[m-rev.] for review: loop hoist const goals

[Fergus Henderson]

Estimated hours taken: 1
Branches: main

Enable loop invariant hoisting for goals that have no input arguments.

compiler/loop_inv.m:
	Delete the code which was explicitly disabling loop invariant
	hoisting for "const goals", i.e. goals that have no input arguments.
	(Why was this code there in the first place?)

tests/hard_coded/Mmakefile:
	Enable loop_inv_test1, since we now pass it.

tests/hard_coded/loop_inv_test1.exp:
	New file, containing the expected output for this test.

tests/hard_coded/loop_inv_test1.m:
	Delete the comment which said that we don't pass this test.

Workspace: /home/jupiter/fjh/ws-jupiter/mercury
Index: compiler/loop_inv.m
===================================================================
RCS file: /home/mercury1/repository/mercury/compiler/loop_inv.m,v
retrieving revision 1.6
diff -u -d -r1.6 loop_inv.m
--- compiler/loop_inv.m	31 Oct 2003 03:27:24 -0000	1.6
+++ compiler/loop_inv.m	9 Feb 2004 06:18:18 -0000
@@ -601,7 +601,6 @@
     ( if
         (   const_construction(Goal)
         ;   deconstruction(Goal)
-        ;   const_goal(MI, Goal)
         ;   impure_goal(Goal)
         )
       then
@@ -634,16 +633,6 @@
 
 deconstruction(GoalExpr - _GoalInfo) :-
     GoalExpr ^ unify_kind = deconstruct(_, _, _, _, _, _).
-
-%------------------------------------------------------------------------------%
-
-    % A const goal has no inputs.
-    %
-:- pred const_goal(module_info, hlds_goal).
-:- mode const_goal(in, in) is semidet.
-
-const_goal(ModuleInfo, Goal) :-
-    goal_inputs(ModuleInfo, Goal) = [].
 
 %------------------------------------------------------------------------------%
 
Index: tests/hard_coded/Mmakefile
===================================================================
RCS file: /home/mercury1/repository/tests/hard_coded/Mmakefile,v
retrieving revision 1.221
diff -u -d -r1.221 Mmakefile
--- tests/hard_coded/Mmakefile	9 Feb 2004 08:32:58 -0000	1.221
+++ tests/hard_coded/Mmakefile	9 Feb 2004 08:33:59 -0000
@@ -101,6 +101,7 @@
 	intermod_type_qual \
 	join_list \
 	loop_inv_test \
+	loop_inv_test1 \
 	mapped_module \
 	merge_and_remove_dups \
 	minint_bug \
@@ -294,7 +295,7 @@
 #     floats in Mercury aren't consistent -- see the comments at the
 #     top of library/float.m.
 #
-# XXX loop_inv_test0, loop_inv_test1, loop_inv_test2:
+# XXX loop_inv_test0, loop_inv_test2:
 #     These test cases test some more sophisticated cases of loop invariant
 #     optimization which are current loop_inv pass is not capable of
 #     optimizing.
Index: tests/hard_coded/loop_inv_test1.exp
===================================================================
RCS file: tests/hard_coded/loop_inv_test1.exp
diff -N tests/hard_coded/loop_inv_test1.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/hard_coded/loop_inv_test1.exp	9 Feb 2004 08:38:40 -0000
@@ -0,0 +1,3 @@
+enter two integers, one on each line
+R1 = 4233
+R2 = 5333
Index: tests/hard_coded/loop_inv_test1.m
===================================================================
RCS file: /home/mercury1/repository/tests/hard_coded/loop_inv_test1.m,v
retrieving revision 1.2
diff -u -d -r1.2 loop_inv_test1.m
--- tests/hard_coded/loop_inv_test1.m	9 Feb 2004 08:32:59 -0000	1.2
+++ tests/hard_coded/loop_inv_test1.m	9 Feb 2004 08:38:15 -0000
@@ -11,11 +11,6 @@
 % This test checks that we do loop invariant hoisting for
 % invariant goals which have no input arguments.
 
-% XXX We do not yet pass this test case, because the loop invariant 
-%     pass has some code which explicitly disables the optimization
-%     if there are no input arguments. (Why???)
-%     This should be very easy to fix.
-
 :- module loop_inv_test1.
 :- interface.
 :- import_module io.

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