[SLPVectorizer] Replace VL[0] to VL0 with assert, add propagateIRFlags extra parameter VL0, 
                replace E->Scalars[0] to VL0, NFCI.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@310904 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed