[Bug tree-optimization/47860] is vectorization of "condition in nested loop" supported

["vincenzo.innocente at cern dot ch" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47860

--- Comment #1 from vincenzo Innocente <vincenzo.innocente at cern dot ch> 2011-02-23 16:32:36 UTC ---
it seems that there is a problem in the use of  "unsigned int":
shall I open a different bug report?

even a simple comparison fails to vectorize

float amin(float * c, unsigned int N) {
  float min=c[0];
  for (unsigned int i=1; i!=N; ++i)
    min = min > c[i] ? c[i] : min;
  return min;
}


while it DOES vectorize when I change it in
float amin(float * c, int N) {
  float min=c[0];
  for (int i=1; i!=N; ++i)
    min = min > c[i] ? c[i] : min;
  return min;
}




still the nested loop does not vectorize yet

cat nestedCond.cc
void nestedCond( double * __restrict__ x_in,  double * __restrict__ x_out, 
double * __restrict__ a,  double * __restrict__ c, int M, int N) {   
for (int j = 0; j < M; j++)
    {
      double x = x_in[j];
      double curr_a = a[0];

      for (int i = 0; i < N; i++)
        {
          double next_a = a[i+1];
          curr_a = x > c[i] ? curr_a : next_a;
        }

      x_out[j] = curr_a;
    }
}
gcc -O3 -ffast-math -Wall -c nestedCond.cc -ftree-vectorizer-verbose=7

nestedCond.cc:2: note: not vectorized: control flow in loop.
nestedCond.cc:7: note: not vectorized: unsupported use in stmt.
nestedCond.cc:7: note: not vectorized: unsupported use in stmt.
nestedCond.cc:1: note: vectorized 0 loops in function.