cmd/compile: remove redundant "// fallthrough" comments

Change-Id: Ia3f262f06592b66447c213e2350402cd5e6e2ccd
Reviewed-on: https://go-review.googlesource.com/22389
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

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

@@ -226,16 +226,13 @@ func convlit1(n *Node, t *Type, explicit bool, reuse canReuseNode) *Node {
 	case OCOMPLEX:
 		if n.Type.Etype == TIDEAL {
 			switch t.Etype {
-			// If trying to convert to non-complex type,
-			// leave as complex128 and let typechecker complain.
 			default:
+				// If trying to convert to non-complex type,
+				// leave as complex128 and let typechecker complain.
 				t = Types[TCOMPLEX128]
 				fallthrough
-
-				//fallthrough
 			case TCOMPLEX128:
 				n.Type = t
-
 				n.Left = convlit(n.Left, Types[TFLOAT64])
 				n.Right = convlit(n.Right, Types[TFLOAT64])
 
@@ -711,8 +708,6 @@ func evconst(n *Node) {
 				break
 			}
 			fallthrough
-
-			// fall through
 		case OCONV_ | CTINT_,
 			OCONV_ | CTRUNE_,
 			OCONV_ | CTFLT_,

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

@@ -58,8 +58,6 @@ func anyinit(n []*Node) bool {
 				break
 			}
 			fallthrough
-
-			// fall through
 		default:
 			return true
 		}

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

@@ -342,8 +342,6 @@ func staticcopy(l *Node, r *Node, out *[]*Node) bool {
 			return true
 		}
 		fallthrough
-
-		// fall through
 	case OSTRUCTLIT:
 		p := initplans[r]
 
@@ -1332,8 +1330,6 @@ func iszero(n *Node) bool {
 			break
 		}
 		fallthrough
-
-		// fall through
 	case OSTRUCTLIT:
 		for _, n1 := range n.List.Slice() {
 			if !iszero(n1.Right) {

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

@@ -3153,8 +3153,6 @@ func islvalue(n *Node) bool {
 			return false
 		}
 		fallthrough
-
-		// fall through
 	case OIND, ODOTPTR, OCLOSUREVAR, OPARAM:
 		return true
 
@@ -3858,11 +3856,8 @@ func markbreak(n *Node, implicit *Node) {
 		ORANGE:
 		implicit = n
 		fallthrough
-
-		// fall through
 	default:
 		markbreak(n.Left, implicit)
-
 		markbreak(n.Right, implicit)
 		markbreaklist(n.Ninit, implicit)
 		markbreaklist(n.Nbody, implicit)