1 //===-- Unittests for log2f -----------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/__support/FPUtil/FPBits.h"
10 #include "src/math/log2f.h"
11 #include "utils/MPFRWrapper/MPFRUtils.h"
12 #include "utils/UnitTest/FPMatcher.h"
13 #include "utils/UnitTest/Test.h"
14 #include <math.h>
15 
16 #include <errno.h>
17 #include <stdint.h>
18 
19 namespace mpfr = __llvm_libc::testing::mpfr;
20 
21 DECLARE_SPECIAL_CONSTANTS(float)
22 
23 TEST(LlvmLibcLog2fTest, SpecialNumbers) {
24   EXPECT_FP_EQ(aNaN, __llvm_libc::log2f(aNaN));
25   EXPECT_FP_EQ(inf, __llvm_libc::log2f(inf));
26   EXPECT_TRUE(FPBits(__llvm_libc::log2f(neg_inf)).is_nan());
27   EXPECT_FP_EQ(neg_inf, __llvm_libc::log2f(0.0f));
28   EXPECT_FP_EQ(neg_inf, __llvm_libc::log2f(-0.0f));
29   EXPECT_TRUE(FPBits(__llvm_libc::log2f(-1.0f)).is_nan());
30   EXPECT_FP_EQ(zero, __llvm_libc::log2f(1.0f));
31 }
32 
33 TEST(LlvmLibcLog2fTest, TrickyInputs) {
34   constexpr int N = 10;
35   constexpr uint32_t INPUTS[N] = {
36       0x3f7d57f5U, 0x3f7e3274U, 0x3f7ed848U, 0x3f7fd6ccU, 0x3f7fffffU,
37       0x3f80079bU, 0x3f81d0b5U, 0x3f82e602U, 0x3f83c98dU, 0x3f8cba39U};
38 
39   for (int i = 0; i < N; ++i) {
40     float x = float(FPBits(INPUTS[i]));
41     EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
42                                    __llvm_libc::log2f(x), 0.5);
43   }
44 }
45 
46 TEST(LlvmLibcLog2fTest, InFloatRange) {
47   constexpr uint32_t COUNT = 1000000;
48   constexpr uint32_t STEP = UINT32_MAX / COUNT;
49   for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
50     float x = float(FPBits(v));
51     if (isnan(x) || isinf(x))
52       continue;
53     errno = 0;
54     float result = __llvm_libc::log2f(x);
55     // If the computation resulted in an error or did not produce valid result
56     // in the single-precision floating point range, then ignore comparing with
57     // MPFR result as MPFR can still produce valid results because of its
58     // wider precision.
59     if (isnan(result) || isinf(result) || errno != 0)
60       continue;
61     ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
62                                    __llvm_libc::log2f(x), 0.5);
63   }
64 }
65