return "", false
	}
	archCaps = fileArch
	fileArch = strings.ToLower(fileArch)
	fileArch = strings.TrimSuffix(fileArch, "splitload")
	fileArch = strings.TrimSuffix(fileArch, "latelower")
	if fileArch == goArch {
		return "", false
	}
	if fileArch == strings.TrimSuffix(goArch, "le") {
		return "", false
	}
	return archCaps, true
}

		disabled: !buildcfg.Experiment.PreemptibleLoops}, // insert resched checks in loops.
	{name: "lower", fn: lower, required: true},
	{name: "addressing modes", fn: addressingModes, required: false},
	{name: "late lower", fn: lateLower, required: true},
	{name: "lowered deadcode for cse", fn: deadcode}, // deadcode immediately before CSE avoids CSE making dead values live again
	{name: "lowered cse", fn: cse},
	{name: "elim unread autos", fn: elimUnreadAutos},

	return match, cond, result
}

func genRules(arch arch)          { genRulesSuffix(arch, "") }
func genSplitLoadRules(arch arch) { genRulesSuffix(arch, "splitload") }
func genLateLowerRules(arch arch) { genRulesSuffix(arch, "latelower") }

func genRulesSuffix(arch arch, suff string) {
	// Open input file.
	text, err := os.Open(arch.name + suff + ".rules")
	if err != nil {
		if suff == "" {
			// All architectures must have a plain rules file.