Goal expansion in lib reif

benches/reif.pl

@@ -0,0 +1,63 @@
+/*
+Copied from^W^W Inspired by memberbench[1], but has only benchmarks relevant to
+goal expansion of if_/3 and is adapted to be better integrated into Scryer's
+benchmarking subsystem: which doesn't need time reporting, and supports only
+single test at a time.
+
+[1]: http://www.complang.tuwien.ac.at/ulrich/Prolog-inedit/sicstus/memberbench.pl
+*/
+
+:- use_module(library(reif)).
+:- use_module(library(lists)).
+:- use_module(library(si)).
+
+
+run(Test, Count) :-
+   atom_si(Test),
+   integer_si(Count),
+   exptrue(Count),
+   \+ benchmark(Test, z, "abcdefghijklmnopqrstuvwxyz ")
+   ; true.
+
+
+% Baseline test – the fastest possible implementation
+benchmark(memberchk,   E, Es) :- memberchk(E, Es).
+
+% Expanded if_/3
+benchmark(memberd_ifc, E, Es) :- memberd_ifc(E, Es).
+
+% Non-expanded if_/3
+benchmark(memberd_fif, E, Es) :- memberd_fif(E, Es).
+
+
+memberd_ifc(X, [E|Es]) :-
+   if_(X = E, true, memberd_ifc(X, Es)).
+
+memberd_fif(X, [E|Es]) :-
+   fif_(X = E, true, memberd_fif(X, Es)).
+
+
+% Copy of _if/3, but with a different name, so it won't be expanded
+fif_(If_1, Then_0, Else_0) :-
+    call(If_1, T),
+    (  T == true  -> Then_0
+    ;  T == false -> Else_0
+    ;  nonvar(T) -> throw(error(type_error(boolean, T), _))
+    ;  throw(error(instantiation_error, _))
+    ).
+
+
+%% exptrue(N).
+%
+% Succeeds 10^N times if N is ground, usefull as a cheap way to repeat a given
+% predicate many times in benchmarks. There are many more ways to generate
+% choice points, but this one by far has the lowest overhead.
+exptrue(0).
+exptrue(1) :- ten.
+exptrue(2) :- ten, ten.
+exptrue(3) :- ten, ten, ten.
+exptrue(4) :- ten, ten, ten, ten.
+exptrue(5) :- ten, ten, ten, ten, ten.
+exptrue(6) :- ten, ten, ten, ten, ten, ten.
+
+ten. ten. ten. ten. ten. ten. ten. ten. ten. ten.

benches/run_iai.rs

@@ -13,6 +13,9 @@ mod iai {
     #[bench::count_edges(setup::prolog_benches()["count_edges"].setup())]
     #[bench::numlist(setup::prolog_benches()["numlist"].setup())]
     #[bench::csv_codename(setup::prolog_benches()["csv_codename"].setup())]
+    #[bench::memberbench_baseline(setup::prolog_benches()["memberbench_baseline"].setup())]
+    #[bench::memberbench_if_expanded(setup::prolog_benches()["memberbench_if_expanded"].setup())]
+    #[bench::memberbench_if_not_expanded(setup::prolog_benches()["memberbench_if_not_expanded"].setup())]
     fn bench(mut run: impl FnMut() -> Vec<LeafAnswer>) -> Vec<LeafAnswer> {
         run()
     }

benches/setup.rs

@@ -26,6 +26,33 @@ pub fn prolog_benches() -> BTreeMap<&'static str, PrologBenchmark> {
             Strategy::Reuse,
             btreemap! { "Name" => Term::string("SPACE") },
         ),
+        /* FIXME: Following 3 benchmarks don't bind any variables and shouldn't
+         * produce any leaf answer, but test validate_benchmarks() fails if last
+         * element is `btreemap! {}`, because result of a query is `[True]`, but
+         * test case expects `[LeafAnswer { bindings: {} }]`. As a workaround
+         * I've just added dummy variable unification.
+         */
+        (
+            "memberbench_baseline",
+            "benches/reif.pl",
+            "run(memberchk,4),X=done.",
+            Strategy::Reuse,
+            btreemap! { "X" => Term::atom("done") },
+        ),
+        (
+            "memberbench_if_expanded",
+            "benches/reif.pl",
+            "run(memberd_ifc,4),Y=done.",
+            Strategy::Reuse,
+            btreemap! { "Y" => Term::atom("done") },
+        ),
+        (
+            "memberbench_if_not_expanded",
+            "benches/reif.pl",
+            "run(memberd_fif,4),Z=done.",
+            Strategy::Reuse,
+            btreemap! { "Z" => Term::atom("done") },
+        ),
     ]
     .map(|b| {
         (