Remove Linearize Pass

.github/workflows/build.yml

@@ -63,11 +63,6 @@ jobs:
             ocamlparam: '_,Oclassic=1'
             disable_testcases: 'ocaml/testsuite/tests/typing-local/regression_cmm_unboxing.ml ocaml/testsuite/tests/int64-unboxing/test.ml'
 
-          - name: flambda2_no_cfg
-            config: --enable-middle-end=flambda2
-            os: ubuntu-latest
-            build_ocamlparam: _,ocamlcfg=0
-
           - name: flambda2_macos
             config: --enable-middle-end=flambda2
             os: macos-latest

backend/asmgen.ml

@@ -152,8 +152,6 @@ let write_ir prefix =
     Linear_format.save filename linear_unit_info
   end;
   if should_save_cfg_before_emit () then begin
-    if not !Flambda_backend_flags.use_ocamlcfg then
-      Misc.fatal_error "Flag '-save-ir-after simplify_cfg' requires '-ocamlcfg'";
     let filename = Compiler_pass.(to_output_filename Simplify_cfg ~prefix) in
     cfg_unit_info.items <- List.rev cfg_unit_info.items;
     Cfg_format.save filename cfg_unit_info
@@ -346,24 +344,17 @@ let compile_fundecl ~ppf_dump ~funcnames fd_cmm =
             else Available_regs.fundecl fundecl)
         ++ pass_dump_if ppf_dump Flambda_backend_flags.davail
              "Register availability analysis"
-        ++ Profile.record ~accumulate:true "mach to linear" (fun (fd : Mach.fundecl) ->
-          if !Flambda_backend_flags.use_ocamlcfg then begin
-            fd
-            ++ Profile.record ~accumulate:true "cfgize"
-                 (Cfgize.fundecl
-                    ~before_register_allocation:false
-                    ~preserve_orig_labels:false
-                    ~simplify_terminators:true)
-            ++ Compiler_hooks.execute_and_pipe Compiler_hooks.Cfg
-            ++ pass_dump_cfg_if ppf_dump Flambda_backend_flags.dump_cfg "After linear_to_cfg"
-            ++ Profile.record ~accumulate:true "save_cfg" save_cfg
-            ++ Profile.record ~accumulate:true "cfg_reorder_blocks"
-                 (reorder_blocks_random ppf_dump)
-            ++ Profile.record ~accumulate:true "cfg_to_linear" Cfg_to_linear.run
-          end else begin
-            fd
-            ++ Profile.record ~accumulate:true "linearize" Linearize.fundecl
-          end))
+        ++ Profile.record ~accumulate:true "cfgize"
+             (Cfgize.fundecl
+                ~before_register_allocation:false
+                ~preserve_orig_labels:false
+                ~simplify_terminators:true)
+        ++ Compiler_hooks.execute_and_pipe Compiler_hooks.Cfg
+        ++ pass_dump_cfg_if ppf_dump Flambda_backend_flags.dump_cfg "After cfgize"
+        ++ Profile.record ~accumulate:true "save_cfg" save_cfg
+        ++ Profile.record ~accumulate:true "cfg_reorder_blocks"
+             (reorder_blocks_random ppf_dump)
+        ++ Profile.record ~accumulate:true "cfg_to_linear" Cfg_to_linear.run)
   ++ pass_dump_linear_if ppf_dump dump_linear "Linearized code")
   ++ Compiler_hooks.execute_and_pipe Compiler_hooks.Linear
   ++ Profile.record ~accumulate:true "scheduling" Scheduling.fundecl

backend/cfg/cfg.mli

@@ -154,14 +154,10 @@ val print_instruction :
    exception handling. It has a lot of redundancy and the result of the
    computation is not used.
 
-   Redundancy: linear_to_cfg reconstructs intraprocedural exception handling
-   stacks from linear IR and annotates each block with this information.
-   However, CFG instructions still include the original push/poptraps from
-   Linear.
-
-   To remove these push/poptraps from CFG IR, we need to split blocks at every
-   push/poptrap. Then, we can annotate the blocks with the top of the trap
-   stack, instead of carrying the copy of the stack. *)
+   CFG instructions still include push/poptraps. To remove these push/poptraps
+   from CFG IR, we need to split blocks at every push/poptrap. Then, we can
+   annotate the blocks with the top of the trap stack, instead of carrying the
+   copy of the stack. *)
 
 (* CR-someday gyorsh: store label after separately and update after
    reordering. *)

backend/cfg/cfgize.ml

@@ -784,8 +784,7 @@ let fundecl :
         fun_contains_calls;
         (* CR-someday mshinwell: [fun_poll] will need to be propagated in the
            future, e.g. when writing a [Polling] equivalent on [Cfg]. We don't
-           do this at present since there is no need, and because
-           [Linear_to_cfg] doesn't have [fun_poll] available. *)
+           do this at present since there is no need. *)
         fun_poll = _
       } =
     fundecl