diff --git a/source/lib/sysdep/rtl/gcc/gcc.cpp b/source/lib/sysdep/rtl/gcc/gcc.cpp
index c01d3188df..8bca002088 100644
--- a/source/lib/sysdep/rtl/gcc/gcc.cpp
+++ b/source/lib/sysdep/rtl/gcc/gcc.cpp
@@ -28,7 +28,7 @@
 void* rtl_AllocateAligned(size_t size, size_t alignment)
 {
 	void *ptr;
-	int ret = posix_memalign(&ptr, size, alignment);
+	int ret = posix_memalign(&ptr, alignment, size);
 	if (ret) {
 		// TODO: report error?
 		return NULL;
@@ -72,7 +72,8 @@ void* rtl_AllocateAligned(size_t size, size_t align)
 
 void rtl_FreeAligned(void* alignedPointer)
 {
-	free(((void**)alignedPointer)[-1]);
+	if (alignedPointer)
+		free(((void**)alignedPointer)[-1]);
 }
 
 #endif
diff --git a/source/lib/sysdep/tests/test_rtl.h b/source/lib/sysdep/tests/test_rtl.h
new file mode 100644
index 0000000000..f52f83a19c
--- /dev/null
+++ b/source/lib/sysdep/tests/test_rtl.h
@@ -0,0 +1,49 @@
+/* Copyright (C) 2009 Wildfire Games.
+ * This file is part of 0 A.D.
+ *
+ * 0 A.D. is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 0 A.D. is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "lib/self_test.h"
+
+#include "lib/sysdep/rtl.h"
+
+class Test_rtl : public CxxTest::TestSuite
+{
+	void _test_AllocateAligned_helper(size_t size, size_t align)
+	{
+		void* p = rtl_AllocateAligned(size, align);
+		TS_ASSERT(p != NULL);
+		TS_ASSERT_EQUALS((intptr_t)p % align, 0u);
+		memset(p, 0x42, size);
+		rtl_FreeAligned(p);
+	}
+public:
+	void test_AllocateAligned()
+	{
+		for (size_t s = 0; s < 64; ++s)
+		{
+			_test_AllocateAligned_helper(s, 8);
+			_test_AllocateAligned_helper(s, 16);
+			_test_AllocateAligned_helper(s, 64);
+			_test_AllocateAligned_helper(s, 1024);
+			_test_AllocateAligned_helper(s, 65536);
+		}
+	}
+
+	void test_FreeAligned_null()
+	{
+		rtl_FreeAligned(NULL);
+	}
+};