[dev.cc] cmd/internal/obj, cmd/internal/gc, new6g: reconvert

Reconvert using rsc.io/c2go rev 27b3f59.

Changes to converter:
 - fatal does not return, so no fallthrough after fatal in switch
 - many more function results and variables identified as bool
 - simplification of negated boolean expressions

Change-Id: I3bc67da5e46cb7ee613e230cf7e9533036cc870b
Reviewed-on: https://go-review.googlesource.com/5171Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

src/cmd/internal/gc/align.go

@@ -138,7 +138,7 @@ func dowidth(t *Type) {
 	if t.Width == -2 {
 		lno = int(lineno)
 		lineno = int32(t.Lineno)
-		if !(t.Broke != 0) {
+		if t.Broke == 0 {
 			t.Broke = 1
 			Yyerror("invalid recursive type %v", Tconv(t, 0))
 		}
@@ -253,14 +253,14 @@ func dowidth(t *Type) {
 		checkwidth(t.Down)
 
 	case TFORW: // should have been filled in
-		if !(t.Broke != 0) {
+		if t.Broke == 0 {
 			Yyerror("invalid recursive type %v", Tconv(t, 0))
 		}
 		w = 1 // anything will do
 
 		// dummy type; should be replaced before use.
 	case TANY:
-		if !(Debug['A'] != 0) {
+		if Debug['A'] == 0 {
 			Fatal("dowidth any")
 		}
 		w = 1 // anything will do
@@ -294,7 +294,7 @@ func dowidth(t *Type) {
 			checkwidth(t.Type)
 			t.Align = uint8(Widthptr)
 		} else if t.Bound == -100 {
-			if !(t.Broke != 0) {
+			if t.Broke == 0 {
 				Yyerror("use of [...] array outside of array literal")
 				t.Broke = 1
 			}
@@ -394,7 +394,7 @@ func checkwidth(t *Type) {
 		Fatal("checkwidth %v", Tconv(t, 0))
 	}
 
-	if !(defercalc != 0) {
+	if defercalc == 0 {
 		dowidth(t)
 		return
 	}
@@ -427,7 +427,7 @@ func defercheckwidth() {
 func resumecheckwidth() {
 	var l *TypeList
 
-	if !(defercalc != 0) {
+	if defercalc == 0 {
 		Fatal("resumecheckwidth")
 	}
 	for l = tlq; l != nil; l = tlq {

src/cmd/internal/gc/bits.go

@@ -66,15 +66,15 @@ bnot(Bits a)
 	return c;
 }
 */
-func bany(a *Bits) int {
+func bany(a *Bits) bool {
 	var i int
 
 	for i = 0; i < BITS; i++ {
 		if a.b[i] != 0 {
-			return 1
+			return true
 		}
 	}
-	return 0
+	return false
 }
 
 /*
@@ -112,8 +112,8 @@ func blsh(n uint) Bits {
 	return c
 }
 
-func btest(a *Bits, n uint) int {
-	return bool2int(a.b[n/64]&(1<<(n%64)) != 0)
+func btest(a *Bits, n uint) bool {
+	return a.b[n/64]&(1<<(n%64)) != 0
 }
 
 func biset(a *Bits, n uint) {
@@ -144,7 +144,7 @@ func Qconv(bits Bits, flag int) string {
 
 	first = 1
 
-	for bany(&bits) != 0 {
+	for bany(&bits) {
 		i = bnum(bits)
 		if first != 0 {
 			first = 0

src/cmd/internal/gc/bv.go

@@ -120,15 +120,15 @@ func bvnext(bv *Bvec, i int32) int {
 	return int(i)
 }
 
-func bvisempty(bv *Bvec) int {
+func bvisempty(bv *Bvec) bool {
 	var i int32
 
 	for i = 0; i < bv.n; i += WORDBITS {
 		if bv.b[i>>WORDSHIFT] != 0 {
-			return 0
+			return false
 		}
 	}
-	return 1
+	return true
 }
 
 func bvnot(bv *Bvec) {

src/cmd/internal/gc/closure.go

@@ -91,7 +91,7 @@ func typecheckclosure(func_ *Node, top int) {
 
 	for l = func_.Cvars; l != nil; l = l.Next {
 		n = l.N.Closure
-		if !(n.Captured != 0) {
+		if n.Captured == 0 {
 			n.Captured = 1
 			if n.Decldepth == 0 {
 				Fatal("typecheckclosure: var %v does not have decldepth assigned", Nconv(n, obj.FmtShort))
@@ -218,7 +218,7 @@ func capturevars(xfunc *Node) {
 		v.Outerexpr = nil
 
 		// out parameters will be assigned to implicitly upon return.
-		if outer.Class != PPARAMOUT && !(v.Closure.Addrtaken != 0) && !(v.Closure.Assigned != 0) && v.Type.Width <= 128 {
+		if outer.Class != PPARAMOUT && v.Closure.Addrtaken == 0 && v.Closure.Assigned == 0 && v.Type.Width <= 128 {
 			v.Byval = 1
 		} else {
 			v.Closure.Addrtaken = 1
@@ -351,7 +351,7 @@ func transformclosure(xfunc *Node) {
 			cv = Nod(OCLOSUREVAR, nil, nil)
 
 			cv.Type = v.Type
-			if !(v.Byval != 0) {
+			if v.Byval == 0 {
 				cv.Type = Ptrto(v.Type)
 			}
 			offset = Rnd(offset, int64(cv.Type.Align))
@@ -389,7 +389,7 @@ func transformclosure(xfunc *Node) {
 		typechecklist(body, Etop)
 		walkstmtlist(body)
 		xfunc.Enter = body
-		xfunc.Needctxt = uint8(bool2int(nvar > 0))
+		xfunc.Needctxt = nvar > 0
 	}
 
 	lineno = int32(lno)
@@ -430,7 +430,7 @@ func walkclosure(func_ *Node, init **NodeList) *Node {
 			continue
 		}
 		typ1 = typenod(v.Type)
-		if !(v.Byval != 0) {
+		if v.Byval == 0 {
 			typ1 = Nod(OIND, typ1, nil)
 		}
 		typ.List = list(typ.List, Nod(ODCLFIELD, newname(v.Sym), typ1))
@@ -594,7 +594,7 @@ func makepartialcall(fn *Node, t0 *Type, meth *Node) *Node {
 	// Declare and initialize variable holding receiver.
 	body = nil
 
-	xfunc.Needctxt = 1
+	xfunc.Needctxt = true
 	cv = Nod(OCLOSUREVAR, nil, nil)
 	cv.Xoffset = int64(Widthptr)
 	cv.Type = rcvrtype
@@ -609,7 +609,7 @@ func makepartialcall(fn *Node, t0 *Type, meth *Node) *Node {
 	ptr.Used = 1
 	ptr.Curfn = xfunc
 	xfunc.Dcl = list(xfunc.Dcl, ptr)
-	if Isptr[rcvrtype.Etype] != 0 || Isinter(rcvrtype) != 0 {
+	if Isptr[rcvrtype.Etype] != 0 || Isinter(rcvrtype) {
 		ptr.Ntype = typenod(rcvrtype)
 		body = list(body, Nod(OAS, ptr, cv))
 	} else {
@@ -652,7 +652,7 @@ func walkpartialcall(n *Node, init **NodeList) *Node {
 	//
 	// Like walkclosure above.
 
-	if Isinter(n.Left.Type) != 0 {
+	if Isinter(n.Left.Type) {
 		// Trigger panic for method on nil interface now.
 		// Otherwise it happens in the wrapper and is confusing.
 		n.Left = cheapexpr(n.Left, init)

src/cmd/internal/gc/cplx.go

@@ -10,12 +10,12 @@ func CASE(a int, b int) int {
 	return a<<16 | b
 }
 
-func overlap_cplx(f *Node, t *Node) int {
+func overlap_cplx(f *Node, t *Node) bool {
 	// check whether f and t could be overlapping stack references.
 	// not exact, because it's hard to check for the stack register
 	// in portable code.  close enough: worst case we will allocate
 	// an extra temporary and the registerizer will clean it up.
-	return bool2int(f.Op == OINDREG && t.Op == OINDREG && f.Xoffset+f.Type.Width >= t.Xoffset && t.Xoffset+t.Type.Width >= f.Xoffset)
+	return f.Op == OINDREG && t.Op == OINDREG && f.Xoffset+f.Type.Width >= t.Xoffset && t.Xoffset+t.Type.Width >= f.Xoffset
 }
 
 func Complexbool(op int, nl *Node, nr *Node, true_ bool, likely int, to *obj.Prog) {
@@ -31,20 +31,20 @@ func Complexbool(op int, nl *Node, nr *Node, true_ bool, likely int, to *obj.Pro
 
 	// make both sides addable in ullman order
 	if nr != nil {
-		if nl.Ullman > nr.Ullman && !(nl.Addable != 0) {
+		if nl.Ullman > nr.Ullman && nl.Addable == 0 {
 			Tempname(&tnl, nl.Type)
 			Thearch.Cgen(nl, &tnl)
 			nl = &tnl
 		}
 
-		if !(nr.Addable != 0) {
+		if nr.Addable == 0 {
 			Tempname(&tnr, nr.Type)
 			Thearch.Cgen(nr, &tnr)
 			nr = &tnr
 		}
 	}
 
-	if !(nl.Addable != 0) {
+	if nl.Addable == 0 {
 		Tempname(&tnl, nl.Type)
 		Thearch.Cgen(nl, &tnl)
 		nl = &tnl
@@ -87,7 +87,7 @@ func subnode(nr *Node, ni *Node, nc *Node) {
 	var tc int
 	var t *Type
 
-	if !(nc.Addable != 0) {
+	if nc.Addable == 0 {
 		Fatal("subnode not addable")
 	}
 
@@ -243,7 +243,7 @@ func nodfconst(n *Node, t *Type, fval *Mpflt) {
 	n.Val.Ctype = CTFLT
 	n.Type = t
 
-	if !(Isfloat[t.Etype] != 0) {
+	if Isfloat[t.Etype] == 0 {
 		Fatal("nodfconst: bad type %v", Tconv(t, 0))
 	}
 }
@@ -251,7 +251,7 @@ func nodfconst(n *Node, t *Type, fval *Mpflt) {
 /*
  * cplx.c
  */
-func Complexop(n *Node, res *Node) int {
+func Complexop(n *Node, res *Node) bool {
 	if n != nil && n.Type != nil {
 		if Iscomplex[n.Type.Etype] != 0 {
 			goto maybe
@@ -292,11 +292,11 @@ maybe:
 
 	//dump("\ncomplex-no", n);
 no:
-	return 0
+	return false
 
 	//dump("\ncomplex-yes", n);
 yes:
-	return 1
+	return true
 }
 
 func Complexmove(f *Node, t *Node) {
@@ -313,7 +313,7 @@ func Complexmove(f *Node, t *Node) {
 		Dump("complexmove-t", t)
 	}
 
-	if !(t.Addable != 0) {
+	if t.Addable == 0 {
 		Fatal("complexmove: to not addable")
 	}
 
@@ -322,7 +322,6 @@ func Complexmove(f *Node, t *Node) {
 	switch uint32(ft)<<16 | uint32(tt) {
 	default:
 		Fatal("complexmove: unknown conversion: %v -> %v\n", Tconv(f.Type, 0), Tconv(t.Type, 0))
-		fallthrough
 
 		// complex to complex move/convert.
 	// make f addable.
@@ -331,7 +330,7 @@ func Complexmove(f *Node, t *Node) {
 		TCOMPLEX64<<16 | TCOMPLEX128,
 		TCOMPLEX128<<16 | TCOMPLEX64,
 		TCOMPLEX128<<16 | TCOMPLEX128:
-		if !(f.Addable != 0) || overlap_cplx(f, t) != 0 {
+		if f.Addable == 0 || overlap_cplx(f, t) {
 			Tempname(&tmp, f.Type)
 			Complexmove(f, &tmp)
 			f = &tmp
@@ -380,7 +379,7 @@ func Complexgen(n *Node, res *Node) {
 	case OREAL,
 		OIMAG:
 		nl = n.Left
-		if !(nl.Addable != 0) {
+		if nl.Addable == 0 {
 			Tempname(&tmp, nl.Type)
 			Complexgen(nl, &tmp)
 			nl = &tmp
@@ -403,7 +402,7 @@ func Complexgen(n *Node, res *Node) {
 	tr = Simsimtype(n.Type)
 	tr = cplxsubtype(tr)
 	if tl != tr {
-		if !(n.Addable != 0) {
+		if n.Addable == 0 {
 			Tempname(&n1, n.Type)
 			Complexmove(n, &n1)
 			n = &n1
@@ -413,7 +412,7 @@ func Complexgen(n *Node, res *Node) {
 		return
 	}
 
-	if !(res.Addable != 0) {
+	if res.Addable == 0 {
 		Thearch.Igen(res, &n1, nil)
 		Thearch.Cgen(n, &n1)
 		Thearch.Regfree(&n1)
@@ -429,7 +428,6 @@ func Complexgen(n *Node, res *Node) {
 	default:
 		Dump("complexgen: unknown op", n)
 		Fatal("complexgen: unknown op %v", Oconv(int(n.Op), 0))
-		fallthrough
 
 	case ODOT,
 		ODOTPTR,
@@ -464,20 +462,20 @@ func Complexgen(n *Node, res *Node) {
 
 	// make both sides addable in ullman order
 	if nr != nil {
-		if nl.Ullman > nr.Ullman && !(nl.Addable != 0) {
+		if nl.Ullman > nr.Ullman && nl.Addable == 0 {
 			Tempname(&tnl, nl.Type)
 			Thearch.Cgen(nl, &tnl)
 			nl = &tnl
 		}
 
-		if !(nr.Addable != 0) {
+		if nr.Addable == 0 {
 			Tempname(&tnr, nr.Type)
 			Thearch.Cgen(nr, &tnr)
 			nr = &tnr
 		}
 	}
 
-	if !(nl.Addable != 0) {
+	if nl.Addable == 0 {
 		Tempname(&tnl, nl.Type)
 		Thearch.Cgen(nl, &tnl)
 		nl = &tnl

src/cmd/internal/gc/dcl.go

@@ -10,17 +10,17 @@ import (
 	"strings"
 )
 
-func dflag() int {
-	if !(Debug['d'] != 0) {
-		return 0
+func dflag() bool {
+	if Debug['d'] == 0 {
+		return false
 	}
 	if Debug['y'] != 0 {
-		return 1
+		return true
 	}
 	if incannedimport != 0 {
-		return 0
+		return false
 	}
-	return 1
+	return true
 }
 
 /*
@@ -49,7 +49,7 @@ func pushdcl(s *Sym) *Sym {
 
 	d = push()
 	dcopy(d, s)
-	if dflag() != 0 {
+	if dflag() {
 		fmt.Printf("\t%v push %v %p\n", Ctxt.Line(int(lineno)), Sconv(s, 0), s.Def)
 	}
 	return d
@@ -71,7 +71,7 @@ func popdcl() {
 		lno = int(s.Lastlineno)
 		dcopy(s, d)
 		d.Lastlineno = int32(lno)
-		if dflag() != 0 {
+		if dflag() {
 			fmt.Printf("\t%v pop %v %p\n", Ctxt.Line(int(lineno)), Sconv(s, 0), s.Def)
 		}
 	}
@@ -195,7 +195,7 @@ func declare(n *Node, ctxt int) {
 	s = n.Sym
 
 	// kludgy: typecheckok means we're past parsing.  Eg genwrapper may declare out of package names later.
-	if importpkg == nil && !(typecheckok != 0) && s.Pkg != localpkg {
+	if importpkg == nil && typecheckok == 0 && s.Pkg != localpkg {
 		Yyerror("cannot declare name %v", Sconv(s, 0))
 	}
 
@@ -206,7 +206,7 @@ func declare(n *Node, ctxt int) {
 	gen = 0
 	if ctxt == PEXTERN {
 		externdcl = list(externdcl, n)
-		if dflag() != 0 {
+		if dflag() {
 			fmt.Printf("\t%v global decl %v %p\n", Ctxt.Line(int(lineno)), Sconv(s, 0), n)
 		}
 	} else {
@@ -264,14 +264,14 @@ func addvar(n *Node, t *Type, ctxt int) {
  * new_name_list (type | [type] = expr_list)
  */
 func variter(vl *NodeList, t *Node, el *NodeList) *NodeList {
-	var doexpr int
+	var doexpr bool
 	var v *Node
 	var e *Node
 	var as2 *Node
 	var init *NodeList
 
 	init = nil
-	doexpr = bool2int(el != nil)
+	doexpr = el != nil
 
 	if count(el) == 1 && count(vl) > 1 {
 		e = el.N
@@ -293,7 +293,7 @@ func variter(vl *NodeList, t *Node, el *NodeList) *NodeList {
 	}
 
 	for ; vl != nil; vl = vl.Next {
-		if doexpr != 0 {
+		if doexpr {
 			if el == nil {
 				Yyerror("missing expression in var declaration")
 				break
@@ -479,17 +479,17 @@ func oldname(s *Sym) *Node {
 /*
  * := declarations
  */
-func colasname(n *Node) int {
+func colasname(n *Node) bool {
 	switch n.Op {
 	case ONAME,
 		ONONAME,
 		OPACK,
 		OTYPE,
 		OLITERAL:
-		return bool2int(n.Sym != nil)
+		return n.Sym != nil
 	}
 
-	return 0
+	return false
 }
 
 func colasdefn(left *NodeList, defn *Node) {
@@ -511,7 +511,7 @@ func colasdefn(left *NodeList, defn *Node) {
 		if isblank(n) {
 			continue
 		}
-		if !(colasname(n) != 0) {
+		if !colasname(n) {
 			yyerrorl(int(defn.Lineno), "non-name %v on left side of :=", Nconv(n, 0))
 			nerr++
 			continue
@@ -735,7 +735,7 @@ func funcargs2(t *Type) {
 
 	if t.Thistuple != 0 {
 		for ft = getthisx(t).Type; ft != nil; ft = ft.Down {
-			if !(ft.Nname != nil) || !(ft.Nname.Sym != nil) {
+			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
 			n = ft.Nname // no need for newname(ft->nname->sym)
@@ -746,7 +746,7 @@ func funcargs2(t *Type) {
 
 	if t.Intuple != 0 {
 		for ft = getinargx(t).Type; ft != nil; ft = ft.Down {
-			if !(ft.Nname != nil) || !(ft.Nname.Sym != nil) {
+			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
 			n = ft.Nname
@@ -757,7 +757,7 @@ func funcargs2(t *Type) {
 
 	if t.Outtuple != 0 {
 		for ft = getoutargx(t).Type; ft != nil; ft = ft.Down {
-			if !(ft.Nname != nil) || !(ft.Nname.Sym != nil) {
+			if ft.Nname == nil || ft.Nname.Sym == nil {
 				continue
 			}
 			n = ft.Nname
@@ -925,7 +925,7 @@ func tostruct(l *NodeList) *Type {
 		tp = &f.Down
 	}
 
-	for f = t.Type; f != nil && !(t.Broke != 0); f = f.Down {
+	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -934,7 +934,7 @@ func tostruct(l *NodeList) *Type {
 	uniqgen++
 	checkdupfields(t.Type, "field")
 
-	if !(t.Broke != 0) {
+	if t.Broke == 0 {
 		checkwidth(t)
 	}
 
@@ -962,7 +962,7 @@ func tofunargs(l *NodeList) *Type {
 		tp = &f.Down
 	}
 
-	for f = t.Type; f != nil && !(t.Broke != 0); f = f.Down {
+	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -1072,7 +1072,7 @@ func tointerface(l *NodeList) *Type {
 		}
 	}
 
-	for f = t.Type; f != nil && !(t.Broke != 0); f = f.Down {
+	for f = t.Type; f != nil && t.Broke == 0; f = f.Down {
 		if f.Broke != 0 {
 			t.Broke = 1
 		}
@@ -1199,7 +1199,7 @@ func checkarglist(all *NodeList, input int) *NodeList {
 		}
 		n = Nod(ODCLFIELD, n, t)
 		if n.Right != nil && n.Right.Op == ODDD {
-			if !(input != 0) {
+			if input == 0 {
 				Yyerror("cannot use ... in output argument list")
 			} else if l.Next != nil {
 				Yyerror("can only use ... as final argument in list")
@@ -1232,23 +1232,23 @@ func fakethis() *Node {
  * *struct{} as the receiver.
  * (See fakethis above.)
  */
-func isifacemethod(f *Type) int {
+func isifacemethod(f *Type) bool {
 	var rcvr *Type
 	var t *Type
 
 	rcvr = getthisx(f).Type
 	if rcvr.Sym != nil {
-		return 0
+		return false
 	}
 	t = rcvr.Type
-	if !(Isptr[t.Etype] != 0) {
-		return 0
+	if Isptr[t.Etype] == 0 {
+		return false
 	}
 	t = t.Type
 	if t.Sym != nil || t.Etype != TSTRUCT || t.Type != nil {
-		return 0
+		return false
 	}
-	return 1
+	return true
 }
 
 /*
@@ -1480,7 +1480,7 @@ func addmethod(sf *Sym, t *Type, local bool, nointerface bool) {
 		}
 	}
 
-	if local && !(pa.Local != 0) {
+	if local && pa.Local == 0 {
 		// defining method on non-local type.
 		Yyerror("cannot define new methods on non-local type %v", Tconv(pa, 0))
 
@@ -1506,7 +1506,7 @@ func addmethod(sf *Sym, t *Type, local bool, nointerface bool) {
 	}
 
 	f = structfield(n)
-	f.Nointerface = uint8(bool2int(nointerface))
+	f.Nointerface = nointerface
 
 	// during import unexported method names should be in the type's package
 	if importpkg != nil && f.Sym != nil && !exportname(f.Sym.Name) && f.Sym.Pkg != structpkg {

src/cmd/internal/gc/esc.go

@@ -69,7 +69,7 @@ func escapes(all *NodeList) {
 
 func visit(n *Node) uint32 {
 	var min uint32
-	var recursive uint32
+	var recursive bool
 	var l *NodeList
 	var block *NodeList
 
@@ -95,7 +95,7 @@ func visit(n *Node) uint32 {
 		// If visitcodelist found its way back to n->walkgen, then this
 		// block is a set of mutually recursive functions.
 		// Otherwise it's just a lone function that does not recurse.
-		recursive = uint32(bool2int(min == n.Walkgen))
+		recursive = min == n.Walkgen
 
 		// Remove connected component from stack.
 		// Mark walkgen so that future visits return a large number
@@ -110,7 +110,7 @@ func visit(n *Node) uint32 {
 		l.Next = nil
 
 		// Run escape analysis on this set of functions.
-		analyze(block, int(recursive))
+		analyze(block, recursive)
 	}
 
 	return min
@@ -199,7 +199,7 @@ type EscState struct {
 	dstcount  int
 	edgecount int
 	noesc     *NodeList
-	recursive int
+	recursive bool
 }
 
 var tags [16]*Strlit
@@ -247,7 +247,7 @@ func parsetag(note *Strlit) int {
 	return EscReturn | em<<EscBits
 }
 
-func analyze(all *NodeList, recursive int) {
+func analyze(all *NodeList, recursive bool) {
 	var l *NodeList
 	var es EscState
 	var e *EscState
@@ -351,7 +351,7 @@ func escfunc(e *EscState, func_ *Node) {
 	}
 
 	// in a mutually recursive group we lose track of the return values
-	if e.recursive != 0 {
+	if e.recursive {
 		for ll = Curfn.Dcl; ll != nil; ll = ll.Next {
 			if ll.N.Op == ONAME && ll.N.Class == PPARAMOUT {
 				escflows(e, &e.theSink, ll.N)
@@ -387,7 +387,7 @@ func escloopdepth(e *EscState, n *Node) {
 
 	switch n.Op {
 	case OLABEL:
-		if !(n.Left != nil) || !(n.Left.Sym != nil) {
+		if n.Left == nil || n.Left.Sym == nil {
 			Fatal("esc:label without label: %v", Nconv(n, obj.FmtSign))
 		}
 
@@ -398,7 +398,7 @@ func escloopdepth(e *EscState, n *Node) {
 		n.Left.Sym.Label = &nonlooping
 
 	case OGOTO:
-		if !(n.Left != nil) || !(n.Left.Sym != nil) {
+		if n.Left == nil || n.Left.Sym == nil {
 			Fatal("esc:goto without label: %v", Nconv(n, obj.FmtSign))
 		}
 
@@ -509,7 +509,7 @@ func esc(e *EscState, n *Node, up *Node) {
 
 		// Everything but fixed array is a dereference.
 	case ORANGE:
-		if Isfixedarray(n.Type) != 0 && n.List != nil && n.List.Next != nil {
+		if Isfixedarray(n.Type) && n.List != nil && n.List.Next != nil {
 			escassign(e, n.List.Next.N, n.Right)
 		}
 
@@ -639,7 +639,7 @@ func esc(e *EscState, n *Node, up *Node) {
 		escassign(e, &e.theSink, n.Left)
 
 	case OAPPEND:
-		if !(n.Isddd != 0) {
+		if n.Isddd == 0 {
 			for ll = n.List.Next; ll != nil; ll = ll.Next {
 				escassign(e, &e.theSink, ll.N) // lose track of assign to dereference
 			}
@@ -651,7 +651,7 @@ func esc(e *EscState, n *Node, up *Node) {
 		escassign(e, n, n.Left)
 
 	case OARRAYLIT:
-		if Isslice(n.Type) != 0 {
+		if Isslice(n.Type) {
 			n.Esc = EscNone // until proven otherwise
 			e.noesc = list(e.noesc, n)
 			n.Escloopdepth = e.loopdepth
@@ -708,7 +708,7 @@ func esc(e *EscState, n *Node, up *Node) {
 				continue
 			}
 			a = v.Closure
-			if !(v.Byval != 0) {
+			if v.Byval == 0 {
 				a = Nod(OADDR, a, nil)
 				a.Lineno = v.Lineno
 				a.Escloopdepth = e.loopdepth
@@ -805,7 +805,6 @@ func escassign(e *EscState, dst *Node, src *Node) {
 	default:
 		Dump("dst", dst)
 		Fatal("escassign: unexpected dst")
-		fallthrough
 
 	case OARRAYLIT,
 		OCLOSURE,
@@ -829,7 +828,7 @@ func escassign(e *EscState, dst *Node, src *Node) {
 		return
 
 	case OINDEX:
-		if Isfixedarray(dst.Left.Type) != 0 {
+		if Isfixedarray(dst.Left.Type) {
 			escassign(e, dst.Left, src)
 			return
 		}
@@ -914,7 +913,7 @@ func escassign(e *EscState, dst *Node, src *Node) {
 
 		// Index of array preserves input value.
 	case OINDEX:
-		if Isfixedarray(src.Left.Type) != 0 {
+		if Isfixedarray(src.Left.Type) {
 			escassign(e, dst, src.Left)
 		}
 
@@ -999,7 +998,6 @@ func esccall(e *EscState, n *Node, up *Node) {
 	switch n.Op {
 	default:
 		Fatal("esccall")
-		fallthrough
 
 	case OCALLFUNC:
 		fn = n.Left
@@ -1044,7 +1042,7 @@ func esccall(e *EscState, n *Node, up *Node) {
 
 		for lr = fn.Ntype.List; ll != nil && lr != nil; (func() { ll = ll.Next; lr = lr.Next })() {
 			src = ll.N
-			if lr.N.Isddd != 0 && !(n.Isddd != 0) {
+			if lr.N.Isddd != 0 && n.Isddd == 0 {
 				// Introduce ODDDARG node to represent ... allocation.
 				src = Nod(ODDDARG, nil, nil)
 
@@ -1110,7 +1108,7 @@ func esccall(e *EscState, n *Node, up *Node) {
 
 	for t = getinargx(fntype).Type; ll != nil; ll = ll.Next {
 		src = ll.N
-		if t.Isddd != 0 && !(n.Isddd != 0) {
+		if t.Isddd != 0 && n.Isddd == 0 {
 			// Introduce ODDDARG node to represent ... allocation.
 			src = Nod(ODDDARG, nil, nil)
 
@@ -1243,7 +1241,7 @@ const (
 
 func escwalk(e *EscState, level int, dst *Node, src *Node) {
 	var ll *NodeList
-	var leaks int
+	var leaks bool
 	var newlevel int
 
 	if src.Walkgen == walkgen && src.Esclevel <= int32(level) {
@@ -1292,11 +1290,11 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 	// The second clause is for values pointed at by an object passed to a call
 	// that returns something reached via indirect from the object.
 	// We don't know which result it is or how many indirects, so we treat it as leaking.
-	leaks = bool2int(level <= 0 && dst.Escloopdepth < src.Escloopdepth || level < 0 && dst == &e.funcParam && haspointers(src.Type))
+	leaks = level <= 0 && dst.Escloopdepth < src.Escloopdepth || level < 0 && dst == &e.funcParam && haspointers(src.Type)
 
 	switch src.Op {
 	case ONAME:
-		if src.Class == PPARAM && (leaks != 0 || dst.Escloopdepth < 0) && src.Esc != EscHeap {
+		if src.Class == PPARAM && (leaks || dst.Escloopdepth < 0) && src.Esc != EscHeap {
 			src.Esc = EscScope
 			if Debug['m'] != 0 {
 				Warnl(int(src.Lineno), "leaking param: %v", Nconv(src, obj.FmtShort))
@@ -1306,7 +1304,7 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 		// Treat a PPARAMREF closure variable as equivalent to the
 		// original variable.
 		if src.Class == PPARAMREF {
-			if leaks != 0 && Debug['m'] != 0 {
+			if leaks && Debug['m'] != 0 {
 				Warnl(int(src.Lineno), "leaking closure reference %v", Nconv(src, obj.FmtShort))
 			}
 			escwalk(e, level, dst, src.Closure)
@@ -1314,7 +1312,7 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 
 	case OPTRLIT,
 		OADDR:
-		if leaks != 0 {
+		if leaks {
 			src.Esc = EscHeap
 			addrescapes(src.Left)
 			if Debug['m'] != 0 {
@@ -1329,7 +1327,7 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 		escwalk(e, newlevel, dst, src.Left)
 
 	case OARRAYLIT:
-		if Isfixedarray(src.Type) != 0 {
+		if Isfixedarray(src.Type) {
 			break
 		}
 		fallthrough
@@ -1349,7 +1347,7 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 		OCLOSURE,
 		OCALLPART,
 		ORUNESTR:
-		if leaks != 0 {
+		if leaks {
 			src.Esc = EscHeap
 			if Debug['m'] != 0 {
 				Warnl(int(src.Lineno), "%v escapes to heap", Nconv(src, obj.FmtShort))
@@ -1365,7 +1363,7 @@ func escwalk(e *EscState, level int, dst *Node, src *Node) {
 		escwalk(e, level, dst, src.Left)
 
 	case OINDEX:
-		if Isfixedarray(src.Left.Type) != 0 {
+		if Isfixedarray(src.Left.Type) {
 			escwalk(e, level, dst, src.Left)
 			break
 		}

src/cmd/internal/gc/export.go

@@ -42,19 +42,19 @@ func exportname(s string) bool {
 	return unicode.IsUpper(r)
 }
 
-func initname(s string) int {
-	return bool2int(s == "init")
+func initname(s string) bool {
+	return s == "init"
 }
 
 // exportedsym reports whether a symbol will be visible
 // to files that import our package.
-func exportedsym(sym *Sym) int {
+func exportedsym(sym *Sym) bool {
 	// Builtins are visible everywhere.
 	if sym.Pkg == builtinpkg || sym.Origpkg == builtinpkg {
-		return 1
+		return true
 	}
 
-	return bool2int(sym.Pkg == localpkg && exportname(sym.Name))
+	return sym.Pkg == localpkg && exportname(sym.Name)
 }
 
 func autoexport(n *Node, ctxt int) {
@@ -69,10 +69,10 @@ func autoexport(n *Node, ctxt int) {
 	}
 
 	// -A is for cmd/gc/mkbuiltin script, so export everything
-	if Debug['A'] != 0 || exportname(n.Sym.Name) || initname(n.Sym.Name) != 0 {
+	if Debug['A'] != 0 || exportname(n.Sym.Name) || initname(n.Sym.Name) {
 		exportsym(n)
 	}
-	if asmhdr != "" && n.Sym.Pkg == localpkg && !(n.Sym.Flags&SymAsm != 0) {
+	if asmhdr != "" && n.Sym.Pkg == localpkg && n.Sym.Flags&SymAsm == 0 {
 		n.Sym.Flags |= SymAsm
 		asmlist = list(asmlist, n)
 	}
@@ -86,7 +86,7 @@ func dumppkg(p *Pkg) {
 	}
 	p.Exported = 1
 	suffix = ""
-	if !(p.Direct != 0) {
+	if p.Direct == 0 {
 		suffix = " // indirect"
 	}
 	fmt.Fprintf(bout, "\timport %s \"%v\"%s\n", p.Name, Zconv(p.Path, 0), suffix)
@@ -102,7 +102,7 @@ func reexportdeplist(ll *NodeList) {
 func reexportdep(n *Node) {
 	var t *Type
 
-	if !(n != nil) {
+	if n == nil {
 		return
 	}
 
@@ -118,14 +118,14 @@ func reexportdep(n *Node) {
 			}
 
 			// nodes for method calls.
-			if !(n.Type != nil) || n.Type.Thistuple > 0 {
+			if n.Type == nil || n.Type.Thistuple > 0 {
 				break
 			}
 			fallthrough
 
 			// fallthrough
 		case PEXTERN:
-			if n.Sym != nil && !(exportedsym(n.Sym) != 0) {
+			if n.Sym != nil && !exportedsym(n.Sym) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport name %v\n", Sconv(n.Sym, 0))
 				}
@@ -141,7 +141,7 @@ func reexportdep(n *Node) {
 			if Isptr[t.Etype] != 0 {
 				t = t.Type
 			}
-			if t != nil && t.Sym != nil && t.Sym.Def != nil && !(exportedsym(t.Sym) != 0) {
+			if t != nil && t.Sym != nil && t.Sym.Def != nil && !exportedsym(t.Sym) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport type %v from declaration\n", Sconv(t.Sym, 0))
 				}
@@ -155,7 +155,7 @@ func reexportdep(n *Node) {
 			if Isptr[t.Etype] != 0 {
 				t = t.Type
 			}
-			if t != nil && t.Sym != nil && t.Sym.Def != nil && !(exportedsym(t.Sym) != 0) {
+			if t != nil && t.Sym != nil && t.Sym.Def != nil && !exportedsym(t.Sym) {
 				if Debug['E'] != 0 {
 					fmt.Printf("reexport literal type %v\n", Sconv(t.Sym, 0))
 				}
@@ -166,7 +166,7 @@ func reexportdep(n *Node) {
 
 		// fallthrough
 	case OTYPE:
-		if n.Sym != nil && !(exportedsym(n.Sym) != 0) {
+		if n.Sym != nil && !exportedsym(n.Sym) {
 			if Debug['E'] != 0 {
 				fmt.Printf("reexport literal/type %v\n", Sconv(n.Sym, 0))
 			}
@@ -192,10 +192,10 @@ func reexportdep(n *Node) {
 		OMAKECHAN:
 		t = n.Type
 
-		if !(t.Sym != nil) && t.Type != nil {
+		if t.Sym == nil && t.Type != nil {
 			t = t.Type
 		}
-		if t != nil && t.Sym != nil && t.Sym.Def != nil && !(exportedsym(t.Sym) != 0) {
+		if t != nil && t.Sym != nil && t.Sym.Def != nil && !exportedsym(t.Sym) {
 			if Debug['E'] != 0 {
 				fmt.Printf("reexport type for expression %v\n", Sconv(t.Sym, 0))
 			}
@@ -227,7 +227,7 @@ func dumpexportconst(s *Sym) {
 	t = n.Type // may or may not be specified
 	dumpexporttype(t)
 
-	if t != nil && !(isideal(t) != 0) {
+	if t != nil && !isideal(t) {
 		fmt.Fprintf(bout, "\tconst %v %v = %v\n", Sconv(s, obj.FmtSharp), Tconv(t, obj.FmtSharp), Vconv(&n.Val, obj.FmtSharp))
 	} else {
 		fmt.Fprintf(bout, "\tconst %v = %v\n", Sconv(s, obj.FmtSharp), Vconv(&n.Val, obj.FmtSharp))
@@ -329,7 +329,7 @@ func dumpexporttype(t *Type) {
 	fmt.Fprintf(bout, "\ttype %v %v\n", Sconv(t.Sym, obj.FmtSharp), Tconv(t, obj.FmtSharp|obj.FmtLong))
 	for i = 0; i < n; i++ {
 		f = m[i]
-		if f.Nointerface != 0 {
+		if f.Nointerface {
 			fmt.Fprintf(bout, "\t//go:nointerface\n")
 		}
 		if f.Type.Nname != nil && f.Type.Nname.Inl != nil { // nname was set by caninl
@@ -428,7 +428,7 @@ func importsym(s *Sym, op int) *Sym {
 
 	// mark the symbol so it is not reexported
 	if s.Def == nil {
-		if exportname(s.Name) || initname(s.Name) != 0 {
+		if exportname(s.Name) || initname(s.Name) {
 			s.Flags |= SymExport
 		} else {
 			s.Flags |= SymPackage // package scope
@@ -474,7 +474,7 @@ func importimport(s *Sym, z *Strlit) {
 		Yyerror("conflicting names %s and %s for package \"%v\"", p.Name, s.Name, Zconv(p.Path, 0))
 	}
 
-	if !(incannedimport != 0) && myimportpath != "" && z.S == myimportpath {
+	if incannedimport == 0 && myimportpath != "" && z.S == myimportpath {
 		Yyerror("import \"%v\": package depends on \"%v\" (import cycle)", Zconv(importpkg.Path, 0), Zconv(z, 0))
 		errorexit()
 	}

src/cmd/internal/gc/fmt.go

@@ -207,15 +207,15 @@ func Jconv(n *Node, flag int) string {
 
 	c = flag & obj.FmtShort
 
-	if !(c != 0) && n.Ullman != 0 {
+	if c == 0 && n.Ullman != 0 {
 		fp += fmt.Sprintf(" u(%d)", n.Ullman)
 	}
 
-	if !(c != 0) && n.Addable != 0 {
+	if c == 0 && n.Addable != 0 {
 		fp += fmt.Sprintf(" a(%d)", n.Addable)
 	}
 
-	if !(c != 0) && n.Vargen != 0 {
+	if c == 0 && n.Vargen != 0 {
 		fp += fmt.Sprintf(" g(%d)", n.Vargen)
 	}
 
@@ -223,7 +223,7 @@ func Jconv(n *Node, flag int) string {
 		fp += fmt.Sprintf(" l(%d)", n.Lineno)
 	}
 
-	if !(c != 0) && n.Xoffset != BADWIDTH {
+	if c == 0 && n.Xoffset != BADWIDTH {
 		fp += fmt.Sprintf(" x(%d%+d)", n.Xoffset, n.Stkdelta)
 	}
 
@@ -261,7 +261,7 @@ func Jconv(n *Node, flag int) string {
 		fp += fmt.Sprintf(" esc(no)")
 
 	case EscNever:
-		if !(c != 0) {
+		if c == 0 {
 			fp += fmt.Sprintf(" esc(N)")
 		}
 
@@ -273,11 +273,11 @@ func Jconv(n *Node, flag int) string {
 		fp += fmt.Sprintf(" ld(%d)", n.Escloopdepth)
 	}
 
-	if !(c != 0) && n.Typecheck != 0 {
+	if c == 0 && n.Typecheck != 0 {
 		fp += fmt.Sprintf(" tc(%d)", n.Typecheck)
 	}
 
-	if !(c != 0) && n.Dodata != 0 {
+	if c == 0 && n.Dodata != 0 {
 		fp += fmt.Sprintf(" dd(%d)", n.Dodata)
 	}
 
@@ -301,7 +301,7 @@ func Jconv(n *Node, flag int) string {
 		fp += fmt.Sprintf(" assigned")
 	}
 
-	if !(c != 0) && n.Used != 0 {
+	if c == 0 && n.Used != 0 {
 		fp += fmt.Sprintf(" used(%d)", n.Used)
 	}
 	return fp
@@ -497,7 +497,7 @@ func symfmt(s *Sym, flag int) string {
 
 	var p string
 
-	if s.Pkg != nil && !(flag&obj.FmtShort != 0 /*untyped*/) {
+	if s.Pkg != nil && flag&obj.FmtShort == 0 /*untyped*/ {
 		switch fmtmode {
 		case FErr: // This is for the user
 			if s.Pkg == localpkg {
@@ -608,7 +608,7 @@ func typefmt(t *Type, flag int) string {
 	}
 
 	// Unless the 'l' flag was specified, if the type has a name, just print that name.
-	if !(flag&obj.FmtLong != 0 /*untyped*/) && t.Sym != nil && t.Etype != TFIELD && t != Types[t.Etype] {
+	if flag&obj.FmtLong == 0 /*untyped*/ && t.Sym != nil && t.Etype != TFIELD && t != Types[t.Etype] {
 		switch fmtmode {
 		case FTypeId:
 			if flag&obj.FmtShort != 0 /*untyped*/ {
@@ -802,7 +802,7 @@ func typefmt(t *Type, flag int) string {
 		return fp
 
 	case TFIELD:
-		if !(flag&obj.FmtShort != 0 /*untyped*/) {
+		if flag&obj.FmtShort == 0 /*untyped*/ {
 			s = t.Sym
 
 			// Take the name from the original, lest we substituted it with ~r%d or ~b%d.
@@ -822,7 +822,7 @@ func typefmt(t *Type, flag int) string {
 				}
 			}
 
-			if s != nil && !(t.Embedded != 0) {
+			if s != nil && t.Embedded == 0 {
 				if t.Funarg != 0 {
 					fp += fmt.Sprintf("%v ", Nconv(t.Nname, 0))
 				} else if flag&obj.FmtLong != 0 /*untyped*/ {
@@ -850,7 +850,7 @@ func typefmt(t *Type, flag int) string {
 			fp += fmt.Sprintf("%v", Tconv(t.Type, 0))
 		}
 
-		if !(flag&obj.FmtShort != 0 /*untyped*/) && t.Note != nil {
+		if flag&obj.FmtShort == 0 /*untyped*/ && t.Note != nil {
 			fp += fmt.Sprintf(" \"%v\"", Zconv(t.Note, 0))
 		}
 		return fp
@@ -882,23 +882,23 @@ func typefmt(t *Type, flag int) string {
 }
 
 // Statements which may be rendered with a simplestmt as init.
-func stmtwithinit(op int) int {
+func stmtwithinit(op int) bool {
 	switch op {
 	case OIF,
 		OFOR,
 		OSWITCH:
-		return 1
+		return true
 	}
 
-	return 0
+	return false
 }
 
 func stmtfmt(n *Node) string {
 	var f string
 
-	var complexinit int
-	var simpleinit int
-	var extrablock int
+	var complexinit bool
+	var simpleinit bool
+	var extrablock bool
 
 	// some statements allow for an init, but at most one,
 	// but we may have an arbitrary number added, eg by typecheck
@@ -906,19 +906,19 @@ func stmtfmt(n *Node) string {
 	// block starting with the init statements.
 
 	// if we can just say "for" n->ninit; ... then do so
-	simpleinit = bool2int(n.Ninit != nil && !(n.Ninit.Next != nil) && !(n.Ninit.N.Ninit != nil) && stmtwithinit(int(n.Op)) != 0)
+	simpleinit = n.Ninit != nil && n.Ninit.Next == nil && n.Ninit.N.Ninit == nil && stmtwithinit(int(n.Op))
 
 	// otherwise, print the inits as separate statements
-	complexinit = bool2int(n.Ninit != nil && !(simpleinit != 0) && (fmtmode != FErr))
+	complexinit = n.Ninit != nil && !simpleinit && (fmtmode != FErr)
 
 	// but if it was for if/for/switch, put in an extra surrounding block to limit the scope
-	extrablock = bool2int(complexinit != 0 && stmtwithinit(int(n.Op)) != 0)
+	extrablock = complexinit && stmtwithinit(int(n.Op))
 
-	if extrablock != 0 {
+	if extrablock {
 		f += "{"
 	}
 
-	if complexinit != 0 {
+	if complexinit {
 		f += fmt.Sprintf(" %v; ", Hconv(n.Ninit, 0))
 	}
 
@@ -951,7 +951,7 @@ func stmtfmt(n *Node) string {
 			break
 		}
 
-		if n.Colas != 0 && !(complexinit != 0) {
+		if n.Colas != 0 && !complexinit {
 			f += fmt.Sprintf("%v := %v", Nconv(n.Left, 0), Nconv(n.Right, 0))
 		} else {
 			f += fmt.Sprintf("%v = %v", Nconv(n.Left, 0), Nconv(n.Right, 0))
@@ -970,7 +970,7 @@ func stmtfmt(n *Node) string {
 		f += fmt.Sprintf("%v %v= %v", Nconv(n.Left, 0), Oconv(int(n.Etype), obj.FmtSharp), Nconv(n.Right, 0))
 
 	case OAS2:
-		if n.Colas != 0 && !(complexinit != 0) {
+		if n.Colas != 0 && !complexinit {
 			f += fmt.Sprintf("%v := %v", Hconv(n.List, obj.FmtComma), Hconv(n.Rlist, obj.FmtComma))
 			break
 		}
@@ -996,7 +996,7 @@ func stmtfmt(n *Node) string {
 		f += fmt.Sprintf("defer %v", Nconv(n.Left, 0))
 
 	case OIF:
-		if simpleinit != 0 {
+		if simpleinit {
 			f += fmt.Sprintf("if %v; %v { %v }", Nconv(n.Ninit.N, 0), Nconv(n.Ntest, 0), Hconv(n.Nbody, 0))
 		} else {
 			f += fmt.Sprintf("if %v { %v }", Nconv(n.Ntest, 0), Hconv(n.Nbody, 0))
@@ -1012,7 +1012,7 @@ func stmtfmt(n *Node) string {
 		}
 
 		f += "for"
-		if simpleinit != 0 {
+		if simpleinit {
 			f += fmt.Sprintf(" %v;", Nconv(n.Ninit.N, 0))
 		} else if n.Nincr != nil {
 			f += " ;"
@@ -1024,7 +1024,7 @@ func stmtfmt(n *Node) string {
 
 		if n.Nincr != nil {
 			f += fmt.Sprintf("; %v", Nconv(n.Nincr, 0))
-		} else if simpleinit != 0 {
+		} else if simpleinit {
 			f += ";"
 		}
 
@@ -1051,7 +1051,7 @@ func stmtfmt(n *Node) string {
 		}
 
 		f += fmt.Sprintf("%v", Oconv(int(n.Op), obj.FmtSharp))
-		if simpleinit != 0 {
+		if simpleinit {
 			f += fmt.Sprintf(" %v;", Nconv(n.Ninit.N, 0))
 		}
 		if n.Ntest != nil {
@@ -1087,7 +1087,7 @@ func stmtfmt(n *Node) string {
 	}
 
 ret:
-	if extrablock != 0 {
+	if extrablock {
 		f += "}"
 	}
 
@@ -1211,7 +1211,7 @@ func exprfmt(n *Node, prec int) string {
 	var f string
 
 	var nprec int
-	var ptrlit int
+	var ptrlit bool
 	var l *NodeList
 
 	for n != nil && n.Implicit != 0 && (n.Op == OIND || n.Op == OADDR) {
@@ -1368,10 +1368,10 @@ func exprfmt(n *Node, prec int) string {
 		return f
 
 	case OCOMPLIT:
-		ptrlit = bool2int(n.Right != nil && n.Right.Implicit != 0 && n.Right.Type != nil && Isptr[n.Right.Type.Etype] != 0)
+		ptrlit = n.Right != nil && n.Right.Implicit != 0 && n.Right.Type != nil && Isptr[n.Right.Type.Etype] != 0
 		if fmtmode == FErr {
-			if n.Right != nil && n.Right.Type != nil && !(n.Implicit != 0) {
-				if ptrlit != 0 {
+			if n.Right != nil && n.Right.Type != nil && n.Implicit == 0 {
+				if ptrlit {
 					f += fmt.Sprintf("&%v literal", Tconv(n.Right.Type.Type, 0))
 					return f
 				} else {
@@ -1384,7 +1384,7 @@ func exprfmt(n *Node, prec int) string {
 			return f
 		}
 
-		if fmtmode == FExp && ptrlit != 0 {
+		if fmtmode == FExp && ptrlit {
 			// typecheck has overwritten OIND by OTYPE with pointer type.
 			f += fmt.Sprintf("(&%v{ %v })", Tconv(n.Right.Type.Type, 0), Hconv(n.List, obj.FmtComma))
 			return f
@@ -1418,7 +1418,7 @@ func exprfmt(n *Node, prec int) string {
 				}
 			}
 
-			if !(n.Implicit != 0) {
+			if n.Implicit == 0 {
 				f += "})"
 				return f
 			}
@@ -1454,11 +1454,11 @@ func exprfmt(n *Node, prec int) string {
 			}
 		}
 
-		if !(n.Left != nil) && n.Right != nil {
+		if n.Left == nil && n.Right != nil {
 			f += fmt.Sprintf(":%v", Nconv(n.Right, 0))
 			return f
 		}
-		if n.Left != nil && !(n.Right != nil) {
+		if n.Left != nil && n.Right == nil {
 			f += fmt.Sprintf("%v:", Nconv(n.Left, 0))
 			return f
 		}
@@ -1686,15 +1686,15 @@ func indent(s string) string {
 func nodedump(n *Node, flag int) string {
 	var fp string
 
-	var recur int
+	var recur bool
 
 	if n == nil {
 		return fp
 	}
 
-	recur = bool2int(!(flag&obj.FmtShort != 0 /*untyped*/))
+	recur = flag&obj.FmtShort == 0 /*untyped*/
 
-	if recur != 0 {
+	if recur {
 		fp = indent(fp)
 		if dumpdepth > 10 {
 			fp += "..."
@@ -1727,7 +1727,7 @@ func nodedump(n *Node, flag int) string {
 		} else {
 			fp += fmt.Sprintf("%v%v", Oconv(int(n.Op), 0), Jconv(n, 0))
 		}
-		if recur != 0 && n.Type == nil && n.Ntype != nil {
+		if recur && n.Type == nil && n.Ntype != nil {
 			fp = indent(fp)
 			fp += fmt.Sprintf("%v-ntype%v", Oconv(int(n.Op), 0), Nconv(n.Ntype, 0))
 		}
@@ -1737,7 +1737,7 @@ func nodedump(n *Node, flag int) string {
 
 	case OTYPE:
 		fp += fmt.Sprintf("%v %v%v type=%v", Oconv(int(n.Op), 0), Sconv(n.Sym, 0), Jconv(n, 0), Tconv(n.Type, 0))
-		if recur != 0 && n.Type == nil && n.Ntype != nil {
+		if recur && n.Type == nil && n.Ntype != nil {
 			fp = indent(fp)
 			fp += fmt.Sprintf("%v-ntype%v", Oconv(int(n.Op), 0), Nconv(n.Ntype, 0))
 		}
@@ -1751,7 +1751,7 @@ func nodedump(n *Node, flag int) string {
 		fp += fmt.Sprintf(" %v", Tconv(n.Type, 0))
 	}
 
-	if recur != 0 {
+	if recur {
 		if n.Left != nil {
 			fp += fmt.Sprintf("%v", Nconv(n.Left, 0))
 		}

src/cmd/internal/gc/gen.go

@@ -109,7 +109,7 @@ func addrescapes(n *Node) {
 	// is always a heap pointer anyway.
 	case ODOT,
 		OINDEX:
-		if !(Isslice(n.Left.Type) != 0) {
+		if !Isslice(n.Left.Type) {
 			addrescapes(n.Left)
 		}
 	}
@@ -253,7 +253,6 @@ func cgen_proc(n *Node, proc int) {
 	switch n.Left.Op {
 	default:
 		Fatal("cgen_proc: unknown call %v", Oconv(int(n.Left.Op), 0))
-		fallthrough
 
 	case OCALLMETH:
 		Cgen_callmeth(n.Left, proc)
@@ -280,7 +279,7 @@ func cgen_dcl(n *Node) {
 		Fatal("cgen_dcl")
 	}
 
-	if !(n.Class&PHEAP != 0) {
+	if n.Class&PHEAP == 0 {
 		return
 	}
 	if compiling_runtime != 0 {
@@ -304,7 +303,7 @@ func cgen_discard(nr *Node) {
 
 	switch nr.Op {
 	case ONAME:
-		if !(nr.Class&PHEAP != 0) && nr.Class != PEXTERN && nr.Class != PFUNC && nr.Class != PPARAMREF {
+		if nr.Class&PHEAP == 0 && nr.Class != PEXTERN && nr.Class != PFUNC && nr.Class != PPARAMREF {
 			gused(nr)
 		}
 
@@ -480,7 +479,7 @@ func Cgen_slice(n *Node, res *Node) {
 		tmpcap = tmplen
 	}
 
-	if isnil(n.Left) != 0 {
+	if isnil(n.Left) {
 		Tempname(&src, n.Left.Type)
 		Thearch.Cgen(n.Left, &src)
 	} else {
@@ -491,7 +490,7 @@ func Cgen_slice(n *Node, res *Node) {
 	}
 
 	if n.Op == OSLICEARR || n.Op == OSLICE3ARR {
-		if !(Isptr[n.Left.Type.Etype] != 0) {
+		if Isptr[n.Left.Type.Etype] == 0 {
 			Fatal("slicearr is supposed to work on pointer: %v\n", Nconv(n, obj.FmtSign))
 		}
 		Thearch.Cgen(&src, base)
@@ -668,13 +667,12 @@ func gen(n *Node) {
 	var p2 *obj.Prog
 	var p3 *obj.Prog
 	var lab *Label
-	var wasregalloc int32
 
 	//dump("gen", n);
 
 	lno = setlineno(n)
 
-	wasregalloc = int32(Thearch.Anyregalloc())
+	wasregalloc := Thearch.Anyregalloc()
 
 	if n == nil {
 		goto ret
@@ -879,7 +877,7 @@ func gen(n *Node) {
 		cgen_dcl(n.Left)
 
 	case OAS:
-		if gen_as_init(n) != 0 {
+		if gen_as_init(n) {
 			break
 		}
 		Cgen_as(n.Left, n.Right)
@@ -911,7 +909,7 @@ func gen(n *Node) {
 	}
 
 ret:
-	if int32(Thearch.Anyregalloc()) != wasregalloc {
+	if Thearch.Anyregalloc() != wasregalloc {
 		Dump("node", n)
 		Fatal("registers left allocated")
 	}
@@ -936,7 +934,7 @@ func Cgen_as(nl *Node, nr *Node) {
 		return
 	}
 
-	if nr == nil || iszero(nr) != 0 {
+	if nr == nil || iszero(nr) {
 		// heaps should already be clear
 		if nr == nil && (nl.Class&PHEAP != 0) {
 			return
@@ -946,7 +944,7 @@ func Cgen_as(nl *Node, nr *Node) {
 		if tl == nil {
 			return
 		}
-		if Isfat(tl) != 0 {
+		if Isfat(tl) {
 			if nl.Op == ONAME {
 				Gvardef(nl)
 			}
@@ -1002,7 +1000,7 @@ func checklabels() {
 			continue
 		}
 
-		if lab.Use == nil && !(lab.Used != 0) {
+		if lab.Use == nil && lab.Used == 0 {
 			yyerrorl(int(lab.Def.Lineno), "label %v defined and not used", Sconv(lab.Sym, 0))
 			continue
 		}

src/cmd/internal/gc/go.go

@@ -7,7 +7,6 @@ package gc
 import (
 	"bytes"
 	"cmd/internal/obj"
-	"encoding/binary"
 )
 
 // Copyright 2009 The Go Authors. All rights reserved.
@@ -162,7 +161,7 @@ type Node struct {
 	Addable        uint8
 	Trecur         uint8
 	Etype          uint8
-	Bounded        uint8
+	Bounded        bool
 	Class          uint8
 	Method         uint8
 	Embedded       uint8
@@ -191,7 +190,7 @@ type Node struct {
 	Likely         int8
 	Hasbreak       uint8
 	Needzero       uint8
-	Needctxt       uint8
+	Needctxt       bool
 	Esc            uint
 	Funcdepth      int
 	Type           *Type
@@ -245,7 +244,7 @@ type NodeList struct {
 
 type Type struct {
 	Etype       uint8
-	Nointerface uint8
+	Nointerface bool
 	Noalg       uint8
 	Chan        uint8
 	Trecur      uint8
@@ -918,6 +917,10 @@ var nblank *Node
 
 var Use_sse int
 
+var hunk string
+
+var nhunk int32
+
 var thunk int32
 
 var Funcdepth int
@@ -1119,7 +1122,6 @@ const (
 )
 
 type Arch struct {
-	ByteOrder      binary.ByteOrder
 	Thechar        int
 	Thestring      string
 	Thelinkarch    *obj.LinkArch
@@ -1127,7 +1129,7 @@ type Arch struct {
 	REGSP          int
 	REGCTXT        int
 	MAXWIDTH       int64
-	Anyregalloc    func() int
+	Anyregalloc    func() bool
 	Betypeinit     func()
 	Bgen           func(*Node, bool, int, *obj.Prog)
 	Cgen           func(*Node, *Node)
@@ -1148,10 +1150,10 @@ type Arch struct {
 	Proginfo       func(*ProgInfo, *obj.Prog)
 	Regalloc       func(*Node, *Type, *Node)
 	Regfree        func(*Node)
-	Regtyp         func(*obj.Addr) int
-	Sameaddr       func(*obj.Addr, *obj.Addr) int
-	Smallindir     func(*obj.Addr, *obj.Addr) int
-	Stackaddr      func(*obj.Addr) int
+	Regtyp         func(*obj.Addr) bool
+	Sameaddr       func(*obj.Addr, *obj.Addr) bool
+	Smallindir     func(*obj.Addr, *obj.Addr) bool
+	Stackaddr      func(*obj.Addr) bool
 	Excludedregs   func() uint64
 	RtoB           func(int) uint64
 	FtoB           func(int) uint64

src/cmd/internal/gc/gsubr.go

@@ -41,7 +41,7 @@ var dpc *obj.Prog
 /*
  * Is this node a memory operand?
  */
-func Ismem(n *Node) int {
+func Ismem(n *Node) bool {
 	switch n.Op {
 	case OITAB,
 		OSPTR,
@@ -51,29 +51,29 @@ func Ismem(n *Node) int {
 		ONAME,
 		OPARAM,
 		OCLOSUREVAR:
-		return 1
+		return true
 
 	case OADDR:
-		return bool2int(Thearch.Thechar == '6' || Thearch.Thechar == '9') // because 6g uses PC-relative addressing; TODO(rsc): not sure why 9g too
+		return Thearch.Thechar == '6' || Thearch.Thechar == '9' // because 6g uses PC-relative addressing; TODO(rsc): not sure why 9g too
 	}
 
-	return 0
+	return false
 }
 
-func Samereg(a *Node, b *Node) int {
+func Samereg(a *Node, b *Node) bool {
 	if a == nil || b == nil {
-		return 0
+		return false
 	}
 	if a.Op != OREGISTER {
-		return 0
+		return false
 	}
 	if b.Op != OREGISTER {
-		return 0
+		return false
 	}
 	if a.Val.U.Reg != b.Val.U.Reg {
-		return 0
+		return false
 	}
-	return 1
+	return true
 }
 
 /*
@@ -174,15 +174,15 @@ func fixautoused(p *obj.Prog) {
 
 	for lp = &p; ; {
 		p = *lp
-		if !(p != nil) {
+		if p == nil {
 			break
 		}
-		if p.As == obj.ATYPE && p.From.Node != nil && p.From.Name == obj.NAME_AUTO && !(((p.From.Node).(*Node)).Used != 0) {
+		if p.As == obj.ATYPE && p.From.Node != nil && p.From.Name == obj.NAME_AUTO && ((p.From.Node).(*Node)).Used == 0 {
 			*lp = p.Link
 			continue
 		}
 
-		if (p.As == obj.AVARDEF || p.As == obj.AVARKILL) && p.To.Node != nil && !(((p.To.Node).(*Node)).Used != 0) {
+		if (p.As == obj.AVARDEF || p.As == obj.AVARKILL) && p.To.Node != nil && ((p.To.Node).(*Node)).Used == 0 {
 			// Cannot remove VARDEF instruction, because - unlike TYPE handled above -
 			// VARDEFs are interspersed with other code, and a jump might be using the
 			// VARDEF as a target. Replace with a no-op instead. A later pass will remove
@@ -256,18 +256,18 @@ func gused(n *Node) {
 	Thearch.Gins(obj.ANOP, n, nil) // used
 }
 
-func Isfat(t *Type) int {
+func Isfat(t *Type) bool {
 	if t != nil {
 		switch t.Etype {
 		case TSTRUCT,
 			TARRAY,
 			TSTRING,
 			TINTER: // maybe remove later
-			return 1
+			return true
 		}
 	}
 
-	return 0
+	return false
 }
 
 func markautoused(p *obj.Prog) {
@@ -289,7 +289,7 @@ func markautoused(p *obj.Prog) {
 func Naddr(n *Node, a *obj.Addr, canemitcode int) {
 	var s *Sym
 
-	*a = obj.Zprog.From
+	*a = obj.Addr{}
 	if n == nil {
 		return
 	}
@@ -343,7 +343,7 @@ func Naddr(n *Node, a *obj.Addr, canemitcode int) {
 		a.Node = n.Left.Orig
 
 	case OCLOSUREVAR:
-		if !(Curfn.Needctxt != 0) {
+		if !Curfn.Needctxt {
 			Fatal("closurevar without needctxt")
 		}
 		a.Type = obj.TYPE_MEM
@@ -383,7 +383,6 @@ func Naddr(n *Node, a *obj.Addr, canemitcode int) {
 		switch n.Class {
 		default:
 			Fatal("naddr: ONAME class %v %d\n", Sconv(n.Sym, 0), n.Class)
-			fallthrough
 
 		case PEXTERN:
 			a.Name = obj.NAME_EXTERN

src/cmd/internal/gc/init.go

@@ -53,7 +53,7 @@ func renameinit() *Sym {
  *		return					(11)
  *	}
  */
-func anyinit(n *NodeList) int {
+func anyinit(n *NodeList) bool {
 	var h uint32
 	var s *Sym
 	var l *NodeList
@@ -68,20 +68,20 @@ func anyinit(n *NodeList) int {
 			break
 
 		case OAS:
-			if isblank(l.N.Left) && candiscard(l.N.Right) != 0 {
+			if isblank(l.N.Left) && candiscard(l.N.Right) {
 				break
 			}
 			fallthrough
 
 			// fall through
 		default:
-			return 1
+			return true
 		}
 	}
 
 	// is this main
 	if localpkg.Name == "main" {
-		return 1
+		return true
 	}
 
 	// is there an explicit init function
@@ -89,7 +89,7 @@ func anyinit(n *NodeList) int {
 
 	s = Lookup(namebuf)
 	if s.Def != nil {
-		return 1
+		return true
 	}
 
 	// are there any imported init functions
@@ -101,12 +101,12 @@ func anyinit(n *NodeList) int {
 			if s.Def == nil {
 				continue
 			}
-			return 1
+			return true
 		}
 	}
 
 	// then none
-	return 0
+	return false
 }
 
 func fninit(n *NodeList) {
@@ -126,7 +126,7 @@ func fninit(n *NodeList) {
 	}
 
 	n = initfix(n)
-	if !(anyinit(n) != 0) {
+	if !anyinit(n) {
 		return
 	}
 

src/cmd/internal/gc/inl.go

@@ -56,7 +56,7 @@ func fnpkg(fn *Node) *Pkg {
 		if Isptr[rcvr.Etype] != 0 {
 			rcvr = rcvr.Type
 		}
-		if !(rcvr.Sym != nil) {
+		if rcvr.Sym == nil {
 			Fatal("receiver with no sym: [%v] %v  (%v)", Sconv(fn.Sym, 0), Nconv(fn, obj.FmtLong), Tconv(rcvr, 0))
 		}
 		return rcvr.Sym.Pkg
@@ -114,7 +114,7 @@ func caninl(fn *Node) {
 	if fn.Op != ODCLFUNC {
 		Fatal("caninl %v", Nconv(fn, 0))
 	}
-	if !(fn.Nname != nil) {
+	if fn.Nname == nil {
 		Fatal("caninl no nname %v", Nconv(fn, obj.FmtSign))
 	}
 
@@ -137,7 +137,7 @@ func caninl(fn *Node) {
 	}
 
 	budget = 40 // allowed hairyness
-	if ishairylist(fn.Nbody, &budget) != 0 {
+	if ishairylist(fn.Nbody, &budget) {
 		return
 	}
 
@@ -162,18 +162,18 @@ func caninl(fn *Node) {
 }
 
 // Look for anything we want to punt on.
-func ishairylist(ll *NodeList, budget *int) int {
+func ishairylist(ll *NodeList, budget *int) bool {
 	for ; ll != nil; ll = ll.Next {
-		if ishairy(ll.N, budget) != 0 {
-			return 1
+		if ishairy(ll.N, budget) {
+			return true
 		}
 	}
-	return 0
+	return false
 }
 
-func ishairy(n *Node, budget *int) int {
-	if !(n != nil) {
-		return 0
+func ishairy(n *Node, budget *int) bool {
+	if n == nil {
+		return false
 	}
 
 	// Things that are too hairy, irrespective of the budget
@@ -185,7 +185,7 @@ func ishairy(n *Node, budget *int) int {
 		OPANIC,
 		ORECOVER:
 		if Debug['l'] < 4 {
-			return 1
+			return true
 		}
 
 	case OCLOSURE,
@@ -199,12 +199,12 @@ func ishairy(n *Node, budget *int) int {
 		ODCLTYPE,  // can't print yet
 		ODCLCONST, // can't print yet
 		ORETJMP:
-		return 1
+		return true
 	}
 
 	(*budget)--
 
-	return bool2int(*budget < 0 || ishairy(n.Left, budget) != 0 || ishairy(n.Right, budget) != 0 || ishairylist(n.List, budget) != 0 || ishairylist(n.Rlist, budget) != 0 || ishairylist(n.Ninit, budget) != 0 || ishairy(n.Ntest, budget) != 0 || ishairy(n.Nincr, budget) != 0 || ishairylist(n.Nbody, budget) != 0 || ishairylist(n.Nelse, budget) != 0)
+	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) || ishairy(n.Nincr, budget) || ishairylist(n.Nbody, budget) || ishairylist(n.Nelse, budget)
 }
 
 // Inlcopy and inlcopylist recursively copy the body of a function.
@@ -506,7 +506,7 @@ func mkinlcall(np **Node, fn *Node, isddd int) {
 
 func tinlvar(t *Type) *Node {
 	if t.Nname != nil && !isblank(t.Nname) {
-		if !(t.Nname.Inlvar != nil) {
+		if t.Nname.Inlvar == nil {
 			Fatal("missing inlvar for %v\n", Nconv(t.Nname, 0))
 		}
 		return t.Nname.Inlvar
@@ -524,7 +524,7 @@ var inlgen int
 // parameters.
 func mkinlcall1(np **Node, fn *Node, isddd int) {
 	var i int
-	var chkargcount int
+	var chkargcount bool
 	var n *Node
 	var call *Node
 	var saveinlfn *Node
@@ -535,7 +535,7 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	var ninit *NodeList
 	var body *NodeList
 	var t *Type
-	var variadic int
+	var variadic bool
 	var varargcount int
 	var multiret int
 	var vararg *Node
@@ -623,10 +623,10 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 		// method call with a receiver.
 		t = getthisx(fn.Type).Type
 
-		if t != nil && t.Nname != nil && !isblank(t.Nname) && !(t.Nname.Inlvar != nil) {
+		if t != nil && t.Nname != nil && !isblank(t.Nname) && t.Nname.Inlvar == nil {
 			Fatal("missing inlvar for %v\n", Nconv(t.Nname, 0))
 		}
-		if !(n.Left.Left != nil) {
+		if n.Left.Left == nil {
 			Fatal("method call without receiver: %v", Nconv(n, obj.FmtSign))
 		}
 		if t == nil {
@@ -640,26 +640,26 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	}
 
 	// check if inlined function is variadic.
-	variadic = 0
+	variadic = false
 
 	varargtype = nil
 	varargcount = 0
 	for t = fn.Type.Type.Down.Down.Type; t != nil; t = t.Down {
 		if t.Isddd != 0 {
-			variadic = 1
+			variadic = true
 			varargtype = t.Type
 		}
 	}
 
 	// but if argument is dotted too forget about variadicity.
-	if variadic != 0 && isddd != 0 {
-		variadic = 0
+	if variadic && isddd != 0 {
+		variadic = false
 	}
 
 	// check if argument is actually a returned tuple from call.
 	multiret = 0
 
-	if n.List != nil && !(n.List.Next != nil) {
+	if n.List != nil && n.List.Next == nil {
 		switch n.List.N.Op {
 		case OCALL,
 			OCALLFUNC,
@@ -671,7 +671,7 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 		}
 	}
 
-	if variadic != 0 {
+	if variadic {
 		varargcount = count(n.List) + multiret
 		if n.Left.Op != ODOTMETH {
 			varargcount -= fn.Type.Thistuple
@@ -688,14 +688,14 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	// TODO: if len(nlist) == 1 but multiple args, check that n->list->n is a call?
 	if fn.Type.Thistuple != 0 && n.Left.Op != ODOTMETH {
 		// non-method call to method
-		if !(n.List != nil) {
+		if n.List == nil {
 			Fatal("non-method call to method without first arg: %v", Nconv(n, obj.FmtSign))
 		}
 
 		// append receiver inlvar to LHS.
 		t = getthisx(fn.Type).Type
 
-		if t != nil && t.Nname != nil && !isblank(t.Nname) && !(t.Nname.Inlvar != nil) {
+		if t != nil && t.Nname != nil && !isblank(t.Nname) && t.Nname.Inlvar == nil {
 			Fatal("missing inlvar for %v\n", Nconv(t.Nname, 0))
 		}
 		if t == nil {
@@ -706,14 +706,14 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	}
 
 	// append ordinary arguments to LHS.
-	chkargcount = bool2int(n.List != nil && n.List.Next != nil)
+	chkargcount = n.List != nil && n.List.Next != nil
 
 	vararg = nil  // the slice argument to a variadic call
 	varargs = nil // the list of LHS names to put in vararg.
-	if !(chkargcount != 0) {
+	if !chkargcount {
 		// 0 or 1 expression on RHS.
 		for t = getinargx(fn.Type).Type; t != nil; t = t.Down {
-			if variadic != 0 && t.Isddd != 0 {
+			if variadic && t.Isddd != 0 {
 				vararg = tinlvar(t)
 				for i = 0; i < varargcount && ll != nil; i++ {
 					m = argvar(varargtype, i)
@@ -729,10 +729,10 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	} else {
 		// match arguments except final variadic (unless the call is dotted itself)
 		for t = getinargx(fn.Type).Type; t != nil; {
-			if !(ll != nil) {
+			if ll == nil {
 				break
 			}
-			if variadic != 0 && t.Isddd != 0 {
+			if variadic && t.Isddd != 0 {
 				break
 			}
 			as.List = list(as.List, tinlvar(t))
@@ -741,7 +741,7 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 		}
 
 		// match varargcount arguments with variadic parameters.
-		if variadic != 0 && t != nil && t.Isddd != 0 {
+		if variadic && t != nil && t.Isddd != 0 {
 			vararg = tinlvar(t)
 			for i = 0; i < varargcount && ll != nil; i++ {
 				m = argvar(varargtype, i)
@@ -766,9 +766,9 @@ func mkinlcall1(np **Node, fn *Node, isddd int) {
 	}
 
 	// turn the variadic args into a slice.
-	if variadic != 0 {
+	if variadic {
 		as = Nod(OAS, vararg, nil)
-		if !(varargcount != 0) {
+		if varargcount == 0 {
 			as.Right = nodnil()
 			as.Right.Type = varargtype
 		} else {
@@ -1019,7 +1019,7 @@ func setlnolist(ll *NodeList, lno int) {
 }
 
 func setlno(n *Node, lno int) {
-	if !(n != nil) {
+	if n == nil {
 		return
 	}
 

src/cmd/internal/gc/lex.go

@@ -504,20 +504,20 @@ func arsize(b *obj.Biobuf, name string) int {
 	return i
 }
 
-func skiptopkgdef(b *obj.Biobuf) int {
+func skiptopkgdef(b *obj.Biobuf) bool {
 	var p string
 	var sz int
 
 	/* archive header */
 	p = obj.Brdline(b, '\n')
 	if p == "" {
-		return 0
+		return false
 	}
 	if obj.Blinelen(b) != 8 {
-		return 0
+		return false
 	}
 	if p != "!<arch>\n" {
-		return 0
+		return false
 	}
 
 	/* symbol table may be first; skip it */
@@ -533,9 +533,9 @@ func skiptopkgdef(b *obj.Biobuf) int {
 	sz = arsize(b, "__.PKGDEF")
 
 	if sz <= 0 {
-		return 0
+		return false
 	}
-	return 1
+	return true
 }
 
 func addidir(dir string) {
@@ -560,7 +560,7 @@ func islocalname(name *Strlit) bool {
 		strings.HasPrefix(name.S, "../") || name.S == ".."
 }
 
-func findpkg(name *Strlit) int {
+func findpkg(name *Strlit) bool {
 	var p *Idir
 	var q string
 	var suffix string
@@ -568,7 +568,7 @@ func findpkg(name *Strlit) int {
 
 	if islocalname(name) {
 		if safemode != 0 || nolocalimports != 0 {
-			return 0
+			return false
 		}
 
 		// try .a before .6.  important for building libraries:
@@ -577,13 +577,13 @@ func findpkg(name *Strlit) int {
 		namebuf = fmt.Sprintf("%v.a", Zconv(name, 0))
 
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
 		namebuf = fmt.Sprintf("%v.%c", Zconv(name, 0), Thearch.Thechar)
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
-		return 0
+		return false
 	}
 
 	// local imports should be canonicalized already.
@@ -592,17 +592,17 @@ func findpkg(name *Strlit) int {
 	_ = q
 	if path.Clean(name.S) != name.S {
 		Yyerror("non-canonical import path %v (should be %s)", Zconv(name, 0), q)
-		return 0
+		return false
 	}
 
 	for p = idirs; p != nil; p = p.link {
 		namebuf = fmt.Sprintf("%s/%v.a", p.dir, Zconv(name, 0))
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
 		namebuf = fmt.Sprintf("%s/%v.%c", p.dir, Zconv(name, 0), Thearch.Thechar)
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
 	}
 
@@ -619,15 +619,15 @@ func findpkg(name *Strlit) int {
 
 		namebuf = fmt.Sprintf("%s/pkg/%s_%s%s%s/%v.a", goroot, goos, goarch, suffixsep, suffix, Zconv(name, 0))
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
 		namebuf = fmt.Sprintf("%s/pkg/%s_%s%s%s/%v.%c", goroot, goos, goarch, suffixsep, suffix, Zconv(name, 0), Thearch.Thechar)
 		if obj.Access(namebuf, 0) >= 0 {
-			return 1
+			return true
 		}
 	}
 
-	return 0
+	return false
 }
 
 func fakeimport() {
@@ -714,7 +714,7 @@ func importfile(f *Val, line int) {
 		}
 	}
 
-	if !(findpkg(path_) != 0) {
+	if !findpkg(path_) {
 		Yyerror("can't find import: \"%v\"", Zconv(f.U.Sval, 0))
 		errorexit()
 	}
@@ -748,7 +748,7 @@ func importfile(f *Val, line int) {
 
 	n = len(namebuf)
 	if n > 2 && namebuf[n-2] == '.' && namebuf[n-1] == 'a' {
-		if !(skiptopkgdef(imp) != 0) {
+		if !skiptopkgdef(imp) {
 			Yyerror("import %s: not a package file", file)
 			errorexit()
 		}
@@ -946,7 +946,7 @@ l0:
 
 		for {
 
-			if escchar('"', &escflag, &v) != 0 {
+			if escchar('"', &escflag, &v) {
 				break
 			}
 			if v < utf8.RuneSelf || escflag != 0 {
@@ -988,12 +988,12 @@ l0:
 
 		/* '.' */
 	case '\'':
-		if escchar('\'', &escflag, &v) != 0 {
+		if escchar('\'', &escflag, &v) {
 			Yyerror("empty character literal or unescaped ' in character literal")
 			v = '\''
 		}
 
-		if !(escchar('\'', &escflag, &v) != 0) {
+		if !escchar('\'', &escflag, &v) {
 			Yyerror("missing '")
 			ungetc(int(v))
 		}
@@ -1629,7 +1629,7 @@ go_:
 	}
 
 	if verb == "go:linkname" {
-		if !(imported_unsafe != 0) {
+		if imported_unsafe == 0 {
 			Yyerror("//go:linkname only allowed in Go files that import \"unsafe\"")
 		}
 		f := strings.Fields(cmd)
@@ -1658,7 +1658,7 @@ go_:
 	}
 
 	if verb == "go:nowritebarrier" {
-		if !(compiling_runtime != 0) {
+		if compiling_runtime == 0 {
 			Yyerror("//go:nowritebarrier only allowed in runtime")
 		}
 		nowritebarrier = true
@@ -1961,7 +1961,7 @@ func getr() int32 {
 	}
 }
 
-func escchar(e int, escflg *int, val *int64) int {
+func escchar(e int, escflg *int, val *int64) bool {
 	var i int
 	var u int
 	var c int
@@ -1973,21 +1973,21 @@ func escchar(e int, escflg *int, val *int64) int {
 	switch c {
 	case EOF:
 		Yyerror("eof in string")
-		return 1
+		return true
 
 	case '\n':
 		Yyerror("newline in string")
-		return 1
+		return true
 
 	case '\\':
 		break
 
 	default:
 		if c == e {
-			return 1
+			return true
 		}
 		*val = int64(c)
-		return 0
+		return false
 	}
 
 	u = 0
@@ -2043,7 +2043,7 @@ func escchar(e int, escflg *int, val *int64) int {
 	}
 
 	*val = int64(c)
-	return 0
+	return false
 
 hex:
 	l = 0
@@ -2075,7 +2075,7 @@ hex:
 	}
 
 	*val = l
-	return 0
+	return false
 
 oct:
 	l = int64(c) - '0'
@@ -2095,7 +2095,7 @@ oct:
 	}
 
 	*val = l
-	return 0
+	return false
 }
 
 var syms = []struct {
@@ -2530,12 +2530,12 @@ func lexinit() {
 	idealbool = typ(TBOOL)
 
 	s = Pkglookup("true", builtinpkg)
-	s.Def = Nodbool(1)
+	s.Def = Nodbool(true)
 	s.Def.Sym = Lookup("true")
 	s.Def.Type = idealbool
 
 	s = Pkglookup("false", builtinpkg)
-	s.Def = Nodbool(0)
+	s.Def = Nodbool(false)
 	s.Def.Sym = Lookup("false")
 	s.Def.Type = idealbool
 
@@ -2704,14 +2704,14 @@ func lexfini() {
 
 	s = Lookup("true")
 	if s.Def == nil {
-		s.Def = Nodbool(1)
+		s.Def = Nodbool(true)
 		s.Def.Sym = s
 		s.Origpkg = builtinpkg
 	}
 
 	s = Lookup("false")
 	if s.Def == nil {
-		s.Def = Nodbool(0)
+		s.Def = Nodbool(false)
 		s.Def.Sym = s
 		s.Origpkg = builtinpkg
 	}
@@ -3163,7 +3163,7 @@ func mkpackage(pkgname string) {
 					// leave s->block set to cause redeclaration
 					// errors if a conflicting top-level name is
 					// introduced by a different file.
-					if !(s.Def.Used != 0) && !(nsyntaxerrors != 0) {
+					if s.Def.Used == 0 && nsyntaxerrors == 0 {
 						pkgnotused(int(s.Def.Lineno), s.Def.Pkg.Path, s.Name)
 					}
 					s.Def = nil
@@ -3173,7 +3173,7 @@ func mkpackage(pkgname string) {
 				if s.Def.Sym != s {
 					// throw away top-level name left over
 					// from previous import . "x"
-					if s.Def.Pack != nil && !(s.Def.Pack.Used != 0) && !(nsyntaxerrors != 0) {
+					if s.Def.Pack != nil && s.Def.Pack.Used == 0 && nsyntaxerrors == 0 {
 						pkgnotused(int(s.Def.Pack.Lineno), s.Def.Pack.Pkg.Path, "")
 						s.Def.Pack.Used = 1
 					}

src/cmd/internal/gc/mparith2.go

@@ -44,7 +44,7 @@ func mplsh(a *Mpint, quiet int) {
 	}
 
 	a.Ovf = uint8(c)
-	if a.Ovf != 0 && !(quiet != 0) {
+	if a.Ovf != 0 && quiet == 0 {
 		Yyerror("constant shift overflow")
 	}
 }
@@ -59,7 +59,7 @@ func mplshw(a *Mpint, quiet int) {
 	i = Mpprec - 1
 	if a.A[i] != 0 {
 		a.Ovf = 1
-		if !(quiet != 0) {
+		if quiet == 0 {
 			Yyerror("constant shift overflow")
 		}
 	}
@@ -223,7 +223,7 @@ func mpaddfixfix(a *Mpint, b *Mpint, quiet int) {
 	}
 
 	a.Ovf = uint8(c)
-	if a.Ovf != 0 && !(quiet != 0) {
+	if a.Ovf != 0 && quiet == 0 {
 		Yyerror("constant addition overflow")
 	}
 
@@ -663,15 +663,15 @@ func mpdivmodfixfix(q *Mpint, r *Mpint, n *Mpint, d *Mpint) {
 	q.Neg = uint8(ns ^ ds)
 }
 
-func mpiszero(a *Mpint) int {
+func mpiszero(a *Mpint) bool {
 	var i int
 
 	for i = Mpprec - 1; i >= 0; i-- {
 		if a.A[i] != 0 {
-			return 0
+			return false
 		}
 	}
-	return 1
+	return true
 }
 
 func mpdivfract(a *Mpint, b *Mpint) {
@@ -694,7 +694,7 @@ func mpdivfract(a *Mpint, b *Mpint) {
 		for j = 0; j < Mpscale; j++ {
 			x <<= 1
 			if mpcmp(&d, &n) <= 0 {
-				if !(mpiszero(&d) != 0) {
+				if !mpiszero(&d) {
 					x |= 1
 				}
 				mpsubfixfix(&n, &d)

src/cmd/internal/gc/pgen.go

@@ -272,7 +272,7 @@ func allocauto(ptxt *obj.Prog) {
 	ll = Curfn.Dcl
 
 	n = ll.N
-	if n.Class == PAUTO && n.Op == ONAME && !(n.Used != 0) {
+	if n.Class == PAUTO && n.Op == ONAME && n.Used == 0 {
 		// No locals used at all
 		Curfn.Dcl = nil
 
@@ -282,7 +282,7 @@ func allocauto(ptxt *obj.Prog) {
 
 	for ll = Curfn.Dcl; ll.Next != nil; ll = ll.Next {
 		n = ll.Next.N
-		if n.Class == PAUTO && n.Op == ONAME && !(n.Used != 0) {
+		if n.Class == PAUTO && n.Op == ONAME && n.Used == 0 {
 			ll.Next = nil
 			Curfn.Dcl.End = ll
 			break
@@ -360,12 +360,12 @@ func Cgen_checknil(n *Node) {
 	}
 
 	// Ideally we wouldn't see any integer types here, but we do.
-	if n.Type == nil || (!(Isptr[n.Type.Etype] != 0) && !(Isint[n.Type.Etype] != 0) && n.Type.Etype != TUNSAFEPTR) {
+	if n.Type == nil || (Isptr[n.Type.Etype] == 0 && Isint[n.Type.Etype] == 0 && n.Type.Etype != TUNSAFEPTR) {
 		Dump("checknil", n)
 		Fatal("bad checknil")
 	}
 
-	if ((Thearch.Thechar == '5' || Thearch.Thechar == '9') && n.Op != OREGISTER) || !(n.Addable != 0) || n.Op == OLITERAL {
+	if ((Thearch.Thechar == '5' || Thearch.Thechar == '9') && n.Op != OREGISTER) || n.Addable == 0 || n.Op == OLITERAL {
 		Thearch.Regalloc(&reg, Types[Tptr], n)
 		Thearch.Cgen(n, &reg)
 		Thearch.Gins(obj.ACHECKNIL, &reg, nil)
@@ -478,7 +478,7 @@ func compile(fn *Node) {
 	if fn.Wrapper != 0 {
 		ptxt.From3.Offset |= obj.WRAPPER
 	}
-	if fn.Needctxt != 0 {
+	if fn.Needctxt {
 		ptxt.From3.Offset |= obj.NEEDCTXT
 	}
 	if fn.Nosplit {
@@ -557,7 +557,7 @@ func compile(fn *Node) {
 	Pc.Lineno = lineno
 
 	fixjmp(ptxt)
-	if !(Debug['N'] != 0) || Debug['R'] != 0 || Debug['P'] != 0 {
+	if Debug['N'] == 0 || Debug['R'] != 0 || Debug['P'] != 0 {
 		regopt(ptxt)
 		nilopt(ptxt)
 	}

src/cmd/internal/gc/plive.go

@@ -183,18 +183,13 @@ func printblock(bb *BasicBlock) {
 // are two criteria for termination.  If the end of basic block is reached a
 // value of zero is returned.  If the callback returns a non-zero value, the
 // iteration is stopped and the value of the callback is returned.
-func blockany(bb *BasicBlock, callback func(*obj.Prog) int) int {
-	var p *obj.Prog
-	var result int
-
-	for p = bb.last; p != nil; p = p.Opt.(*obj.Prog) {
-		result = callback(p)
-		if result != 0 {
-			return result
+func blockany(bb *BasicBlock, f func(*obj.Prog) bool) bool {
+	for p := bb.last; p != nil; p = p.Opt.(*obj.Prog) {
+		if f(p) {
+			return true
 		}
 	}
-
-	return 0
+	return false
 }
 
 // Collects and returns and array of Node*s for functions arguments and local
@@ -303,7 +298,7 @@ func iscall(prog *obj.Prog, name *obj.LSym) bool {
 
 var isselectcommcasecall_names [5]*obj.LSym
 
-func isselectcommcasecall(prog *obj.Prog) int {
+func isselectcommcasecall(prog *obj.Prog) bool {
 	var i int32
 
 	if isselectcommcasecall_names[0] == nil {
@@ -315,41 +310,41 @@ func isselectcommcasecall(prog *obj.Prog) int {
 
 	for i = 0; isselectcommcasecall_names[i] != nil; i++ {
 		if iscall(prog, isselectcommcasecall_names[i]) {
-			return 1
+			return true
 		}
 	}
-	return 0
+	return false
 }
 
 // Returns true for call instructions that target runtime·newselect.
 
 var isnewselect_sym *obj.LSym
 
-func isnewselect(prog *obj.Prog) int {
+func isnewselect(prog *obj.Prog) bool {
 	if isnewselect_sym == nil {
 		isnewselect_sym = Linksym(Pkglookup("newselect", Runtimepkg))
 	}
-	return bool2int(iscall(prog, isnewselect_sym))
+	return iscall(prog, isnewselect_sym)
 }
 
 // Returns true for call instructions that target runtime·selectgo.
 
 var isselectgocall_sym *obj.LSym
 
-func isselectgocall(prog *obj.Prog) int {
+func isselectgocall(prog *obj.Prog) bool {
 	if isselectgocall_sym == nil {
 		isselectgocall_sym = Linksym(Pkglookup("selectgo", Runtimepkg))
 	}
-	return bool2int(iscall(prog, isselectgocall_sym))
+	return iscall(prog, isselectgocall_sym)
 }
 
 var isdeferreturn_sym *obj.LSym
 
-func isdeferreturn(prog *obj.Prog) int {
+func isdeferreturn(prog *obj.Prog) bool {
 	if isdeferreturn_sym == nil {
 		isdeferreturn_sym = Linksym(Pkglookup("deferreturn", Runtimepkg))
 	}
-	return bool2int(iscall(prog, isdeferreturn_sym))
+	return iscall(prog, isdeferreturn_sym)
 }
 
 // Walk backwards from a runtime·selectgo call up to its immediately dominating
@@ -366,7 +361,7 @@ func addselectgosucc(selectgo *BasicBlock) {
 			Fatal("selectgo does not have a newselect")
 		}
 		pred = pred.pred[0]
-		if blockany(pred, isselectcommcasecall) != 0 {
+		if blockany(pred, isselectcommcasecall) {
 			// A select comm case block should have exactly one
 			// successor.
 			if len(pred.succ) != 1 {
@@ -386,7 +381,7 @@ func addselectgosucc(selectgo *BasicBlock) {
 			addedge(selectgo, succ)
 		}
 
-		if blockany(pred, isnewselect) != 0 {
+		if blockany(pred, isnewselect) {
 			// Reached the matching newselect.
 			break
 		}
@@ -451,7 +446,7 @@ func newcfg(firstp *obj.Prog) []*BasicBlock {
 				p.Link.Opt = newblock(p.Link)
 				cfg = append(cfg, p.Link.Opt.(*BasicBlock))
 			}
-		} else if isselectcommcasecall(p) != 0 || isselectgocall(p) != 0 {
+		} else if isselectcommcasecall(p) || isselectgocall(p) {
 			// Accommodate implicit selectgo control flow.
 			if p.Link.Opt == nil {
 				p.Link.Opt = newblock(p.Link)
@@ -478,7 +473,7 @@ func newcfg(firstp *obj.Prog) []*BasicBlock {
 			}
 
 			// Collect basic blocks with selectgo calls.
-			if isselectgocall(p) != 0 {
+			if isselectgocall(p) {
 				selectgo = append(selectgo, bb)
 			}
 		}
@@ -627,7 +622,7 @@ func progeffects(prog *obj.Prog, vars []*Node, uevar *Bvec, varkill *Bvec, avari
 			// non-tail-call return instructions; see note above
 			// the for loop for details.
 			case PPARAMOUT:
-				if !(node.Addrtaken != 0) && prog.To.Type == obj.TYPE_NONE {
+				if node.Addrtaken == 0 && prog.To.Type == obj.TYPE_NONE {
 					bvset(uevar, i)
 				}
 			}
@@ -674,7 +669,7 @@ func progeffects(prog *obj.Prog, vars []*Node, uevar *Bvec, varkill *Bvec, avari
 						bvset(uevar, pos)
 					}
 					if info.Flags&LeftWrite != 0 {
-						if from.Node != nil && !(Isfat(((from.Node).(*Node)).Type) != 0) {
+						if from.Node != nil && !Isfat(((from.Node).(*Node)).Type) {
 							bvset(varkill, pos)
 						}
 					}
@@ -718,7 +713,7 @@ Next:
 						bvset(uevar, pos)
 					}
 					if info.Flags&RightWrite != 0 {
-						if to.Node != nil && (!(Isfat(((to.Node).(*Node)).Type) != 0) || prog.As == obj.AVARDEF) {
+						if to.Node != nil && (!Isfat(((to.Node).(*Node)).Type) || prog.As == obj.AVARDEF) {
 							bvset(varkill, pos)
 						}
 					}
@@ -1050,7 +1045,7 @@ func twobitwalktype1(t *Type, xoffset *int64, bv *Bvec) {
 		if t.Bound < -1 {
 			Fatal("twobitwalktype1: invalid bound, %v", Tconv(t, 0))
 		}
-		if Isslice(t) != 0 {
+		if Isslice(t) {
 			// struct { byte *array; uintgo len; uintgo cap; }
 			if *xoffset&int64(Widthptr-1) != 0 {
 				Fatal("twobitwalktype1: invalid TARRAY alignment, %v", Tconv(t, 0))
@@ -1101,7 +1096,7 @@ func twobitlivepointermap(lv *Liveness, liveout *Bvec, vars []*Node, args *Bvec,
 
 	for i = 0; ; i++ {
 		i = int32(bvnext(liveout, i))
-		if !(i >= 0) {
+		if i < 0 {
 			break
 		}
 		node = vars[i]
@@ -1163,8 +1158,8 @@ func newpcdataprog(prog *obj.Prog, index int32) *obj.Prog {
 
 // Returns true for instructions that are safe points that must be annotated
 // with liveness information.
-func issafepoint(prog *obj.Prog) int {
-	return bool2int(prog.As == obj.ATEXT || prog.As == obj.ACALL)
+func issafepoint(prog *obj.Prog) bool {
+	return prog.As == obj.ATEXT || prog.As == obj.ACALL
 }
 
 // Initializes the sets for solving the live variables.  Visits all the
@@ -1332,7 +1327,7 @@ func livenesssolve(lv *Liveness) {
 
 // This function is slow but it is only used for generating debug prints.
 // Check whether n is marked live in args/locals.
-func islive(n *Node, args *Bvec, locals *Bvec) int {
+func islive(n *Node, args *Bvec, locals *Bvec) bool {
 	var i int
 
 	switch n.Class {
@@ -1340,19 +1335,19 @@ func islive(n *Node, args *Bvec, locals *Bvec) int {
 		PPARAMOUT:
 		for i = 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
 			if bvget(args, int32(n.Xoffset/int64(Widthptr)*obj.BitsPerPointer+int64(i))) != 0 {
-				return 1
+				return true
 			}
 		}
 
 	case PAUTO:
 		for i = 0; int64(i) < n.Type.Width/int64(Widthptr)*obj.BitsPerPointer; i++ {
 			if bvget(locals, int32((n.Xoffset+stkptrsize)/int64(Widthptr)*obj.BitsPerPointer+int64(i))) != 0 {
-				return 1
+				return true
 			}
 		}
 	}
 
-	return 0
+	return false
 }
 
 // Visits all instructions in a basic block and computes a bit vector of live
@@ -1427,21 +1422,21 @@ func livenessepilogue(lv *Liveness) {
 			bvor(any, any, avarinit)
 			bvor(all, all, avarinit)
 
-			if issafepoint(p) != 0 {
+			if issafepoint(p) {
 				// Annotate ambiguously live variables so that they can
 				// be zeroed at function entry.
 				// livein and liveout are dead here and used as temporaries.
 				bvresetall(livein)
 
 				bvandnot(liveout, any, all)
-				if !(bvisempty(liveout) != 0) {
+				if !bvisempty(liveout) {
 					for pos = 0; pos < liveout.n; pos++ {
-						if !(bvget(liveout, pos) != 0) {
+						if bvget(liveout, pos) == 0 {
 							continue
 						}
 						bvset(all, pos) // silence future warnings in this block
 						n = lv.vars[pos]
-						if !(n.Needzero != 0) {
+						if n.Needzero == 0 {
 							n.Needzero = 1
 							if debuglive >= 1 {
 								Warnl(int(p.Lineno), "%v: %v is ambiguously live", Nconv(Curfn.Nname, 0), Nconv(n, obj.FmtLong))
@@ -1517,7 +1512,7 @@ func livenessepilogue(lv *Liveness) {
 			bvcopy(liveout, livein)
 			bvandnot(livein, liveout, varkill)
 			bvor(livein, livein, uevar)
-			if debuglive >= 3 && issafepoint(p) != 0 {
+			if debuglive >= 3 && issafepoint(p) {
 				fmt.Printf("%v\n", p)
 				printvars("uevar", uevar, lv.vars)
 				printvars("varkill", varkill, lv.vars)
@@ -1525,7 +1520,7 @@ func livenessepilogue(lv *Liveness) {
 				printvars("liveout", liveout, lv.vars)
 			}
 
-			if issafepoint(p) != 0 {
+			if issafepoint(p) {
 				// Found an interesting instruction, record the
 				// corresponding liveness information.
 
@@ -1534,7 +1529,7 @@ func livenessepilogue(lv *Liveness) {
 				// input parameters.
 				if p.As == obj.ATEXT {
 					for j = 0; j < liveout.n; j++ {
-						if !(bvget(liveout, j) != 0) {
+						if bvget(liveout, j) == 0 {
 							continue
 						}
 						n = lv.vars[j]
@@ -1574,7 +1569,7 @@ func livenessepilogue(lv *Liveness) {
 					numlive = 0
 					for j = 0; j < int32(len(lv.vars)); j++ {
 						n = lv.vars[j]
-						if islive(n, args, locals) != 0 {
+						if islive(n, args, locals) {
 							fmt_ += fmt.Sprintf(" %v", Nconv(n, 0))
 							numlive++
 						}
@@ -1592,7 +1587,7 @@ func livenessepilogue(lv *Liveness) {
 				// Only CALL instructions need a PCDATA annotation.
 				// The TEXT instruction annotation is implicit.
 				if p.As == obj.ACALL {
-					if isdeferreturn(p) != 0 {
+					if isdeferreturn(p) {
 						// runtime.deferreturn modifies its return address to return
 						// back to the CALL, not to the subsequent instruction.
 						// Because the return comes back one instruction early,
@@ -1760,11 +1755,11 @@ func printbitset(printed int, name string, vars []*Node, bits *Bvec) int {
 
 	started = 0
 	for i = 0; i < len(vars); i++ {
-		if !(bvget(bits, int32(i)) != 0) {
+		if bvget(bits, int32(i)) == 0 {
 			continue
 		}
-		if !(started != 0) {
-			if !(printed != 0) {
+		if started == 0 {
+			if printed == 0 {
 				fmt.Printf("\t")
 			} else {
 				fmt.Printf(" ")
@@ -1856,14 +1851,14 @@ func livenessprintdebug(lv *Liveness) {
 			if printed != 0 {
 				fmt.Printf("\n")
 			}
-			if issafepoint(p) != 0 {
+			if issafepoint(p) {
 				args = lv.argslivepointers[pcdata]
 				locals = lv.livepointers[pcdata]
 				fmt.Printf("\tlive=")
 				printed = 0
 				for j = 0; j < len(lv.vars); j++ {
 					n = lv.vars[j]
-					if islive(n, args, locals) != 0 {
+					if islive(n, args, locals) {
 						tmp9 := printed
 						printed++
 						if tmp9 != 0 {

src/cmd/internal/gc/popt.go

@@ -179,7 +179,7 @@ void proginfo(ProgInfo*, Prog*);
 
 var noreturn_symlist [10]*Sym
 
-func Noreturn(p *obj.Prog) int {
+func Noreturn(p *obj.Prog) bool {
 	var s *Sym
 	var i int
 
@@ -195,18 +195,18 @@ func Noreturn(p *obj.Prog) int {
 	}
 
 	if p.To.Node == nil {
-		return 0
+		return false
 	}
 	s = ((p.To.Node).(*Node)).Sym
 	if s == nil {
-		return 0
+		return false
 	}
 	for i = 0; noreturn_symlist[i] != nil; i++ {
 		if s == noreturn_symlist[i] {
-			return 1
+			return true
 		}
 	}
-	return 0
+	return false
 }
 
 // JMP chasing and removal.
@@ -325,7 +325,7 @@ func fixjmp(firstp *obj.Prog) {
 
 	// pass 4: elide JMP to next instruction.
 	// only safe if there are no jumps to JMPs anymore.
-	if !(jmploop != 0) {
+	if jmploop == 0 {
 		last = nil
 		for p = firstp; p != nil; p = p.Link {
 			if p.As == obj.AJMP && p.To.Type == obj.TYPE_BRANCH && p.To.U.Branch == p.Link {
@@ -434,7 +434,7 @@ func Flowstart(firstp *obj.Prog, newData func() interface{}) *Graph {
 	for f = start; f != nil; f = f.Link {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
-		if !(info.Flags&Break != 0) {
+		if info.Flags&Break == 0 {
 			f1 = f.Link
 			f.S1 = f1
 			f1.P1 = f
@@ -492,11 +492,11 @@ func postorder(r *Flow, rpo2r []*Flow, n int32) int32 {
 
 	r.Rpo = 1
 	r1 = r.S1
-	if r1 != nil && !(r1.Rpo != 0) {
+	if r1 != nil && r1.Rpo == 0 {
 		n = postorder(r1, rpo2r, n)
 	}
 	r1 = r.S2
-	if r1 != nil && !(r1.Rpo != 0) {
+	if r1 != nil && r1.Rpo == 0 {
 		n = postorder(r1, rpo2r, n)
 	}
 	rpo2r[n] = r
@@ -529,26 +529,26 @@ func rpolca(idom []int32, rpo1 int32, rpo2 int32) int32 {
 	return rpo1
 }
 
-func doms(idom []int32, r int32, s int32) int {
+func doms(idom []int32, r int32, s int32) bool {
 	for s > r {
 		s = idom[s]
 	}
-	return bool2int(s == r)
+	return s == r
 }
 
-func loophead(idom []int32, r *Flow) int {
+func loophead(idom []int32, r *Flow) bool {
 	var src int32
 
 	src = r.Rpo
-	if r.P1 != nil && doms(idom, src, r.P1.Rpo) != 0 {
-		return 1
+	if r.P1 != nil && doms(idom, src, r.P1.Rpo) {
+		return true
 	}
 	for r = r.P2; r != nil; r = r.P2link {
-		if doms(idom, src, r.Rpo) != 0 {
-			return 1
+		if doms(idom, src, r.Rpo) {
+			return true
 		}
 	}
-	return 0
+	return false
 }
 
 func loopmark(rpo2r **Flow, head int32, r *Flow) {
@@ -620,7 +620,7 @@ func flowrpo(g *Graph) {
 	for i = 0; i < nr; i++ {
 		r1 = rpo2r[i]
 		r1.Loop++
-		if r1.P2 != nil && loophead(idom, r1) != 0 {
+		if r1.P2 != nil && loophead(idom, r1) {
 			loopmark(&rpo2r[0], i, r1)
 		}
 	}
@@ -718,8 +718,8 @@ func (x startcmp) Less(i, j int) bool {
 }
 
 // Is n available for merging?
-func canmerge(n *Node) int {
-	return bool2int(n.Class == PAUTO && strings.HasPrefix(n.Sym.Name, "autotmp"))
+func canmerge(n *Node) bool {
+	return n.Class == PAUTO && strings.HasPrefix(n.Sym.Name, "autotmp")
 }
 
 func mergetemp(firstp *obj.Prog) {
@@ -757,7 +757,7 @@ func mergetemp(firstp *obj.Prog) {
 	// Build list of all mergeable variables.
 	nvar = 0
 	for l = Curfn.Dcl; l != nil; l = l.Next {
-		if canmerge(l.N) != 0 {
+		if canmerge(l.N) {
 			nvar++
 		}
 	}
@@ -766,7 +766,7 @@ func mergetemp(firstp *obj.Prog) {
 	nvar = 0
 	for l = Curfn.Dcl; l != nil; l = l.Next {
 		n = l.N
-		if canmerge(n) != 0 {
+		if canmerge(n) {
 			v = &var_[nvar]
 			nvar++
 			n.Opt = v
@@ -826,9 +826,9 @@ func mergetemp(firstp *obj.Prog) {
 		if f != nil && f.Data.(*Flow) == nil {
 			p = f.Prog
 			Thearch.Proginfo(&info, p)
-			if p.To.Node == v.node && (info.Flags&RightWrite != 0) && !(info.Flags&RightRead != 0) {
+			if p.To.Node == v.node && (info.Flags&RightWrite != 0) && info.Flags&RightRead == 0 {
 				p.As = obj.ANOP
-				p.To = obj.Zprog.To
+				p.To = obj.Addr{}
 				v.removed = 1
 				if debugmerge > 0 && Debug['v'] != 0 {
 					fmt.Printf("drop write-only %v\n", Sconv(v.node.Sym, 0))
@@ -851,7 +851,7 @@ func mergetemp(firstp *obj.Prog) {
 			const (
 				SizeAny = SizeB | SizeW | SizeL | SizeQ | SizeF | SizeD
 			)
-			if p.From.Node == v.node && p1.To.Node == v.node && (info.Flags&Move != 0) && !((info.Flags|info1.Flags)&(LeftAddr|RightAddr) != 0) && info.Flags&SizeAny == info1.Flags&SizeAny {
+			if p.From.Node == v.node && p1.To.Node == v.node && (info.Flags&Move != 0) && (info.Flags|info1.Flags)&(LeftAddr|RightAddr) == 0 && info.Flags&SizeAny == info1.Flags&SizeAny {
 				p1.From = p.From
 				Thearch.Excise(f)
 				v.removed = 1
@@ -1010,7 +1010,7 @@ func mergetemp(firstp *obj.Prog) {
 	// Delete merged nodes from declaration list.
 	for lp = &Curfn.Dcl; ; {
 		l = *lp
-		if !(l != nil) {
+		if l == nil {
 			break
 		}
 
@@ -1126,11 +1126,11 @@ func nilopt(firstp *obj.Prog) {
 	nkill = 0
 	for f = g.Start; f != nil; f = f.Link {
 		p = f.Prog
-		if p.As != obj.ACHECKNIL || !(Thearch.Regtyp(&p.From) != 0) {
+		if p.As != obj.ACHECKNIL || !Thearch.Regtyp(&p.From) {
 			continue
 		}
 		ncheck++
-		if Thearch.Stackaddr(&p.From) != 0 {
+		if Thearch.Stackaddr(&p.From) {
 			if Debug_checknil != 0 && p.Lineno > 1 {
 				Warnl(int(p.Lineno), "removed nil check of SP address")
 			}
@@ -1177,13 +1177,13 @@ func nilwalkback(fcheck *Flow) {
 	for f = fcheck; f != nil; f = Uniqp(f) {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
-		if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) != 0 {
+		if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) {
 			// Found initialization of value we're checking for nil.
 			// without first finding the check, so this one is unchecked.
 			return
 		}
 
-		if f != fcheck && p.As == obj.ACHECKNIL && Thearch.Sameaddr(&p.From, &fcheck.Prog.From) != 0 {
+		if f != fcheck && p.As == obj.ACHECKNIL && Thearch.Sameaddr(&p.From, &fcheck.Prog.From) {
 			fcheck.Data = &killed
 			return
 		}
@@ -1249,12 +1249,12 @@ func nilwalkfwd(fcheck *Flow) {
 		p = f.Prog
 		Thearch.Proginfo(&info, p)
 
-		if (info.Flags&LeftRead != 0) && Thearch.Smallindir(&p.From, &fcheck.Prog.From) != 0 {
+		if (info.Flags&LeftRead != 0) && Thearch.Smallindir(&p.From, &fcheck.Prog.From) {
 			fcheck.Data = &killed
 			return
 		}
 
-		if (info.Flags&(RightRead|RightWrite) != 0) && Thearch.Smallindir(&p.To, &fcheck.Prog.From) != 0 {
+		if (info.Flags&(RightRead|RightWrite) != 0) && Thearch.Smallindir(&p.To, &fcheck.Prog.From) {
 			fcheck.Data = &killed
 			return
 		}
@@ -1265,12 +1265,12 @@ func nilwalkfwd(fcheck *Flow) {
 		}
 
 		// Stop if value is lost.
-		if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) != 0 {
+		if (info.Flags&RightWrite != 0) && Thearch.Sameaddr(&p.To, &fcheck.Prog.From) {
 			return
 		}
 
 		// Stop if memory write.
-		if (info.Flags&RightWrite != 0) && !(Thearch.Regtyp(&p.To) != 0) {
+		if (info.Flags&RightWrite != 0) && !Thearch.Regtyp(&p.To) {
 			return
 		}
 

src/cmd/internal/gc/racewalk.go

@@ -30,27 +30,27 @@ var omit_pkgs = []string{"runtime", "runtime/race"}
 // Memory accesses in the packages are either uninteresting or will cause false positives.
 var noinst_pkgs = []string{"sync", "sync/atomic"}
 
-func ispkgin(pkgs []string) int {
+func ispkgin(pkgs []string) bool {
 	var i int
 
 	if myimportpath != "" {
 		for i = 0; i < len(pkgs); i++ {
 			if myimportpath == pkgs[i] {
-				return 1
+				return true
 			}
 		}
 	}
 
-	return 0
+	return false
 }
 
-func isforkfunc(fn *Node) int {
+func isforkfunc(fn *Node) bool {
 	// Special case for syscall.forkAndExecInChild.
 	// In the child, this function must not acquire any locks, because
 	// they might have been locked at the time of the fork.  This means
 	// no rescheduling, no malloc calls, and no new stack segments.
 	// Race instrumentation does all of the above.
-	return bool2int(myimportpath != "" && myimportpath == "syscall" && fn.Nname.Sym.Name == "forkAndExecInChild")
+	return myimportpath != "" && myimportpath == "syscall" && fn.Nname.Sym.Name == "forkAndExecInChild"
 }
 
 func racewalk(fn *Node) {
@@ -58,11 +58,11 @@ func racewalk(fn *Node) {
 	var nodpc *Node
 	var s string
 
-	if ispkgin(omit_pkgs) != 0 || isforkfunc(fn) != 0 {
+	if ispkgin(omit_pkgs) || isforkfunc(fn) {
 		return
 	}
 
-	if !(ispkgin(noinst_pkgs) != 0) {
+	if !ispkgin(noinst_pkgs) {
 		racewalklist(fn.Nbody, nil)
 
 		// nothing interesting for race detector in fn->enter
@@ -147,7 +147,6 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
 	switch n.Op {
 	default:
 		Fatal("racewalk: unknown node type %v", Oconv(int(n.Op), 0))
-		fallthrough
 
 	case OAS,
 		OAS2FUNC:
@@ -263,7 +262,7 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
 		OLEN,
 		OCAP:
 		racewalknode(&n.Left, init, 0, 0)
-		if Istype(n.Left.Type, TMAP) != 0 {
+		if Istype(n.Left.Type, TMAP) {
 			n1 = Nod(OCONVNOP, n.Left, nil)
 			n1.Type = Ptrto(Types[TUINT8])
 			n1 = Nod(OIND, n1, nil)
@@ -326,9 +325,9 @@ func racewalknode(np **Node, init **NodeList, wr int, skip int) {
 		goto ret
 
 	case OINDEX:
-		if !(Isfixedarray(n.Left.Type) != 0) {
+		if !Isfixedarray(n.Left.Type) {
 			racewalknode(&n.Left, init, 0, 0)
-		} else if !(islvalue(n.Left) != 0) {
+		} else if !islvalue(n.Left) {
 			// index of unaddressable array, like Map[k][i].
 			racewalknode(&n.Left, init, wr, 0)
 
@@ -468,34 +467,34 @@ ret:
 	*np = n
 }
 
-func isartificial(n *Node) int {
+func isartificial(n *Node) bool {
 	// compiler-emitted artificial things that we do not want to instrument,
 	// cant' possibly participate in a data race.
 	if n.Op == ONAME && n.Sym != nil && n.Sym.Name != "" {
 		if n.Sym.Name == "_" {
-			return 1
+			return true
 		}
 
 		// autotmp's are always local
 		if strings.HasPrefix(n.Sym.Name, "autotmp_") {
-			return 1
+			return true
 		}
 
 		// statictmp's are read-only
 		if strings.HasPrefix(n.Sym.Name, "statictmp_") {
-			return 1
+			return true
 		}
 
 		// go.itab is accessed only by the compiler and runtime (assume safe)
 		if n.Sym.Pkg != nil && n.Sym.Pkg.Name != "" && n.Sym.Pkg.Name == "go.itab" {
-			return 1
+			return true
 		}
 	}
 
-	return 0
+	return false
 }
 
-func callinstr(np **Node, init **NodeList, wr int, skip int) int {
+func callinstr(np **Node, init **NodeList, wr int, skip int) bool {
 	var name string
 	var f *Node
 	var b *Node
@@ -510,18 +509,18 @@ func callinstr(np **Node, init **NodeList, wr int, skip int) int {
 	//	  n, n->op, n->type ? n->type->etype : -1, n->class);
 
 	if skip != 0 || n.Type == nil || n.Type.Etype >= TIDEAL {
-		return 0
+		return false
 	}
 	t = n.Type
-	if isartificial(n) != 0 {
-		return 0
+	if isartificial(n) {
+		return false
 	}
 
 	b = outervalue(n)
 
 	// it skips e.g. stores to ... parameter array
-	if isartificial(b) != 0 {
-		return 0
+	if isartificial(b) {
+		return false
 	}
 	class = int(b.Class)
 
@@ -539,7 +538,7 @@ func callinstr(np **Node, init **NodeList, wr int, skip int) int {
 
 		n = treecopy(n)
 		makeaddable(n)
-		if t.Etype == TSTRUCT || Isfixedarray(t) != 0 {
+		if t.Etype == TSTRUCT || Isfixedarray(t) {
 			name = "racereadrange"
 			if wr != 0 {
 				name = "racewriterange"
@@ -554,10 +553,10 @@ func callinstr(np **Node, init **NodeList, wr int, skip int) int {
 		}
 
 		*init = list(*init, f)
-		return 1
+		return true
 	}
 
-	return 0
+	return false
 }
 
 // makeaddable returns a node whose memory location is the
@@ -572,7 +571,7 @@ func makeaddable(n *Node) {
 	// an addressable value.
 	switch n.Op {
 	case OINDEX:
-		if Isfixedarray(n.Left.Type) != 0 {
+		if Isfixedarray(n.Left.Type) {
 			makeaddable(n.Left)
 		}
 
@@ -596,7 +595,7 @@ func uintptraddr(n *Node) *Node {
 	var r *Node
 
 	r = Nod(OADDR, n, nil)
-	r.Bounded = 1
+	r.Bounded = true
 	r = conv(r, Types[TUNSAFEPTR])
 	r = conv(r, Types[TUINTPTR])
 	return r

src/cmd/internal/gc/range.go

@@ -43,7 +43,7 @@ func typecheckrange(n *Node) {
 		}
 	}
 
-	if Isptr[t.Etype] != 0 && Isfixedarray(t.Type) != 0 {
+	if Isptr[t.Etype] != 0 && Isfixedarray(t.Type) {
 		t = t.Type
 	}
 	n.Type = t
@@ -63,7 +63,7 @@ func typecheckrange(n *Node) {
 		t2 = t.Type
 
 	case TCHAN:
-		if !(t.Chan&Crecv != 0) {
+		if t.Chan&Crecv == 0 {
 			Yyerror("invalid operation: range %v (receive from send-only type %v)", Nconv(n.Right, 0), Tconv(n.Right.Type, 0))
 			goto out
 		}
@@ -184,7 +184,6 @@ func walkrange(n *Node) {
 	switch t.Etype {
 	default:
 		Fatal("walkrange")
-		fallthrough
 
 		// Lower n into runtime·memclr if possible, for
 	// fast zeroing of slices and arrays (issue 5373).
@@ -196,8 +195,8 @@ func walkrange(n *Node) {
 	//
 	// in which the evaluation of a is side-effect-free.
 	case TARRAY:
-		if !(Debug['N'] != 0) {
-			if !(flag_race != 0) {
+		if Debug['N'] == 0 {
+			if flag_race == 0 {
 				if v1 != nil {
 					if v2 == nil {
 						if n.Nbody != nil {
@@ -206,10 +205,10 @@ func walkrange(n *Node) {
 									tmp = n.Nbody.N // first statement of body
 									if tmp.Op == OAS {
 										if tmp.Left.Op == OINDEX {
-											if samesafeexpr(tmp.Left.Left, a) != 0 {
-												if samesafeexpr(tmp.Left.Right, v1) != 0 {
+											if samesafeexpr(tmp.Left.Left, a) {
+												if samesafeexpr(tmp.Left.Right, v1) {
 													if t.Type.Width > 0 {
-														if iszero(tmp.Right) != 0 {
+														if iszero(tmp.Right) {
 															// Convert to
 															// if len(a) != 0 {
 															// 	hp = &a[0]
@@ -227,7 +226,7 @@ func walkrange(n *Node) {
 															hp = temp(Ptrto(Types[TUINT8]))
 
 															tmp = Nod(OINDEX, a, Nodintconst(0))
-															tmp.Bounded = 1
+															tmp.Bounded = true
 															tmp = Nod(OADDR, tmp, nil)
 															tmp = Nod(OCONVNOP, tmp, nil)
 															tmp.Type = Ptrto(Types[TUINT8])
@@ -282,7 +281,7 @@ func walkrange(n *Node) {
 		if v2 != nil {
 			hp = temp(Ptrto(n.Type.Type))
 			tmp = Nod(OINDEX, ha, Nodintconst(0))
-			tmp.Bounded = 1
+			tmp.Bounded = true
 			init = list(init, Nod(OAS, hp, Nod(OADDR, tmp, nil)))
 		}
 
@@ -369,7 +368,7 @@ func walkrange(n *Node) {
 		}
 		hb = temp(Types[TBOOL])
 
-		n.Ntest = Nod(ONE, hb, Nodbool(0))
+		n.Ntest = Nod(ONE, hb, Nodbool(false))
 		a = Nod(OAS2RECV, nil, nil)
 		a.Typecheck = 1
 		a.List = list(list1(hv1), hb)

src/cmd/internal/gc/reflect.go

@@ -355,7 +355,7 @@ func methods(t *Type) *Sig {
 	// type stored in interface word
 	it = t
 
-	if !(isdirectiface(it) != 0) {
+	if !isdirectiface(it) {
 		it = Ptrto(t)
 	}
 
@@ -370,10 +370,10 @@ func methods(t *Type) *Sig {
 		if f.Type.Etype != TFUNC || f.Type.Thistuple == 0 {
 			Fatal("non-method on %v method %v %v\n", Tconv(mt, 0), Sconv(f.Sym, 0), Tconv(f, 0))
 		}
-		if !(getthisx(f.Type).Type != nil) {
+		if getthisx(f.Type).Type == nil {
 			Fatal("receiver with no type on %v method %v %v\n", Tconv(mt, 0), Sconv(f.Sym, 0), Tconv(f, 0))
 		}
-		if f.Nointerface != 0 {
+		if f.Nointerface {
 			continue
 		}
 
@@ -391,7 +391,7 @@ func methods(t *Type) *Sig {
 		if Isptr[this.Etype] != 0 && this.Type == t {
 			continue
 		}
-		if Isptr[this.Etype] != 0 && !(Isptr[t.Etype] != 0) && f.Embedded != 2 && !(isifacemethod(f.Type) != 0) {
+		if Isptr[this.Etype] != 0 && Isptr[t.Etype] == 0 && f.Embedded != 2 && !isifacemethod(f.Type) {
 			continue
 		}
 
@@ -412,7 +412,7 @@ func methods(t *Type) *Sig {
 		a.type_ = methodfunc(f.Type, t)
 		a.mtype = methodfunc(f.Type, nil)
 
-		if !(a.isym.Flags&SymSiggen != 0) {
+		if a.isym.Flags&SymSiggen == 0 {
 			a.isym.Flags |= SymSiggen
 			if !Eqtype(this, it) || this.Width < Types[Tptr].Width {
 				compiling_wrappers = 1
@@ -421,7 +421,7 @@ func methods(t *Type) *Sig {
 			}
 		}
 
-		if !(a.tsym.Flags&SymSiggen != 0) {
+		if a.tsym.Flags&SymSiggen == 0 {
 			a.tsym.Flags |= SymSiggen
 			if !Eqtype(this, t) {
 				compiling_wrappers = 1
@@ -489,7 +489,7 @@ func imethods(t *Type) *Sig {
 		// code can refer to it.
 		isym = methodsym(method, t, 0)
 
-		if !(isym.Flags&SymSiggen != 0) {
+		if isym.Flags&SymSiggen == 0 {
 			isym.Flags |= SymSiggen
 			genwrapper(t, f, isym, 0)
 		}
@@ -649,7 +649,7 @@ var kinds = []int{
 
 func haspointers(t *Type) bool {
 	var t1 *Type
-	var ret int
+	var ret bool
 
 	if t.Haspointers != 0 {
 		return t.Haspointers-1 != 0
@@ -672,26 +672,26 @@ func haspointers(t *Type) bool {
 		TCOMPLEX64,
 		TCOMPLEX128,
 		TBOOL:
-		ret = 0
+		ret = false
 
 	case TARRAY:
 		if t.Bound < 0 { // slice
-			ret = 1
+			ret = true
 			break
 		}
 
 		if t.Bound == 0 { // empty array
-			ret = 0
+			ret = false
 			break
 		}
 
-		ret = bool2int(haspointers(t.Type))
+		ret = haspointers(t.Type)
 
 	case TSTRUCT:
-		ret = 0
+		ret = false
 		for t1 = t.Type; t1 != nil; t1 = t1.Down {
 			if haspointers(t1.Type) {
-				ret = 1
+				ret = true
 				break
 			}
 		}
@@ -706,11 +706,11 @@ func haspointers(t *Type) bool {
 		TFUNC:
 		fallthrough
 	default:
-		ret = 1
+		ret = true
 	}
 
-	t.Haspointers = uint8(1 + ret)
-	return ret != 0
+	t.Haspointers = 1 + uint8(bool2int(ret))
+	return ret
 }
 
 /*
@@ -724,7 +724,7 @@ func dcommontype(s *Sym, ot int, t *Type) int {
 	var i int
 	var alg int
 	var sizeofAlg int
-	var gcprog int
+	var gcprog bool
 	var sptr *Sym
 	var algsym *Sym
 	var zero *Sym
@@ -751,7 +751,7 @@ func dcommontype(s *Sym, ot int, t *Type) int {
 		algsym = dalgsym(t)
 	}
 
-	if t.Sym != nil && !(Isptr[t.Etype] != 0) {
+	if t.Sym != nil && Isptr[t.Etype] == 0 {
 		sptr = dtypesym(Ptrto(t))
 	} else {
 		sptr = weaktypesym(Ptrto(t))
@@ -811,10 +811,10 @@ func dcommontype(s *Sym, ot int, t *Type) int {
 	if !haspointers(t) {
 		i |= obj.KindNoPointers
 	}
-	if isdirectiface(t) != 0 {
+	if isdirectiface(t) {
 		i |= obj.KindDirectIface
 	}
-	if gcprog != 0 {
+	if gcprog {
 		i |= obj.KindGCProg
 	}
 	ot = duint8(s, ot, uint8(i)) // kind
@@ -825,7 +825,7 @@ func dcommontype(s *Sym, ot int, t *Type) int {
 	}
 
 	// gc
-	if gcprog != 0 {
+	if gcprog {
 		gengcprog(t, &gcprog0, &gcprog1)
 		if gcprog0 != nil {
 			ot = dsymptr(s, ot, gcprog0, 0)
@@ -937,7 +937,7 @@ func typenamesym(t *Type) *Sym {
 	var s *Sym
 	var n *Node
 
-	if t == nil || (Isptr[t.Etype] != 0 && t.Type == nil) || isideal(t) != 0 {
+	if t == nil || (Isptr[t.Etype] != 0 && t.Type == nil) || isideal(t) {
 		Fatal("typename %v", Tconv(t, 0))
 	}
 	s = typesym(t)
@@ -987,7 +987,7 @@ func weaktypesym(t *Type) *Sym {
  * Returns 1 if t has a reflexive equality operator.
  * That is, if x==x for all x of type t.
  */
-func isreflexive(t *Type) int {
+func isreflexive(t *Type) bool {
 	var t1 *Type
 	switch t.Etype {
 	case TBOOL,
@@ -1007,33 +1007,33 @@ func isreflexive(t *Type) int {
 		TUNSAFEPTR,
 		TSTRING,
 		TCHAN:
-		return 1
+		return true
 
 	case TFLOAT32,
 		TFLOAT64,
 		TCOMPLEX64,
 		TCOMPLEX128,
 		TINTER:
-		return 0
+		return false
 
 	case TARRAY:
-		if Isslice(t) != 0 {
+		if Isslice(t) {
 			Fatal("slice can't be a map key: %v", Tconv(t, 0))
 		}
 		return isreflexive(t.Type)
 
 	case TSTRUCT:
 		for t1 = t.Type; t1 != nil; t1 = t1.Down {
-			if !(isreflexive(t1.Type) != 0) {
-				return 0
+			if !isreflexive(t1.Type) {
+				return false
 			}
 		}
 
-		return 1
+		return true
 
 	default:
 		Fatal("bad type for map key: %v", Tconv(t, 0))
-		return 0
+		return false
 	}
 }
 
@@ -1062,7 +1062,7 @@ func dtypesym(t *Type) *Sym {
 		t = Types[t.Etype]
 	}
 
-	if isideal(t) != 0 {
+	if isideal(t) {
 		Fatal("dtypesym %v", Tconv(t, 0))
 	}
 
@@ -1090,7 +1090,7 @@ func dtypesym(t *Type) *Sym {
 	}
 
 	// named types from other files are defined only by those files
-	if tbase.Sym != nil && !(tbase.Local != 0) {
+	if tbase.Sym != nil && tbase.Local == 0 {
 		return s
 	}
 	if isforw[tbase.Etype] != 0 {
@@ -1230,7 +1230,7 @@ ok:
 		}
 
 		ot = duint16(s, ot, uint16(mapbucket(t).Width))
-		ot = duint8(s, ot, uint8(isreflexive(t.Down)))
+		ot = duint8(s, ot, uint8(bool2int(isreflexive(t.Down))))
 
 	case TPTR32,
 		TPTR64:
@@ -1265,7 +1265,7 @@ ok:
 		ot = duintxx(s, ot, uint64(n), Widthint)
 		for t1 = t.Type; t1 != nil; t1 = t1.Down {
 			// ../../runtime/type.go:/structField
-			if t1.Sym != nil && !(t1.Embedded != 0) {
+			if t1.Sym != nil && t1.Embedded == 0 {
 				ot = dgostringptr(s, ot, t1.Sym.Name)
 				if exportname(t1.Sym.Name) {
 					ot = dgostringptr(s, ot, "")
@@ -1447,12 +1447,12 @@ func dalgsym(t *Type) *Sym {
 	return s
 }
 
-func usegcprog(t *Type) int {
+func usegcprog(t *Type) bool {
 	var size int64
 	var nptr int64
 
 	if !haspointers(t) {
-		return 0
+		return false
 	}
 	if t.Width == BADWIDTH {
 		dowidth(t)
@@ -1473,7 +1473,7 @@ func usegcprog(t *Type) int {
 	// While large objects usually contain arrays; and even if it don't
 	// the program uses 2-bits per word while mask uses 4-bits per word,
 	// so the program is still smaller.
-	return bool2int(size > int64(2*Widthptr))
+	return size > int64(2*Widthptr)
 }
 
 // Generates sparse GC bitmask (4 bits per word).
@@ -1483,7 +1483,7 @@ func gengcmask(t *Type, gcmask []byte) {
 	var nptr int64
 	var i int64
 	var j int64
-	var half int
+	var half bool
 	var bits uint8
 	var pos []byte
 
@@ -1505,7 +1505,7 @@ func gengcmask(t *Type, gcmask []byte) {
 	pos = gcmask
 
 	nptr = (t.Width + int64(Widthptr) - 1) / int64(Widthptr)
-	half = 0
+	half = false
 
 	// If number of words is odd, repeat the mask.
 	// This makes simpler handling of arrays in runtime.
@@ -1520,12 +1520,12 @@ func gengcmask(t *Type, gcmask []byte) {
 				bits = obj.BitsScalar
 			}
 			bits <<= 2
-			if half != 0 {
+			if half {
 				bits <<= 4
 			}
 			pos[0] |= byte(bits)
-			half = bool2int(!(half != 0))
-			if !(half != 0) {
+			half = !half
+			if !half {
 				pos = pos[1:]
 			}
 		}
@@ -1699,7 +1699,7 @@ func gengcprog1(g *ProgGen, t *Type, xoffset *int64) {
 		*xoffset += t.Width
 
 	case TARRAY:
-		if Isslice(t) != 0 {
+		if Isslice(t) {
 			proggendata(g, obj.BitsPointer)
 			proggendata(g, obj.BitsScalar)
 			proggendata(g, obj.BitsScalar)

src/cmd/internal/gc/reg.go

@@ -74,7 +74,7 @@ func setaddrs(bit Bits) {
 	var v *Var
 	var node *Node
 
-	for bany(&bit) != 0 {
+	for bany(&bit) {
 		// convert each bit to a variable
 		i = bnum(bit)
 
@@ -169,9 +169,9 @@ func addmove(r *Flow, bn int, rn int, f int) {
 	p1.From.Type = obj.TYPE_REG
 	p1.From.Reg = int16(rn)
 	p1.From.Name = obj.NAME_NONE
-	if !(f != 0) {
+	if f == 0 {
 		p1.From = *a
-		*a = obj.Zprog.From
+		*a = obj.Addr{}
 		a.Type = obj.TYPE_REG
 		a.Reg = int16(rn)
 	}
@@ -182,18 +182,18 @@ func addmove(r *Flow, bn int, rn int, f int) {
 	Ostats.Nspill++
 }
 
-func overlap_reg(o1 int64, w1 int, o2 int64, w2 int) int {
+func overlap_reg(o1 int64, w1 int, o2 int64, w2 int) bool {
 	var t1 int64
 	var t2 int64
 
 	t1 = o1 + int64(w1)
 	t2 = o2 + int64(w2)
 
-	if !(t1 > o2 && t2 > o1) {
-		return 0
+	if t1 <= o2 || t2 <= o1 {
+		return false
 	}
 
-	return 1
+	return true
 }
 
 func mkvar(f *Flow, a *obj.Addr) Bits {
@@ -292,7 +292,7 @@ func mkvar(f *Flow, a *obj.Addr) Bits {
 				if int(v.etype) == et {
 					if int64(v.width) == w {
 						// TODO(rsc): Remove special case for arm here.
-						if !(flag != 0) || Thearch.Thechar != '5' {
+						if flag == 0 || Thearch.Thechar != '5' {
 							return blsh(uint(i))
 						}
 					}
@@ -300,7 +300,7 @@ func mkvar(f *Flow, a *obj.Addr) Bits {
 			}
 
 			// if they overlap, disable both
-			if overlap_reg(v.offset, v.width, o, int(w)) != 0 {
+			if overlap_reg(v.offset, v.width, o, int(w)) {
 				//				print("disable overlap %s %d %d %d %d, %E != %E\n", s->name, v->offset, v->width, o, w, v->etype, et);
 				v.addr = 1
 
@@ -446,7 +446,7 @@ func prop(f *Flow, ref Bits, cal Bits) {
 
 		switch f1.Prog.As {
 		case obj.ACALL:
-			if Noreturn(f1.Prog) != 0 {
+			if Noreturn(f1.Prog) {
 				break
 			}
 
@@ -499,7 +499,7 @@ func prop(f *Flow, ref Bits, cal Bits) {
 					// This will set the bits at most twice, keeping the overall loop linear.
 					v1, _ = v.node.Opt.(*Var)
 
-					if v == v1 || !(btest(&cal, uint(v1.id)) != 0) {
+					if v == v1 || !btest(&cal, uint(v1.id)) {
 						for ; v1 != nil; v1 = v1.nextinnode {
 							biset(&cal, uint(v1.id))
 						}
@@ -633,7 +633,7 @@ func paint1(f *Flow, bn int) {
 		return
 	}
 	for {
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.P1
@@ -641,7 +641,7 @@ func paint1(f *Flow, bn int) {
 			break
 		}
 		r1 = f1.Data.(*Reg)
-		if !(r1.refahead.b[z]&bb != 0) {
+		if r1.refahead.b[z]&bb == 0 {
 			break
 		}
 		if r1.act.b[z]&bb != 0 {
@@ -679,7 +679,7 @@ func paint1(f *Flow, bn int) {
 			}
 		}
 
-		if !(r.refahead.b[z]&bb != 0) {
+		if r.refahead.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.S2
@@ -696,7 +696,7 @@ func paint1(f *Flow, bn int) {
 		if r.act.b[z]&bb != 0 {
 			break
 		}
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 	}
@@ -714,11 +714,11 @@ func paint2(f *Flow, bn int, depth int) uint64 {
 	bb = 1 << uint(bn%64)
 	vreg = regbits
 	r = f.Data.(*Reg)
-	if !(r.act.b[z]&bb != 0) {
+	if r.act.b[z]&bb == 0 {
 		return vreg
 	}
 	for {
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.P1
@@ -726,10 +726,10 @@ func paint2(f *Flow, bn int, depth int) uint64 {
 			break
 		}
 		r1 = f1.Data.(*Reg)
-		if !(r1.refahead.b[z]&bb != 0) {
+		if r1.refahead.b[z]&bb == 0 {
 			break
 		}
-		if !(r1.act.b[z]&bb != 0) {
+		if r1.act.b[z]&bb == 0 {
 			break
 		}
 		f = f1
@@ -753,7 +753,7 @@ func paint2(f *Flow, bn int, depth int) uint64 {
 			}
 		}
 
-		if !(r.refahead.b[z]&bb != 0) {
+		if r.refahead.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.S2
@@ -767,10 +767,10 @@ func paint2(f *Flow, bn int, depth int) uint64 {
 			break
 		}
 		r = f.Data.(*Reg)
-		if !(r.act.b[z]&bb != 0) {
+		if r.act.b[z]&bb == 0 {
 			break
 		}
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 	}
@@ -793,7 +793,7 @@ func paint3(f *Flow, bn int, rb uint64, rn int) {
 		return
 	}
 	for {
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.P1
@@ -801,7 +801,7 @@ func paint3(f *Flow, bn int, rb uint64, rn int) {
 			break
 		}
 		r1 = f1.Data.(*Reg)
-		if !(r1.refahead.b[z]&bb != 0) {
+		if r1.refahead.b[z]&bb == 0 {
 			break
 		}
 		if r1.act.b[z]&bb != 0 {
@@ -851,7 +851,7 @@ func paint3(f *Flow, bn int, rb uint64, rn int) {
 			}
 		}
 
-		if !(r.refahead.b[z]&bb != 0) {
+		if r.refahead.b[z]&bb == 0 {
 			break
 		}
 		f1 = f.S2
@@ -868,7 +868,7 @@ func paint3(f *Flow, bn int, rb uint64, rn int) {
 		if r.act.b[z]&bb != 0 {
 			break
 		}
-		if !(r.refbehind.b[z]&bb != 0) {
+		if r.refbehind.b[z]&bb == 0 {
 			break
 		}
 	}
@@ -896,33 +896,33 @@ func dumpone(f *Flow, isreg int) {
 		for z = 0; z < BITS; z++ {
 			bit.b[z] = r.set.b[z] | r.use1.b[z] | r.use2.b[z] | r.refbehind.b[z] | r.refahead.b[z] | r.calbehind.b[z] | r.calahead.b[z] | r.regdiff.b[z] | r.act.b[z] | 0
 		}
-		if bany(&bit) != 0 {
+		if bany(&bit) {
 			fmt.Printf("\t")
-			if bany(&r.set) != 0 {
+			if bany(&r.set) {
 				fmt.Printf(" s:%v", Qconv(r.set, 0))
 			}
-			if bany(&r.use1) != 0 {
+			if bany(&r.use1) {
 				fmt.Printf(" u1:%v", Qconv(r.use1, 0))
 			}
-			if bany(&r.use2) != 0 {
+			if bany(&r.use2) {
 				fmt.Printf(" u2:%v", Qconv(r.use2, 0))
 			}
-			if bany(&r.refbehind) != 0 {
+			if bany(&r.refbehind) {
 				fmt.Printf(" rb:%v ", Qconv(r.refbehind, 0))
 			}
-			if bany(&r.refahead) != 0 {
+			if bany(&r.refahead) {
 				fmt.Printf(" ra:%v ", Qconv(r.refahead, 0))
 			}
-			if bany(&r.calbehind) != 0 {
+			if bany(&r.calbehind) {
 				fmt.Printf(" cb:%v ", Qconv(r.calbehind, 0))
 			}
-			if bany(&r.calahead) != 0 {
+			if bany(&r.calahead) {
 				fmt.Printf(" ca:%v ", Qconv(r.calahead, 0))
 			}
-			if bany(&r.regdiff) != 0 {
+			if bany(&r.regdiff) {
 				fmt.Printf(" d:%v ", Qconv(r.regdiff, 0))
 			}
-			if bany(&r.act) != 0 {
+			if bany(&r.act) {
 				fmt.Printf(" a:%v ", Qconv(r.act, 0))
 			}
 		}
@@ -1052,7 +1052,7 @@ func regopt(firstp *obj.Prog) {
 		r.set.b[0] |= info.Regset
 
 		bit = mkvar(f, &p.From)
-		if bany(&bit) != 0 {
+		if bany(&bit) {
 			if info.Flags&LeftAddr != 0 {
 				setaddrs(bit)
 			}
@@ -1080,7 +1080,7 @@ func regopt(firstp *obj.Prog) {
 		}
 
 		bit = mkvar(f, &p.To)
-		if bany(&bit) != 0 {
+		if bany(&bit) {
 			if info.Flags&RightAddr != 0 {
 				setaddrs(bit)
 			}
@@ -1143,7 +1143,7 @@ func regopt(firstp *obj.Prog) {
 
 	for f = firstf; f != nil; f = f.Link {
 		p = f.Prog
-		if p.As == obj.AVARDEF && Isfat(((p.To.Node).(*Node)).Type) != 0 && ((p.To.Node).(*Node)).Opt != nil {
+		if p.As == obj.AVARDEF && Isfat(((p.To.Node).(*Node)).Type) && ((p.To.Node).(*Node)).Opt != nil {
 			active++
 			walkvardef(p.To.Node.(*Node), f, active)
 		}
@@ -1172,7 +1172,7 @@ loop11:
 
 	for f = firstf; f != nil; f = f1 {
 		f1 = f.Link
-		if f1 != nil && f1.Active != 0 && !(f.Active != 0) {
+		if f1 != nil && f1.Active != 0 && f.Active == 0 {
 			prop(f, zbits, zbits)
 			i = 1
 		}
@@ -1244,7 +1244,7 @@ loop2:
 		for z = 0; z < BITS; z++ {
 			bit.b[z] = (r.refahead.b[z] | r.calahead.b[z]) &^ (externs.b[z] | params.b[z] | addrs.b[z] | consts.b[z])
 		}
-		if bany(&bit) != 0 && !(f.Refset != 0) {
+		if bany(&bit) && f.Refset == 0 {
 			// should never happen - all variables are preset
 			if Debug['w'] != 0 {
 				fmt.Printf("%v: used and not set: %v\n", f.Prog.Line(), Qconv(bit, 0))
@@ -1262,7 +1262,7 @@ loop2:
 		for z = 0; z < BITS; z++ {
 			bit.b[z] = r.set.b[z] &^ (r.refahead.b[z] | r.calahead.b[z] | addrs.b[z])
 		}
-		if bany(&bit) != 0 && !(f.Refset != 0) {
+		if bany(&bit) && f.Refset == 0 {
 			if Debug['w'] != 0 {
 				fmt.Printf("%v: set and not used: %v\n", f.Prog.Line(), Qconv(bit, 0))
 			}
@@ -1273,7 +1273,7 @@ loop2:
 		for z = 0; z < BITS; z++ {
 			bit.b[z] = LOAD(r, z) &^ (r.act.b[z] | addrs.b[z])
 		}
-		for bany(&bit) != 0 {
+		for bany(&bit) {
 			i = bnum(bit)
 			change = 0
 			paint1(f, i)
@@ -1354,7 +1354,7 @@ brk:
 	 * pass 7
 	 * peep-hole on basic block
 	 */
-	if !(Debug['R'] != 0) || Debug['P'] != 0 {
+	if Debug['R'] == 0 || Debug['P'] != 0 {
 		Thearch.Peep(firstp)
 	}
 

src/cmd/internal/gc/select.go

@@ -134,7 +134,6 @@ func walkselect(sel *Node) {
 			switch n.Op {
 			default:
 				Fatal("select %v", Oconv(int(n.Op), 0))
-				fallthrough
 
 				// ok already
 			case OSEND:
@@ -232,7 +231,6 @@ func walkselect(sel *Node) {
 		switch n.Op {
 		default:
 			Fatal("select %v", Oconv(int(n.Op), 0))
-			fallthrough
 
 			// if selectnbsend(c, v) { body } else { default body }
 		case OSEND:
@@ -299,7 +297,6 @@ func walkselect(sel *Node) {
 			switch n.Op {
 			default:
 				Fatal("select %v", Oconv(int(n.Op), 0))
-				fallthrough
 
 				// selectsend(sel *byte, hchan *chan any, elem *any) (selected bool);
 			case OSEND:

src/cmd/internal/gc/swt.go

@@ -281,7 +281,7 @@ func casebody(sw *Node, typeswvar *Node) {
 	var go_ *Node
 	var br *Node
 	var lno int32
-	var needvar int32
+	var needvar bool
 
 	if sw.List == nil {
 		return
@@ -301,7 +301,7 @@ func casebody(sw *Node, typeswvar *Node) {
 			Fatal("casebody %v", Oconv(int(n.Op), 0))
 		}
 		n.Op = OCASE
-		needvar = int32(bool2int(count(n.List) != 1 || n.List.N.Op == OLITERAL))
+		needvar = count(n.List) != 1 || n.List.N.Op == OLITERAL
 
 		go_ = Nod(OGOTO, newlabel_swt(), nil)
 		if n.List == nil {
@@ -332,7 +332,7 @@ func casebody(sw *Node, typeswvar *Node) {
 		}
 
 		stat = list(stat, Nod(OLABEL, go_.Left, nil))
-		if typeswvar != nil && needvar != 0 && n.Nname != nil {
+		if typeswvar != nil && needvar && n.Nname != nil {
 			var l *NodeList
 
 			l = list1(Nod(ODCL, n.Nname, nil))
@@ -410,7 +410,7 @@ func mkcaselist(sw *Node, arg int) *Case {
 				continue
 			}
 
-			if Istype(n.Left.Type, TINTER) != 0 {
+			if Istype(n.Left.Type, TINTER) {
 				c.type_ = Ttypevar
 				continue
 			}
@@ -552,7 +552,7 @@ func exprswitch(sw *Node) {
 	casebody(sw, nil)
 
 	arg = Snorm
-	if Isconst(sw.Ntest, CTBOOL) != 0 {
+	if Isconst(sw.Ntest, CTBOOL) {
 		arg = Strue
 		if sw.Ntest.Val.U.Bval == 0 {
 			arg = Sfalse
@@ -572,7 +572,7 @@ func exprswitch(sw *Node) {
 
 	cas = nil
 	if arg == Strue || arg == Sfalse {
-		exprname = Nodbool(bool2int(arg == Strue))
+		exprname = Nodbool(arg == Strue)
 	} else if consttype(sw.Ntest) >= 0 {
 		// leave constants to enable dead code elimination (issue 9608)
 		exprname = sw.Ntest
@@ -600,7 +600,7 @@ loop:
 	}
 
 	// deal with the variables one-at-a-time
-	if !(okforcmp[t.Etype] != 0) || c0.type_ != Texprconst {
+	if okforcmp[t.Etype] == 0 || c0.type_ != Texprconst {
 		a = exprbsw(c0, 1, arg)
 		cas = list(cas, a)
 		c0 = c0.link
@@ -738,7 +738,7 @@ func typeswitch(sw *Node) {
 	}
 
 	walkexpr(&sw.Ntest.Right, &sw.Ninit)
-	if !(Istype(sw.Ntest.Right.Type, TINTER) != 0) {
+	if !Istype(sw.Ntest.Right.Type, TINTER) {
 		Yyerror("type switch must be on an interface")
 		return
 	}
@@ -764,7 +764,7 @@ func typeswitch(sw *Node) {
 	typecheck(&hashname, Erv)
 
 	t = sw.Ntest.Right.Type
-	if isnilinter(t) != 0 {
+	if isnilinter(t) {
 		a = syslook("efacethash", 1)
 	} else {
 		a = syslook("ifacethash", 1)
@@ -871,7 +871,7 @@ func walkswitch(sw *Node) {
 	 * both have inserted OBREAK statements
 	 */
 	if sw.Ntest == nil {
-		sw.Ntest = Nodbool(1)
+		sw.Ntest = Nodbool(true)
 		typecheck(&sw.Ntest, Erv)
 	}
 
@@ -933,11 +933,11 @@ func typecheckswitch(n *Node) {
 			t = Types[TBOOL]
 		}
 		if t != nil {
-			if !(okforeq[t.Etype] != 0) {
+			if okforeq[t.Etype] == 0 {
 				Yyerror("cannot switch on %v", Nconv(n.Ntest, obj.FmtLong))
-			} else if t.Etype == TARRAY && !(Isfixedarray(t) != 0) {
+			} else if t.Etype == TARRAY && !Isfixedarray(t) {
 				nilonly = "slice"
-			} else if t.Etype == TARRAY && Isfixedarray(t) != 0 && algtype1(t, nil) == ANOEQ {
+			} else if t.Etype == TARRAY && Isfixedarray(t) && algtype1(t, nil) == ANOEQ {
 				Yyerror("cannot switch on %v", Nconv(n.Ntest, obj.FmtLong))
 			} else if t.Etype == TSTRUCT && algtype1(t, &badtype) == ANOEQ {
 				Yyerror("cannot switch on %v (struct containing %v cannot be compared)", Nconv(n.Ntest, obj.FmtLong), Tconv(badtype, 0))
@@ -976,27 +976,27 @@ func typecheckswitch(n *Node) {
 
 					if ll.N.Op == OTYPE {
 						Yyerror("type %v is not an expression", Tconv(ll.N.Type, 0))
-					} else if ll.N.Type != nil && !(assignop(ll.N.Type, t, nil) != 0) && !(assignop(t, ll.N.Type, nil) != 0) {
+					} else if 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)", Nconv(ll.N, 0), Nconv(n.Ntest, 0), Tconv(ll.N.Type, 0), Tconv(t, 0))
 						} else {
 							Yyerror("invalid case %v in switch (mismatched types %v and bool)", Nconv(ll.N, 0), Tconv(ll.N.Type, 0))
 						}
-					} else if nilonly != "" && !(Isconst(ll.N, CTNIL) != 0) {
+					} else if nilonly != "" && !Isconst(ll.N, CTNIL) {
 						Yyerror("invalid case %v in switch (can only compare %s %v to nil)", Nconv(ll.N, 0), nilonly, Nconv(n.Ntest, 0))
 					}
 
 				case Etype: // type switch
-					if ll.N.Op == OLITERAL && Istype(ll.N.Type, TNIL) != 0 {
+					if ll.N.Op == OLITERAL && Istype(ll.N.Type, TNIL) {
 					} else if 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
-					} else if ll.N.Type.Etype != TINTER && t.Etype == TINTER && !(implements(ll.N.Type, t, &missing, &have, &ptr) != 0) {
-						if have != nil && !(missing.Broke != 0) && !(have.Broke != 0) {
+					} else if 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), Tconv(ll.N.Type, 0), Sconv(missing.Sym, 0), Sconv(have.Sym, 0), Tconv(have.Type, obj.FmtShort), Sconv(missing.Sym, 0), Tconv(missing.Type, obj.FmtShort))
-						} else if !(missing.Broke != 0) {
+						} 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), Tconv(ll.N.Type, 0), Sconv(missing.Sym, 0))
 						}
 					}
@@ -1008,7 +1008,7 @@ func typecheckswitch(n *Node) {
 			ll = ncase.List
 			nvar = ncase.Nname
 			if nvar != nil {
-				if ll != nil && ll.Next == nil && ll.N.Type != nil && !(Istype(ll.N.Type, TNIL) != 0) {
+				if ll != nil && ll.Next == nil && ll.N.Type != nil && !Istype(ll.N.Type, TNIL) {
 					// single entry type switch
 					nvar.Ntype = typenod(ll.N.Type)
 				} else {

src/cmd/internal/gc/unsafe.go

@@ -161,18 +161,18 @@ ret:
 	return n
 }
 
-func isunsafebuiltin(n *Node) int {
+func isunsafebuiltin(n *Node) bool {
 	if n == nil || n.Op != ONAME || n.Sym == nil || n.Sym.Pkg != unsafepkg {
-		return 0
+		return false
 	}
 	if n.Sym.Name == "Sizeof" {
-		return 1
+		return true
 	}
 	if n.Sym.Name == "Offsetof" {
-		return 1
+		return true
 	}
 	if n.Sym.Name == "Alignof" {
-		return 1
+		return true
 	}
-	return 0
+	return false
 }

src/cmd/internal/gc/y.go

@@ -851,6 +851,7 @@ type yyLexer interface {
 }
 
 type yyParser interface {
+	Parse(yyLexer) int
 	Lookahead() int
 }
 
@@ -862,6 +863,13 @@ func (p *yyParserImpl) Lookahead() int {
 	return p.lookahead()
 }
 
+func yyNewParser() yyParser {
+	p := &yyParserImpl{
+		lookahead: func() int { return -1 },
+	}
+	return p
+}
+
 const yyFlag = -1000
 
 func yyTokname(c int) string {
@@ -919,6 +927,10 @@ out:
 }
 
 func yyParse(yylex yyLexer) int {
+	return yyNewParser().Parse(yylex)
+}
+
+func (yyrcvr *yyParserImpl) Parse(yylex yyLexer) int {
 	var yyn int
 	var yylval yySymType
 	var yyVAL yySymType
@@ -930,19 +942,12 @@ func yyParse(yylex yyLexer) int {
 	yystate := 0
 	yychar := -1
 	yytoken := -1 // yychar translated into internal numbering
-	if lx, ok := yylex.(interface {
-		SetParser(yyParser)
-	}); ok {
-		p := &yyParserImpl{
-			lookahead: func() int { return yychar },
-		}
-		lx.SetParser(p)
+	yyrcvr.lookahead = func() int { return yychar }
 	defer func() {
 		// Make sure we report no lookahead when not parsing.
 		yychar = -1
 		yytoken = -1
 	}()
-	}
 	yyp := -1
 	goto yystack