[DAGCombiner] Match non-uniform constant vectors using predicates.
Most combines currently recognise scalar and splat-vector constants, but not non-uniform vector constants.
This patch introduces a matching mechanism that uses predicates to check against BUILD_VECTOR of ConstantSDNode, as well as scalar ConstantSDNode cases.
I've changed a couple of predicates to demonstrate - the combine-shl changes add currently unsupported cases, while the MatchRotate replaces an existing mechanism.
Differential Revision: https://reviews.llvm.org/D35492
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308598 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
