cmd/compile: simplify a few early var declarations

These were likely written in C or added by an automated tool. Either
way, they're unnecessary now. Clean up the code.

Change-Id: I56de2c7bb60ebab8c500803a8b6586bdf4bf75c7
Reviewed-on: https://go-review.googlesource.com/62951
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

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

@@ -113,15 +113,12 @@ func paramoutheap(fn *Node) bool {
 // adds "adjust" to all the argument locations for the call n.
 // n must be a defer or go node that has already been walked.
 func adjustargs(n *Node, adjust int) {
-	var arg *Node
-	var lhs *Node
-
 	callfunc := n.Left
-	for _, arg = range callfunc.List.Slice() {
+	for _, arg := range callfunc.List.Slice() {
 		if arg.Op != OAS {
 			Fatalf("call arg not assignment")
 		}
-		lhs = arg.Left
+		lhs := arg.Left
 		if lhs.Op == ONAME {
 			// This is a temporary introduced by reorder1.
 			// The real store to the stack appears later in the arg list.
@@ -303,9 +300,8 @@ func walkstmt(n *Node) *Node {
 			// so that reorder3 can fix up conflicts
 			var rl []*Node
 
-			var cl Class
 			for _, ln := range Curfn.Func.Dcl {
-				cl = ln.Class()
+				cl := ln.Class()
 				if cl == PAUTO || cl == PAUTOHEAP {
 					break
 				}
@@ -2367,7 +2363,6 @@ func reorder1(all []*Node) []*Node {
 	var f *Node   // last fncall assigned to stack
 	var r []*Node // non fncalls and tempnames assigned to stack
 	d := 0
-	var a *Node
 	for _, n := range all {
 		if !n.HasCall() {
 			r = append(r, n)
@@ -2381,7 +2376,7 @@ func reorder1(all []*Node) []*Node {
 		}
 
 		// make assignment of fncall to tempname
-		a = temp(n.Right.Type)
+		a := temp(n.Right.Type)
 
 		a = nod(OAS, a, n.Right)
 		g = append(g, a)
@@ -2406,8 +2401,6 @@ func reorder1(all []*Node) []*Node {
 //
 // function calls have been removed.
 func reorder3(all []*Node) []*Node {
-	var l *Node
-
 	// If a needed expression may be affected by an
 	// earlier assignment, make an early copy of that
 	// expression and use the copy instead.
@@ -2415,7 +2408,7 @@ func reorder3(all []*Node) []*Node {
 
 	var mapinit Nodes
 	for i, n := range all {
-		l = n.Left
+		l := n.Left
 
 		// Save subexpressions needed on left side.
 		// Drill through non-dereferences.
@@ -2522,9 +2515,8 @@ func aliased(n *Node, all []*Node, i int) bool {
 	memwrite := 0
 
 	varwrite := 0
-	var a *Node
 	for _, an := range all[:i] {
-		a = outervalue(an.Left)
+		a := outervalue(an.Left)
 
 		for a.Op == ODOT {
 			a = a.Left
@@ -3915,12 +3907,10 @@ func walkprintfunc(n *Node, init *Nodes) *Node {
 	t := nod(OTFUNC, nil, nil)
 	num := 0
 	var printargs []*Node
-	var a *Node
-	var buf string
 	for _, n1 := range n.List.Slice() {
-		buf = fmt.Sprintf("a%d", num)
+		buf := fmt.Sprintf("a%d", num)
 		num++
-		a = namedfield(buf, n1.Type)
+		a := namedfield(buf, n1.Type)
 		t.List.Append(a)
 		printargs = append(printargs, a.Left)
 	}
@@ -3932,7 +3922,7 @@ func walkprintfunc(n *Node, init *Nodes) *Node {
 	sym := lookupN("print·%d", walkprintfunc_prgen)
 	fn := dclfunc(sym, t)
 
-	a = nod(n.Op, nil, nil)
+	a := nod(n.Op, nil, nil)
 	a.List.Set(printargs)
 	a = typecheck(a, Etop)
 	a = walkstmt(a)