From 92a501022e0154cd9de41240680b7f003a833c96 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Fri, 13 Nov 2015 12:39:13 -0800 Subject: Merge from gnulib This incorporates: 2015-11-13 xalloc-oversized: improve performance with GCC 5 * lib/xalloc-oversized.h: Copy from gnulib. --- lib/xalloc-oversized.h | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/xalloc-oversized.h b/lib/xalloc-oversized.h index f0e9778f738..0e579deb2bb 100644 --- a/lib/xalloc-oversized.h +++ b/lib/xalloc-oversized.h @@ -16,9 +16,13 @@ along with this program. If not, see . */ #ifndef XALLOC_OVERSIZED_H_ -# define XALLOC_OVERSIZED_H_ +#define XALLOC_OVERSIZED_H_ -# include +#include + +#ifndef __has_builtin +# define __has_builtin(x) 0 +#endif /* Return 1 if an array of N objects, each of size S, cannot exist due to size arithmetic overflow. S must be positive and N must be @@ -32,7 +36,12 @@ sizeof (ptrdiff_t) <= sizeof (size_t), so do not bother to test for exactly-SIZE_MAX allocations on such hosts; this avoids a test and branch when S is known to be 1. */ +#if 5 <= __GNUC__ || __has_builtin (__builtin_mul_overflow) +# define xalloc_oversized(n, s) \ + ({ size_t __xalloc_size; __builtin_mul_overflow (n, s, &__xalloc_size); }) +#else # define xalloc_oversized(n, s) \ ((size_t) (sizeof (ptrdiff_t) <= sizeof (size_t) ? -1 : -2) / (s) < (n)) +#endif #endif /* !XALLOC_OVERSIZED_H_ */ -- cgit v1.2.1