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dev.simd
go/test/codegen/slices.go
Alexander Musman bd80f74bc1 cmd/compile: fold shift through AND for slice operations 
Fold a shift through AND when the AND gets a zero-or-one operand (e.g.
from arithmetic shift by 63 of a 64-bit value) for a common case with
slice operations:

    ASR     $63, R2, R2
    AND     R3<<3, R2, R2
    ADD     R2, R0, R2

As the operands are 64-bit, we can transform it to:

    AND     R2->63, R3, R2
    ADD     R2<<3, R0, R2

Code size improvement:
compile: .text:     9088004 ->  9086292 (-0.02%)
etcd:    .text:    10500276 -> 10498964 (-0.01%)

Change-Id: Ibcd5e67173da39b77ceff77ca67812fb8be5a7b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/679895
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Mark Freeman <mark@golang.org>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
2025-07-24 13:47:20 -07:00

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// asmcheck
// 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.
package codegen
import "unsafe"
// This file contains code generation tests related to the handling of
// slice types.
// ------------------ //
// Clear //
// ------------------ //
// Issue #5373 optimize memset idiom
// Some of the clears get inlined, see #56997
func SliceClear(s []int) []int {
// amd64:`.*memclrNoHeapPointers`
// ppc64x:`.*memclrNoHeapPointers`
for i := range s {
s[i] = 0
}
return s
}
func SliceClearPointers(s []*int) []*int {
// amd64:`.*memclrHasPointers`
// ppc64x:`.*memclrHasPointers`
for i := range s {
s[i] = nil
}
return s
}
// ------------------ //
// Extension //
// ------------------ //
// Issue #21266 - avoid makeslice in append(x, make([]T, y)...)
func SliceExtensionConst(s []int) []int {
// amd64:-`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:-`.*runtime\.panicmakeslicelen`
// amd64:"MOVUPS\tX15"
// loong64:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.makeslice`
// ppc64x:-`.*runtime\.panicmakeslicelen`
return append(s, make([]int, 1<<2)...)
}
func SliceExtensionConstInt64(s []int) []int {
// amd64:-`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:-`.*runtime\.panicmakeslicelen`
// amd64:"MOVUPS\tX15"
// loong64:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.makeslice`
// ppc64x:-`.*runtime\.panicmakeslicelen`
return append(s, make([]int, int64(1<<2))...)
}
func SliceExtensionConstUint64(s []int) []int {
// amd64:-`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:-`.*runtime\.panicmakeslicelen`
// amd64:"MOVUPS\tX15"
// loong64:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.makeslice`
// ppc64x:-`.*runtime\.panicmakeslicelen`
return append(s, make([]int, uint64(1<<2))...)
}
func SliceExtensionConstUint(s []int) []int {
// amd64:-`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:-`.*runtime\.panicmakeslicelen`
// amd64:"MOVUPS\tX15"
// loong64:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.makeslice`
// ppc64x:-`.*runtime\.panicmakeslicelen`
return append(s, make([]int, uint(1<<2))...)
}
// On ppc64x and loong64 continue to use memclrNoHeapPointers
// for sizes >= 512.
func SliceExtensionConst512(s []int) []int {
// amd64:-`.*runtime\.memclrNoHeapPointers`
// loong64:`.*runtime\.memclrNoHeapPointers`
// ppc64x:`.*runtime\.memclrNoHeapPointers`
return append(s, make([]int, 1<<9)...)
}
func SliceExtensionPointer(s []*int, l int) []*int {
// amd64:`.*runtime\.memclrHasPointers`
// amd64:-`.*runtime\.makeslice`
// ppc64x:`.*runtime\.memclrHasPointers`
// ppc64x:-`.*runtime\.makeslice`
return append(s, make([]*int, l)...)
}
func SliceExtensionVar(s []byte, l int) []byte {
// amd64:`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// ppc64x:`.*runtime\.memclrNoHeapPointers`
// ppc64x:-`.*runtime\.makeslice`
return append(s, make([]byte, l)...)
}
func SliceExtensionVarInt64(s []byte, l int64) []byte {
// amd64:`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:`.*runtime\.panicmakeslicelen`
return append(s, make([]byte, l)...)
}
func SliceExtensionVarUint64(s []byte, l uint64) []byte {
// amd64:`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:`.*runtime\.panicmakeslicelen`
return append(s, make([]byte, l)...)
}
func SliceExtensionVarUint(s []byte, l uint) []byte {
// amd64:`.*runtime\.memclrNoHeapPointers`
// amd64:-`.*runtime\.makeslice`
// amd64:`.*runtime\.panicmakeslicelen`
return append(s, make([]byte, l)...)
}
func SliceExtensionInt64(s []int, l64 int64) []int {
// 386:`.*runtime\.makeslice`
// 386:-`.*runtime\.memclr`
return append(s, make([]int, l64)...)
}
// ------------------ //
// Make+Copy //
// ------------------ //
// Issue #26252 - avoid memclr for make+copy
func SliceMakeCopyLen(s []int) []int {
// amd64:`.*runtime\.mallocgc`
// amd64:`.*runtime\.memmove`
// amd64:-`.*runtime\.makeslice`
// ppc64x:`.*runtime\.mallocgc`
// ppc64x:`.*runtime\.memmove`
// ppc64x:-`.*runtime\.makeslice`
a := make([]int, len(s))
copy(a, s)
return a
}
func SliceMakeCopyLenPtr(s []*int) []*int {
// amd64:`.*runtime\.makeslicecopy`
// amd64:-`.*runtime\.makeslice\(`
// amd64:-`.*runtime\.typedslicecopy
// ppc64x:`.*runtime\.makeslicecopy`
// ppc64x:-`.*runtime\.makeslice\(`
// ppc64x:-`.*runtime\.typedslicecopy
a := make([]*int, len(s))
copy(a, s)
return a
}
func SliceMakeCopyConst(s []int) []int {
// amd64:`.*runtime\.makeslicecopy`
// amd64:-`.*runtime\.makeslice\(`
// amd64:-`.*runtime\.memmove`
a := make([]int, 4)
copy(a, s)
return a
}
func SliceMakeCopyConstPtr(s []*int) []*int {
// amd64:`.*runtime\.makeslicecopy`
// amd64:-`.*runtime\.makeslice\(`
// amd64:-`.*runtime\.typedslicecopy
a := make([]*int, 4)
copy(a, s)
return a
}
func SliceMakeCopyNoOptNoDeref(s []*int) []*int {
a := new([]*int)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
*a = make([]*int, 4)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(*a, s)
return *a
}
func SliceMakeCopyNoOptNoVar(s []*int) []*int {
a := make([][]*int, 1)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a[0] = make([]*int, 4)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(a[0], s)
return a[0]
}
func SliceMakeCopyNoOptBlank(s []*int) []*int {
var a []*int
// amd64:-`.*runtime\.makeslicecopy`
_ = make([]*int, 4)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(a, s)
return a
}
func SliceMakeCopyNoOptNoMake(s []*int) []*int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:-`.*runtime\.objectnew`
a := *new([]*int)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(a, s)
return a
}
func SliceMakeCopyNoOptNoHeapAlloc(s []*int) int {
// amd64:-`.*runtime\.makeslicecopy`
a := make([]*int, 4)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(a, s)
return cap(a)
}
func SliceMakeCopyNoOptNoCap(s []*int) []*int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 0, 4)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.typedslicecopy`
copy(a, s)
return a
}
func SliceMakeCopyNoOptNoCopy(s []*int) []*int {
copy := func(x, y []*int) {}
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 4)
// amd64:-`.*runtime\.makeslicecopy`
copy(a, s)
return a
}
func SliceMakeCopyNoOptWrongOrder(s []*int) []*int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 4)
// amd64:`.*runtime\.typedslicecopy`
// amd64:-`.*runtime\.makeslicecopy`
copy(s, a)
return a
}
func SliceMakeCopyNoOptWrongAssign(s []*int) []*int {
var a []*int
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
s = make([]*int, 4)
// amd64:`.*runtime\.typedslicecopy`
// amd64:-`.*runtime\.makeslicecopy`
copy(a, s)
return s
}
func SliceMakeCopyNoOptCopyLength(s []*int) (int, []*int) {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 4)
// amd64:`.*runtime\.typedslicecopy`
// amd64:-`.*runtime\.makeslicecopy`
n := copy(a, s)
return n, a
}
func SliceMakeCopyNoOptSelfCopy(s []*int) []*int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 4)
// amd64:`.*runtime\.typedslicecopy`
// amd64:-`.*runtime\.makeslicecopy`
copy(a, a)
return a
}
func SliceMakeCopyNoOptTargetReference(s []*int) []*int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]*int, 4)
// amd64:`.*runtime\.typedslicecopy`
// amd64:-`.*runtime\.makeslicecopy`
copy(a, s[:len(a)])
return a
}
func SliceMakeCopyNoOptCap(s []int) []int {
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.makeslice\(`
a := make([]int, len(s), 9)
// amd64:-`.*runtime\.makeslicecopy`
// amd64:`.*runtime\.memmove`
copy(a, s)
return a
}
func SliceMakeCopyNoMemmoveDifferentLen(s []int) []int {
// amd64:`.*runtime\.makeslicecopy`
// amd64:-`.*runtime\.memmove`
a := make([]int, len(s)-1)
// amd64:-`.*runtime\.memmove`
copy(a, s)
return a
}
func SliceMakeEmptyPointerToZerobase() []int {
// amd64:`LEAQ.+runtime\.zerobase`
// amd64:-`.*runtime\.makeslice`
return make([]int, 0)
}
// ---------------------- //
// Nil check of &s[0] //
// ---------------------- //
// See issue 30366
func SliceNilCheck(s []int) {
p := &s[0]
// amd64:-`TESTB`
_ = *p
}
// ---------------------- //
// Init slice literal //
// ---------------------- //
// See issue 21561
func InitSmallSliceLiteral() []int {
// amd64:`MOVQ\t[$]42`
return []int{42}
}
func InitNotSmallSliceLiteral() []int {
// amd64:`LEAQ\t.*stmp_`
return []int{
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
42,
}
}
// --------------------------------------- //
// Test PPC64 SUBFCconst folding rules //
// triggered by slice operations. //
// --------------------------------------- //
func SliceWithConstCompare(a []int, b int) []int {
var c []int = []int{1, 2, 3, 4, 5}
if b+len(a) < len(c) {
// ppc64x:-"NEG"
return c[b:]
}
return a
}
func SliceWithSubtractBound(a []int, b int) []int {
// ppc64x:"SUBC",-"NEG"
return a[(3 - b):]
}
// --------------------------------------- //
// ARM64 folding for slice masks //
// --------------------------------------- //
func SliceAndIndex(a []int, b int) int {
// arm64:"AND\tR[0-9]+->63","ADD\tR[0-9]+<<3"
return a[b:][b]
}
// --------------------------------------- //
// Code generation for unsafe.Slice //
// --------------------------------------- //
func Slice1(p *byte, i int) []byte {
// amd64:-"MULQ"
return unsafe.Slice(p, i)
}
func Slice0(p *struct{}, i int) []struct{} {
// amd64:-"MULQ"
return unsafe.Slice(p, i)
}
// --------------------------------------- //
// Code generation for slice bounds //
// checking comparison //
// --------------------------------------- //
func SlicePut(a []byte, c uint8) []byte {
// arm64:`CBZ\tR1`
a[0] = c
// arm64:`CMP\t\$1, R1`
a = a[1:]
a[0] = c
// arm64:`CMP\t\$2, R1`
a = a[1:]
a[0] = c
a = a[1:]
return a
}
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