upstream

1 files changed, 2 insertions, 16 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 8ddc7ef143d..f2177ad789d 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -197,22 +197,8 @@ extern int suppress_checking EXTERNALLY_VISIBLE;
 # if defined DECL_ALIGN
 /* On hosts where VALBITS is greater than the pointer width in bits,
    USE_LSB_TAG is:
-
-    a. unnecessary, because the top bits of an EMACS_INT are unused,
-
-    b. slower, because it typically requires extra masking, and
-
-    c. harmful, because it can create Lisp_Object values that are so scrambled
-       that mark_maybe_object cannot decipher them.  mark_maybe_object assumes
-       that EMACS_INT values are contiguous, but a host where EMACS_INT is
-       wider than a pointer might allocate the top half of an EMACS_INT in
-       (say) a 32-bit word on the stack, putting the bottom half in a 32-bit
-       register that is saved elsewhere in a jmp_buf.  When this happens,
-       since USE_LSB_TAG is not defined the bottom half alone is a valid
-       pointer that mark_maybe_pointer can follow; but if USE_LSB_TAG were
-       defined, the bottom half would not be a valid pointer and neither
-       mark_maybe_object nor mark_maybe_pointer would follow it.
-
+    a. unnecessary, because the top bits of an EMACS_INT are unused, and
+    b. slower, because it typically requires extra masking.
    So, define USE_LSB_TAG only on hosts where it might be useful.  */
 #  if UINTPTR_MAX >> VALBITS != 0
 #   define USE_LSB_TAG