cmd/compile/internal/gc: cleanup walkselectcases slightly

Remove some unnecessary code. Most significantly, we can skip testing "if ch == nil { block() }", because this is already the semantics implied by normal send/receive operations. Updates #40410. Change-Id: I4acd33383cc876719fc3b998d85244d4ac1ff9d9 Reviewed-on: https://go-review.googlesource.com/c/go/+/245126 Run-TryBot: Matthew Dempsky <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Cuong Manh Le <[email protected]>
cloudflare · Aug 18, 2020 · a401718 · a401718
1 parent fe23ba4
commit a401718
Showing 1 changed file with 2 additions and 18 deletions.
diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go
@@ -123,17 +123,14 @@ func walkselectcases(cases *Nodes) []*Node {
  n := cas.Left
  l = append(l, n.Ninit.Slice()...)
  n.Ninit.Set(nil)
- var ch *Node
  switch n.Op {
  default:
  Fatalf("select %v", n.Op)
 
- // ok already
  case OSEND:
- ch = n.Left
+ // already ok
 
  case OSELRECV, OSELRECV2:
- ch = n.Right.Left
  if n.Op == OSELRECV || n.List.Len() == 0 {
  if n.Left == nil {
  n = n.Right
@@ -157,16 +154,7 @@ func walkselectcases(cases *Nodes) []*Node {
  n = typecheck(n, ctxStmt)
  }
 
- // if ch == nil { block() }; n;
- a := nod(OIF, nil, nil)
-
- a.Left = nod(OEQ, ch, nodnil())
- var ln Nodes
- ln.Set(l)
- a.Nbody.Set1(mkcall("block", nil, &ln))
- l = ln.Slice()
- a = typecheck(a, ctxStmt)
- l = append(l, a, n)
+ l = append(l, n)
  }
 
  l = append(l, cas.Nbody.Slice()...)
@@ -223,8 +211,6 @@ func walkselectcases(cases *Nodes) []*Node {
 
  case OSELRECV:
  // if selectnbrecv(&v, c) { body } else { default body }
- r = nod(OIF, nil, nil)
- r.Ninit.Set(cas.Ninit.Slice())
  ch := n.Right.Left
  elem := n.Left
  if elem == nil {
@@ -234,8 +220,6 @@ func walkselectcases(cases *Nodes) []*Node {
 
  case OSELRECV2:
  // if selectnbrecv2(&v, &received, c) { body } else { default body }
- r = nod(OIF, nil, nil)
- r.Ninit.Set(cas.Ninit.Slice())
  ch := n.Right.Left
  elem := n.Left
  if elem == nil {