x86 users can now return arbitrary sized structs.  Structs too large to fit in return registers will be returned through a hidden sret parameter introduced during SelectionDAG construction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86876 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
index bde2f3b..10f256c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
@@ -90,6 +90,14 @@
   MachineFunction *MF;
   MachineRegisterInfo *RegInfo;
 
+  /// CanLowerReturn - true iff the function's return value can be lowered to
+  /// registers.
+  bool CanLowerReturn;
+
+  /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg
+  /// allocated to hold a pointer to the hidden sret parameter.
+  unsigned DemoteRegister;
+
   explicit FunctionLoweringInfo(TargetLowering &TLI);
 
   /// set - Initialize this FunctionLoweringInfo with the given Function