[SelectionDAG] Make SelectCode return void

SelectCode has been returning nullptr since 182dac0 ("SDAG: Make
SelectCodeCommon return void", 2016-05-10). Make SelectCode also
return void instead, as all callers have been updated.

Patch by Sven van Haastregt.

Review: https://reviews.llvm.org/D30497
llvm-svn: 297377
diff --git a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
index b18187b..4b00676 100644
--- a/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
+++ b/llvm/utils/TableGen/DAGISelMatcherEmitter.cpp
@@ -955,7 +955,7 @@
   formatted_raw_ostream OS(O);
 
   OS << "// The main instruction selector code.\n";
-  OS << "SDNode *SelectCode(SDNode *N) {\n";
+  OS << "void SelectCode(SDNode *N) {\n";
 
   MatcherTableEmitter MatcherEmitter(CGP);
 
@@ -970,7 +970,6 @@
 
   OS << "  #undef TARGET_VAL\n";
   OS << "  SelectCodeCommon(N, MatcherTable,sizeof(MatcherTable));\n";
-  OS << "  return nullptr;\n";
   OS << "}\n";
 
   // Next up, emit the function for node and pattern predicates: