1 /* { dg-do compile { target { i?86-*-* x86_64-*-* } } } */
2 /* { dg-options "-O2 -fprefetch-loop-arrays -march=amdfam10 --param min-insn-to-prefetch-ratio=5 -fdump-tree-aprefetch-details" } */
3
4 /* These are common idioms for writing variable-length arrays at the end
5 of structures. We should not deduce anything about the number of iterations
6 of the loops from them. */
7
8 struct tail0
9 {
10 int xxx;
11 int yyy[0];
12 };
13
loop0(int n,struct tail0 * x)14 int loop0 (int n, struct tail0 *x)
15 {
16 int i, s = 0;
17
18 for (i = 0; i < n; i++)
19 s += x->yyy[i];
20
21 return s;
22 }
23
24 struct tail1
25 {
26 int xxx;
27 int yyy[1];
28 };
loop1(int n,struct tail1 * x)29 int loop1 (int n, struct tail1 *x)
30 {
31 int i, s = 0;
32
33 for (i = 0; i < n; i++)
34 s += x->yyy[i];
35
36 return s;
37 }
38
39 /* It is unlikely that this should be a tail array. We may deduce that most
40 likely, the loop iterates about 5 times, and the array is not worth prefetching. */
41
42 struct tail5
43 {
44 int xxx;
45 int yyy[5];
46 };
loop5(int n,struct tail5 * x)47 int loop5 (int n, struct tail5 *x)
48 {
49 int i, s = 0;
50
51 for (i = 0; i < n; i++)
52 s += x->yyy[i];
53
54 return s;
55 }
56
57 /* Until we are able to track likely upper bounds, we can't really work out that
58 small trailing arrays should not be prefetched. */
59 /* { dg-final { scan-tree-dump-times "Issued prefetch" 2 "aprefetch" } } */
60 /* { dg-final { scan-tree-dump-times "Not prefetching" 1 "aprefetch" } } */
61