Port of all JIT changes for .NET Framework 4.6.1 changes

    http://blogs.msdn.com/b/dotnet/archive/2015/11/30/net-framework-4-6-1-is-now-available.aspx

.NET Framework list of changes in 4.6.1
    https://github.com/Microsoft/dotnet/blob/master/releases/net461/dotnet461-changes.md

Additional changes including
-    Working ARM64 JIT compiler
-    Additional JIT Optimizations
     o    Tail call recursion optimization
     o    Array length tracking optimization
     o    CSE for widening casts
     o    Smaller encoding for RIP relative and absolute addresses in addressing modes
     o    Tracked Local Variable increased to 512
     o    Improved handling of Intrinsics System.GetType()
     o    Improved handling of Math intrinsics
-    Work for the X86 Ryu-JIT compiler

[tfs-changeset: 1557101]

1 files changed, 27 insertions, 1 deletions

diff --git a/src/jit/regset.h b/src/jit/regset.h
index 985cee71d7..3b0ccae614 100644
--- a/src/jit/regset.h
+++ b/src/jit/regset.h
@@ -155,10 +155,36 @@ public: // TODO-Cleanup: Should be private, but GCInfo uses them
 #ifdef LEGACY_BACKEND
     regMaskTP           rsMaskUsed;            // currently 'used' registers mask
 #endif // LEGACY_BACKEND
-    regMaskTP           rsMaskVars;            // mask of registers currently allocated to variables
+
+    __declspec(property(get=GetMaskVars,put=SetMaskVars))
+    regMaskTP           rsMaskVars;             // mask of registers currently allocated to variables
+
+    regMaskTP GetMaskVars() const               // 'get' property function for rsMaskVars property
+    {
+        return _rsMaskVars;
+    }
+
+    void SetMaskVars(regMaskTP newMaskVars);    // 'put' property function for rsMaskVars property
+
+    void AddMaskVars(regMaskTP addMaskVars)     // union 'addMaskVars' with the rsMaskVars set
+    {
+        SetMaskVars(_rsMaskVars | addMaskVars);
+    }
+
+    void RemoveMaskVars(regMaskTP removeMaskVars)   // remove 'removeMaskVars' from the rsMaskVars set (like bitset DiffD)
+    {
+        SetMaskVars(_rsMaskVars & ~removeMaskVars);
+    }
+
+    void ClearMaskVars()                        // Like SetMaskVars(RBM_NONE), but without any debug output.
+    {
+        _rsMaskVars = RBM_NONE;
+    }
 
 private:
 
+    regMaskTP           _rsMaskVars;            // backing store for rsMaskVars property
+
 #ifdef LEGACY_BACKEND
     regMaskTP           rsMaskLock;            // currently 'locked' registers mask
     regMaskTP           rsMaskMult;            // currently 'multiply used' registers mask