[LVI] Improve select handling to use condition
This patches teaches LVI to recognize clamp idioms (e.g. select(a > 5, a, 5) will always produce something greater than 5.
The tests end up being somewhat simplistic because trying to exercise the case I actually care about (a loop with a range check on a clamped secondary induction variable) ends up tripping across a couple of other imprecisions in the analysis. Ah, the joys of LVI...
Differential Revision: http://reviews.llvm.org/D16827
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@260627 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed