libc/test/src/__support/str_to_long_double_test.cpp

   1 //===-- Unittests for str_to_float<long double> ---------------------------===//
   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/macros/config.h"
  10 #include "str_to_fp_test.h"
  11
  12 #include "src/__support/integer_literals.h"
  13
  14 namespace LIBC_NAMESPACE_DECL {
  15
  16 using LlvmLibcStrToLongDblTest = LlvmLibcStrToFloatTest<long double>;
  17 using LIBC_NAMESPACE::operator""_u128;
  18
  19 #if defined(LIBC_TYPES_LONG_DOUBLE_IS_FLOAT64)
  20
  21 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat64AsLongDouble) {
  22   eisel_lemire_test(123, 0, 0x1EC00000000000, 1029);
  23 }
  24
  25 #elif defined(LIBC_TYPES_LONG_DOUBLE_IS_X86_FLOAT80)
  26
  27 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat80Simple) {
  28   eisel_lemire_test(123, 0, 0xf600000000000000, 16389);
  29   eisel_lemire_test(12345678901234568192u, 0, 0xab54a98ceb1f0c00, 16446);
  30 }
  31
  32 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat80LongerMantissa) {
  33 #if __SIZEOF_LONG_DOUBLE__ == 16
  34   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, 0,
  35                     0x91a2b3c091a2b3c1, 16507);
  36   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, 300,
  37                     0xd97757de56adb65c, 17503);
  38   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, -300,
  39                     0xc30feb9a7618457d, 15510);
  40 #elif __SIZEOF_LONG_DOUBLE__ == 12
  41   eisel_lemire_test(0x12345678'12345678'12345678_u96, 0, 0x91a2b3c091a2b3c1,
  42                     16475);
  43   eisel_lemire_test(0x12345678'12345678'12345678_u96, 300, 0xd97757de56adb65c,
  44                     17471);
  45   eisel_lemire_test(0x12345678'12345678'12345678_u96, -300, 0xc30feb9a7618457d,
  46                     15478);
  47 #else
  48 #error "unhandled long double type"
  49 #endif
  50 }
  51
  52 // These tests check numbers at the edge of the DETAILED_POWERS_OF_TEN table.
  53 // This doesn't reach very far into the range for long doubles, since it's sized
  54 // for doubles and their 11 exponent bits, and not for long doubles and their
  55 // 15 exponent bits. This is a known tradeoff, and was made because a proper
  56 // long double table would be approximately 16 times longer (specifically the
  57 // maximum exponent would need to be about 5000, leading to a 10,000 entry
  58 // table). This would have significant memory and storage costs all the time to
  59 // speed up a relatively uncommon path.
  60 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat80TableLimits) {
  61   eisel_lemire_test(1, 347, 0xd13eb46469447567, 17535);
  62   eisel_lemire_test(1, -348, 0xfa8fd5a0081c0288, 15226);
  63 }
  64
  65 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat80Fallback) {
  66   // This number is halfway between two possible results, and the algorithm
  67   // can't determine which is correct.
  68   ASSERT_FALSE(internal::eisel_lemire<long double>({12345678901234567890u, 1})
  69                    .has_value());
  70
  71   // These numbers' exponents are out of range for the current powers of ten
  72   // table.
  73   ASSERT_FALSE(internal::eisel_lemire<long double>({1, 1000}).has_value());
  74   ASSERT_FALSE(internal::eisel_lemire<long double>({1, -1000}).has_value());
  75 }
  76
  77 TEST_F(LlvmLibcStrToLongDblTest, ClingerFastPathFloat80Simple) {
  78   clinger_fast_path_test(123, 0, 0xf600000000000000, 16389);
  79   clinger_fast_path_test(1234567, 1, 0xbc61460000000000, 16406);
  80   clinger_fast_path_test(12345, -5, 0xfcd35a858793dd98, 16379);
  81 }
  82
  83 #elif defined(LIBC_TYPES_LONG_DOUBLE_IS_FLOAT128)
  84
  85 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat128Simple) {
  86   eisel_lemire_test(123, 0, 0x1ec00'00000000'00000000'00000000_u128, 16389);
  87   eisel_lemire_test(12345678901234568192u, 0,
  88                     0x156a9'5319d63e'18000000'00000000_u128, 16446);
  89 }
  90
  91 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat128LongerMantissa) {
  92   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, 0,
  93                     0x12345'67812345'67812345'67812345_u128, 16507);
  94   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, 300,
  95                     0x1b2ee'afbcad5b'6cb8b445'1dfcde19_u128, 17503);
  96   eisel_lemire_test(0x12345678'12345678'12345678'12345678_u128, -300,
  97                     0x1861f'd734ec30'8afa7189'f0f7595f_u128, 15510);
  98 }
  99
 100 TEST_F(LlvmLibcStrToLongDblTest, EiselLemireFloat128Fallback) {
 101   ASSERT_FALSE(internal::eisel_lemire<long double>(
 102                    {0x5ce0e9a5'6015fec5'aadfa328'ae39b333_u128, 1})
 103                    .has_value());
 104 }
 105
 106 TEST_F(LlvmLibcStrToLongDblTest, ClingerFastPathFloat128Simple) {
 107   clinger_fast_path_test(123, 0, 0x1ec00'00000000'00000000'00000000_u128,
 108                          16389);
 109   clinger_fast_path_test(1234567, 1, 0x178c2'8c000000'00000000'00000000_u128,
 110                          16406);
 111   clinger_fast_path_test(12345, -5, 0x1f9a6'b50b0f27'bb2fec56'd5cfaace_u128,
 112                          16379);
 113 }
 114
 115 #else
 116 #error "Unknown long double type"
 117 #endif
 118
 119 } // namespace LIBC_NAMESPACE_DECL