Hi Richard, > Maybe pre-existing, but are ordered comparisons safe for the > ZERO_EXTRACT case? If we extract the top 8 bits (say), zero extend, > and compare with zero, the result should be >= 0, whereas TST would > set N to the top bit.
Yes in principle zero extract should always be positive assuming we never extract all bits (= nop). GCC never generates a zero extend of the top bits (it becomes a shift), so I don't think it can be generated. However I'll change it to use CC_Z in the commit since signed comparisons of zero extend seem to be folded to equality (or true/false), so there is no point in supporting anything but equality comparisons anyway. Cheers, Wilco
