[Bug tree-optimization/105053] Wrong loop count for scalar code from vectorizer

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105053

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #2)
> (In reply to Richard Biener from comment #1)
> > It also reproduces with n == 16 for me - can you produce a testcase with a
> > static initializer that's known to fail please?
> 
> And n == 4, but std::cout << vec; doesn't like me :P

1597201307 1817606674
1380347796 1721941769
837975613 1032707773
1173654292 2020064272

Testcase:

#include <vector>
#include <tuple>
#include <algorithm>

int main()
{
  const int n = 4;
  std::vector<std::tuple<int,int,double>> vec
      = { { 1597201307, 1817606674, 0. },
            { 1380347796, 1721941769, 0.},
            {837975613, 1032707773, 0.},
            {1173654292, 2020064272, 0.} } ;
  int sup1 = 0;
  for(int i=0;i<n;++i)
    sup1=std::max(sup1,std::max(std::get<0>(vec[i]),std::get<1>(vec[i])));
  int sup2 = 0;
  for(int i=0;i<n;++i)
    sup2=std::max(std::max(sup2,std::get<0>(vec[i])),std::get<1>(vec[i]));
  if (sup1 != sup2)
    std::abort ();
  return 0;
}