compiler-rt/test/builtins/Unit/compiler_rt_logb_test.c

   1 // RUN: %clang_builtins %s %librt -o %t && %run %t
   2 //===-- compiler_rt_logb_test.c - Test __compiler_rt_logb -----------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file checks __compiler_rt_logb from the compiler_rt library for
  11 // conformance against libm.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #define DOUBLE_PRECISION
  16 #include <math.h>
  17 #include <stdio.h>
  18 #include "fp_lib.h"
  19
  20 int test__compiler_rt_logb(fp_t x) {
  21   fp_t crt_value = __compiler_rt_logb(x);
  22   fp_t libm_value = logb(x);
  23   // Compare actual rep, e.g. to avoid NaN != the same NaN
  24   if (toRep(crt_value) != toRep(libm_value)) {
  25     printf("error: in __compiler_rt_logb(%a [%lX]) = %a [%lX] !=  %a [%lX]\n",
  26            x, toRep(x), crt_value, toRep(crt_value), libm_value,
  27            toRep(libm_value));
  28     return 1;
  29   }
  30   return 0;
  31 }
  32
  33 double cases[] = {
  34     1.e-6, -1.e-6, NAN, -NAN, INFINITY, -INFINITY, -1,
  35     -0.0,  0.0,    1,   -2,   2,        -0.5,      0.5,
  36 };
  37
  38 #ifndef __GLIBC_PREREQ
  39 #define __GLIBC_PREREQ(x, y) 0
  40 #endif
  41
  42 int main() {
  43   // Do not the run the compiler-rt logb test case if using GLIBC version
  44   // < 2.23. Older versions might not compute to the same value as the
  45   // compiler-rt value.
  46 #if __GLIBC_PREREQ(2, 23)
  47   const unsigned N = sizeof(cases) / sizeof(cases[0]);
  48   unsigned i;
  49   for (i = 0; i < N; ++i) {
  50     if (test__compiler_rt_logb(cases[i])) return 1;
  51   }
  52
  53   // Test a moving 1 bit, especially to handle denormal values.
  54   // Test the negation as well.
  55   rep_t x = signBit;
  56   while (x) {
  57     if (test__compiler_rt_logb(fromRep(x))) return 1;
  58     if (test__compiler_rt_logb(fromRep(signBit ^ x))) return 1;
  59     x >>= 1;
  60   }
  61   // Also try a couple moving ones
  62   x = signBit | (signBit >> 1) | (signBit >> 2);
  63   while (x) {
  64     if (test__compiler_rt_logb(fromRep(x))) return 1;
  65     if (test__compiler_rt_logb(fromRep(signBit ^ x))) return 1;
  66     x >>= 1;
  67   }
  68 #else
  69   printf("skipped\n");
  70 #endif
  71
  72   return 0;
  73 }