | 1891 |
| 1892 if (optimize_loop_nest_for_size_p (loop)) | |
| 1893 { | |
| 1894 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1895 fprintf (dump_file, " ignored (cold area)\n"); | |
| 1896 return false; | |
| 1897 } | |
| 1898 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1899 /* FIXME: the time should be weighted by the probabilities of the blocks in |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1900 the loop body. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1901 time = tree_num_loop_insns (loop, &eni_time_weights); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1902 if (time == 0) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1903 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1904 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1905 ahead = (PREFETCH_LATENCY + time - 1) / time; |
| 111 | 1906 est_niter = estimated_stmt_executions_int (loop); |
| 1907 if (est_niter == -1) | |
| 1908 est_niter = likely_max_stmt_executions_int (loop); | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1909 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1910 /* Prefetching is not likely to be profitable if the trip count to ahead |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1911 ratio is too small. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1912 if (trip_count_to_ahead_ratio_too_small_p (ahead, est_niter)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1913 return false; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1914 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1915 ninsns = tree_num_loop_insns (loop, &eni_size_weights); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1916 |
| 0 | 1917 /* Step 1: gather the memory references. */ |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1918 refs = gather_memory_references (loop, &no_other_refs, &mem_ref_count); |
| 0 | 1919 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1920 /* Give up prefetching if the number of memory references in the |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1921 loop is not reasonable based on profitablity and compilation time |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1922 considerations. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1923 if (!mem_ref_count_reasonable_p (ninsns, mem_ref_count)) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1924 goto fail; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1925 |
| 0 | 1926 /* Step 2: estimate the reuse effects. */ |
| 1927 prune_by_reuse (refs); | |
| 1928 | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1929 if (nothing_to_prefetch_p (refs)) |
| 0 | 1930 goto fail; |
| 1931 | |
| 111 | 1932 if (!determine_loop_nest_reuse (loop, refs, no_other_refs)) |
| 1933 goto fail; | |
| 0 | 1934 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1935 /* Step 3: determine unroll factor. */ |
| 0 | 1936 unroll_factor = determine_unroll_factor (loop, refs, ninsns, &desc, |
| 1937 est_niter); | |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1938 |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1939 /* Estimate prefetch count for the unrolled loop. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1940 prefetch_count = estimate_prefetch_count (refs, unroll_factor); |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1941 if (prefetch_count == 0) |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1942 goto fail; |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1943 |
| 0 | 1944 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1945 fprintf (dump_file, "Ahead %d, unroll factor %d, trip count " |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1946 HOST_WIDE_INT_PRINT_DEC "\n" |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1947 "insn count %d, mem ref count %d, prefetch count %d\n", |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1948 ahead, unroll_factor, est_niter, |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1949 ninsns, mem_ref_count, prefetch_count); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1950 |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1951 /* Prefetching is not likely to be profitable if the instruction to prefetch |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1952 ratio is too small. */ |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1953 if (insn_to_prefetch_ratio_too_small_p (ninsns, prefetch_count, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
1954 unroll_factor)) |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1955 goto fail; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1956 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1957 mark_nontemporal_stores (loop, refs); |
| 0 | 1958 |
| 1959 /* Step 4: what to prefetch? */ | |
| 1960 if (!schedule_prefetches (refs, unroll_factor, ahead)) | |
| 1961 goto fail; | |
| 1962 | |
| 1963 /* Step 5: unroll the loop. TODO -- peeling of first and last few | |
| 1964 iterations so that we do not issue superfluous prefetches. */ | |
| 1965 if (unroll_factor != 1) | |
| 1966 { | |
| 1967 tree_unroll_loop (loop, unroll_factor, | |
| 1968 single_dom_exit (loop), &desc); | |
| 1969 unrolled = true; | |
| 1970 } | |
| 1971 | |
| 1972 /* Step 6: issue the prefetches. */ | |
| 1973 issue_prefetches (refs, unroll_factor, ahead); | |
| 1974 | |
| 1975 fail: | |
| 1976 release_mem_refs (refs); | |
| 1977 return unrolled; | |
| 1978 } | |
| 1979 | |
| 1980 /* Issue prefetch instructions for array references in loops. */ | |
| 1981 | |
| 1982 unsigned int | |
| 1983 tree_ssa_prefetch_arrays (void) | |
| 1984 { | |
| 1985 struct loop *loop; | |
| 1986 bool unrolled = false; | |
| 1987 int todo_flags = 0; | |
| 1988 | |
| 111 | 1989 if (!targetm.have_prefetch () |
| 0 | 1990 /* It is possible to ask compiler for say -mtune=i486 -march=pentium4. |
| 1991 -mtune=i486 causes us having PREFETCH_BLOCK 0, since this is part | |
| 1992 of processor costs and i486 does not have prefetch, but | |
| 111 | 1993 -march=pentium4 causes targetm.have_prefetch to be true. Ugh. */ |
| 0 | 1994 || PREFETCH_BLOCK == 0) |
| 1995 return 0; | |
| 1996 | |
| 1997 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1998 { | |
| 1999 fprintf (dump_file, "Prefetching parameters:\n"); | |
| 2000 fprintf (dump_file, " simultaneous prefetches: %d\n", | |
| 2001 SIMULTANEOUS_PREFETCHES); | |
| 2002 fprintf (dump_file, " prefetch latency: %d\n", PREFETCH_LATENCY); | |
| 2003 fprintf (dump_file, " prefetch block size: %d\n", PREFETCH_BLOCK); | |
| 2004 fprintf (dump_file, " L1 cache size: %d lines, %d kB\n", | |
| 2005 L1_CACHE_SIZE_BYTES / L1_CACHE_LINE_SIZE, L1_CACHE_SIZE); | |
| 2006 fprintf (dump_file, " L1 cache line size: %d\n", L1_CACHE_LINE_SIZE); | |
| 2007 fprintf (dump_file, " L2 cache size: %d kB\n", L2_CACHE_SIZE); | |
|
55
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
2008 fprintf (dump_file, " min insn-to-prefetch ratio: %d \n", |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
2009 MIN_INSN_TO_PREFETCH_RATIO); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
2010 fprintf (dump_file, " min insn-to-mem ratio: %d \n", |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
2011 PREFETCH_MIN_INSN_TO_MEM_RATIO); |
| 0 | 2012 fprintf (dump_file, "\n"); |
| 2013 } | |
| 2014 | |
| 2015 initialize_original_copy_tables (); | |
| 2016 | |
| 111 | 2017 if (!builtin_decl_explicit_p (BUILT_IN_PREFETCH)) |
| 0 | 2018 { |
|
67
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
2019 tree type = build_function_type_list (void_type_node, |
|
f6334be47118
update gcc from gcc-4.6-20100522 to gcc-4.6-20110318
nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
parents:
63
diff
changeset
|
2020 const_ptr_type_node, NULL_TREE); |
| 0 | 2021 tree decl = add_builtin_function ("__builtin_prefetch", type, |
| 2022 BUILT_IN_PREFETCH, BUILT_IN_NORMAL, | |
| 2023 NULL, NULL_TREE); | |
| 2024 DECL_IS_NOVOPS (decl) = true; | |
| 111 | 2025 set_builtin_decl (BUILT_IN_PREFETCH, decl, false); |
| 0 | 2026 } |
| 2027 | |
| 111 | 2028 FOR_EACH_LOOP (loop, LI_FROM_INNERMOST) |
| 0 | 2029 { |
| 2030 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 2031 fprintf (dump_file, "Processing loop %d:\n", loop->num); | |
| 2032 | |
| 2033 unrolled |= loop_prefetch_arrays (loop); | |
| 2034 | |
| 2035 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 2036 fprintf (dump_file, "\n\n"); | |
| 2037 } | |
| 2038 | |
| 2039 if (unrolled) | |
| 2040 { | |
| 2041 scev_reset (); | |
| 2042 todo_flags |= TODO_cleanup_cfg; | |
| 2043 } | |
| 2044 | |
| 2045 free_original_copy_tables (); | |
| 2046 return todo_flags; | |
| 2047 } | |
| 111 | 2048 |
| 2049 /* Prefetching. */ | |
| 2050 | |
| 2051 namespace { | |
| 2052 | |
| 2053 const pass_data pass_data_loop_prefetch = | |
| 2054 { | |
| 2055 GIMPLE_PASS, /* type */ | |
| 2056 "aprefetch", /* name */ | |
| 2057 OPTGROUP_LOOP, /* optinfo_flags */ | |
| 2058 TV_TREE_PREFETCH, /* tv_id */ | |
| 2059 ( PROP_cfg | PROP_ssa ), /* properties_required */ | |
| 2060 0, /* properties_provided */ | |
| 2061 0, /* properties_destroyed */ | |
| 2062 0, /* todo_flags_start */ | |
| 2063 0, /* todo_flags_finish */ | |
| 2064 }; | |
| 2065 | |
| 2066 class pass_loop_prefetch : public gimple_opt_pass | |
| 2067 { | |
| 2068 public: | |
| 2069 pass_loop_prefetch (gcc::context *ctxt) | |
| 2070 : gimple_opt_pass (pass_data_loop_prefetch, ctxt) | |
| 2071 {} | |
| 2072 | |
| 2073 /* opt_pass methods: */ | |
| 2074 virtual bool gate (function *) { return flag_prefetch_loop_arrays > 0; } | |
| 2075 virtual unsigned int execute (function *); | |
| 2076 | |
| 2077 }; // class pass_loop_prefetch | |
| 2078 | |
| 2079 unsigned int | |
| 2080 pass_loop_prefetch::execute (function *fun) | |
| 2081 { | |
| 2082 if (number_of_loops (fun) <= 1) | |
| 2083 return 0; | |
| 2084 | |
| 2085 if ((PREFETCH_BLOCK & (PREFETCH_BLOCK - 1)) != 0) | |
| 2086 { | |
| 2087 static bool warned = false; | |
| 2088 | |
| 2089 if (!warned) | |
| 2090 { | |
| 2091 warning (OPT_Wdisabled_optimization, | |
| 2092 "%<l1-cache-size%> parameter is not a power of two %d", | |
| 2093 PREFETCH_BLOCK); | |
| 2094 warned = true; | |
| 2095 } | |
| 2096 return 0; | |
| 2097 } | |
| 2098 | |
| 2099 return tree_ssa_prefetch_arrays (); | |
| 2100 } | |
| 2101 | |
| 2102 } // anon namespace | |
| 2103 | |
| 2104 gimple_opt_pass * | |
| 2105 make_pass_loop_prefetch (gcc::context *ctxt) | |
| 2106 { | |
| 2107 return new pass_loop_prefetch (ctxt); | |
| 2108 } | |
| 2109 | |
| 2110 |