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go/test/fixedbugs/issue4085b.go
Martin Möhrmann e6f9f39ce5 cmd/compile: generate makeslice calls with int arguments
Where possible generate calls to runtime makeslice with int arguments
during compile time instead of makeslice with int64 arguments.

This eliminates converting arguments for calls to makeslice with
int64 arguments for platforms where int64 values do not fit into
arguments of type int.

godoc 386 binary shrinks by approximately 12 kilobyte.

amd64:
name         old time/op  new time/op  delta
MakeSlice-2  29.8ns ± 1%  29.8ns ± 1%   ~     (p=1.000 n=24+24)

386:
name         old time/op  new time/op  delta
MakeSlice-2  52.3ns ± 0%  45.9ns ± 0%  -12.17%  (p=0.000 n=25+22)

Fixes  #15357

Change-Id: Icb8701bb63c5a83877d26c8a4b78e782ba76de7c
Reviewed-on: https://go-review.googlesource.com/27851
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-08-29 18:25:33 +00:00

54 lines
1.3 KiB
Go

// run
// Copyright 2013 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 main
import (
"strings"
"unsafe"
)
type T []int
func main() {
n := -1
shouldPanic("len out of range", func() { _ = make(T, n) })
shouldPanic("cap out of range", func() { _ = make(T, 0, n) })
shouldPanic("len out of range", func() { _ = make(T, int64(n)) })
shouldPanic("cap out of range", func() { _ = make(T, 0, int64(n)) })
var t *byte
if unsafe.Sizeof(t) == 8 {
n = 1 << 20
n <<= 20
shouldPanic("len out of range", func() { _ = make(T, n) })
shouldPanic("cap out of range", func() { _ = make(T, 0, n) })
n <<= 20
shouldPanic("len out of range", func() { _ = make(T, n) })
shouldPanic("cap out of range", func() { _ = make(T, 0, n) })
} else {
n = 1<<31 - 1
shouldPanic("len out of range", func() { _ = make(T, n) })
shouldPanic("cap out of range", func() { _ = make(T, 0, n) })
shouldPanic("len out of range", func() { _ = make(T, int64(n)) })
shouldPanic("cap out of range", func() { _ = make(T, 0, int64(n)) })
}
}
func shouldPanic(str string, f func()) {
defer func() {
err := recover()
if err == nil {
panic("did not panic")
}
s := err.(error).Error()
if !strings.Contains(s, str) {
panic("got panic " + s + ", want " + str)
}
}()
f()
}