[mips] Support shrink-wrapping

Except for -O0, it's enabled by default.

Patch by Vladimir Stefanovic.

Differential Revision: https://reviews.llvm.org/D47947


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335989 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed