[stackprotector] Refactor out the end of isInTailCallPosition into the function returnTypeIsEligibleForTailCall.

This allows me to use returnTypeIsEligibleForTailCall in the stack protector pass.

rdar://13935163

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188765 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/Analysis.h

@@ -26,6 +26,7 @@ namespace llvm {
 
 class GlobalVariable;
 class TargetLowering;
+class TargetLoweringBase;
 class SDNode;
 class SDValue;
 class SelectionDAG;
@@ -88,6 +89,14 @@ ISD::CondCode getICmpCondCode(ICmpInst::Predicate Pred);
 /// This function only tests target-independent requirements.
 bool isInTailCallPosition(ImmutableCallSite CS, const TargetLowering &TLI);
 
+/// Test if given that the input instruction is in the tail call position if the
+/// return type or any attributes of the function will inhibit tail call
+/// optimization.
+bool returnTypeIsEligibleForTailCall(const Function *F,
+                                     const Instruction *I,
+                                     const ReturnInst *Ret,
+                                     const TargetLoweringBase &TLI);
+
 } // End llvm namespace
 
 #endif