[Bug tree-optimization/49849] loop optimization prevents vectorization

[vincenzo.innocente at cern dot ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49849

--- Comment #1 from vincenzo Innocente <vincenzo.innocente at cern dot ch> 
2011-07-26 08:30:45 UTC ---
it may be a duplicate of my own PR49730
as

void bar2(int jj) {
  const int S=8;
  float x[S];
  float y[S];
  int j = jj*S;
  for (int i=0; i!=S; ++i)
    x[i] = co[k[j+i]];
  for (int i=0; i!=S; ++i) // this should vectorize
    y[i] = a[j+i]/std::sqrt(x[i]*b[j+i]);
  for (int i=0; i!=S; ++i)
    ++hist[int(y[i])];
} 

vectorize at 03

(of course in the example I submitted previously the external loop should read

  for (int jj=0; jj!=loops; ++jj) {
    int j = jj*S;

)