diff: .agc liveness in ite.

[Tyson Richard DOWD]

Hi,

Another bugfix for liveness with accurate gc - this one was a fairly
simple oversight.

===================================================================

Estimated hours taken: 1

Fix a bug in liveness that causes a sanity check to fail for accurate
gc.

compiler/liveness.m:
	Handle if-then-else correctly for .agc grades, it wasn't
	handling polymorphic type variables correctly.

tests/valid/Mmake:
tests/valid/agc_ite.m:
	Add a test case for if-then-else - previously the compiler
	aborted on this test case.

Index: compiler/liveness.m
===================================================================
RCS file: /home/staff/zs/imp/mercury/compiler/liveness.m,v
retrieving revision 1.74
diff -u -r1.74 liveness.m
--- liveness.m	1997/05/21 02:13:30	1.74
+++ liveness.m	1997/06/20 05:51:41
@@ -373,7 +373,20 @@
 	detect_deadness_in_goal(Cond0, DeadnessThen, LiveInfo,
 		DeadnessCond, Cond1),
 
-	goal_info_get_nonlocals(GoalInfo, NonLocals),
+	goal_info_get_nonlocals(GoalInfo, NonLocals0),
+	live_info_get_module_info(LiveInfo, ModuleInfo),
+	module_info_globals(ModuleInfo, Globals),
+	globals__get_gc_method(Globals, GCmethod),
+	(
+		GCmethod = accurate
+	->
+		live_info_get_proc_info(LiveInfo, ProcInfo),
+		proc_info_get_typeinfo_vars_setwise(ProcInfo, NonLocals0, 
+			TypeInfoVars),
+		set__union(NonLocals0, TypeInfoVars, NonLocals)
+	;
+		NonLocals = NonLocals0
+	),
 	set__union(DeadnessCond, DeadnessElse, Deadness),
 	set__intersect(Deadness, NonLocals, NonLocalDeadness),
 
Index: tests/valid/Mmake
===================================================================
RCS file: /home/staff/zs/imp/tests/valid/Mmake,v
retrieving revision 1.40
diff -u -r1.40 Mmake
--- Mmake	1997/06/18 07:26:04	1.40
+++ Mmake	1997/06/20 06:00:00
@@ -8,6 +8,7 @@
 
 # please keep this list sorted
 SOURCES= \
+	agc_ite.m \
 	agc_unbound_typevars.m \
 	agc_unbound_typevars2.m \
 	agc_unused_in.m \
@@ -78,6 +79,7 @@
 
 # some regression tests only failed with particular options enabled
 # (please keep this list sorted)
+GRADE-agc_ite			= asm_fast.agc
 GRADE-agc_unbound_typevars	= asm_fast.agc
 GRADE-agc_unbound_typevars2	= asm_fast.agc
 GRADE-agc_unused_in		= asm_fast.agc

New File: tests/valid/agc_ite.m
===================================================================
% 
% Regression test.
%
% Name: agc_ite.m
%
% Description of bug:
% 	The liveness of polymorphic type variables for accurate gc
% 	wasn't being computed correctly in the case of if-then-else.
%
% Symptom(s) of bug:
% 	A sanity check in liveness.m is failed.
%
% 		Software error: branches of if-then-else disagree on liveness
% 		Then: HeadVar__3 TypeInfo_for_Y 
%	 	Else: HeadVar__3 TypeInfo_for_X TypeInfo_for_Y 
%
%
% Date bug existed: 19-June-1997
%
% Author: trd

:- module agc_ite.

:- interface.

:- import_module list.

:- pred agc_ite__filter_map(pred(X, Y), list(X), list(Y)).
:- mode agc_ite__filter_map(pred(in, out) is semidet, in, out) is det.

:- implementation.
	
agc_ite__filter_map(_, [],  []).
agc_ite__filter_map(Pred, [Head0|Tail0], List) :-
	( call(Pred, Head0, Head) ->
		List = [Head|List1]
	;
		List = List1
	),
	agc_ite__filter_map(Pred, Tail0, List1).



-- 
       Tyson Dowd           # 
                            #  Surreal humour isn't eveyone's cup of
     trd at cs.mu.oz.au        #  fur.
http://www.cs.mu.oz.au/~trd #