Implement a bunch more TargetSelectionDAGInfo infrastructure.

Move EmitTargetCodeForMemcpy, EmitTargetCodeForMemset, and
EmitTargetCodeForMemmove out of TargetLowering and into
SelectionDAGInfo to exercise this.

llvm-svn: 103481
diff --git a/llvm/lib/Target/Alpha/AlphaSelectionDAGInfo.h b/llvm/lib/Target/Alpha/AlphaSelectionDAGInfo.h
index 70889ae..3405cc0 100644
--- a/llvm/lib/Target/Alpha/AlphaSelectionDAGInfo.h
+++ b/llvm/lib/Target/Alpha/AlphaSelectionDAGInfo.h
@@ -18,9 +18,11 @@
 
 namespace llvm {
 
+class AlphaTargetMachine;
+
 class AlphaSelectionDAGInfo : public TargetSelectionDAGInfo {
 public:
-  AlphaSelectionDAGInfo();
+  explicit AlphaSelectionDAGInfo(const AlphaTargetMachine &TM);
   ~AlphaSelectionDAGInfo();
 };