Don't recalculate intrinsic id in Value::setName()

llvm/include/llvm/IR/Function.h

public:
 
   /// Returns true if the function is one of the "Constrained Floating-Point
   /// Intrinsics". Returns false if not, and returns false when
   /// getIntrinsicID() returns Intrinsic::not_intrinsic.
   bool isConstrainedFPIntrinsic() const;
 
   static Intrinsic::ID lookupIntrinsicID(StringRef Name);
 
-  /// Recalculate the ID for this function if it is an Intrinsic defined
-  /// in llvm/Intrinsics.h.  Sets the intrinsic ID to Intrinsic::not_intrinsic
-  /// if the name of this function does not match an intrinsic in that header.
-  /// Note, this method does not need to be called directly, as it is called
-  /// from Value::setName() whenever the name of this function changes.
-  void recalculateIntrinsicID();
-
   /// getCallingConv()/setCallingConv(CC) - These method get and set the
   /// calling convention of this function.  The enum values for the known
   /// calling conventions are defined in CallingConv.h.
   CallingConv::ID getCallingConv() const {
     return static_cast<CallingConv::ID>((getSubclassDataFromValue() >> 4) &
                                         CallingConv::MaxID);
   }
   void setCallingConv(CallingConv::ID CC) {

llvm/lib/IR/Function.cpp

Function::Function(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace,
 
   // If the function has arguments, mark them as lazily built.
   if (Ty->getNumParams())
     setValueSubclassData(1);   // Set the "has lazy arguments" bit.
 
   if (ParentModule)
     ParentModule->getFunctionList().push_back(this);
 
-  HasLLVMReservedName = getName().startswith("llvm.");
+  if (getName().startswith("llvm.")) {
+    HasLLVMReservedName = true;
+    IntID = lookupIntrinsicID(getName());
+  } else {
+    HasLLVMReservedName = false;
+    IntID = Intrinsic::not_intrinsic;
+  }
   // Ensure intrinsics have the right parameter attributes.
   // Note, the IntID field will have been set in Value::setName if this function
   // name is a valid intrinsic ID.
   if (IntID)
     setAttributes(Intrinsic::getAttributes(getContext(), IntID));
 }
 
 Function::~Function() {
Intrinsic::ID Function::lookupIntrinsicID(StringRef Name) {
   // overloaded, require either exact or prefix match.
   const auto MatchSize = strlen(NameTable[Idx]);
   assert(Name.size() >= MatchSize && "Expected either exact or prefix match");
   bool IsExactMatch = Name.size() == MatchSize;
   return IsExactMatch || Intrinsic::isOverloaded(ID) ? ID
                                                      : Intrinsic::not_intrinsic;
 }
 
-void Function::recalculateIntrinsicID() {
-  StringRef Name = getName();
-  if (!Name.startswith("llvm.")) {
-    HasLLVMReservedName = false;
-    IntID = Intrinsic::not_intrinsic;
-    return;
-  }
-  HasLLVMReservedName = true;
-  IntID = lookupIntrinsicID(Name);
-}
-
 /// Returns a stable mangling for the type specified for use in the name
 /// mangling scheme used by 'any' types in intrinsic signatures.  The mangling
 /// of named types is simply their name.  Manglings for unnamed types consist
 /// of a prefix ('p' for pointers, 'a' for arrays, 'f_' for functions)
 /// combined with the mangling of their component types.  A vararg function
 /// type will have a suffix of 'vararg'.  Since function types can contain
 /// other function types, we close a function type mangling with suffix 'f'
 /// which can't be confused with it's prefix.  This ensures we don't have

llvm/lib/IR/Value.cpp

void Value::setNameImpl(const Twine &NewName) {
   }
 
   // Name is changing to something new.
   setValueName(ST->createValueName(NameRef, this));
 }
 
 void Value::setName(const Twine &NewName) {
   setNameImpl(NewName);
-  if (Function *F = dyn_cast<Function>(this))
-    F->recalculateIntrinsicID();
 }
 
 void Value::takeName(Value *V) {
   assert(V != this && "Illegal call to this->takeName(this)!");
   ValueSymbolTable *ST = nullptr;
   // If this value has a name, drop it.
   if (hasName()) {
     // Get the symtab this is in.