[GlobalISel][X86] Fold FI/G_GEP into LDR/STR instruction addressing mode.

Summary: Implement some of the simplest addressing modes.It should help to test ABI.

Reviewers: zvi, guyblank

Reviewed By: guyblank

Subscribers: rovka, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D33888

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305691 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed