1 /* { dg-do compile } */
2 /* { dg-options "-O2 -fopt-info-loop-missed -Wunsafe-loop-optimizations" } */
3 extern void g(void);
4
5 void
f(unsigned n)6 f (unsigned n)
7 {
8 unsigned k;
9 for(k = 0;k <= n;k++) /* { dg-message "note: missed loop optimization: niters analysis .*" } */
10 g();
11
12 for(k = 0;k <= n;k += 4) /* { dg-message "note: missed loop optimization: niters analysis .*" } */
13 g();
14
15 /* We used to get warning for this loop. However, since then # of iterations
16 analysis improved, and we can now prove that this loop does not verflow.
17 This is because the only case when it would overflow is if n = ~0 (since
18 ~0 is divisible by 5), and this cannot be the case, since when we got
19 here, the previous loop exited, thus there exists k > n. */
20 for(k = 5;k <= n;k += 5)
21 g();
22
23 /* So we need the following loop, instead. */
24 for(k = 4;k <= n;k += 5) /* { dg-message "note: missed loop optimization: niters analysis .*" } */
25 g();
26
27 for(k = 15;k >= n;k--) /* { dg-message "note: missed loop optimization: niters analysis .*" } */
28 g();
29 }
30