Simplify LLVM's APInt and APFloat for use in Subzero.

src/IceAPFloat.h

+//===-- subzero/src/IceAPFloat.h - Constant float conversions --*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file implements a class to represent Subzero float and double
+/// values.
+///
+/// Note: This is a simplified version of
+/// llvm/include/llvm/ADT/APFloat.h for use with Subzero.
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBZERO_SRC_ICEAPFLOAT_H
+#define SUBZERO_SRC_ICEAPFLOAT_H
+
+#include "IceAPInt.h"
+
+namespace Ice {
+
+/// Takes a 32-bit Int and converts it to the corresponding float value.
+inline float convertAPIntToFloat(const APInt &Int) {
+  assert(Int.getBitWidth() == 32);
+  union {
+    uint32_t IntValue;
+    float FloatValue;
+  } Converter;
+  Converter.IntValue = static_cast<uint32_t>(Int.getRawData());
+  return Converter.FloatValue;
+}
+
+/// Takes a 64-bit Int and converts it to the corresponding double value.

[Jim Stichnoth, 2014/12/12 21:54:15]

Consider reducing code duplication:

template<typename IntType, typename FpType>
inline FpType convertAPIntToFp(const APInt &Int) {
  static_assert(sizeof(IntType) == sizeof(FpType),
                "IntType and FpType should be the same width");
  assert(Int.getBitWidth() == sizeof(IntType) * CHAR_BIT);
  union {
    IntType IntValue;
    FpType FpValue;
  } Converter;
  Converter.IntValue = static_cast<IntType>(Int.getRawData());
  return Converter.FpValue;
}

[Karl, 2014/12/12 22:46:12]

Done.

+inline double convertAPIntToDouble(const APInt &Int) {
+  assert(Int.getBitWidth() == 64);
+  union {
+    uint64_t IntValue;
+    double DoubleValue;
+  } Converter;
+  Converter.IntValue = static_cast<uint64_t>(Int.getRawData());
+  return Converter.DoubleValue;
+}
+
+} // end of namespace Ice
+
+#endif //  SUBZERO_SRC_ICEAPFLOAT_H