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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [testsuite/] [gcc.dg/] [tree-ssa/] [pr19210-1.c] - Rev 298
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/* { dg-do compile } */ /* { dg-options "-O2 -Wunsafe-loop-optimizations" } */ extern void g(void); void f (unsigned n) { unsigned k; for(k = 0;k <= n;k++) /* { dg-warning "cannot optimize.*infinite loops" } */ g(); for(k = 0;k <= n;k += 4) /* { dg-warning "cannot optimize.*overflow" } */ g(); /* We used to get warning for this loop. However, since then # of iterations analysis improved, and we can now prove that this loop does not verflow. This is because the only case when it would overflow is if n = ~0 (since ~0 is divisible by 5), and this cannot be the case, since when we got here, the previous loop exited, thus there exists k > n. */ for(k = 5;k <= n;k += 5) g(); /* So we need the following loop, instead. */ for(k = 4;k <= n;k += 5) /* { dg-warning "cannot optimize.*overflow" } */ g(); for(k = 15;k >= n;k--) /* { dg-warning "cannot optimize.*infinite" } */ g(); }