Add a comment to the commit r165187.
llvm-svn: 165238
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index 23d0bb5..af0ee34 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1261,10 +1261,12 @@
if (!Phi)
return true;
- // Do LFTR if the exit condition's IV is *not* a simple counter.
+ // Do LFTR if PHI node is defined in the loop, but is *not* a counter.
int Idx = Phi->getBasicBlockIndex(L->getLoopLatch());
if (Idx < 0)
return true;
+
+ // Do LFTR if the exit condition's IV is *not* a simple counter.
Value *IncV = Phi->getIncomingValue(Idx);
return Phi != getLoopPhiForCounter(IncV, L, DT);
}