Move getCommonSubClass() into TRI.

It will soon need the context.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140896 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index b0239e1..d547c96 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -113,7 +113,8 @@
             if (!UseRC)
               UseRC = RC;
             else if (RC) {
-              const TargetRegisterClass *ComRC = getCommonSubClass(UseRC, RC);
+              const TargetRegisterClass *ComRC =
+                TRI->getCommonSubClass(UseRC, RC);
               // If multiple uses expect disjoint register classes, we emit
               // copies in AddRegisterOperand.
               if (ComRC)