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 <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go
index bae7ed3..3812a0e 100644
--- a/src/cmd/compile/internal/gc/select.go
+++ b/src/cmd/compile/internal/gc/select.go
@@ -123,17 +123,14 @@
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 @@
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 @@
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 @@
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 {
