diff options
| author | Michael Munday <mike.munday@ibm.com> | 2017-03-29 14:01:41 -0400 |
|---|---|---|
| committer | Michael Munday <mike.munday@ibm.com> | 2017-08-24 16:53:56 +0000 |
| commit | 744ebfde0460e1d8fff10672e4d1e8d9ece52556 (patch) | |
| tree | 30f9eca8178f7ce2b7534ab394e0e1dac4e42e60 /test/live.go | |
| parent | 18b48afec9be0a1da4b23bebace0dc9f081dcee1 (diff) | |
| download | go-git-744ebfde0460e1d8fff10672e4d1e8d9ece52556.tar.gz | |
cmd/compile: eliminate stores to unread auto variables
This is a crude compiler pass to eliminate stores to auto variables
that are only ever written to.
Eliminates an unnecessary store to x from the following code:
func f() int {
var x := 1
return *(&x)
}
Fixes #19765.
Change-Id: If2c63a8ae67b8c590b6e0cc98a9610939a3eeffa
Reviewed-on: https://go-review.googlesource.com/38746
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'test/live.go')
| -rw-r--r-- | test/live.go | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/test/live.go b/test/live.go index ef988a05e5..2eb442cd2f 100644 --- a/test/live.go +++ b/test/live.go @@ -239,15 +239,6 @@ func f14() { func g14() string -func f15() { - var x string - _ = &x - x = g15() // ERROR "live at call to g15: x$" - printstring(x) // ERROR "live at call to printstring: x$" -} - -func g15() string - // Checking that various temporaries do not persist or cause // ambiguously live values that must be zeroed. // The exact temporary names are inconsequential but we are @@ -384,10 +375,9 @@ func f25(b bool) { return } var x string - _ = &x - x = g15() // ERROR "live at call to g15: x$" - printstring(x) // ERROR "live at call to printstring: x$" -} // ERROR "live at call to deferreturn: x$" + x = g14() + printstring(x) +} func g25() @@ -641,6 +631,9 @@ type T40 struct { m map[int]int } +//go:noescape +func useT40(*T40) + func newT40() *T40 { ret := T40{} ret.m = make(map[int]int) // ERROR "live at call to makemap: &ret$" @@ -658,7 +651,7 @@ func good40() { ret.m = make(map[int]int) // ERROR "live at call to makemap: .autotmp_[0-9]+ ret$" t := &ret printnl() // ERROR "live at call to printnl: .autotmp_[0-9]+ ret$" - _ = t + useT40(t) // ERROR "live at call to useT40: .autotmp_[0-9]+ ret$" } func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$" |