On Mon, Apr 16, 2018 at 09:26:13AM -0700, Carl Love wrote: > > But then the & ~0x1f test is not good either, it does not work for > > values > > -16..-1 ? > > > > You cannot handle signed and unsigned exactly the same for the test > > for > > allowed values.
> The test > > if (TREE_CODE (arg0) != INTEGER_CST > || TREE_INT_CST_LOW (arg0) & ~0x1f) > return false; > > is really checking if the value is not an integer or the value is not a > 5-bit constant. It seems to me this should work fine for signed and > unsigned 5-bit numbers. All negative numbers (-16..-1 here) have bits outside 0x1f set (all bits outside it). Segher
