diff --git a/src/cmd/compile/fmt_test.go b/src/cmd/compile/fmt_test.go
deleted file mode 100644
index 6398a84f8f..0000000000
--- a/src/cmd/compile/fmt_test.go
+++ /dev/null
@@ -1,615 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file implements TestFormats; a test that verifies
-// format strings in the compiler (this directory and all
-// subdirectories, recursively).
-//
-// TestFormats finds potential (Printf, etc.) format strings.
-// If they are used in a call, the format verbs are verified
-// based on the matching argument type against a precomputed
-// map of valid formats (knownFormats). This map can be used to
-// automatically rewrite format strings across all compiler
-// files with the -r flag.
-//
-// The format map needs to be updated whenever a new (type,
-// format) combination is found and the format verb is not
-// 'v' or 'T' (as in "%v" or "%T"). To update the map auto-
-// matically from the compiler source's use of format strings,
-// use the -u flag. (Whether formats are valid for the values
-// to be formatted must be verified manually, of course.)
-//
-// The -v flag prints out the names of all functions called
-// with a format string, the names of files that were not
-// processed, and any format rewrites made (with -r).
-//
-// Run as: go test -run Formats [-r][-u][-v]
-//
-// Known shortcomings:
-// - indexed format strings ("%[2]s", etc.) are not supported
-//   (the test will fail)
-// - format strings that are not simple string literals cannot
-//   be updated automatically
-//   (the test will fail with respective warnings)
-// - format strings in _test packages outside the current
-//   package are not processed
-//   (the test will report those files)
-//
-package main_test
-
-import (
-	"bytes"
-	"flag"
-	"fmt"
-	"go/ast"
-	"go/build"
-	"go/constant"
-	"go/format"
-	"go/importer"
-	"go/parser"
-	"go/token"
-	"go/types"
-	"internal/testenv"
-	"io"
-	"io/fs"
-	"io/ioutil"
-	"log"
-	"os"
-	"path/filepath"
-	"sort"
-	"strconv"
-	"strings"
-	"testing"
-	"unicode/utf8"
-)
-
-var (
-	rewrite = flag.Bool("r", false, "rewrite format strings")
-	update  = flag.Bool("u", false, "update known formats")
-)
-
-// The following variables collect information across all processed files.
-var (
-	fset          = token.NewFileSet()
-	formatStrings = make(map[*ast.BasicLit]bool)      // set of all potential format strings found
-	foundFormats  = make(map[string]bool)             // set of all formats found
-	callSites     = make(map[*ast.CallExpr]*callSite) // map of all calls
-)
-
-// A File is a corresponding (filename, ast) pair.
-type File struct {
-	name string
-	ast  *ast.File
-}
-
-func TestFormats(t *testing.T) {
-	if testing.Short() && testenv.Builder() == "" {
-		t.Skip("Skipping in short mode")
-	}
-	testenv.MustHaveGoBuild(t) // more restrictive than necessary, but that's ok
-
-	// process all directories
-	filepath.WalkDir(".", func(path string, info fs.DirEntry, err error) error {
-		if info.IsDir() {
-			if info.Name() == "testdata" {
-				return filepath.SkipDir
-			}
-
-			importPath := filepath.Join("cmd/compile", path)
-			if ignoredPackages[filepath.ToSlash(importPath)] {
-				return filepath.SkipDir
-			}
-
-			pkg, err := build.Import(importPath, path, 0)
-			if err != nil {
-				if _, ok := err.(*build.NoGoError); ok {
-					return nil // nothing to do here
-				}
-				t.Fatal(err)
-			}
-			collectPkgFormats(t, pkg)
-		}
-		return nil
-	})
-
-	// test and rewrite formats
-	updatedFiles := make(map[string]File) // files that were rewritten
-	for _, p := range callSites {
-		// test current format literal and determine updated one
-		out := formatReplace(p.str, func(index int, in string) string {
-			if in == "*" {
-				return in // cannot rewrite '*' (as in "%*d")
-			}
-			// in != '*'
-			typ := p.types[index]
-			format := typ + " " + in // e.g., "*Node %n"
-
-			// Do not bother reporting basic types, nor %v, %T, %p.
-			// Vet handles basic types, and those three formats apply to all types.
-			if !strings.Contains(typ, ".") || (in == "%v" || in == "%T" || in == "%p") {
-				return in
-			}
-
-			// check if format is known
-			out, known := knownFormats[format]
-
-			// record format if not yet found
-			_, found := foundFormats[format]
-			if !found {
-				foundFormats[format] = true
-			}
-
-			// report an error if the format is unknown and this is the first
-			// time we see it; ignore "%v" and "%T" which are always valid
-			if !known && !found && in != "%v" && in != "%T" {
-				t.Errorf("%s: unknown format %q for %s argument", posString(p.arg), in, typ)
-			}
-
-			if out == "" {
-				out = in
-			}
-			return out
-		})
-
-		// replace existing format literal if it changed
-		if out != p.str {
-			// we cannot replace the argument if it's not a string literal for now
-			// (e.g., it may be "foo" + "bar")
-			lit, ok := p.arg.(*ast.BasicLit)
-			if !ok {
-				delete(callSites, p.call) // treat as if we hadn't found this site
-				continue
-			}
-
-			if testing.Verbose() {
-				fmt.Printf("%s:\n\t- %q\n\t+ %q\n", posString(p.arg), p.str, out)
-			}
-
-			// find argument index of format argument
-			index := -1
-			for i, arg := range p.call.Args {
-				if p.arg == arg {
-					index = i
-					break
-				}
-			}
-			if index < 0 {
-				// we may have processed the same call site twice,
-				// but that shouldn't happen
-				panic("internal error: matching argument not found")
-			}
-
-			// replace literal
-			new := *lit                    // make a copy
-			new.Value = strconv.Quote(out) // this may introduce "-quotes where there were `-quotes
-			p.call.Args[index] = &new
-			updatedFiles[p.file.name] = p.file
-		}
-	}
-
-	// write dirty files back
-	var filesUpdated bool
-	if len(updatedFiles) > 0 && *rewrite {
-		for _, file := range updatedFiles {
-			var buf bytes.Buffer
-			if err := format.Node(&buf, fset, file.ast); err != nil {
-				t.Errorf("WARNING: gofmt %s failed: %v", file.name, err)
-				continue
-			}
-			if err := ioutil.WriteFile(file.name, buf.Bytes(), 0x666); err != nil {
-				t.Errorf("WARNING: writing %s failed: %v", file.name, err)
-				continue
-			}
-			fmt.Printf("updated %s\n", file.name)
-			filesUpdated = true
-		}
-	}
-
-	// report the names of all functions called with a format string
-	if len(callSites) > 0 && testing.Verbose() {
-		set := make(map[string]bool)
-		for _, p := range callSites {
-			set[nodeString(p.call.Fun)] = true
-		}
-		var list []string
-		for s := range set {
-			list = append(list, s)
-		}
-		fmt.Println("\nFunctions called with a format string")
-		writeList(os.Stdout, list)
-	}
-
-	// update formats
-	if len(foundFormats) > 0 && *update {
-		var list []string
-		for s := range foundFormats {
-			list = append(list, fmt.Sprintf("%q: \"\",", s))
-		}
-		var buf bytes.Buffer
-		buf.WriteString(knownFormatsHeader)
-		writeList(&buf, list)
-		buf.WriteString("}\n")
-		out, err := format.Source(buf.Bytes())
-		const outfile = "fmtmap_test.go"
-		if err != nil {
-			t.Errorf("WARNING: gofmt %s failed: %v", outfile, err)
-			out = buf.Bytes() // continue with unformatted source
-		}
-		if err = ioutil.WriteFile(outfile, out, 0644); err != nil {
-			t.Errorf("WARNING: updating format map failed: %v", err)
-		}
-	}
-
-	// check that knownFormats is up to date
-	if !*rewrite && !*update {
-		var mismatch bool
-		for s := range foundFormats {
-			if _, ok := knownFormats[s]; !ok {
-				mismatch = true
-				break
-			}
-		}
-		if !mismatch {
-			for s := range knownFormats {
-				if _, ok := foundFormats[s]; !ok {
-					mismatch = true
-					break
-				}
-			}
-		}
-		if mismatch {
-			t.Errorf("format map is out of date; run 'go test -u' to update and manually verify correctness of change'")
-		}
-	}
-
-	// all format strings of calls must be in the formatStrings set (self-verification)
-	for _, p := range callSites {
-		if lit, ok := p.arg.(*ast.BasicLit); ok && lit.Kind == token.STRING {
-			if formatStrings[lit] {
-				// ok
-				delete(formatStrings, lit)
-			} else {
-				// this should never happen
-				panic(fmt.Sprintf("internal error: format string not found (%s)", posString(lit)))
-			}
-		}
-	}
-
-	// if we have any strings left, we may need to update them manually
-	if len(formatStrings) > 0 && filesUpdated {
-		var list []string
-		for lit := range formatStrings {
-			list = append(list, fmt.Sprintf("%s: %s", posString(lit), nodeString(lit)))
-		}
-		fmt.Println("\nWARNING: Potentially missed format strings")
-		writeList(os.Stdout, list)
-		t.Fail()
-	}
-
-	fmt.Println()
-}
-
-// A callSite describes a function call that appears to contain
-// a format string.
-type callSite struct {
-	file  File
-	call  *ast.CallExpr // call containing the format string
-	arg   ast.Expr      // format argument (string literal or constant)
-	str   string        // unquoted format string
-	types []string      // argument types
-}
-
-func collectPkgFormats(t *testing.T, pkg *build.Package) {
-	// collect all files
-	var filenames []string
-	filenames = append(filenames, pkg.GoFiles...)
-	filenames = append(filenames, pkg.CgoFiles...)
-	filenames = append(filenames, pkg.TestGoFiles...)
-
-	// TODO(gri) verify _test files outside package
-	for _, name := range pkg.XTestGoFiles {
-		// don't process this test itself
-		if name != "fmt_test.go" && testing.Verbose() {
-			fmt.Printf("WARNING: %s not processed\n", filepath.Join(pkg.Dir, name))
-		}
-	}
-
-	// make filenames relative to .
-	for i, name := range filenames {
-		filenames[i] = filepath.Join(pkg.Dir, name)
-	}
-
-	// parse all files
-	files := make([]*ast.File, len(filenames))
-	for i, filename := range filenames {
-		f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments)
-		if err != nil {
-			t.Fatal(err)
-		}
-		files[i] = f
-	}
-
-	// typecheck package
-	conf := types.Config{Importer: importer.Default()}
-	etypes := make(map[ast.Expr]types.TypeAndValue)
-	if _, err := conf.Check(pkg.ImportPath, fset, files, &types.Info{Types: etypes}); err != nil {
-		t.Fatal(err)
-	}
-
-	// collect all potential format strings (for extra verification later)
-	for _, file := range files {
-		ast.Inspect(file, func(n ast.Node) bool {
-			if s, ok := stringLit(n); ok && isFormat(s) {
-				formatStrings[n.(*ast.BasicLit)] = true
-			}
-			return true
-		})
-	}
-
-	// collect all formats/arguments of calls with format strings
-	for index, file := range files {
-		ast.Inspect(file, func(n ast.Node) bool {
-			if call, ok := n.(*ast.CallExpr); ok {
-				if ignoredFunctions[nodeString(call.Fun)] {
-					return true
-				}
-				// look for an arguments that might be a format string
-				for i, arg := range call.Args {
-					if s, ok := stringVal(etypes[arg]); ok && isFormat(s) {
-						// make sure we have enough arguments
-						n := numFormatArgs(s)
-						if i+1+n > len(call.Args) {
-							t.Errorf("%s: not enough format args (ignore %s?)", posString(call), nodeString(call.Fun))
-							break // ignore this call
-						}
-						// assume last n arguments are to be formatted;
-						// determine their types
-						argTypes := make([]string, n)
-						for i, arg := range call.Args[len(call.Args)-n:] {
-							if tv, ok := etypes[arg]; ok {
-								argTypes[i] = typeString(tv.Type)
-							}
-						}
-						// collect call site
-						if callSites[call] != nil {
-							panic("internal error: file processed twice?")
-						}
-						callSites[call] = &callSite{
-							file:  File{filenames[index], file},
-							call:  call,
-							arg:   arg,
-							str:   s,
-							types: argTypes,
-						}
-						break // at most one format per argument list
-					}
-				}
-			}
-			return true
-		})
-	}
-}
-
-// writeList writes list in sorted order to w.
-func writeList(w io.Writer, list []string) {
-	sort.Strings(list)
-	for _, s := range list {
-		fmt.Fprintln(w, "\t", s)
-	}
-}
-
-// posString returns a string representation of n's position
-// in the form filename:line:col: .
-func posString(n ast.Node) string {
-	if n == nil {
-		return ""
-	}
-	return fset.Position(n.Pos()).String()
-}
-
-// nodeString returns a string representation of n.
-func nodeString(n ast.Node) string {
-	var buf bytes.Buffer
-	if err := format.Node(&buf, fset, n); err != nil {
-		log.Fatal(err) // should always succeed
-	}
-	return buf.String()
-}
-
-// typeString returns a string representation of n.
-func typeString(typ types.Type) string {
-	s := filepath.ToSlash(typ.String())
-
-	// Report all the concrete IR types as Node, to shorten fmtmap.
-	const ir = "cmd/compile/internal/ir."
-	if s == "*"+ir+"Name" || s == "*"+ir+"Func" || s == "*"+ir+"Decl" ||
-		s == ir+"Ntype" || s == ir+"Expr" || s == ir+"Stmt" ||
-		strings.HasPrefix(s, "*"+ir) && (strings.HasSuffix(s, "Expr") || strings.HasSuffix(s, "Stmt")) {
-		return "cmd/compile/internal/ir.Node"
-	}
-
-	return s
-}
-
-// stringLit returns the unquoted string value and true if
-// n represents a string literal; otherwise it returns ""
-// and false.
-func stringLit(n ast.Node) (string, bool) {
-	if lit, ok := n.(*ast.BasicLit); ok && lit.Kind == token.STRING {
-		s, err := strconv.Unquote(lit.Value)
-		if err != nil {
-			log.Fatal(err) // should not happen with correct ASTs
-		}
-		return s, true
-	}
-	return "", false
-}
-
-// stringVal returns the (unquoted) string value and true if
-// tv is a string constant; otherwise it returns "" and false.
-func stringVal(tv types.TypeAndValue) (string, bool) {
-	if tv.IsValue() && tv.Value != nil && tv.Value.Kind() == constant.String {
-		return constant.StringVal(tv.Value), true
-	}
-	return "", false
-}
-
-// formatIter iterates through the string s in increasing
-// index order and calls f for each format specifier '%..v'.
-// The arguments for f describe the specifier's index range.
-// If a format specifier contains a "*", f is called with
-// the index range for "*" alone, before being called for
-// the entire specifier. The result of f is the index of
-// the rune at which iteration continues.
-func formatIter(s string, f func(i, j int) int) {
-	i := 0     // index after current rune
-	var r rune // current rune
-
-	next := func() {
-		r1, w := utf8.DecodeRuneInString(s[i:])
-		if w == 0 {
-			r1 = -1 // signal end-of-string
-		}
-		r = r1
-		i += w
-	}
-
-	flags := func() {
-		for r == ' ' || r == '#' || r == '+' || r == '-' || r == '0' {
-			next()
-		}
-	}
-
-	index := func() {
-		if r == '[' {
-			log.Fatalf("cannot handle indexed arguments: %s", s)
-		}
-	}
-
-	digits := func() {
-		index()
-		if r == '*' {
-			i = f(i-1, i)
-			next()
-			return
-		}
-		for '0' <= r && r <= '9' {
-			next()
-		}
-	}
-
-	for next(); r >= 0; next() {
-		if r == '%' {
-			i0 := i
-			next()
-			flags()
-			digits()
-			if r == '.' {
-				next()
-				digits()
-			}
-			index()
-			// accept any letter (a-z, A-Z) as format verb;
-			// ignore anything else
-			if 'a' <= r && r <= 'z' || 'A' <= r && r <= 'Z' {
-				i = f(i0-1, i)
-			}
-		}
-	}
-}
-
-// isFormat reports whether s contains format specifiers.
-func isFormat(s string) (yes bool) {
-	formatIter(s, func(i, j int) int {
-		yes = true
-		return len(s) // stop iteration
-	})
-	return
-}
-
-// oneFormat reports whether s is exactly one format specifier.
-func oneFormat(s string) (yes bool) {
-	formatIter(s, func(i, j int) int {
-		yes = i == 0 && j == len(s)
-		return j
-	})
-	return
-}
-
-// numFormatArgs returns the number of format specifiers in s.
-func numFormatArgs(s string) int {
-	count := 0
-	formatIter(s, func(i, j int) int {
-		count++
-		return j
-	})
-	return count
-}
-
-// formatReplace replaces the i'th format specifier s in the incoming
-// string in with the result of f(i, s) and returns the new string.
-func formatReplace(in string, f func(i int, s string) string) string {
-	var buf []byte
-	i0 := 0
-	index := 0
-	formatIter(in, func(i, j int) int {
-		if sub := in[i:j]; sub != "*" { // ignore calls for "*" width/length specifiers
-			buf = append(buf, in[i0:i]...)
-			buf = append(buf, f(index, sub)...)
-			i0 = j
-		}
-		index++
-		return j
-	})
-	return string(append(buf, in[i0:]...))
-}
-
-// ignoredPackages is the set of packages which can
-// be ignored.
-var ignoredPackages = map[string]bool{}
-
-// ignoredFunctions is the set of functions which may have
-// format-like arguments but which don't do any formatting and
-// thus may be ignored.
-var ignoredFunctions = map[string]bool{}
-
-func init() {
-	// verify that knownFormats entries are correctly formatted
-	for key, val := range knownFormats {
-		// key must be "typename format", and format starts with a '%'
-		// (formats containing '*' alone are not collected in this map)
-		i := strings.Index(key, "%")
-		if i < 0 || !oneFormat(key[i:]) {
-			log.Fatalf("incorrect knownFormats key: %q", key)
-		}
-		// val must be "format" or ""
-		if val != "" && !oneFormat(val) {
-			log.Fatalf("incorrect knownFormats value: %q (key = %q)", val, key)
-		}
-	}
-}
-
-const knownFormatsHeader = `// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file implements the knownFormats map which records the valid
-// formats for a given type. The valid formats must correspond to
-// supported compiler formats implemented in fmt.go, or whatever
-// other format verbs are implemented for the given type. The map may
-// also be used to change the use of a format verb across all compiler
-// sources automatically (for instance, if the implementation of fmt.go
-// changes), by using the -r option together with the new formats in the
-// map. To generate this file automatically from the existing source,
-// run: go test -run Formats -u.
-//
-// See the package comment in fmt_test.go for additional information.
-
-package main_test
-
-// knownFormats entries are of the form "typename format" -> "newformat".
-// An absent entry means that the format is not recognized as valid.
-// An empty new format means that the format should remain unchanged.
-var knownFormats = map[string]string{
-`
diff --git a/src/cmd/compile/fmtmap_test.go b/src/cmd/compile/fmtmap_test.go
deleted file mode 100644
index a925ec05ac..0000000000
--- a/src/cmd/compile/fmtmap_test.go
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2018 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// This file implements the knownFormats map which records the valid
-// formats for a given type. The valid formats must correspond to
-// supported compiler formats implemented in fmt.go, or whatever
-// other format verbs are implemented for the given type. The map may
-// also be used to change the use of a format verb across all compiler
-// sources automatically (for instance, if the implementation of fmt.go
-// changes), by using the -r option together with the new formats in the
-// map. To generate this file automatically from the existing source,
-// run: go test -run Formats -u.
-//
-// See the package comment in fmt_test.go for additional information.
-
-package main_test
-
-// knownFormats entries are of the form "typename format" -> "newformat".
-// An absent entry means that the format is not recognized as valid.
-// An empty new format means that the format should remain unchanged.
-var knownFormats = map[string]string{
-	"*bytes.Buffer %s":                             "",
-	"*cmd/compile/internal/ssa.Block %s":           "",
-	"*cmd/compile/internal/ssa.Func %s":            "",
-	"*cmd/compile/internal/ssa.Register %s":        "",
-	"*cmd/compile/internal/ssa.Value %s":           "",
-	"*cmd/compile/internal/types.Sym %+v":          "",
-	"*cmd/compile/internal/types.Sym %S":           "",
-	"*cmd/compile/internal/types.Type %+v":         "",
-	"*cmd/compile/internal/types.Type %-S":         "",
-	"*cmd/compile/internal/types.Type %L":          "",
-	"*cmd/compile/internal/types.Type %S":          "",
-	"*cmd/compile/internal/types.Type %s":          "",
-	"*math/big.Float %f":                           "",
-	"*math/big.Int %s":                             "",
-	"[]cmd/compile/internal/syntax.token %s":       "",
-	"cmd/compile/internal/arm.shift %d":            "",
-	"cmd/compile/internal/gc.RegIndex %d":          "",
-	"cmd/compile/internal/ir.Class %d":             "",
-	"cmd/compile/internal/ir.Node %+v":             "",
-	"cmd/compile/internal/ir.Node %L":              "",
-	"cmd/compile/internal/ir.Nodes %+v":            "",
-	"cmd/compile/internal/ir.Nodes %.v":            "",
-	"cmd/compile/internal/ir.Op %+v":               "",
-	"cmd/compile/internal/ssa.Aux %#v":             "",
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-	"cmd/compile/internal/ssa.LocalSlot %s":        "",
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-	"reflect.Type %s":                              "",
-	"time.Duration %d":                             "",
-}