cmd/compile: cleanup Order.cleanTempNoPop slightly

Passes toolstash-check.

Change-Id: Ia769e719e89e508201711775ea3e2cb3979387fa
Reviewed-on: https://go-review.googlesource.com/102215
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index 3a80c75bfc543252f7e7ff7a5a884e38749670ad..d3b5f738249d921bd9edcd6a7f64021abb97d364 100644 (file)
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -236,7 +236,8 @@ func (o *Order) popTemp(mark ordermarker) {
 // Cleantempnopop emits VARKILL and if needed VARLIVE instructions
 // to *out for each temporary above the mark on the temporary stack.
 // It does not pop the temporaries from the stack.
-func (o *Order) cleanTempNoPop(mark ordermarker, out *[]*Node) {
+func (o *Order) cleanTempNoPop(mark ordermarker) []*Node {
+       var out []*Node
        for i := len(o.temp) - 1; i >= int(mark); i-- {
                n := o.temp[i]
                if n.Name.Keepalive() {
@@ -244,18 +245,19 @@ func (o *Order) cleanTempNoPop(mark ordermarker, out *[]*Node) {
                        n.SetAddrtaken(true) // ensure SSA keeps the n variable
                        live := nod(OVARLIVE, n, nil)
                        live = typecheck(live, Etop)
-                       *out = append(*out, live)
+                       out = append(out, live)
                }
                kill := nod(OVARKILL, n, nil)
                kill = typecheck(kill, Etop)
-               *out = append(*out, kill)
+               out = append(out, kill)
        }
+       return out
 }
 
 // cleanTemp emits VARKILL instructions for each temporary above the
 // mark on the temporary stack and removes them from the stack.
 func (o *Order) cleanTemp(top ordermarker) {
-       o.cleanTempNoPop(top, &o.out)
+       o.out = append(o.out, o.cleanTempNoPop(top)...)
        o.popTemp(top)
 }
 
@@ -646,9 +648,7 @@ func (o *Order) stmt(n *Node) {
        case OFOR:
                t := o.markTemp()
                n.Left = o.exprInPlace(n.Left)
-               var l []*Node
-               o.cleanTempNoPop(t, &l)
-               n.Nbody.Prepend(l...)
+               n.Nbody.Prepend(o.cleanTempNoPop(t)...)
                orderBlock(&n.Nbody)
                n.Right = orderStmtInPlace(n.Right)
                o.out = append(o.out, n)
@@ -659,12 +659,8 @@ func (o *Order) stmt(n *Node) {
        case OIF:
                t := o.markTemp()
                n.Left = o.exprInPlace(n.Left)
-               var l []*Node
-               o.cleanTempNoPop(t, &l)
-               n.Nbody.Prepend(l...)
-               l = nil
-               o.cleanTempNoPop(t, &l)
-               n.Rlist.Prepend(l...)
+               n.Nbody.Prepend(o.cleanTempNoPop(t)...)
+               n.Rlist.Prepend(o.cleanTempNoPop(t)...)
                o.popTemp(t)
                orderBlock(&n.Nbody)
                orderBlock(&n.Rlist)
@@ -881,9 +877,11 @@ func (o *Order) stmt(n *Node) {
                // Also insert any ninit queued during the previous loop.
                // (The temporary cleaning must follow that ninit work.)
                for _, n3 := range n.List.Slice() {
-                       s := n3.Ninit.Slice()
-                       o.cleanTempNoPop(t, &s)
-                       n3.Nbody.Prepend(s...)
+                       n3.Nbody.Prepend(o.cleanTempNoPop(t)...)
+
+                       // TODO(mdempsky): Is this actually necessary?
+                       // walkselect appears to walk Ninit.
+                       n3.Nbody.Prepend(n3.Ninit.Slice()...)
                        n3.Ninit.Set(nil)
                }
 
@@ -1082,10 +1080,7 @@ func (o *Order) expr(n, lhs *Node) *Node {
                // Clean temporaries from first branch at beginning of second.
                // Leave them on the stack so that they can be killed in the outer
                // context in case the short circuit is taken.
-               var s []*Node
-
-               o.cleanTempNoPop(mark, &s)
-               n.Right = addinit(n.Right, s)
+               n.Right = addinit(n.Right, o.cleanTempNoPop(mark))
                n.Right = o.exprInPlace(n.Right)
 
        case OCALLFUNC,