mirror of
https://github.com/golang/go
synced 2024-11-07 15:06:16 -07:00
a8a60ac2a7
Changes the compiler to recognize the slice extension pattern append(x, make([]T, y)...) and replace it with growslice and an optional memclr to avoid an allocation for make([]T, y). Memclr is not called in case growslice already allocated a new cleared backing array when T contains pointers. amd64: name old time/op new time/op delta ExtendSlice/IntSlice 103ns ± 4% 57ns ± 4% -44.55% (p=0.000 n=18+18) ExtendSlice/PointerSlice 155ns ± 3% 77ns ± 3% -49.93% (p=0.000 n=20+20) ExtendSlice/NoGrow 50.2ns ± 3% 5.2ns ± 2% -89.67% (p=0.000 n=18+18) name old alloc/op new alloc/op delta ExtendSlice/IntSlice 64.0B ± 0% 32.0B ± 0% -50.00% (p=0.000 n=20+20) ExtendSlice/PointerSlice 64.0B ± 0% 32.0B ± 0% -50.00% (p=0.000 n=20+20) ExtendSlice/NoGrow 32.0B ± 0% 0.0B -100.00% (p=0.000 n=20+20) name old allocs/op new allocs/op delta ExtendSlice/IntSlice 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=20+20) ExtendSlice/PointerSlice 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=20+20) ExtendSlice/NoGrow 1.00 ± 0% 0.00 -100.00% (p=0.000 n=20+20) Fixes #21266 Change-Id: Idc3077665f63cbe89762b590c5967a864fd1c07f Reviewed-on: https://go-review.googlesource.com/109517 Run-TryBot: Martin Möhrmann <moehrmann@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
64 lines
1.4 KiB
Go
64 lines
1.4 KiB
Go
// 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
|
|
|
|
// This file contains code generation tests related to the handling of
|
|
// slice types.
|
|
|
|
// ------------------ //
|
|
// Clear //
|
|
// ------------------ //
|
|
|
|
// Issue #5373 optimize memset idiom
|
|
|
|
func SliceClear(s []int) []int {
|
|
// amd64:`.*memclrNoHeapPointers`
|
|
for i := range s {
|
|
s[i] = 0
|
|
}
|
|
return s
|
|
}
|
|
|
|
func SliceClearPointers(s []*int) []*int {
|
|
// amd64:`.*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`
|
|
return append(s, make([]int, 1<<2)...)
|
|
}
|
|
|
|
func SliceExtensionPointer(s []*int, l int) []*int {
|
|
// amd64:`.*runtime\.memclrHasPointers`
|
|
// amd64:-`.*runtime\.makeslice`
|
|
return append(s, make([]*int, l)...)
|
|
}
|
|
|
|
func SliceExtensionVar(s []byte, l int) []byte {
|
|
// amd64:`.*runtime\.memclrNoHeapPointers`
|
|
// amd64:-`.*runtime\.makeslice`
|
|
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)...)
|
|
}
|