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cmd/compile: fix missing init nodes for len(string([]byte)) optimization

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CL 497276 added optimization for len(string([]byte)) by avoiding call to
slicebytetostring. However, the bytes to string expression may contain
init nodes, which need to be preserved. Otherwise, it would make the
liveness analysis confusing about the lifetime of temporary variables
created by init nodes.

Fixes #61778

Change-Id: I6d1280a7d61bcc75f11132af41bda086f084ab54
Reviewed-on: https://go-review.googlesource.com/c/go/+/516375
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Cuong Manh Le 2023-08-05 22:51:49 +07:00 committed by Gopher Robot
parent 4198193035
commit ea565f156b
2 changed files with 17 additions and 1 deletions
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5
src/cmd/compile/internal/walk/builtin.go
View File

@ -255,7 +255,10 @@ func walkLenCap(n *ir.UnaryExpr, init *ir.Nodes) ir.Node {
return mkcall("countrunes", n.Type(), init, typecheck.Conv(n.X.(*ir.ConvExpr).X, types.Types[types.TSTRING]))
}
if isByteCount(n) {
_, len := backingArrayPtrLen(cheapExpr(n.X.(*ir.ConvExpr).X, init))
conv := n.X.(*ir.ConvExpr)
walkStmtList(conv.Init())
init.Append(ir.TakeInit(conv)...)
_, len := backingArrayPtrLen(cheapExpr(conv.X, init))
return len
}

13
test/fixedbugs/issue61778.go Normal file
View File

@ -0,0 +1,13 @@
// compile
// Copyright 2023 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 p
func f(s []byte) {
switch "" {
case string(append(s, 'a')):
}
}