// Use brute force when s and substr both are small
		if len(s) <= bytealg.MaxBruteForce {
			return bytealg.IndexString(s, substr)
		}
		c0 := substr[0]
		c1 := substr[1]
		i := 0
		t := len(s) - n + 1
		fails := 0
		for i < t {
			if s[i] != c0 {
				// IndexByte is faster than bytealg.IndexString, so use it as long as
				// we're not getting lots of false positives.
				o := IndexByte(s[i+1:t], c0)
				if o < 0 {

// Requires 2 <= len(b) <= MaxLen.
//
//go:noescape
func Index(a, b []byte) int

// IndexString returns the index of the first instance of b in a, or -1 if b is not present in a.
// Requires 2 <= len(b) <= MaxLen.
//
//go:noescape

// Requires 2 <= len(b) <= MaxLen.
func Index(a, b []byte) int {
	panic("unimplemented")
}

// IndexString returns the index of the first instance of b in a, or -1 if b is not present in a.
// Requires 2 <= len(b) <= MaxLen.
func IndexString(a, b string) int {
	panic("unimplemented")
}

// Cutover reports the number of failures of IndexByte we should tolerate

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package codegen

func IndexArray(x *[10]int, i int) int {
	// amd64:`CMOVQCC`
	return x[i]
}

func IndexString(x string, i int) byte {
	// amd64:`CMOVQ(LS|CC)`
	return x[i]
}

func IndexSlice(x []float64, i int) float64 {
	// amd64:`CMOVQ(LS|CC)`
	return x[i]
}

func SliceArray(x *[10]int, i, j int) []int {

#include "textflag.h"

TEXT ·Index(SB),NOSPLIT,$0-56
	MOVD	a_base+0(FP), R0
	MOVD	a_len+8(FP), R1
	MOVD	b_base+24(FP), R2
	MOVD	b_len+32(FP), R3
	MOVD	$ret+48(FP), R9
	B	indexbody<>(SB)

TEXT ·IndexString(SB),NOSPLIT,$0-40
	MOVD	a_base+0(FP), R0
	MOVD	a_len+8(FP), R1
	MOVD	b_base+16(FP), R2
	MOVD	b_len+24(FP), R3
	MOVD	$ret+32(FP), R9
	B	indexbody<>(SB)

// input:
//   R0: haystack

	LMG	b_base+24(FP), R3, R4 // R3=&sep[0], R4=len(sep)
	MOVD	$ret+48(FP), R5
	BR	indexbody<>(SB)

// Caller must confirm availability of vx facility before calling.
TEXT ·IndexString(SB),NOSPLIT|NOFRAME,$0-40
	LMG	a_base+0(FP), R1, R2  // R1=&s[0],   R2=len(s)
	LMG	b_base+16(FP), R3, R4 // R3=&sep[0], R4=len(sep)
	MOVD	$ret+32(FP), R5
	BR	indexbody<>(SB)

// s: string we are searching

#include "textflag.h"

TEXT ·Index(SB),NOSPLIT,$0-56
	MOVQ a_base+0(FP), DI
	MOVQ a_len+8(FP), DX
	MOVQ b_base+24(FP), R8
	MOVQ b_len+32(FP), AX
	MOVQ DI, R10
	LEAQ ret+48(FP), R11
	JMP  indexbody<>(SB)

TEXT ·IndexString(SB),NOSPLIT,$0-40
	MOVQ a_base+0(FP), DI
	MOVQ a_len+8(FP), DX
	MOVQ b_base+16(FP), R8
	MOVQ b_len+24(FP), AX
	MOVQ DI, R10
	LEAQ ret+32(FP), R11
	JMP  indexbody<>(SB)

			panicmem()
		}
		throw(note)
	case _SIGINTDIV:
		panicdivide()
	case _SIGFLOAT:
		panicfloat()
	default:
		panic(errorString(note))
	}
}

// indexNoFloat is bytealg.IndexString but safe to use in a note
// handler.
func indexNoFloat(s, t string) int {
	if len(t) == 0 {
		return 0
	}
	for i := 0; i < len(s); i++ {
		if s[i] == t[0] && stringslite.HasPrefix(s[i:], t) {

#ifdef GOARCH_ppc64le
	MOVBZ internal∕cpu·PPC64+const_offsetPPC64HasPOWER9(SB), R7
	CMP   R7, $1
	BNE   power8
	BR    indexbodyp9<>(SB)
#endif
power8:
	BR indexbody<>(SB)

TEXT ·IndexString<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-40
	// R3 = string
	// R4 = length
	// R5 = separator pointer
	// R6 = separator length

#ifdef GOARCH_ppc64le
	MOVBZ internal∕cpu·PPC64+const_offsetPPC64HasPOWER9(SB), R7

	} else {
		regexp.prefix, regexp.prefixComplete, regexp.prefixEnd = onePassPrefix(prog)
	}
	if regexp.prefix != "" {
		// TODO(rsc): Remove this allocation by adding
		// IndexString to package bytes.
		regexp.prefixBytes = []byte(regexp.prefix)
		regexp.prefixRune, _ = utf8.DecodeRuneInString(regexp.prefix)
	}

	n := len(prog.Inst)
	i := 0
	for matchSize[i] != 0 && matchSize[i] < n {