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go/test/nilptr3.go

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// errorcheck -0 -d=nil
// Fails on power64x because of incomplete optimization. See issue 9058.
// +build !power64,!power64le
// 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.
// Test that nil checks are removed.
// Optimization is enabled.
package p
type Struct struct {
X int
Y float64
}
type BigStruct struct {
X int
Y float64
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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A [1 << 20]int
Z string
}
type Empty struct {
}
type Empty1 struct {
Empty
}
var (
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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intp *int
arrayp *[10]int
array0p *[0]int
bigarrayp *[1 << 26]int
structp *Struct
bigstructp *BigStruct
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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emptyp *Empty
empty1p *Empty1
)
func f1() {
_ = *intp // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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// This one should be removed but the block copy needs
// to be turned into its own pseudo-op in order to see
// the indirect.
_ = *arrayp // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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// 0-byte indirect doesn't suffice.
// we don't registerize globals, so there are no removed repeated nil checks.
_ = *array0p // ERROR "generated nil check"
_ = *array0p // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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_ = *intp // ERROR "generated nil check"
_ = *arrayp // ERROR "generated nil check"
_ = *structp // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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_ = *emptyp // ERROR "generated nil check"
_ = *arrayp // ERROR "generated nil check"
}
func f2() {
var (
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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intp *int
arrayp *[10]int
array0p *[0]int
bigarrayp *[1 << 20]int
structp *Struct
bigstructp *BigStruct
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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emptyp *Empty
empty1p *Empty1
)
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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_ = *intp // ERROR "generated nil check"
_ = *arrayp // ERROR "generated nil check"
_ = *array0p // ERROR "generated nil check"
_ = *array0p // ERROR "removed repeated nil check"
_ = *intp // ERROR "removed repeated nil check"
_ = *arrayp // ERROR "removed repeated nil check"
_ = *structp // ERROR "generated nil check"
_ = *emptyp // ERROR "generated nil check"
_ = *arrayp // ERROR "removed repeated nil check"
_ = *bigarrayp // ERROR "generated nil check" ARM removed nil check before indirect!!
_ = *bigstructp // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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_ = *empty1p // ERROR "generated nil check"
}
func fx10k() *[10000]int
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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var b bool
func f3(x *[10000]int) {
// Using a huge type and huge offsets so the compiler
// does not expect the memory hardware to fault.
_ = x[9999] // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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for {
if x[9999] != 0 { // ERROR "generated nil check"
break
}
}
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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x = fx10k()
_ = x[9999] // ERROR "generated nil check"
if b {
_ = x[9999] // ERROR "removed repeated nil check"
} else {
_ = x[9999] // ERROR "removed repeated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
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}
_ = x[9999] // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
x = fx10k()
if b {
_ = x[9999] // ERROR "generated nil check"
} else {
_ = x[9999] // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
}
_ = x[9999] // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
fx10k()
// This one is a bit redundant, if we figured out that
// x wasn't going to change across the function call.
// But it's a little complex to do and in practice doesn't
// matter enough.
_ = x[9999] // ERROR "generated nil check"
}
func f3a() {
x := fx10k()
y := fx10k()
z := fx10k()
_ = &x[9] // ERROR "generated nil check"
y = z
_ = &x[9] // ERROR "removed repeated nil check"
x = y
_ = &x[9] // ERROR "generated nil check"
}
func f3b() {
x := fx10k()
y := fx10k()
_ = &x[9] // ERROR "generated nil check"
y = x
_ = &x[9] // ERROR "removed repeated nil check"
x = y
_ = &x[9] // ERROR "removed repeated nil check"
}
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
func fx10() *[10]int
func f4(x *[10]int) {
// Most of these have no checks because a real memory reference follows,
// and the offset is small enough that if x is nil, the address will still be
// in the first unmapped page of memory.
_ = x[9] // ERROR "removed nil check before indirect"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
for {
if x[9] != 0 { // ERROR "removed nil check before indirect"
break
}
}
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
x = fx10()
_ = x[9] // ERROR "removed nil check before indirect"
if b {
_ = x[9] // ERROR "removed nil check before indirect"
} else {
_ = x[9] // ERROR "removed nil check before indirect"
}
_ = x[9] // ERROR "removed nil check before indirect"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
x = fx10()
if b {
_ = x[9] // ERROR "removed nil check before indirect"
} else {
_ = &x[9] // ERROR "generated nil check"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
}
_ = x[9] // ERROR "removed nil check before indirect"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
fx10()
_ = x[9] // ERROR "removed nil check before indirect"
cmd/gc: correct handling of globals, func args, results Globals, function arguments, and results are special cases in registerization. Globals must be flushed aggressively, because nearly any operation can cause a panic, and the recovery code must see the latest values. Globals also must be loaded aggressively, because nearly any store through a pointer might be updating a global: the compiler cannot see all the "address of" operations on globals, especially exported globals. To accomplish this, mark all globals as having their address taken, which effectively disables registerization. If a function contains a defer statement, the function results must be flushed aggressively, because nearly any operation can cause a panic, and the deferred code may call recover, causing the original function to return the current values of its function results. To accomplish this, mark all function results as having their address taken if the function contains any defer statements. This causes not just aggressive flushing but also aggressive loading. The aggressive loading is overkill but the best we can do in the current code. Function arguments must be considered live at all safe points in a function, because garbage collection always preserves them: they must be up-to-date in order to be preserved correctly. Accomplish this by marking them live at all call sites. An earlier attempt at this marked function arguments as having their address taken, which disabled registerization completely, making programs slower. This CL's solution allows registerization while preserving safety. The benchmark speedup is caused by being able to registerize again (the earlier CL lost the same amount). benchmark old ns/op new ns/op delta BenchmarkEqualPort32 61.4 56.0 -8.79% benchmark old MB/s new MB/s speedup BenchmarkEqualPort32 521.56 570.97 1.09x Fixes #1304. (again) Fixes #7944. (again) Fixes #7984. Fixes #7995. LGTM=khr R=golang-codereviews, khr CC=golang-codereviews, iant, r https://golang.org/cl/97500044
2014-05-15 13:34:53 -06:00
x = fx10()
y := fx10()
_ = &x[9] // ERROR "generated nil check"
y = x
_ = &x[9] // ERROR "removed repeated nil check"
x = y
_ = &x[9] // ERROR "removed repeated nil check"
}