feature/native-comp 672988e 5/9: Symplify (not t) => nil and (not nil) => t

[Andrea Corallo]

branch: feature/native-comp
commit 672988e961744750d3ea40904807355336116c3f
Author: Andrea Corallo <akrl@sdf.org>
Commit: Andrea Corallo <akrl@sdf.org>

    Symplify (not t) => nil and (not nil) => t
    
        * lisp/emacs-lisp/comp-cstr.el (comp-cstr-negation): Symplify (not
        t) => nil and (not nil) => t.
        * test/lisp/emacs-lisp/comp-cstr-tests.el
        (comp-cstr-typespec-tests-alist): Add two tests.
---
 lisp/emacs-lisp/comp-cstr.el            | 25 +++++++++++++++++++++----
 test/lisp/emacs-lisp/comp-cstr-tests.el |  6 +++++-
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/lisp/emacs-lisp/comp-cstr.el b/lisp/emacs-lisp/comp-cstr.el
index 8b5639c..1990595 100644
--- a/lisp/emacs-lisp/comp-cstr.el
+++ b/lisp/emacs-lisp/comp-cstr.el
@@ -695,10 +695,27 @@ DST is returned."
   "Negate SRC setting the result in DST.
 DST is returned."
   (with-comp-cstr-accessors
-    (setf (typeset dst) (typeset src)
-          (valset dst) (valset src)
-          (range dst) (range src)
-          (neg dst) (not (neg src)))
+    (cond
+     ((and (null (valset src))
+           (null (range src))
+           (null (neg src))
+           (equal (typeset src) '(t)))
+      (setf (typeset dst) ()
+            (valset dst) ()
+            (range dst) nil
+            (neg dst) nil))
+     ((and (null (valset src))
+           (null (range src))
+           (null (neg src))
+           (null (typeset src)))
+      (setf (typeset dst) '(t)
+            (valset dst) ()
+            (range dst) nil
+            (neg dst) nil))
+     (t (setf (typeset dst) (typeset src)
+              (valset dst) (valset src)
+              (range dst) (range src)
+              (neg dst) (not (neg src)))))
     dst))
 
 (defun comp-cstr-value-negation (dst src)
diff --git a/test/lisp/emacs-lisp/comp-cstr-tests.el 
b/test/lisp/emacs-lisp/comp-cstr-tests.el
index 834f440..1e1376b 100644
--- a/test/lisp/emacs-lisp/comp-cstr-tests.el
+++ b/test/lisp/emacs-lisp/comp-cstr-tests.el
@@ -203,7 +203,11 @@
       ;; 81
       ((and t (not t)) . nil)
       ;; 82
-      ((or (integer 1 1) (not (integer 1 1))) . t))
+      ((or (integer 1 1) (not (integer 1 1))) . t)
+      ;; 83
+      ((not t) . nil)
+      ;; 84
+      ((not nil) . t))
     "Alist type specifier -> expected type specifier."))
 
 (defmacro comp-cstr-synthesize-tests ()