cmd/compile: remove nodeNeedsWrapper flag

CL 254397 attached OVARLIVE nodes to OCALLxxx nodes Nbody.

The NeedsWrapper flag is now redundant with n.Nbody.Len() > 0
condition, so use that condition instead and remove the flag.

Passes toolstash-check.

Change-Id: Iebc3e674d3c0040a876ca4be05025943d2b4fb31
Reviewed-on: https://go-review.googlesource.com/c/go/+/254398
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Author: cuonglm

src/cmd/compile/internal/gc/order.go

@@ -496,7 +496,6 @@ func (o *Order) call(n *Node) {
 			arg.Left = x
 			x.Name.SetAddrtaken(true) // ensure SSA keeps the x variable
 			n.Nbody.Append(typecheck(nod(OVARLIVE, x, nil), ctxStmt))
-			n.SetNeedsWrapper(true)
 		}
 	}
 

src/cmd/compile/internal/gc/syntax.go

@@ -141,20 +141,19 @@ const (
 	nodeInitorder, _                   // tracks state during init1; two bits
 	_, _                               // second nodeInitorder bit
 	_, nodeHasBreak
-	_, nodeNoInline     // used internally by inliner to indicate that a function call should not be inlined; set for OCALLFUNC and OCALLMETH only
-	_, nodeImplicit     // implicit OADDR or ODEREF; ++/-- statement represented as OASOP; or ANDNOT lowered to OAND
-	_, nodeIsDDD        // is the argument variadic
-	_, nodeDiag         // already printed error about this
-	_, nodeColas        // OAS resulting from :=
-	_, nodeNonNil       // guaranteed to be non-nil
-	_, nodeTransient    // storage can be reused immediately after this statement
-	_, nodeBounded      // bounds check unnecessary
-	_, nodeHasCall      // expression contains a function call
-	_, nodeLikely       // if statement condition likely
-	_, nodeHasVal       // node.E contains a Val
-	_, nodeHasOpt       // node.E contains an Opt
-	_, nodeEmbedded     // ODCLFIELD embedded type
-	_, nodeNeedsWrapper // OCALLxxx node that needs to be wrapped
+	_, nodeNoInline  // used internally by inliner to indicate that a function call should not be inlined; set for OCALLFUNC and OCALLMETH only
+	_, nodeImplicit  // implicit OADDR or ODEREF; ++/-- statement represented as OASOP; or ANDNOT lowered to OAND
+	_, nodeIsDDD     // is the argument variadic
+	_, nodeDiag      // already printed error about this
+	_, nodeColas     // OAS resulting from :=
+	_, nodeNonNil    // guaranteed to be non-nil
+	_, nodeTransient // storage can be reused immediately after this statement
+	_, nodeBounded   // bounds check unnecessary
+	_, nodeHasCall   // expression contains a function call
+	_, nodeLikely    // if statement condition likely
+	_, nodeHasVal    // node.E contains a Val
+	_, nodeHasOpt    // node.E contains an Opt
+	_, nodeEmbedded  // ODCLFIELD embedded type
 )
 
 func (n *Node) Class() Class     { return Class(n.flags.get3(nodeClass)) }
@@ -287,20 +286,6 @@ func (n *Node) SetIota(x int64) {
 	n.Xoffset = x
 }
 
-func (n *Node) NeedsWrapper() bool {
-	return n.flags&nodeNeedsWrapper != 0
-}
-
-// SetNeedsWrapper indicates that OCALLxxx node needs to be wrapped by a closure.
-func (n *Node) SetNeedsWrapper(b bool) {
-	switch n.Op {
-	case OCALLFUNC, OCALLMETH, OCALLINTER:
-	default:
-		Fatalf("Node.SetNeedsWrapper %v", n.Op)
-	}
-	n.flags.set(nodeNeedsWrapper, b)
-}
-
 // mayBeShared reports whether n may occur in multiple places in the AST.
 // Extra care must be taken when mutating such a node.
 func (n *Node) mayBeShared() bool {

src/cmd/compile/internal/gc/walk.go

@@ -231,12 +231,15 @@ func walkstmt(n *Node) *Node {
 		case OCOPY:
 			n.Left = copyany(n.Left, &n.Ninit, true)
 
-		default:
-			if n.Left.NeedsWrapper() {
+		case OCALLFUNC, OCALLMETH, OCALLINTER:
+			if n.Left.Nbody.Len() > 0 {
 				n.Left = wrapCall(n.Left, &n.Ninit)
 			} else {
 				n.Left = walkexpr(n.Left, &n.Ninit)
 			}
+
+		default:
+			n.Left = walkexpr(n.Left, &n.Ninit)
 		}
 
 	case OFOR, OFORUNTIL: