[GlobalMerge] Allow merging globals with arbitrary alignment.

Instead of depending on implicit padding from the structure layout code,
use a packed struct and emit the padding explicitly.

Differential Revision: https://reviews.llvm.org/D49710



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337961 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed