attempt at "zigzag" scheduler; not quite testable due to issues in the duplicate/linearize passes

2 files changed, 36 insertions, 1 deletions

diff --git a/scheduling/InstructionScheduler.mli b/scheduling/InstructionScheduler.mli
index 85e2a5c6..fb7af3f6 100644
--- a/scheduling/InstructionScheduler.mli
+++ b/scheduling/InstructionScheduler.mli
@@ -33,6 +33,12 @@ type problem = {
 (** Print problem for human readability. *)
 val print_problem : out_channel -> problem -> unit;;
 
+(** Get the number of instructions in a problem *)
+val get_nr_instructions : problem -> int;;
+
+(** Get the number of resources in a problem *)
+val get_nr_resources : problem -> int;;
+
 (** Scheduling solution. For {i n} instructions to schedule, and 0≤{i i}<{i n}, position {i i} contains the time to which instruction {i i} should be scheduled. Position {i n} contains the final output latency. *)
 type solution = int array
               
diff --git a/scheduling/PrepassSchedulingOracle.ml b/scheduling/PrepassSchedulingOracle.ml
index 78961310..7b7b7233 100644
--- a/scheduling/PrepassSchedulingOracle.ml
+++ b/scheduling/PrepassSchedulingOracle.ml
@@ -403,6 +403,29 @@ let define_problem seqa =
       then (get_alias_dependencies seqa) @ simple_deps
       else *) simple_deps };;
 
+let zigzag_scheduler problem early_ones =
+  let nr_instructions = get_nr_instructions problem in
+  assert(nr_instructions = (Array.length early_ones));
+  match list_scheduler problem with
+  | Some fwd_schedule ->
+     let fwd_makespan = fwd_schedule.((Array.length fwd_schedule) - 1) in
+     let constraints' = ref problem.latency_constraints in
+     Array.iteri (fun i is_early ->
+         if is_early then
+           constraints' :=  {
+             instr_from = i;
+             instr_to = nr_instructions ;
+             latency = fwd_makespan - fwd_schedule.(i) } ::!constraints' )
+       early_ones;
+     validated_scheduler reverse_list_scheduler
+       { problem with latency_constraints = !constraints' }
+  | None -> None;;
+  
+let prepass_scheduler_by_name name problem early_ones =
+  match name with
+  | "zigzag" -> zigzag_scheduler problem early_ones
+  | _ -> scheduler_by_name name problem
+  
 let schedule_sequence (seqa : (instruction*Regset.t) array) =
   try
     if (Array.length seqa) <= 1
@@ -414,7 +437,13 @@ let schedule_sequence (seqa : (instruction*Regset.t) array) =
       let problem = define_problem seqa in
       print_sequence stdout (Array.map fst seqa);
       print_problem stdout problem;
-      match scheduler_by_name (!Clflags.option_fprepass_sched) problem with
+      match prepass_scheduler_by_name
+              (!Clflags.option_fprepass_sched)
+              problem
+              (Array.map (fun (ins, _) ->
+                   match ins with
+                   | Icond _ -> true
+                   | _ -> false) seqa) with
       | None -> Printf.printf "no solution in prepass scheduling\n";
                 None
       | Some solution ->