Fix a ton of comment typos found by codespell.  Patch by
Luis Felipe Strano Moraes!

llvm-svn: 129558
diff --git a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
index f17023e..67c209e 100644
--- a/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
+++ b/llvm/lib/CodeGen/ScheduleDAGInstrs.cpp
@@ -371,7 +371,7 @@
                 // will be overlapped by work done outside the current
                 // scheduling region.
                 Latency -= std::min(Latency, Count);
-                // Add the artifical edge.
+                // Add the artificial edge.
                 ExitSU.addPred(SDep(SU, SDep::Order, Latency,
                                     /*Reg=*/0, /*isNormalMemory=*/false,
                                     /*isMustAlias=*/false,