[Bug tree-optimization/108677] New: wrong vectorization (when copy constructor is present?)

[vincenzo.innocente at cern dot ch via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108677

            Bug ID: 108677
           Summary: wrong vectorization (when copy constructor is
                    present?)
           Product: gcc
           Version: 12.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vincenzo.innocente at cern dot ch
  Target Milestone: ---

in this real life code

#include<cmath>

struct trig_pair {
   double CosPhi;
   double SinPhi;

   trig_pair() : CosPhi(1.), SinPhi(0.) {}
   trig_pair(const trig_pair &tp) : CosPhi(tp.CosPhi), SinPhi(tp.SinPhi) {}
   trig_pair(const double C, const double S) : CosPhi(C), SinPhi(S) {}
   trig_pair(const double phi) : CosPhi(cos(phi)), SinPhi(sin(phi)) {}

   //Return trig_pair fo angle increased by angle of tp.
   trig_pair Add(const trig_pair &tp) {
      return trig_pair(this->CosPhi*tp.CosPhi - this->SinPhi*tp.SinPhi,
                       this->SinPhi*tp.CosPhi + this->CosPhi*tp.SinPhi);
   }
};

trig_pair *TrigArr;

void FillTrigArr(trig_pair tp, unsigned MaxM)
{
//Fill TrigArr with trig_pair(jp*phi)
   if (!TrigArr) return;;
   TrigArr[1] = tp;
   for (unsigned jp = 2; jp <= MaxM; ++jp) TrigArr[jp] = TrigArr[jp-1].Add(tp);
}


gcc vectorize the loop even if a dependency is present...[1]
It will not if I comment out the copy contructor...[2]


[1]
https://godbolt.org/z/vhPeh35n5

[2]
https://godbolt.org/z/YPjdYdqG8