From b96a48de58e1969535865b7b345514a24f7178a6 Mon Sep 17 00:00:00 2001
From: "nicolas.nardino" <nicolas.nardino@ens-lyon.fr>
Date: Mon, 28 Jun 2021 16:04:44 +0200
Subject: Change temporary solution (see prev commits), and add option for it

---
 driver/Clflags.ml                  |  1 +
 driver/Driver.ml                   |  2 ++
 scheduling/InstructionScheduler.ml | 21 +++++++++++++++++----
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/driver/Clflags.ml b/driver/Clflags.ml
index c90fdb8c..d01b57f0 100644
--- a/driver/Clflags.ml
+++ b/driver/Clflags.ml
@@ -116,4 +116,5 @@ let option_profile_arcs = ref false
 let option_fbranch_probabilities = ref true
 let option_debug_compcert = ref 0
 let option_regpres_threshold = ref 2
+let option_regpres_temp = ref false
 let main_function_name = ref "main"
diff --git a/driver/Driver.ml b/driver/Driver.ml
index 4f43d7c9..22c75f44 100644
--- a/driver/Driver.ml
+++ b/driver/Driver.ml
@@ -212,6 +212,7 @@ Processing options:
   -fprepass= <optim> Perform postpass scheduling with the specified optimization [list]
                    (<optim>=list: list scheduling, <optim>=revlist: reverse list scheduling, <optim>=regpres: list scheduling aware of register pressure, <optim>=regpres_bis: variant of regpres, <optim>=zigzag: zigzag scheduling, <optim>=ilp: ILP, <optim>=greedy: just packing bundles)
   -regpres-threshold n   With `-fprepass= regpres`, set threshold value for number of free registers before trying to decrease register pressure
+  -fregpres-temp  use the temporary solution (default no)
   -fpostpass     Perform postpass scheduling (only for K1 architecture) [on] 
   -fpostpass= <optim> Perform postpass scheduling with the specified optimization [list]
                    (<optim>=list: list scheduling, <optim>=ilp: ILP, <optim>=greedy: just packing bundles)
@@ -426,6 +427,7 @@ let cmdline_actions =
   @ f_opt "redundancy" option_fredundancy
   @ [ Exact "-mtune", String (fun s -> option_mtune := s) ]
   @ f_opt "prepass" option_fprepass
+  @ f_opt "regpres-temp" option_regpres_temp
   @ f_opt "postpass" option_fpostpass
   @ [ Exact "-ftailduplicate", Integer (fun n -> option_ftailduplicate := n) ]
   @ f_opt "predict" option_fpredict
diff --git a/scheduling/InstructionScheduler.ml b/scheduling/InstructionScheduler.ml
index e2413bc0..a881df68 100644
--- a/scheduling/InstructionScheduler.ml
+++ b/scheduling/InstructionScheduler.ml
@@ -486,7 +486,7 @@ let reg_pres_scheduler (problem : problem) : solution option =
 
   (* ALL MENTIONS TO cnt ARE PLACEHOLDERS *)
   let cnt = ref 0 in
-  
+
   let attempt_scheduling ready usages =
     let result = ref (-1) in
     try
@@ -500,7 +500,7 @@ let reg_pres_scheduler (problem : problem) : solution option =
            * print_int (Hashtbl.length live_regs);
            * print_newline ();
            * flush stdout; *)
-          if !cnt < 5 && avlregs <= regs_thresholds.(i)
+          if avlregs <= regs_thresholds.(i)
           then (
             let maybe = InstrSet.sched_CSR i ready usages in
             (* print_string "maybe\n";
@@ -518,7 +518,19 @@ let reg_pres_scheduler (problem : problem) : solution option =
              then
                (vector_subtract usages.(maybe) current_resources;
                 result := maybe)
-             else incr cnt);
+             else
+               if not !Clflags.option_regpres_temp
+               then
+                 (InstrSet.iter (fun ins ->
+                      if vector_less_equal usages.(ins) current_resources &&
+                           List.fold_left (fold_delta i) 0 mentions.(maybe) >= 0
+                      then result := ins
+                    ) ready;
+                  if !result <> -1 then
+                    vector_subtract usages.(!result) current_resources)
+               else
+                 (incr cnt)
+            );
             raise Exit)) available_regs;
       InstrSet.iter (fun i ->
           if vector_less_equal usages.(i) current_resources
@@ -543,7 +555,8 @@ let reg_pres_scheduler (problem : problem) : solution option =
               * print_int i;
               * print_newline ();
               * flush stdout; *)
-             cnt := 0;
+             if !Clflags.option_regpres_temp then
+               cnt := 0;
              List.iter (fun (r,b) ->
                  if b then
                    (match Hashtbl.find_opt counts r with
-- 
cgit