We already do this for min/max (see the blob above the diff),
so we should do the same for abs/nabs.
A sign-bit check (<s 0) is used as a predicate for other IR
transforms and it's likely the best for codegen.
This might solve the motivating cases for D47037 and D47041,
but I think those patches still make sense. We can't guarantee
this canonicalization if the icmp has more than one use.
Differential Revision: https://reviews.llvm.org/D47076
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332819 91177308-0d34-0410-b5e6-96231b3b80d8
Sanjay Patel
42ebf193bc