[GlobalISel] Add a G_FRINT opcode

Equivalent to SelectionDAG's frint node.

Differential Revision: https://reviews.llvm.org/D60891

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358785 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed