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 contstants. Especially useful for amd64/386. 9 10 package main 11 12 import "fmt" 13 14 func 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 32 func 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
