for review: deforestation [2/4]
Simon Taylor
stayl at cs.mu.OZ.AU
Thu Feb 19 16:37:40 AEDT 1998
Index: compiler/simplify.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/simplify.m,v
retrieving revision 1.54
diff -u -r1.54 simplify.m
--- simplify.m 1998/02/14 14:41:04 1.54
+++ simplify.m 1998/02/18 04:49:26
@@ -16,7 +16,7 @@
% they should not have been included in the program in the first place.
%
% Simplification is done in two passes. The first pass performs common
-% structure elimination and branch merging. The second pass performs
+% structure and duplicate call elimination. The second pass performs
% excess assignment elimination and cleans up the code after the first pass.
% Two passes are required because the goal must be requantified after the
% optimizations in common.m are run so that excess assignment elimination
@@ -35,135 +35,165 @@
proc_info, proc_info, int, int, io__state, io__state).
:- mode simplify__proc(in, in, in, in, out, in, out, out, out, di, uo) is det.
-:- pred simplify__goal(hlds_goal, hlds_goal,
+:- pred simplify__process_goal(hlds_goal, hlds_goal,
simplify_info, simplify_info).
-:- mode simplify__goal(in, out, in, out) is det.
-
-:- pred simplify_info_init(det_info, simplify, instmap,
- varset, map(var, type), simplify_info).
-:- mode simplify_info_init(in, in, in, in, in, out) is det.
+:- mode simplify__process_goal(in, out, in, out) is det.
:- type simplify_info.
+ % XXX Since this is now called from several places, rework this
+ % interface to avoid the booleans.
:- type simplify
---> simplify(
bool, % --warn-simple-code
bool, % --warn-duplicate-calls
bool, % run things that should be done once only
- bool, % attempt to merge adjacent switches
bool, % common subexpression elimination
bool, % remove excess assignment unifications
bool, % optimize duplicate calls
- bool % partially evaluate calls
+ bool, % partially evaluate calls
+ bool % do common structure elimination even
+ % when it might increase stack usage (used
+ % by deforestation).
).
%-----------------------------------------------------------------------------%
:- implementation.
-:- import_module hlds_out.
-
:- import_module code_aux, det_analysis, follow_code, goal_util, const_prop.
:- import_module hlds_module, hlds_goal, hlds_data, (inst), inst_match.
:- import_module globals, options, passes_aux, prog_data, mode_util, type_util.
-:- import_module code_util, quantification, modes, purity.
+:- import_module code_util, quantification, modes, purity, pd_cost.
:- import_module bool, list, set, map, require, std_util, term, varset, int.
%-----------------------------------------------------------------------------%
simplify__proc(Simplify, PredId, ProcId, ModuleInfo0, ModuleInfo,
- Proc0, Proc, WarnCnt, ErrCnt, State0, State) :-
+ Proc0, Proc, WarnCnt, ErrCnt) -->
+ write_pred_progress_message("% Simplifying ", PredId, ModuleInfo0),
+ simplify__proc_2(Simplify, PredId, ProcId, ModuleInfo0,
+ ModuleInfo, Proc0, Proc, WarnCnt, ErrCnt).
+
+:- pred simplify__proc_2(simplify, pred_id, proc_id, module_info,
+ module_info, proc_info, proc_info, int, int,
+ io__state, io__state).
+:- mode simplify__proc_2(in, in, in, in, out, in, out,
+ out, out, di, uo) is det.
+
+simplify__proc_2(Simplify0, PredId, ProcId, ModuleInfo0, ModuleInfo,
+ ProcInfo0, ProcInfo, WarnCnt, ErrCnt, State0, State) :-
+ Simplify0 = simplify(Warn0, WarnCalls, Once, Common,
+ Excess, Calls, Prop, MoreCommon),
+ (
+ % Don't warn for compiler-generated procedures.
+ Warn0 = yes,
+ module_info_pred_info(ModuleInfo0, PredId, PredInfo),
+ code_util__compiler_generated(PredInfo)
+ ->
+ Warn = no
+ ;
+ Warn = Warn0
+ ),
+ Simplify = simplify(Warn, WarnCalls, Once, Common,
+ Excess, Calls, Prop, MoreCommon),
+
globals__io_get_globals(Globals, State0, State1),
det_info_init(ModuleInfo0, PredId, ProcId, Globals, DetInfo0),
- proc_info_get_initial_instmap(Proc0, ModuleInfo0, InstMap0),
- proc_info_varset(Proc0, VarSet0),
- proc_info_vartypes(Proc0, VarTypes0),
+ proc_info_get_initial_instmap(ProcInfo0, ModuleInfo0, InstMap0),
+ proc_info_varset(ProcInfo0, VarSet0),
+ proc_info_vartypes(ProcInfo0, VarTypes0),
+ proc_info_goal(ProcInfo0, Goal0),
+
simplify_info_init(DetInfo0, Simplify, InstMap0,
VarSet0, VarTypes0, Info0),
- write_pred_progress_message("% Simplifying ", PredId, ModuleInfo0,
- State1, State2),
- Simplify = simplify(Warn, WarnCalls, Once, Switch, _,
- Excess, Calls, Prop),
- ( simplify_do_common(Info0) ->
- % On the first pass do common structure elimination and
- % branch merging.
- simplify_info_set_simplify(Info0,
- simplify(Warn, WarnCalls, no, Switch, yes, no,
- Calls, Prop), Info1),
- simplify__proc_2(Proc0, Proc1, Info1, Info2, State2, State3),
- simplify_info_get_msgs(Info2, Msgs1),
- simplify_info_get_det_info(Info2, DetInfo1),
- proc_info_varset(Proc1, VarSet1),
- proc_info_vartypes(Proc1, VarTypes1),
- simplify_info_init(DetInfo1,
- simplify(no, no, Once, no, no, Excess, no, Prop),
- InstMap0, VarSet1, VarTypes1, Info3),
- simplify_info_set_msgs(Info3, Msgs1, Info4),
- %simplify_info_get_module_info(Info4, ModuleInfo1),
- %proc_info_goal(Proc1, OutGoal),
- %hlds_out__write_goal(OutGoal, ModuleInfo1, VarSet1, yes,
- % 2, ".", State3, State4)
- State4 = State3
- ;
- Info4 = Info0,
- Proc1 = Proc0,
- State4 = State2
- ),
- % On the second pass do excess assignment elimination and
- % some cleaning up after the common structure and branch
- % merging pass.
- simplify__proc_2(Proc1, Proc, Info4, Info, State4, State5),
+ simplify__process_goal(Goal0, Goal, Info0, Info),
+
simplify_info_get_module_info(Info, ModuleInfo),
- simplify_info_get_msgs(Info, Msgs2),
- set__to_sorted_list(Msgs2, Msgs),
+ simplify_info_get_msgs(Info, Msgs0),
+ set__to_sorted_list(Msgs0, Msgs),
( (Warn = yes ; WarnCalls = yes) ->
det_report_msgs(Msgs, ModuleInfo, WarnCnt,
- ErrCnt, State5, State)
+ ErrCnt, State1, State)
;
WarnCnt = 0,
ErrCnt = 0,
- State = State5
- ).
+ State = State1
+ ),
+ simplify_info_get_varset(Info, VarSet),
+ simplify_info_get_var_types(Info, VarTypes),
+ proc_info_set_varset(ProcInfo0, VarSet, ProcInfo1),
+ proc_info_set_vartypes(ProcInfo1, VarTypes, ProcInfo2),
+ proc_info_set_goal(ProcInfo2, Goal, ProcInfo).
+
+simplify__process_goal(Goal0, Goal, Info0, Info) :-
+ simplify_info_get_simplify(Info0, Simplify0),
+ simplify_info_get_instmap(Info0, InstMap0),
+ Simplify0 = simplify(Warn, WarnCalls, Once, Common,
+ Excess, Calls, Prop, MoreCommon),
-:- pred simplify__proc_2(proc_info::in, proc_info::out,
- simplify_info::in, simplify_info::out,
- io__state::di, io__state::uo) is det.
-
-simplify__proc_2(Proc0, Proc, Info0, Info, State0, State) :-
- proc_info_goal(Proc0, Goal0),
- simplify__goal(Goal0, Goal, Info0, Info1),
- simplify_info_get_varset(Info1, VarSet),
- simplify_info_get_var_types(Info1, VarTypes),
- proc_info_set_goal(Proc0, Goal, Proc1),
- proc_info_set_varset(Proc1, VarSet, Proc2),
- proc_info_set_vartypes(Proc2, VarTypes, Proc3),
+ ( Common = yes ->
+ % On the first pass do common structure elimination and
+ % branch merging.
+ simplify_info_set_simplify(Info0,
+ simplify(Warn, WarnCalls, no, Common, no,
+ Calls, Prop, MoreCommon),
+ Info1),
+
+ simplify__do_process_goal(Goal0, Goal1, Info1, Info2),
+
+ simplify_info_reinit(
+ simplify(no, no, Once, no, Excess, no, Prop, no),
+ InstMap0, Info2, Info3)
+ ;
+ Info3 = Info0,
+ Goal1 = Goal0
+ ),
+ % On the second pass do excess assignment elimination and
+ % some cleaning up after the common structure pass.
+ simplify__do_process_goal(Goal1, Goal, Info3, Info).
+
+:- pred simplify__do_process_goal(hlds_goal::in, hlds_goal::out,
+ simplify_info::in, simplify_info::out) is det.
+
+simplify__do_process_goal(Goal0, Goal, Info0, Info) :-
+ simplify_info_get_instmap(Info0, InstMap0),
+ simplify__goal(Goal0, Goal1, Info0, Info1),
+ simplify_info_get_varset(Info1, VarSet0),
+ simplify_info_get_var_types(Info1, VarTypes0),
( simplify_info_requantify(Info1) ->
- requantify_proc(Proc3, Proc4),
- ( simplify_info_recompute_atomic(Info1) ->
+ Goal1 = _ - GoalInfo1,
+ goal_info_get_nonlocals(GoalInfo1, NonLocals),
+
+ implicitly_quantify_goal(Goal1, VarSet0, VarTypes0, NonLocals,
+ Goal2, VarSet, VarTypes, _),
+
+ simplify_info_set_varset(Info1, VarSet, Info2),
+ simplify_info_set_var_types(Info2, VarTypes, Info3),
+ ( simplify_info_recompute_atomic(Info3) ->
RecomputeAtomic = yes
;
RecomputeAtomic = no
),
- proc_info_goal(Proc4, Goal2),
- simplify_info_get_module_info(Info1, ModuleInfo1),
- proc_info_get_initial_instmap(Proc4, ModuleInfo1, InstMap0),
- recompute_instmap_delta(RecomputeAtomic, Goal2, Goal3,
+
+ simplify_info_get_module_info(Info3, ModuleInfo1),
+ recompute_instmap_delta(RecomputeAtomic, Goal2, Goal,
InstMap0, ModuleInfo1, ModuleInfo),
- simplify_info_set_module_info(Info1, ModuleInfo, Info),
- proc_info_set_goal(Proc4, Goal3, Proc),
- State = State0
+ simplify_info_set_module_info(Info3, ModuleInfo, Info)
;
- Proc = Proc3,
- State = State0,
+ Goal = Goal1,
Info = Info1
).
%-----------------------------------------------------------------------------%
+:- pred simplify__goal(hlds_goal, hlds_goal, simplify_info, simplify_info).
+:- mode simplify__goal(in, out, in, out) is det.
+
simplify__goal(Goal0, Goal - GoalInfo, Info0, Info) :-
- Goal0 = _GoalExpr0 - GoalInfo0,
- simplify_info_get_det_info(Info0, DetInfo),
+ Goal0 = _ - GoalInfo0,
goal_info_get_determinism(GoalInfo0, Detism),
+ simplify_info_get_det_info(Info0, DetInfo),
simplify_info_get_module_info(Info0, ModuleInfo),
(
%
@@ -178,6 +208,8 @@
; code_aux__goal_cannot_loop(ModuleInfo, Goal0)
)
->
+ pd_cost__goal(Goal0, CostDelta),
+ simplify_info_incr_cost_delta(Info0, CostDelta, Info1),
fail_goal(Goal1)
;
%
@@ -203,14 +235,17 @@
; code_aux__goal_cannot_loop(ModuleInfo, Goal0)
)
->
+ pd_cost__goal(Goal0, CostDelta),
+ simplify_info_incr_cost_delta(Info0, CostDelta, Info1),
true_goal(Goal1)
;
- Goal1 = Goal0
+ Goal1 = Goal0,
+ Info1 = Info0
),
- simplify_info_maybe_clear_structs(before, Goal1, Info0, Info1),
+ simplify_info_maybe_clear_structs(before, Goal1, Info1, Info2),
Goal1 = GoalExpr1 - GoalInfo1,
- simplify__goal_2(GoalExpr1, GoalInfo1, Goal, GoalInfo2, Info1, Info2),
- simplify_info_maybe_clear_structs(after, Goal - GoalInfo2, Info2, Info),
+ simplify__goal_2(GoalExpr1, GoalInfo1, Goal, GoalInfo2, Info2, Info3),
+ simplify_info_maybe_clear_structs(after, Goal - GoalInfo2, Info3, Info),
simplify__enforce_invariant(GoalInfo2, GoalInfo).
@@ -248,11 +283,9 @@
:- mode simplify__goal_2(in, in, out, out, in, out) is det.
simplify__goal_2(conj(Goals0), GoalInfo0, Goal, GoalInfo0, Info0, Info) :-
- simplify_info_reset_branch_info(Info0, Info1, PostBranchInstMaps),
- simplify_info_get_instmap(Info1, InstMap0),
- simplify__conj(Goals0, [], Goals, GoalInfo0, Info1, Info2),
- simplify_info_set_branch_info(Info2, PostBranchInstMaps, Info3),
- simplify_info_set_instmap(Info3, InstMap0, Info),
+ simplify_info_get_instmap(Info0, InstMap0),
+ simplify__conj(Goals0, [], Goals, GoalInfo0, Info0, Info1),
+ simplify_info_set_instmap(Info1, InstMap0, Info),
( Goals = [SingleGoal] ->
% a singleton conjunction is equivalent to the goal itself
SingleGoal = Goal - _
@@ -308,9 +341,8 @@
)
;
simplify_info_get_instmap(Info0, InstMap0),
- simplify__disj(Disjuncts0, Disjuncts, [], InstMaps,
+ simplify__disj(Disjuncts0, [], Disjuncts, [], InstMaps,
Info0, Info0, Info1),
- simplify_info_create_branch_info(Info0, Info1, InstMaps, Info2),
(
/****
XXX This optimization is not correct, see comment below
@@ -335,17 +367,25 @@
;
****/
Goal = disj(Disjuncts, SM),
- simplify_info_get_module_info(Info2, ModuleInfo1),
- goal_info_get_nonlocals(GoalInfo0, NonLocals),
- merge_instmap_deltas(InstMap0, NonLocals, InstMaps,
- NewDelta, ModuleInfo1, ModuleInfo2),
- simplify_info_set_module_info(Info2, ModuleInfo2, Info),
- goal_info_set_instmap_delta(GoalInfo0, NewDelta,
- GoalInfo)
+ ( Disjuncts = [] ->
+ GoalInfo = GoalInfo0,
+ Info = Info1
+ ;
+ simplify_info_get_module_info(Info1,
+ ModuleInfo1),
+ goal_info_get_nonlocals(GoalInfo0, NonLocals),
+ merge_instmap_deltas(InstMap0, NonLocals,
+ InstMaps, NewDelta,
+ ModuleInfo1, ModuleInfo2),
+ simplify_info_set_module_info(Info1,
+ ModuleInfo2, Info),
+ goal_info_set_instmap_delta(GoalInfo0,
+ NewDelta, GoalInfo)
+ )
)
).
-simplify__goal_2(switch(Var, SwitchCanFail, Cases0, SM),
+simplify__goal_2(switch(Var, SwitchCanFail0, Cases0, SM),
GoalInfo0, Goal, GoalInfo, Info0, Info) :-
simplify_info_get_instmap(Info0, InstMap0),
simplify_info_get_module_info(Info0, ModuleInfo0),
@@ -359,11 +399,14 @@
Cases1 = Cases0,
MaybeConsIds = no
),
- ( Cases1 = [] ->
+ simplify__switch(Var, Cases1, [], Cases, [], InstMaps,
+ SwitchCanFail0, SwitchCanFail, Info0, Info0, Info1),
+ ( Cases = [] ->
% An empty switch always fails.
- fail_goal(Goal - GoalInfo),
- Info = Info0
- ; Cases1 = [case(ConsId, SingleGoal0)] ->
+ pd_cost__eliminate_switch(CostDelta),
+ simplify_info_incr_cost_delta(Info1, CostDelta, Info),
+ fail_goal(Goal - GoalInfo)
+ ; Cases = [case(ConsId, SingleGoal)] ->
% a singleton switch is equivalent to the goal itself with
% a possibly can_fail unification with the functor on the front.
cons_id_arity(ConsId, Arity),
@@ -372,40 +415,46 @@
MaybeConsIds \= yes([ConsId])
->
simplify__create_test_unification(Var, ConsId, Arity,
- UnifyGoal, Info0, Info1),
+ UnifyGoal, Info1, Info2),
% Conjoin the test and the rest of the case.
- goal_to_conj_list(SingleGoal0, SingleGoalConj),
+ goal_to_conj_list(SingleGoal, SingleGoalConj),
GoalList = [UnifyGoal | SingleGoalConj],
- % Work out the nonlocals, instmap_delta and determinism
- % of the entire conjunction, starting with an empty
- % goal_info.
- set__init(NonLocals),
- instmap_delta_init_reachable(InstMapDelta),
- goal_info_init(NonLocals, InstMapDelta, det,
- CombinedGoalInfo0),
- simplify__approximate_goal_info(GoalList,
- CombinedGoalInfo0, CombinedGoalInfo),
- simplify_info_set_requantify(Info1, Info2),
- Goal1 = conj(GoalList) - CombinedGoalInfo
+ % Work out the nonlocals, instmap_delta
+ % and determinism of the entire conjunction.
+ goal_info_get_nonlocals(GoalInfo0, NonLocals0),
+ set__insert(NonLocals0, Var, NonLocals),
+ goal_info_get_instmap_delta(GoalInfo0, InstMapDelta0),
+ simplify_info_get_instmap(Info2, InstMap),
+ instmap_delta_bind_var_to_functor(Var, ConsId,
+ InstMap, InstMapDelta0, InstMapDelta,
+ ModuleInfo0, ModuleInfo),
+ simplify_info_set_module_info(Info2,
+ ModuleInfo, Info3),
+ goal_info_get_determinism(GoalInfo0, CaseDetism),
+ det_conjunction_detism(semidet, CaseDetism, Detism),
+ goal_info_init(NonLocals, InstMapDelta, Detism,
+ CombinedGoalInfo),
+
+ simplify_info_set_requantify(Info3, Info4),
+ Goal = conj(GoalList),
+ GoalInfo = CombinedGoalInfo
;
% The var can only be bound to this cons_id, so
% a test is unnecessary.
- Goal1 = SingleGoal0,
- Info2 = Info0
+ SingleGoal = Goal - GoalInfo,
+ Info4 = Info1
),
- simplify__goal(Goal1, Goal - GoalInfo, Info2, Info)
+ pd_cost__eliminate_switch(CostDelta),
+ simplify_info_incr_cost_delta(Info4, CostDelta, Info)
;
- simplify__switch(Var, Cases1, Cases, [], InstMaps,
- Info0, Info0, Info1),
- simplify_info_create_branch_info(Info0, Info1, InstMaps, Info2),
Goal = switch(Var, SwitchCanFail, Cases, SM),
- simplify_info_get_module_info(Info2, ModuleInfo1),
+ simplify_info_get_module_info(Info1, ModuleInfo1),
goal_info_get_nonlocals(GoalInfo0, NonLocals),
merge_instmap_deltas(InstMap0, NonLocals, InstMaps, NewDelta,
ModuleInfo1, ModuleInfo2),
- simplify_info_set_module_info(Info2, ModuleInfo2, Info),
+ simplify_info_set_module_info(Info1, ModuleInfo2, Info),
goal_info_set_instmap_delta(GoalInfo0, NewDelta, GoalInfo)
).
@@ -703,14 +752,12 @@
CondThenDelta),
Else = _ - ElseInfo,
goal_info_get_instmap_delta(ElseInfo, ElseDelta),
- simplify_info_create_branch_info(Info0, Info6,
- [ElseDelta, CondThenDelta], Info7),
goal_info_get_nonlocals(GoalInfo0, NonLocals),
- simplify_info_get_module_info(Info7, ModuleInfo0),
+ simplify_info_get_module_info(Info6, ModuleInfo0),
merge_instmap_deltas(InstMap0, NonLocals,
[CondThenDelta, ElseDelta], NewDelta,
ModuleInfo0, ModuleInfo1),
- simplify_info_set_module_info(Info7, ModuleInfo1, Info),
+ simplify_info_set_module_info(Info6, ModuleInfo1, Info),
goal_info_set_instmap_delta(GoalInfo0, NewDelta, GoalInfo1),
IfThenElse = if_then_else(Vars, Cond, Then, Else, SM),
%
@@ -852,29 +899,18 @@
list__append(SubGoals, Goals0, Goals1),
simplify__conj(Goals1, RevGoals0, Goals, ConjInfo, Info0, Info)
;
- simplify_info_reset_branch_info(Info0, Info1, BranchInstMaps),
- simplify__goal(Goal0, Goal1, Info1, Info2),
+ simplify__goal(Goal0, Goal1, Info0, Info1),
(
% Flatten conjunctions.
Goal1 = conj(SubGoals1) - _
->
- simplify_info_undo_goal_updates(Info1, Info2, Info3),
- simplify_info_set_branch_info(Info3, BranchInstMaps, Info4),
+ simplify_info_undo_goal_updates(Info0, Info1, Info2),
list__append(SubGoals1, Goals0, Goals1),
- simplify__conj(Goals1, RevGoals0, Goals, ConjInfo, Info4, Info)
- ;
- % Merge branching goals where the branches of the first goal
- % contain extra information about the switched on variable
- % of the second goal.
- simplify__merge_adjacent_switches(Goal1, Goal, RevGoals0,
- RevGoals1, BranchInstMaps, Info2, Info3)
- ->
- simplify__conj([Goal | Goals0], RevGoals1, Goals,
- ConjInfo, Info3, Info)
+ simplify__conj(Goals1, RevGoals0, Goals, ConjInfo, Info2, Info)
;
% Delete unreachable goals.
(
- simplify_info_get_instmap(Info2, InstMap1),
+ simplify_info_get_instmap(Info1, InstMap1),
instmap__is_unreachable(InstMap1)
;
Goal1 = _ - GoalInfo1,
@@ -882,7 +918,7 @@
determinism_components(Detism1, _, at_most_zero)
)
->
- Info = Info2,
+ Info = Info1,
simplify__conjoin_goal_and_rev_goal_list(Goal1,
RevGoals0, RevGoals1),
@@ -905,28 +941,18 @@
),
list__reverse(RevGoals, Goals)
;
- Goal1 = GoalExpr - _,
- ( goal_util__goal_is_branched(GoalExpr) ->
- Info4 = Info2,
- GoalNeeded = yes,
- Goals1 = Goals0,
- RevGoals1 = RevGoals0
- ;
- simplify_info_set_branch_info(Info2, BranchInstMaps,
- Info3),
- simplify__excess_assigns(Goal1, ConjInfo,
- Goals0, Goals1, RevGoals0, RevGoals1,
- GoalNeeded, Info3, Info4)
- ),
+ simplify__excess_assigns(Goal1, ConjInfo,
+ Goals0, Goals1, RevGoals0, RevGoals1,
+ GoalNeeded, Info1, Info2),
( GoalNeeded = yes ->
simplify__conjoin_goal_and_rev_goal_list(Goal1,
RevGoals1, RevGoals2)
;
RevGoals2 = RevGoals1
),
- simplify_info_update_instmap(Info4, Goal1, Info5),
+ simplify_info_update_instmap(Info2, Goal1, Info3),
simplify__conj(Goals1, RevGoals2, Goals,
- ConjInfo, Info5, Info)
+ ConjInfo, Info3, Info)
)
).
@@ -943,173 +969,6 @@
%-----------------------------------------------------------------------------%
- % Check the post-branch instmaps from the last branching structure in
- % the conjunction to see if there was more information about the
- % switched on variable at the end of each branch than there is at the
- % start of the current switch. If there is, it may be worth merging the
- % goals.
-:- pred simplify__merge_adjacent_switches(hlds_goal::in, hlds_goal::out,
- hlds_goals::in, hlds_goals::out, maybe(branch_info)::in,
- simplify_info::in, simplify_info::out) is semidet.
-
-simplify__merge_adjacent_switches(SwitchGoal, Goal, RevGoals0, RevGoals,
- MaybeBranchInfo, Info0, Info) :-
- MaybeBranchInfo = yes(branch_info(RevInstMapDeltas,
- PreGoalCommon, PreGoalInstMap)),
- simplify_do_switch(Info0),
- list__reverse(RevInstMapDeltas, BranchInstMaps),
- BranchInstMaps \= [],
- BranchInstMaps \= [_],
- SwitchGoal = switch(Var, _, Cases2, SM) - _,
- move_follow_code_select(RevGoals0, RevFollowGoals, RevGoals1),
- RevGoals1 = [BranchedGoal | RevGoals],
- BranchedGoal = BranchedGoalExpr - BranchedGoalInfo,
- goal_util__goal_is_branched(BranchedGoalExpr),
- simplify_info_get_instmap(Info0, InstMap),
- simplify__check_branches_for_extra_info(Var, InstMap,
- BranchInstMaps, Cases2, [], RevCaseList),
- list__reverse(RevCaseList, CaseList),
- list__reverse(RevFollowGoals, FollowGoals),
- (
- BranchedGoalExpr = switch(Var1, CanFail1, Cases1, _)
- ->
- simplify__merge_switch_into_cases(Cases1,
- FollowGoals, CaseList, Cases),
- GoalExpr = switch(Var1, CanFail1, Cases, SM)
- ;
- BranchedGoalExpr = if_then_else(Vars, Cond,
- Then0, Else0, IteSM)
- ->
- CaseList = [ThenCase, ElseCase],
- simplify__merge_switch_into_goal(Then0, FollowGoals,
- ThenCase, Then),
- simplify__merge_switch_into_goal(Else0, FollowGoals,
- ElseCase, Else),
- GoalExpr = if_then_else(Vars, Cond, Then, Else, IteSM)
- ;
- BranchedGoalExpr = disj(Disjuncts0, DisjSM)
- ->
- simplify__merge_switch_into_goals(Disjuncts0,
- FollowGoals, CaseList, Disjuncts),
- GoalExpr = disj(Disjuncts, DisjSM)
- ;
- error("simplify__merge_adjacent_switches")
- ),
- list__append(FollowGoals, [SwitchGoal], NewGoals),
- simplify__approximate_goal_info(NewGoals, BranchedGoalInfo, GoalInfo),
- Goal = GoalExpr - GoalInfo,
- simplify_info_set_requantify(Info0, Info1),
- simplify_info_set_common_info(Info1, PreGoalCommon, Info2),
- simplify_info_set_instmap(Info2, PreGoalInstMap, Info3),
- simplify_info_reset_branch_info(Info3, Info, _).
-
- % This just checks if every case in the second switch either fails
- % or matches only one case given the information in the branches of
- % the first branching goal. Returns the goal for the case that
- % applies for each branch's instmap delta.
-:- pred simplify__check_branches_for_extra_info(var::in,
- instmap::in, list(instmap_delta)::in, list(case)::in,
- list(hlds_goal)::in, list(hlds_goal)::out) is semidet.
-
-simplify__check_branches_for_extra_info(_, _, [], _, CaseList, CaseList).
-simplify__check_branches_for_extra_info(Var, InstMap,
- [BranchInstMap | BranchInstMaps], Cases, CaseList0, CaseList) :-
- instmap__lookup_var(InstMap, Var, InstMapInst),
- ( instmap_delta_search_var(BranchInstMap, Var, BranchInstMapInst0) ->
- BranchInstMapInst = BranchInstMapInst0
- ;
- BranchInstMapInst = InstMapInst
- ),
- simplify__inst_contains_more_information(BranchInstMapInst,
- InstMapInst, Cases, ThisCase),
- simplify__check_branches_for_extra_info(Var, InstMap,
- BranchInstMaps, Cases, [ThisCase | CaseList0], CaseList).
-
-:- pred simplify__inst_contains_more_information((inst)::in,
- (inst)::in, list(case)::in, hlds_goal::out) is semidet.
-
-simplify__inst_contains_more_information(not_reached, _, _, Goal) :-
- fail_goal(Goal).
-simplify__inst_contains_more_information(bound(_, BoundInsts),
- _, Cases0, Goal) :-
- functors_to_cons_ids(BoundInsts, ConsIds0),
- list__sort(ConsIds0, ConsIds),
- delete_unreachable_cases(Cases0, ConsIds, Cases),
- (
- Cases = [],
- fail_goal(Goal)
- ;
- Cases = [case(_, Goal)]
- ).
-
-:- pred simplify__merge_switch_into_goals(hlds_goals::in, hlds_goals::in,
- list(hlds_goal)::in, hlds_goals::out) is det.
-
-simplify__merge_switch_into_goals([], _, [], []).
-simplify__merge_switch_into_goals([], _, [_|_], []) :-
- error("simplify__merge_switch_into_goals").
-simplify__merge_switch_into_goals([_|_], _, [], []) :-
- error("simplify__merge_switch_into_goals").
-simplify__merge_switch_into_goals([Goal0 | Goals0], Builtins,
- [SwitchGoal | SwitchGoals], [Goal | Goals]) :-
- simplify__merge_switch_into_goal(Goal0, Builtins, SwitchGoal, Goal),
- simplify__merge_switch_into_goals(Goals0, Builtins, SwitchGoals, Goals).
-
-:- pred simplify__merge_switch_into_cases(list(case)::in, hlds_goals::in,
- list(hlds_goal)::in, list(case)::out) is det.
-
-simplify__merge_switch_into_cases([], _, [], []).
-simplify__merge_switch_into_cases([], _, [_|_], []) :-
- error("simplify__merge_switch_into_cases").
-simplify__merge_switch_into_cases([_|_], _, [], []) :-
- error("simplify__merge_switch_into_cases").
-simplify__merge_switch_into_cases([case(ConsId, Goal0) | Cases0], Builtins,
- [SwitchGoal | SwitchGoals], [case(ConsId, Goal) | Cases]) :-
- simplify__merge_switch_into_goal(Goal0, Builtins, SwitchGoal, Goal),
- simplify__merge_switch_into_cases(Cases0, Builtins, SwitchGoals, Cases).
-
-:- pred simplify__merge_switch_into_goal(hlds_goal::in, hlds_goals::in,
- hlds_goal::in, hlds_goal::out) is det.
-
-simplify__merge_switch_into_goal(Goal0, Builtins, SwitchGoal, Goal) :-
- conjoin_goal_and_goal_list(Goal0, Builtins, Goal1),
- conjoin_goals(Goal1, SwitchGoal, Goal2),
- Goal2 = GoalExpr - GoalInfo0,
- ( GoalExpr = conj(Goals) ->
- simplify__approximate_goal_info(Goals, GoalInfo0, GoalInfo)
- ;
- GoalInfo = GoalInfo0
- ),
- Goal = GoalExpr - GoalInfo.
-
- % Create a conservative goal_info so that simplification can
- % safely be re-run on the resulting goal. A full recomputation over
- % the entire goal is done later.
-:- pred simplify__approximate_goal_info(list(hlds_goal)::in,
- hlds_goal_info::in, hlds_goal_info::out) is det.
-
-simplify__approximate_goal_info(NewGoals, GoalInfo0, GoalInfo) :-
- ComputeGoalInfo =
- lambda([Goal::in, GInfo0::in, GInfo::out] is det, (
- Goal = _ - GInfo1,
- goal_info_get_nonlocals(GInfo0, NonLocals0),
- goal_info_get_instmap_delta(GInfo0, InstMapDelta0),
- goal_info_get_instmap_delta(GInfo1, InstMapDelta1),
- instmap_delta_apply_instmap_delta(InstMapDelta0,
- InstMapDelta1, InstMapDelta),
- goal_info_get_nonlocals(GInfo1, NonLocals1),
- set__union(NonLocals0, NonLocals1, NonLocals),
- goal_info_set_instmap_delta(GInfo0, InstMapDelta, GInfo2),
- goal_info_set_nonlocals(GInfo2, NonLocals, GInfo3),
- goal_info_get_determinism(GInfo3, Detism0),
- goal_info_get_determinism(GInfo1, Detism1),
- det_conjunction_detism(Detism0, Detism1, Detism),
- goal_info_set_determinism(GInfo3, Detism, GInfo)
- )),
- list__foldl(ComputeGoalInfo, NewGoals, GoalInfo0, GoalInfo).
-
-%-----------------------------------------------------------------------------%
-
:- pred simplify__excess_assigns(hlds_goal::in, hlds_goal_info::in,
hlds_goals::in, hlds_goals::out,
hlds_goals::in, hlds_goals::out, bool::out,
@@ -1137,30 +996,9 @@
Subn, Goals),
goal_util__rename_vars_in_goals(RevGoals0, no,
Subn, RevGoals),
- simplify_info_reset_branch_info(Info0, Info1, BranchInfo0),
- (
- BranchInfo0 = yes(
- branch_info(InstMapDeltas0,
- Common, PreBranchInstMap0))
- ->
- simplify_info_get_instmap(Info1, InstMap0),
- instmap__apply_sub(PreBranchInstMap0, no,
- Subn, PreBranchInstMap),
- instmap__apply_sub(InstMap0, no, Subn, InstMap),
- Lambda = lambda([Delta0::in, Delta::out] is det, (
- instmap_delta_apply_sub(Delta0, no, Subn, Delta)
- )),
- list__map(Lambda, InstMapDeltas0, InstMapDeltas),
- simplify_info_set_instmap(Info1, InstMap, Info2),
- simplify_info_set_branch_info(Info2,
- yes(branch_info(InstMapDeltas,
- Common, PreBranchInstMap)), Info3)
- ;
- Info3 = Info1
- ),
- simplify_info_get_varset(Info3, VarSet0),
+ simplify_info_get_varset(Info0, VarSet0),
varset__delete_var(VarSet0, LocalVar, VarSet),
- simplify_info_set_varset(Info3, VarSet, Info)
+ simplify_info_set_varset(Info0, VarSet, Info)
;
GoalNeeded = yes,
Goals = Goals0,
@@ -1170,27 +1008,59 @@
%-----------------------------------------------------------------------------%
-:- pred simplify__switch(var, list(case), list(case), list(instmap_delta),
- list(instmap_delta), simplify_info, simplify_info, simplify_info).
-:- mode simplify__switch(in, in, out, in, out, in, in, out) is det.
-
-simplify__switch(_, [], [], InstMaps, InstMaps, _, Info, Info).
-simplify__switch(Var, [Case0 | Cases0], [Case | Cases],
- InstMaps0, InstMaps, Info0, Info1, Info) :-
+:- pred simplify__switch(var, list(case), list(case), list(case),
+ list(instmap_delta), list(instmap_delta), can_fail, can_fail,
+ simplify_info, simplify_info, simplify_info).
+:- mode simplify__switch(in, in, in, out, in, out, in, out,
+ in, in, out) is det.
+
+simplify__switch(_, [], RevCases, Cases, InstMaps, InstMaps,
+ CanFail, CanFail, _, Info, Info) :-
+ list__reverse(RevCases, Cases).
+simplify__switch(Var, [Case0 | Cases0], RevCases0, Cases, InstMaps0, InstMaps,
+ CanFail0, CanFail, Info0, Info1, Info) :-
simplify_info_get_instmap(Info0, InstMap0),
Case0 = case(ConsId, Goal0),
simplify_info_get_module_info(Info1, ModuleInfo0),
instmap__bind_var_to_functor(Var, ConsId,
- InstMap0, InstMap1, ModuleInfo0, ModuleInfo),
- simplify_info_set_module_info(Info1, ModuleInfo, Info2),
+ InstMap0, InstMap1, ModuleInfo0, ModuleInfo1),
+ simplify_info_set_module_info(Info1, ModuleInfo1, Info2),
simplify_info_set_instmap(Info2, InstMap1, Info3),
simplify__goal(Goal0, Goal, Info3, Info4),
- simplify_info_post_branch_update(Info0, Info4, Info5),
- Case = case(ConsId, Goal),
- Goal = _ - GoalInfo,
- goal_info_get_instmap_delta(GoalInfo, InstMapDelta),
- simplify__switch(Var, Cases0, Cases, [InstMapDelta | InstMaps0],
- InstMaps, Info0, Info5, Info).
+
+ % Remove failing branches.
+ ( Goal = disj([], _) - _ ->
+ RevCases = RevCases0,
+ InstMaps1 = InstMaps0,
+ CanFail1 = can_fail,
+ Info5 = Info4
+ ;
+ Case = case(ConsId, Goal),
+ Goal = _ - GoalInfo,
+
+ %
+ % Make sure the switched on variable appears in the
+ % instmap delta. This avoids an abort in merge_instmap_delta
+ % if another branch further instantiates the switched-on
+ % variable. If the switched on variable does not appear in
+ % this branch's instmap_delta, the inst before the goal
+ % would be used, resulting in a mode error.
+ %
+ goal_info_get_instmap_delta(GoalInfo, InstMapDelta0),
+ simplify_info_get_module_info(Info4, ModuleInfo5),
+ instmap_delta_bind_var_to_functor(Var, ConsId,
+ InstMap0, InstMapDelta0, InstMapDelta,
+ ModuleInfo5, ModuleInfo),
+ simplify_info_set_module_info(Info4, ModuleInfo, Info5),
+
+ InstMaps1 = [InstMapDelta | InstMaps0],
+ RevCases = [Case | RevCases0],
+ CanFail1 = CanFail0
+ ),
+
+ simplify_info_post_branch_update(Info0, Info5, Info6),
+ simplify__switch(Var, Cases0, RevCases, Cases, InstMaps1, InstMaps,
+ CanFail1, CanFail, Info0, Info6, Info).
% Create a semidet unification at the start of a singleton case
% in a can_fail switch.
@@ -1240,34 +1110,74 @@
%-----------------------------------------------------------------------------%
-:- pred simplify__disj(list(hlds_goal), list(hlds_goal), list(instmap_delta),
- list(instmap_delta), simplify_info, simplify_info, simplify_info).
-:- mode simplify__disj(in, out, in, out, in, in, out) is det.
+:- pred simplify__disj(list(hlds_goal), list(hlds_goal), list(hlds_goal),
+ list(instmap_delta), list(instmap_delta),
+ simplify_info, simplify_info, simplify_info).
+:- mode simplify__disj(in, in, out, in, out, in, in, out) is det.
-simplify__disj([], [], InstMaps, InstMaps, _, Info, Info).
-simplify__disj([Goal0 |Goals0], [Goal | Goals], PostBranchInstMaps0,
+simplify__disj([], RevGoals, Goals, InstMaps, InstMaps, _, Info, Info) :-
+ list__reverse(RevGoals, Goals).
+simplify__disj([Goal0 | Goals0], RevGoals0, Goals, PostBranchInstMaps0,
PostBranchInstMaps, Info0, Info1, Info) :-
simplify__goal(Goal0, Goal, Info1, Info2),
- simplify_info_post_branch_update(Info0, Info2, Info3),
- Goal0 = _ - GoalInfo,
- goal_info_get_instmap_delta(GoalInfo, InstMapDelta),
- simplify__disj(Goals0, Goals, [InstMapDelta | PostBranchInstMaps0],
- PostBranchInstMaps, Info0, Info3, Info4),
+ Goal = _ - GoalInfo,
+
(
- simplify_do_warn(Info4),
- Goal = _ - GoalInfo,
- % don't warn about impure disjuncts that can't succeed
+ % Don't prune or warn about impure disjuncts
+ % that can't succeed.
\+ goal_info_is_impure(GoalInfo),
goal_info_get_determinism(GoalInfo, Detism),
- determinism_components(Detism, _, MaxSolns),
+ determinism_components(Detism, CanFail, MaxSolns),
MaxSolns = at_most_zero
->
- goal_info_get_context(GoalInfo, Context),
- simplify_info_add_msg(Info4, zero_soln_disjunct(Context),
- Info)
+ (
+ simplify_do_warn(Info2),
+ % Don't warn where the initial goal was fail,
+ % since that can result from mode analysis
+ % pruning away cases in a switch which cannot
+ % succeed due to sub-typing in the modes.
+ Goal0 \= disj([], _) - _
+ ->
+ goal_info_get_context(GoalInfo, Context),
+ simplify_info_add_msg(Info2,
+ zero_soln_disjunct(Context), Info3)
+ ;
+ Info3 = Info2
+ ),
+
+ %
+ % Prune away non-succeeding disjuncts where possible.
+ %
+
+ (
+ (
+ CanFail = can_fail
+ ;
+ % Only remove erroneous disjuncts
+ % if --no-fully-strict.
+ CanFail = cannot_fail,
+ simplify_info_get_det_info(Info3, DetInfo),
+ det_info_get_fully_strict(DetInfo, no)
+ )
+ ->
+ RevGoals1 = RevGoals0,
+ PostBranchInstMaps1 = PostBranchInstMaps0
+ ;
+ RevGoals1 = [Goal | RevGoals0],
+ goal_info_get_instmap_delta(GoalInfo, InstMapDelta),
+ PostBranchInstMaps1 =
+ [InstMapDelta | PostBranchInstMaps0]
+ )
;
- Info = Info4
- ).
+ Info3 = Info2,
+ RevGoals1 = [Goal | RevGoals0],
+ goal_info_get_instmap_delta(GoalInfo, InstMapDelta),
+ PostBranchInstMaps1 = [InstMapDelta | PostBranchInstMaps0]
+ ),
+
+ simplify_info_post_branch_update(Info0, Info3, Info4),
+ simplify__disj(Goals0, RevGoals1, Goals, PostBranchInstMaps1,
+ PostBranchInstMaps, Info0, Info4, Info).
% Disjunctions that cannot succeed more than once when viewed from the
% outside generally need some fixing up, and/or some warnings to be
@@ -1383,31 +1293,37 @@
bool, % Does the goal need requantification.
bool, % Does mode analysis need rerunning
% rather than recompute_instmap_delta.
- maybe(branch_info), % Final instmaps at the end
- % of each branch of the last
- % branching goal
+ unit,
+ int, % Measure of the improvement in
+ % the goal from simplification.
int % Count of the number of lambdas
% which enclose the current goal.
).
- % info used to merge adjacent switches and prepare for rerunning
- % simplification on the resulting goal.
-:- type branch_info
- ---> branch_info(
- list(instmap_delta), % instmap_delta for each branch
- common_info, % from before goal
- instmap % from before goal
- ).
-
simplify_info_init(DetInfo, Simplify, InstMap, VarSet, VarTypes, Info) :-
common_info_init(CommonInfo),
set__init(Msgs),
Info = simplify_info(DetInfo, Msgs, Simplify, CommonInfo,
- InstMap, VarSet, VarTypes, no, no, no, 0).
+ InstMap, VarSet, VarTypes, no, no, unit, 0, 0).
+
+ % Reinitialise the simplify_info before reprocessing a goal.
+:- pred simplify_info_reinit(simplify::in, instmap::in,
+ simplify_info::in, simplify_info::out) is det.
+
+simplify_info_reinit(Simplify, InstMap0, Info0, Info) :-
+ Info0 = simplify_info(DetInfo, Msgs, _, _, _,
+ VarSet, VarTypes, _, _, _, CostDelta, _),
+ common_info_init(Common),
+ Info = simplify_info(DetInfo, Msgs, Simplify, Common, InstMap0,
+ VarSet, VarTypes, no, no, unit, CostDelta, 0).
% exported for common.m
:- interface.
+:- pred simplify_info_init(det_info, simplify, instmap,
+ varset, map(var, type), simplify_info).
+:- mode simplify_info_init(in, in, in, in, in, out) is det.
+
:- pred simplify_info_get_det_info(simplify_info::in, det_info::out) is det.
:- pred simplify_info_get_msgs(simplify_info::in, set(det_msg)::out) is det.
:- pred simplify_info_get_instmap(simplify_info::in, instmap::out) is det.
@@ -1419,29 +1335,29 @@
map(var, type)::out) is det.
:- pred simplify_info_requantify(simplify_info::in) is semidet.
:- pred simplify_info_recompute_atomic(simplify_info::in) is semidet.
-:- pred simplify_info_get_branch_info(simplify_info::in,
- maybe(branch_info)::out) is det.
+:- pred simplify_info_get_cost_delta(simplify_info::in, int::out) is det.
:- pred simplify_info_get_module_info(simplify_info::in,
module_info::out) is det.
:- implementation.
-simplify_info_get_det_info(simplify_info(Det, _,_,_,_,_,_,_,_,_,_), Det).
-simplify_info_get_msgs(simplify_info(_, Msgs, _,_,_,_,_,_,_,_,_), Msgs).
-simplify_info_get_simplify(simplify_info(_,_,Simplify,_,_,_,_,_,_,_,_),
+simplify_info_get_det_info(simplify_info(Det, _,_,_,_,_,_,_,_,_,_,_), Det).
+simplify_info_get_msgs(simplify_info(_, Msgs, _,_,_,_,_,_,_,_,_,_), Msgs).
+simplify_info_get_simplify(simplify_info(_,_,Simplify,_,_,_,_,_,_,_,_,_),
Simplify).
-simplify_info_get_common_info(simplify_info(_,_,_,Common, _,_,_,_,_,_,_),
+simplify_info_get_common_info(simplify_info(_,_,_,Common, _,_,_,_,_,_,_,_),
Common).
-simplify_info_get_instmap(simplify_info(_,_,_,_, InstMap,_,_,_,_,_,_),
- InstMap).
-simplify_info_get_varset(simplify_info(_,_,_,_,_, VarSet, _,_,_,_,_), VarSet).
-simplify_info_get_var_types(simplify_info(_,_,_,_,_,_, VarTypes, _,_,_,_),
+simplify_info_get_instmap(simplify_info(_,_,_,_, InstMap,_,_,_,_,_,_,_),
+ InstMap).
+simplify_info_get_varset(simplify_info(_,_,_,_,_, VarSet, _,_,_,_,_,_), VarSet).
+simplify_info_get_var_types(simplify_info(_,_,_,_,_,_, VarTypes, _,_,_,_,_),
VarTypes).
-simplify_info_requantify(simplify_info(_,_,_,_,_,_,_, yes, _,_,_)).
-simplify_info_recompute_atomic(simplify_info(_,_,_,_,_,_,_,_, yes,_,_)).
-simplify_info_get_branch_info(simplify_info(_,_,_,_,_,_,_,_,_, BranchInfo, _),
- BranchInfo).
+simplify_info_requantify(simplify_info(_,_,_,_,_,_,_, yes, _,_,_,_)).
+simplify_info_recompute_atomic(simplify_info(_,_,_,_,_,_,_,_, yes,_,_,_)).
+simplify_info_get_cost_delta(simplify_info(_,_,_,_,_,_,_,_,_,_,CostDelta, _),
+ CostDelta).
+
simplify_info_get_module_info(Info, ModuleInfo) :-
simplify_info_get_det_info(Info, DetInfo),
@@ -1449,8 +1365,6 @@
:- interface.
-:- type branch_info.
-
:- pred simplify_info_set_det_info(simplify_info::in,
det_info::in, simplify_info::out) is det.
:- pred simplify_info_set_msgs(simplify_info::in,
@@ -1469,12 +1383,13 @@
simplify_info::out) is det.
:- pred simplify_info_set_recompute_atomic(simplify_info::in,
simplify_info::out) is det.
-:- pred simplify_info_reset_branch_info(simplify_info::in, simplify_info::out,
- maybe(branch_info)::out) is det.
-:- pred simplify_info_set_branch_info(simplify_info::in,
- maybe(branch_info)::in, simplify_info::out) is det.
:- pred simplify_info_add_msg(simplify_info::in, det_msg::in,
simplify_info::out) is det.
+:- pred simplify_info_set_cost_delta(simplify_info::in, int::in,
+ simplify_info::out) is det.
+:- pred simplify_info_incr_cost_delta(simplify_info::in,
+ int::in, simplify_info::out) is det.
+
:- pred simplify_info_enter_lambda(simplify_info::in, simplify_info::out)
is det.
:- pred simplify_info_leave_lambda(simplify_info::in, simplify_info::out)
@@ -1486,30 +1401,34 @@
:- implementation.
-simplify_info_set_det_info(simplify_info(_, B, C, D, E, F, G, H, I, J, K), Det,
- simplify_info(Det, B, C, D, E, F, G, H, I, J, K)).
-simplify_info_set_msgs(simplify_info(A, _, C, D, E, F, G, H, I, J, K), Msgs,
- simplify_info(A, Msgs, C, D, E, F, G, H, I, J, K)).
-simplify_info_set_simplify(simplify_info(A, B, _, D, E, F, G, H, I, J, K), Simp,
- simplify_info(A, B, Simp, D, E, F, G, H, I, J, K)).
-simplify_info_set_instmap(simplify_info(A, B, C, D, _, F, G, H, I, J, K),
- InstMap, simplify_info(A, B, C, D, InstMap, F, G, H, I, J, K)).
-simplify_info_set_common_info(simplify_info(A, B, C, _, E, F, G, H, I, J, K),
- Common, simplify_info(A, B, C, Common, E, F, G, H, I, J, K)).
-simplify_info_set_varset(simplify_info(A, B, C, D, E, _, G, H, I, J, K), VarSet,
- simplify_info(A, B, C, D, E, VarSet, G, H, I, J, K)).
-simplify_info_set_var_types(simplify_info(A, B, C, D, E, F, _, H, I, J, K),
- VarTypes, simplify_info(A, B, C, D, E, F, VarTypes, H, I, J, K)).
-simplify_info_set_requantify(simplify_info(A, B, C, D, E, F, G, _, I, J, K),
- simplify_info(A, B, C, D, E, F, G, yes, I, J, K)).
-simplify_info_set_recompute_atomic(
- simplify_info(A, B, C, D, E, F, G, H, _, J, K),
- simplify_info(A, B, C, D, E, F, G, H, yes, J, K)).
-simplify_info_reset_branch_info(
- simplify_info(A, B, C, D, E, F, G, H, I, Info, K),
- simplify_info(A, B, C, D, E, F, G, H, I, no, K), Info).
-simplify_info_set_branch_info(simplify_info(A, B, C, D, E, F, G, H, I, _, K),
- Info, simplify_info(A, B, C, D, E, F, G, H, I, Info, K)).
+simplify_info_set_det_info(simplify_info(_, B, C, D, E, F, G, H, I, J, K, L),
+ Det, simplify_info(Det, B, C, D, E, F, G, H, I, J, K, L)).
+simplify_info_set_msgs(simplify_info(A, _, C, D, E, F, G, H, I, J, K, L), Msgs,
+ simplify_info(A, Msgs, C, D, E, F, G, H, I, J, K, L)).
+simplify_info_set_simplify(simplify_info(A, B, _, D, E, F, G, H, I, J, K, L),
+ Simp, simplify_info(A, B, Simp, D, E, F, G, H, I, J, K, L)).
+simplify_info_set_instmap(simplify_info(A, B, C, D, _, F, G, H, I, J, K, L),
+ InstMap,
+ simplify_info(A, B, C, D, InstMap, F, G, H, I, J, K, L)).
+simplify_info_set_common_info(simplify_info(A, B, C, _, E, F, G, H, I, J, K, L),
+ Common,
+ simplify_info(A, B, C, Common, E, F, G, H, I, J, K, L)).
+simplify_info_set_varset(simplify_info(A, B, C, D, E, _, G, H, I, J, K, L),
+ VarSet,
+ simplify_info(A, B, C, D, E, VarSet, G, H, I, J, K, L)).
+simplify_info_set_var_types(simplify_info(A, B, C, D, E, F, _, H, I, J, K, L),
+ VarTypes, simplify_info(A, B, C, D, E, F, VarTypes, H,I,J,K,L)).
+simplify_info_set_requantify(simplify_info(A, B, C, D, E, F, G, _, I, J, K, L),
+ simplify_info(A, B, C, D, E, F, G, yes, I, J, K, L)).
+simplify_info_set_recompute_atomic(simplify_info(A, B, C, D, E, F, G,H,_,J,K,L),
+ simplify_info(A, B, C, D, E, F, G, H, yes, J, K, L)).
+simplify_info_set_cost_delta(simplify_info(A, B, C, D, E, F, G, H, I, J, _, L),
+ Delta, simplify_info(A, B, C, D, E, F, G, H, I, J, Delta, L)).
+
+simplify_info_incr_cost_delta(
+ simplify_info(A, B, C, D, E, F,G,H,I,J, Delta0, L),
+ Incr, simplify_info(A, B, C, D, E, F, G, H, I, J, Delta, L)) :-
+ Delta is Delta0 + Incr.
simplify_info_add_msg(Info0, Msg, Info) :-
( simplify_do_warn(Info0) ->
@@ -1521,12 +1440,12 @@
).
simplify_info_enter_lambda(
- simplify_info(A, B, C, D, E, F, G, H, I, J, LambdaCount0),
- simplify_info(A, B, C, D, E, F, G, H, I, J, LambdaCount)) :-
+ simplify_info(A, B, C, D, E, F, G, H, I, J, K, LambdaCount0),
+ simplify_info(A, B, C, D, E, F, G, H, I, J, K, LambdaCount)) :-
LambdaCount is LambdaCount0 + 1.
simplify_info_leave_lambda(
- simplify_info(A, B, C, D, E, F, G, H, I, J, LambdaCount0),
- simplify_info(A, B, C, D, E, F, G, H, I, J, LambdaCount)) :-
+ simplify_info(A, B, C, D, E, F, G, H, I, J, K, LambdaCount0),
+ simplify_info(A, B, C, D, E, F, G, H, I, J, K, LambdaCount)) :-
LambdaCount1 is LambdaCount0 - 1,
(
LambdaCount1 >= 0
@@ -1536,7 +1455,7 @@
error("simplify_info_leave_lambda: Left too many lambdas")
).
simplify_info_inside_lambda(
- simplify_info(_,_,_,_,_,_,_,_,_,_,LambdaCount)) :-
+ simplify_info(_,_,_,_,_,_,_,_,_,_,_,LambdaCount)) :-
LambdaCount > 0.
simplify_info_set_module_info(Info0, ModuleInfo, Info) :-
@@ -1549,11 +1468,11 @@
:- pred simplify_do_warn(simplify_info::in) is semidet.
:- pred simplify_do_warn_calls(simplify_info::in) is semidet.
:- pred simplify_do_once(simplify_info::in) is semidet.
-:- pred simplify_do_switch(simplify_info::in) is semidet.
:- pred simplify_do_common(simplify_info::in) is semidet.
:- pred simplify_do_excess_assigns(simplify_info::in) is semidet.
:- pred simplify_do_calls(simplify_info::in) is semidet.
:- pred simplify_do_const_prop(simplify_info::in) is semidet.
+:- pred simplify_do_more_common(simplify_info::in) is semidet.
:- implementation.
@@ -1566,28 +1485,28 @@
simplify_do_once(Info) :-
simplify_info_get_simplify(Info, Simplify),
Simplify = simplify(_, _, yes, _, _, _, _, _).
-simplify_do_switch(Info) :-
- simplify_info_get_simplify(Info, Simplify),
- Simplify = simplify(_, _, _, yes, _, _, _, _).
simplify_do_common(Info) :-
simplify_info_get_simplify(Info, Simplify),
- Simplify = simplify(_, _, _, _, yes, _, _, _).
+ Simplify = simplify(_, _, _, yes, _, _, _, _).
simplify_do_excess_assigns(Info) :-
simplify_info_get_simplify(Info, Simplify),
- Simplify = simplify(_, _, _, _, _, yes, _, _).
+ Simplify = simplify(_, _, _, _, yes, _, _, _).
simplify_do_calls(Info) :-
simplify_info_get_simplify(Info, Simplify),
- Simplify = simplify(_, _, _, _, _, _, yes, _).
+ Simplify = simplify(_, _, _, _, _, yes, _, _).
simplify_do_const_prop(Info) :-
simplify_info_get_simplify(Info, Simplify),
+ Simplify = simplify(_, _, _, _, _, _, yes, _).
+simplify_do_more_common(Info) :-
+ simplify_info_get_simplify(Info, Simplify),
Simplify = simplify(_, _, _, _, _, _, _, yes).
:- pred simplify_info_update_instmap(simplify_info::in, hlds_goal::in,
simplify_info::out) is det.
simplify_info_update_instmap(
- simplify_info(A, B, C, D, InstMap0, F, G, H, I, J, K), Goal,
- simplify_info(A, B, C, D, InstMap, F, G, H, I, J, K)) :-
+ simplify_info(A, B, C, D, InstMap0, F, G, H, I, J, K, L), Goal,
+ simplify_info(A, B, C, D, InstMap, F, G, H, I, J, K, L)) :-
update_instmap(Goal, InstMap0, InstMap).
:- type before_after
@@ -1600,11 +1519,17 @@
% would cause more variables to be live across the stack flush.
% Calls and construction unifications are not treated in this
% way since it is nearly always better to optimize them away.
+ % When doing deforestation, it may be better to remove
+ % as many common structures as possible.
:- pred simplify_info_maybe_clear_structs(before_after::in, hlds_goal::in,
simplify_info::in, simplify_info::out) is det.
simplify_info_maybe_clear_structs(BeforeAfter, Goal, Info0, Info) :-
- ( code_util__cannot_stack_flush(Goal) ->
+ (
+ ( code_util__cannot_stack_flush(Goal)
+ ; simplify_do_more_common(Info0)
+ )
+ ->
Info = Info0
;
% First check to see if a call is common and can be replaced
@@ -1617,6 +1542,7 @@
Goal = GoalExpr - _,
GoalExpr \= call(_, _, _, _, _, _),
GoalExpr \= higher_order_call(_, _, _, _, _, _),
+ GoalExpr \= class_method_call(_, _, _, _, _, _),
GoalExpr \= pragma_c_code(_, _, _, _, _, _, _)
)
->
@@ -1636,15 +1562,6 @@
simplify_info_set_instmap(PostBranchInfo0, InstMap, PostBranchInfo1),
simplify_info_get_common_info(PreBranchInfo, Common),
simplify_info_set_common_info(PostBranchInfo1, Common, Info).
-
-:- pred simplify_info_create_branch_info(simplify_info::in, simplify_info::in,
- list(instmap_delta)::in, simplify_info::out) is det.
-
-simplify_info_create_branch_info(Info0, Info1, InstMapDeltas, Info) :-
- simplify_info_get_common_info(Info0, Common),
- simplify_info_get_instmap(Info0, InstMap),
- BranchInfo = yes(branch_info(InstMapDeltas, Common, InstMap)),
- simplify_info_set_branch_info(Info1, BranchInfo, Info).
% Undo updates to the simplify_info before redoing
% simplification on a goal.
@@ -1654,7 +1571,5 @@
simplify_info_undo_goal_updates(Info1, Info2, Info) :-
simplify_info_get_common_info(Info1, CommonInfo0),
simplify_info_set_common_info(Info2, CommonInfo0, Info3),
- simplify_info_get_branch_info(Info1, BranchInfo),
- simplify_info_set_branch_info(Info3, BranchInfo, Info4),
simplify_info_get_instmap(Info1, InstMap),
- simplify_info_set_instmap(Info4, InstMap, Info).
+ simplify_info_set_instmap(Info3, InstMap, Info).
Index: doc/user_guide.texi
===================================================================
RCS file: /home/staff/zs/imp/mercury/doc/user_guide.texi,v
retrieving revision 1.117
diff -u -r1.117 user_guide.texi
--- user_guide.texi 1998/02/09 10:24:08 1.117
+++ user_guide.texi 1998/02/19 03:34:07
@@ -2342,9 +2342,11 @@
Reorder goals to minimize the number of variables
that have to be saved across calls.
- at c @sp 1
- at c @item --no-specialize
- at c Disable the specialization of procedures.
+ at sp 1
+ at item --deforestation
+Enable deforestation. The aim of deforestation is to avoid
+the construction of intermediate data structures and to avoid
+repeated traversals over data structures within a conjunction.
@end table
Index: library/varset.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/library/varset.m,v
retrieving revision 1.56
diff -u -r1.56 varset.m
--- varset.m 1998/01/08 08:11:32 1.56
+++ varset.m 1998/02/18 04:53:20
@@ -146,6 +146,11 @@
:- pred varset__ensure_unique_names(list(var), string, varset, varset).
:- mode varset__ensure_unique_names(in, in, in, out) is det.
+ % Given a varset and a set of variables, return another varset
+ % containing only those variables.
+:- pred varset__select(varset, set(var), varset).
+:- mode varset__select(in, in, out) is det.
+
%-----------------------------------------------------------------------------%
:- implementation.
@@ -416,6 +421,13 @@
;
Final = Trial0
).
+
+%-----------------------------------------------------------------------------%
+
+varset__select(varset(Supply, VarNameMap0, Values0), Vars,
+ varset(Supply, VarNameMap, Values)) :-
+ map__select(VarNameMap0, Vars, VarNameMap),
+ map__select(Values0, Vars, Values).
%-----------------------------------------------------------------------------%
%-----------------------------------------------------------------------------%
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