[GlobalMerge] Fix a typo

now => know

llvm-svn: 330965
diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp
index e4fa544..ea33ea4 100644
--- a/llvm/lib/CodeGen/GlobalMerge.cpp
+++ b/llvm/lib/CodeGen/GlobalMerge.cpp
@@ -242,7 +242,7 @@
   // code (currently, a Function) to the set of globals seen so far that are
   // used together in that unit (GlobalUsesByFunction).
   //
-  // When we look at the Nth global, we now that any new set is either:
+  // When we look at the Nth global, we know that any new set is either:
   // - the singleton set {N}, containing this global only, or
   // - the union of {N} and a previously-discovered set, containing some
   //   combination of the previous N-1 globals.