message: Translate free() nofree as unreachable
diff: @@ -41,6 +41,10 @@ known_call(llvm::CallInst &i, const llvm::TargetLibraryInfo &TLI,
  } else if (llvm::isReallocLikeFn(&i, &TLI, false)) {
  RETURN_VAL(make_unique<Malloc>(*ty, value_name(i), *args[0], *args[1]));
  } else if (llvm::isFreeCall(&i, &TLI)) {
  + if (i.hasFnAttr(llvm::Attribute::NoFree)) {
  + auto zero = make_intconst(0, 1);
  + RETURN_VAL(make_unique<Assume>(*zero, Assume::AndNonPoison));
  + }
  RETURN_VAL(make_unique<Free>(*args[0]));
  }
  