If the span of the range R produced by uniform bit generator U passed to
generate_canonical is not power of two, we need to use algorithm that
requires computing power R^k that is greater than 2^d, where d is number
of digits in mantissa of _RealT. Previously we have used an integer type
that is has twice as many digits as d. This lead to situation that for
standard engines that produced such range (like std::minstd_rand0,
std::minstd_rand, std::ranlux24, ....) 256bit integer support was
required for 128bit floats. However, in this cases R^4 provides more
than d bits of precision, while requiring 124 bits.
We overestimate the number of required bits, by computing a value
l * bit_width(R) (log2(R) + 1), where l is value such that log2(R) * l >= d.
As R >= 2^log2(R), then R^l >= (2^log2(R))^l == 2^(log(R) * l) >= 2^d,
so k+1 >= l >= k. In consequence R^k is smaller R^l which require at most
l * bit_width(R). This is an overestimate, but difference should not be
higher than l bits.
We replace __gen_can_pow and __gen_can_rng_calls_needed with
__gen_canon_log(v, b), which computes the largest power of b that fits into v.
As such a number is smaller than v, the result will always fit in it's type.
Both the logarithm and the power value are returned using
__gen_canon_log_res struct.
libstdc++-v3/ChangeLog:
* include/bits/random.h (__rand_uint128::operator>)
(__rand_uint128::operator>=): Define.
* include/bits/random.tcc (__generate_canonical_pow2):
Adjust for use of __rand_uint128 in C++11.
(__gen_can_pow, __gen_can_rng_calls_needed): Replace with
__gen_canon_log.
(__gen_canon_log_res, __gen_canon_log): Define.
(__generate_canonical_any): Reworked how _UInt is determined.
* testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon_eng.cc:
New test.
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
Make use of __detail::_Select_uint_least_t<d>::type for
std::generate_canonical, so that we choose an appropriately sized
integer based on the number of bits needed, and so we have a 128-bit
integer type even on 32-bit targets (via the new __rand_uint128 class).
libstdc++-v3/ChangeLog:
* include/bits/random.tcc (__generate_canonical_pow2): Adjust
comments. Remove _UInt template parameter and define it in the
body using _Select_uint_least_t<__d>. Remove popcount call for
getting the width of the _UInt type. Cast floating-point
literal to _RealT.
(__generate_canonical_any): Remove _UInt template parameter and
define it in the body using _Select_uint_least_t<__d * 2>. Use
direct-initialization for _UInt variables. Cast floating-point
literal to _RealT.
(generate_canonical): Remove unused typedef. Remove constexpr-if
branches and remove unsigned type from template argument lists.
Co-authored-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Nathan Myers <nmyers@redhat.com>
This moves the __detail::_Select_uint_least_t<N>::type class to
namespace scope and extends it with more 128-bit arithmetic operations,
implemented in terms of uint64_t.
Now std::philox_engine can use _Select_uint_least_t<w*2>::type instead
of __uint128_t, so that it works on targets without 128-bit integers.
This also means that targets that do support __uint128_t only use it
when actually necessary, so that we use uint64_t when generating a
32-bit result (e.g. with std::philox4x32).
libstdc++-v3/ChangeLog:
* include/bits/random.h [!__SIZEOF_INT128__] (__rand_uint128):
Refactor and rename _Select_uint_least_t<128>::type to a new
class. Make all members constexpr. Add new member functions for
additional arithmetic and bitwise operations, and comparisons.
(__detail::_Select_uint_least_t<>::type): Define as an alias of
__rand_uint128.
* include/bits/random.tcc (philox_engine::_M_mulhi): Use
_Select_uint_least_t<w*2>::type instead of __uint128_t.
(philox_engine::_M_transition): Likewise.
* include/bits/version.def (philox_engine): Remove extra_cond.
* include/bits/version.h: Regenerate.
* testsuite/26_numerics/random/philox4x32.cc: Remove
dg-require-cpp-feature-test directive.
* testsuite/26_numerics/random/philox4x64.cc: Likewise.
* testsuite/26_numerics/random/philox_engine/cons/copy.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/cons/default.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/cons/seed.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/operators/equal.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/operators/serialize.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/requirements/constants.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/requirements/typedefs.cc:
Likewise.
Co-authored-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
This ensures that the new definition of std::generate_canonical has a
different mangled name from the old one, so that TUs compiled with GCC
16 will be sure to use the new definition, even if the linker also sees
a symbol instantiated from the old definition. We use the same _V2
inline namespace as used elsewhere (std::_V2::condition_variable,
std::_V2::__rotate, and std::chrono::_V2::system_clock), and use a macro
to add it conditionally so that it's not used for the ABI-unstable
gnu-versioned-namespace configuration.
We can simplify the 26_numerics/random/pr60037-neg.cc test to only use
one dg-error without a line number, so that it matches any of the three
relevant static_assert failures for this test: the one from _Adaptor in
<bits/random.h> and the ones from the new and old definitions of
std::generate_canonical in <bits/random.tcc>. Without this change, the
line number for the dg-error matching the <bits/random.tcc> error
depends on the _GLIBCXX_USE_OLD_GENERATE_CANONICAL macro, which is
awkward to depend on in the test (because DejaGnu sees all dg-error
directives, it doesn't care if they're guarded by #ifdef preprocessor
checks).
libstdc++-v3/ChangeLog:
* include/bits/random.h [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL]
(generate_canonical): Use inline namespace _V2.
* include/bits/random.tcc [!_GLIBCXX_USE_OLD_GENERATE_CANONICAL]
(generate_canonical): Likewise.
* testsuite/26_numerics/random/pr60037-neg.cc: Remove lineno so
that one dg-error matches both diagnostics.
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
The r16-6177-g866bc8a9214b1d introduced type-constraint on _Urbg template
parameter in __glibcxx_concepts, with was inconsistent with declaration in
bits/random.h and definition in bits/random.tcc causing the missing symbol
errors in tests.
Furthermore, this made the mangled name of generate_canonical in C++20
mode different from older standard and previous versions of GCC.
libstdc++-v3/ChangeLog:
* include/bits/random.tcc (generate_canonical)
[!_GLIBCXX_USE_OLD_GENERATE_CANONICAL]: Use static_assert
instead of type-constraint on template parameter.
* testsuite/26_numerics/random/pr60037-neg.cc: Updated line
of error.
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/random.tcc (generate_canonical): Update
error message to match pre-existing one in random.h.
* testsuite/26_numerics/random/pr60037-neg.cc: Updated
line for error message.
On x86_64-linux I see
On x86_64-linux
FAIL: 17_intro/headers/c++1998/all_pedantic_errors.cc -std=gnu++17 (test for excess errors)
Excess errors:
/home/jakub/src/gcc/obj20/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/random.tcc:3681: error: ISO C++ does not support '__int128' for 'type name' [-Wpedantic]
/home/jakub/src/gcc/obj20/x86_64-pc-linux-gnu/libstdc++-v3/include/bits/random.tcc:3698: error: ISO C++ does not support '__int128' for 'type name' [-Wpedantic]
This fixes it by adding __extension__.
2025-12-17 Jakub Jelinek <jakub@redhat.com>
* include/bits/random.tcc (std::generate_canonical): Use
__extension__ before __generate_canonical_{pow2,any} calls with
unsigned __int128 template arguments.
Implement P0952R2 "A new specification for
std::generate_canonical", fixing issue LWG 2524.
It has us start over, using new entropy, if the naïve generation
of a value in [0..1) comes up equal to 1.0, which occurs too
rarely for the change to measurably affect performance, but
does affect the number of calls to the underlying random bit
generator.
The old implementation is preserved, guarded by preprocessor
macro _GLIBCXX_USE_OLD_GENERATE_CANONICAL, for use where behavior
exactly matching previous runs is required.
The fix is extended to all of C++11 to 26. The public function
dispatches to variations optimized for requested bit depth `d`,
using minimal integer sizes for exact intermediate calculations.
It is faster than the old implementation, which computed a
floating-point logarithm, and performs all intermediate
calculations on integer types. It does not allow the IEEE half-
precision type `float16_t`, as its range is not large enough to
represent intermediate integer values specified, but does allow
`bfloat16_t`.
This implementation varies from the Standard in retaining in the
output mantissa as much as possible of the entropy obtained from
the provided random bit generator, not just the leading `d` bits
of randomness as specified, and in permitting use on floating
point types beyond float, double, and long double. The macro
_GLIBCXX_GENERATE_CANONICAL_STRICT may be defined to obtain the
exact Standard behavior.
This patch also adds tests for statistical properties, and adds
new static asserts on template argument requirements where
supported. It adds tests using non-optimal RNGs that yield
values 0..999999 and 0..0x7ffffffe.
A test for the case addressed in LWG 2524 already appeared in
64351.cc. This change amounts to a different resolution for
bugzilla PR64351 and LWG 2524.
libstdc++-v3/ChangeLog:
PR libstdc++/119739
* include/bits/random.tcc: Add generate_canonical impl for C++26.
* testsuite/26_numerics/random/uniform_real_distribution/operators/64351.cc:
Adapt test for both pre- and post- C++26.
* testsuite/26_numerics/random/uniform_real_distribution/operators/gencanon.cc:
Test for float and double from 32-bit RNG, including 1.0 do-over.
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
This fixes a 'for' loop in std::piecewise_linear_distribution that
increments two iterators with a comma operator between them, making it
vulnerable to evil overloads of the comma operator.
It also changes a 'for' loop used by some other distributions, even
though those are only used with std::vector<double>::iterator and so
won't find any overloaded commas.
libstdc++-v3/ChangeLog:
PR libstdc++/122062
* include/bits/random.tcc (__detail::__normalize): Use void cast
for operands of comma operator.
(piecewise_linear_distribution): Likewise.
* testsuite/26_numerics/random/piecewise_linear_distribution/cons/122062.cc:
New test.
Reviewed-by: Tomasz Kamiński <tkaminsk@redhat.com>
Reviewed-by: Hewill Kang <hewillk@gmail.com>
libstdc++-v3/ChangeLog:
* include/bits/random.h: Include <bits/ios_base.h> instead of
<iomanip>. Change preprocessor checks to use internal feature
test macro.
(philox_engine): Reword doxygen comments. Use typename instead
of class in template parameter lists. Reformat and adjust
whitespace.
(philox_engine::_If_seed_seq): Replace alias template with
__is_seed_seq variable template.
(philox_engine::philox_engine(result_type)): Define inline.
(philox_engine::seed(result_type), philox_engine::set_counter)
(philox_engine::operator(), philox_engine::discard): Likewise.
(operator==): Define as defaulted.
(operator<<): Reuse widened char.
* include/bits/random.tcc: Reformat and adjust whitespace.
(philox_engine::_M_philox): Use std::array copy constructor and
std::array::fill instead of looping.
* testsuite/26_numerics/random/philox4x32.cc: Gate test on
feature test macro. Add static_assert to check typedef.
* testsuite/26_numerics/random/philox4x64.cc: Likewise.
* testsuite/26_numerics/random/philox_engine/cons/copy.cc: Add
VERIFY assertions to check copies are equal. Test different
seeds.
* testsuite/26_numerics/random/philox_engine/cons/default.cc:
Add VERIFY assertions to check construction results.
* testsuite/26_numerics/random/philox_engine/cons/seed.cc:
Likewise.
* testsuite/26_numerics/random/philox_engine/operators/equal.cc:
Also test inequality.
* testsuite/26_numerics/random/philox_engine/operators/serialize.cc:
Remove redundant include and return.
* testsuite/26_numerics/random/philox_engine/requirements/constants.cc:
Check values of all constants.
* testsuite/26_numerics/random/philox_engine/requirements/typedefs.cc:
Check typedefs are correct.
* testsuite/26_numerics/random/philox_engine/cons/119794.cc:
Removed.
* testsuite/26_numerics/random/philox_engine/cons/seed_seq.cc:
Removed.
* testsuite/26_numerics/random/philox_engine/operators/inequal.cc:
Removed.
* testsuite/26_numerics/random/philox_engine/requirements/constexpr_data.cc:
Removed.
* testsuite/26_numerics/random/philox_engine/requirements/constexpr_functions.cc:
Removed.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
Conforms with errata LWG4143, LWG4153 for Philox Engine.
PR libstdc++/119794
libstdc++-v3/ChangeLog:
* include/bits/random.h (philox_engine): Define.
* include/bits/random.tcc (philox_engine): Define member
functions.
* include/bits/version.def (philox_engine): New macro.
* include/bits/version.h: Regenerated.
* include/std/random: Define __glibcxx_want_philox_engine and
include <bits/version.h>.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
* testsuite/26_numerics/random/philox4x32.cc: New test.
* testsuite/26_numerics/random/philox4x64.cc: New test.
* testsuite/26_numerics/random/philox_engine/cons/119794.cc: New test.
* testsuite/26_numerics/random/philox_engine/cons/copy.cc: New test.
* testsuite/26_numerics/random/philox_engine/cons/default.cc: New test.
* testsuite/26_numerics/random/philox_engine/cons/seed.cc: New test.
* testsuite/26_numerics/random/philox_engine/cons/seed_seq.cc: New test.
* testsuite/26_numerics/random/philox_engine/operators/equal.cc: New test.
* testsuite/26_numerics/random/philox_engine/operators/inequal.cc: New test.
* testsuite/26_numerics/random/philox_engine/operators/serialize.cc: New test.
* testsuite/26_numerics/random/philox_engine/requirements/constants.cc: New test.
* testsuite/26_numerics/random/philox_engine/requirements/constexpr_data.cc: New test.
* testsuite/26_numerics/random/philox_engine/requirements/constexpr_functions.cc: New test.
* testsuite/26_numerics/random/philox_engine/requirements/typedefs.cc: New test.
The multiplication (4 * _M_t * __1p) can wraparound to zero if _M_t is
unsigned and 4 * _M_t wraps to zero. The third operand has type double,
so do the second multiplication first, so that we aren't multiplying
integers.
libstdc++-v3/ChangeLog:
PR libstdc++/114359
* include/bits/random.tcc (binomial_distribution::param_type):
Ensure arithmetic is done as type double.
* testsuite/26_numerics/random/binomial_distribution/114359.cc: New test.
I implemented the resolution of LWG 3809 in r13-4364-ga64775a0edd469 but
it was recently noted in the MSVC STL github repo that the change causes
possible truncation for 64-bit seeds. Whether the truncation occurs (and
to what value) depends on the width of uint_least32_t which is not
portable, so the output of the PRNG for 64-bit seed values is no longer
the same as in C++20, and no longer portable across platforms.
That new issue was filed as LWG 4014. I proposed a new change which
reduces the seed by the LCG's modulus before the conversion to
uint_least32_t. This ensures that 64-bit seed values are consistently
reduced by the modulus before any truncation. This removes the
platform-dependent behaviour and restores the old behaviour for
std::subtract_with_carry_engine specializations using a 64-bit result
type (such as std::ranlux48_base).
libstdc++-v3/ChangeLog:
PR libstdc++/107466
* include/bits/random.tcc (subtract_with_carry_engine::seed):
Implement proposed resolution of LWG 4014.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
* testsuite/26_numerics/random/subtract_with_carry_engine/cons/lwg3809.cc:
Check for expected result of 64-bit engine with seed that
doesn't fit in 32-bits.
Similar to the three commits r14-908, r14-909 and r14-910, the
_GLIBCXX_USE_C99_MATH_TR1 macro is misleading when it is also used for
<cmath>, not only for <tr1/cmath> headers. It is also wrong, because the
configure checks for TR1 use -std=c++98 and a target might define the
C99 features for C++11 but not for C++98.
Add separate configure checks for the <math.h> functions using
-std=c++11 for the checks. Use the new macro defined by those checks in
the C++11-specific parts of <cmath>, and in <complex>, <random> etc.
The check that defines _GLIBCXX_NO_C99_ROUNDING_FUNCS is only needed for
the C++11 <cmath> checks, so remove that from GLIBCXX_CHECK_C99_TR1 and
only do it for GLIBCXX_ENABLE_C99.
libstdc++-v3/ChangeLog:
* acinclude.m4 (GLIBCXX_ENABLE_C99): Add checks for C99 math
functions and define _GLIBCXX_USE_C99_MATH_FUNCS. Move checks
for C99 rounding functions to here.
(GLIBCXX_CHECK_C99_TR1): Remove checks for C99 rounding
functions from here.
* config.h.in: Regenerate.
* configure: Regenerate.
* include/bits/random.h: Use _GLIBCXX_USE_C99_MATH_FUNCS instead
of _GLIBCXX_USE_C99_MATH_TR1.
* include/bits/random.tcc: Likewise.
* include/c_compatibility/math.h: Likewise.
* include/c_global/cmath: Likewise.
* include/ext/random: Likewise.
* include/ext/random.tcc: Likewise.
* include/std/complex: Likewise.
* testsuite/20_util/from_chars/4.cc: Likewise.
* testsuite/20_util/from_chars/8.cc: Likewise.
* testsuite/26_numerics/complex/proj.cc: Likewise.
* testsuite/26_numerics/headers/cmath/60401.cc: Likewise.
* testsuite/26_numerics/headers/cmath/types_std_c++0x.cc:
Likewise.
* testsuite/lib/libstdc++.exp (check_v3_target_cstdint):
Likewise.
* testsuite/util/testsuite_random.h: Likewise.
This implements the proposed resolution of LWG 3809, so that
std::subtract_with_carry_engine can be used with a 16-bit result_type.
Currently this produces a narrowing error when instantiating the
std::linear_congruential_engine to create the initial state. It also
truncates the default_seed constant when passing it as a result_type
argument.
Change the type of the constant to uint_least32_t and pass 0u when the
default_seed should be used.
libstdc++-v3/ChangeLog:
PR libstdc++/107466
* include/bits/random.h (subtract_with_carry_engine): Use 32-bit
type for default seed. Use 0u as default argument for
subtract_with_carry_engine(result_type) constructor and
seed(result_type) member function.
* include/bits/random.tcc (subtract_with_carry_engine): Use
32-bit type for default seed and engine used for initial state.
* testsuite/26_numerics/random/subtract_with_carry_engine/cons/lwg3809.cc:
New test.
This fixes a regression in std::normal_distribution deserialization that
caused the object to be left unchanged if the __state_avail value read
from the stream was false.
libstdc++-v3/ChangeLog:
PR libstdc++/105502
* include/bits/random.tcc
(operator>>(basic_istream<C,T>&, normal_distribution<R>&)):
Update state when __state_avail is false.
* testsuite/26_numerics/random/normal_distribution/operators/serialize.cc:
Check that deserialized object equals serialized one.
When std::seed_seq is constructed from random access iterators we can
detect the internal vector size in O(1). Reserving memory for elements
in such cases may avoid multiple memory allocations.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/random.tcc (seed_seq::seed_seq): Reserve capacity
if distance is O(1).
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
In C++17 the out-of-class definitions for static constexpr variables are
redundant, because they are implicitly inline. This change avoids
"redundant redeclaration" warnings from -Wsystem-headers -Wdeprecated.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/random.tcc (linear_congruential_engine): Do not
define static constexpr members when they are implicitly inline.
* include/std/ratio (ratio, __ratio_multiply, __ratio_divide)
(__ratio_add, __ratio_subtract): Likewise.
* include/std/type_traits (integral_constant): Likewise.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
This defines some new Doxygen groups for C++17 variable templates and
for the contents of <experimental/type_traits>. By documenting the group
as a whole and adding each template to a group we don't need to document
them individually.
Also mark more internals with "@cond undocumented" so that Doxygen
ignores them by default. Also make Doxygen process <experimental/simd>.
For some reason, many of the class templates in <type_traits> do not
appear in the "Metaprogramming" group. For example, add_cv,
remove_extent, and all the is_xxx_constructible and is_xxx_assignable
traits. For some reason, Doxygen doesn't include them in the group,
despite doing it correctly for other traits in the same header.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
PR libstdc++/101258
* doc/doxygen/user.cfg.in (INPUT): Add <experimental/simd>.
(COLS_IN_ALPHA_INDEX): Remove obsolete tag.
(PREDEFINED): Add/fix some more macros that need to be expanded.
* include/bits/random.h: Stop Doxygen from documenting internal
implementation details.
* include/bits/random.tcc: Likewise.
* include/bits/this_thread_sleep.h: Fix @file name.
* include/experimental/bits/simd.h: Add to Doxygen group. Do not
document internal implementation details.
* include/experimental/bits/simd_detail.h: Do not document
internal implementation details.
* include/experimental/simd: Define Doxygen groups.
* include/experimental/type_traits: Improve documentation for
the header file. Define groups. Use @since commands.
* include/std/scoped_allocator (scoped_allocator_adaptor): Move
declaration before undocumented region.
* include/std/type_traits (true_type, false_type): Use using
declaration instead of typedef.
(is_invocable_v, is_nothrow_invocable_v, is_invocable_r_v)
(is_nothrow_invocable_r_v): Move definitions next to other C++17
variable templates.
Do not document internal implementation details. Move misplaced
group-end command. Define group for variable templates.
* include/std/variant: Do not document internal implementation
details.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
Since C++17 the static members of the random number engines are
implicitly inline, so don't need definitions.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/random.tcc [__cpp_inline_variables]: Remove
redundant definitions of static constexpr member variables.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
This ensures that the std::seed_seq initializer-list constructor will
not be used for list-initialization unless the initializers in the list
are integers. This allows list-initialization syntax to be used with a
pair of pointers and for that to use the appropriate constructor.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/bits/random.h (seed_seq): Constrain initializer-list
constructor.
* include/bits/random.tcc (seed_seq): Add template parameter.
* testsuite/26_numerics/random/seed_seq/cons/default.cc: Check
for noexcept.
* testsuite/26_numerics/random/seed_seq/cons/initlist.cc: Check
constraints.
The transition algorithm for std::shuffle_order_engine uses long double
to ensure that the value (max() - min() + 1) can be accurately
represented, to avoid bias in the shuffling. However, when the base
engine's range is small enough we can avoid slower long double
arithmetic by using double. For example, long double is unnecessary for
any base engine returning 32-bit values.
This makes std::knuth_b::operator() about 15% faster on x86_64, and
probably even more on targets where long double uses soft-float.
libstdc++-v3/ChangeLog:
* include/bits/random.h (independent_bit_engine): Fix typo
in comment.
(shuffle_order_engine): Fix incorrect description in comment.
* include/bits/random.tcc (__representable_as_double
(__p1_representable_as_double): New helper functions.
(shuffle_order_engine::operator()): Use double for calculation
if (max() - min() + 1) is representable as double.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line number.
This ensures that intermediate results are done in uint32_t values,
meeting the requirement for operations to be done modulo 2^32.
If the target doesn't define __UINT32_TYPE__ then substitute uint32_t
with a class type that uses uint_least32_t and masks the value to
UINT32_MAX.
I've also split the first loop that goes from k=0 to k<m into three
loops, for k=0, [1,s] and [s+1,m). This avoids branching for those three
cases in the body of the loop, and also avoids the concerns in PR 94823
regarding the k-1 index when k==0.
libstdc++-v3/ChangeLog:
PR libstdc++/97311
* include/bits/random.tcc (seed_seq::generate): Use uint32_t for
calculations. Also split the first loop into three loops to
avoid branching on k on every iteration, resolving PR 94823.
* testsuite/26_numerics/random/seed_seq/97311.cc: New test.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-erro
line number.
These three distributions all require 0 < S where S is the sum of the
weights. When the sum is zero there's an undefined FP division by zero.
Add assertions to help users diagnose the problem.
libstdc++-v3/ChangeLog:
PR libstdc++/82584
* include/bits/random.tcc
(discrete_distribution::param_type::_M_initialize)
(piecewise_constant_distribution::param_type::_M_initialize)
(piecewise_linear_distribution::param_type::_M_initialize):
Add assertions for positive sums..
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error
line.
The deserialization functions for random number distributions fail to
check the stream state before using the extracted values. In some cases
this leads to using indeterminate values to resize a vector, and then
filling that vector with indeterminate values.
No values that affect control flow should be used without checking that a
good value was read from the stream.
Additionally, where reasonable to do so, defer modifying any state in
the distribution until all values have been successfully read, to avoid
modifying some of the distribution's parameters and leaving others
unchanged.
PR libstdc++/93205
* include/bits/random.h (operator>>): Check stream operation succeeds.
* include/bits/random.tcc (operator<<): Remove redundant __ostream_type
typedefs.
(operator>>): Remove redundant __istream_type typedefs. Check stream
operations succeed.
(__extract_params): New function to fill a vector from a stream.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error line.
From-SVN: r280061
Constrain constructors and member functions of random number engines so
that functions taking seed sequences can only be called with types that
meet the seed sequence requirements.
PR libstdc++/85749
* include/bits/random.h (__detail::__is_seed_seq): New SFINAE helper.
(linear_congruential_engine, mersenne_twister_engine)
(subtract_with_carry_engine, discard_block_engine)
(independent_bits_engine, shuffle_order_engine): Use __is_seed_seq to
constrain function templates taking seed sequences.
* include/bits/random.tcc (linear_congruential_engine::seed(_Sseq&))
(mersenne_twister_engine::seed(_Sseq&))
(subtract_with_carry_engine::seed(_Sseq&)): Change return types to
match declarations.
* include/ext/random (simd_fast_mersenne_twister_engine): Use
__is_seed_seq to constrain function templates taking seed sequences.
* include/ext/random.tcc (simd_fast_mersenne_twister_engine::seed):
Change return type to match declaration.
* testsuite/26_numerics/random/discard_block_engine/cons/seed_seq2.cc:
New.
* testsuite/26_numerics/random/independent_bits_engine/cons/
seed_seq2.cc: New.
* testsuite/26_numerics/random/linear_congruential_engine/cons/
seed_seq2.cc: New.
* testsuite/26_numerics/random/mersenne_twister_engine/cons/
seed_seq2.cc: New.
* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error lineno.
* testsuite/26_numerics/random/shuffle_order_engine/cons/seed_seq2.cc:
New.
* testsuite/26_numerics/random/subtract_with_carry_engine/cons/
seed_seq2.cc: New.
* testsuite/ext/random/simd_fast_mersenne_twister_engine/cons/
seed_seq2.cc: New.
From-SVN: r260263
2018-05-07 Edward Smith-Rowland <3dw4rd@verizon.net>
Moar PR libstdc++/80506
* include/bits/random.tcc (gamma_distribution::__generate_impl()):
Fix magic number used in loop condition.
Actually put the file in.
Don't know what my problem is today...
From-SVN: r260008
Jakub Jelinek