2016-08-29 Jim Meyering <meyering@fb.com>
+ intprops.h, xalloc-oversized.h: work with gcc 7
+ In gcc 6, __builtin_add_overflow, __builtin_sub_overflow and
+ __builtin_mul_overflow each accept a NULL pointer as the third
+ argument. However in gcc 7, that is no longer accepted.
+ Instead, one must use the "_p"-suffixed names, with which, the
+ third parameter is no longer a pointer.
+ * lib/intprops.h (_GL_HAS_BUILTIN_OVERFLOW_WITH_NULL): Correct
+ the definition: not true for gcc 7 and subsequent.
+ (_GL_HAS_BUILTIN_OVERFLOW_P): Define.
+ (_GL_ADD_OVERFLOW, _GL_SUBTRACT_OVERFLOW, _GL_MULTIPLY_OVERFLOW):
+ Provide new definitions for gcc 7 and subsequent.
+ * lib/xalloc-oversized.h (xalloc_oversized): Provide a definition
+ that works with gcc-7.
+
intprops.h: fix missing-backslash problems
* lib/intprops.h (_GL_ADD_OVERFLOW): Add backslash.
(_GL_SUBTRACT_OVERFLOW,_GL_MULTIPLY_OVERFLOW): Likewise.
: (max) >> (b) < (a))
/* True if __builtin_add_overflow (A, B, P) works when P is null. */
-#define _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL (7 <= __GNUC__)
+#define _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL (6 == __GNUC__)
+
+/* True if __builtin_add_overflow_p (A, B, C) works. */
+#define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
/* The _GL*_OVERFLOW macros have the same restrictions as the
*_RANGE_OVERFLOW macros, except that they do not assume that operands
(e.g., A and B) have the same type as MIN and MAX. Instead, they assume
that the result (e.g., A + B) has that type. */
-#if _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL
+#if _GL_HAS_BUILTIN_OVERFLOW_P
+# define _GL_ADD_OVERFLOW(a, b, min, max) \
+ __builtin_add_overflow_p (a, b, (a) + (b))
+# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
+ __builtin_sub_overflow_p (a, b, (a) - (b))
+# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
+ __builtin_mul_overflow_p (a, b, (a) * (b))
+#elif _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL
# define _GL_ADD_OVERFLOW(a, b, min, max) \
__builtin_add_overflow (a, b, (__typeof__ ((a) + (b)) *) 0)
# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
nonnegative. This is a macro, not a function, so that it
works correctly even when SIZE_MAX < N. */
-/* GCC 7 __builtin_mul_overflow should easily compute this. See:
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68120 */
#if 7 <= __GNUC__
+# define xalloc_oversized(n, s) __builtin_mul_overflow_p (n, s, (size_t) 1)
+
+/* GCC 6 __builtin_mul_overflow should easily compute this. See:
+ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68120 */
+#elif 6 == __GNUC__
# define xalloc_oversized(n, s) __builtin_mul_overflow (n, s, (size_t *) NULL)
/* GCC 5 and Clang __builtin_mul_overflow needs a temporary, and