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short-circuit overflow protection for M1 Mac clang (#827)

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xref scipy/scipy#14901

Splits single if statement into two to avoid apparent clang short-circuit bug on M1 Mac platforms.

Co-authored-by: Matt Borland <matt@mattborland.com>
This commit is contained in:
Nicholas McKibben 2022-10-12 15:03:13 -07:00 committed by GitHub
parent 2a07116411
commit 7ad016f34b
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 44 additions and 3 deletions
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15
include/boost/math/special_functions/detail/igamma_inverse.hpp
View File

@ -362,10 +362,19 @@ struct gamma_p_inverse_func
T f2;
T div = (a - x - 1) / x;
f2 = f1;
if((fabs(div) > 1) && (tools::max_value<T>() / fabs(div) < f2))
if(fabs(div) > 1)
{
// overflow:
f2 = -tools::max_value<T>() / 2;
// split if statement to address M1 mac clang bug;
// see issue 826
if (tools::max_value<T>() / fabs(div) < f2)
{
// overflow:
f2 = -tools::max_value<T>() / 2;
}
else
{
f2 *= div;
}
}
else
{

1
test/Jamfile.v2
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@ -166,6 +166,7 @@ test-suite special_fun :
[ run powm1_sqrtp1m1_test.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework ]
[ run git_issue_705.cpp ../../test/build//boost_unit_test_framework ]
[ run git_issue_810.cpp ../../test/build//boost_unit_test_framework ]
[ run git_issue_826.cpp ../../test/build//boost_unit_test_framework ]
[ run special_functions_test.cpp ../../test/build//boost_unit_test_framework ]
[ run test_airy.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework ]
[ run test_bessel_j.cpp test_instances//test_instances pch_light ../../test/build//boost_unit_test_framework ]

31
test/git_issue_826.cpp Normal file
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@ -0,0 +1,31 @@
// Copyright Nicholas McKibben, 2022
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <cfenv>
#include <iostream>
#include <boost/math/distributions/beta.hpp>
#include "math_unit_test.hpp"
#pragma STDC FENV_ACCESS ON
int main() {
constexpr double q {0.999995};
constexpr double a {2};
constexpr double b {99999};
std::feclearexcept(FE_ALL_EXCEPT);
boost::math::beta_distribution<double> d {a, b};
const auto ans = boost::math::quantile(d, q);
if(std::fetestexcept(FE_OVERFLOW)) {
std::cout << "overflow reported" << std::endl;
} else {
std::cout << "overflow not reported" << std::endl;
}
std::cout << std::setprecision(16) << "Ans is: " << ans << std::endl;
return 0;
CHECK_ULP_CLOSE(ans, 0.000149761910560502, 1);
}
// overflow reported
// Ans is: 0.000149761910560502