Index: /trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp
===================================================================
--- /trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp	(revision 81193)
+++ /trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp	(revision 81194)
@@ -3585,5 +3585,5 @@
             STAM_REL_COUNTER_INC(&pSVGAState->StatFifoErrors);
             LogRelMax(8, ("vmsvgaFIFOLoop: Misaligned offCurrentCmd=%#x?\n", offCurrentCmd));
-            offCurrentCmd = ~UINT32_C(3);
+            offCurrentCmd &= ~UINT32_C(3);
         }
 
@@ -4342,7 +4342,8 @@
  */
 #  define VMSVGAFIFO_CHECK_3D_CMD_MIN_SIZE_BREAK(a_cbMin) \
-     do { AssertMsgBreak(pHdr->size >= (a_cbMin), ("size=%#x a_cbMin=%#zx\n", pHdr->size, (size_t)(a_cbMin))); \
+     if (1) { \
+          AssertMsgBreak(pHdr->size >= (a_cbMin), ("size=%#x a_cbMin=%#zx\n", pHdr->size, (size_t)(a_cbMin))); \
           RT_UNTRUSTED_VALIDATED_FENCE(); \
-     } while (0)
+     } else do {} while (0)
                     switch ((int)enmCmdId)
                     {