Cleanup the simplify_type implementation.

As far as simplify_type is concerned, there are 3 kinds of smart pointers:

* const correct: A 'const MyPtr<int> &' produces a 'const int*'. A
'MyPtr<int> &' produces a 'int *'.
* always const: Even a 'MyPtr<int> &' produces a 'const int*'.
* no const: Even a 'const MyPtr<int> &' produces a 'int*'.

This patch then does the following:

* Removes the unused specializations. Since they are unused, it is hard
to know which kind should be implemented.
* Make sure we don't drop const.
* Fix the default forwarding so that const correct pointer only need
one specialization.
* Simplifies the existing specializations.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178147 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 12 deletions

diff --git a/include/llvm/CodeGen/SelectionDAGNodes.h b/include/llvm/CodeGen/SelectionDAGNodes.h
index 05f3b14..fef567f 100644
--- a/include/llvm/CodeGen/SelectionDAGNodes.h
+++ b/include/llvm/CodeGen/SelectionDAGNodes.h
@@ -196,14 +196,14 @@ template <> struct isPodLike<SDValue> { static const bool value = true; };
 /// SDValues as if they were SDNode*'s.
 template<> struct simplify_type<SDValue> {
   typedef SDNode* SimpleType;
-  static SimpleType getSimplifiedValue(const SDValue &Val) {
-    return static_cast<SimpleType>(Val.getNode());
+  static SimpleType getSimplifiedValue(SDValue &Val) {
+    return Val.getNode();
   }
 };
 template<> struct simplify_type<const SDValue> {
-  typedef SDNode* SimpleType;
+  typedef /*const*/ SDNode* SimpleType;
   static SimpleType getSimplifiedValue(const SDValue &Val) {
-    return static_cast<SimpleType>(Val.getNode());
+    return Val.getNode();
   }
 };
 
@@ -295,14 +295,8 @@ private:
 /// SDValues as if they were SDNode*'s.
 template<> struct simplify_type<SDUse> {
   typedef SDNode* SimpleType;
-  static SimpleType getSimplifiedValue(const SDUse &Val) {
-    return static_cast<SimpleType>(Val.getNode());
-  }
-};
-template<> struct simplify_type<const SDUse> {
-  typedef SDNode* SimpleType;
-  static SimpleType getSimplifiedValue(const SDUse &Val) {
-    return static_cast<SimpleType>(Val.getNode());
+  static SimpleType getSimplifiedValue(SDUse &Val) {
+    return Val.getNode();
   }
 };