Error: Asm: 16 or 32 bit references not supported

Optimization level O3 or higher

var
  b: boolean;
  w: word;

begin
  b := (w shr 1) <> 0;
  w := w shl 1; // project1.lpr(7,3) Error: Asm: 16 or 32 bit references not supported
  if b then w := w xor 1;
end.