[SubZero] Fix f64 to/from i64 moves

crosstest/test_cast.h

 //===- subzero/crosstest/test_cast.h - Test prototypes ----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the function prototypes used for crosstesting cast
 // operations.
 //
 //===----------------------------------------------------------------------===//
 
 // The driver and the test program may be compiled by different
 // versions of clang, with different standard libraries that have
 // different definitions of int8_t.  Specifically, int8_t may be
 // typedef'd as either 'char' or 'signed char', which mangle to
 // different strings.  Avoid int8_t and use an explicit myint8_t.
 typedef signed char myint8_t;
 
 template <typename FromType, typename ToType> ToType cast(FromType a);
 template <typename FromType, typename ToType> ToType castBits(FromType a);
+
+// Targets like MIPS32, pass floating-point arguments in general purpose
+// registers when the first argument is passed in a general purpose register.
+// Overloaded cast and castBits functions take two extra integer argument to
+// check proper conversion of floating-point to/from general purpose registers.
+template <typename FromType, typename ToType> ToType cast(int i, FromType a,
+                                                          int j);
+template <typename FromType, typename ToType> ToType castBits(int i,
+                                                              FromType a,
+                                                              int j);