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

2 files changed, 9 insertions, 19 deletions

diff --git a/include/llvm/IR/Use.h b/include/llvm/IR/Use.h
index 33a69c4686..4bc7ce5000 100644
--- a/include/llvm/IR/Use.h
+++ b/include/llvm/IR/Use.h
@@ -149,14 +149,14 @@ private:
 // casting operators.
 template<> struct simplify_type<Use> {
   typedef Value* SimpleType;
-  static SimpleType getSimplifiedValue(const Use &Val) {
-    return static_cast<SimpleType>(Val.get());
+  static SimpleType getSimplifiedValue(Use &Val) {
+    return Val.get();
   }
 };
 template<> struct simplify_type<const Use> {
-  typedef Value* SimpleType;
+  typedef /*const*/ Value* SimpleType;
   static SimpleType getSimplifiedValue(const Use &Val) {
-    return static_cast<SimpleType>(Val.get());
+    return Val.get();
   }
 };
 
diff --git a/include/llvm/IR/User.h b/include/llvm/IR/User.h
index a4d0a5d7df..505bdeb178 100644
--- a/include/llvm/IR/User.h
+++ b/include/llvm/IR/User.h
@@ -183,27 +183,17 @@ public:
 
 template<> struct simplify_type<User::op_iterator> {
   typedef Value* SimpleType;
-
-  static SimpleType getSimplifiedValue(const User::op_iterator &Val) {
-    return static_cast<SimpleType>(Val->get());
+  static SimpleType getSimplifiedValue(User::op_iterator &Val) {
+    return Val->get();
   }
 };
-
-template<> struct simplify_type<const User::op_iterator>
-  : public simplify_type<User::op_iterator> {};
-
 template<> struct simplify_type<User::const_op_iterator> {
-  typedef Value* SimpleType;
-
-  static SimpleType getSimplifiedValue(const User::const_op_iterator &Val) {
-    return static_cast<SimpleType>(Val->get());
+  typedef /*const*/ Value* SimpleType;
+  static SimpleType getSimplifiedValue(User::const_op_iterator &Val) {
+    return Val->get();
   }
 };
 
-template<> struct simplify_type<const User::const_op_iterator>
-  : public simplify_type<User::const_op_iterator> {};
-
-
 // value_use_iterator::getOperandNo - Requires the definition of the User class.
 template<typename UserTy>
 unsigned value_use_iterator<UserTy>::getOperandNo() const {