Invariant is not moved out of loop

[Astor Piaz <appiazzolla at gmail dot com>]

Hello All,

I have two nested loops and I cannot get the loop invariants to move
using gcc 7.1.0 as shown in the assembly.
I attach a simple example to the end of this e-mail. I am using -Ofast
-fmove-loop-invariants -fassociative-math.
Would you be so kind as to help me figuring out what I am doing wrong?

Thanks,
--
Astor

Original loop:

int main()
{
const unsigned int k=10;
const double u[k*k*k] = {3.14} ;
const double phi[k] = {3.14} ;
double f = 0.;
for (unsigned int i3 = 0;i3<k;++i3)
for (unsigned int i2 = 0;i2<k;++i2)
for (unsigned int i1 = 0;i1<k;++i1)
  f += u[i1+k*(i2+k*i3)] * phi[i1] * phi[i2] * phi[i3];
return static_cast<unsigned int>(f);
}

Loop with the invariants moved:

int main()
{
const unsigned int k=10;
const double u[k*k*k] = {3.14} ;
const double phi[k] = {3.14} ;
double f3 = 0.;
for (unsigned int i3 = 0;i3<k;++i3)
{
  const unsigned int k3 = k*i3;
  double f2 = 0.;
  for (unsigned int i2 = 0;i2<k;++i2)
  {
    const unsigned int k2 = k*(i2+k3);
    double f1 = 0.;
      for (unsigned int i1 = 0;i1<k;++i1)
      {
        f1 += u[i1+k2] * phi[i1];
      }
    f2 += f1 * phi[i2];
  }
f3 += f2 * phi[i3];
}
return static_cast<unsigned int>(f3);
}