RE: Unsigned widening casts of binary "not" operations..

quoted

If the narrower type is signed it is probably even more confusing!
The high bits will be preserved unless you are masking off bit 31.

Yes. However, that case doesn't trigger with the normal case of small
values. So "~4" works fine with widening, in a way that "~4u" does
not.

Thinks ... converting:
	foo &= ~bar;
to:
	foo = ~(~foo | bar);
would generally DTRT.
Whether the compiler has the relevant patterns to optimise
it is another question.

	David