One that I recall that I'm hoping still applies is having a syntactically and conceptually lightweight way to express semantically parallel computation logic. Given the code:

  junction1 = val1 | val2 | val3;
  junction2 = val4 & val5;
  if junction1 op junction2 { ... };

the compiler is free to fire off several threads, or set up a lower level SIMD parallel process, with short-circuiting, to compute the conditional result.