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go/test/fixedbugs/issue24937.go
Josh Bleecher Snyder 566e3e074c cmd/compile: avoid runtime call during switch string(byteslice)
This triggers three times while building std,
once in image/png and twice in go/internal/gccgoimporter.

There are no instances in std in which a more aggressive
optimization would have triggered.

This doesn't necessarily avoid an allocation,
because escape analysis is already able in many cases
to use a temporary backing for the string,
but it does at a minimum avoid the runtime call and copy.

Fixes #24937

Change-Id: I7019e85638ba8cd7e2f03890e672558b858579bc
Reviewed-on: https://go-review.googlesource.com/108035
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2018-04-21 00:50:50 +00:00

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305 B
Go

// run
// 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 main
func main() {
x := []byte{'a'}
switch string(x) {
case func() string { x[0] = 'b'; return "b" }():
panic("FAIL")
}
}