Fix up file header


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8428 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 4203818..02a1dbd 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -1,7 +1,9 @@
 //===- IndVarSimplify.cpp - Induction Variable Elimination ----------------===//
 //
-// InductionVariableSimplify - Transform induction variables in a program
-//   to all use a single cannonical induction variable per loop.
+// Guarantees that all loops with identifiable, linear, induction variables will
+// be transformed to have a single, cannonical, induction variable.  After this
+// pass runs, it guarantees the the first PHI node of the header block in the
+// loop is the cannonical induction variable if there is one.
 //
 //===----------------------------------------------------------------------===//