[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 [[ JuliaLang/julia#14998 | JuliaLang/julia#14998 ]].

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263476 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -4575,6 +4575,7 @@ INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
+INITIALIZE_PASS_DEPENDENCY(DemandedBits)
 INITIALIZE_PASS_END(SLPVectorizer, SV_NAME, lv_name, false, false)
 
 namespace llvm {