Merge from mainline
[official-gcc.git] / gcc / testsuite / gcc.dg / tree-ssa / pr19210-1.c
blob906132c6916c0fde5d936b0c8b2c9524c3870de5
1 /* { dg-do compile } */
2 /* { dg-options "-O2 -Wunsafe-loop-optimizations" } */
3 extern void g(void);
5 void
6 f (unsigned n)
8 unsigned k;
9 for(k = 0;k <= n;k++) /* { dg-warning "cannot optimize.*infinite loops" } */
10 g();
12 for(k = 0;k <= n;k += 4) /* { dg-warning "cannot optimize.*overflow" } */
13 g();
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();
23 /* So we need the following loop, instead. */
24 for(k = 4;k <= n;k += 5) /* { dg-warning "cannot optimize.*overflow" } */
25 g();
27 for(k = 15;k >= n;k--) /* { dg-warning "cannot optimize.*infinite" } */
28 g();