diff --git a/libs/vkd3d-shader/ir.c b/libs/vkd3d-shader/ir.c
index c61cf95a6..6ff9c4b3b 100644
--- a/libs/vkd3d-shader/ir.c
+++ b/libs/vkd3d-shader/ir.c
@@ -9995,6 +9995,7 @@ struct vsir_validator_instruction_desc
 static const struct vsir_validator_instruction_desc vsir_validator_instructions[] =
 {
     [VKD3DSIH_ABS] =                              {1,   1, vsir_validate_float_elementwise_operation},
+    [VKD3DSIH_ACOS] =                             {1,   1, vsir_validate_float_elementwise_operation},
     [VKD3DSIH_BRANCH] =                           {0, ~0u, vsir_validate_branch},
     [VKD3DSIH_HS_CONTROL_POINT_PHASE] =           {0,   0, vsir_validate_hull_shader_phase},
     [VKD3DSIH_HS_DECLS] =                         {0,   0, vsir_validate_hull_shader_phase},