From 33ef3ac7854adece095e69ea8fb0e70fb1feeea6 Mon Sep 17 00:00:00 2001 From: "Arnold D. Robbins" Date: Mon, 8 Feb 2021 09:04:43 +0200 Subject: Updates from GNULIB, including major work on regex. --- support/intprops.h | 50 +++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 43 insertions(+), 7 deletions(-) (limited to 'support/intprops.h') diff --git a/support/intprops.h b/support/intprops.h index cb086715..967e32ea 100644 --- a/support/intprops.h +++ b/support/intprops.h @@ -1,6 +1,6 @@ /* intprops.h -- properties of integer types - Copyright (C) 2001-2020 Free Software Foundation, Inc. + Copyright (C) 2001-2021 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published @@ -226,7 +226,9 @@ /* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow (A, B, P) work when P is non-null. */ -#if 5 <= __GNUC__ && !defined __ICC +/* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x, + see . */ +#if 7 <= __GNUC__ && !defined __ICC # define _GL_HAS_BUILTIN_ADD_OVERFLOW 1 #elif defined __has_builtin # define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow) @@ -244,10 +246,14 @@ /* True if __builtin_add_overflow_p (A, B, C) works, and similarly for __builtin_sub_overflow_p and __builtin_mul_overflow_p. */ -#ifdef __clang__ -/* Clang 9 lacks __builtin_mul_overflow_p, and even if it did it would - presumably run afoul of Clang bug 16404. */ +#if defined __clang__ || defined __ICC +/* Clang 11 lacks __builtin_mul_overflow_p, and even if it did it + would presumably run afoul of Clang bug 16404. ICC 2021.1's + __builtin_add_overflow_p etc. are not treated as integral constant + expressions even when all arguments are. */ # define _GL_HAS_BUILTIN_OVERFLOW_P 0 +#elif defined __has_builtin +# define _GL_HAS_BUILTIN_OVERFLOW_P __has_builtin (__builtin_mul_overflow_p) #else # define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__) #endif @@ -383,8 +389,9 @@ _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW) #endif #if _GL_HAS_BUILTIN_MUL_OVERFLOW -# if (9 < __GNUC__ + (3 <= __GNUC_MINOR__) \ - || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) +# if ((9 < __GNUC__ + (3 <= __GNUC_MINOR__) \ + || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) \ + && !defined __ICC) # define INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r) # else /* Work around GCC bug 91450. */ @@ -591,4 +598,33 @@ : (tmin) / (a) < (b)) \ : (tmax) / (b) < (a))) +/* The following macros compute A + B, A - B, and A * B, respectively. + If no overflow occurs, they set *R to the result and return 1; + otherwise, they return 0 and may modify *R. + + Example usage: + + long int result; + if (INT_ADD_OK (a, b, &result)) + printf ("result is %ld\n", result); + else + printf ("overflow\n"); + + A, B, and *R should be integers; they need not be the same type, + and they need not be all signed or all unsigned. + + These macros work correctly on all known practical hosts, and do not rely + on undefined behavior due to signed arithmetic overflow. + + These macros are not constant expressions. + + These macros may evaluate their arguments zero or multiple times, so the + arguments should not have side effects. + + These macros are tuned for B being a constant. */ + +#define INT_ADD_OK(a, b, r) ! INT_ADD_WRAPV (a, b, r) +#define INT_SUBTRACT_OK(a, b, r) ! INT_SUBTRACT_WRAPV (a, b, r) +#define INT_MULTIPLY_OK(a, b, r) ! INT_MULTIPLY_WRAPV (a, b, r) + #endif /* _GL_INTPROPS_H */ -- cgit v1.2.3