github.com/tidwall/go@v0.0.0-20170415222209-6694a6888b7d/src/cmd/compile/internal/gc/float_test.go (about)

     1  // Copyright 2016 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 gc
     6  
     7  import "testing"
     8  
     9  // For GO386=387, make sure fucomi* opcodes are not used
    10  // for comparison operations.
    11  // Note that this test will fail only on a Pentium MMX
    12  // processor (with GOARCH=386 GO386=387), as it just runs
    13  // some code and looks for an unimplemented instruction fault.
    14  
    15  //go:noinline
    16  func compare1(a, b float64) bool {
    17  	return a < b
    18  }
    19  
    20  //go:noinline
    21  func compare2(a, b float32) bool {
    22  	return a < b
    23  }
    24  
    25  func TestFloatCompare(t *testing.T) {
    26  	if !compare1(3, 5) {
    27  		t.Errorf("compare1 returned false")
    28  	}
    29  	if !compare2(3, 5) {
    30  		t.Errorf("compare2 returned false")
    31  	}
    32  }
    33  
    34  // For GO386=387, make sure fucomi* opcodes are not used
    35  // for float->int conversions.
    36  
    37  //go:noinline
    38  func cvt1(a float64) uint64 {
    39  	return uint64(a)
    40  }
    41  
    42  //go:noinline
    43  func cvt2(a float64) uint32 {
    44  	return uint32(a)
    45  }
    46  
    47  //go:noinline
    48  func cvt3(a float32) uint64 {
    49  	return uint64(a)
    50  }
    51  
    52  //go:noinline
    53  func cvt4(a float32) uint32 {
    54  	return uint32(a)
    55  }
    56  
    57  //go:noinline
    58  func cvt5(a float64) int64 {
    59  	return int64(a)
    60  }
    61  
    62  //go:noinline
    63  func cvt6(a float64) int32 {
    64  	return int32(a)
    65  }
    66  
    67  //go:noinline
    68  func cvt7(a float32) int64 {
    69  	return int64(a)
    70  }
    71  
    72  //go:noinline
    73  func cvt8(a float32) int32 {
    74  	return int32(a)
    75  }
    76  
    77  // make sure to cover int, uint cases (issue #16738)
    78  //go:noinline
    79  func cvt9(a float64) int {
    80  	return int(a)
    81  }
    82  
    83  //go:noinline
    84  func cvt10(a float64) uint {
    85  	return uint(a)
    86  }
    87  
    88  //go:noinline
    89  func cvt11(a float32) int {
    90  	return int(a)
    91  }
    92  
    93  //go:noinline
    94  func cvt12(a float32) uint {
    95  	return uint(a)
    96  }
    97  
    98  func TestFloatConvert(t *testing.T) {
    99  	if got := cvt1(3.5); got != 3 {
   100  		t.Errorf("cvt1 got %d, wanted 3", got)
   101  	}
   102  	if got := cvt2(3.5); got != 3 {
   103  		t.Errorf("cvt2 got %d, wanted 3", got)
   104  	}
   105  	if got := cvt3(3.5); got != 3 {
   106  		t.Errorf("cvt3 got %d, wanted 3", got)
   107  	}
   108  	if got := cvt4(3.5); got != 3 {
   109  		t.Errorf("cvt4 got %d, wanted 3", got)
   110  	}
   111  	if got := cvt5(3.5); got != 3 {
   112  		t.Errorf("cvt5 got %d, wanted 3", got)
   113  	}
   114  	if got := cvt6(3.5); got != 3 {
   115  		t.Errorf("cvt6 got %d, wanted 3", got)
   116  	}
   117  	if got := cvt7(3.5); got != 3 {
   118  		t.Errorf("cvt7 got %d, wanted 3", got)
   119  	}
   120  	if got := cvt8(3.5); got != 3 {
   121  		t.Errorf("cvt8 got %d, wanted 3", got)
   122  	}
   123  	if got := cvt9(3.5); got != 3 {
   124  		t.Errorf("cvt9 got %d, wanted 3", got)
   125  	}
   126  	if got := cvt10(3.5); got != 3 {
   127  		t.Errorf("cvt10 got %d, wanted 3", got)
   128  	}
   129  	if got := cvt11(3.5); got != 3 {
   130  		t.Errorf("cvt11 got %d, wanted 3", got)
   131  	}
   132  	if got := cvt12(3.5); got != 3 {
   133  		t.Errorf("cvt12 got %d, wanted 3", got)
   134  	}
   135  }
   136  
   137  var sinkFloat float64
   138  
   139  func BenchmarkMul2(b *testing.B) {
   140  	for i := 0; i < b.N; i++ {
   141  		var m float64 = 1
   142  		for j := 0; j < 500; j++ {
   143  			m *= 2
   144  		}
   145  		sinkFloat = m
   146  	}
   147  }
   148  func BenchmarkMulNeg2(b *testing.B) {
   149  	for i := 0; i < b.N; i++ {
   150  		var m float64 = 1
   151  		for j := 0; j < 500; j++ {
   152  			m *= -2
   153  		}
   154  		sinkFloat = m
   155  	}
   156  }