1// runoutput
2
3// Copyright 2016 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// Generate test of strength reduction for multiplications
8// with constants. Especially useful for amd64/386.
9
10package main
11
12import "fmt"
13
14func testMul(fact, bits int) string {
15	n := fmt.Sprintf("testMul_%d_%d", fact, bits)
16	fmt.Printf("func %s(s int%d) {\n", n, bits)
17
18	want := 0
19	for i := 0; i < 200; i++ {
20		fmt.Printf(`	if want, got := int%d(%d), s*%d; want != got {
21		failed = true
22		fmt.Printf("got %d * %%d == %%d, wanted %d\n",  s, got)
23	}
24`, bits, want, i, i, want)
25		want += fact
26	}
27
28	fmt.Printf("}\n")
29	return fmt.Sprintf("%s(%d)", n, fact)
30}
31
32func main() {
33	fmt.Printf("package main\n")
34	fmt.Printf("import \"fmt\"\n")
35	fmt.Printf("var failed = false\n")
36
37	f1 := testMul(17, 32)
38	f2 := testMul(131, 64)
39
40	fmt.Printf("func main() {\n")
41	fmt.Println(f1)
42	fmt.Println(f2)
43	fmt.Printf("if failed {\n	panic(\"multiplication failed\")\n}\n")
44	fmt.Printf("}\n")
45}
46