message: Use poplibs cosine operator
diff: @@ -44,6 +44,7 @@ LookupUnaryFn(HloOpcode opcode) {
  switch (opcode) {
  case HloOpcode::kAbs: return popstd::abs;
  case HloOpcode::kCeil: return popstd::ceil;
  + case HloOpcode::kCos: return popstd::cos;
  case HloOpcode::kExp: return popstd::exp;
  case HloOpcode::kFloor: return popstd::floor;
  case HloOpcode::kLog: return popstd::log;
  @@ -52,7 +53,6 @@ LookupUnaryFn(HloOpcode opcode) {
  case HloOpcode::kSign: return popstd::signum;
  case HloOpcode::kTanh: return popstd::tanh;
  - case HloOpcode::kCos:
  case HloOpcode::kIsFinite:
  default:
  break;
  