Negate only values while constraining variables (bug#45376)

	* lisp/emacs-lisp/comp-cstr.el (comp-cstr-value-negation): New
	function.
	* lisp/emacs-lisp/comp.el (comp-fwprop-insn): Use
	`comp-cstr-value-negation'.
	* test/src/comp-test-funcs.el (comp-test-45376-1-f): Rename.
	(comp-test-45376-2-f): New funcion.
	* test/src/comp-tests.el (bug-45376-1): Rename test.
	(bug-45376-2): Add test.

2 files changed, 25 insertions, 3 deletions

diff --git a/test/src/comp-test-funcs.el b/test/src/comp-test-funcs.el
index d6bcfca2d94..7731e6547b1 100644
--- a/test/src/comp-test-funcs.el
+++ b/test/src/comp-test-funcs.el
@@ -417,7 +417,7 @@
         (setq args (cons (substring arg start pos) args))))
     args))
 
-(defun comp-test-45376-f ()
+(defun comp-test-45376-1-f ()
   ;; Reduced from `eshell-ls-find-column-lengths'.
   (let* (res
          (len 2)
@@ -431,6 +431,24 @@
             i (1+ i)))
     res))
 
+(defun comp-test-45376-2-f ()
+  ;; Also reduced from `eshell-ls-find-column-lengths'.
+  (let* ((x 1)
+         res)
+    (while x
+      (let* ((y 4)
+             (i 0))
+        (while (> y 0)
+          (when (= i x)
+            (setq i 0))
+          (setf res (cons i res))
+          (setq y (1- y)
+                i (1+ i)))
+        (if (>= x 3)
+            (setq x nil)
+          (setq x (1+ x)))))
+    res))
+
 
 ;;;;;;;;;;;;;;;;;;;;
 ;; Tromey's tests ;;
diff --git a/test/src/comp-tests.el b/test/src/comp-tests.el
index 5f2d702fca0..e0d4bf8df5e 100644
--- a/test/src/comp-tests.el
+++ b/test/src/comp-tests.el
@@ -409,9 +409,13 @@ https://lists.gnu.org/archive/html/bug-gnu-emacs/2020-03/msg00914.html."
   "Broken call args assumptions lead to infinite loop."
   (should (equal (comp-test-assume-in-loop-1-f "cd") '("cd"))))
 
-(comp-deftest bug-45376 ()
+(comp-deftest bug-45376-1 ()
   "<https://lists.gnu.org/archive/html/bug-gnu-emacs/2020-12/msg01883.html>"
-  (should (equal (comp-test-45376-f) '(1 0))))
+  (should (equal (comp-test-45376-1-f) '(1 0))))
+
+(comp-deftest bug-45376-2 ()
+  "<https://lists.gnu.org/archive/html/bug-gnu-emacs/2020-12/msg01883.html>"
+  (should (equal (comp-test-45376-2-f) '(0 2 1 0 1 0 1 0 0 0 0 0))))
 
 (defvar comp-test-primitive-advice)
 (comp-deftest primitive-advice ()