[IRBuilder] Move CreateNeg() to fold API

Remove the CreateNeg() method from IRBuilderFolder and base it on
CreateSub(0, V) instead, which will call FoldNoWrapBinaryOp().

May not be NFC if InstSimplifyFolder is used.

llvm/include/llvm/Analysis/InstSimplifyFolder.h

@@ -111,10 +111,6 @@ public:
   // Unary Operators
   //===--------------------------------------------------------------------===//
 
-  Value *CreateNeg(Constant *C, bool HasNUW = false,
-                   bool HasNSW = false) const override {
-    return ConstFolder.CreateNeg(C, HasNUW, HasNSW);
-  }
   Value *CreateFNeg(Constant *C) const override {
     return ConstFolder.CreateFNeg(C);
   }

llvm/include/llvm/Analysis/TargetFolder.h

@@ -168,10 +168,6 @@ public:
   // Unary Operators
   //===--------------------------------------------------------------------===//
 
-  Constant *CreateNeg(Constant *C,
-                      bool HasNUW = false, bool HasNSW = false) const override {
-    return Fold(ConstantExpr::getNeg(C, HasNUW, HasNSW));
-  }
   Constant *CreateFNeg(Constant *C) const override {
     return Fold(ConstantExpr::getFNeg(C));
   }

llvm/include/llvm/IR/ConstantFolder.h

@@ -158,11 +158,6 @@ public:
   // Unary Operators
   //===--------------------------------------------------------------------===//
 
-  Constant *CreateNeg(Constant *C,
-                      bool HasNUW = false, bool HasNSW = false) const override {
-    return ConstantExpr::getNeg(C, HasNUW, HasNSW);
-  }
-
   Constant *CreateFNeg(Constant *C) const override {
     return ConstantExpr::getFNeg(C);
   }

llvm/include/llvm/IR/IRBuilder.h

@@ -1572,14 +1572,10 @@ public:
       Optional<RoundingMode> Rounding = None,
       Optional<fp::ExceptionBehavior> Except = None);
 
-  Value *CreateNeg(Value *V, const Twine &Name = "",
-                   bool HasNUW = false, bool HasNSW = false) {
-    if (auto *VC = dyn_cast<Constant>(V))
-      return Insert(Folder.CreateNeg(VC, HasNUW, HasNSW), Name);
-    BinaryOperator *BO = Insert(BinaryOperator::CreateNeg(V), Name);
-    if (HasNUW) BO->setHasNoUnsignedWrap();
-    if (HasNSW) BO->setHasNoSignedWrap();
-    return BO;
+  Value *CreateNeg(Value *V, const Twine &Name = "", bool HasNUW = false,
+                   bool HasNSW = false) {
+    return CreateSub(Constant::getNullValue(V->getType()), V, Name, HasNUW,
+                     HasNSW);
   }
 
   Value *CreateNSWNeg(Value *V, const Twine &Name = "") {

llvm/include/llvm/IR/IRBuilderFolder.h

@@ -71,8 +71,6 @@ public:
   // Unary Operators
   //===--------------------------------------------------------------------===//
 
-  virtual Value *CreateNeg(Constant *C,
-                           bool HasNUW = false, bool HasNSW = false) const = 0;
   virtual Value *CreateFNeg(Constant *C) const = 0;
   virtual Value *CreateUnOp(Instruction::UnaryOps Opc, Constant *C) const = 0;
 

llvm/include/llvm/IR/NoFolder.h

@@ -106,15 +106,6 @@ public:
   // Unary Operators
   //===--------------------------------------------------------------------===//
 
-  Instruction *CreateNeg(Constant *C,
-                         bool HasNUW = false,
-                         bool HasNSW = false) const override {
-    BinaryOperator *BO = BinaryOperator::CreateNeg(C);
-    if (HasNUW) BO->setHasNoUnsignedWrap();
-    if (HasNSW) BO->setHasNoSignedWrap();
-    return BO;
-  }
-
   Instruction *CreateFNeg(Constant *C) const override {
     return UnaryOperator::CreateFNeg(C);
   }