Subzero: Refactor x86 register representation to actively use aliases.

src/IceTargetLoweringX86RegClass.h

+//===- subzero/src/IceTargetLoweringX86RegClass.h - x86 reg class -*- C++ -*-=//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file declares the X86 register class extensions.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef SUBZERO_SRC_ICETARGETLOWERINGX86REGCLASS_H
+#define SUBZERO_SRC_ICETARGETLOWERINGX86REGCLASS_H
+
+#include "IceOperand.h" // RC_Target
+
+namespace Ice {
+namespace X86Internal {
+
+// Extend enum RegClass with x86-specific register classes.
+enum RegClassX86 : uint8_t {
+  RCX86_Is64To8 = RC_Target,

[John, 2015/11/09 16:23:30]

optinal: comment each class?

[Jim Stichnoth, 2015/11/09 18:45:35]

Done.

+  RCX86_Is32To8,
+  RCX86_Is16To8,
+  RCX86_IsTrunc8Rcvr,
+  RCX86_IsAhRcvr,
+  RCX86_NUM
+};
+
+} // end of namespace X86Internal
+} // end of namespace Ice
+
+#endif // SUBZERO_SRC_ICETARGETLOWERINGX86REGCLASS_H