Adds a MachineFunctionPass that scans the body to find calls, and
update the register mask with the one saved by the
RegUsageInfoCollector analysis in PhysicalRegisterUsageInfo.
Patch by Vivek Pandya <vivekvpandya@gmail.com>
Differential Revision: http://reviews.llvm.org/D21180
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272414 91177308-0d34-0410-b5e6-96231b3b80d8
