diff --git a/source/lib/bits.h b/source/lib/bits.h
index 92a5afb27e..dd1ac9b54c 100644
--- a/source/lib/bits.h
+++ b/source/lib/bits.h
@@ -51,7 +51,7 @@ T bit_mask(size_t numBits)
 	// note: the perhaps more intuitive (1 << numBits)-1 cannot
 	// handle numBits == bitsInT, but this implementation does.
 	const T bitsInT = sizeof(T)*CHAR_BIT;
-	T mask = ~T(0);
+	T mask = T(~0);
 	mask >>= T(bitsInT-numBits);
 	return mask;
 }
@@ -111,7 +111,8 @@ bool is_pow2(T n)
  * ceil(log2(x))
  *
  * @param x (unsigned integer)
- * @return ceiling of the base-2 logarithm (i.e. rounded up).
+ * @return ceiling of the base-2 logarithm (i.e. rounded up) or
+ * zero if the input is zero.
  **/
 template<typename T>
 size_t ceil_log2(T x)
diff --git a/source/lib/sysdep/cpu.h b/source/lib/sysdep/cpu.h
index 30e8d9a5ae..6dffc2a831 100644
--- a/source/lib/sysdep/cpu.h
+++ b/source/lib/sysdep/cpu.h
@@ -64,11 +64,6 @@ LIB_API void cpu_AtomicAdd(volatile intptr_t* location, intptr_t increment);
  **/
 LIB_API void cpu_Serialize();
 
-/**
- * enforce strong memory ordering.
- **/
-LIB_API void cpu_MemoryFence();
-
 
 //-----------------------------------------------------------------------------
 // misc
diff --git a/source/lib/sysdep/win/wdbg_heap.cpp b/source/lib/sysdep/win/wdbg_heap.cpp
index 9c27fe8eec..7bd640d646 100644
--- a/source/lib/sysdep/win/wdbg_heap.cpp
+++ b/source/lib/sysdep/win/wdbg_heap.cpp
@@ -823,7 +823,7 @@ static void PrintCallStack(const uintptr_t* callers, size_t numCallers)
 	}
 }
 
-
+#ifndef NDEBUG
 static int __cdecl ReportHook(int reportType, char* message, int* out)
 {
 	UNUSED2(reportType);
@@ -886,6 +886,7 @@ static int __cdecl ReportHook(int reportType, char* message, int* out)
 	wdbg_assert(0);	// unreachable
 	return 0;
 }
+#endif
 
 //-----------------------------------------------------------------------------
 
diff --git a/source/lib/sysdep/x86_x64/x86_x64.cpp b/source/lib/sysdep/x86_x64/x86_x64.cpp
index c307b1b2bf..aa16ffdb9a 100644
--- a/source/lib/sysdep/x86_x64/x86_x64.cpp
+++ b/source/lib/sysdep/x86_x64/x86_x64.cpp
@@ -509,14 +509,6 @@ void x86_x64_DebugBreak()
 }
 
 
-// enforce strong memory ordering.
-void cpu_MemoryFence()
-{
-	if(x86_x64_cap(X86_X64_CAP_SSE2))
-		_mm_mfence();
-}
-
-
 void cpu_Serialize()
 {
 	x86_x64_CpuidRegs regs;
diff --git a/source/lib/tests/test_bits.h b/source/lib/tests/test_bits.h
index 27e65d2d0a..332a8c63de 100644
--- a/source/lib/tests/test_bits.h
+++ b/source/lib/tests/test_bits.h
@@ -33,9 +33,9 @@ public:
 	void test_round_up_to_pow2()
 	{
 		TS_ASSERT_EQUALS(round_up_to_pow2(0u), 1u);
-		TS_ASSERT_EQUALS(round_up_to_pow2(1u), 2u);
+		TS_ASSERT_EQUALS(round_up_to_pow2(1u), 1u);
 		TS_ASSERT_EQUALS(round_up_to_pow2(127u), 128u);
-		TS_ASSERT_EQUALS(round_up_to_pow2(128u), 256u);
+		TS_ASSERT_EQUALS(round_up_to_pow2(128u), 128u);
 		TS_ASSERT_EQUALS(round_up_to_pow2(129u), 256u);
 	}
 
diff --git a/source/renderer/TerrainOverlay.h b/source/renderer/TerrainOverlay.h
index 2d0d3c507f..87707bfbb2 100644
--- a/source/renderer/TerrainOverlay.h
+++ b/source/renderer/TerrainOverlay.h
@@ -10,12 +10,12 @@
 #ifndef INCLUDED_TERRAINOVERLAY
 #define INCLUDED_TERRAINOVERLAY
 
-class CColor;
+struct CColor;
 class CTerrain;
 
 /**
  * Base class for (relatively) simple drawing of
- * data onto terrain tiles, ssize_tended for debugging purposes and for the Atlas
+ * data onto terrain tiles, intended for debugging purposes and for the Atlas
  * editor (hence not trying to be very efficient).
  * <p>
  * To start drawing a terrain overlay, first create a subclass of TerrainOverlay.