libgo/go/runtime/float_test.go

   1 // Copyright 2021 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package runtime_test
   6
   7 import (
   8         "testing"
   9 )
  10
  11 func TestIssue48807(t *testing.T) {
  12         for _, i := range []uint64{
  13                 0x8234508000000001, // from issue48807
  14                 1<<56 + 1<<32 + 1,
  15         } {
  16                 got := float32(i)
  17                 dontwant := float32(float64(i))
  18                 if got == dontwant {
  19                         // The test cases above should be uint64s such that
  20                         // this equality doesn't hold. These examples trigger
  21                         // the case where using an intermediate float64 doesn't work.
  22                         t.Errorf("direct float32 conversion doesn't work: arg=%x got=%x dontwant=%x", i, got, dontwant)
  23                 }
  24         }
  25 }