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authorAndy Wingo <wingo@pobox.com>2021-01-20 21:52:54 +0100
committerAndy Wingo <wingo@pobox.com>2021-01-20 23:03:56 +0100
commita91b95cca2d397c84f8b9bbd602d40209a7092ce (patch)
tree2c286a291f5a2b812d6e216be10936f2709d59cf /lib/intprops.h
parent758b31994cff582c7e8785b4cc2240dbf3573837 (diff)
downloadguile-a91b95cca2d397c84f8b9bbd602d40209a7092ce.tar.gz
Update Gnulib to v0.1-4379-g2ef5a9b4b
Also bump required autoconf version to 2.64, as required by Gnulib.
Diffstat (limited to 'lib/intprops.h')
-rw-r--r--lib/intprops.h366
1 files changed, 269 insertions, 97 deletions
diff --git a/lib/intprops.h b/lib/intprops.h
index eb06b6917..967e32ea0 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -1,6 +1,6 @@
/* intprops.h -- properties of integer types
- Copyright (C) 2001-2017 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
@@ -13,7 +13,7 @@
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
@@ -21,14 +21,14 @@
#define _GL_INTPROPS_H
#include <limits.h>
-#include <verify.h>
-/* Return a value with the common real type of E and V and the value of V. */
-#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
+/* Return a value with the common real type of E and V and the value of V.
+ Do not evaluate E. */
+#define _GL_INT_CONVERT(e, v) ((1 ? 0 : (e)) + (v))
/* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
- <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00406.html>. */
-#define _GL_INT_NEGATE_CONVERT(e, v) (0 * (e) - (v))
+ <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00406.html>. */
+#define _GL_INT_NEGATE_CONVERT(e, v) ((1 ? 0 : (e)) - (v))
/* The extra casts in the following macros work around compiler bugs,
e.g., in Cray C 5.0.3.0. */
@@ -41,13 +41,14 @@
#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
/* Return 1 if the real expression E, after promotion, has a
- signed or floating type. */
+ signed or floating type. Do not evaluate E. */
#define EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
/* Minimum and maximum values for integer types and expressions. */
/* The width in bits of the integer type or expression T.
+ Do not evaluate T. T must not be a bit-field expression.
Padding bits are not supported; this is checked at compile-time below. */
#define TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT)
@@ -59,7 +60,7 @@
: ((((t) 1 << (TYPE_WIDTH (t) - 2)) - 1) * 2 + 1)))
/* The maximum and minimum values for the type of the expression E,
- after integer promotion. E should not have side effects. */
+ after integer promotion. E is not evaluated. */
#define _GL_INT_MINIMUM(e) \
(EXPR_SIGNED (e) \
? ~ _GL_SIGNED_INT_MAXIMUM (e) \
@@ -69,7 +70,7 @@
? _GL_SIGNED_INT_MAXIMUM (e) \
: _GL_INT_NEGATE_CONVERT (e, 1))
#define _GL_SIGNED_INT_MAXIMUM(e) \
- (((_GL_INT_CONVERT (e, 1) << (TYPE_WIDTH ((e) + 0) - 2)) - 1) * 2 + 1)
+ (((_GL_INT_CONVERT (e, 1) << (TYPE_WIDTH (+ (e)) - 2)) - 1) * 2 + 1)
/* Work around OpenVMS incompatibility with C99. */
#if !defined LLONG_MAX && defined __INT64_MAX
@@ -80,28 +81,12 @@
/* This include file assumes that signed types are two's complement without
padding bits; the above macros have undefined behavior otherwise.
If this is a problem for you, please let us know how to fix it for your host.
- As a sanity check, test the assumption for some signed types that
- <limits.h> bounds. */
-verify (TYPE_MINIMUM (signed char) == SCHAR_MIN);
-verify (TYPE_MAXIMUM (signed char) == SCHAR_MAX);
-verify (TYPE_MINIMUM (short int) == SHRT_MIN);
-verify (TYPE_MAXIMUM (short int) == SHRT_MAX);
-verify (TYPE_MINIMUM (int) == INT_MIN);
-verify (TYPE_MAXIMUM (int) == INT_MAX);
-verify (TYPE_MINIMUM (long int) == LONG_MIN);
-verify (TYPE_MAXIMUM (long int) == LONG_MAX);
-#ifdef LLONG_MAX
-verify (TYPE_MINIMUM (long long int) == LLONG_MIN);
-verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
-#endif
-/* Similarly, sanity-check one ISO/IEC TS 18661-1:2014 macro if defined. */
-#ifdef UINT_WIDTH
-verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
-#endif
+ This assumption is tested by the intprops-tests module. */
/* Does the __typeof__ keyword work? This could be done by
'configure', but for now it's easier to do it by hand. */
#if (2 <= __GNUC__ \
+ || (4 <= __clang_major__) \
|| (1210 <= __IBMC__ && defined __IBM__TYPEOF__) \
|| (0x5110 <= __SUNPRO_C && !__STDC__))
# define _GL_HAVE___TYPEOF__ 1
@@ -110,8 +95,9 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
#endif
/* Return 1 if the integer type or expression T might be signed. Return 0
- if it is definitely unsigned. This macro does not evaluate its argument,
- and expands to an integer constant expression. */
+ if it is definitely unsigned. T must not be a bit-field expression.
+ This macro does not evaluate its argument, and expands to an
+ integer constant expression. */
#if _GL_HAVE___TYPEOF__
# define _GL_SIGNED_TYPE_OR_EXPR(t) TYPE_SIGNED (__typeof__ (t))
#else
@@ -124,18 +110,20 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
/* Bound on length of the string representing an integer type or expression T.
+ T must not be a bit-field expression.
+
Subtract 1 for the sign bit if T is signed, and then add 1 more for
a minus sign if needed.
- Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is
- signed, this macro may overestimate the true bound by one byte when
+ Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 1 when its argument is
+ unsigned, this macro may overestimate the true bound by one byte when
applied to unsigned types of size 2, 4, 16, ... bytes. */
#define INT_STRLEN_BOUND(t) \
(INT_BITS_STRLEN_BOUND (TYPE_WIDTH (t) - _GL_SIGNED_TYPE_OR_EXPR (t)) \
+ _GL_SIGNED_TYPE_OR_EXPR (t))
/* Bound on buffer size needed to represent an integer type or expression T,
- including the terminating null. */
+ including the terminating null. T must not be a bit-field expression. */
#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
@@ -197,7 +185,7 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
See above for restrictions. Avoid && and || as they tickle
bugs in Sun C 5.11 2010/08/13 and other compilers; see
- <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>. */
+ <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00401.html>. */
#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
((b) < 0 \
? ((a) < 0 \
@@ -236,11 +224,39 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
? (a) < (min) >> (b) \
: (max) >> (b) < (a))
-/* True if __builtin_add_overflow (A, B, P) works when P is non-null. */
-#define _GL_HAS_BUILTIN_OVERFLOW (5 <= __GNUC__)
+/* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow
+ (A, B, P) work when P is non-null. */
+/* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x,
+ see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98269>. */
+#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)
+#else
+# define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
+#endif
+
+/* True if __builtin_mul_overflow (A, B, P) works when P is non-null. */
+#ifdef __clang__
+/* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>. */
+# define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
+#else
+# define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW
+#endif
-/* True if __builtin_add_overflow_p (A, B, C) works. */
-#define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
+/* True if __builtin_add_overflow_p (A, B, C) works, and similarly for
+ __builtin_sub_overflow_p and __builtin_mul_overflow_p. */
+#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
/* The _GL*_OVERFLOW macros have the same restrictions as the
*_RANGE_OVERFLOW macros, except that they do not assume that operands
@@ -293,7 +309,9 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators
might not yield numerically correct answers due to arithmetic overflow.
- The INT_<op>_WRAPV macros also store the low-order bits of the answer.
+ The INT_<op>_WRAPV macros compute the low-order bits of the sum,
+ difference, and product of two C integers, and return 1 if these
+ low-order bits are not numerically correct.
These macros work correctly on all known practical hosts, and do not rely
on undefined behavior due to signed arithmetic overflow.
@@ -321,9 +339,11 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
arguments should not have side effects.
The WRAPV macros are not constant expressions. They support only
- +, binary -, and *. The result type must be signed.
+ +, binary -, and *. Because the WRAPV macros convert the result,
+ they report overflow in different circumstances than the OVERFLOW
+ macros do.
- These macros are tuned for their last argument being a constant.
+ These macros are tuned for their last input argument being a constant.
Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B,
A % B, and A << B would overflow, respectively. */
@@ -354,105 +374,257 @@ verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
Arguments should be free of side effects. */
#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \
op_result_overflow (a, b, \
- _GL_INT_MINIMUM (0 * (b) + (a)), \
- _GL_INT_MAXIMUM (0 * (b) + (a)))
+ _GL_INT_MINIMUM (_GL_INT_CONVERT (a, b)), \
+ _GL_INT_MAXIMUM (_GL_INT_CONVERT (a, b)))
/* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
Return 1 if the result overflows. See above for restrictions. */
-#define INT_ADD_WRAPV(a, b, r) \
- _GL_INT_OP_WRAPV (a, b, r, +, __builtin_add_overflow, INT_ADD_OVERFLOW)
-#define INT_SUBTRACT_WRAPV(a, b, r) \
- _GL_INT_OP_WRAPV (a, b, r, -, __builtin_sub_overflow, INT_SUBTRACT_OVERFLOW)
-#define INT_MULTIPLY_WRAPV(a, b, r) \
- _GL_INT_OP_WRAPV (a, b, r, *, __builtin_mul_overflow, INT_MULTIPLY_OVERFLOW)
+#if _GL_HAS_BUILTIN_ADD_OVERFLOW
+# define INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r)
+# define INT_SUBTRACT_WRAPV(a, b, r) __builtin_sub_overflow (a, b, r)
+#else
+# define INT_ADD_WRAPV(a, b, r) \
+ _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW)
+# define INT_SUBTRACT_WRAPV(a, b, r) \
+ _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__)) \
+ && !defined __ICC)
+# define INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r)
+# else
+ /* Work around GCC bug 91450. */
+# define INT_MULTIPLY_WRAPV(a, b, r) \
+ ((!_GL_SIGNED_TYPE_OR_EXPR (*(r)) && EXPR_SIGNED (a) && EXPR_SIGNED (b) \
+ && _GL_INT_MULTIPLY_RANGE_OVERFLOW (a, b, 0, (__typeof__ (*(r))) -1)) \
+ ? ((void) __builtin_mul_overflow (a, b, r), 1) \
+ : __builtin_mul_overflow (a, b, r))
+# endif
+#else
+# define INT_MULTIPLY_WRAPV(a, b, r) \
+ _GL_INT_OP_WRAPV (a, b, r, *, _GL_INT_MULTIPLY_RANGE_OVERFLOW)
+#endif
/* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
https://llvm.org/bugs/show_bug.cgi?id=25390
For now, assume all versions of GCC-like compilers generate bogus
- warnings for _Generic. This matters only for older compilers that
- lack __builtin_add_overflow. */
-#if __GNUC__
+ warnings for _Generic. This matters only for compilers that
+ lack relevant builtins. */
+#if __GNUC__ || defined __clang__
# define _GL__GENERIC_BOGUS 1
#else
# define _GL__GENERIC_BOGUS 0
#endif
/* Store the low-order bits of A <op> B into *R, where OP specifies
- the operation. BUILTIN is the builtin operation, and OVERFLOW the
- overflow predicate. Return 1 if the result overflows. See above
- for restrictions. */
-#if _GL_HAS_BUILTIN_OVERFLOW
-# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) builtin (a, b, r)
-#elif 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
-# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
+ the operation and OVERFLOW the overflow predicate. Return 1 if the
+ result overflows. See above for restrictions. */
+#if 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
+# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
(_Generic \
(*(r), \
signed char: \
- _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
signed char, SCHAR_MIN, SCHAR_MAX), \
+ unsigned char: \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned char, 0, UCHAR_MAX), \
short int: \
- _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
short int, SHRT_MIN, SHRT_MAX), \
+ unsigned short int: \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned short int, 0, USHRT_MAX), \
int: \
_GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
int, INT_MIN, INT_MAX), \
+ unsigned int: \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned int, 0, UINT_MAX), \
long int: \
_GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
long int, LONG_MIN, LONG_MAX), \
+ unsigned long int: \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
+ unsigned long int, 0, ULONG_MAX), \
long long int: \
_GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
- long long int, LLONG_MIN, LLONG_MAX)))
+ long long int, LLONG_MIN, LLONG_MAX), \
+ unsigned long long int: \
+ _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
+ unsigned long long int, 0, ULLONG_MAX)))
#else
-# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
+/* Store the low-order bits of A <op> B into *R, where OP specifies
+ the operation and OVERFLOW the overflow predicate. If *R is
+ signed, its type is ST with bounds SMIN..SMAX; otherwise its type
+ is UT with bounds U..UMAX. ST and UT are narrower than int.
+ Return 1 if the result overflows. See above for restrictions. */
+# if _GL_HAVE___TYPEOF__
+# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \
+ (TYPE_SIGNED (__typeof__ (*(r))) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, st, smin, smax) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, ut, 0, umax))
+# else
+# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \
+ (overflow (a, b, smin, smax) \
+ ? (overflow (a, b, 0, umax) \
+ ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 1) \
+ : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) < 0) \
+ : (overflow (a, b, 0, umax) \
+ ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) >= 0 \
+ : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 0)))
+# endif
+
+# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \
(sizeof *(r) == sizeof (signed char) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
- signed char, SCHAR_MIN, SCHAR_MAX) \
+ ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \
+ signed char, SCHAR_MIN, SCHAR_MAX, \
+ unsigned char, UCHAR_MAX) \
: sizeof *(r) == sizeof (short int) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
- short int, SHRT_MIN, SHRT_MAX) \
+ ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \
+ short int, SHRT_MIN, SHRT_MAX, \
+ unsigned short int, USHRT_MAX) \
: sizeof *(r) == sizeof (int) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
- int, INT_MIN, INT_MAX) \
+ ? (EXPR_SIGNED (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ int, INT_MIN, INT_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
+ unsigned int, 0, UINT_MAX)) \
: _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow))
# ifdef LLONG_MAX
# define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
(sizeof *(r) == sizeof (long int) \
- ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
- long int, LONG_MIN, LONG_MAX) \
- : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
- long long int, LLONG_MIN, LLONG_MAX))
+ ? (EXPR_SIGNED (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
+ long int, LONG_MIN, LONG_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
+ unsigned long int, 0, ULONG_MAX)) \
+ : (EXPR_SIGNED (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
+ long long int, LLONG_MIN, LLONG_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
+ unsigned long long int, 0, ULLONG_MAX)))
# else
# define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
- _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
- long int, LONG_MIN, LONG_MAX)
+ (EXPR_SIGNED (*(r)) \
+ ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
+ long int, LONG_MIN, LONG_MAX) \
+ : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
+ unsigned long int, 0, ULONG_MAX))
# endif
#endif
/* Store the low-order bits of A <op> B into *R, where the operation
is given by OP. Use the unsigned type UT for calculation to avoid
- overflow problems. *R's type is T, with extremal values TMIN and
- TMAX. T must be a signed integer type. Return 1 if the result
- overflows. */
+ overflow problems. *R's type is T, with extrema TMIN and TMAX.
+ T must be a signed integer type. Return 1 if the result overflows. */
#define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
- (sizeof ((a) op (b)) < sizeof (t) \
- ? _GL_INT_OP_CALC1 ((t) (a), (t) (b), r, op, overflow, ut, t, tmin, tmax) \
- : _GL_INT_OP_CALC1 (a, b, r, op, overflow, ut, t, tmin, tmax))
-#define _GL_INT_OP_CALC1(a, b, r, op, overflow, ut, t, tmin, tmax) \
- ((overflow (a, b) \
- || (EXPR_SIGNED ((a) op (b)) && ((a) op (b)) < (tmin)) \
- || (tmax) < ((a) op (b))) \
- ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 1) \
- : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 0))
-
-/* Return A <op> B, where the operation is given by OP. Use the
- unsigned type UT for calculation to avoid overflow problems.
- Convert the result to type T without overflow by subtracting TMIN
- from large values before converting, and adding it afterwards.
- Compilers can optimize all the operations except OP. */
-#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t, tmin, tmax) \
- (((ut) (a) op (ut) (b)) <= (tmax) \
- ? (t) ((ut) (a) op (ut) (b)) \
- : ((t) (((ut) (a) op (ut) (b)) - (tmin)) + (tmin)))
+ (overflow (a, b, tmin, tmax) \
+ ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \
+ : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0))
+
+/* Return the low-order bits of A <op> B, where the operation is given
+ by OP. Use the unsigned type UT for calculation to avoid undefined
+ behavior on signed integer overflow, and convert the result to type T.
+ UT is at least as wide as T and is no narrower than unsigned int,
+ T is two's complement, and there is no padding or trap representations.
+ Assume that converting UT to T yields the low-order bits, as is
+ done in all known two's-complement C compilers. E.g., see:
+ https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html
+
+ According to the C standard, converting UT to T yields an
+ implementation-defined result or signal for values outside T's
+ range. However, code that works around this theoretical problem
+ runs afoul of a compiler bug in Oracle Studio 12.3 x86. See:
+ https://lists.gnu.org/r/bug-gnulib/2017-04/msg00049.html
+ As the compiler bug is real, don't try to work around the
+ theoretical problem. */
+
+#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \
+ ((t) ((ut) (a) op (ut) (b)))
+
+/* Return true if the numeric values A + B, A - B, A * B fall outside
+ the range TMIN..TMAX. Arguments should be integer expressions
+ without side effects. TMIN should be signed and nonpositive.
+ TMAX should be positive, and should be signed unless TMIN is zero. */
+#define _GL_INT_ADD_RANGE_OVERFLOW(a, b, tmin, tmax) \
+ ((b) < 0 \
+ ? (((tmin) \
+ ? ((EXPR_SIGNED (_GL_INT_CONVERT (a, (tmin) - (b))) || (b) < (tmin)) \
+ && (a) < (tmin) - (b)) \
+ : (a) <= -1 - (b)) \
+ || ((EXPR_SIGNED (a) ? 0 <= (a) : (tmax) < (a)) && (tmax) < (a) + (b))) \
+ : (a) < 0 \
+ ? (((tmin) \
+ ? ((EXPR_SIGNED (_GL_INT_CONVERT (b, (tmin) - (a))) || (a) < (tmin)) \
+ && (b) < (tmin) - (a)) \
+ : (b) <= -1 - (a)) \
+ || ((EXPR_SIGNED (_GL_INT_CONVERT (a, b)) || (tmax) < (b)) \
+ && (tmax) < (a) + (b))) \
+ : (tmax) < (b) || (tmax) - (b) < (a))
+#define _GL_INT_SUBTRACT_RANGE_OVERFLOW(a, b, tmin, tmax) \
+ (((a) < 0) == ((b) < 0) \
+ ? ((a) < (b) \
+ ? !(tmin) || -1 - (tmin) < (b) - (a) - 1 \
+ : (tmax) < (a) - (b)) \
+ : (a) < 0 \
+ ? ((!EXPR_SIGNED (_GL_INT_CONVERT ((a) - (tmin), b)) && (a) - (tmin) < 0) \
+ || (a) - (tmin) < (b)) \
+ : ((! (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
+ && EXPR_SIGNED (_GL_INT_CONVERT ((tmax) + (b), a))) \
+ && (tmax) <= -1 - (b)) \
+ || (tmax) + (b) < (a)))
+#define _GL_INT_MULTIPLY_RANGE_OVERFLOW(a, b, tmin, tmax) \
+ ((b) < 0 \
+ ? ((a) < 0 \
+ ? (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \
+ ? (a) < (tmax) / (b) \
+ : ((INT_NEGATE_OVERFLOW (b) \
+ ? _GL_INT_CONVERT (b, tmax) >> (TYPE_WIDTH (+ (b)) - 1) \
+ : (tmax) / -(b)) \
+ <= -1 - (a))) \
+ : INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (b, tmin)) && (b) == -1 \
+ ? (EXPR_SIGNED (a) \
+ ? 0 < (a) + (tmin) \
+ : 0 < (a) && -1 - (tmin) < (a) - 1) \
+ : (tmin) / (b) < (a)) \
+ : (b) == 0 \
+ ? 0 \
+ : ((a) < 0 \
+ ? (INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (a, tmin)) && (a) == -1 \
+ ? (EXPR_SIGNED (b) ? 0 < (b) + (tmin) : -1 - (tmin) < (b) - 1) \
+ : (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 */