Switch on AVX2

Author: jeschkies

go.mod

@@ -1,9 +1,9 @@
 module github.com/jeschkies/go-memmem
 
-go 1.22
+go 1.21
 
 
-toolchain go1.22.1
+toolchain go1.21.3
 
 require (
 	github.com/mmcloughlin/avo v0.5.0

pkg/search/asm.go

@@ -23,8 +23,8 @@ func main() {
 	Store(offset, ReturnIndex(0))
 	RET()
 
-	TEXT("indexAvx512", NOSPLIT, "func(haystack, needle []byte) int64")
-	Doc("indexAvx512 returns the first position the needle is in the haystack.")
+	TEXT("indexAvx2", NOSPLIT, "func(haystack, needle []byte) int64")
+	Doc("indexAvx2 returns the first position the needle is in the haystack.")
 
 	needlePtr := Load(Param("needle").Base(), GP64())
 	needleLenMain := Load(Param("needle").Len(), GP64()); DECQ(needleLenMain)

pkg/search/bytes_avx512_amd64.go

@@ -104,9 +104,9 @@ test_chunk_match:
 	MOVQ SI, ret+48(FP)
 	RET
 
-// func indexAvx512(haystack []byte, needle []byte) int64
+// func indexAvx2(haystack []byte, needle []byte) int64
 // Requires: AVX, AVX2, BMI
-TEXT ·indexAvx512(SB), NOSPLIT, $0-56
+TEXT ·indexAvx2(SB), NOSPLIT, $0-56
 	MOVQ needle_base+24(FP), AX
 	MOVQ needle_len+32(FP), CX
 	DECQ CX

pkg/search/bytes_avx512_amd64.s

@@ -7,8 +7,8 @@ import (
 )
 
 func init() {
-	if cpu.X86.HasAVX512 {
-		index = indexAvx512
+	if cpu.X86.HasAVX2 {
+		index = indexAvx2
 	} else {
 		index = func(haystack []byte, needle []byte) int64 { return int64(bytes.Index(haystack, needle)) }
 	}