Make getNumBackEdges more efficient
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9063 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 8c42562..e92f10d 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -33,17 +33,16 @@
return false;
}
+/// getNumBackEdges - Calculate the number of back edges to the loop header.
+///
unsigned Loop::getNumBackEdges() const {
unsigned NumBackEdges = 0;
BasicBlock *H = getHeader();
- for (std::vector<BasicBlock*>::const_iterator I = Blocks.begin(),
- E = Blocks.end(); I != E; ++I)
- for (succ_iterator SI = succ_begin(*I), SE = succ_end(*I);
- SI != SE; ++SI)
- if (*SI == H)
- ++NumBackEdges;
-
+ for (pred_iterator I = pred_begin(H), E = pred_end(H); I != E; ++I)
+ if (contains(*I))
+ ++NumBackEdges;
+
return NumBackEdges;
}