add support for the new isel matcher to generate 
(isprofitable|islegal)tofold checks.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96331 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/DAGISelEmitter.cpp b/utils/TableGen/DAGISelEmitter.cpp
index d2e260e..243700f 100644
--- a/utils/TableGen/DAGISelEmitter.cpp
+++ b/utils/TableGen/DAGISelEmitter.cpp
@@ -586,6 +586,8 @@
         //      /        [YY]
         //      |         ^
         //     [XX]-------|
+        
+        // We know we need the check if N's parent is not the root.
         bool NeedCheck = P != Pattern;
         if (!NeedCheck) {
           const SDNodeInfo &PInfo = CGP.getSDNodeInfo(P->getOperator());