Erik,

1) I tried to turn your code into something compilable and got two warnings from evelyn at the if-statements around the switch since my switch was empty. Do you have empty clauses in there too? It is another reason for evelyn to bark.

__bit GBtgLvl;
char GCtgOsc, GCmeasureState;
__sbit __at(0x90) SB_P1_SQWOUT;

void test(void)
{
  if (!GCtgOsc)
  { // reload 60Hz timer
    GCtgOsc = 10;
    GBtgLvl = !GBtgLvl;
    SB_P1_SQWOUT = GBtgLvl; // change 60Hz state P1.0  
  }
  
  if (GBtgLvl)                ////// EVELYN BARKS HERE
  {
    if  (GCtgOsc == 1)        ////// AND HERE
    { // output is positive
      switch (GCmeasureState) ////// BUT NOT HERE
      {
      default:
        break;
      }
    }
  }
}
 

2) And I'm not sure what exactly you're searching for and therefor cannot give a good keyword. Maybe it's W_CONTROL_FLOW? Besides this warning is marked pedantic and thus can also be suppressed with --less-pedantic.

Maarten