compile, runtime: make selectnbrecv return two values

The only different between selectnbrecv and selectnbrecv2 is the later
set the input pointer value by second return value from chanrecv.

So by making selectnbrecv return two values from chanrecv, we can get
rid of selectnbrecv2, the compiler can now call only selectnbrecv and
generate simpler code.

This is the gofrontend version of https://golang.org/cl/292890.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/339529

1 files changed, 3 insertions, 28 deletions

diff --git a/libgo/go/runtime/chan.go b/libgo/go/runtime/chan.go
index 7878a8fe012..e3d0ad5acbe 100644
--- a/libgo/go/runtime/chan.go
+++ b/libgo/go/runtime/chan.go
@@ -33,7 +33,6 @@ import (
 //go:linkname closechan
 //go:linkname selectnbsend
 //go:linkname selectnbrecv
-//go:linkname selectnbrecv2
 
 const (
         maxAlign  = 8
@@ -712,28 +711,6 @@ func selectnbsend(c *hchan, elem unsafe.Pointer) (selected bool) {
 // compiler implements
 //
 //      select {
-//      case v = <-c:
-//              ... foo
-//      default:
-//              ... bar
-//      }
-//
-// as
-//
-//      if selectnbrecv(&v, c) {
-//              ... foo
-//      } else {
-//              ... bar
-//      }
-//
-func selectnbrecv(elem unsafe.Pointer, c *hchan) (selected bool) {
-        selected, _ = chanrecv(c, elem, false)
-        return
-}
-
-// compiler implements
-//
-//      select {
 //      case v, ok = <-c:
 //              ... foo
 //      default:
@@ -742,16 +719,14 @@ func selectnbrecv(elem unsafe.Pointer, c *hchan) (selected bool) {
 //
 // as
 //
-//      if c != nil && selectnbrecv2(&v, &ok, c) {
+//      if selected, ok = selectnbrecv(&v, c); selected {
 //              ... foo
 //      } else {
 //              ... bar
 //      }
 //
-func selectnbrecv2(elem unsafe.Pointer, received *bool, c *hchan) (selected bool) {
-        // TODO(khr): just return 2 values from this function, now that it is in Go.
-        selected, *received = chanrecv(c, elem, false)
-        return
+func selectnbrecv(elem unsafe.Pointer, c *hchan) (selected, received bool) {
+        return chanrecv(c, elem, false)
 }
 
 //go:linkname reflect_chansend reflect.chansend