[m-rev.] for review: don't apply a lambda optimisation in erlang grade

[Peter Wang]

Estimated hours taken: 1
Branches: main

Fix a bug in the following optimisation of model_non lambdas:

        % Optimize a special case: replace
        %   `(pred(Y1, Y2, ...) is Detism :-
        %       p(X1, X2, ..., Y1, Y2, ...))'
        % where `p' has determinism `Detism' with
        %   `p(X1, X2, ...)'
        %

For the LLDS back-end the optimisation was also applied when `p' is model_det
but the lambda is model_non.  However it was incorrectly applied for the
erlang grade as well.

compiler/lambda.m:
	Don't apply the optimisation in the case above.

tests/hard_coded/Mmakefile:
tests/hard_coded/nondet_lambda.exp:
tests/hard_coded/nondet_lambda.m:
	Add a test case.

Index: compiler/lambda.m
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/compiler/lambda.m,v
retrieving revision 1.130
diff -u -r1.130 lambda.m
--- compiler/lambda.m	7 Aug 2007 07:09:56 -0000	1.130
+++ compiler/lambda.m	23 Aug 2007 07:20:58 -0000
@@ -395,19 +395,31 @@
         Call_CodeModel = proc_info_interface_code_model(Call_ProcInfo),
         determinism_to_code_model(Detism, CodeModel),
         module_info_get_globals(ModuleInfo0, Globals),
+        globals.get_target(Globals, Target),
         globals.lookup_bool_option(Globals, highlevel_code, HighLevelCode),
         (
-            HighLevelCode = no,
+            ( Target = target_c
+            ; Target = target_il
+            ; Target = target_java
+            ; Target = target_asm
+            ; Target = target_x86_64
+            ),
             (
-                CodeModel = Call_CodeModel
+                HighLevelCode = no,
+                (
+                    CodeModel = Call_CodeModel
+                ;
+                    CodeModel = model_non,
+                    Call_CodeModel = model_det
+                )
             ;
-                CodeModel = model_non,
-                Call_CodeModel = model_det
+                HighLevelCode = yes,
+                Call_PredOrFunc = pred_info_is_pred_or_func(Call_PredInfo),
+                PredOrFunc = Call_PredOrFunc,
+                CodeModel = Call_CodeModel
             )
         ;
-            HighLevelCode = yes,
-            Call_PredOrFunc = pred_info_is_pred_or_func(Call_PredInfo),
-            PredOrFunc = Call_PredOrFunc,
+            Target = target_erlang,
             CodeModel = Call_CodeModel
         ),

Index: tests/hard_coded/Mmakefile
===================================================================
RCS file: /home/mercury/mercury1/repository/tests/hard_coded/Mmakefile,v
retrieving revision 1.330
diff -u -r1.330 Mmakefile
--- tests/hard_coded/Mmakefile	20 Aug 2007 03:36:18 -0000	1.330
+++ tests/hard_coded/Mmakefile	23 Aug 2007 07:20:58 -0000
@@ -152,6 +152,7 @@
 	nonascii \
 	nondet_copy_out \
 	nondet_ctrl_vn \
+	nondet_lambda \
 	nullary_ho_func \
 	one_member \
 	opt_dup_bug \
Index: tests/hard_coded/nondet_lambda.exp
===================================================================
RCS file: tests/hard_coded/nondet_lambda.exp
diff -N tests/hard_coded/nondet_lambda.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/hard_coded/nondet_lambda.exp	23 Aug 2007 07:20:58 -0000
@@ -0,0 +1 @@
+42
Index: tests/hard_coded/nondet_lambda.m
===================================================================
RCS file: tests/hard_coded/nondet_lambda.m
diff -N tests/hard_coded/nondet_lambda.m
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ tests/hard_coded/nondet_lambda.m	23 Aug 2007 07:20:58 -0000
@@ -0,0 +1,23 @@
+:- module nondet_lambda.
+:- interface.
+
+:- import_module io.
+
+:- pred main(io::di, io::uo) is cc_multi.
+
+:- implementation.
+
+main(!IO) :-
+    % The compiler was incorrectly simplifying this to `F = bar' in the erlang
+    % grade.
+    F = (pred(X::out) is nondet :- bar(X)),
+    ( F(Y) ->
+	io__write(Y, !IO),
+	io__write_string("\n", !IO)
+    ;
+	true
+    ).
+
+:- pred bar(int).
+:- mode bar(out) is det.
+bar(42).
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