Subzero: Register allocator performance improvements and simplifications.

src/IceRegAlloc.h

 //===- subzero/src/IceRegAlloc.h - Linear-scan reg. allocation --*- 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 data structures used during linear-scan
-// register allocation.  This includes LiveRangeWrapper which
-// encapsulates a variable and its live range, and LinearScan which
-// holds the various work queues for the linear-scan algorithm.
+// This file declares the LinearScan data structure used during
+// linear-scan register allocation, which holds the various work
+// queues for the linear-scan algorithm.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEREGALLOC_H
 #define SUBZERO_SRC_ICEREGALLOC_H
 
 #include "IceDefs.h"
 #include "IceTypes.h"
 
 namespace Ice {
 
-// Currently this just wraps a Variable pointer, so in principle we
-// could use containers of Variable* instead of LiveRangeWrapper.  But
-// in the future, we may want to do more complex things such as live
-// range splitting, and keeping a wrapper should make that simpler.
-class LiveRangeWrapper {
-public:
-  LiveRangeWrapper(Variable *Var) : Var(Var) {}
-  const LiveRange &range() const { return Var->getLiveRange(); }
-  bool endsBefore(const LiveRangeWrapper &Other) const {
-    return range().endsBefore(Other.range());
-  }
-  bool overlaps(const LiveRangeWrapper &Other) const {
-    const bool UseTrimmed = true;
-    return range().overlaps(Other.range(), UseTrimmed);
-  }
-  bool overlapsStart(const LiveRangeWrapper &Other) const {
-    const bool UseTrimmed = true;
-    return range().overlapsInst(Other.range().getStart(), UseTrimmed);
-  }
-  Variable *Var;
-  void dump(const Cfg *Func) const;
+class LinearScan {
+  LinearScan(const LinearScan &) = delete;
+  LinearScan &operator=(const LinearScan &) = delete;
 
-private:
-  // LiveRangeWrapper(const LiveRangeWrapper &) = delete;
-  // LiveRangeWrapper &operator=(const LiveRangeWrapper &) = delete;
-};
-
-class LinearScan {
 public:
   LinearScan(Cfg *Func) : Func(Func) {}
   void scan(const llvm::SmallBitVector &RegMask);
   void dump(Cfg *Func) const;
 
 private:
   Cfg *const Func;
-  typedef std::vector<LiveRangeWrapper> OrderedRanges;
-  typedef std::list<LiveRangeWrapper> UnorderedRanges;
+  typedef std::vector<Variable *> OrderedRanges;
+  typedef std::list<Variable *> UnorderedRanges;
   OrderedRanges Unhandled;
   // UnhandledPrecolored is a subset of Unhandled, specially collected
   // for faster processing.
   OrderedRanges UnhandledPrecolored;
   UnorderedRanges Active, Inactive, Handled;
-  LinearScan(const LinearScan &) = delete;
-  LinearScan &operator=(const LinearScan &) = delete;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEREGALLOC_H