| 1 | //===-- Unittests for x86 long double -------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #include "src/__support/FPUtil/FPBits.h" |
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| 10 | #include "test/UnitTest/Test.h" |
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| 11 | |
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| 12 | #include "hdr/math_macros.h" |
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| 13 | |
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| 14 | using FPBits = LIBC_NAMESPACE::fputil::FPBits<long double>; |
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| 15 | |
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| 16 | TEST(LlvmLibcX86LongDoubleTest, is_nan) { |
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| 17 | // In the nan checks below, we use the macro isnan from math.h to ensure that |
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| 18 | // a number is actually a NaN. The isnan macro resolves to the compiler |
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| 19 | // builtin function. Hence, matching LLVM-libc's notion of NaN with the |
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| 20 | // isnan result ensures that LLVM-libc's behavior matches the compiler's |
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| 21 | // behavior. |
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| 22 | constexpr uint32_t COUNT = 100'000; |
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| 23 | |
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| 24 | FPBits bits(0.0l); |
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| 25 | bits.set_biased_exponent(FPBits::MAX_BIASED_EXPONENT); |
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| 26 | for (unsigned int i = 0; i < COUNT; ++i) { |
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| 27 | // If exponent has the max value and the implicit bit is 0, |
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| 28 | // then the number is a NaN for all values of mantissa. |
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| 29 | bits.set_mantissa(i); |
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| 30 | ASSERT_TRUE(bits.is_nan()); |
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| 31 | } |
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| 32 | |
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| 33 | bits.set_implicit_bit(1); |
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| 34 | for (unsigned int i = 1; i < COUNT; ++i) { |
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| 35 | // If exponent has the max value and the implicit bit is 1, |
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| 36 | // then the number is a NaN for all non-zero values of mantissa. |
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| 37 | // Note the initial value of |i| of 1 to avoid a zero mantissa. |
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| 38 | bits.set_mantissa(i); |
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| 39 | ASSERT_TRUE(bits.is_nan()); |
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| 40 | } |
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| 41 | |
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| 42 | bits.set_biased_exponent(1); |
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| 43 | bits.set_implicit_bit(0); |
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| 44 | for (unsigned int i = 0; i < COUNT; ++i) { |
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| 45 | // If exponent is non-zero and also not max, and the implicit bit is 0, |
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| 46 | // then the number is a NaN for all values of mantissa. |
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| 47 | bits.set_mantissa(i); |
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| 48 | ASSERT_TRUE(bits.is_nan()); |
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| 49 | } |
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| 50 | |
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| 51 | bits.set_biased_exponent(1); |
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| 52 | bits.set_implicit_bit(1); |
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| 53 | for (unsigned int i = 0; i < COUNT; ++i) { |
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| 54 | // If exponent is non-zero and also not max, and the implicit bit is 1, |
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| 55 | // then the number is normal value for all values of mantissa. |
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| 56 | bits.set_mantissa(i); |
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| 57 | ASSERT_FALSE(bits.is_nan()); |
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| 58 | } |
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| 59 | |
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| 60 | bits.set_biased_exponent(0); |
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| 61 | bits.set_implicit_bit(1); |
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| 62 | for (unsigned int i = 0; i < COUNT; ++i) { |
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| 63 | // If exponent is zero, then the number is a valid but denormal value. |
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| 64 | bits.set_mantissa(i); |
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| 65 | ASSERT_FALSE(bits.is_nan()); |
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| 66 | } |
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| 67 | |
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| 68 | bits.set_biased_exponent(0); |
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| 69 | bits.set_implicit_bit(0); |
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| 70 | for (unsigned int i = 0; i < COUNT; ++i) { |
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| 71 | // If exponent is zero, then the number is a valid but denormal value. |
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| 72 | bits.set_mantissa(i); |
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| 73 | ASSERT_FALSE(bits.is_nan()); |
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| 74 | } |
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| 75 | } |
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| 76 | |
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