[m-rev.] for review: fix documentation of `--no-fully-strict'

[Julien Fischer]

For review by anyone (preferably by Ian if he is around.)

Estimated hours taken: 0.5
Branches: main

Address bug #18: the documentation of the option `--no-fully-strict'
no longer matched what the implementation was doing.

Fix a incorrect warning message.

compiler/options.m:
doc/reference_manual.texi:
doc/user_guide.texi:
 	Revert the incorrect part of Ian's previous change to the
 	documentation of `--no-fully-strict'.

 	Rather than, awkwardly, referring to "calls to error/1 or throw/1",
 	just refer to "goals with determinism erroneous", which is more
 	general and closer to what the implementation actually does.

compiler/simplify.m:
 	Fix an incorrect verbose warning: compiling with `--fully-strict'
 	is *not* sufficient to prevent the compiler replacing goals that
 	always fail with false.  The compiler may still perform such
 	replacements even if `--fully-strict' is enabled, so long as the goal
 	can be proven to terminate and is not erroneous.

Julien.

Index: compiler/options.m
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/compiler/options.m,v
retrieving revision 1.599
diff -u -r1.599 options.m
--- compiler/options.m	6 Nov 2007 05:25:08 -0000	1.599
+++ compiler/options.m	6 Nov 2007 05:57:27 -0000
@@ -3503,10 +3503,8 @@
          "--no-reorder-disj",
          "\tExecute disjunctions strictly left-to-right.",
          "--no-fully-strict",
-        "\tAllow mmc to optimize away infinite loops or calls to error/1.",
-        "\tAlso allow mmc to replace (semi)pure det goals that have no",
-        "\toutputs with `true' and replace (semi)pure goals that will",
-        "\talways fail with `fail'.",
+        "\tAllow infinite loops or goals with determinism erroneous to be",
+        "\toptimised away.",
          "--allow-stubs",
          "\tAllow procedures to have no clauses.  Any calls to",
          "\tsuch procedures will raise an exception at run-time.",
Index: compiler/simplify.m
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/compiler/simplify.m,v
retrieving revision 1.218
diff -u -r1.218 simplify.m
--- compiler/simplify.m	10 Oct 2007 14:35:27 -0000	1.218
+++ compiler/simplify.m	6 Nov 2007 05:57:27 -0000
@@ -650,11 +650,10 @@
              )
          ->
              MainPieces = [words("Warning: this goal cannot succeed.")],
-            VerbosePieces =
-                [words("The compiler will optimize away this goal,"),
-                words("replacing it with `fail'."),
-                words("To disable this optimization, use"),
-                words("the `--fully-strict' option.")],
+            VerbosePieces = [
+                words("The compiler will optimize away this goal,"),
+                words("replacing it with `fail'.")
+            ],
              Msg = simple_msg(Context,
                  [option_is_set(warn_simple_code, yes,
                      [always(MainPieces), verbose_only(VerbosePieces)])]),
Index: doc/reference_manual.texi
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/doc/reference_manual.texi,v
retrieving revision 1.411
diff -u -r1.411 reference_manual.texi
--- doc/reference_manual.texi	31 Oct 2007 03:58:25 -0000	1.411
+++ doc/reference_manual.texi	6 Nov 2007 05:57:27 -0000
@@ -6148,9 +6148,8 @@
  combinations of the @samp{--no-reorder-conj}, @samp{--no-reorder-disj},
  and @samp{--no-fully-strict} options.
  (The @samp{--no-fully-strict} option allows the compiler to improve
-completeness by optimizing away infinite loops,
-calls to @code{require.error/1} or @code{exception.throw/1} and
-(semi)pure goals that are declaratively equivalent to true or false.)
+completeness by optimizing away infinite loops and goals with determinism
+ at code{erroneous}.)
  The default semantics are the strict commutative semantics.
  Enabling @samp{--no-reorder-conj} and @samp{--no-reorder-disj} gives the
  strict sequential semantics.
Index: doc/user_guide.texi
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/doc/user_guide.texi,v
retrieving revision 1.550
diff -u -r1.550 user_guide.texi
--- doc/user_guide.texi	6 Nov 2007 05:25:09 -0000	1.550
+++ doc/user_guide.texi	6 Nov 2007 05:57:27 -0000
@@ -6908,11 +6908,8 @@
  @sp 1
  @item --no-fully-strict
  @findex --no-fully-strict
-Allow the compiler to optimize away infinite loops or calls to
- at code{error/1} or @code{throw/1}.
-Also allow the compiler to replace det (semi)pure goals that have no outputs
-with @samp{true}
-and (semi)pure goals that will always fail with @samp{fail}.
+Allow infinite loops or goals with determinism erroneous to be optimised
+away.

  @sp 1
  @item --allow-stubs

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