empty graph rewrite to VIZ tensor graph [pr] (#8658)

* empty graph rewrite to VIZ tensor graph [pr]

* fix lint

tinygrad/engine/schedule.py

@@ -519,9 +519,12 @@ remove_movement_ops = PatternMatcher([
 
 @track_rewrites(named=True)
 def create_schedule_with_vars(outs:list[UOp], skip_check:bool=not __debug__) -> tuple[list[ScheduleItem], dict[Variable, int], dict[UOp, UOp]]:
-  if not skip_check: type_verify(list(UOp.sink(*outs).toposort), tensor_uop_spec)
+  big_sink = UOp.sink(*outs)
+  # if using VIZ, do an empty graph rewrite to vizualize the Tensor graph
+  if getenv("VIZ"): graph_rewrite(big_sink, PatternMatcher([]))
+  if not skip_check: type_verify(list(big_sink.toposort), tensor_uop_spec)
   # to_uop is removing (many) of the movement ops
-  sink = add_buffers(UOp.sink(*outs), ctx:=ScheduleContext(), cache={})
+  sink = add_buffers(big_sink, ctx:=ScheduleContext(), cache={})
   # const folding and fusion
   sink = graph_rewrite(sink, remove_movement_ops+ops_folding+do_realize, ctx)
   sink = graph_rewrite(sink, merge_bufs, ctx)

tinygrad/viz/serve.py

@@ -73,7 +73,7 @@ def uop_to_json(x:UOp) -> dict[int, tuple[str, str, list[int], str, str]]:
     if u.op is Ops.VIEW:
       argst = ("\n".join([f"{v.shape} / {v.strides}"+(f"\nMASK {v.mask}" if v.mask is not None else "")+
                           ("" if v.offset == 0 else f" / {v.offset}") for v in unwrap(u.st).views]))
-    label = f"{str(u.op).split('.')[1]}{(' '+word_wrap(argst.replace(':', ''))) if u.arg is not None else ''}\n{str(u.dtype)}"
+    label = f"{str(u.op).split('.')[1]}{(chr(10)+word_wrap(argst.replace(':', ''))) if u.arg is not None else ''}\n{str(u.dtype)}"
     for idx,x in enumerate(u.src):
       if x in excluded:
         if x.op is Ops.CONST and dtypes.is_float(u.dtype): label += f"\nCONST{idx} {x.arg:g}"