view gcc/testsuite/gcc.dg/tree-ssa/pr19210-1.c @ 131:84e7813d76e9

gcc-8.2
author mir3636
date Thu, 25 Oct 2018 07:37:49 +0900
parents 04ced10e8804
children
line wrap: on
line source

/* { dg-do compile } */
/* { dg-options "-O2 -fopt-info-loop-missed" } */
extern void g(void);

void
f (unsigned n)
{
  unsigned k;
  for(k = 0;k <= n;k++) /* { dg-missed "missed loop optimization: niters analysis .*" } */
    g();

  for(k = 0;k <= n;k += 4) /* { dg-missed "missed loop optimization: niters analysis .*" } */
    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-missed "missed loop optimization: niters analysis .*" } */
    g();
  
  for(k = 15;k >= n;k--) /* { dg-missed "missed loop optimization: niters analysis .*" } */
    g();
}