Improve XFIXNUM cleanup a bit

Based on Pip Cet’s review (Bug#36370#13).
* src/ccl.c (Fccl_execute_on_string): Use clearer indexing.
* src/dosfns.c (Fint86, Fdos_memput):
Avoid runtime checks for negative fixnums when debugging.
This restores the earlier machine code.
* src/lisp.h (XFIXNUM, XUFIXNUM): Use eassert, not eassume.
(XFIXNAT): At the start, merely eassert FIXNUMP rather
than eassuming FIXNATP.  At the end, eassume that the
result is nonnegative.  This restores help to the compiler
that the previous patch mistakenly removed.

1 files changed, 6 insertions, 4 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 077d2360654..a0619e64f20 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -1195,7 +1195,7 @@ INLINE bool
 INLINE EMACS_INT
 XFIXNUM (Lisp_Object a)
 {
-  eassume (FIXNUMP (a));
+  eassert (FIXNUMP (a));
   return XFIXNUM_RAW (a);
 }
 
@@ -1209,7 +1209,7 @@ XUFIXNUM_RAW (Lisp_Object a)
 INLINE EMACS_UINT
 XUFIXNUM (Lisp_Object a)
 {
-  eassume (FIXNUMP (a));
+  eassert (FIXNUMP (a));
   return XUFIXNUM_RAW (a);
 }
 
@@ -2828,9 +2828,11 @@ FIXNATP (Lisp_Object x)
 INLINE EMACS_INT
 XFIXNAT (Lisp_Object a)
 {
-  eassume (FIXNATP (a));
+  eassert (FIXNUMP (a));
   EMACS_INT int0 = Lisp_Int0;
-  return USE_LSB_TAG ? XFIXNUM (a) : XLI (a) - (int0 << VALBITS);
+  EMACS_INT result = USE_LSB_TAG ? XFIXNUM (a) : XLI (a) - (int0 << VALBITS);
+  eassume (0 <= result);
+  return result;
 }
 
 INLINE bool