#2458 shift operation gives incorrect error and emits bad code

[Peter Dons Tychsen]

Hello SDCC team,

Found this in some of my code:

uint32_t global;
void func(void)
{
  uint8_t i=18;
  uint8_t bit;

  bit = (BOOL)((global & (((uint32_t)1) << i)) && TRUE);
  if(bit)
  {
      while(1);
  }

Compiling this gives: "unreachable code"

The reason is the "i" variable which is only 8 bit. However, as the "1" is already casted, this should not matter.

What is worse, if the "i" variable is not a constant (e.g. comes from a function call), the code can build, but bad code is emitted. All bits above 8 are broken.

I think there are some general rules for casts that do not work here.

Thanks,

/pedro

[Ben Shi]

Thanks to Peter's patch and Philipp' help. :)