[dev.regabi] cmd/compile: remove typ from RangeStmt

We can use RangeStmt.X.Type() instead.

Passes buildall w/ toolstash -cmp.

Change-Id: Id63ce9cb046c3b39bcc35453b1602c986794dfe1
Reviewed-on: https://go-review.googlesource.com/c/go/+/279437
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/ir/stmt.go

@@ -300,7 +300,6 @@ type RangeStmt struct {
 	Value    Node
 	Body     Nodes
 	HasBreak bool
-	typ      *types.Type // TODO(rsc): Remove - use X.Type() instead
 	Prealloc *Name
 }
 
@@ -312,9 +311,6 @@ func NewRangeStmt(pos src.XPos, key, value, x Node, body []Node) *RangeStmt {
 	return n
 }
 
-func (n *RangeStmt) Type() *types.Type     { return n.typ }
-func (n *RangeStmt) SetType(x *types.Type) { n.typ = x }
-
 // A ReturnStmt is a return statement.
 type ReturnStmt struct {
 	miniStmt

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

@@ -11,13 +11,20 @@ import (
 	"cmd/internal/src"
 )
 
+func RangeExprType(t *types.Type) *types.Type {
+	if t.IsPtr() && t.Elem().IsArray() {
+		return t.Elem()
+	}
+	return t
+}
+
 func typecheckrangeExpr(n *ir.RangeStmt) {
 	n.X = Expr(n.X)
-
-	t := n.X.Type()
-	if t == nil {
+	if n.X.Type() == nil {
 		return
 	}
+
+	t := RangeExprType(n.X.Type())
 	// delicate little dance.  see typecheckas2
 	if n.Key != nil && !ir.DeclaredBy(n.Key, n) {
 		n.Key = AssignExpr(n.Key)
@@ -25,10 +32,6 @@ func typecheckrangeExpr(n *ir.RangeStmt) {
 	if n.Value != nil && !ir.DeclaredBy(n.Value, n) {
 		n.Value = AssignExpr(n.Value)
 	}
-	if t.IsPtr() && t.Elem().IsArray() {
-		t = t.Elem()
-	}
-	n.SetType(t)
 
 	var tk, tv *types.Type
 	toomany := false

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

@@ -843,7 +843,8 @@ func (o *orderState) stmt(n ir.Node) {
 		n.X = o.expr(n.X, nil)
 
 		orderBody := true
-		switch n.Type().Kind() {
+		xt := typecheck.RangeExprType(n.X.Type())
+		switch xt.Kind() {
 		default:
 			base.Fatalf("order.stmt range %v", n.Type())
 
@@ -885,7 +886,7 @@ func (o *orderState) stmt(n ir.Node) {
 
 			// n.Prealloc is the temp for the iterator.
 			// hiter contains pointers and needs to be zeroed.
-			n.Prealloc = o.newTemp(reflectdata.MapIterType(n.Type()), true)
+			n.Prealloc = o.newTemp(reflectdata.MapIterType(xt), true)
 		}
 		n.Key = o.exprInPlace(n.Key)
 		n.Value = o.exprInPlace(n.Value)

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

@@ -56,9 +56,8 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 	//	hb: hidden bool
 	//	a, v1, v2: not hidden aggregate, val 1, 2
 
-	t := nrange.Type()
-
 	a := nrange.X
+	t := typecheck.RangeExprType(a.Type())
 	lno := ir.SetPos(a)
 
 	v1, v2 := nrange.Key, nrange.Value
@@ -113,7 +112,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		}
 
 		// for v1, v2 := range ha { body }
-		if cheapComputableIndex(nrange.Type().Elem().Width) {
+		if cheapComputableIndex(t.Elem().Width) {
 			// v1, v2 = hv1, ha[hv1]
 			tmp := ir.NewIndexExpr(base.Pos, ha, hv1)
 			tmp.SetBounded(true)
@@ -142,7 +141,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node {
 		ifGuard.Cond = ir.NewBinaryExpr(base.Pos, ir.OLT, hv1, hn)
 		nfor.SetOp(ir.OFORUNTIL)
 
-		hp := typecheck.Temp(types.NewPtr(nrange.Type().Elem()))
+		hp := typecheck.Temp(types.NewPtr(t.Elem()))
 		tmp := ir.NewIndexExpr(base.Pos, ha, ir.NewInt(0))
 		tmp.SetBounded(true)
 		init = append(init, ir.NewAssignStmt(base.Pos, hp, typecheck.NodAddr(tmp)))
@@ -335,7 +334,8 @@ func isMapClear(n *ir.RangeStmt) bool {
 		return false
 	}
 
-	if n.Op() != ir.ORANGE || n.Type().Kind() != types.TMAP || n.Key == nil || n.Value != nil {
+	t := n.X.Type()
+	if n.Op() != ir.ORANGE || t.Kind() != types.TMAP || n.Key == nil || n.Value != nil {
 		return false
 	}
 
@@ -360,7 +360,7 @@ func isMapClear(n *ir.RangeStmt) bool {
 	}
 
 	// Keys where equality is not reflexive can not be deleted from maps.
-	if !types.IsReflexive(m.Type().Key()) {
+	if !types.IsReflexive(t.Key()) {
 		return false
 	}
 
@@ -416,7 +416,7 @@ func arrayClear(loop *ir.RangeStmt, v1, v2, a ir.Node) ir.Node {
 		return nil
 	}
 
-	elemsize := loop.Type().Elem().Width
+	elemsize := typecheck.RangeExprType(loop.X.Type()).Elem().Width
 	if elemsize <= 0 || !ir.IsZero(stmt.Y) {
 		return nil
 	}