diff --git a/compiler/mercury_compile_augment.m b/compiler/mercury_compile_augment.m
index 3d5559d64..0651da9e7 100644
--- a/compiler/mercury_compile_augment.m
+++ b/compiler/mercury_compile_augment.m
@@ -300,8 +300,7 @@ process_augmented_module_after_front_end(ProgressStream, ErrorStream, Globals,
!DumpInfo, !MaybeWrittenSpecs, !IO) :-
globals.lookup_bool_option(Globals, verbose, Verbose),
globals.lookup_bool_option(Globals, statistics, Stats),
- maybe_write_dependency_graph(ProgressStream, Stats,
- HLDS20, HLDS21, !IO),
+ maybe_write_dependency_graph(ProgressStream, Stats, HLDS20, HLDS21, !IO),
(
OpModeAugment = opmau_typecheck_only,
ExtraObjFiles = []
diff --git a/compiler/mercury_compile_front_end.m b/compiler/mercury_compile_front_end.m
index b2bff2cce..136a67133 100644
--- a/compiler/mercury_compile_front_end.m
+++ b/compiler/mercury_compile_front_end.m
@@ -34,7 +34,6 @@
:- import_module bool.
:- import_module io.
:- import_module list.
-:- import_module maybe.
%---------------------------------------------------------------------------%
@@ -44,53 +43,6 @@
dump_info::in, dump_info::out,
maybe_written_specs::in, maybe_written_specs::out, io::di, io::uo) is det.
-%---------------------------------------------------------------------------%
-
- % This type indicates what stage of compilation we are running
- % the simplification pass at. The exact simplifications tasks we run
- % will depend upon this.
- %
-:- type simplify_pass
- ---> simplify_pass_frontend
- % Running simplification immediately after all the semantic
- % analysis passes in the frontend. As of 2025 sep 13,
- % this is stage 65.
-
- ; simplify_pass_post_untuple
- % Running simplification after the untupling transformation
- % has been applied. As of 2025 sep 13, this is stage 133.
-
- ; simplify_pass_pre_implicit_parallelism
- % Running simplification before the implicit parallelism
- % transformation, if it is enabled. This helps ensure that
- % the HLDS matches the feedback data. As of 2025 sep 13,
- % this is stage 172.
-
- ; simplify_pass_pre_prof_transforms
- % Running simplification before either the term size profiling
- % or the profiling transformation, if either is enabled.
- % The reason for this pass is mainly to make up for the fact
- % that some simplifications that we can do using standard code
- % before these transforms would require more complex analysis,
- % if they were possible at all, after these transforms,
- % due to their introduction of e.g. impure code into the HLDS.
- % As of 2025 sep 13, this is stage 215.
-
- ; simplify_pass_ll_backend
- % One of the passes of the LLDS backend. As of 2025 sep 13,
- % this is stage 325.
-
- ; simplify_pass_ml_backend.
- % The first pass of the MLDS backend. As of 2025 sep 13,
- % this is stage 405.
-
- % This predicate sets up and maybe runs the simplification pass.
- %
-:- pred maybe_simplify(io.text_output_stream::in,
- maybe(io.text_output_stream)::in, bool::in, simplify_pass::in,
- bool::in, bool::in, module_info::in, module_info::out,
- maybe_written_specs::in, maybe_written_specs::out, io::di, io::uo) is det.
-
%---------------------------------------------------------------------------%
%---------------------------------------------------------------------------%
@@ -115,9 +67,6 @@
:- import_module check_hlds.post_typecheck.
:- import_module check_hlds.pre_typecheck.
:- import_module check_hlds.purity.
-:- import_module check_hlds.simplify.
-:- import_module check_hlds.simplify.simplify_proc.
-:- import_module check_hlds.simplify.simplify_tasks.
:- import_module check_hlds.stratify.
:- import_module check_hlds.style_checks.
:- import_module check_hlds.switch_detection.
@@ -131,8 +80,6 @@
:- import_module hlds.goal_mode.
:- import_module hlds.hlds_call_tree.
:- import_module hlds.hlds_clauses.
-:- import_module hlds.hlds_pred.
-:- import_module hlds.hlds_pred_tests.
:- import_module hlds.hlds_statistics.
:- import_module hlds.implementation_defined_literals.
:- import_module hlds.input_specialization.
@@ -152,6 +99,7 @@
:- import_module parse_tree.prog_data.
:- import_module parse_tree.write_error_spec.
:- import_module top_level.mercury_compile_middle_passes.
+:- import_module top_level.mercury_compile_simplify.
:- import_module transform_hlds.
:- import_module transform_hlds.dead_proc_elim.
:- import_module transform_hlds.intermod.
@@ -160,8 +108,8 @@
:- import_module benchmarking.
:- import_module map.
+:- import_module maybe.
:- import_module pair.
-:- import_module require.
:- import_module set.
:- import_module string.
:- import_module string.builder.
@@ -334,16 +282,6 @@ frontend_pass_after_typecheck(ProgressStream, ErrorStream, OpModeAugment,
(
OpModeAugment = opmau_typecheck_only
;
- % Switch detection looks at only a maximum of two levels
- % of disjunction, not three, so we need this block here;
- % the block that sets MakeOptInt is not recognized as
- % being a switch arm complementing the opmau_typecheck_only arm.
- ( OpModeAugment = opmau_make_plain_opt
- ; OpModeAugment = opmau_make_trans_opt
- ; OpModeAugment = opmau_make_analysis_registry
- ; OpModeAugment = opmau_make_xml_documentation
- ; OpModeAugment = opmau_front_and_middle(_)
- ),
(
OpModeAugment = opmau_make_plain_opt,
MakeOptInt = yes
@@ -1352,186 +1290,6 @@ check_pragma_format_call(ProgressStream, ErrorStream, Verbose, Stats,
%---------------------------------------------------------------------------%
-maybe_simplify(ProgressStream, MaybeErrorStream, Warn, SimplifyPass,
- Verbose, Stats, !HLDS, !MaybeWrittenSpecs, !IO) :-
- module_info_get_globals(!.HLDS, Globals),
- some [!SimpList] (
- ( Warn = no, WarnGen = do_not_generate_warnings
- ; Warn = yes, WarnGen = generate_warnings
- ),
- find_simplify_tasks(Globals, WarnGen, SimplifyTasks0),
- !:SimpList = simplify_tasks_to_list(SimplifyTasks0),
- (
- SimplifyPass = simplify_pass_frontend,
- list.cons(simptask_after_front_end, !SimpList),
- list.cons(simptask_try_opt_const_structs, !SimpList),
- globals.lookup_accumulating_option(Globals, dump_hlds,
- DumpHLDSStages),
- (
- DumpHLDSStages = []
- ;
- DumpHLDSStages = [_ | _],
- % This makes HLDS dumps both smaller and more readable
- % (by reducing clutter).
- list.cons(simptask_delete_dead_vars, !SimpList)
- )
- ;
- SimplifyPass = simplify_pass_post_untuple,
- list.cons(simptask_mark_code_model_changes, !SimpList)
- ;
- SimplifyPass = simplify_pass_pre_prof_transforms,
-
- % We run the simplify pass before the profiling transformations
- % only if those transformations are being applied; otherwise we
- % just leave things to the backend simplification passes.
-
- globals.lookup_bool_option(Globals, pre_prof_transforms_simplify,
- PreProfSimplify),
- (
- PreProfSimplify = yes,
- list.cons(simptask_mark_code_model_changes, !SimpList)
- ;
- PreProfSimplify = no,
- !:SimpList = []
- )
- ;
- SimplifyPass = simplify_pass_pre_implicit_parallelism,
-
- % We run the simplify pass before the implicit parallelism pass if
- % implicit parallelism is enabled.
-
- globals.lookup_bool_option(Globals,
- pre_implicit_parallelism_simplify, PreParSimplify),
- (
- PreParSimplify = yes,
- list.cons(simptask_mark_code_model_changes, !SimpList)
- ;
- PreParSimplify = no,
- !:SimpList = []
- )
- ;
- SimplifyPass = simplify_pass_ml_backend,
- list.cons(simptask_mark_code_model_changes, !SimpList)
- ;
- SimplifyPass = simplify_pass_ll_backend,
- % Don't perform constant propagation if one of the
- % profiling transformations has been applied.
- %
- % NOTE: Any changes made here may also need to be made
- % to the relevant parts of backend_pass_by_preds_4/12.
- globals.get_opt_tuple(Globals, OptTuple),
- ConstProp = OptTuple ^ ot_prop_constants,
- globals.lookup_bool_option(Globals, profile_deep, DeepProf),
- globals.lookup_bool_option(Globals, record_term_sizes_as_words,
- TSWProf),
- globals.lookup_bool_option(Globals, record_term_sizes_as_cells,
- TSCProf),
- ( if
- ConstProp = prop_constants,
- DeepProf = no,
- TSWProf = no,
- TSCProf = no
- then
- list.cons(simptask_constant_prop, !SimpList)
- else
- list.delete_all(!.SimpList, simptask_constant_prop, !:SimpList)
- ),
- list.cons(simptask_mark_code_model_changes, !SimpList),
- list.cons(simptask_elim_removable_scopes, !SimpList)
- ),
- SimpList = !.SimpList
- ),
- (
- SimpList = [_ | _],
- (
- MaybeErrorStream = yes(ErrorStreamA),
- maybe_write_not_yet_written_specs(ErrorStreamA, Globals, Verbose,
- !MaybeWrittenSpecs, !IO)
- ;
- MaybeErrorStream = no
- ),
- maybe_write_string(ProgressStream, Verbose,
- "% Simplifying goals...\n", !IO),
- maybe_flush_output(ProgressStream, Verbose, !IO),
- SimplifyTasks = list_to_simplify_tasks(Globals, SimpList),
- process_valid_nonimported_preds_errors(
- update_pred_error(simplify_pred(ProgressStream, SimplifyTasks)),
- !HLDS, [], SimplifySpecs),
- (
- SimplifyPass = simplify_pass_frontend,
- (
- MaybeErrorStream = yes(ErrorStreamB),
- add_to_be_written_specs(SimplifySpecs, !MaybeWrittenSpecs),
- maybe_write_not_yet_written_specs(ErrorStreamB,
- Globals, Verbose, !MaybeWrittenSpecs, !IO)
- ;
- MaybeErrorStream = no,
- expect(unify(SimplifySpecs, []), $pred, "SimplifySpecs != []")
- )
- ;
- ( SimplifyPass = simplify_pass_ll_backend
- ; SimplifyPass = simplify_pass_ml_backend
- ; SimplifyPass = simplify_pass_post_untuple
- ; SimplifyPass = simplify_pass_pre_prof_transforms
- ; SimplifyPass = simplify_pass_pre_implicit_parallelism
- )
- ),
- maybe_write_string(ProgressStream, Verbose, "% done.\n", !IO),
- maybe_report_stats(ProgressStream, Stats, !IO)
- ;
- SimpList = []
- ).
-
-:- pred simplify_pred(io.text_output_stream::in,
- simplify_tasks::in, pred_id::in,
- module_info::in, module_info::out, pred_info::in, pred_info::out,
- list(diag_spec)::in, list(diag_spec)::out) is det.
-
-simplify_pred(ProgressStream, SimplifyTasks0, PredId,
- !ModuleInfo, !PredInfo, !Specs) :-
- trace [io(!IO)] (
- maybe_write_pred_progress_message(ProgressStream, !.ModuleInfo,
- "Simplifying", PredId, !IO)
- ),
- ProcIds = pred_info_will_codegen_proc_ids(!.PredInfo),
- % Don't warn for compiler-generated procedures.
- ( if is_unify_index_or_compare_pred(!.PredInfo) then
- SimplifyTasks = SimplifyTasks0 ^ do_warn_dodgy_simple_code
- := do_not_warn_dodgy_simple_code
- else
- SimplifyTasks = SimplifyTasks0
- ),
- PredSpecsAcc0 = init_diag_spec_accumulator,
- simplify_pred_procs(ProgressStream, SimplifyTasks, PredId, ProcIds,
- [], InputSpecDeletePPIds, !PredInfo, !ModuleInfo,
- PredSpecsAcc0, PredSpecsAcc),
- AfterFrontEnd = SimplifyTasks ^ do_after_front_end,
- (
- AfterFrontEnd = not_after_front_end
- ;
- AfterFrontEnd = after_front_end,
- list.foldl(delete_specified_proc, InputSpecDeletePPIds, !ModuleInfo)
- ),
- PredSpecs = diag_spec_accumulator_to_list(PredSpecsAcc),
- !:Specs = PredSpecs ++ !.Specs,
- module_info_get_globals(!.ModuleInfo, Globals),
- globals.lookup_bool_option(Globals, detailed_statistics, Statistics),
- trace [io(!IO)] (
- maybe_report_stats(ProgressStream, Statistics, !IO)
- ).
-
-:- pred delete_specified_proc(pred_proc_id::in,
- module_info::in, module_info::out) is det.
-
-delete_specified_proc(proc(PredId, ProcId), !ModuleInfo) :-
- module_info_pred_info(!.ModuleInfo, PredId, PredInfo0),
- pred_info_get_proc_table(PredInfo0, ProcTable0),
- map.delete(ProcId, ProcTable0, ProcTable),
- pred_info_set_proc_table(ProcTable, PredInfo0, PredInfo),
- module_info_set_pred_info(PredId, PredInfo, !ModuleInfo).
-
-%---------------------------------------------------------------------------%
-
:- pred maybe_generate_style_warnings(io.text_output_stream::in,
io.text_output_stream::in, bool::in, bool::in, module_info::in,
maybe_written_specs::in, maybe_written_specs::out, io::di, io::uo) is det.
diff --git a/compiler/mercury_compile_llds_back_end.m b/compiler/mercury_compile_llds_back_end.m
index bd5c9caf5..2ad45f1d2 100644
--- a/compiler/mercury_compile_llds_back_end.m
+++ b/compiler/mercury_compile_llds_back_end.m
@@ -108,7 +108,7 @@
:- import_module parse_tree.prog_data_foreign.
:- import_module parse_tree.prog_foreign.
:- import_module parse_tree.write_error_spec.
-:- import_module top_level.mercury_compile_front_end.
+:- import_module top_level.mercury_compile_simplify.
:- import_module assoc_list.
:- import_module cord.
diff --git a/compiler/mercury_compile_main.m b/compiler/mercury_compile_main.m
index e49199bb7..3a59a2690 100644
--- a/compiler/mercury_compile_main.m
+++ b/compiler/mercury_compile_main.m
@@ -797,6 +797,9 @@ do_process_compiler_arg(ProgressStream, ErrorStream, Globals0,
!HaveParseTreeMaps, !MaybeWrittenSpecs, !IO) :-
% XXX ITEM_LIST There is an inconsistency between the various OpModeArgs
% that construct a module_and_imports structure in how they do it.
+ % (XXX The module_and_imports structure has been replaced by other
+ % structures, including aug_compilation_units, since this comment
+ % was written.)
%
% The op modes that generate one or more dependency files call predicates
% in d_file_deps.m, which all end up constructing that structure
diff --git a/compiler/mercury_compile_middle_passes.m b/compiler/mercury_compile_middle_passes.m
index 6c1ff8a74..20e2bf823 100644
--- a/compiler/mercury_compile_middle_passes.m
+++ b/compiler/mercury_compile_middle_passes.m
@@ -77,7 +77,7 @@
:- import_module termination.term_constr.term_constr_main.
:- import_module termination.term_osi.
:- import_module termination.term_osi.term_osi_main.
-:- import_module top_level.mercury_compile_front_end.
+:- import_module top_level.mercury_compile_simplify.
:- import_module transform_hlds.
:- import_module transform_hlds.accumulator.
:- import_module transform_hlds.closure_analysis.
diff --git a/compiler/mercury_compile_mlds_back_end.m b/compiler/mercury_compile_mlds_back_end.m
index ecd029cfc..f44b94397 100644
--- a/compiler/mercury_compile_mlds_back_end.m
+++ b/compiler/mercury_compile_mlds_back_end.m
@@ -74,8 +74,8 @@
:- import_module ml_backend.rtti_to_mlds. % HLDS/RTTI -> MLDS
:- import_module parse_tree.error_spec.
:- import_module parse_tree.file_names.
-:- import_module top_level.mercury_compile_front_end.
:- import_module top_level.mercury_compile_llds_back_end.
+:- import_module top_level.mercury_compile_simplify.
:- import_module bool.
:- import_module list.
diff --git a/compiler/mercury_compile_simplify.m b/compiler/mercury_compile_simplify.m
new file mode 100644
index 000000000..2b266f68b
--- /dev/null
+++ b/compiler/mercury_compile_simplify.m
@@ -0,0 +1,283 @@
+%---------------------------------------------------------------------------%
+% vim: ft=mercury ts=4 sw=4 et
+%---------------------------------------------------------------------------%
+% Copyright (C) 1994-2011 The University of Melbourne.
+% Copyright (C) 2014-2026 The Mercury team.
+% This file may only be copied under the terms of the GNU General
+% Public License - see the file COPYING in the Mercury distribution.
+%---------------------------------------------------------------------------%
+%
+% File: mercury_compile_simplify.m.
+%
+% This module implements the interface between compiler's top level
+% (mainly the front-end, but also the back-end) and the simplification pass.
+%
+%---------------------------------------------------------------------------%
+
+:- module top_level.mercury_compile_simplify.
+:- interface.
+
+:- import_module hlds.
+:- import_module hlds.hlds_module.
+:- import_module parse_tree.
+:- import_module parse_tree.error_util.
+
+:- import_module bool.
+:- import_module io.
+:- import_module maybe.
+
+%---------------------------------------------------------------------------%
+
+ % This type indicates what stage of compilation we are running
+ % the simplification pass at. The exact simplifications tasks we run
+ % will depend upon this.
+ %
+:- type simplify_pass
+ ---> simplify_pass_frontend
+ % Running simplification immediately after all the semantic
+ % analysis passes in the frontend. As of 2025 sep 13,
+ % this is stage 65.
+
+ ; simplify_pass_post_untuple
+ % Running simplification after the untupling transformation
+ % has been applied. As of 2025 sep 13, this is stage 133.
+
+ ; simplify_pass_pre_implicit_parallelism
+ % Running simplification before the implicit parallelism
+ % transformation, if it is enabled. This helps ensure that
+ % the HLDS matches the feedback data. As of 2025 sep 13,
+ % this is stage 172.
+
+ ; simplify_pass_pre_prof_transforms
+ % Running simplification before either the term size profiling
+ % or the profiling transformation, if either is enabled.
+ % The reason for this pass is mainly to make up for the fact
+ % that some simplifications that we can do using standard code
+ % before these transforms would require more complex analysis,
+ % if they were possible at all, after these transforms,
+ % due to their introduction of e.g. impure code into the HLDS.
+ % As of 2025 sep 13, this is stage 215.
+
+ ; simplify_pass_ll_backend
+ % One of the passes of the LLDS backend. As of 2025 sep 13,
+ % this is stage 325.
+
+ ; simplify_pass_ml_backend.
+ % The first pass of the MLDS backend. As of 2025 sep 13,
+ % this is stage 405.
+
+ % This predicate sets up and maybe runs the simplification pass.
+ %
+:- pred maybe_simplify(io.text_output_stream::in,
+ maybe(io.text_output_stream)::in, bool::in, simplify_pass::in,
+ bool::in, bool::in, module_info::in, module_info::out,
+ maybe_written_specs::in, maybe_written_specs::out, io::di, io::uo) is det.
+
+%---------------------------------------------------------------------------%
+%---------------------------------------------------------------------------%
+
+:- implementation.
+
+:- import_module check_hlds.
+:- import_module check_hlds.simplify.
+:- import_module check_hlds.simplify.simplify_proc.
+:- import_module check_hlds.simplify.simplify_tasks.
+:- import_module hlds.hlds_pred.
+:- import_module hlds.hlds_pred_tests.
+:- import_module hlds.passes_aux.
+:- import_module hlds.pred_proc_id.
+:- import_module libs.
+:- import_module libs.file_util.
+:- import_module libs.globals.
+:- import_module libs.optimization_options.
+:- import_module libs.options.
+:- import_module parse_tree.error_spec.
+:- import_module parse_tree.write_error_spec.
+
+:- import_module list.
+:- import_module map.
+:- import_module require.
+
+%---------------------------------------------------------------------------%
+
+maybe_simplify(ProgressStream, MaybeErrorStream, Warn, SimplifyPass,
+ Verbose, Stats, !HLDS, !MaybeWrittenSpecs, !IO) :-
+ module_info_get_globals(!.HLDS, Globals),
+ some [!SimpList] (
+ ( Warn = no, WarnGen = do_not_generate_warnings
+ ; Warn = yes, WarnGen = generate_warnings
+ ),
+ find_simplify_tasks(Globals, WarnGen, SimplifyTasks0),
+ !:SimpList = simplify_tasks_to_list(SimplifyTasks0),
+ (
+ SimplifyPass = simplify_pass_frontend,
+ list.cons(simptask_after_front_end, !SimpList),
+ list.cons(simptask_try_opt_const_structs, !SimpList),
+ globals.lookup_accumulating_option(Globals, dump_hlds,
+ DumpHLDSStages),
+ (
+ DumpHLDSStages = []
+ ;
+ DumpHLDSStages = [_ | _],
+ % This makes HLDS dumps both smaller and more readable
+ % (by reducing clutter).
+ list.cons(simptask_delete_dead_vars, !SimpList)
+ )
+ ;
+ SimplifyPass = simplify_pass_post_untuple,
+ list.cons(simptask_mark_code_model_changes, !SimpList)
+ ;
+ SimplifyPass = simplify_pass_pre_prof_transforms,
+
+ % We run the simplify pass before the profiling transformations
+ % only if those transformations are being applied; otherwise we
+ % just leave things to the backend simplification passes.
+
+ globals.lookup_bool_option(Globals, pre_prof_transforms_simplify,
+ PreProfSimplify),
+ (
+ PreProfSimplify = yes,
+ list.cons(simptask_mark_code_model_changes, !SimpList)
+ ;
+ PreProfSimplify = no,
+ !:SimpList = []
+ )
+ ;
+ SimplifyPass = simplify_pass_pre_implicit_parallelism,
+
+ % We run the simplify pass before the implicit parallelism pass if
+ % implicit parallelism is enabled.
+
+ globals.lookup_bool_option(Globals,
+ pre_implicit_parallelism_simplify, PreParSimplify),
+ (
+ PreParSimplify = yes,
+ list.cons(simptask_mark_code_model_changes, !SimpList)
+ ;
+ PreParSimplify = no,
+ !:SimpList = []
+ )
+ ;
+ SimplifyPass = simplify_pass_ml_backend,
+ list.cons(simptask_mark_code_model_changes, !SimpList)
+ ;
+ SimplifyPass = simplify_pass_ll_backend,
+ % Don't perform constant propagation if one of the
+ % profiling transformations has been applied.
+ %
+ % NOTE: Any changes made here may also need to be made
+ % to the relevant parts of backend_pass_by_preds_4/12.
+ globals.get_opt_tuple(Globals, OptTuple),
+ ConstProp = OptTuple ^ ot_prop_constants,
+ globals.lookup_bool_option(Globals, profile_deep, DeepProf),
+ globals.lookup_bool_option(Globals, record_term_sizes_as_words,
+ TSWProf),
+ globals.lookup_bool_option(Globals, record_term_sizes_as_cells,
+ TSCProf),
+ ( if
+ ConstProp = prop_constants,
+ DeepProf = no,
+ TSWProf = no,
+ TSCProf = no
+ then
+ list.cons(simptask_constant_prop, !SimpList)
+ else
+ list.delete_all(!.SimpList, simptask_constant_prop, !:SimpList)
+ ),
+ list.cons(simptask_mark_code_model_changes, !SimpList),
+ list.cons(simptask_elim_removable_scopes, !SimpList)
+ ),
+ SimpList = !.SimpList
+ ),
+ (
+ SimpList = [_ | _],
+ (
+ MaybeErrorStream = yes(ErrorStreamA),
+ maybe_write_not_yet_written_specs(ErrorStreamA, Globals, Verbose,
+ !MaybeWrittenSpecs, !IO)
+ ;
+ MaybeErrorStream = no
+ ),
+ maybe_write_string(ProgressStream, Verbose,
+ "% Simplifying goals...\n", !IO),
+ maybe_flush_output(ProgressStream, Verbose, !IO),
+ SimplifyTasks = list_to_simplify_tasks(Globals, SimpList),
+ process_valid_nonimported_preds_errors(
+ update_pred_error(simplify_pred(ProgressStream, SimplifyTasks)),
+ !HLDS, [], SimplifySpecs),
+ (
+ SimplifyPass = simplify_pass_frontend,
+ (
+ MaybeErrorStream = yes(ErrorStreamB),
+ add_to_be_written_specs(SimplifySpecs, !MaybeWrittenSpecs),
+ maybe_write_not_yet_written_specs(ErrorStreamB,
+ Globals, Verbose, !MaybeWrittenSpecs, !IO)
+ ;
+ MaybeErrorStream = no,
+ expect(unify(SimplifySpecs, []), $pred, "SimplifySpecs != []")
+ )
+ ;
+ ( SimplifyPass = simplify_pass_ll_backend
+ ; SimplifyPass = simplify_pass_ml_backend
+ ; SimplifyPass = simplify_pass_post_untuple
+ ; SimplifyPass = simplify_pass_pre_prof_transforms
+ ; SimplifyPass = simplify_pass_pre_implicit_parallelism
+ )
+ ),
+ maybe_write_string(ProgressStream, Verbose, "% done.\n", !IO),
+ maybe_report_stats(ProgressStream, Stats, !IO)
+ ;
+ SimpList = []
+ ).
+
+:- pred simplify_pred(io.text_output_stream::in,
+ simplify_tasks::in, pred_id::in,
+ module_info::in, module_info::out, pred_info::in, pred_info::out,
+ list(diag_spec)::in, list(diag_spec)::out) is det.
+
+simplify_pred(ProgressStream, SimplifyTasks0, PredId,
+ !ModuleInfo, !PredInfo, !Specs) :-
+ trace [io(!IO)] (
+ maybe_write_pred_progress_message(ProgressStream, !.ModuleInfo,
+ "Simplifying", PredId, !IO)
+ ),
+ ProcIds = pred_info_will_codegen_proc_ids(!.PredInfo),
+ % Don't warn for compiler-generated procedures.
+ ( if is_unify_index_or_compare_pred(!.PredInfo) then
+ SimplifyTasks = SimplifyTasks0 ^ do_warn_dodgy_simple_code
+ := do_not_warn_dodgy_simple_code
+ else
+ SimplifyTasks = SimplifyTasks0
+ ),
+ PredSpecsAcc0 = init_diag_spec_accumulator,
+ simplify_pred_procs(ProgressStream, SimplifyTasks, PredId, ProcIds,
+ [], InputSpecDeletePPIds, !PredInfo, !ModuleInfo,
+ PredSpecsAcc0, PredSpecsAcc),
+ AfterFrontEnd = SimplifyTasks ^ do_after_front_end,
+ (
+ AfterFrontEnd = not_after_front_end
+ ;
+ AfterFrontEnd = after_front_end,
+ list.foldl(delete_specified_proc, InputSpecDeletePPIds, !ModuleInfo)
+ ),
+ PredSpecs = diag_spec_accumulator_to_list(PredSpecsAcc),
+ !:Specs = PredSpecs ++ !.Specs,
+ module_info_get_globals(!.ModuleInfo, Globals),
+ globals.lookup_bool_option(Globals, detailed_statistics, Statistics),
+ trace [io(!IO)] (
+ maybe_report_stats(ProgressStream, Statistics, !IO)
+ ).
+
+:- pred delete_specified_proc(pred_proc_id::in,
+ module_info::in, module_info::out) is det.
+
+delete_specified_proc(proc(PredId, ProcId), !ModuleInfo) :-
+ module_info_pred_info(!.ModuleInfo, PredId, PredInfo0),
+ pred_info_get_proc_table(PredInfo0, ProcTable0),
+ map.delete(ProcId, ProcTable0, ProcTable),
+ pred_info_set_proc_table(ProcTable, PredInfo0, PredInfo),
+ module_info_set_pred_info(PredId, PredInfo, !ModuleInfo).
+
+%---------------------------------------------------------------------------%
+:- end_module top_level.mercury_compile_simplify.
+%---------------------------------------------------------------------------%
diff --git a/compiler/notes/compiler_design.html b/compiler/notes/compiler_design.html
index 21b281fad..a2961bcab 100644
--- a/compiler/notes/compiler_design.html
+++ b/compiler/notes/compiler_design.html
@@ -83,7 +83,9 @@ Step 1, the conversion of parse trees to the initial version of the HLDS,
is managed by mercury_compile_make_hlds.m.
Step 2, semantic analysis of the HLDS,
-is managed by mercury_compile_front_end.m.
+is managed by mercury_compile_front_end.m,
+with mercury_compile_simplify.m having control of simplification
+(which is also needed by the middle end and by the backends).
Step 3, the suite of high level transformations on the HLDS,
is managed by mercury_compile_middle_passes.m.
diff --git a/compiler/top_level.m b/compiler/top_level.m
index e4b8b439d..0ae34b671 100644
--- a/compiler/top_level.m
+++ b/compiler/top_level.m
@@ -22,6 +22,7 @@
:- include_module mercury_compile_augment.
:- include_module mercury_compile_make_hlds.
:- include_module mercury_compile_front_end.
+:- include_module mercury_compile_simplify.
:- include_module mercury_compile_middle_passes.
:- include_module mercury_compile_llds_back_end.
:- include_module mercury_compile_mlds_back_end.