flambda-backend: Bypass Simplify (#162)

Author: Keryan-dev

utils/clflags.ml

@@ -459,6 +459,7 @@ end
 
 module Flambda2 = struct
   module Default = struct
+    let classic_mode = false
     let join_points = true
     let unbox_along_intra_function_control_flow = true
     let backend_cse_at_toplevel = false
@@ -467,6 +468,7 @@ module Flambda2 = struct
     let unicode = true
   end
 
+  let classic_mode = ref Default.classic_mode
   let join_points = ref Default.join_points
   let unbox_along_intra_function_control_flow =
     ref Default.unbox_along_intra_function_control_flow
@@ -628,6 +630,7 @@ module Flambda2 = struct
   end
 
   let oclassic_flags () =
+    classic_mode := true;
     cse_depth := 2;
     join_points := false;
     unbox_along_intra_function_control_flow := true;

utils/clflags.mli

@@ -216,6 +216,7 @@ val insn_sched_default : bool
 
 module Flambda2 : sig
   module Default : sig
+    val classic_mode : bool
     val join_points : bool
     val unbox_along_intra_function_control_flow : bool
     val backend_cse_at_toplevel : bool
@@ -225,6 +226,7 @@ module Flambda2 : sig
     val unicode : bool
   end
 
+  val classic_mode : bool ref
   val join_points : bool ref
   val unbox_along_intra_function_control_flow : bool ref
   val backend_cse_at_toplevel : bool ref