cmd/compile: generate makechan calls with int arguments
Where possible generate calls to runtime makechan with int arguments
during compile time instead of makechan with int64 arguments.
This eliminates converting arguments for calls to makechan with
int64 arguments for platforms where int64 values do not fit into
arguments of type int.
A similar optimization for makeslice was introduced in CL
golang.org/cl/27851.
386:
name old time/op new time/op delta
MakeChan/Byte 52.4ns ± 6% 45.0ns ± 1% -14.14% (p=0.000 n=10+10)
MakeChan/Int 54.5ns ± 1% 49.1ns ± 1% -9.87% (p=0.000 n=10+10)
MakeChan/Ptr 150ns ± 1% 143ns ± 0% -4.38% (p=0.000 n=9+7)
MakeChan/Struct/0 49.2ns ± 2% 43.2ns ± 2% -12.27% (p=0.000 n=10+10)
MakeChan/Struct/32 81.7ns ± 2% 76.2ns ± 1% -6.71% (p=0.000 n=10+10)
MakeChan/Struct/40 88.4ns ± 2% 82.5ns ± 2% -6.60% (p=0.000 n=10+10)
AMD64:
name old time/op new time/op delta
MakeChan/Byte 83.4ns ± 8% 80.8ns ± 3% ~ (p=0.171 n=10+10)
MakeChan/Int 101ns ± 3% 101ns ± 2% ~ (p=0.412 n=10+10)
MakeChan/Ptr 128ns ± 1% 128ns ± 1% ~ (p=0.191 n=10+10)
MakeChan/Struct/0 67.6ns ± 3% 68.7ns ± 4% ~ (p=0.224 n=10+10)
MakeChan/Struct/32 138ns ± 1% 139ns ± 1% ~ (p=0.185 n=10+9)
MakeChan/Struct/40 154ns ± 1% 154ns ± 1% -0.55% (p=0.027 n=10+9)
Change-Id: Ie854cb066007232c5e9f71ea7d6fe27e81a9c050
Reviewed-on: https://go-review.googlesource.com/55140
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/test/chancap.go b/test/chancap.go
index b3e4023..b08478a 100644
--- a/test/chancap.go
+++ b/test/chancap.go
@@ -8,8 +8,17 @@
package main
+import (
+ "strings"
+ "unsafe"
+)
+
+type T chan int
+
+const ptrSize = unsafe.Sizeof((*byte)(nil))
+
func main() {
- c := make(chan int, 10)
+ c := make(T, 10)
if len(c) != 0 || cap(c) != 10 {
println("chan len/cap ", len(c), cap(c), " want 0 10")
panic("fail")
@@ -23,9 +32,39 @@
panic("fail")
}
- c = make(chan int)
+ c = make(T)
if len(c) != 0 || cap(c) != 0 {
println("chan len/cap ", len(c), cap(c), " want 0 0")
panic("fail")
}
+
+ n := -1
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ shouldPanic("makechan: size out of range", func() { _ = make(T, int64(n)) })
+ if ptrSize == 8 {
+ n = 1 << 20
+ n <<= 20
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ n <<= 20
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ } else {
+ n = 1<<31 - 1
+ shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
+ shouldPanic("makechan: size out of range", func() { _ = make(T, 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()
}
