diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index 2aeaf9a6a65..f12dbd37d38 100644
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -2414,6 +2414,9 @@ static inline void callstack_check_depth(struct r600_shader_ctx *ctx, unsigned r
 		case FC_PUSH_WQM:
 			diff = 4;
 			break;
+		default:
+			assert(0);
+			diff = 0;
 		}
 		if ((ctx->bc->callstack[ctx->bc->call_sp].current + diff) >
 		    ctx->bc->callstack[ctx->bc->call_sp].max) {