55b6136b3a
This is needed anytime we need to clamp an arbitrary floating point value to an integer type. Thanks to Eric Fiselier for the patch. Differential Revision: https://reviews.llvm.org/D66836 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@370891 91177308-0d34-0410-b5e6-96231b3b80d8 (cherry picked from commit c9ac8d533010d8915bcfdecab891fb451f71ce74) (cherry picked from commit 4561f55204960c0b3bc4594089ddcf56e5655cad) (cherry picked from commit f4471784fdb5799b9862febc385a26becfbe53b3) Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=994957 Bug: http://b/139690488 Change-Id: I3d402ed0237a2f5f934a5d368ca91304bfcd9ed0
91 lines
2.9 KiB
C++
91 lines
2.9 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// __clamp_to_integral<IntT>(RealT)
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// Test the conversion function that truncates floating point types to the
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// closest representable value for the specified integer type, or
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// numeric_limits<IntT>::max()/min() if the value isn't representable.
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#include <limits>
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#include <cassert>
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#include <cmath>
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template <class IntT>
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void test() {
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typedef std::numeric_limits<IntT> Lim;
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const bool MaxIsRepresentable = sizeof(IntT) < 8;
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const bool IsSigned = std::is_signed<IntT>::value;
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struct TestCase {
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double Input;
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IntT Expect;
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bool IsRepresentable;
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} TestCases[] = {
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{0, 0, true},
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{1, 1, true},
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{IsSigned ? static_cast<IntT>(-1) : 0,
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IsSigned ? static_cast<IntT>(-1) : 0, true},
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{Lim::lowest(), Lim::lowest(), true},
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{static_cast<double>(Lim::max()), Lim::max(), MaxIsRepresentable},
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{static_cast<double>(Lim::max()) + 1, Lim::max(), false},
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{static_cast<double>(Lim::max()) + 1024, Lim::max(), false},
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{nextafter(static_cast<double>(Lim::max()), INFINITY), Lim::max(), false},
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};
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for (TestCase TC : TestCases) {
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auto res = std::__clamp_to_integral<IntT>(TC.Input);
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assert(res == TC.Expect);
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if (TC.IsRepresentable) {
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auto other = static_cast<IntT>(std::trunc(TC.Input));
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assert(res == other);
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} else
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assert(res == Lim::min() || res == Lim::max());
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}
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}
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template <class IntT>
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void test_float() {
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typedef std::numeric_limits<IntT> Lim;
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const bool MaxIsRepresentable = sizeof(IntT) < 4;
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((void)MaxIsRepresentable);
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const bool IsSigned = std::is_signed<IntT>::value;
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struct TestCase {
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float Input;
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IntT Expect;
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bool IsRepresentable;
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} TestCases[] = {
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{0, 0, true},
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{1, 1, true},
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{IsSigned ? static_cast<IntT>(-1) : 0,
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IsSigned ? static_cast<IntT>(-1) : 0, true},
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{Lim::lowest(), Lim::lowest(), true},
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{static_cast<float>(Lim::max()), Lim::max(), MaxIsRepresentable },
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{nextafter(static_cast<float>(Lim::max()), INFINITY), Lim::max(), false},
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};
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for (TestCase TC : TestCases) {
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auto res = std::__clamp_to_integral<IntT>(TC.Input);
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assert(res == TC.Expect);
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if (TC.IsRepresentable) {
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auto other = static_cast<IntT>(std::trunc(TC.Input));
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assert(res == other);
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} else
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assert(res == Lim::min() || res == Lim::max());
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}
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}
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int main() {
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test<short>();
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test<unsigned short>();
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test<int>();
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test<unsigned>();
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test<long long>();
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test<unsigned long long>();
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test_float<short>();
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test_float<int>();
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test_float<long long>();
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}
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