[clang][Interp] Implement _Complex Not unary operators

This only happens in C as far as I can tell. The complex varialbe
will have undergone a conversion to bool in C++ before reaching
the unary operator.

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -3182,6 +3182,17 @@ bool ByteCodeExprGen<Emitter>::VisitComplexUnaryOperator(
   case UO_AddrOf:
     return this->delegate(SubExpr);
 
+  case UO_LNot:
+    if (!this->visit(SubExpr))
+      return false;
+    if (!this->emitComplexBoolCast(SubExpr))
+      return false;
+    if (!this->emitInvBool(E))
+      return false;
+    if (PrimType ET = classifyPrim(E->getType()); ET != PT_Bool)
+      return this->emitCast(PT_Bool, ET, E);
+    return true;
+
   case UO_Real:
     return this->emitComplexReal(SubExpr);
 

clang/test/AST/Interp/complex.c

@@ -14,3 +14,8 @@ void blah() {
 _Static_assert((0.0 + 0.0j) == (0.0 + 0.0j), "");
 _Static_assert((0.0 + 0.0j) != (0.0 + 0.0j), ""); // both-error {{static assertion}} \
                                                   // both-note {{evaluates to}}
+
+const _Complex float FC = {0.0f, 0.0f};
+_Static_assert(!FC, "");
+const _Complex float FI = {0, 0};
+_Static_assert(!FI, "");