compiler: forgotten not/null reductions in if.

* stdlib/compiler.tl (compiler comp-if): Recognize
cases like (if (not <expr>) <then> <else>) and
convert to (if <expr> <else> <then>). Also the
test (true <expr>) is reduced to <expr>.

1 files changed, 6 insertions, 0 deletions

diff --git a/stdlib/compiler.tl b/stdlib/compiler.tl
index 5ff71a96..52c9a908 100644
--- a/stdlib/compiler.tl
+++ b/stdlib/compiler.tl
@@ -656,6 +656,12 @@
      me.(compile oreg env nil))
     (((@(member @op %test-funs%) @a @b) . @rest)
      me.(compile oreg env ^(ift ,op ,a ,b ,*rest)))
+    (((@(or not null) @arg) @then @else)
+     me.(comp-if oreg env ^(if ,arg ,else ,then)))
+    (((@(or not null) @arg) @then)
+     me.(comp-if oreg env ^(if ,arg nil ,then)))
+    (((true @arg) . @args)
+     me.(comp-if oreg env ^(if ,arg ,*args)))
     ((@test @then @else)
      (let* ((te-oreg me.(maybe-alloc-treg oreg))
             (lelse (gensym "l"))