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f2c6e367c1
The spillers can pluck the analyses they need from the pass reference. Switch some never-null pointers to references. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108969 91177308-0d34-0410-b5e6-96231b3b80d8
121 lines
3.9 KiB
C++
121 lines
3.9 KiB
C++
//===---------- SplitKit.cpp - Toolkit for splitting live ranges ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the SplitAnalysis class as well as mutator functions for
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// live range splitting.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/DenseMap.h"
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namespace llvm {
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class LiveInterval;
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class LiveIntervals;
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class MachineBasicBlock;
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class MachineInstr;
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class MachineFunction;
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class MachineFunctionPass;
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class MachineLoop;
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class MachineLoopInfo;
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class TargetInstrInfo;
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class SplitAnalysis {
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const MachineFunction &mf_;
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const LiveIntervals &lis_;
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const MachineLoopInfo &loops_;
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const TargetInstrInfo &tii_;
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// Current live interval.
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const LiveInterval *curli_;
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// Instructions using the the current register.
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typedef SmallPtrSet<const MachineInstr*, 16> InstrPtrSet;
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InstrPtrSet usingInstrs_;
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// The number of instructions using curli in each basic block.
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typedef DenseMap<const MachineBasicBlock*, unsigned> BlockCountMap;
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BlockCountMap usingBlocks_;
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// Loops where the curent interval is used.
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typedef SmallPtrSet<const MachineLoop*, 16> LoopPtrSet;
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LoopPtrSet usingLoops_;
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// Sumarize statistics by counting instructions using curli_.
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void analyzeUses();
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/// canAnalyzeBranch - Return true if MBB ends in a branch that can be
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/// analyzed.
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bool canAnalyzeBranch(const MachineBasicBlock *MBB);
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public:
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SplitAnalysis(const MachineFunction &mf, const LiveIntervals &lis,
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const MachineLoopInfo &mli);
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/// analyze - set curli to the specified interval, and analyze how it may be
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/// split.
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void analyze(const LiveInterval *li);
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/// clear - clear all data structures so SplitAnalysis is ready to analyze a
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/// new interval.
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void clear();
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typedef SmallPtrSet<const MachineBasicBlock*, 16> BlockPtrSet;
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// Sets of basic blocks surrounding a machine loop.
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struct LoopBlocks {
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BlockPtrSet Loop; // Blocks in the loop.
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BlockPtrSet Preds; // Loop predecessor blocks.
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BlockPtrSet Exits; // Loop exit blocks.
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void clear() {
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Loop.clear();
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Preds.clear();
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Exits.clear();
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}
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};
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// Calculate the block sets surrounding the loop.
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void getLoopBlocks(const MachineLoop *Loop, LoopBlocks &Blocks);
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/// LoopPeripheralUse - how is a variable used in and around a loop?
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/// Peripheral blocks are the loop predecessors and exit blocks.
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enum LoopPeripheralUse {
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ContainedInLoop, // All uses are inside the loop.
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SinglePeripheral, // At most one instruction per peripheral block.
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MultiPeripheral, // Multiple instructions in some peripheral blocks.
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OutsideLoop // Uses outside loop periphery.
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};
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/// analyzeLoopPeripheralUse - Return an enum describing how curli_ is used in
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/// and around the Loop.
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LoopPeripheralUse analyzeLoopPeripheralUse(const LoopBlocks&);
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/// getCriticalExits - It may be necessary to partially break critical edges
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/// leaving the loop if an exit block has phi uses of curli. Collect the exit
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/// blocks that need special treatment into CriticalExits.
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void getCriticalExits(const LoopBlocks &Blocks, BlockPtrSet &CriticalExits);
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/// canSplitCriticalExits - Return true if it is possible to insert new exit
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/// blocks before the blocks in CriticalExits.
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bool canSplitCriticalExits(const LoopBlocks &Blocks,
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BlockPtrSet &CriticalExits);
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/// getBestSplitLoop - Return the loop where curli may best be split to a
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/// separate register, or NULL.
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const MachineLoop *getBestSplitLoop();
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};
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/// splitAroundLoop - Try to split curli into a separate live interval inside
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/// the loop. Retun true on success.
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bool splitAroundLoop(SplitAnalysis&, const MachineLoop*);
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}
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