caseql: generate better code.

* eval.c (me_case): Replace a code generation pattern of the
(if (and x y) z) with the equivalent (and x y z). The
motivation behind this is that it effectively coaxes a
jump-threading optimization out of our simplistic compiler.
The failure cases out of a single *and* all jump past the
entire code block, whereas with the cascaded if + and we get
a double test of the same failed value threading through two
branches.

1 files changed, 7 insertions, 9 deletions

diff --git a/eval.c b/eval.c
index c35dab1d..2f803a70 100644
--- a/eval.c
+++ b/eval.c
@@ -4027,15 +4027,13 @@ static val me_case(val form, val menv)
       return list(let_s, list(list(tformsym, testform, nao),
                               list(swres, uniq, nao),
                               nao),
-                  list(if_s,
-                       list(and_s,
-                            list(intern(if3(all_keys_integer,
-                                            lit("integerp"), lit("chrp")),
-                                        user_package),
-                                 tformsym, nao),
-                            list(intern(lit("<="), user_package),
-                                 minkey, tformsym, maxkey, nao),
-                            nao),
+                  list(and_s,
+                       list(intern(if3(all_keys_integer,
+                                       lit("integerp"), lit("chrp")),
+                                   user_package),
+                            tformsym, nao),
+                       list(intern(lit("<="), user_package),
+                            minkey, tformsym, maxkey, nao),
                        list(set_s,
                             swres,
                             list(switch_s,