getCompare returns true, false or undef constants if the comparison can
be evaluated, or nullptr if it cannot. This is in line with what
ConstantExpr::getCompare returns. It also allows us to use
ConstantExpr::getCompare for comparing constants.
Reviewers: davide, mssimpso, dberlin, anna
Reviewed By: davide
Differential Revision: https://reviews.llvm.org/D43761
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@326720 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This allows sharing the lattice value code between LVI and SCCP (D36656).
It also adds a `satisfiesPredicate` function, used by D36656.
Reviewers: davide, sanjoy, efriedma
Reviewed By: sanjoy
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D37591
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314411 91177308-0d34-0410-b5e6-96231b3b80d8
