message: Call expm1(x) instead of exp(x) - 1.
  It has higher precision and is potentially faster (depending on hardware).
diff: @@ -42,10 +42,10 @@ std::string GetOneInputCode(const OperationType& op_type,
  result = "\n";
  break;
  case OperationType::ELU:
  - result = "$0.x = $0.x < (FLT)(0.0f) ? exp($0.x) - (FLT)(1.0f) : $0.x;\n";
  - result += "$0.y = $0.y < (FLT)(0.0f) ? exp($0.y) - (FLT)(1.0f) : $0.y;\n";
  - result += "$0.z = $0.z < (FLT)(0.0f) ? exp($0.z) - (FLT)(1.0f) : $0.z;\n";
  - result += "$0.w = $0.w < (FLT)(0.0f) ? exp($0.w) - (FLT)(1.0f) : $0.w;\n";
  + result = "$0.x = $0.x < (FLT)(0.0f) ? expm1($0.x) : $0.x;\n";
  + result += "$0.y = $0.y < (FLT)(0.0f) ? expm1($0.y) : $0.y;\n";
  + result += "$0.z = $0.z < (FLT)(0.0f) ? expm1($0.z) : $0.z;\n";
  + result += "$0.w = $0.w < (FLT)(0.0f) ? expm1($0.w) : $0.w;\n";
  break;
  case OperationType::EXP:
  result = "$0 = exp($0);\n";
  