1 //===-- InterferenceCache.h - Caching per-block interference ---*- C++ -*--===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // InterferenceCache remembers per-block interference in LiveIntervalUnions.
12 //===----------------------------------------------------------------------===//
14 #define DEBUG_TYPE "regalloc"
15 #include "InterferenceCache.h"
16 #include "llvm/Target/TargetRegisterInfo.h"
20 void InterferenceCache::init(MachineFunction *mf,
21 LiveIntervalUnion *liuarray,
23 const TargetRegisterInfo *tri) {
27 PhysRegEntries.assign(TRI->getNumRegs(), 0);
28 for (unsigned i = 0; i != CacheEntries; ++i)
29 Entries[i].clear(mf, indexes);
32 InterferenceCache::Entry *InterferenceCache::get(unsigned PhysReg) {
33 unsigned E = PhysRegEntries[PhysReg];
34 if (E < CacheEntries && Entries[E].getPhysReg() == PhysReg) {
35 if (!Entries[E].valid(LIUArray, TRI))
36 Entries[E].revalidate();
39 // No valid entry exists, pick the next round-robin entry.
41 if (++RoundRobin == CacheEntries)
43 Entries[E].reset(PhysReg, LIUArray, TRI, MF);
44 PhysRegEntries[PhysReg] = E;
48 /// revalidate - LIU contents have changed, update tags.
49 void InterferenceCache::Entry::revalidate() {
50 // Invalidate all block entries.
52 // Invalidate all iterators.
53 PrevPos = SlotIndex();
54 for (unsigned i = 0, e = Aliases.size(); i != e; ++i)
55 Aliases[i].second = Aliases[i].first->getTag();
58 void InterferenceCache::Entry::reset(unsigned physReg,
59 LiveIntervalUnion *LIUArray,
60 const TargetRegisterInfo *TRI,
61 const MachineFunction *MF) {
62 // LIU's changed, invalidate cache.
65 Blocks.resize(MF->getNumBlockIDs());
67 for (const unsigned *AS = TRI->getOverlaps(PhysReg); *AS; ++AS) {
68 LiveIntervalUnion *LIU = LIUArray + *AS;
69 Aliases.push_back(std::make_pair(LIU, LIU->getTag()));
73 PrevPos = SlotIndex();
74 unsigned e = Aliases.size();
76 for (unsigned i = 0; i != e; ++i)
77 Iters[i].setMap(Aliases[i].first->getMap());
80 bool InterferenceCache::Entry::valid(LiveIntervalUnion *LIUArray,
81 const TargetRegisterInfo *TRI) {
82 unsigned i = 0, e = Aliases.size();
83 for (const unsigned *AS = TRI->getOverlaps(PhysReg); *AS; ++AS, ++i) {
84 LiveIntervalUnion *LIU = LIUArray + *AS;
85 if (i == e || Aliases[i].first != LIU)
87 if (LIU->changedSince(Aliases[i].second))
93 void InterferenceCache::Entry::update(unsigned MBBNum) {
94 SlotIndex Start, Stop;
95 tie(Start, Stop) = Indexes->getMBBRange(MBBNum);
97 // Use advanceTo only when possible.
98 if (PrevPos != Start) {
99 if (!PrevPos.isValid() || Start < PrevPos)
100 for (unsigned i = 0, e = Iters.size(); i != e; ++i)
101 Iters[i].find(Start);
103 for (unsigned i = 0, e = Iters.size(); i != e; ++i)
104 Iters[i].advanceTo(Start);
108 MachineFunction::const_iterator MFI = MF->getBlockNumbered(MBBNum);
109 BlockInterference *BI = &Blocks[MBBNum];
112 BI->First = BI->Last = SlotIndex();
114 // Check for first interference.
115 for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
119 SlotIndex StartI = I.start();
122 if (!BI->First.isValid() || StartI < BI->First)
127 if (BI->First.isValid())
130 // No interference in this block? Go ahead and precompute the next block.
131 if (++MFI == MF->end())
133 MBBNum = MFI->getNumber();
134 BI = &Blocks[MBBNum];
137 tie(Start, Stop) = Indexes->getMBBRange(MBBNum);
140 // Check for last interference in block.
141 for (unsigned i = 0, e = Iters.size(); i != e; ++i) {
143 if (!I.valid() || I.start() >= Stop)
146 bool Backup = !I.valid() || I.start() >= Stop;
149 SlotIndex StopI = I.stop();
150 if (!BI->Last.isValid() || StopI > BI->Last)