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[dev.ssa] cmd/compile: get rid of nil checks before float loads/stores

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Just like we do for integer loads/stores.

Update #14511

Change-Id: Ic6ca6b54301438a5701ea5fb0be755451cb24d45
Reviewed-on: https://go-review.googlesource.com/19923
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
This commit is contained in:
Keith Randall 2016-02-25 13:45:22 -08:00
parent d3f15ff6bc
commit 4a346e7489
3 changed files with 41 additions and 1 deletions
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9
src/cmd/compile/internal/gc/ssa.go
View File

@ -4588,7 +4588,9 @@ func (s *genState) genValue(v *ssa.Value) {
case ssa.OpAMD64MOVQload, ssa.OpAMD64MOVLload, ssa.OpAMD64MOVWload, ssa.OpAMD64MOVBload,
ssa.OpAMD64MOVQstore, ssa.OpAMD64MOVLstore, ssa.OpAMD64MOVWstore, ssa.OpAMD64MOVBstore,
ssa.OpAMD64MOVBQSXload, ssa.OpAMD64MOVBQZXload, ssa.OpAMD64MOVWQSXload,
ssa.OpAMD64MOVWQZXload, ssa.OpAMD64MOVLQSXload, ssa.OpAMD64MOVLQZXload:
ssa.OpAMD64MOVWQZXload, ssa.OpAMD64MOVLQSXload, ssa.OpAMD64MOVLQZXload,
ssa.OpAMD64MOVSSload, ssa.OpAMD64MOVSDload, ssa.OpAMD64MOVOload,
ssa.OpAMD64MOVSSstore, ssa.OpAMD64MOVSDstore, ssa.OpAMD64MOVOstore:
if w.Args[0] == v.Args[0] && w.Aux == nil && w.AuxInt >= 0 && w.AuxInt < minZeroPage {
if Debug_checknil != 0 && int(v.Line) > 1 {
Warnl(int(v.Line), "removed nil check")
@ -4605,6 +4607,11 @@ func (s *genState) genValue(v *ssa.Value) {
}
}
if w.Type.IsMemory() {
if w.Op == ssa.OpVarDef || w.Op == ssa.OpVarKill || w.Op == ssa.OpVarLive {
// these ops are OK
mem = w
continue
}
// We can't delay the nil check past the next store.
break
}

18
test/nilptr3.go
View File

@ -193,3 +193,21 @@ func f4(x *[10]int) {
x = y
_ = &x[9] // ERROR "removed repeated nil check"
}
func f5(p *float32, q *float64, r *float32, s *float64) float64 {
x := float64(*p) // ERROR "removed nil check"
y := *q // ERROR "removed nil check"
*r = 7 // ERROR "removed nil check"
*s = 9 // ERROR "removed nil check"
return x + y
}
type T [29]byte
func f6(p, q *T) {
x := *p // ERROR "generated nil check"
// On ARM, the nil check on this store gets removed. On other archs,
// it doesn't. Makes this hard to test. SSA will always remove it.
//*q = x
_ = x
}

15
test/nilptr3_ssa.go
View File

@ -192,3 +192,18 @@ func f4(x *[10]int) {
x = y
_ = &x[9] // ERROR "removed[a-z ]* nil check"
}
func f5(p *float32, q *float64, r *float32, s *float64) float64 {
x := float64(*p) // ERROR "removed nil check"
y := *q // ERROR "removed nil check"
*r = 7 // ERROR "removed nil check"
*s = 9 // ERROR "removed nil check"
return x + y
}
type T [29]byte
func f6(p, q *T) {
x := *p // ERROR "removed nil check"
*q = x // ERROR "removed nil check"
}