[clang][Interp] Implement bitwise Not operations

[shafik]

clang/test/AST/Interp/literals.cpp

76

Some more tests covering ~INT_MIN == INT_MAX and vice versa and unscoped enum case as well e.g.

enum E {};
E e = static_cast<E>(0);
static_assert(~e == -1, "");

[shafik]

Otherwise LGTM

[aaron.ballman]

LGTM aside from a question about naming.

clang/lib/AST/Interp/Integral.h

215–218

Can we name this one complement instead of not -- when I hear not I think ! and not ~.

clang/lib/AST/Interp/Interp.h

187

189

Same naming request here.

clang/lib/AST/Interp/Opcodes.td

415

Here too.

[aaron.ballman]

LGTM!

clang/lib/AST/Interp/ByteCodeExprGen.cpp

return dereference(
         [](PrimType) {
           llvm_unreachable("Dereferencing requires a pointer");
           return false;
         },
         [this, E](PrimType T) {
           return DiscardResult ? this->emitPop(T, E) : true;
         });
   case UO_Not:    // ~x
+    if (!this->Visit(SubExpr))
+      return false;
+    if (Optional<PrimType> T = classify(E->getType()))
+      return this->emitComp(*T, E);
+    return false;
   case UO_Real:   // __real x
   case UO_Imag:   // __imag x
   case UO_Extension:
   case UO_Coawait:
     assert(false && "Unhandled opcode");
   }
 
   return false;

clang/lib/AST/Interp/Integral.h

static bool mul(Integral A, Integral B, unsigned OpBits, Integral *R) {
     return CheckMulUB(A.V, B.V, R->V);
   }
 
   static bool neg(Integral A, Integral *R) {
     *R = -A;
     return false;
   }
 
+  static bool comp(Integral A, Integral *R) {
+    *R = Integral(~A.V);
+    return false;
+  }
+
 private:
   template <typename T> static bool CheckAddUB(T A, T B, T &R) {
     if constexpr (std::is_signed_v<T>) {
       return llvm::AddOverflow<T>(A, B, R);
     } else {
       R = A + B;
       return false;
     }

clang/lib/AST/Interp/Interp.h

bool Neg(InterpState &S, CodePtr OpPC) {
   const T &Val = S.Stk.pop<T>();
   T Result;
   T::neg(Val, &Result);
 
   S.Stk.push<T>(Result);
   return true;
 }
 
+/// 1) Pops the value from the stack.
+/// 2) Pushes the bitwise complemented value on the stack (~V).
+template <PrimType Name, class T = typename PrimConv<Name>::T>
+bool Comp(InterpState &S, CodePtr OpPC) {
+  const T &Val = S.Stk.pop<T>();
+  T Result;
+  if (!T::comp(Val, &Result)) {
+    S.Stk.push<T>(Result);
+    return true;
+  }
+
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // EQ, NE, GT, GE, LT, LE
 //===----------------------------------------------------------------------===//
 
 using CompareFn = llvm::function_ref<bool(ComparisonCategoryResult)>;
 
 template <typename T>
 bool CmpHelper(InterpState &S, CodePtr OpPC, CompareFn Fn) {

clang/lib/AST/Interp/Opcodes.td

 }
 
 // [Real] -> [Real]
 def Neg: Opcode {
   let Types = [AluTypeClass];
   let HasGroup = 1;
 }
 
+// [Real] -> [Real]
+def Comp: Opcode {
+  let Types = [NumberTypeClass];
+  let HasGroup = 1;
+}
+
 //===----------------------------------------------------------------------===//
 // Cast.
 //===----------------------------------------------------------------------===//
 // TODO: Expand this to handle casts between more types.
 
 def FromCastTypeClass : TypeClass {
   let Types = [Uint8, Sint8, Uint16, Sint16, Uint32, Sint32, Uint64, Sint64, Bool];
 }

clang/test/AST/Interp/literals.cpp

 // RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++11 -verify %s
 // RUN: %clang_cc1 -fexperimental-new-constant-interpreter -std=c++20 -verify %s
 // RUN: %clang_cc1 -std=c++11 -verify=ref %s
 // RUN: %clang_cc1 -std=c++20 -verify=ref %s
 
+#define INT_MIN (~__INT_MAX__)
+#define INT_MAX __INT_MAX__
+
+
 static_assert(true, "");
 static_assert(false, ""); // expected-error{{failed}} ref-error{{failed}}
 static_assert(nullptr == nullptr, "");
 static_assert(1 == 1, "");
 static_assert(1 == 3, ""); // expected-error{{failed}} ref-error{{failed}}
 
 constexpr int number = 10;
 static_assert(number == 10, "");

 static_assert(!!true == !false, "");
 static_assert(true == 1, "");
 static_assert(false == 0, "");
 static_assert(!5 == false, "");
 static_assert(!0, "");
 static_assert(-true, "");
 static_assert(-false, ""); //expected-error{{failed}} ref-error{{failed}}
 
+static_assert(~0 == -1, "");
+static_assert(~1 == -2, "");
+static_assert(~-1 == 0, "");
+static_assert(~255 == -256, "");
+static_assert(~INT_MIN == INT_MAX, "");
+static_assert(~INT_MAX == INT_MIN, "");
+
+enum E {};
+constexpr E e = static_cast<E>(0);
+static_assert(~e == -1, "");
+
+
 constexpr int m = 10;
 constexpr const int *p = &m;
 static_assert(p != nullptr, "");
 static_assert(*p == 10, "");
 
 constexpr const int* getIntPointer() {
   return &m;
 }