[ARM] Add OptMinSize to ARMSubtarget
In many places in the backend, we like to know whether we're
optimising for code size and this is performed by checking the
current machine function attributes. A subtarget is created on a
per-function basis, so it's possible to know when we're compiling for
code size on construction so record this in the new object.

Differential Revision: https://reviews.llvm.org/D57812

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@353501 91177308-0d34-0410-b5e6-96231b3b80d8
15 files changed