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- LoopInfo now calculates and tracks loop exit blocks

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5650 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-02-27 00:38:34 +00:00
parent fe3ae1ed66
commit 5f82b8a1ad
1 changed files with 40 additions and 11 deletions
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51
lib/Analysis/LoopInfo.cpp
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@ -27,24 +27,24 @@ bool Loop::contains(const BasicBlock *BB) const {
bool Loop::isLoopExit(const BasicBlock *BB) const {
for (BasicBlock::succ_const_iterator SI = succ_begin(BB), SE = succ_end(BB);
SI != SE; ++SI) {
if (! contains(*SI))
if (!contains(*SI))
return true;
}
return false;
}
unsigned Loop::getNumBackEdges() const {
unsigned numBackEdges = 0;
BasicBlock *header = Blocks.front();
unsigned NumBackEdges = 0;
BasicBlock *H = getHeader();
for (std::vector<BasicBlock*>::const_iterator I = Blocks.begin(),
E = Blocks.end(); I != E; ++I) {
E = Blocks.end(); I != E; ++I)
for (BasicBlock::succ_iterator SI = succ_begin(*I), SE = succ_end(*I);
SI != SE; ++SI)
if (header == *SI)
++numBackEdges;
}
return numBackEdges;
if (*SI == H)
++NumBackEdges;
return NumBackEdges;
}
void Loop::print(std::ostream &OS) const {
@ -52,8 +52,16 @@ void Loop::print(std::ostream &OS) const {
for (unsigned i = 0; i < getBlocks().size(); ++i) {
if (i) OS << ",";
WriteAsOperand(OS, (const Value*)getBlocks()[i]);
WriteAsOperand(OS, getBlocks()[i], false);
}
if (!ExitBlocks.empty()) {
OS << "\tExitBlocks: ";
for (unsigned i = 0; i < getExitBlocks().size(); ++i) {
if (i) OS << ",";
WriteAsOperand(OS, getExitBlocks()[i], false);
}
}
OS << "\n";
for (unsigned i = 0, e = getSubLoops().size(); i != e; ++i)
@ -131,9 +139,9 @@ Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
BasicBlock *X = TodoStack.back();
TodoStack.pop_back();
if (!L->contains(X)) { // As of yet unprocessed??
if (!L->contains(X)) { // As of yet unprocessed??
L->Blocks.push_back(X);
// Add all of the predecessors of X to the end of the work stack...
TodoStack.insert(TodoStack.end(), pred_begin(X), pred_end(X));
}
@ -158,6 +166,14 @@ Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
BBMap.insert(BBMI, std::make_pair(*I, L)); // Must be at this level
}
// Now that we know all of the blocks that make up this loop, see if there are
// any branches to outside of the loop... building the ExitBlocks list.
for (std::vector<BasicBlock*>::iterator BI = L->Blocks.begin(),
BE = L->Blocks.end(); BI != BE; ++BI)
for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
if (!L->contains(*I)) // Not in current loop?
L->ExitBlocks.push_back(*I); // It must be an exit block...
return L;
}
@ -211,3 +227,16 @@ void Loop::addBasicBlockToLoop(BasicBlock *NewBB, LoopInfo &LI) {
L = L->getParentLoop();
}
}
/// changeExitBlock - This method is used to update loop information. One
/// instance of the specified Old basic block is removed from the exit list
/// and replaced with New.
///
void Loop::changeExitBlock(BasicBlock *Old, BasicBlock *New) {
assert(Old != New && "Cannot changeExitBlock to the same thing!");
assert(Old && New && "Cannot changeExitBlock to or from a null node!");
std::vector<BasicBlock*>::iterator I =
std::find(ExitBlocks.begin(), ExitBlocks.end(), Old);
assert(I != ExitBlocks.end() && "Old exit block not found!");
*I = New;
}