modernc.org/gc@v1.0.1-0.20240304020402-f0dba7c97c2b/testdata/errchk/test/mergemul.go (about)

     1  // runoutput
     2  
     3  // Copyright 2017 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  import "fmt"
    10  
    11  // Check that expressions like (c*n + d*(n+k)) get correctly merged by
    12  // the compiler into (c+d)*n + d*k (with c+d and d*k computed at
    13  // compile time).
    14  //
    15  // The merging is performed by a combination of the multiplication
    16  // merge rules
    17  //  (c*n + d*n) -> (c+d)*n
    18  // and the distributive multiplication rules
    19  //  c * (d+x)  ->  c*d + c*x
    20  
    21  // Generate a MergeTest that looks like this:
    22  //
    23  //   a8, b8 = m1*n8 + m2*(n8+k), (m1+m2)*n8 + m2*k
    24  //   if a8 != b8 {
    25  // 	   // print error msg and panic
    26  //   }
    27  func makeMergeAddTest(m1, m2, k int, size string) string {
    28  
    29  	model := "    a" + size + ", b" + size
    30  	model += fmt.Sprintf(" = %%d*n%s + %%d*(n%s+%%d), (%%d+%%d)*n%s + (%%d*%%d)", size, size, size)
    31  
    32  	test := fmt.Sprintf(model, m1, m2, k, m1, m2, m2, k)
    33  	test += fmt.Sprintf(`
    34      if a%s != b%s {
    35          fmt.Printf("MergeAddTest(%d, %d, %d, %s) failed\n")
    36          fmt.Printf("%%d != %%d\n", a%s, b%s)
    37          panic("FAIL")
    38      }
    39  `, size, size, m1, m2, k, size, size, size)
    40  	return test + "\n"
    41  }
    42  
    43  // Check that expressions like (c*n - d*(n+k)) get correctly merged by
    44  // the compiler into (c-d)*n - d*k (with c-d and d*k computed at
    45  // compile time).
    46  //
    47  // The merging is performed by a combination of the multiplication
    48  // merge rules
    49  //  (c*n - d*n) -> (c-d)*n
    50  // and the distributive multiplication rules
    51  //  c * (d-x)  ->  c*d - c*x
    52  
    53  // Generate a MergeTest that looks like this:
    54  //
    55  //   a8, b8 = m1*n8 - m2*(n8+k), (m1-m2)*n8 - m2*k
    56  //   if a8 != b8 {
    57  // 	   // print error msg and panic
    58  //   }
    59  func makeMergeSubTest(m1, m2, k int, size string) string {
    60  
    61  	model := "    a" + size + ", b" + size
    62  	model += fmt.Sprintf(" = %%d*n%s - %%d*(n%s+%%d), (%%d-%%d)*n%s - (%%d*%%d)", size, size, size)
    63  
    64  	test := fmt.Sprintf(model, m1, m2, k, m1, m2, m2, k)
    65  	test += fmt.Sprintf(`
    66      if a%s != b%s {
    67          fmt.Printf("MergeSubTest(%d, %d, %d, %s) failed\n")
    68          fmt.Printf("%%d != %%d\n", a%s, b%s)
    69          panic("FAIL")
    70      }
    71  `, size, size, m1, m2, k, size, size, size)
    72  	return test + "\n"
    73  }
    74  
    75  func makeAllSizes(m1, m2, k int) string {
    76  	var tests string
    77  	tests += makeMergeAddTest(m1, m2, k, "8")
    78  	tests += makeMergeAddTest(m1, m2, k, "16")
    79  	tests += makeMergeAddTest(m1, m2, k, "32")
    80  	tests += makeMergeAddTest(m1, m2, k, "64")
    81  	tests += makeMergeSubTest(m1, m2, k, "8")
    82  	tests += makeMergeSubTest(m1, m2, k, "16")
    83  	tests += makeMergeSubTest(m1, m2, k, "32")
    84  	tests += makeMergeSubTest(m1, m2, k, "64")
    85  	tests += "\n"
    86  	return tests
    87  }
    88  
    89  func main() {
    90  	fmt.Println(`package main
    91  
    92  import "fmt"
    93  
    94  var n8 int8 = 42
    95  var n16 int16 = 42
    96  var n32 int32 = 42
    97  var n64 int64 = 42
    98  
    99  func main() {
   100      var a8, b8 int8
   101      var a16, b16 int16
   102      var a32, b32 int32
   103      var a64, b64 int64
   104  `)
   105  
   106  	fmt.Println(makeAllSizes(03, 05, 0)) // 3*n + 5*n
   107  	fmt.Println(makeAllSizes(17, 33, 0))
   108  	fmt.Println(makeAllSizes(80, 45, 0))
   109  	fmt.Println(makeAllSizes(32, 64, 0))
   110  
   111  	fmt.Println(makeAllSizes(7, 11, +1)) // 7*n + 11*(n+1)
   112  	fmt.Println(makeAllSizes(9, 13, +2))
   113  	fmt.Println(makeAllSizes(11, 16, -1))
   114  	fmt.Println(makeAllSizes(17, 9, -2))
   115  
   116  	fmt.Println("}")
   117  }