[cfe-dev] Restrict for values that are not parameters

[Mark Schimmel]

I cannot get Clang to add noalias via a cast operation. This code does not produce any warnings, and I believe it's legal, but the restrict qualifier is lost.  Am I incorrect about this code being legal?  Any idea why the qualifier is stripped?  (It is a contrived example. You could imagine address checking and two separate loops.)

#define NOALIAS __restrict
//#define NOALIAS __attribute__((noalias))

void move(
    int* velocity_x, int* velocity_y, int* velocity_z,
    int* position_x,int* position_y,int* position_z,
    int* acceleration_x, int* acceleration_y, int* acceleration_z,
    int             time_step,
    int            count,
    int            stride )
{
    {
        int* NOALIAS r_acceleration_x = (int* NOALIAS)acceleration_x;
        int* NOALIAS r_velocity_x     = (int* NOALIAS)velocity_x;
        int* NOALIAS r_position_x     = (int* NOALIAS)position_x;
        int* NOALIAS r_acceleration_y = (int* NOALIAS)acceleration_y;
        int* NOALIAS r_velocity_y     = (int* NOALIAS)velocity_y;
        int* NOALIAS r_position_y     = (int* NOALIAS)position_y;
        int* NOALIAS r_acceleration_z = (int* NOALIAS)acceleration_z;
        int* NOALIAS r_velocity_z     = (int* NOALIAS)velocity_z;
        int* NOALIAS r_position_z     = (int* NOALIAS)position_z;

        for (int i=0;i<count*stride;i+=stride)
        {
            r_velocity_x[i] += r_acceleration_x[i] * time_step;
            r_velocity_y[i] += r_acceleration_y[i] * time_step;
            r_velocity_z[i] += r_acceleration_z[i] * time_step;
            r_position_x[i] += r_velocity_x[i]     * time_step;
            r_position_y[i] += r_velocity_y[i]     * time_step;
            r_position_z[i] += r_velocity_z[i]     * time_step;
        }
    }
}

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