cmd/compile: early return/continue to unindent some code

While at it, also simplify a couple of switches.

Doesn't pass toolstash -cmp on std cmd, because orderBlock(&n2.Nbody) is
moved further down to the n3 loop.

Change-Id: I20a2a6c21eb9a183a59572e0fca401a5041fc40a
Reviewed-on: https://go-review.googlesource.com/104416
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -332,13 +332,10 @@ func ismulticall(l Nodes) bool {
 	switch n.Op {
 	default:
 		return false
-
 	case OCALLFUNC, OCALLMETH, OCALLINTER:
-		break
-	}
-
 		// call must return multiple values
 		return n.Left.Type.NumResults() > 1
+	}
 }
 
 // copyRet emits t1, t2, ... = n, where n is a function call,
@@ -381,7 +378,9 @@ func (o *Order) call(n *Node) {
 	n.Right = o.expr(n.Right, nil) // ODDDARG temp
 	o.callArgs(&n.List)
 
-	if n.Op == OCALLFUNC {
+	if n.Op != OCALLFUNC {
+		return
+	}
 	keepAlive := func(i int) {
 		// If the argument is really a pointer being converted to uintptr,
 		// arrange for the pointer to be kept alive until the call returns,
@@ -413,7 +412,6 @@ func (o *Order) call(n *Node) {
 			}
 		}
 	}
-	}
 }
 
 // mapAssign appends n to o.out, introducing temporaries
@@ -766,7 +764,9 @@ func (o *Order) stmt(n *Node) {
 			if n2.Ninit.Len() != 0 {
 				Fatalf("order select ninit")
 			}
-			if r != nil {
+			if r == nil {
+				continue
+			}
 			switch r.Op {
 			default:
 				Dump("select case", r)
@@ -870,13 +870,11 @@ func (o *Order) stmt(n *Node) {
 				}
 			}
 		}
-
-			orderBlock(&n2.Nbody)
-		}
 		// Now that we have accumulated all the temporaries, clean them.
 		// Also insert any ninit queued during the previous loop.
 		// (The temporary cleaning must follow that ninit work.)
 		for _, n3 := range n.List.Slice() {
+			orderBlock(&n3.Nbody)
 			n3.Nbody.Prepend(o.cleanTempNoPop(t)...)
 
 			// TODO(mdempsky): Is this actually necessary?

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

@@ -347,10 +347,13 @@ func staticcopy(l *Node, r *Node, out *[]*Node) bool {
 			n.Type = e.Expr.Type
 			if e.Expr.Op == OLITERAL {
 				gdata(n, e.Expr, int(n.Type.Width))
-			} else {
+				continue
+			}
 			ll := n.copy()
 			ll.Orig = ll // completely separate copy
-				if !staticassign(ll, e.Expr, out) {
+			if staticassign(ll, e.Expr, out) {
+				continue
+			}
 			// Requires computation, but we're
 			// copying someone else's computation.
 			rr := orig.copy()
@@ -360,8 +363,6 @@ func staticcopy(l *Node, r *Node, out *[]*Node) bool {
 			setlineno(rr)
 			*out = append(*out, nod(OAS, ll, rr))
 		}
-			}
-		}
 
 		return true
 	}
@@ -449,7 +450,8 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
 			n.Type = e.Expr.Type
 			if e.Expr.Op == OLITERAL {
 				gdata(n, e.Expr, int(n.Type.Width))
-			} else {
+				continue
+			}
 			setlineno(e.Expr)
 			a := n.copy()
 			a.Orig = a // completely separate copy
@@ -457,7 +459,6 @@ func staticassign(l *Node, r *Node, out *[]*Node) bool {
 				*out = append(*out, nod(OAS, a, e.Expr))
 			}
 		}
-		}
 
 		return true
 

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

@@ -3089,7 +3089,8 @@ func typecheckcomplit(n *Node) *Node {
 				if f == nil {
 					if ci := lookdot1(nil, l.Sym, t, t.Fields(), 2); ci != nil { // Case-insensitive lookup.
 						yyerror("unknown field '%v' in struct literal of type %v (but does have %v)", l.Sym, t, ci.Sym)
-					} else {
+						continue
+					}
 					p, _ := dotpath(l.Sym, t, nil, true)
 					if p == nil {
 						yyerror("unknown field '%v' in struct literal of type %v", l.Sym, t)
@@ -3102,7 +3103,6 @@ func typecheckcomplit(n *Node) *Node {
 					}
 					ep = append(ep, l.Sym.Name)
 					yyerror("cannot use promoted field %v in struct literal of type %v", strings.Join(ep, "."), t)
-					}
 					continue
 				}
 				fielddup(f.Sym.Name, hash)