defer tg.cleanup()
	tg.parallel()

	tmp, err := os.MkdirTemp("", "TestAbsolutePath")
	if err != nil {
		t.Fatal(err)
	}
	defer robustio.RemoveAll(tmp)

	file := filepath.Join(tmp, "a.go")
	err = os.WriteFile(file, []byte{}, 0644)
	if err != nil {
		t.Fatal(err)
	}
	dir := filepath.Join(tmp, "dir")
	err = os.Mkdir(dir, 0777)
	if err != nil {
		t.Fatal(err)
	}

	noVolume := file[len(filepath.VolumeName(file)):]

	path := filepath.Join("users", "xxx", "go")
	var src bytes.Buffer
	fmt.Fprintf(&src, "//line %s:1\n", filepath.Join(path, "foo.go"))

	if err := ioutil.WriteFile(f.Name(), src.Bytes(), 0660); err != nil {
		log.Fatal(err)
	}

	out, err := exec.Command("go", "tool", "compile", "-p=p", fmt.Sprintf("-trimpath=%s", path), f.Name()).CombinedOutput()
	if err == nil {

import (
    "path/filepath"
	"fmt"
	"os"
)

func main() {
	for i := 0; i < 10; i++ {
		b := byte(0)
		if i > 5 {
			b = byte(i)
		}
        tmpl := "go test fuzz v1\nint(%d)\n"
		if err := os.WriteFile(filepath.Join(os.Args[1], fmt.Sprint(i)), []byte(fmt.Sprintf(tmpl, b)), 0777); err != nil {
			panic(err)
		}
	}

		// takes a while.
		t.Skip("skip in short mode")
	}
	testenv.MustHaveGoRun(t)
	t.Parallel()

	tmpdir := t.TempDir()
	src := filepath.Join(tmpdir, "x.go")
	err := os.WriteFile(src, []byte(helloSrc), 0644)
	if err != nil {
		t.Fatalf("write file failed: %v", err)
	}

	cmd := testenv.Command(t, testenv.GoToolPath(t), "run", "-gcflags=all="+flag, src)
	out, err := cmd.CombinedOutput()

			if in != out {
				if err := os.WriteFile(out, got, 0666); err != nil {
					t.Error(err)
				}
				return
			}
			// in == out: don't accidentally destroy input
			t.Errorf("WARNING: -update did not rewrite input file %s", in)
		}

		t.Errorf("(gofmt %s) != %s (see %s.gofmt)\n%s", in, out, in,
			diff.Diff("expected", expected, "got", got))
		if err := os.WriteFile(in+".gofmt", got, 0666); err != nil {

	buf.WriteString("// #cgo LDFLAGS:")
	for i := range 10000 {
		fmt.Fprintf(&buf, " -Wl,-rpath,/nonexistentpath/%d", i)
	}
	buf.WriteString("\n")
	buf.WriteString(`import "C"`+"\n")
	if err := os.WriteFile("generated.go", buf.Bytes(), 0o644); err != nil {
		log.Fatal(err)
	}
}
-- gen.go --
package p

		gomodPath := filepath.Join(dir, "go.mod")
		gomodData := []byte("module example.com/m\ngo 1.18\n")
		if err := os.WriteFile(gomodPath, gomodData, 0666); err != nil {
			t.Fatal(err)
		}
		helloPath := filepath.Join(dir, "hello.go")
		helloData := []byte("package main\nfunc main() {}\n")
		if err := os.WriteFile(helloPath, helloData, 0666); err != nil {
			t.Fatal(err)
		}
		outPath := filepath.Join(dir, path.Base(t.Name()))

	}

	name := filepath.Base(dir)
	db := filepath.Join(dir, name+".fossil")

	cgiPath := db + ".cgi"
	cgiScript := fmt.Sprintf("#!%s\nrepository: %s\n", h.fossilPath, db)
	if err := os.WriteFile(cgiPath, []byte(cgiScript), 0755); err != nil {
		return nil, err
	}

	handler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		if _, err := os.Stat(db); err != nil {

func (t *T) Unused() { println("THIS SHOULD BE ELIMINATED") }
func (t *T) Used() {}

var sink *T

func main() {
	var t T
	sink = &t
	t.Used()
}
`
	td := t.TempDir()

	if err := os.WriteFile(filepath.Join(td, "x.go"), []byte(prog), 0644); err != nil {
		t.Fatal(err)
	}
	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", "x.exe", "x.go")
	cmd.Dir = td
	if out, err := cmd.CombinedOutput(); err != nil {

	}
	defer os.RemoveAll(dir)

	// generate a very large function
	buf := bytes.NewBuffer(make([]byte, 0, 7000000))
	gen(buf)

	tmpfile := filepath.Join(dir, "x.s")
	err = os.WriteFile(tmpfile, buf.Bytes(), 0644)
	if err != nil {
		t.Fatalf("can't write output: %v\n", err)
	}

	pattern := `0x0080\s00128\s\(.*\)\tMOVD\t\$3,\sR3`

	// assemble generated file