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Change the ExitBlocks list from being explicitly contained in the Loop

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structure to being dynamically computed on demand.  This makes updating
loop information MUCH easier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13045 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2004-04-18 22:14:10 +00:00
parent 7c8781e71f
commit f1ab4b4eac
7 changed files with 45 additions and 184 deletions
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55
lib/Analysis/LoopInfo.cpp
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@ -63,14 +63,6 @@ void Loop::print(std::ostream &OS, unsigned Depth) const {
if (i) OS << ",";
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 (iterator I = begin(), E = end(); I != E; ++I)
@ -248,14 +240,6 @@ Loop *LoopInfo::ConsiderForLoop(BasicBlock *BB, const DominatorSet &DS) {
}
}
// 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;
}
@ -344,6 +328,18 @@ void LoopInfo::removeBlock(BasicBlock *BB) {
// APIs for simple analysis of the loop.
//
/// getExitBlocks - Return all of the successor blocks of this loop. These
/// are the blocks _outside of the current loop_ which are branched to.
///
void Loop::getExitBlocks(std::vector<BasicBlock*> &Blocks) const {
for (std::vector<BasicBlock*>::const_iterator BI = Blocks.begin(),
BE = Blocks.end(); BI != BE; ++BI)
for (succ_iterator I = succ_begin(*BI), E = succ_end(*BI); I != E; ++I)
if (!contains(*I)) // Not in current loop?
Blocks.push_back(*I); // It must be an exit block...
}
/// 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
@ -481,22 +477,6 @@ void Loop::addBasicBlockToLoop(BasicBlock *NewBB, LoopInfo &LI) {
}
}
/// changeExitBlock - This method is used to update loop information. All
/// instances of the specified Old basic block are 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!");
assert(hasExitBlock(Old) && "Old exit block not found!");
std::vector<BasicBlock*>::iterator
I = std::find(ExitBlocks.begin(), ExitBlocks.end(), Old);
while (I != ExitBlocks.end()) {
*I = New;
I = std::find(I+1, ExitBlocks.end(), Old);
}
}
/// replaceChildLoopWith - This is used when splitting loops up. It replaces
/// the OldChild entry in our children list with NewChild, and updates the
/// parent pointers of the two loops as appropriate.
@ -550,15 +530,4 @@ Loop *Loop::removeChildLoop(iterator I) {
/// does not update the mapping in the LoopInfo class.
void Loop::removeBlockFromLoop(BasicBlock *BB) {
RemoveFromVector(Blocks, BB);
// If this block branched out of this loop, remove any exit blocks entries due
// to it.
for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
if (!contains(*SI) && *SI != BB)
RemoveFromVector(ExitBlocks, *SI);
// If any blocks in this loop branch to BB, add it to the exit blocks set.
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
if (contains(*PI))
ExitBlocks.push_back(BB);
}