[CodeGen] Add space-optimized EmitMergeInputChains1_2 to the DAG isel matching tables. Shaves about 5100 bytes from the X86 matcher table. NFC

llvm-svn: 262815
diff --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index 26f53dc..4f944be 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -500,8 +500,8 @@
     const EmitMergeInputChainsMatcher *MN =
       cast<EmitMergeInputChainsMatcher>(N);
 
-    // Handle the specialized forms OPC_EmitMergeInputChains1_0 and 1_1.
-    if (MN->getNumNodes() == 1 && MN->getNode(0) < 2) {
+    // Handle the specialized forms OPC_EmitMergeInputChains1_0, 1_1, and 1_2.
+    if (MN->getNumNodes() == 1 && MN->getNode(0) < 3) {
       OS << "OPC_EmitMergeInputChains1_" << MN->getNode(0) << ",\n";
       return 1;
     }