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Move getUniqueExitBlocks from LoopBase to Loop, since they depend on 

LoopSimplify form, which is currently only available on Loops (and
not MachineLoops). Also, move the code out of the header file.

llvm-svn: 80923
This commit is contained in:
Dan Gohman 2009-09-03 16:10:48 +00:00
parent 0054b460ff
commit 3a0ce3e639
2 changed files with 78 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
llvm/include/llvm/Analysis/LoopInfo.h
View File

@ -230,74 +230,6 @@ public:
ExitEdges.push_back(std::make_pair(*BI, *I));
}
/// getUniqueExitBlocks - Return all unique successor blocks of this loop.
/// These are the blocks _outside of the current loop_ which are branched to.
/// This assumes that loop is in canonical form.
///
void getUniqueExitBlocks(SmallVectorImpl<BlockT*> &ExitBlocks) const {
// Sort the blocks vector so that we can use binary search to do quick
// lookups.
SmallVector<BlockT*, 128> LoopBBs(block_begin(), block_end());
std::sort(LoopBBs.begin(), LoopBBs.end());
std::vector<BlockT*> switchExitBlocks;
for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI) {
BlockT *current = *BI;
switchExitBlocks.clear();
typedef GraphTraits<BlockT*> BlockTraits;
typedef GraphTraits<Inverse<BlockT*> > InvBlockTraits;
for (typename BlockTraits::ChildIteratorType I =
BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
I != E; ++I) {
if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
// If block is inside the loop then it is not a exit block.
continue;
typename InvBlockTraits::ChildIteratorType PI =
InvBlockTraits::child_begin(*I);
BlockT *firstPred = *PI;
// If current basic block is this exit block's first predecessor
// then only insert exit block in to the output ExitBlocks vector.
// This ensures that same exit block is not inserted twice into
// ExitBlocks vector.
if (current != firstPred)
continue;
// If a terminator has more then two successors, for example SwitchInst,
// then it is possible that there are multiple edges from current block
// to one exit block.
if (std::distance(BlockTraits::child_begin(current),
BlockTraits::child_end(current)) <= 2) {
ExitBlocks.push_back(*I);
continue;
}
// In case of multiple edges from current block to exit block, collect
// only one edge in ExitBlocks. Use switchExitBlocks to keep track of
// duplicate edges.
if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I)
== switchExitBlocks.end()) {
switchExitBlocks.push_back(*I);
ExitBlocks.push_back(*I);
}
}
}
}
/// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one
/// block, return that block. Otherwise return null.
BlockT *getUniqueExitBlock() const {
SmallVector<BlockT*, 8> UniqueExitBlocks;
getUniqueExitBlocks(UniqueExitBlocks);
if (UniqueExitBlocks.size() == 1)
return UniqueExitBlocks[0];
return 0;
}
/// getLoopPreheader - If there is a preheader for this loop, return it. A
/// loop has a preheader if there is only one edge to the header of the loop
/// from outside of the loop. If this is the case, the block branching to the
@ -569,6 +501,16 @@ public:
/// normal form.
bool isLoopSimplifyForm() const;
/// getUniqueExitBlocks - Return all unique successor blocks of this loop.
/// These are the blocks _outside of the current loop_ which are branched to.
/// This assumes that loop is in canonical form.
///
void getUniqueExitBlocks(SmallVectorImpl<BasicBlock *> &ExitBlocks) const;
/// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one
/// block, return that block. Otherwise return null.
BasicBlock *getUniqueExitBlock() const;
private:
friend class LoopInfoBase<BasicBlock, Loop>;
explicit Loop(BasicBlock *BB) : LoopBase<BasicBlock, Loop>(BB) {}

68
llvm/lib/Analysis/LoopInfo.cpp
View File

@ -294,6 +294,74 @@ bool Loop::isLoopSimplifyForm() const {
return true;
}
/// getUniqueExitBlocks - Return all unique successor blocks of this loop.
/// These are the blocks _outside of the current loop_ which are branched to.
/// This assumes that loop is in canonical form.
///
void
Loop::getUniqueExitBlocks(SmallVectorImpl<BasicBlock *> &ExitBlocks) const {
// Sort the blocks vector so that we can use binary search to do quick
// lookups.
SmallVector<BasicBlock *, 128> LoopBBs(block_begin(), block_end());
std::sort(LoopBBs.begin(), LoopBBs.end());
std::vector<BasicBlock *> switchExitBlocks;
for (block_iterator BI = block_begin(), BE = block_end(); BI != BE; ++BI) {
BasicBlock *current = *BI;
switchExitBlocks.clear();
typedef GraphTraits<BasicBlock *> BlockTraits;
typedef GraphTraits<Inverse<BasicBlock *> > InvBlockTraits;
for (BlockTraits::ChildIteratorType I =
BlockTraits::child_begin(*BI), E = BlockTraits::child_end(*BI);
I != E; ++I) {
// If block is inside the loop then it is not a exit block.
if (std::binary_search(LoopBBs.begin(), LoopBBs.end(), *I))
continue;
InvBlockTraits::ChildIteratorType PI = InvBlockTraits::child_begin(*I);
BasicBlock *firstPred = *PI;
// If current basic block is this exit block's first predecessor
// then only insert exit block in to the output ExitBlocks vector.
// This ensures that same exit block is not inserted twice into
// ExitBlocks vector.
if (current != firstPred)
continue;
// If a terminator has more then two successors, for example SwitchInst,
// then it is possible that there are multiple edges from current block
// to one exit block.
if (std::distance(BlockTraits::child_begin(current),
BlockTraits::child_end(current)) <= 2) {
ExitBlocks.push_back(*I);
continue;
}
// In case of multiple edges from current block to exit block, collect
// only one edge in ExitBlocks. Use switchExitBlocks to keep track of
// duplicate edges.
if (std::find(switchExitBlocks.begin(), switchExitBlocks.end(), *I)
== switchExitBlocks.end()) {
switchExitBlocks.push_back(*I);
ExitBlocks.push_back(*I);
}
}
}
}
/// getUniqueExitBlock - If getUniqueExitBlocks would return exactly one
/// block, return that block. Otherwise return null.
BasicBlock *Loop::getUniqueExitBlock() const {
SmallVector<BasicBlock *, 8> UniqueExitBlocks;
getUniqueExitBlocks(UniqueExitBlocks);
if (UniqueExitBlocks.size() == 1)
return UniqueExitBlocks[0];
return 0;
}
//===----------------------------------------------------------------------===//
// LoopInfo implementation
//