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go/test/fixedbugs/issue8947.go

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cmd/gc: synthesize zeroed value for non-assignment context CL 157910047 introduced code to turn a node representing a zeroed composite literal into N, the nil Node* pointer (which represents any zero, not the Go literal nil). That's great for assignments like x = T{}, but it doesn't work when T{} is used in a value context like T{}.v or x == T{}. Fix those. Should have no effect on performance; confirmed. The deltas below are noise (compare ns/op): benchmark old ns/op new ns/op delta BenchmarkBinaryTree17 2902919192 2915228424 +0.42% BenchmarkFannkuch11 2597417605 2630363685 +1.27% BenchmarkFmtFprintfEmpty 73.7 74.8 +1.49% BenchmarkFmtFprintfString 196 199 +1.53% BenchmarkFmtFprintfInt 213 217 +1.88% BenchmarkFmtFprintfIntInt 336 356 +5.95% BenchmarkFmtFprintfPrefixedInt 289 294 +1.73% BenchmarkFmtFprintfFloat 415 416 +0.24% BenchmarkFmtManyArgs 1281 1271 -0.78% BenchmarkGobDecode 10271734 10307978 +0.35% BenchmarkGobEncode 8985021 9079442 +1.05% BenchmarkGzip 410233227 412266944 +0.50% BenchmarkGunzip 102114554 103272443 +1.13% BenchmarkHTTPClientServer 45297 44993 -0.67% BenchmarkJSONEncode 19499741 19498489 -0.01% BenchmarkJSONDecode 76436733 74247497 -2.86% BenchmarkMandelbrot200 4273814 4307292 +0.78% BenchmarkGoParse 4024594 4028937 +0.11% BenchmarkRegexpMatchEasy0_32 131 135 +3.05% BenchmarkRegexpMatchEasy0_1K 328 333 +1.52% BenchmarkRegexpMatchEasy1_32 115 117 +1.74% BenchmarkRegexpMatchEasy1_1K 931 948 +1.83% BenchmarkRegexpMatchMedium_32 216 217 +0.46% BenchmarkRegexpMatchMedium_1K 72669 72857 +0.26% BenchmarkRegexpMatchHard_32 3818 3809 -0.24% BenchmarkRegexpMatchHard_1K 121398 121945 +0.45% BenchmarkRevcomp 613996550 615145436 +0.19% BenchmarkTemplate 93678525 93267391 -0.44% BenchmarkTimeParse 414 411 -0.72% BenchmarkTimeFormat 396 399 +0.76% Fixes #8947. LGTM=r R=r, dave CC=golang-codereviews https://golang.org/cl/162130043
2014-10-24 08:27:39 -06:00
// run
// Copyright 2014 The Go Authors. All rights reserved.
cmd/gc: synthesize zeroed value for non-assignment context CL 157910047 introduced code to turn a node representing a zeroed composite literal into N, the nil Node* pointer (which represents any zero, not the Go literal nil). That's great for assignments like x = T{}, but it doesn't work when T{} is used in a value context like T{}.v or x == T{}. Fix those. Should have no effect on performance; confirmed. The deltas below are noise (compare ns/op): benchmark old ns/op new ns/op delta BenchmarkBinaryTree17 2902919192 2915228424 +0.42% BenchmarkFannkuch11 2597417605 2630363685 +1.27% BenchmarkFmtFprintfEmpty 73.7 74.8 +1.49% BenchmarkFmtFprintfString 196 199 +1.53% BenchmarkFmtFprintfInt 213 217 +1.88% BenchmarkFmtFprintfIntInt 336 356 +5.95% BenchmarkFmtFprintfPrefixedInt 289 294 +1.73% BenchmarkFmtFprintfFloat 415 416 +0.24% BenchmarkFmtManyArgs 1281 1271 -0.78% BenchmarkGobDecode 10271734 10307978 +0.35% BenchmarkGobEncode 8985021 9079442 +1.05% BenchmarkGzip 410233227 412266944 +0.50% BenchmarkGunzip 102114554 103272443 +1.13% BenchmarkHTTPClientServer 45297 44993 -0.67% BenchmarkJSONEncode 19499741 19498489 -0.01% BenchmarkJSONDecode 76436733 74247497 -2.86% BenchmarkMandelbrot200 4273814 4307292 +0.78% BenchmarkGoParse 4024594 4028937 +0.11% BenchmarkRegexpMatchEasy0_32 131 135 +3.05% BenchmarkRegexpMatchEasy0_1K 328 333 +1.52% BenchmarkRegexpMatchEasy1_32 115 117 +1.74% BenchmarkRegexpMatchEasy1_1K 931 948 +1.83% BenchmarkRegexpMatchMedium_32 216 217 +0.46% BenchmarkRegexpMatchMedium_1K 72669 72857 +0.26% BenchmarkRegexpMatchHard_32 3818 3809 -0.24% BenchmarkRegexpMatchHard_1K 121398 121945 +0.45% BenchmarkRevcomp 613996550 615145436 +0.19% BenchmarkTemplate 93678525 93267391 -0.44% BenchmarkTimeParse 414 411 -0.72% BenchmarkTimeFormat 396 399 +0.76% Fixes #8947. LGTM=r R=r, dave CC=golang-codereviews https://golang.org/cl/162130043
2014-10-24 08:27:39 -06:00
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Some uses of zeroed constants in non-assignment
// expressions broke with our more aggressive zeroing
// of assignments (internal compiler errors).
package main
func f1() {
type T [2]int
p := T{0, 1}
switch p {
case T{0, 0}:
panic("wrong1")
case T{0, 1}:
// ok
default:
panic("wrong2")
}
if p == (T{0, 0}) {
panic("wrong3")
} else if p == (T{0, 1}) {
// ok
} else {
panic("wrong4")
}
}
type T struct {
V int
}
var X = T{}.V
func f2() {
var x = T{}.V
if x != 0 {
panic("wrongx")
}
if X != 0 {
panic("wrongX")
}
}
func main() {
f1()
f2()
}