diff --git a/src/intel/vulkan/genX_pipeline.c b/src/intel/vulkan/genX_pipeline.c
index 9afcddf7568..a104b032271 100644
--- a/src/intel/vulkan/genX_pipeline.c
+++ b/src/intel/vulkan/genX_pipeline.c
@@ -185,6 +185,7 @@ genX(emit_vertex_input)(struct anv_batch *batch,
                                                   vi->attributes[a].format,
                                                   VK_IMAGE_ASPECT_COLOR_BIT,
                                                   VK_IMAGE_TILING_LINEAR);
+      assume(format < ISL_NUM_FORMATS);
 
       uint32_t binding = vi->attributes[a].binding;
       assert(binding < MAX_VBS);