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Remove LazyLiveness from the tree. It doesn't work right now, and I'm not going to have the time

to finish it any time soon.  If someone's interested it, they can resurrect it from SVN history.

llvm-svn: 83480
This commit is contained in:
Owen Anderson 2009-10-07 18:40:17 +00:00
parent 9bb47b3e5d
commit 132727997c

View File

@ -1,168 +0,0 @@
//===- LazyLiveness.cpp - Lazy, CFG-invariant liveness information --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass implements a lazy liveness analysis as per "Fast Liveness Checking
// for SSA-form Programs," by Boissinot, et al.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "lazyliveness"
#include "llvm/CodeGen/LazyLiveness.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"
using namespace llvm;
char LazyLiveness::ID = 0;
static RegisterPass<LazyLiveness> X("lazy-liveness", "Lazy Liveness Analysis");
void LazyLiveness::computeBackedgeChain(MachineFunction& mf,
MachineBasicBlock* MBB) {
SparseBitVector<128> tmp = rv[MBB];
tmp.set(preorder[MBB]);
tmp &= backedge_source;
calculated.set(preorder[MBB]);
for (SparseBitVector<128>::iterator I = tmp.begin(); I != tmp.end(); ++I) {
assert(rev_preorder.size() > *I && "Unknown block!");
MachineBasicBlock* SrcMBB = rev_preorder[*I];
for (MachineBasicBlock::succ_iterator SI = SrcMBB->succ_begin(),
SE = SrcMBB->succ_end(); SI != SE; ++SI) {
MachineBasicBlock* TgtMBB = *SI;
if (backedges.count(std::make_pair(SrcMBB, TgtMBB)) &&
!rv[MBB].test(preorder[TgtMBB])) {
if (!calculated.test(preorder[TgtMBB]))
computeBackedgeChain(mf, TgtMBB);
tv[MBB].set(preorder[TgtMBB]);
SparseBitVector<128> right = tv[TgtMBB];
tv[MBB] |= right;
}
}
tv[MBB].reset(preorder[MBB]);
}
}
bool LazyLiveness::runOnMachineFunction(MachineFunction &mf) {
rv.clear();
tv.clear();
backedges.clear();
backedge_source.clear();
backedge_target.clear();
calculated.clear();
preorder.clear();
rev_preorder.clear();
rv.resize(mf.size());
tv.resize(mf.size());
preorder.resize(mf.size());
rev_preorder.reserve(mf.size());
MRI = &mf.getRegInfo();
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
// Step 0: Compute preorder numbering for all MBBs.
unsigned num = 0;
for (df_iterator<MachineDomTreeNode*> DI = df_begin(MDT.getRootNode()),
DE = df_end(MDT.getRootNode()); DI != DE; ++DI) {
preorder[(*DI)->getBlock()] = num++;
rev_preorder.push_back((*DI)->getBlock());
}
// Step 1: Compute the transitive closure of the CFG, ignoring backedges.
for (po_iterator<MachineBasicBlock*> POI = po_begin(&*mf.begin()),
POE = po_end(&*mf.begin()); POI != POE; ++POI) {
MachineBasicBlock* MBB = *POI;
SparseBitVector<128>& entry = rv[MBB];
entry.set(preorder[MBB]);
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end(); SI != SE; ++SI) {
DenseMap<MachineBasicBlock*, SparseBitVector<128> >::iterator SII =
rv.find(*SI);
// Because we're iterating in postorder, any successor that does not yet
// have an rv entry must be on a backedge.
if (SII != rv.end()) {
entry |= SII->second;
} else {
backedges.insert(std::make_pair(MBB, *SI));
backedge_source.set(preorder[MBB]);
backedge_target.set(preorder[*SI]);
}
}
}
for (SparseBitVector<128>::iterator I = backedge_source.begin();
I != backedge_source.end(); ++I)
computeBackedgeChain(mf, rev_preorder[*I]);
for (po_iterator<MachineBasicBlock*> POI = po_begin(&*mf.begin()),
POE = po_end(&*mf.begin()); POI != POE; ++POI)
if (!backedge_target.test(preorder[*POI]))
for (MachineBasicBlock::succ_iterator SI = (*POI)->succ_begin(),
SE = (*POI)->succ_end(); SI != SE; ++SI)
if (!backedges.count(std::make_pair(*POI, *SI)) && tv.count(*SI)) {
SparseBitVector<128> right = tv[*SI];
tv[*POI] |= right;
}
for (po_iterator<MachineBasicBlock*> POI = po_begin(&*mf.begin()),
POE = po_end(&*mf.begin()); POI != POE; ++POI)
tv[*POI].set(preorder[*POI]);
return false;
}
bool LazyLiveness::vregLiveIntoMBB(unsigned vreg, MachineBasicBlock* MBB) {
MachineDominatorTree& MDT = getAnalysis<MachineDominatorTree>();
MachineBasicBlock* DefMBB = MRI->def_begin(vreg)->getParent();
unsigned def = preorder[DefMBB];
unsigned max_dom = 0;
for (df_iterator<MachineDomTreeNode*> DI = df_begin(MDT[DefMBB]),
DE = df_end(MDT[DefMBB]); DI != DE; ++DI) {
if (preorder[DI->getBlock()] > max_dom) {
max_dom = preorder[(*DI)->getBlock()];
}
}
if (preorder[MBB] <= def || max_dom < preorder[MBB])
return false;
SparseBitVector<128>::iterator I = tv[MBB].begin();
while (I != tv[MBB].end() && *I <= def) ++I;
while (I != tv[MBB].end() && *I < max_dom) {
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(vreg),
UE = MachineRegisterInfo::use_end(); UI != UE; ++UI) {
MachineBasicBlock* UseMBB = UI->getParent();
if (rv[rev_preorder[*I]].test(preorder[UseMBB]))
return true;
unsigned t_dom = 0;
for (df_iterator<MachineDomTreeNode*> DI =
df_begin(MDT[rev_preorder[*I]]), DE = df_end(MDT[rev_preorder[*I]]);
DI != DE; ++DI)
if (preorder[DI->getBlock()] > t_dom) {
max_dom = preorder[(*DI)->getBlock()];
}
I = tv[MBB].begin();
while (I != tv[MBB].end() && *I < t_dom) ++I;
}
}
return false;
}