Revert "runtime: improve memmove for amd64"

This reverts commit 3607c5f4f18ad4d423e40996ebf7f46b2f79ce02.

This was causing failures on amd64 machines without AVX.

Fixes #16939

Change-Id: I70080fbb4e7ae791857334f2bffd847d08cb25fa
Reviewed-on: https://go-review.googlesource.com/28274
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 0 insertions, 104 deletions

diff --git a/src/runtime/memmove_test.go b/src/runtime/memmove_test.go
index 080ca28667..2124cb9d49 100755..100644
--- a/src/runtime/memmove_test.go
+++ b/src/runtime/memmove_test.go
@@ -5,9 +5,7 @@
 package runtime_test
 
 import (
-	"crypto/rand"
 	"fmt"
-	"internal/race"
 	. "runtime"
 	"testing"
 )
@@ -84,108 +82,6 @@ func TestMemmoveAlias(t *testing.T) {
 	}
 }
 
-func TestMemmoveLarge0x180000(t *testing.T) {
-	if race.Enabled {
-		t.Skip("skipping large memmove test under race detector")
-	}
-	testSize(t, 0x180000)
-}
-
-func TestMemmoveOverlapLarge0x120000(t *testing.T) {
-	if race.Enabled {
-		t.Skip("skipping large memmove test under race detector")
-	}
-	testOverlap(t, 0x120000)
-}
-
-func testSize(t *testing.T, size int) {
-	src := make([]byte, size)
-	dst := make([]byte, size)
-	_, _ = rand.Read(src)
-	_, _ = rand.Read(dst)
-
-	ref := make([]byte, size)
-	copyref(ref, dst)
-
-	for n := size - 50; n > 1; n >>= 1 {
-		for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
-			for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
-				copy(dst[y:y+n], src[x:x+n])
-				copyref(ref[y:y+n], src[x:x+n])
-				p := cmpb(dst, ref)
-				if p >= 0 {
-					t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, dst[p], ref[p])
-				}
-			}
-		}
-	}
-}
-
-func testOverlap(t *testing.T, size int) {
-	src := make([]byte, size)
-	test := make([]byte, size)
-	ref := make([]byte, size)
-	_, _ = rand.Read(src)
-
-	for n := size - 50; n > 1; n >>= 1 {
-		for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
-			for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
-				// Reset input
-				copyref(test, src)
-				copyref(ref, src)
-				copy(test[y:y+n], test[x:x+n])
-				if y <= x {
-					copyref(ref[y:y+n], ref[x:x+n])
-				} else {
-					copybw(ref[y:y+n], ref[x:x+n])
-				}
-				p := cmpb(test, ref)
-				if p >= 0 {
-					t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, test[p], ref[p])
-				}
-			}
-		}
-	}
-
-}
-
-// Forward copy.
-func copyref(dst, src []byte) {
-	for i, v := range src {
-		dst[i] = v
-	}
-}
-
-// Backwards copy
-func copybw(dst, src []byte) {
-	if len(src) == 0 {
-		return
-	}
-	for i := len(src) - 1; i >= 0; i-- {
-		dst[i] = src[i]
-	}
-}
-
-// Returns offset of difference
-func matchLen(a, b []byte, max int) int {
-	a = a[:max]
-	b = b[:max]
-	for i, av := range a {
-		if b[i] != av {
-			return i
-		}
-	}
-	return max
-}
-
-func cmpb(a, b []byte) int {
-	l := matchLen(a, b, len(a))
-	if l == len(a) {
-		return -1
-	}
-	return l
-}
-
 func benchmarkSizes(b *testing.B, sizes []int, fn func(b *testing.B, n int)) {
 	for _, n := range sizes {
 		b.Run(fmt.Sprint(n), func(b *testing.B) {