87 lines
2.8 KiB
C++
87 lines
2.8 KiB
C++
//===-- Unittests for x86 long double -------------------------------------===//
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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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#include "src/__support/FPUtil/FPBits.h"
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#include "utils/UnitTest/Test.h"
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#include <math.h>
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using FPBits = __llvm_libc::fputil::FPBits<long double>;
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TEST(X86LongDoubleTest, is_nan) {
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// In the nan checks below, we use the macro isnan from math.h to ensure that
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// a number is actually a NaN. The isnan macro resolves to the compiler
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// builtin function. Hence, matching LLVM-libc's notion of NaN with the
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// isnan result ensures that LLVM-libc's behavior matches the compiler's
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// behavior.
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FPBits bits(0.0l);
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bits.exponent = FPBits::MAX_EXPONENT;
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for (unsigned int i = 0; i < 1000000; ++i) {
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// If exponent has the max value and the implicit bit is 0,
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// then the number is a NaN for all values of mantissa.
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bits.mantissa = i;
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long double nan = bits;
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ASSERT_NE(isnan(nan), 0);
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ASSERT_TRUE(bits.is_nan());
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}
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bits.implicitBit = 1;
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for (unsigned int i = 1; i < 1000000; ++i) {
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// If exponent has the max value and the implicit bit is 1,
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// then the number is a NaN for all non-zero values of mantissa.
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// Note the initial value of |i| of 1 to avoid a zero mantissa.
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bits.mantissa = i;
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long double nan = bits;
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ASSERT_NE(isnan(nan), 0);
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ASSERT_TRUE(bits.is_nan());
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}
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bits.exponent = 1;
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bits.implicitBit = 0;
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for (unsigned int i = 0; i < 1000000; ++i) {
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// If exponent is non-zero and also not max, and the implicit bit is 0,
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// then the number is a NaN for all values of mantissa.
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bits.mantissa = i;
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long double nan = bits;
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ASSERT_NE(isnan(nan), 0);
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ASSERT_TRUE(bits.is_nan());
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}
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bits.exponent = 1;
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bits.implicitBit = 1;
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for (unsigned int i = 0; i < 1000000; ++i) {
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// If exponent is non-zero and also not max, and the implicit bit is 1,
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// then the number is normal value for all values of mantissa.
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bits.mantissa = i;
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long double valid = bits;
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ASSERT_EQ(isnan(valid), 0);
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ASSERT_FALSE(bits.is_nan());
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}
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bits.exponent = 0;
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bits.implicitBit = 1;
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for (unsigned int i = 0; i < 1000000; ++i) {
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// If exponent is zero, then the number is a valid but denormal value.
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bits.mantissa = i;
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long double valid = bits;
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ASSERT_EQ(isnan(valid), 0);
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ASSERT_FALSE(bits.is_nan());
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}
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bits.exponent = 0;
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bits.implicitBit = 0;
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for (unsigned int i = 0; i < 1000000; ++i) {
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// If exponent is zero, then the number is a valid but denormal value.
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bits.mantissa = i;
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long double valid = bits;
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ASSERT_EQ(isnan(valid), 0);
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ASSERT_FALSE(bits.is_nan());
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}
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}
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