The implication logic for two values that are both negative or non-negative
says that it doesn't matter whether their predicate is signed and unsigned,
but only flips unsigned into signed for further inference. This patch adds
support for flipping a signed predicate into unsigned as well.
Differential Revision: https://reviews.llvm.org/D109959
Reviewed By: nikic
There is a piece of logic that uses the fact that signed and unsigned
versions of the same predicate are equivalent when both values are
non-negative. It's also true when both of them are negative.
Differential Revision: https://reviews.llvm.org/D109957
Reviewed By: nikic
