Mattias Engdegård reported that the Emacs master source currently
generates the following warning when Emacs is built with mini-gmp.c
under Clang 13:
In file included from /Users/mattias/emacs/lib/mini-gmp-gnulib.c:47:
/Users/mattias/emacs/lib/mini-gmp.c:1138:2: warning: unused variable '__cy'
[-Wunused-variable]
gmp_assert_nocarry (mpn_rshift (np, np, dn, shift));
^
/Users/mattias/emacs/lib/mini-gmp.c:91:15: note: expanded from macro
'gmp_assert_nocarry'
mp_limb_t __cy = (x); \
The problem occurs because assert(X) does not evaluate X when NDEBUG is
defined. Proposed patch attached.
Another advantage of this patch is that any messages generated by
assertion failures are more informative.diff -r d45103d658ca mini-gmp/mini-gmp.c
--- a/mini-gmp/mini-gmp.c Wed Mar 30 23:16:18 2022 +0200
+++ b/mini-gmp/mini-gmp.c Fri Apr 08 16:18:06 2022 -0700
@@ -87,10 +87,11 @@
#define GMP_MPN_OVERLAP_P(xp, xsize, yp, ysize) \
((xp) + (xsize) > (yp) && (yp) + (ysize) > (xp))
-#define gmp_assert_nocarry(x) do { \
- mp_limb_t __cy = (x); \
- assert (__cy == 0); \
- } while (0)
+#ifdef NDEBUG
+# define gmp_assert_nocarry(x) ((void) (x))
+#else
+# define gmp_assert_nocarry(x) assert ((x) == 0)
+#endif
#define gmp_clz(count, x) do { \
mp_limb_t __clz_x = (x); \
_______________________________________________
gmp-bugs mailing list
gmp-bugs@gmplib.org
https://gmplib.org/mailman/listinfo/gmp-bugs
