diff: simplify.m bug fix

[Fergus Henderson]

Hi Simon,

Can you please review this one?

compiler/simplify.m:
	Fix a bug: the code was passing around two different copies
	of ModuleInfo, one passed directly, one stored in the det_info
	in the simplify_info, and these were not being kept in sync.
	That caused the final ModuleInfo to contain the wrong merge_inst
	table, which led to map__lookup failures.

tests/valid/Mmake:
tests/valid/lazy_list.m:
	Add regression test for the above bug.

Index: simplify.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/simplify.m,v
retrieving revision 1.37
diff -u -5 -r1.37 simplify.m
--- simplify.m	1997/07/12 17:06:54	1.37
+++ simplify.m	1997/07/12 17:28:59
@@ -70,49 +70,49 @@
 %-----------------------------------------------------------------------------%
 
 simplify__proc(Simplify, PredId, ProcId, ModuleInfo0, ModuleInfo,
 		Proc0, Proc, WarnCnt, ErrCnt, State0, State) :-
 	globals__io_get_globals(Globals, State0, State1),
-	det_info_init(ModuleInfo0, PredId, ProcId, Globals, DetInfo),
+	det_info_init(ModuleInfo0, PredId, ProcId, Globals, DetInfo0),
 	proc_info_get_initial_instmap(Proc0, ModuleInfo0, InstMap0),
 	proc_info_variables(Proc0, VarSet0),
 	proc_info_vartypes(Proc0, VarTypes0),
-	simplify_info_init(DetInfo, Simplify, InstMap0,
+	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),
 	( 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),
 			Info1),
-		simplify__proc_2(Proc0, Proc1, ModuleInfo0, ModuleInfo1,
-			Info1, Info2, State2, State3),
+		simplify__proc_2(Proc0, Proc1, Info1, Info2, State2, State3),
 		simplify_info_get_msgs(Info2, Msgs1),
+		simplify_info_get_det_info(Info2, DetInfo1),
 		proc_info_variables(Proc1, VarSet1),
 		proc_info_vartypes(Proc1, VarTypes1),
-		simplify_info_init(DetInfo,
+		simplify_info_init(DetInfo1,
 			simplify(no, no, Once, no, no, Excess, no),
 			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,
-		ModuleInfo1 = ModuleInfo0,
 		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, ModuleInfo1, ModuleInfo,
-			Info4, Info, State4, State5),
+	simplify__proc_2(Proc1, Proc, Info4, Info, State4, State5),
+	simplify_info_get_module_info(Info, ModuleInfo),
 	simplify_info_get_msgs(Info, Msgs2),
 	set__to_sorted_list(Msgs2, Msgs),
 	( (Warn = yes ; WarnCalls = yes) ->
 		det_report_msgs(Msgs, ModuleInfo, WarnCnt,
 			ErrCnt, State5, State)
@@ -120,40 +120,41 @@
 		WarnCnt = 0,
 		ErrCnt = 0,
 		State = State5
 	).
 
-:- pred simplify__proc_2(proc_info::in, proc_info::out, module_info::in,
-		module_info::out, simplify_info::in, simplify_info::out,
+:- 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, ModuleInfo0, ModuleInfo,
-		Info0, Info, State0, State) :-
+simplify__proc_2(Proc0, Proc, Info0, Info, State0, State) :-
 	proc_info_goal(Proc0, Goal0),
-	simplify__goal(Goal0, Goal, Info0, Info),
-	simplify_info_get_varset(Info, VarSet),
-	simplify_info_get_var_types(Info, VarTypes),
+	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_variables(Proc1, VarSet, Proc2),
 	proc_info_set_vartypes(Proc2, VarTypes, Proc3),
-	( simplify_info_requantify(Info) ->
+	( simplify_info_requantify(Info1) ->
 		requantify_proc(Proc3, Proc4),
-		( simplify_info_recompute_atomic(Info) ->
+		( simplify_info_recompute_atomic(Info1) ->
 			RecomputeAtomic = yes
 		;
 			RecomputeAtomic = no
 		),
 		proc_info_goal(Proc4, Goal2),
-		proc_info_get_initial_instmap(Proc4, ModuleInfo0, InstMap0),
+		simplify_info_get_module_info(Info1, ModuleInfo1),
+		proc_info_get_initial_instmap(Proc4, ModuleInfo1, InstMap0),
 		recompute_instmap_delta(RecomputeAtomic, Goal2, Goal3,
-			InstMap0, ModuleInfo0, ModuleInfo),
+			InstMap0, ModuleInfo1, ModuleInfo),
+		simplify_info_set_module_info(Info1, ModuleInfo, Info),
 		proc_info_set_goal(Proc4, Goal3, Proc),
 		State = State0
 	;
 		Proc = Proc3,
-		ModuleInfo = ModuleInfo0,
-		State = State0
+		State = State0,
+		Info = Info1
 	).
 
 %-----------------------------------------------------------------------------%
 
 simplify__goal(Goal0, Goal - GoalInfo, Info0, Info) :-

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3         |     -- the last words of T. S. Garp.