diff --git a/src/gpu/effects/GrConfigConversionEffect.cpp b/src/gpu/effects/GrConfigConversionEffect.cpp
index 972f07f..1067906 100644
--- a/src/gpu/effects/GrConfigConversionEffect.cpp
+++ b/src/gpu/effects/GrConfigConversionEffect.cpp
@@ -49,6 +49,9 @@
                     builder->fFSCode.appendf("\t%s = tempColor.a <= 0.0 ? vec4(0,0,0,0) : vec4(floor(tempColor.%s / tempColor.a * 255.0)/255.0, tempColor.a);\n",
                         outputColor, swiz);
                     break;
+                default:
+                    GrCrash("Unknown conversion op.");
+                    break;
             }
         }
     }