diff --git a/pym/portage/package/ebuild/config.py b/pym/portage/package/ebuild/config.py
index 5ede061..67f95de 100644
--- a/pym/portage/package/ebuild/config.py
+++ b/pym/portage/package/ebuild/config.py
@@ -2313,22 +2313,22 @@
 					if v is None:
 						continue
 					prefix = k.lower() + '_'
-					if k in myincrementals:
-						for x in v.split():
-							if x[:1] == '-':
-								expand_use.append('-' + prefix + x[1:])
-							else:
-								expand_use.append(prefix + x)
-					else:
-						for x in v.split():
+					for x in v.split():
+						if x[:1] == '-':
+							expand_use.append('-' + prefix + x[1:])
+						else:
 							expand_use.append(prefix + x)
+
 				if expand_use:
 					expand_use.append(use)
 					use  = ' '.join(expand_use)
 				self.make_defaults_use.append(use)
 			self.make_defaults_use = tuple(self.make_defaults_use)
+			# Preserve both positive and negative flags here, since
+			# negative flags may later interact with other flags pulled
+			# in via USE_ORDER.
 			configdict_defaults['USE'] = ' '.join(
-				stack_lists([x.split() for x in self.make_defaults_use]))
+				filter(None, self.make_defaults_use))
 			# Set to None so this code only runs once.
 			self._make_defaults = None
 
diff --git a/pym/portage/tests/ebuild/test_use_expand_incremental.py b/pym/portage/tests/ebuild/test_use_expand_incremental.py
new file mode 100644
index 0000000..a58f08c
--- /dev/null
+++ b/pym/portage/tests/ebuild/test_use_expand_incremental.py
@@ -0,0 +1,132 @@
+# Copyright 2014 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+from __future__ import unicode_literals
+
+import io
+
+from portage import os, _encodings
+from portage.dep import Atom
+from portage.package.ebuild.config import config
+from portage.tests import TestCase
+from portage.tests.resolver.ResolverPlayground import ResolverPlayground
+from portage.util import ensure_dirs
+
+class UseExpandIncrementalTestCase(TestCase):
+
+	def testUseExpandIncremental(self):
+
+		profiles = (
+			(
+				'base',
+				{
+					"eapi": ("5",),
+					"parent": ("..",),
+					"make.defaults": (
+						"INPUT_DEVICES=\"keyboard mouse\"",
+						"PYTHON_TARGETS=\"python2_7 python3_3\"",
+						("USE_EXPAND=\"INPUT_DEVICES PYTHON_TARGETS "
+							"VIDEO_CARDS\""),
+					)
+				}
+			),
+			(
+				'default/linux',
+				{
+					"eapi": ("5",),
+					"make.defaults": (
+						"VIDEO_CARDS=\"dummy fbdev v4l\"",
+					)
+				}
+			),
+			(
+				'default/linux/x86',
+				{
+					"eapi": ("5",),
+					"make.defaults": (
+						# Test negative incremental for bug 530222.
+						"PYTHON_TARGETS=\"-python3_3\"",
+					),
+					"parent": ("../../../base",
+						"../../../mixins/python/3.4",
+						".."
+					)
+				}
+			),
+			(
+				'mixins/python/3.4',
+				{
+					"eapi": ("5",),
+					"make.defaults": (
+						"PYTHON_TARGETS=\"python3_4\"",
+					)
+				}
+			),
+		)
+
+		# USE_EXPAND variable settings in make.conf will cause
+		# profile settings for the same variable to be discarded
+		# (non-incremental behavior). PMS does not govern make.conf
+		# behavior.
+		user_config = {
+			"make.conf" : (
+				"VIDEO_CARDS=\"intel\"",
+			)
+		}
+
+		ebuilds = {
+			"x11-base/xorg-drivers-1.15": {
+				"EAPI": "5",
+				"IUSE": ("input_devices_keyboard input_devices_mouse "
+					"videos_cards_dummy video_cards_fbdev "
+					"video_cards_v4l video_cards_intel")
+			},
+			"sys-apps/portage-2.2.14": {
+				"EAPI": "5",
+				"IUSE": ("python_targets_python2_7 "
+					"python_targets_python3_3 python_targets_python3_4")
+			},
+		}
+
+		package_expected_use = (
+			("x11-base/xorg-drivers-1.15", ("input_devices_keyboard",
+				"input_devices_mouse", "video_cards_intel",)),
+			("sys-apps/portage-2.2.14", ("python_targets_python2_7",
+				"python_targets_python3_4"))
+		)
+
+		playground = ResolverPlayground(debug=False,
+			ebuilds=ebuilds, user_config=user_config)
+		try:
+			repo_dir = (playground.settings.repositories.
+				get_location_for_name("test_repo"))
+			profile_root = os.path.join(repo_dir, "profiles")
+
+			for p, data in profiles:
+				prof_path = os.path.join(profile_root, p)
+				ensure_dirs(prof_path)
+				for k, v in data.items():
+					with io.open(os.path.join(prof_path, k), mode="w",
+						encoding=_encodings["repo.content"]) as f:
+						for line in v:
+							f.write("%s\n" % line)
+
+			# The config must be reloaded in order to account
+			# for the above profile customizations.
+			playground.reload_config()
+
+			depgraph = playground.run(
+				["=x11-base/xorg-drivers-1.15"]).depgraph
+			settings = config(clone=playground.settings)
+
+			for cpv, expected_use in package_expected_use:
+				pkg, existing_node = depgraph._select_package(
+					playground.eroot, Atom("=" + cpv))
+				settings.setcpv(pkg)
+				expected = frozenset(expected_use)
+				got = frozenset(settings["PORTAGE_USE"].split())
+				self.assertEqual(got, expected,
+					"%s != %s" % (got, expected))
+
+		finally:
+			playground.cleanup()
diff --git a/pym/portage/tests/resolver/ResolverPlayground.py b/pym/portage/tests/resolver/ResolverPlayground.py
index 077e271..6fcef5c 100644
--- a/pym/portage/tests/resolver/ResolverPlayground.py
+++ b/pym/portage/tests/resolver/ResolverPlayground.py
@@ -99,6 +99,16 @@
 
 		portage.util.noiselimit = 0
 
+	def reload_config(self):
+		"""
+		Reload configuration from disk, which is useful if it has
+		been modified after the constructor has been called.
+		"""
+		for eroot in self.trees:
+			portdb = self.trees[eroot]["porttree"].dbapi
+			portdb.close_caches()
+		self.settings, self.trees = self._load_config()
+
 	def _get_repo_dir(self, repo):
 		"""
 		Create the repo directory if needed.