[Bug tree-optimization/69873] New: Vectorizer fails to emit runtime profitability check if no peeling/versioning is done

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69873

            Bug ID: 69873
           Summary: Vectorizer fails to emit runtime profitability check
                    if no peeling/versioning is done
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

double a[1024];
void foo (unsigned n)
{
  for (unsigned i = 0; i < n * 2; ++i)
    a[i] = 1.;
}

currently says the threshold is > 3 iterations but no such guard is added
(whether that's a reasonable threshold is another question of course).