source := filepath.Join("testdata", "fma.go")
	output := filepath.Join(tmpdir, "fma.exe")
	cmd := testenv.Command(t, gocmd, "build", "-o", output, source)
	// The hash-dependence on file path name is dodged by specifying "all hashes ending in 1" plus "all hashes ending in 0"
	// i.e., all hashes.  This will print all the FMAs; this test is only interested in one of them (that should appear near the end).

Go 1.23 introduces a new `GOARM64` environment variable, which specifies the minimum target version of the ARM64 architecture at compile time. Allowed values are `v8.{0-9}` and `v9.{0-5}`. This may be followed by an option specifying extensions implemented by target hardware. Valid options are `,lse` and `,crypto`.

The `GOARM64` environment variable defaults to `v8.0`.

### RISC-V {#riscv}

<!-- go.dev/issue/61476, CL 541135 -->

// position being filename:1:1.
func NewFileBase(filename string) *PosBase {
	return NewTrimmedFileBase(filename, false)
}

// NewTrimmedFileBase is like NewFileBase, but allows specifying Trimmed.
func NewTrimmedFileBase(filename string, trimmed bool) *PosBase {
	base := &PosBase{MakePos(nil, linebase, colbase), filename, linebase, colbase, trimmed}
	base.pos.base = base
	return base
}

//		Flags that cgo will pass to the compiler when compiling
//		C code.
//	CGO_CFLAGS_ALLOW
//		A regular expression specifying additional flags to allow
//		to appear in #cgo CFLAGS source code directives.
//		Does not apply to the CGO_CFLAGS environment variable.
//	CGO_CFLAGS_DISALLOW
//		A regular expression specifying flags that must be disallowed
//		from appearing in #cgo CFLAGS source code directives.

		Flags that cgo will pass to the compiler when compiling
		C code.
	CGO_CFLAGS_ALLOW
		A regular expression specifying additional flags to allow
		to appear in #cgo CFLAGS source code directives.
		Does not apply to the CGO_CFLAGS environment variable.
	CGO_CFLAGS_DISALLOW
		A regular expression specifying flags that must be disallowed
		from appearing in #cgo CFLAGS source code directives.

new inputs are found that provide the same coverage. These files are
distinct from those stored in testdata directory; clean does not remove
those files.

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.
	`,
}

var (
	cleanI         bool // clean -i flag
	cleanR         bool // clean -r flag
	cleanCache     bool // clean -cache flag
	cleanFuzzcache bool // clean -fuzzcache flag

		} else {
			tw.hdr.Typeflag = TypeReg
		}
	}

	// Round ModTime and ignore AccessTime and ChangeTime unless
	// the format is explicitly chosen.
	// This ensures nominal usage of WriteHeader (without specifying the format)
	// does not always result in the PAX format being chosen, which
	// causes a 1KiB increase to every header.
	if tw.hdr.Format == FormatUnknown {
		tw.hdr.ModTime = tw.hdr.ModTime.Round(time.Second)

// input 'example.com/foo@v0.1.0' could syntactically refer to the variant of
// the package loaded from either module! (See mod_get_ambiguous_pkg.txt.)
// If the argument is ambiguous, the user can often disambiguate by specifying
// explicit versions for *all* of the potential module paths involved.

import (
	"context"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"sort"
	"strconv"
	"strings"
	"sync"

The test binary also accepts flags that control execution of the test; these
flags are also accessible by 'go test'. See 'go help testflag' for details.

For more about build flags, see 'go help build'.
For more about specifying packages, see 'go help packages'.

See also: go build, go vet.
`,
}

var HelpTestflag = &base.Command{
	UsageLine: "testflag",
	Short:     "testing flags",
	Long: `

//
// The executable name is the last element of the import path.
// In module-aware mode, an additional rule is used on import paths
// consisting of two or more path elements. If the last element is
// a vN path element specifying the major version, then the
// second last element of the import path is used instead.
func (p *Package) exeFromImportPath() string {
	_, elem := pathpkg.Split(p.ImportPath)
	if cfg.ModulesEnabled {