Sink a function that refers to the SelectionDAG into that library in the

one file where it is called as a static function. Nuke the declaration
and the definition in lib/CodeGen, along with the include of
SelectionDAG.h from this file.

There is no dependency edge from lib/CodeGen to
lib/CodeGen/SelectionDAG, so it isn't valid for a routine in lib/CodeGen
to reference the DAG. There is a dependency from
lib/CodeGen/SelectionDAG on lib/CodeGen. This breaks one violation of
this layering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171842 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/Analysis.cpp

@@ -14,7 +14,6 @@
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
@@ -348,23 +347,3 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attribute CalleeRetAttr,
   
   return true;
 }
-
-bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node,
-                                SDValue &Chain, const TargetLowering &TLI) {
-  const Function *F = DAG.getMachineFunction().getFunction();
-
-  // Conservatively require the attributes of the call to match those of
-  // the return. Ignore noalias because it doesn't affect the call sequence.
-  Attribute CallerRetAttr = F->getAttributes().getRetAttributes();
-  if (AttrBuilder(CallerRetAttr)
-      .removeAttribute(Attribute::NoAlias).hasAttributes())
-    return false;
-
-  // It's not safe to eliminate the sign / zero extension of the return value.
-  if (CallerRetAttr.hasAttribute(Attribute::ZExt) ||
-      CallerRetAttr.hasAttribute(Attribute::SExt))
-    return false;
-
-  // Check if the only use is a function return node.
-  return TLI.isUsedByReturnOnly(Node, Chain);
-}