[RISCV] Codegen support for RV32F floating point comparison operations

This patch also includes extensive tests targeted at select and br+fcmp IR
inputs. A sequence of br+fcmp required support for FPR32 registers to be added
to RISCVInstrInfo::storeRegToStackSlot and
RISCVInstrInfo::loadRegFromStackSlot.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@328104 91177308-0d34-0410-b5e6-96231b3b80d8
8 files changed