[InstCombine] Fix extractelement use before def

This fixes a bug that can cause extractelements with operands that
haven't been defined yet to be inserted at a wrong point when
optimising insertelements.

Patch by Karl Hylen.

Differential Revision: https://reviews.llvm.org/D33449


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304701 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed