r300: add just in case warn I don't think this can actually happen

diff --git a/src/mesa/drivers/dri/r300/r300_render.c b/src/mesa/drivers/dri/r300/r300_render.c
index 8e6b4967ef18373bf659af652ae44c8f7b2a1132..4bf09c2e89a501b7187dc1877ddbe26b12c8aeac 100644 (file)
--- a/src/mesa/drivers/dri/r300/r300_render.c
+++ b/src/mesa/drivers/dri/r300/r300_render.c
@@ -380,6 +380,11 @@ void r300RunRenderPrimitive(GLcontext * ctx, int start, int end, int prim)
                                    if (align % 4)
                                        nr -= incr;
                                } while(align % 4);
+                               if (nr <= 0) {
+                                       WARN_ONCE("did the impossible happen? we never aligned nr to dword\n");
+                                       return;
+                               }
+                                       
                        }
                        r300FireEB(rmesa, nr, type, offset);