cmd/compile: remove Node.Ntest, Node.Stkdelta

$ sizeof -p cmd/compile/internal/gc Node
Node 272
$

Change-Id: I3d9b67eebfc0be0a4b9768d3de3dc76300abd89c
Reviewed-on: https://go-review.googlesource.com/10521Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

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

@@ -134,7 +134,6 @@ func (v *bottomUpVisitor) visitcode(n *Node, min uint32) uint32 {
 	min = v.visitcode(n.Left, min)
 	min = v.visitcode(n.Right, min)
 	min = v.visitcodelist(n.List, min)
-	min = v.visitcode(n.Ntest, min)
 	min = v.visitcodelist(n.Nbody, min)
 	min = v.visitcodelist(n.Rlist, min)
 
@@ -543,7 +542,6 @@ func escloopdepth(e *EscState, n *Node) {
 	escloopdepth(e, n.Left)
 	escloopdepth(e, n.Right)
 	escloopdepthlist(e, n.List)
-	escloopdepth(e, n.Ntest)
 	escloopdepthlist(e, n.Nbody)
 	escloopdepthlist(e, n.Rlist)
 }
@@ -572,7 +570,7 @@ func esc(e *EscState, n *Node, up *Node) {
 	// process type switch as declaration.
 	// must happen before processing of switch body,
 	// so before recursion.
-	if n.Op == OSWITCH && n.Ntest != nil && n.Ntest.Op == OTYPESW {
+	if n.Op == OSWITCH && n.Left != nil && n.Left.Op == OTYPESW {
 		for ll := n.List; ll != nil; ll = ll.Next { // cases
 
 			// ll->n->nname is the variable per case
@@ -597,7 +595,6 @@ func esc(e *EscState, n *Node, up *Node) {
 
 	esc(e, n.Left, n)
 	esc(e, n.Right, n)
-	esc(e, n.Ntest, n)
 	esclist(e, n.Nbody, n)
 	esclist(e, n.List, n)
 	esclist(e, n.Rlist, n)
@@ -646,12 +643,12 @@ func esc(e *EscState, n *Node, up *Node) {
 		}
 
 	case OSWITCH:
-		if n.Ntest != nil && n.Ntest.Op == OTYPESW {
-			for ll := n.List; ll != nil; ll = ll.Next { // cases
-
+		if n.Left != nil && n.Left.Op == OTYPESW {
+			for ll := n.List; ll != nil; ll = ll.Next {
+				// cases
 				// ntest->right is the argument of the .(type),
 				// ll->n->nname is the variable per case
-				escassign(e, ll.N.Nname, n.Ntest.Right)
+				escassign(e, ll.N.Nname, n.Left.Right)
 			}
 		}
 

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

@@ -202,7 +202,6 @@ func reexportdep(n *Node) {
 	reexportdeplist(n.List)
 	reexportdeplist(n.Rlist)
 	reexportdeplist(n.Ninit)
-	reexportdep(n.Ntest)
 	reexportdeplist(n.Nbody)
 }
 

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

@@ -214,7 +214,7 @@ func Jconv(n *Node, flag int) string {
 	}
 
 	if c == 0 && n.Xoffset != BADWIDTH {
-		fmt.Fprintf(&buf, " x(%d%+d)", n.Xoffset, n.Stkdelta)
+		fmt.Fprintf(&buf, " x(%d%+d)", n.Xoffset, stkdelta[n])
 	}
 
 	if n.Class != 0 {
@@ -863,9 +863,9 @@ func stmtfmt(n *Node) string {
 
 	case OIF:
 		if simpleinit {
-			f += fmt.Sprintf("if %v; %v { %v }", n.Ninit.N, n.Ntest, n.Nbody)
+			f += fmt.Sprintf("if %v; %v { %v }", n.Ninit.N, n.Left, n.Nbody)
 		} else {
-			f += fmt.Sprintf("if %v { %v }", n.Ntest, n.Nbody)
+			f += fmt.Sprintf("if %v { %v }", n.Left, n.Nbody)
 		}
 		if n.Rlist != nil {
 			f += fmt.Sprintf(" else { %v }", n.Rlist)
@@ -884,8 +884,8 @@ func stmtfmt(n *Node) string {
 			f += " ;"
 		}
 
-		if n.Ntest != nil {
-			f += fmt.Sprintf(" %v", n.Ntest)
+		if n.Left != nil {
+			f += fmt.Sprintf(" %v", n.Left)
 		}
 
 		if n.Right != nil {
@@ -919,8 +919,8 @@ func stmtfmt(n *Node) string {
 		if simpleinit {
 			f += fmt.Sprintf(" %v;", n.Ninit.N)
 		}
-		if n.Ntest != nil {
-			f += Nconv(n.Ntest, 0)
+		if n.Left != nil {
+			f += Nconv(n.Left, 0)
 		}
 
 		f += fmt.Sprintf(" { %v }", n.List)
@@ -1562,11 +1562,6 @@ func nodedump(n *Node, flag int) string {
 			fmt.Fprintf(&buf, "%v-rlist%v", Oconv(int(n.Op), 0), n.Rlist)
 		}
 
-		if n.Ntest != nil {
-			indent(&buf)
-			fmt.Fprintf(&buf, "%v-test%v", Oconv(int(n.Op), 0), n.Ntest)
-		}
-
 		if n.Nbody != nil {
 			indent(&buf)
 			fmt.Fprintf(&buf, "%v-body%v", Oconv(int(n.Op), 0), n.Nbody)

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

@@ -788,10 +788,10 @@ func gen(n *Node) {
 			lab.Continpc = continpc
 		}
 
-		gen(n.Right)                      // contin:	incr
-		Patch(p1, Pc)                     // test:
-		Bgen(n.Ntest, false, -1, breakpc) //		if(!test) goto break
-		Genlist(n.Nbody)                  //		body
+		gen(n.Right)                     // contin:	incr
+		Patch(p1, Pc)                    // test:
+		Bgen(n.Left, false, -1, breakpc) //		if(!test) goto break
+		Genlist(n.Nbody)                 //		body
 		gjmp(continpc)
 		Patch(breakpc, Pc) // done:
 		continpc = scontin
@@ -802,15 +802,15 @@ func gen(n *Node) {
 		}
 
 	case OIF:
-		p1 := gjmp(nil)                          //		goto test
-		p2 := gjmp(nil)                          // p2:		goto else
-		Patch(p1, Pc)                            // test:
-		Bgen(n.Ntest, false, int(-n.Likely), p2) //		if(!test) goto p2
-		Genlist(n.Nbody)                         //		then
-		p3 := gjmp(nil)                          //		goto done
-		Patch(p2, Pc)                            // else:
-		Genlist(n.Rlist)                         //		else
-		Patch(p3, Pc)                            // done:
+		p1 := gjmp(nil)                         //		goto test
+		p2 := gjmp(nil)                         // p2:		goto else
+		Patch(p1, Pc)                           // test:
+		Bgen(n.Left, false, int(-n.Likely), p2) //		if(!test) goto p2
+		Genlist(n.Nbody)                        //		then
+		p3 := gjmp(nil)                         //		goto done
+		Patch(p2, Pc)                           // else:
+		Genlist(n.Rlist)                        //		else
+		Patch(p3, Pc)                           // done:
 
 	case OSWITCH:
 		sbreak := breakpc

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

@@ -700,14 +700,14 @@ for_header:
 		if $1 != nil {
 			$$.Ninit = list1($1);
 		}
-		$$.Ntest = $3;
+		$$.Left = $3;
 		$$.Right = $5;
 	}
 |	osimple_stmt
 	{
 		// normal test
 		$$ = Nod(OFOR, nil, nil);
-		$$.Ntest = $1;
+		$$.Left = $1;
 	}
 |	range_stmt
 
@@ -734,7 +734,7 @@ if_header:
 	{
 		// test
 		$$ = Nod(OIF, nil, nil);
-		$$.Ntest = $1;
+		$$.Left = $1;
 	}
 |	osimple_stmt ';' osimple_stmt
 	{
@@ -743,7 +743,7 @@ if_header:
 		if $1 != nil {
 			$$.Ninit = list1($1);
 		}
-		$$.Ntest = $3;
+		$$.Left = $3;
 	}
 
 /* IF cond body (ELSE IF cond body)* (ELSE block)? */
@@ -754,7 +754,7 @@ if_stmt:
 	}
 	if_header
 	{
-		if $3.Ntest == nil {
+		if $3.Left == nil {
 			Yyerror("missing condition in if statement");
 		}
 	}
@@ -786,7 +786,7 @@ elseif:
 	}
 	if_header loop_body
 	{
-		if $4.Ntest == nil {
+		if $4.Left == nil {
 			Yyerror("missing condition in if statement");
 		}
 		$4.Nbody = $5;
@@ -821,7 +821,7 @@ switch_stmt:
 	if_header
 	{
 		var n *Node
-		n = $3.Ntest;
+		n = $3.Left;
 		if n != nil && n.Op != OTYPESW {
 			n = nil;
 		}

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

@@ -196,11 +196,11 @@ func fixautoused(p *obj.Prog) {
 		}
 
 		if p.From.Name == obj.NAME_AUTO && p.From.Node != nil {
-			p.From.Offset += ((p.From.Node).(*Node)).Stkdelta
+			p.From.Offset += stkdelta[p.From.Node.(*Node)]
 		}
 
 		if p.To.Name == obj.NAME_AUTO && p.To.Node != nil {
-			p.To.Offset += ((p.To.Node).(*Node)).Stkdelta
+			p.To.Offset += stkdelta[p.To.Node.(*Node)]
 		}
 
 		lp = &p.Link

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

@@ -123,13 +123,13 @@ func fninit(n *NodeList) {
 	// (3)
 	a := Nod(OIF, nil, nil)
 
-	a.Ntest = Nod(ONE, gatevar, Nodintconst(0))
+	a.Left = Nod(ONE, gatevar, Nodintconst(0))
 	r = list(r, a)
 
 	// (4)
 	b := Nod(OIF, nil, nil)
 
-	b.Ntest = Nod(OEQ, gatevar, Nodintconst(2))
+	b.Left = Nod(OEQ, gatevar, Nodintconst(2))
 	b.Nbody = list1(Nod(ORETURN, nil, nil))
 	a.Nbody = list1(b)
 

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

@@ -231,7 +231,7 @@ func ishairy(n *Node, budget *int) bool {
 
 	(*budget)--
 
-	return *budget < 0 || ishairy(n.Left, budget) || ishairy(n.Right, budget) || ishairylist(n.List, budget) || ishairylist(n.Rlist, budget) || ishairylist(n.Ninit, budget) || ishairy(n.Ntest, budget) || ishairylist(n.Nbody, budget)
+	return *budget < 0 || ishairy(n.Left, budget) || ishairy(n.Right, budget) || ishairylist(n.List, budget) || ishairylist(n.Rlist, budget) || ishairylist(n.Ninit, budget) || ishairylist(n.Nbody, budget)
 }
 
 // Inlcopy and inlcopylist recursively copy the body of a function.
@@ -265,7 +265,6 @@ func inlcopy(n *Node) *Node {
 	m.List = inlcopylist(n.List)
 	m.Rlist = inlcopylist(n.Rlist)
 	m.Ninit = inlcopylist(n.Ninit)
-	m.Ntest = inlcopy(n.Ntest)
 	m.Nbody = inlcopylist(n.Nbody)
 
 	return m
@@ -434,11 +433,6 @@ func inlnode(np **Node) {
 		}
 	}
 
-	inlnode(&n.Ntest)
-	if n.Ntest != nil && n.Ntest.Op == OINLCALL {
-		inlconv2expr(&n.Ntest)
-	}
-
 	inlnodelist(n.Nbody)
 	for l := n.Nbody; l != nil; l = l.Next {
 		if l.N.Op == OINLCALL {
@@ -965,7 +959,6 @@ func inlsubst(n *Node) *Node {
 	m.List = inlsubstlist(n.List)
 	m.Rlist = inlsubstlist(n.Rlist)
 	m.Ninit = concat(m.Ninit, inlsubstlist(n.Ninit))
-	m.Ntest = inlsubst(n.Ntest)
 	m.Nbody = inlsubstlist(n.Nbody)
 
 	return m
@@ -993,6 +986,5 @@ func setlno(n *Node, lno int) {
 	setlnolist(n.List, lno)
 	setlnolist(n.Rlist, lno)
 	setlnolist(n.Ninit, lno)
-	setlno(n.Ntest, lno)
 	setlnolist(n.Nbody, lno)
 }

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

@@ -646,7 +646,7 @@ func orderstmt(n *Node, order *Order) {
 	case OFOR:
 		t := marktemp(order)
 
-		orderexprinplace(&n.Ntest, order)
+		orderexprinplace(&n.Left, order)
 		var l *NodeList
 		cleantempnopop(t, order, &l)
 		n.Nbody = concat(l, n.Nbody)
@@ -660,7 +660,7 @@ func orderstmt(n *Node, order *Order) {
 	case OIF:
 		t := marktemp(order)
 
-		orderexprinplace(&n.Ntest, order)
+		orderexprinplace(&n.Left, order)
 		var l *NodeList
 		cleantempnopop(t, order, &l)
 		n.Nbody = concat(l, n.Nbody)
@@ -793,7 +793,7 @@ func orderstmt(n *Node, order *Order) {
 						if t != nil && t.N.Op == ODCL && t.N.Left == r.Left {
 							t = t.Next
 						}
-						if t != nil && t.N.Op == ODCL && t.N.Left == r.Ntest {
+						if t != nil && t.N.Op == ODCL && r.List != nil && t.N.Left == r.List.N {
 							t = t.Next
 						}
 						if t == nil {
@@ -844,19 +844,19 @@ func orderstmt(n *Node, order *Order) {
 						l.N.Ninit = list(l.N.Ninit, tmp2)
 					}
 
-					if r.Ntest != nil && isblank(r.Ntest) {
-						r.Ntest = nil
+					if r.List != nil && isblank(r.List.N) {
+						r.List = nil
 					}
-					if r.Ntest != nil {
-						tmp1 = r.Ntest
+					if r.List != nil {
+						tmp1 = r.List.N
 						if r.Colas {
 							tmp2 = Nod(ODCL, tmp1, nil)
 							typecheck(&tmp2, Etop)
 							l.N.Ninit = list(l.N.Ninit, tmp2)
 						}
 
-						r.Ntest = ordertemp(tmp1.Type, order, false)
-						tmp2 = Nod(OAS, tmp1, r.Ntest)
+						r.List = list1(ordertemp(tmp1.Type, order, false))
+						tmp2 = Nod(OAS, tmp1, r.List.N)
 						typecheck(&tmp2, Etop)
 						l.N.Ninit = list(l.N.Ninit, tmp2)
 					}
@@ -918,7 +918,7 @@ func orderstmt(n *Node, order *Order) {
 	case OSWITCH:
 		t := marktemp(order)
 
-		orderexpr(&n.Ntest, order, nil)
+		orderexpr(&n.Left, order, nil)
 		for l := n.List; l != nil; l = l.Next {
 			if l.N.Op != OXCASE {
 				Fatal("order switch case %v", Oconv(int(l.N.Op), 0))

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

@@ -216,6 +216,11 @@ func cmpstackvar(a *Node, b *Node) int {
 	return stringsCompare(a.Sym.Name, b.Sym.Name)
 }
 
+// stkdelta records the stack offset delta for a node
+// during the compaction of the stack frame to remove
+// unused stack slots.
+var stkdelta = map[*Node]int64{}
+
 // TODO(lvd) find out where the PAUTO/OLITERAL nodes come from.
 func allocauto(ptxt *obj.Prog) {
 	Stksize = 0
@@ -283,7 +288,7 @@ func allocauto(ptxt *obj.Prog) {
 			Yyerror("stack frame too large (>2GB)")
 		}
 
-		n.Stkdelta = -Stksize - n.Xoffset
+		stkdelta[n] = -Stksize - n.Xoffset
 	}
 
 	Stksize = Rnd(Stksize, int64(Widthreg))
@@ -296,8 +301,8 @@ func allocauto(ptxt *obj.Prog) {
 		if ll.N.Class != PAUTO || ll.N.Op != ONAME {
 			continue
 		}
-		ll.N.Xoffset += ll.N.Stkdelta
-		ll.N.Stkdelta = 0
+		ll.N.Xoffset += stkdelta[ll.N]
+		delete(stkdelta, ll.N)
 	}
 }
 

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

@@ -371,18 +371,25 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
 		Yyerror("racewalk: OGETG can happen only in runtime which we don't instrument")
 		goto ret
 
-		// just do generic traversal
 	case OFOR:
+		if n.Left != nil {
+			racewalknode(&n.Left, &n.Left.Ninit, 0, 0)
+		}
 		if n.Right != nil {
 			racewalknode(&n.Right, &n.Right.Ninit, 0, 0)
 		}
 		goto ret
 
-	case OIF,
-		OCALLMETH,
+	case OIF, OSWITCH:
+		if n.Left != nil {
+			racewalknode(&n.Left, &n.Left.Ninit, 0, 0)
+		}
+		goto ret
+
+		// just do generic traversal
+	case OCALLMETH,
 		ORETURN,
 		ORETJMP,
-		OSWITCH,
 		OSELECT,
 		OEMPTY,
 		OBREAK,
@@ -415,9 +422,6 @@ ret:
 	if n.Op != OBLOCK { // OBLOCK is handled above in a special way.
 		racewalklist(n.List, init)
 	}
-	if n.Ntest != nil {
-		racewalknode(&n.Ntest, &n.Ntest.Ninit, 0, 0)
-	}
 	racewalklist(n.Nbody, nil)
 	racewalklist(n.Rlist, nil)
 	*np = n
@@ -577,7 +581,6 @@ func foreach(n *Node, f func(*Node, interface{}), c interface{}) {
 	foreachnode(n.Left, f, c)
 	foreachnode(n.Right, f, c)
 	foreachlist(n.List, f, c)
-	foreachnode(n.Ntest, f, c)
 	foreachlist(n.Nbody, f, c)
 	foreachlist(n.Rlist, f, c)
 }

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

@@ -201,7 +201,7 @@ func walkrange(n *Node) {
 															n.Op = OIF
 
 															n.Nbody = nil
-															n.Ntest = Nod(ONE, Nod(OLEN, a, nil), Nodintconst(0))
+															n.Left = Nod(ONE, Nod(OLEN, a, nil), Nodintconst(0))
 
 															// hp = &a[0]
 															hp := temp(Ptrto(Types[TUINT8]))
@@ -231,7 +231,7 @@ func walkrange(n *Node) {
 
 															n.Nbody = list(n.Nbody, v1)
 
-															typecheck(&n.Ntest, Erv)
+															typecheck(&n.Left, Erv)
 															typechecklist(n.Nbody, Etop)
 															walkstmt(&n)
 															lineno = int32(lno)
@@ -266,7 +266,7 @@ func walkrange(n *Node) {
 			init = list(init, Nod(OAS, hp, Nod(OADDR, tmp, nil)))
 		}
 
-		n.Ntest = Nod(OLT, hv1, hn)
+		n.Left = Nod(OLT, hv1, hn)
 		n.Right = Nod(OAS, hv1, Nod(OADD, hv1, Nodintconst(1)))
 		if v1 == nil {
 			body = nil
@@ -313,7 +313,7 @@ func walkrange(n *Node) {
 
 		substArgTypes(fn, t.Down, t.Type, th)
 		init = list(init, mkcall1(fn, nil, nil, typename(t), ha, Nod(OADDR, hit, nil)))
-		n.Ntest = Nod(ONE, Nod(ODOT, hit, keyname), nodnil())
+		n.Left = Nod(ONE, Nod(ODOT, hit, keyname), nodnil())
 
 		fn = syslook("mapiternext", 1)
 		substArgTypes(fn, th)
@@ -338,7 +338,7 @@ func walkrange(n *Node) {
 	case TCHAN:
 		ha := a
 
-		n.Ntest = nil
+		n.Left = nil
 
 		hv1 := temp(t.Type)
 		hv1.Typecheck = 1
@@ -347,12 +347,12 @@ func walkrange(n *Node) {
 		}
 		hb := temp(Types[TBOOL])
 
-		n.Ntest = Nod(ONE, hb, Nodbool(false))
+		n.Left = Nod(ONE, hb, Nodbool(false))
 		a := Nod(OAS2RECV, nil, nil)
 		a.Typecheck = 1
 		a.List = list(list1(hv1), hb)
 		a.Rlist = list1(Nod(ORECV, ha, nil))
-		n.Ntest.Ninit = list1(a)
+		n.Left.Ninit = list1(a)
 		if v1 == nil {
 			body = nil
 		} else {
@@ -380,8 +380,8 @@ func walkrange(n *Node) {
 			a.Rlist = list1(mkcall1(fn, getoutargx(fn.Type), nil, ha, hv1))
 		}
 
-		n.Ntest = Nod(ONE, hv1, Nodintconst(0))
-		n.Ntest.Ninit = list(list1(Nod(OAS, ohv1, hv1)), a)
+		n.Left = Nod(ONE, hv1, Nodintconst(0))
+		n.Left.Ninit = list(list1(Nod(OAS, ohv1, hv1)), a)
 
 		body = nil
 		if v1 != nil {
@@ -395,8 +395,8 @@ func walkrange(n *Node) {
 	n.Op = OFOR
 	typechecklist(init, Etop)
 	n.Ninit = concat(n.Ninit, init)
-	typechecklist(n.Ntest.Ninit, Etop)
-	typecheck(&n.Ntest, Erv)
+	typechecklist(n.Left.Ninit, Etop)
+	typecheck(&n.Left, Erv)
 	typecheck(&n.Right, Etop)
 	typechecklist(body, Etop)
 	n.Nbody = concat(body, n.Nbody)

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

@@ -65,8 +65,7 @@ func typecheckselect(sel *Node) {
 
 				n.Op = OSELRECV2
 				n.Left = n.List.N
-				n.Ntest = n.List.Next.N
-				n.List = nil
+				n.List = list1(n.List.Next.N)
 				n.Right = n.Rlist.N
 				n.Rlist = nil
 
@@ -131,7 +130,7 @@ func walkselect(sel *Node) {
 
 			case OSELRECV, OSELRECV2:
 				ch = n.Right.Left
-				if n.Op == OSELRECV || n.Ntest == nil {
+				if n.Op == OSELRECV || n.List == nil {
 					if n.Left == nil {
 						n = n.Right
 					} else {
@@ -146,11 +145,10 @@ func walkselect(sel *Node) {
 				}
 
 				n.Op = OAS2
-				n.List = list(list1(n.Left), n.Ntest)
+				n.List = concat(list1(n.Left), n.List)
 				n.Rlist = list1(n.Right)
 				n.Right = nil
 				n.Left = nil
-				n.Ntest = nil
 				n.Typecheck = 0
 				typecheck(&n, Etop)
 			}
@@ -158,7 +156,7 @@ func walkselect(sel *Node) {
 			// if ch == nil { block() }; n;
 			a := Nod(OIF, nil, nil)
 
-			a.Ntest = Nod(OEQ, ch, nodnil())
+			a.Left = Nod(OEQ, ch, nodnil())
 			a.Nbody = list1(mkcall("block", nil, &l))
 			typecheck(&a, Etop)
 			l = list(l, a)
@@ -185,12 +183,12 @@ func walkselect(sel *Node) {
 			typecheck(&n.Right, Erv)
 
 		case OSELRECV, OSELRECV2:
-			if n.Op == OSELRECV2 && n.Ntest == nil {
+			if n.Op == OSELRECV2 && n.List == nil {
 				n.Op = OSELRECV
 			}
 			if n.Op == OSELRECV2 {
-				n.Ntest = Nod(OADDR, n.Ntest, nil)
-				typecheck(&n.Ntest, Erv)
+				n.List.N = Nod(OADDR, n.List.N, nil)
+				typecheck(&n.List.N, Erv)
 			}
 
 			if n.Left == nil {
@@ -226,7 +224,7 @@ func walkselect(sel *Node) {
 		case OSEND:
 			ch := n.Left
 
-			r.Ntest = mkcall1(chanfn("selectnbsend", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), ch, n.Right)
+			r.Left = mkcall1(chanfn("selectnbsend", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), ch, n.Right)
 
 			// if c != nil && selectnbrecv(&v, c) { body } else { default body }
 		case OSELRECV:
@@ -234,7 +232,7 @@ func walkselect(sel *Node) {
 
 			r.Ninit = cas.Ninit
 			ch := n.Right.Left
-			r.Ntest = mkcall1(chanfn("selectnbrecv", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, ch)
+			r.Left = mkcall1(chanfn("selectnbrecv", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, ch)
 
 			// if c != nil && selectnbrecv2(&v, c) { body } else { default body }
 		case OSELRECV2:
@@ -242,10 +240,10 @@ func walkselect(sel *Node) {
 
 			r.Ninit = cas.Ninit
 			ch := n.Right.Left
-			r.Ntest = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, n.Ntest, ch)
+			r.Left = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, n.List.N, ch)
 		}
 
-		typecheck(&r.Ntest, Erv)
+		typecheck(&r.Left, Erv)
 		r.Nbody = cas.Nbody
 		r.Rlist = concat(dflt.Ninit, dflt.Nbody)
 		sel.Nbody = list1(r)
@@ -282,7 +280,7 @@ func walkselect(sel *Node) {
 
 		if n == nil {
 			// selectdefault(sel *byte);
-			r.Ntest = mkcall("selectdefault", Types[TBOOL], &r.Ninit, var_)
+			r.Left = mkcall("selectdefault", Types[TBOOL], &r.Ninit, var_)
 		} else {
 			switch n.Op {
 			default:
@@ -290,15 +288,15 @@ func walkselect(sel *Node) {
 
 				// selectsend(sel *byte, hchan *chan any, elem *any) (selected bool);
 			case OSEND:
-				r.Ntest = mkcall1(chanfn("selectsend", 2, n.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Left, n.Right)
+				r.Left = mkcall1(chanfn("selectsend", 2, n.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Left, n.Right)
 
 				// selectrecv(sel *byte, hchan *chan any, elem *any) (selected bool);
 			case OSELRECV:
-				r.Ntest = mkcall1(chanfn("selectrecv", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left)
+				r.Left = mkcall1(chanfn("selectrecv", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left)
 
 				// selectrecv2(sel *byte, hchan *chan any, elem *any, received *bool) (selected bool);
 			case OSELRECV2:
-				r.Ntest = mkcall1(chanfn("selectrecv2", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left, n.Ntest)
+				r.Left = mkcall1(chanfn("selectrecv2", 2, n.Right.Left.Type), Types[TBOOL], &r.Ninit, var_, n.Right.Left, n.Left, n.List.N)
 			}
 		}
 

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

@@ -214,7 +214,6 @@ func init2(n *Node, out **NodeList) {
 	init1(n, out)
 	init2(n.Left, out)
 	init2(n.Right, out)
-	init2(n.Ntest, out)
 	init2list(n.Ninit, out)
 	init2list(n.List, out)
 	init2list(n.Rlist, out)
@@ -996,7 +995,7 @@ func maplit(ctxt int, n *Node, var_ *Node, init **NodeList) {
 		a.Nbody = list1(r)
 
 		a.Ninit = list1(Nod(OAS, index, Nodintconst(0)))
-		a.Ntest = Nod(OLT, index, Nodintconst(t.Bound))
+		a.Left = Nod(OLT, index, Nodintconst(t.Bound))
 		a.Right = Nod(OAS, index, Nod(OADD, index, Nodintconst(1)))
 
 		typecheck(&a, Etop)
@@ -1221,6 +1220,7 @@ func oaslit(n *Node, init **NodeList) bool {
 	}
 
 	n.Op = OEMPTY
+	n.Right = nil
 	return true
 }
 

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

@@ -2421,7 +2421,7 @@ func genwrapper(rcvr *Type, method *Type, newnam *Sym, iface int) {
 		// generating wrapper from *T to T.
 		n := Nod(OIF, nil, nil)
 
-		n.Ntest = Nod(OEQ, this.Left, nodnil())
+		n.Left = Nod(OEQ, this.Left, nodnil())
 
 		// these strings are already in the reflect tables,
 		// so no space cost to use them here.
@@ -2757,7 +2757,7 @@ func eqfield(p *Node, q *Node, field *Node) *Node {
 	nx := Nod(OXDOT, p, field)
 	ny := Nod(OXDOT, q, field)
 	nif := Nod(OIF, nil, nil)
-	nif.Ntest = Nod(ONE, nx, ny)
+	nif.Left = Nod(ONE, nx, ny)
 	r := Nod(ORETURN, nil, nil)
 	r.List = list(r.List, Nodbool(false))
 	nif.Nbody = list(nif.Nbody, r)
@@ -2802,7 +2802,7 @@ func eqmem(p *Node, q *Node, field *Node, size int64) *Node {
 	}
 
 	nif := Nod(OIF, nil, nil)
-	nif.Ntest = Nod(ONOT, call, nil)
+	nif.Left = Nod(ONOT, call, nil)
 	r := Nod(ORETURN, nil, nil)
 	r.List = list(r.List, Nodbool(false))
 	nif.Nbody = list(nif.Nbody, r)
@@ -2874,7 +2874,7 @@ func geneq(sym *Sym, t *Type) {
 		ny.Bounded = true
 
 		nif := Nod(OIF, nil, nil)
-		nif.Ntest = Nod(ONE, nx, ny)
+		nif.Left = Nod(ONE, nx, ny)
 		r := Nod(ORETURN, nil, nil)
 		r.List = list(r.List, Nodbool(false))
 		nif.Nbody = list(nif.Nbody, r)

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

@@ -66,21 +66,21 @@ func typecheckswitch(n *Node) {
 	var top int
 	var t *Type
 
-	if n.Ntest != nil && n.Ntest.Op == OTYPESW {
+	if n.Left != nil && n.Left.Op == OTYPESW {
 		// type switch
 		top = Etype
-		typecheck(&n.Ntest.Right, Erv)
-		t = n.Ntest.Right.Type
+		typecheck(&n.Left.Right, Erv)
+		t = n.Left.Right.Type
 		if t != nil && t.Etype != TINTER {
-			Yyerror("cannot type switch on non-interface value %v", Nconv(n.Ntest.Right, obj.FmtLong))
+			Yyerror("cannot type switch on non-interface value %v", Nconv(n.Left.Right, obj.FmtLong))
 		}
 	} else {
 		// expression switch
 		top = Erv
-		if n.Ntest != nil {
-			typecheck(&n.Ntest, Erv)
-			defaultlit(&n.Ntest, nil)
-			t = n.Ntest.Type
+		if n.Left != nil {
+			typecheck(&n.Left, Erv)
+			defaultlit(&n.Left, nil)
+			t = n.Left.Type
 		} else {
 			t = Types[TBOOL]
 		}
@@ -88,13 +88,13 @@ func typecheckswitch(n *Node) {
 			var badtype *Type
 			switch {
 			case !okforeq[t.Etype]:
-				Yyerror("cannot switch on %v", Nconv(n.Ntest, obj.FmtLong))
+				Yyerror("cannot switch on %v", Nconv(n.Left, obj.FmtLong))
 			case t.Etype == TARRAY && !Isfixedarray(t):
 				nilonly = "slice"
 			case t.Etype == TARRAY && Isfixedarray(t) && algtype1(t, nil) == ANOEQ:
-				Yyerror("cannot switch on %v", Nconv(n.Ntest, obj.FmtLong))
+				Yyerror("cannot switch on %v", Nconv(n.Left, obj.FmtLong))
 			case t.Etype == TSTRUCT && algtype1(t, &badtype) == ANOEQ:
-				Yyerror("cannot switch on %v (struct containing %v cannot be compared)", Nconv(n.Ntest, obj.FmtLong), badtype)
+				Yyerror("cannot switch on %v (struct containing %v cannot be compared)", Nconv(n.Left, obj.FmtLong), badtype)
 			case t.Etype == TFUNC:
 				nilonly = "func"
 			case t.Etype == TMAP:
@@ -133,13 +133,13 @@ func typecheckswitch(n *Node) {
 					case ll.N.Op == OTYPE:
 						Yyerror("type %v is not an expression", ll.N.Type)
 					case ll.N.Type != nil && assignop(ll.N.Type, t, nil) == 0 && assignop(t, ll.N.Type, nil) == 0:
-						if n.Ntest != nil {
-							Yyerror("invalid case %v in switch on %v (mismatched types %v and %v)", ll.N, n.Ntest, ll.N.Type, t)
+						if n.Left != nil {
+							Yyerror("invalid case %v in switch on %v (mismatched types %v and %v)", ll.N, n.Left, ll.N.Type, t)
 						} else {
 							Yyerror("invalid case %v in switch (mismatched types %v and bool)", ll.N, ll.N.Type)
 						}
 					case nilonly != "" && !Isconst(ll.N, CTNIL):
-						Yyerror("invalid case %v in switch (can only compare %s %v to nil)", ll.N, nilonly, n.Ntest)
+						Yyerror("invalid case %v in switch (can only compare %s %v to nil)", ll.N, nilonly, n.Left)
 					}
 
 				// type switch
@@ -151,12 +151,12 @@ func typecheckswitch(n *Node) {
 					case ll.N.Op != OTYPE && ll.N.Type != nil: // should this be ||?
 						Yyerror("%v is not a type", Nconv(ll.N, obj.FmtLong))
 						// reset to original type
-						ll.N = n.Ntest.Right
+						ll.N = n.Left.Right
 					case ll.N.Type.Etype != TINTER && t.Etype == TINTER && !implements(ll.N.Type, t, &missing, &have, &ptr):
 						if have != nil && missing.Broke == 0 && have.Broke == 0 {
-							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (wrong type for %v method)\n\thave %v%v\n\twant %v%v", Nconv(n.Ntest.Right, obj.FmtLong), ll.N.Type, missing.Sym, have.Sym, Tconv(have.Type, obj.FmtShort), missing.Sym, Tconv(missing.Type, obj.FmtShort))
+							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (wrong type for %v method)\n\thave %v%v\n\twant %v%v", Nconv(n.Left.Right, obj.FmtLong), ll.N.Type, missing.Sym, have.Sym, Tconv(have.Type, obj.FmtShort), missing.Sym, Tconv(missing.Type, obj.FmtShort))
 						} else if missing.Broke == 0 {
-							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (missing %v method)", Nconv(n.Ntest.Right, obj.FmtLong), ll.N.Type, missing.Sym)
+							Yyerror("impossible type switch case: %v cannot have dynamic type %v"+" (missing %v method)", Nconv(n.Left.Right, obj.FmtLong), ll.N.Type, missing.Sym)
 						}
 					}
 				}
@@ -189,22 +189,18 @@ func typecheckswitch(n *Node) {
 // walkswitch walks a switch statement.
 func walkswitch(sw *Node) {
 	// convert switch {...} to switch true {...}
-	if sw.Ntest == nil {
-		sw.Ntest = Nodbool(true)
-		typecheck(&sw.Ntest, Erv)
+	if sw.Left == nil {
+		sw.Left = Nodbool(true)
+		typecheck(&sw.Left, Erv)
 	}
 
-	if sw.Ntest.Op == OTYPESW {
+	if sw.Left.Op == OTYPESW {
 		var s typeSwitch
 		s.walk(sw)
 	} else {
 		var s exprSwitch
 		s.walk(sw)
 	}
-
-	// Discard old AST elements. They can confuse racewalk.
-	sw.Ntest = nil
-	sw.List = nil
 }
 
 // walk generates an AST implementing sw.
@@ -215,15 +211,18 @@ func walkswitch(sw *Node) {
 func (s *exprSwitch) walk(sw *Node) {
 	casebody(sw, nil)
 
+	cond := sw.Left
+	sw.Left = nil
+
 	s.kind = switchKindExpr
-	if Isconst(sw.Ntest, CTBOOL) {
+	if Isconst(cond, CTBOOL) {
 		s.kind = switchKindTrue
-		if !sw.Ntest.Val.U.(bool) {
+		if !cond.Val.U.(bool) {
 			s.kind = switchKindFalse
 		}
 	}
 
-	walkexpr(&sw.Ntest, &sw.Ninit)
+	walkexpr(&cond, &sw.Ninit)
 	t := sw.Type
 	if t == nil {
 		return
@@ -233,17 +232,18 @@ func (s *exprSwitch) walk(sw *Node) {
 	var cas *NodeList
 	if s.kind == switchKindTrue || s.kind == switchKindFalse {
 		s.exprname = Nodbool(s.kind == switchKindTrue)
-	} else if consttype(sw.Ntest) >= 0 {
+	} else if consttype(cond) >= 0 {
 		// leave constants to enable dead code elimination (issue 9608)
-		s.exprname = sw.Ntest
+		s.exprname = cond
 	} else {
-		s.exprname = temp(sw.Ntest.Type)
-		cas = list1(Nod(OAS, s.exprname, sw.Ntest))
+		s.exprname = temp(cond.Type)
+		cas = list1(Nod(OAS, s.exprname, cond))
 		typechecklist(cas, Etop)
 	}
 
 	// enumerate the cases, and lop off the default case
 	cc := caseClauses(sw, s.kind)
+	sw.List = nil
 	var def *Node
 	if len(cc) > 0 && cc[0].typ == caseKindDefault {
 		def = cc[0].node.Right
@@ -278,9 +278,9 @@ func (s *exprSwitch) walk(sw *Node) {
 	if nerrors == 0 {
 		cas = list(cas, def)
 		sw.Nbody = concat(cas, sw.Nbody)
-		sw.List = nil
 		walkstmtlist(sw.Nbody)
 	}
+
 }
 
 // walkCases generates an AST implementing the cases in cc.
@@ -294,14 +294,14 @@ func (s *exprSwitch) walkCases(cc []*caseClause) *Node {
 
 			a := Nod(OIF, nil, nil)
 			if (s.kind != switchKindTrue && s.kind != switchKindFalse) || assignop(n.Left.Type, s.exprname.Type, nil) == OCONVIFACE || assignop(s.exprname.Type, n.Left.Type, nil) == OCONVIFACE {
-				a.Ntest = Nod(OEQ, s.exprname, n.Left) // if name == val
-				typecheck(&a.Ntest, Erv)
+				a.Left = Nod(OEQ, s.exprname, n.Left) // if name == val
+				typecheck(&a.Left, Erv)
 			} else if s.kind == switchKindTrue {
-				a.Ntest = n.Left // if val
+				a.Left = n.Left // if val
 			} else {
 				// s.kind == switchKindFalse
-				a.Ntest = Nod(ONOT, n.Left, nil) // if !val
-				typecheck(&a.Ntest, Erv)
+				a.Left = Nod(ONOT, n.Left, nil) // if !val
+				typecheck(&a.Left, Erv)
 			}
 			a.Nbody = list1(n.Right) // goto l
 
@@ -320,11 +320,11 @@ func (s *exprSwitch) walkCases(cc []*caseClause) *Node {
 		// Search by length and then by value; see exprcmp.
 		lenlt := Nod(OLT, Nod(OLEN, s.exprname, nil), Nod(OLEN, mid, nil))
 		leneq := Nod(OEQ, Nod(OLEN, s.exprname, nil), Nod(OLEN, mid, nil))
-		a.Ntest = Nod(OOROR, lenlt, Nod(OANDAND, leneq, le))
+		a.Left = Nod(OOROR, lenlt, Nod(OANDAND, leneq, le))
 	} else {
-		a.Ntest = le
+		a.Left = le
 	}
-	typecheck(&a.Ntest, Erv)
+	typecheck(&a.Left, Erv)
 	a.Nbody = list1(s.walkCases(cc[:half]))
 	a.Rlist = list1(s.walkCases(cc[half:]))
 	return a
@@ -512,17 +512,21 @@ func caseClauses(sw *Node, kind int) []*caseClause {
 // search using if..goto, although binary search
 // is used with long runs of concrete types.
 func (s *typeSwitch) walk(sw *Node) {
-	if sw.Ntest == nil {
+	cond := sw.Left
+	sw.Left = nil
+
+	if cond == nil {
+		sw.List = nil
 		return
 	}
-	if sw.Ntest.Right == nil {
+	if cond.Right == nil {
 		setlineno(sw)
 		Yyerror("type switch must have an assignment")
 		return
 	}
 
-	walkexpr(&sw.Ntest.Right, &sw.Ninit)
-	if !Istype(sw.Ntest.Right.Type, TINTER) {
+	walkexpr(&cond.Right, &sw.Ninit)
+	if !Istype(cond.Right.Type, TINTER) {
 		Yyerror("type switch must be on an interface")
 		return
 	}
@@ -530,9 +534,9 @@ func (s *typeSwitch) walk(sw *Node) {
 	var cas *NodeList
 
 	// predeclare temporary variables and the boolean var
-	s.facename = temp(sw.Ntest.Right.Type)
+	s.facename = temp(cond.Right.Type)
 
-	a := Nod(OAS, s.facename, sw.Ntest.Right)
+	a := Nod(OAS, s.facename, cond.Right)
 	typecheck(&a, Etop)
 	cas = list(cas, a)
 
@@ -546,7 +550,7 @@ func (s *typeSwitch) walk(sw *Node) {
 	casebody(sw, s.facename)
 
 	// calculate type hash
-	t := sw.Ntest.Right.Type
+	t := cond.Right.Type
 	if isnilinter(t) {
 		a = syslook("efacethash", 1)
 	} else {
@@ -560,6 +564,7 @@ func (s *typeSwitch) walk(sw *Node) {
 	cas = list(cas, a)
 
 	cc := caseClauses(sw, switchKindType)
+	sw.List = nil
 	var def *Node
 	if len(cc) > 0 && cc[0].typ == caseKindDefault {
 		def = cc[0].node.Right
@@ -576,8 +581,8 @@ func (s *typeSwitch) walk(sw *Node) {
 			var v Val
 			v.Ctype = CTNIL
 			a = Nod(OIF, nil, nil)
-			a.Ntest = Nod(OEQ, s.facename, nodlit(v))
-			typecheck(&a.Ntest, Erv)
+			a.Left = Nod(OEQ, s.facename, nodlit(v))
+			typecheck(&a.Left, Erv)
 			a.Nbody = list1(n.Right) // if i==nil { goto l }
 			n.Right = a
 
@@ -658,7 +663,7 @@ func (s *typeSwitch) typeone(t *Node) *Node {
 	init = list(init, a)
 
 	c := Nod(OIF, nil, nil)
-	c.Ntest = s.okname
+	c.Left = s.okname
 	c.Nbody = list1(t.Right) // if ok { goto l }
 
 	return liststmt(list(init, c))
@@ -674,8 +679,8 @@ func (s *typeSwitch) walkCases(cc []*caseClause) *Node {
 				Fatal("typeSwitch walkCases")
 			}
 			a := Nod(OIF, nil, nil)
-			a.Ntest = Nod(OEQ, s.hashname, Nodintconst(int64(c.hash)))
-			typecheck(&a.Ntest, Erv)
+			a.Left = Nod(OEQ, s.hashname, Nodintconst(int64(c.hash)))
+			typecheck(&a.Left, Erv)
 			a.Nbody = list1(n.Right)
 			cas = list(cas, a)
 		}
@@ -685,8 +690,8 @@ func (s *typeSwitch) walkCases(cc []*caseClause) *Node {
 	// find the middle and recur
 	half := len(cc) / 2
 	a := Nod(OIF, nil, nil)
-	a.Ntest = Nod(OLE, s.hashname, Nodintconst(int64(cc[half-1].hash)))
-	typecheck(&a.Ntest, Erv)
+	a.Left = Nod(OLE, s.hashname, Nodintconst(int64(cc[half-1].hash)))
+	typecheck(&a.Left, Erv)
 	a.Nbody = list1(s.walkCases(cc[:half]))
 	a.Rlist = list1(s.walkCases(cc[half:]))
 	return a

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

@@ -15,7 +15,6 @@ type Node struct {
 	// Generic recursive walks should follow these fields.
 	Left  *Node
 	Right *Node
-	Ntest *Node
 	Ninit *NodeList
 	Nbody *NodeList
 	List  *NodeList
@@ -54,8 +53,7 @@ type Node struct {
 	// OLITERAL
 	Val Val
 
-	Xoffset  int64
-	Stkdelta int64 // offset added by stack frame compaction phase.
+	Xoffset int64
 
 	// Escape analysis.
 	Escloopdepth int32 // -1: global, 0: return variables, 1:function top level, increased inside function for every loop or label to mark scopes

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

@@ -237,7 +237,7 @@ func callrecv(n *Node) bool {
 		return true
 	}
 
-	return callrecv(n.Left) || callrecv(n.Right) || callrecv(n.Ntest) || callrecvlist(n.Ninit) || callrecvlist(n.Nbody) || callrecvlist(n.List) || callrecvlist(n.Rlist)
+	return callrecv(n.Left) || callrecv(n.Right) || callrecvlist(n.Ninit) || callrecvlist(n.Nbody) || callrecvlist(n.List) || callrecvlist(n.Rlist)
 }
 
 func callrecvlist(l *NodeList) bool {
@@ -2097,11 +2097,11 @@ OpSwitch:
 		ok |= Etop
 		typechecklist(n.Ninit, Etop)
 		decldepth++
-		typecheck(&n.Ntest, Erv)
-		if n.Ntest != nil {
-			t := n.Ntest.Type
+		typecheck(&n.Left, Erv)
+		if n.Left != nil {
+			t := n.Left.Type
 			if t != nil && t.Etype != TBOOL {
-				Yyerror("non-bool %v used as for condition", Nconv(n.Ntest, obj.FmtLong))
+				Yyerror("non-bool %v used as for condition", Nconv(n.Left, obj.FmtLong))
 			}
 		}
 		typecheck(&n.Right, Etop)
@@ -2112,11 +2112,11 @@ OpSwitch:
 	case OIF:
 		ok |= Etop
 		typechecklist(n.Ninit, Etop)
-		typecheck(&n.Ntest, Erv)
-		if n.Ntest != nil {
-			t := n.Ntest.Type
+		typecheck(&n.Left, Erv)
+		if n.Left != nil {
+			t := n.Left.Type
 			if t != nil && t.Etype != TBOOL {
-				Yyerror("non-bool %v used as if condition", Nconv(n.Ntest, obj.FmtLong))
+				Yyerror("non-bool %v used as if condition", Nconv(n.Left, obj.FmtLong))
 			}
 		}
 		typechecklist(n.Nbody, Etop)
@@ -2811,7 +2811,7 @@ func fielddup(n *Node, hash map[string]bool) {
 	hash[name] = true
 }
 
-func keydup(n *Node, hash []*Node) {
+func keydup(n *Node, hash map[uint32][]*Node) {
 	orign := n
 	if n.Op == OCONVIFACE {
 		n = n.Left
@@ -2846,9 +2846,8 @@ func keydup(n *Node, hash []*Node) {
 		}
 	}
 
-	h := uint(b % uint32(len(hash)))
 	var cmp Node
-	for a := hash[h]; a != nil; a = a.Ntest {
+	for _, a := range hash[b] {
 		cmp.Op = OEQ
 		cmp.Left = n
 		b = 0
@@ -2870,75 +2869,20 @@ func keydup(n *Node, hash []*Node) {
 		}
 	}
 
-	orign.Ntest = hash[h]
-	hash[h] = orign
+	hash[b] = append(hash[b], orign)
 }
 
-func indexdup(n *Node, hash []*Node) {
+func indexdup(n *Node, hash map[int64]*Node) {
 	if n.Op != OLITERAL {
 		Fatal("indexdup: not OLITERAL")
 	}
 
-	b := uint32(Mpgetfix(n.Val.U.(*Mpint)))
-	h := uint(b % uint32(len(hash)))
-	var c uint32
-	for a := hash[h]; a != nil; a = a.Ntest {
-		c = uint32(Mpgetfix(a.Val.U.(*Mpint)))
-		if b == c {
-			Yyerror("duplicate index in array literal: %d", b)
-			return
-		}
-	}
-
-	n.Ntest = hash[h]
-	hash[h] = n
-}
-
-func prime(h uint32, sr uint32) bool {
-	for n := uint32(3); n <= sr; n += 2 {
-		if h%n == 0 {
-			return false
-		}
-	}
-	return true
-}
-
-func inithash(n *Node, autohash []*Node) []*Node {
-	// count the number of entries
-	h := uint32(0)
-
-	for ll := n.List; ll != nil; ll = ll.Next {
-		h++
-	}
-
-	// if the auto hash table is
-	// large enough use it.
-	if h <= uint32(len(autohash)) {
-		for i := range autohash {
-			autohash[i] = nil
-		}
-		return autohash
-	}
-
-	// make hash size odd and 12% larger than entries
-	h += h / 8
-
-	h |= 1
-
-	// calculate sqrt of h
-	sr := h / 2
-
-	for i := 0; i < 5; i++ {
-		sr = (sr + h/sr) / 2
-	}
-
-	// check for primeality
-	for !prime(h, sr) {
-		h += 2
+	v := Mpgetfix(n.Val.U.(*Mpint))
+	if hash[v] != nil {
+		Yyerror("duplicate index in array literal: %d", v)
+		return
 	}
-
-	// build and return a throw-away hash table
-	return make([]*Node, h)
+	hash[v] = n
 }
 
 func iscomptype(t *Type) bool {
@@ -3031,9 +2975,14 @@ func typecheckcomplit(np **Node) {
 		n.Type = nil
 
 	case TARRAY:
-		var autohash [101]*Node
-		hash := inithash(n, autohash[:])
-
+		// Only allocate hash if there are some key/value pairs.
+		var hash map[int64]*Node
+		for ll := n.List; ll != nil; ll = ll.Next {
+			if ll.N.Op == OKEY {
+				hash = make(map[int64]*Node)
+				break
+			}
+		}
 		length := int64(0)
 		i := 0
 		var l *Node
@@ -3056,7 +3005,7 @@ func typecheckcomplit(np **Node) {
 				i = -(1 << 30) // stay negative for a while
 			}
 
-			if i >= 0 {
+			if i >= 0 && hash != nil {
 				indexdup(l.Left, hash)
 			}
 			i++
@@ -3085,9 +3034,7 @@ func typecheckcomplit(np **Node) {
 		n.Op = OARRAYLIT
 
 	case TMAP:
-		var autohash [101]*Node
-		hash := inithash(n, autohash[:])
-
+		hash := make(map[uint32][]*Node)
 		var l *Node
 		for ll := n.List; ll != nil; ll = ll.Next {
 			l = ll.N
@@ -3952,7 +3899,6 @@ func markbreak(n *Node, implicit *Node) {
 		markbreak(n.Left, implicit)
 
 		markbreak(n.Right, implicit)
-		markbreak(n.Ntest, implicit)
 		markbreaklist(n.Ninit, implicit)
 		markbreaklist(n.Nbody, implicit)
 		markbreaklist(n.List, implicit)
@@ -4024,7 +3970,7 @@ func isterminating(l *NodeList, top int) bool {
 		return true
 
 	case OFOR:
-		if n.Ntest != nil {
+		if n.Left != nil {
 			return false
 		}
 		if n.Hasbreak {

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

@@ -247,19 +247,19 @@ func walkstmt(np **Node) {
 		adjustargs(n, 2*Widthptr)
 
 	case OFOR:
-		if n.Ntest != nil {
-			walkstmtlist(n.Ntest.Ninit)
-			init := n.Ntest.Ninit
-			n.Ntest.Ninit = nil
-			walkexpr(&n.Ntest, &init)
-			addinit(&n.Ntest, init)
+		if n.Left != nil {
+			walkstmtlist(n.Left.Ninit)
+			init := n.Left.Ninit
+			n.Left.Ninit = nil
+			walkexpr(&n.Left, &init)
+			addinit(&n.Left, init)
 		}
 
 		walkstmt(&n.Right)
 		walkstmtlist(n.Nbody)
 
 	case OIF:
-		walkexpr(&n.Ntest, &n.Ninit)
+		walkexpr(&n.Left, &n.Ninit)
 		walkstmtlist(n.Nbody)
 		walkstmtlist(n.Rlist)
 
@@ -1043,7 +1043,7 @@ func walkexpr(np **Node, init **NodeList) {
 				walkexpr(&n1, init)
 
 				n2 := Nod(OIF, nil, nil)
-				n2.Ntest = Nod(OEQ, l, nodnil())
+				n2.Left = Nod(OEQ, l, nodnil())
 				n2.Nbody = list1(Nod(OAS, l, n1))
 				n2.Likely = -1
 				typecheck(&n2, Etop)
@@ -2914,7 +2914,7 @@ func appendslice(n *Node, init **NodeList) *Node {
 	// n := len(s) + len(l2) - cap(s)
 	nif.Ninit = list1(Nod(OAS, nt, Nod(OSUB, Nod(OADD, Nod(OLEN, s, nil), Nod(OLEN, l2, nil)), Nod(OCAP, s, nil))))
 
-	nif.Ntest = Nod(OGT, nt, Nodintconst(0))
+	nif.Left = Nod(OGT, nt, Nodintconst(0))
 
 	// instantiate growslice(Type*, []any, int) []any
 	fn := syslook("growslice", 1) //   growslice(<type>, old []T, n int64) (ret []T)
@@ -3046,7 +3046,7 @@ func walkappend(n *Node, init **NodeList, dst *Node) *Node {
 
 	na := Nodintconst(int64(argc)) // const argc
 	nx := Nod(OIF, nil, nil)       // if cap(s) - len(s) < argc
-	nx.Ntest = Nod(OLT, Nod(OSUB, Nod(OCAP, ns, nil), Nod(OLEN, ns, nil)), na)
+	nx.Left = Nod(OLT, Nod(OSUB, Nod(OCAP, ns, nil), Nod(OLEN, ns, nil)), na)
 
 	fn := syslook("growslice", 1) //   growslice(<type>, old []T, n int) (ret []T)
 	substArgTypes(fn, ns.Type.Type, ns.Type.Type)
@@ -3124,7 +3124,7 @@ func copyany(n *Node, init **NodeList, runtimecall int) *Node {
 	// if n > len(frm) { n = len(frm) }
 	nif := Nod(OIF, nil, nil)
 
-	nif.Ntest = Nod(OGT, nlen, Nod(OLEN, nr, nil))
+	nif.Left = Nod(OGT, nlen, Nod(OLEN, nr, nil))
 	nif.Nbody = list(nif.Nbody, Nod(OAS, nlen, Nod(OLEN, nr, nil)))
 	l = list(l, nif)
 
@@ -3982,7 +3982,7 @@ func candiscard(n *Node) bool {
 		return false
 	}
 
-	if !candiscard(n.Left) || !candiscard(n.Right) || !candiscard(n.Ntest) || !candiscardlist(n.Ninit) || !candiscardlist(n.Nbody) || !candiscardlist(n.List) || !candiscardlist(n.Rlist) {
+	if !candiscard(n.Left) || !candiscard(n.Right) || !candiscardlist(n.Ninit) || !candiscardlist(n.Nbody) || !candiscardlist(n.List) || !candiscardlist(n.Rlist) {
 		return false
 	}
 

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

@@ -1788,7 +1788,7 @@ yydefault:
 			if yyDollar[1].node != nil {
 				yyVAL.node.Ninit = list1(yyDollar[1].node)
 			}
-			yyVAL.node.Ntest = yyDollar[3].node
+			yyVAL.node.Left = yyDollar[3].node
 			yyVAL.node.Right = yyDollar[5].node
 		}
 	case 71:
@@ -1797,7 +1797,7 @@ yydefault:
 		{
 			// normal test
 			yyVAL.node = Nod(OFOR, nil, nil)
-			yyVAL.node.Ntest = yyDollar[1].node
+			yyVAL.node.Left = yyDollar[1].node
 		}
 	case 73:
 		yyDollar = yyS[yypt-2 : yypt+1]
@@ -1825,7 +1825,7 @@ yydefault:
 		{
 			// test
 			yyVAL.node = Nod(OIF, nil, nil)
-			yyVAL.node.Ntest = yyDollar[1].node
+			yyVAL.node.Left = yyDollar[1].node
 		}
 	case 77:
 		yyDollar = yyS[yypt-3 : yypt+1]
@@ -1836,7 +1836,7 @@ yydefault:
 			if yyDollar[1].node != nil {
 				yyVAL.node.Ninit = list1(yyDollar[1].node)
 			}
-			yyVAL.node.Ntest = yyDollar[3].node
+			yyVAL.node.Left = yyDollar[3].node
 		}
 	case 78:
 		yyDollar = yyS[yypt-1 : yypt+1]
@@ -1848,7 +1848,7 @@ yydefault:
 		yyDollar = yyS[yypt-3 : yypt+1]
 		//line go.y:756
 		{
-			if yyDollar[3].node.Ntest == nil {
+			if yyDollar[3].node.Left == nil {
 				Yyerror("missing condition in if statement")
 			}
 		}
@@ -1886,7 +1886,7 @@ yydefault:
 		yyDollar = yyS[yypt-5 : yypt+1]
 		//line go.y:788
 		{
-			if yyDollar[4].node.Ntest == nil {
+			if yyDollar[4].node.Left == nil {
 				Yyerror("missing condition in if statement")
 			}
 			yyDollar[4].node.Nbody = yyDollar[5].list
@@ -1929,7 +1929,7 @@ yydefault:
 		//line go.y:822
 		{
 			var n *Node
-			n = yyDollar[3].node.Ntest
+			n = yyDollar[3].node.Left
 			if n != nil && n.Op != OTYPESW {
 				n = nil
 			}