Clean up implementation reading literal constants.

src/IceAPInt.h

-//===-- subzero/src/IceAPInt.h - Constant integer 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 64 bit integer constant
-/// values, and their conversion to variable bit sized integers.
-///
-/// Note: This is a simplified version of llvm/include/llvm/ADT/APInt.h for use
-/// with Subzero.
-//===----------------------------------------------------------------------===//
-
-#ifndef SUBZERO_SRC_ICEAPINT_H
-#define SUBZERO_SRC_ICEAPINT_H
-
-#include "IceDefs.h"
-
-namespace Ice {
-
-class APInt {
-  APInt() = delete;
-  APInt(const APInt &) = delete;
-  APInt &operator=(const APInt &) = delete;
-
-public:
-  /// Bits in an (internal) value.
-  static const SizeT APINT_BITS_PER_WORD = sizeof(uint64_t) * CHAR_BIT;
-
-  APInt(SizeT Bits, uint64_t Val) : BitWidth(Bits), Val(Val) {
-    assert(Bits && "bitwidth too small");
-    assert(Bits <= APINT_BITS_PER_WORD && "bitwidth too big");
-    clearUnusedBits();
-  }
-
-  uint32_t getBitWidth() const { return BitWidth; }
-
-  int64_t getSExtValue() const {
-    return static_cast<int64_t>(Val << (APINT_BITS_PER_WORD - BitWidth)) >>
-           (APINT_BITS_PER_WORD - BitWidth);
-  }
-
-  uint64_t getRawData() const { return Val; }
-
-private:
-  uint32_t BitWidth; /// The number of bits in this APInt.
-  uint64_t Val;      /// The (64-bit) equivalent integer value.
-
-  /// Clear unused high order bits.
-  void clearUnusedBits() {
-    // If all bits are used, we want to leave the value alone.
-    if (BitWidth == APINT_BITS_PER_WORD)
-      return;
-
-    // Mask out the high bits.
-    Val &= ~static_cast<uint64_t>(0) >> (APINT_BITS_PER_WORD - BitWidth);
-  }
-};
-
-} // end of namespace Ice
-
-#endif // SUBZERO_SRC_ICEAPINT_H