[SLPVectorizer] Fix dependency list
[SLPVectorizer] Fix dependency list

Summary:
DemandedBits was added to the requirements of SLPVectorizer in rL261212
(and various earlier version of it), but the appropriate initialization
statement was accidentally forgotten.

Ref [[ https://github.com/JuliaLang/julia/issues/14998 | JuliaLang/julia#14998 ]].

Patch by Yichao Yu.
Reviewers: mssimpso
Differential Revision: http://reviews.llvm.org/D18152

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@263476 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm