[RISCV] Codegen support for RV32D floating point conversion operations

This also includes support and a test for truncating stores, which are now
possible thanks to the fpround pattern.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329876 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed