Subzero. Changes the Register Allocator so that it is aware of register
aliases.

BUG=
R=jvoung@chromium.org, stichnot@chromium.org

Review URL: https://codereview.chromium.org/1319203005.

src/IceTargetLowering.h

diff --git a/src/IceTargetLowering.h b/src/IceTargetLowering.h
index a1c5aad..e63ece2 100644
--- a/src/IceTargetLowering.h
+++ b/src/IceTargetLowering.h
@@ -211,6 +211,8 @@
   virtual llvm::SmallBitVector getRegisterSet(RegSetMask Include,
                                               RegSetMask Exclude) const = 0;
   virtual const llvm::SmallBitVector &getRegisterSetForType(Type Ty) const = 0;
+  virtual const llvm::SmallBitVector &getAliasesForRegister(SizeT) const = 0;
+
   void regAlloc(RegAllocKind Kind);
 
   virtual void