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https://github.com/golang/go
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ec4e8517cd
golang.org/cl/109517 optimized the compiler to avoid the allocation for make in append(x, make([]T, y)...). This was only implemented for the case that y has type int. This change extends the optimization to trigger for all integer types where the value is known at compile time to fit into an int. name old time/op new time/op delta ExtendInt-12 106ns ± 4% 106ns ± 0% ~ (p=0.351 n=10+6) ExtendUint64-12 1.03µs ± 5% 0.10µs ± 4% -90.01% (p=0.000 n=9+10) name old alloc/op new alloc/op delta ExtendInt-12 0.00B 0.00B ~ (all equal) ExtendUint64-12 13.6kB ± 0% 0.0kB -100.00% (p=0.000 n=10+10) name old allocs/op new allocs/op delta ExtendInt-12 0.00 0.00 ~ (all equal) ExtendUint64-12 1.00 ± 0% 0.00 -100.00% (p=0.000 n=10+10) Updates #29785 Change-Id: Ief7760097c285abd591712da98c5b02bc3961fcd Reviewed-on: https://go-review.googlesource.com/c/go/+/182559 Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
116 lines
2.9 KiB
Go
116 lines
2.9 KiB
Go
// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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// This file contains code generation tests related to the handling of
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// slice types.
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// ------------------ //
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// Clear //
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// ------------------ //
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// Issue #5373 optimize memset idiom
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func SliceClear(s []int) []int {
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// amd64:`.*memclrNoHeapPointers`
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for i := range s {
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s[i] = 0
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}
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return s
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}
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func SliceClearPointers(s []*int) []*int {
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// amd64:`.*memclrHasPointers`
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for i := range s {
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s[i] = nil
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}
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return s
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}
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// ------------------ //
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// Extension //
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// ------------------ //
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// Issue #21266 - avoid makeslice in append(x, make([]T, y)...)
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func SliceExtensionConst(s []int) []int {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:-`.*runtime\.panicmakeslicelen`
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return append(s, make([]int, 1<<2)...)
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}
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func SliceExtensionConstInt64(s []int) []int {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:-`.*runtime\.panicmakeslicelen`
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return append(s, make([]int, int64(1<<2))...)
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}
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func SliceExtensionConstUint64(s []int) []int {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:-`.*runtime\.panicmakeslicelen`
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return append(s, make([]int, uint64(1<<2))...)
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}
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func SliceExtensionConstUint(s []int) []int {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:-`.*runtime\.panicmakeslicelen`
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return append(s, make([]int, uint(1<<2))...)
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}
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func SliceExtensionPointer(s []*int, l int) []*int {
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// amd64:`.*runtime\.memclrHasPointers`
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// amd64:-`.*runtime\.makeslice`
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return append(s, make([]*int, l)...)
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}
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func SliceExtensionVar(s []byte, l int) []byte {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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return append(s, make([]byte, l)...)
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}
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func SliceExtensionVarInt64(s []byte, l int64) []byte {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:`.*runtime\.panicmakeslicelen`
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return append(s, make([]byte, l)...)
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}
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func SliceExtensionVarUint64(s []byte, l uint64) []byte {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:`.*runtime\.panicmakeslicelen`
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return append(s, make([]byte, l)...)
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}
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func SliceExtensionVarUint(s []byte, l uint) []byte {
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// amd64:`.*runtime\.memclrNoHeapPointers`
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// amd64:-`.*runtime\.makeslice`
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// amd64:`.*runtime\.panicmakeslicelen`
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return append(s, make([]byte, l)...)
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}
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func SliceExtensionInt64(s []int, l64 int64) []int {
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// 386:`.*runtime\.makeslice`
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// 386:-`.*runtime\.memclr`
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return append(s, make([]int, l64)...)
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}
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// ---------------------- //
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// Nil check of &s[0] //
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// ---------------------- //
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// See issue 30366
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func SliceNilCheck(s []int) {
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p := &s[0]
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// amd64:-`TESTB`
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_ = *p
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}
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