diff --git a/cpp/src/codegen.cpp b/cpp/src/codegen.cpp
index 973cb4d..b01b44a 100644
--- a/cpp/src/codegen.cpp
+++ b/cpp/src/codegen.cpp
@@ -637,11 +637,11 @@ namespace codegen
 			case lexer::token::type::plus:
 				if(lhs_value.ty.is_floating_point_type())
 				{
-					ret.llv = builder->CreateFAdd(lhs_value.llv, rhs_value.llv);
+					ret.llv = builder->CreateFAdd(lhs_value.llv, load_as(rhs_value.llv, d.state, rhs_value.ty, lhs_value.ty));
 				}
 				else if(lhs_value.ty.is_integer_type())
 				{
-					ret.llv = builder->CreateAdd(lhs_value.llv, rhs_value.llv);
+					ret.llv = builder->CreateAdd(lhs_value.llv, load_as(rhs_value.llv, d.state, rhs_value.ty, lhs_value.ty));
 				}
 				else
 				{
@@ -653,11 +653,11 @@ namespace codegen
 			case lexer::token::type::minus:
 				if(lhs_value.ty.is_floating_point_type())
 				{
-					ret.llv = builder->CreateFSub(lhs_value.llv, rhs_value.llv);
+					ret.llv = builder->CreateFSub(lhs_value.llv, load_as(rhs_value.llv, d.state, rhs_value.ty, lhs_value.ty));
 				}
 				else if(lhs_value.ty.is_integer_type())
 				{
-					ret.llv = builder->CreateSub(lhs_value.llv, rhs_value.llv);
+					ret.llv = builder->CreateSub(lhs_value.llv, load_as(rhs_value.llv, d.state, rhs_value.ty, lhs_value.ty));
 				}
 				else
 				{
@@ -1364,6 +1364,24 @@ namespace codegen
 			type ty = this->state.try_get_type_from_payload(ptr_expr, this->tree, this->path);
 			ret = string_literal(*this, {.val = ty.name()});
 		}
+		if(call.function_name == "__builtin_sizeof")
+		{
+			this->assert_that(call.params.size() == 1, "__builtin_typename requires one argument.");
+			const ast::expression& ptr_expr = call.params.front();
+			// if you call any codegen functions, you will uh... generate code.
+			// we *must* only rely on semantic analysis here.
+			type ty = type::undefined();
+			if(std::holds_alternative<ast::identifier>(ptr_expr.expr))
+			{
+				ty = this->state.get_type_from_name(std::get<ast::identifier>(ptr_expr.expr).name).first;
+			}
+			if(ty.is_undefined())
+			{
+				ty = this->state.try_get_type_from_payload(ptr_expr, this->tree, this->path);
+			}
+			int size = program->getDataLayout().getTypeAllocSize(as_llvm_type(ty, state));
+			ret = integer_literal(*this, {.val = size});
+		}
 		return ret;
 	}
 }
\ No newline at end of file
diff --git a/samples/scratchpad.psy b/samples/scratchpad.psy
index b9406d7..429013d 100644
--- a/samples/scratchpad.psy
+++ b/samples/scratchpad.psy
@@ -17,7 +17,7 @@ triangle : struct
 
 main : (argc : i64, argv : i8**) -> i64
 {
-	shape_ptr : triangle* = default_malloc(64);
+	shape_ptr : triangle* = default_malloc(__builtin_sizeof(triangle));
 	defer default_free(shape_ptr);
 	= shape_ptr->base 'A';
 	= shape_ptr->height 19;