- LoopInfo now calculates and tracks loop exit blocks
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5650 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 497732b..a361e62 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -27,24 +27,24 @@
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 @@
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 @@
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 @@
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 @@
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;
+}