Added helper functions in LoopInfo: isLoopExit and numBackEdges.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4112 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 6c531ac..dd70295 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -44,7 +44,10 @@
/// isLoopExit - True if terminator in the block can branch to another block
/// that is outside of the current loop.
- bool isLoopExit(BasicBlock *BB) const;
+ bool isLoopExit(const BasicBlock *BB) const;
+
+ /// Find number of back edges
+ unsigned getNumBackEdges() const;
/// 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
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 1f8e34c..002e553 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -24,6 +24,30 @@
return find(Blocks.begin(), Blocks.end(), BB) != Blocks.end();
}
+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))
+ return true;
+ }
+ return false;
+}
+
+unsigned Loop::getNumBackEdges() const {
+ unsigned numBackEdges = 0;
+ BasicBlock *header = Blocks.front();
+
+ for (std::vector<BasicBlock*>::const_iterator i = Blocks.begin(), e = Blocks.end();
+ i != e; ++i) {
+ for (BasicBlock::succ_iterator Successor = succ_begin(*i), SEnd = succ_end(*i);
+ Successor != SEnd; ++Successor) {
+ if (header == *Successor)
+ ++numBackEdges;
+ }
+ }
+ return numBackEdges;
+}
+
void Loop::print(std::ostream &OS) const {
OS << std::string(getLoopDepth()*2, ' ') << "Loop Containing: ";