commit d88990b02834a85e23d8bcaa212b2006748d29b2
author Simon Pilgrim <llvm-dev@redking.me.uk> Thu Sep 08 12:57:51 2016 +0000
committer Simon Pilgrim <llvm-dev@redking.me.uk> Thu Sep 08 12:57:51 2016 +0000
tree 43c2ed12ad8b97c84214b9ffaa50a8585d09c7a2
parent 707719e6254120891ffe2e509ca68896e0fbf292

[SelectionDAG] Add BUILD_VECTOR support to computeKnownBits and SimplifyDemandedBits

Add the ability to computeKnownBits and SimplifyDemandedBits to extract the known zero/one bits from BUILD_VECTOR, returning the known bits that are shared by every vector element.

This is an initial step towards determining the sign bits of a vector (PR29079).

Differential Revision: https://reviews.llvm.org/D24253

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280927 91177308-0d34-0410-b5e6-96231b3b80d8