Fix typo in comment.

llvm-svn: 133990
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 506e5e8..b1dd733 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -642,7 +642,7 @@
   bool Changed = false;
 
   // This implementation doesn't currently consider undef operands
-  // specially. Theroetically, two phis which are identical except for
+  // specially. Theoretically, two phis which are identical except for
   // one having an undef where the other doesn't could be collapsed.
 
   // Map from PHI hash values to PHI nodes. If multiple PHIs have