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Dramatically simplify building of natural loops and fix a bug where the BBMap

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was not correctly computed.

llvm-svn: 5606
This commit is contained in:
Chris Lattner 2003-02-22 21:33:11 +00:00
parent 1fc8307d2a
commit 4c2012352d
1 changed files with 24 additions and 38 deletions
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62
lib/Analysis/LoopInfo.cpp
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@ -60,6 +60,7 @@ void Loop::print(std::ostream &OS) const {
getSubLoops()[i]->print(OS);
}
//===----------------------------------------------------------------------===//
// LoopInfo implementation
//
@ -101,6 +102,12 @@ void LoopInfo::getAnalysisUsage(AnalysisUsage &AU) const {
void LoopInfo::print(std::ostream &OS) const {
for (unsigned i = 0; i < TopLevelLoops.size(); ++i)
TopLevelLoops[i]->print(OS);
#if 0
for (std::map<BasicBlock*, Loop*>::const_iterator I = BBMap.begin(),
E = BBMap.end(); I != E; ++I)
OS << "BB '" << I->first->getName() << "' level = "
<< I->second->LoopDepth << "\n";
#endif
}
Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
@ -132,45 +139,24 @@ Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
}
}
// Add the basic blocks that comprise this loop to the BBMap so that this
// loop can be found for them. Also check subsidary basic blocks to see if
// they start subloops of their own.
//
for (std::vector<BasicBlock*>::reverse_iterator I = L->Blocks.rbegin(),
E = L->Blocks.rend(); I != E; ++I)
// If there are any loops nested within this loop, create them now!
for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(),
E = L->Blocks.end(); I != E; ++I)
if (Loop *NewLoop = ConsiderForLoop(*I, DS)) {
L->SubLoops.push_back(NewLoop);
NewLoop->ParentLoop = L;
}
// Check to see if this block starts a new loop
if (*I != BB)
if (Loop *NewLoop = ConsiderForLoop(*I, DS)) {
L->SubLoops.push_back(NewLoop);
NewLoop->ParentLoop = L;
} else {
std::map<BasicBlock*, Loop*>::iterator BBMI = BBMap.lower_bound(*I);
if (BBMI == BBMap.end() || BBMI->first != *I) { // Not in map yet...
BBMap.insert(BBMI, std::make_pair(*I, L));
} else {
// If this is already in the BBMap then this means that we already
// added a loop for it, but incorrectly added the loop to a higher
// level loop instead of the current loop we are creating. Fix this
// now by moving the loop into the correct subloop.
//
Loop *SubLoop = BBMI->second;
if (SubLoop->getHeader() == *I) { // Only do this once for the loop...
Loop *OldSubLoopParent = SubLoop->getParentLoop();
if (OldSubLoopParent != L) {
// Remove SubLoop from OldSubLoopParent's list of subloops...
std::vector<Loop*>::iterator I =
std::find(OldSubLoopParent->SubLoops.begin(),
OldSubLoopParent->SubLoops.end(), SubLoop);
assert(I != OldSubLoopParent->SubLoops.end()
&& "Loop parent doesn't contain loop?");
OldSubLoopParent->SubLoops.erase(I);
SubLoop->ParentLoop = L;
L->SubLoops.push_back(SubLoop);
}
}
}
}
// Add the basic blocks that comprise this loop to the BBMap so that this
// loop can be found for them.
//
for (std::vector<BasicBlock*>::iterator I = L->Blocks.begin(),
E = L->Blocks.end(); I != E; ++I) {
std::map<BasicBlock*, Loop*>::iterator BBMI = BBMap.lower_bound(*I);
if (BBMI == BBMap.end() || BBMI->first != *I) // Not in map yet...
BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
}
return L;
}