diff --git a/libs/vkd3d-shader/hlsl_codegen.c b/libs/vkd3d-shader/hlsl_codegen.c
index 91f5646e8..f36ef06c1 100644
--- a/libs/vkd3d-shader/hlsl_codegen.c
+++ b/libs/vkd3d-shader/hlsl_codegen.c
@@ -6464,6 +6464,8 @@ static void allocate_semantic_register(struct hlsl_ctx *ctx, struct hlsl_ir_var
 
         if ((!output && !var->last_read) || (output && !var->first_write))
             return;
+
+        optimize = false;
     }
     else
     {