[RISCV] Add codegen for RV32F floating point load/store

As part of this, add support for load/store from the constant pool. This is
used to materialise f32 constants.

llvm-svn: 327979
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.h b/llvm/lib/Target/RISCV/RISCVISelLowering.h
index 6fbe2dd..101fd6e 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.h
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.h
@@ -83,6 +83,7 @@
   }
   SDValue lowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
+  SDValue lowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerExternalSymbol(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerSELECT(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerVASTART(SDValue Op, SelectionDAG &DAG) const;