This is intended to improve code generation for GEPs, as the index value is
shifted by the element size and in GEPs of multi-dimensional arrays the index
of higher dimensions is multiplied by the lower dimension size.
Differential Revision: http://reviews.llvm.org/D12197
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245689 91177308-0d34-0410-b5e6-96231b3b80d8