Add MachineLoopRanges analysis.

A MachineLoopRange contains the intervals of slot indexes covered by the blocks
in a loop. This representation of the loop blocks is more efficient to compare
against interfering registers during register coalescing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121917 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/MachineLoopRanges.h

@@ -0,0 +1,84 @@
+//===- MachineLoopRanges.h - Ranges of machine loops -----------*- c++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides the interface to the MachineLoopRanges analysis.
+//
+// Provide on-demand information about the ranges of machine instructions
+// covered by a loop.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_MACHINELOOPRANGES_H
+#define LLVM_CODEGEN_MACHINELOOPRANGES_H
+
+#include "llvm/ADT/IntervalMap.h"
+#include "llvm/CodeGen/SlotIndexes.h"
+
+namespace llvm {
+
+class MachineLoop;
+class MachineLoopInfo;
+class raw_ostream;
+
+/// MachineLoopRange - Range information for a single loop.
+class MachineLoopRange {
+  friend class MachineLoopRanges;
+  typedef IntervalMap<SlotIndex, unsigned, 4> RangeMap;
+  typedef RangeMap::Allocator Allocator;
+
+  /// The mapped loop.
+  const MachineLoop *const Loop;
+
+  /// Map intervals to a bit mask.
+  /// Bit 0 = inside loop block.
+  RangeMap Intervals;
+
+  /// Create a MachineLoopRange, only accessible to MachineLoopRanges.
+  MachineLoopRange(const MachineLoop*, Allocator&, SlotIndexes&);
+
+public:
+  /// overlaps - Return true if this loop overlaps the given range of machine
+  /// inteructions.
+  bool overlaps(SlotIndex Start, SlotIndex Stop);
+
+  /// print - Print loop ranges on OS.
+  void print(raw_ostream&) const;
+};
+
+raw_ostream &operator<<(raw_ostream&, const MachineLoopRange&);
+
+/// MachineLoopRanges - Analysis pass that provides on-demand per-loop range
+/// information.
+class MachineLoopRanges : public MachineFunctionPass {
+  typedef DenseMap<const MachineLoop*, MachineLoopRange*> CacheMap;
+  typedef MachineLoopRange::Allocator MapAllocator;
+
+  MapAllocator Allocator;
+  SlotIndexes *Indexes;
+  CacheMap Cache;
+
+public:
+  static char ID; // Pass identification, replacement for typeid
+
+  MachineLoopRanges() : MachineFunctionPass(ID), Indexes(0) {}
+  ~MachineLoopRanges() { releaseMemory(); }
+
+  /// getLoopRange - Return the range of loop.
+  MachineLoopRange *getLoopRange(const MachineLoop *Loop);
+
+private:
+  virtual bool runOnMachineFunction(MachineFunction&);
+  virtual void releaseMemory();
+  virtual void getAnalysisUsage(AnalysisUsage&) const;
+};
+
+
+} // end namespace llvm
+
+#endif // LLVM_CODEGEN_MACHINELOOPRANGES_H

include/llvm/CodeGen/Passes.h

@@ -45,6 +45,11 @@ namespace llvm {
   ///
   extern char &MachineLoopInfoID;
 
+  /// MachineLoopRanges pass - This pass is an on-demand loop coverage
+  /// analysis pass.
+  ///
+  extern char &MachineLoopRangesID;
+
   /// MachineDominators pass - This pass is a machine dominators analysis pass.
   ///
   extern char &MachineDominatorsID;