diff --git a/src/cmd/compile/internal/amd64/gsubr.go b/src/cmd/compile/internal/amd64/gsubr.go
index b2fa113..d305076 100644
--- a/src/cmd/compile/internal/amd64/gsubr.go
+++ b/src/cmd/compile/internal/amd64/gsubr.go
@@ -722,7 +722,7 @@
 	a := obj.AXXX
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry %v-%v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("optoas: no entry %v-%v", gc.Oconv(op, 0), t)
 
 	case OADDR_ | gc.TPTR32:
 		a = x86.ALEAL
@@ -1264,7 +1264,7 @@
 	case x86.AJPS:
 		return x86.ASETPS
 	}
-	gc.Fatalf("jmptoset: no entry for %v", gc.Oconv(jmp, 0))
+	gc.Fatalf("jmptoset: no entry for %v", jmp)
 	panic("unreachable")
 }
 
diff --git a/src/cmd/compile/internal/arm/cgen64.go b/src/cmd/compile/internal/arm/cgen64.go
index 9cda561..b9bd53e 100644
--- a/src/cmd/compile/internal/arm/cgen64.go
+++ b/src/cmd/compile/internal/arm/cgen64.go
@@ -19,7 +19,7 @@
 	if res.Op != gc.OINDREG && res.Op != gc.ONAME {
 		gc.Dump("n", n)
 		gc.Dump("res", res)
-		gc.Fatalf("cgen64 %v of %v", gc.Oconv(int(n.Op), 0), gc.Oconv(int(res.Op), 0))
+		gc.Fatalf("cgen64 %v of %v", gc.Oconv(n.Op, 0), gc.Oconv(res.Op, 0))
 	}
 
 	l := n.Left
@@ -35,7 +35,7 @@
 	split64(l, &lo1, &hi1)
 	switch n.Op {
 	default:
-		gc.Fatalf("cgen64 %v", gc.Oconv(int(n.Op), 0))
+		gc.Fatalf("cgen64 %v", gc.Oconv(n.Op, 0))
 
 	case gc.OMINUS:
 		var lo2 gc.Node
@@ -793,7 +793,7 @@
 	var br *obj.Prog
 	switch op {
 	default:
-		gc.Fatalf("cmp64 %v %v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("cmp64 %v %v", gc.Oconv(op, 0), t)
 
 		// cmp hi
 	// bne L
diff --git a/src/cmd/compile/internal/arm/gsubr.go b/src/cmd/compile/internal/arm/gsubr.go
index 108d78a..97ca0cd 100644
--- a/src/cmd/compile/internal/arm/gsubr.go
+++ b/src/cmd/compile/internal/arm/gsubr.go
@@ -719,7 +719,7 @@
 	gc.Naddr(&a, n)
 	if a.Type != obj.TYPE_REG {
 		if n != nil {
-			gc.Fatalf("bad in raddr: %v", gc.Oconv(int(n.Op), 0))
+			gc.Fatalf("bad in raddr: %v", gc.Oconv(n.Op, 0))
 		} else {
 			gc.Fatalf("bad in raddr: <null>")
 		}
@@ -790,7 +790,7 @@
 	a := obj.AXXX
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry %v-%v etype %v simtype %v", gc.Oconv(int(op), 0), t, gc.Types[t.Etype], gc.Types[gc.Simtype[t.Etype]])
+		gc.Fatalf("optoas: no entry %v-%v etype %v simtype %v", gc.Oconv(op, 0), t, gc.Types[t.Etype], gc.Types[gc.Simtype[t.Etype]])
 
 		/*	case CASE(OADDR, TPTR32):
 				a = ALEAL;
diff --git a/src/cmd/compile/internal/arm64/gsubr.go b/src/cmd/compile/internal/arm64/gsubr.go
index 97f73f5..86d6530 100644
--- a/src/cmd/compile/internal/arm64/gsubr.go
+++ b/src/cmd/compile/internal/arm64/gsubr.go
@@ -567,7 +567,7 @@
 	gc.Naddr(&a, n)
 	if a.Type != obj.TYPE_REG {
 		if n != nil {
-			gc.Fatalf("bad in raddr: %v", gc.Oconv(int(n.Op), 0))
+			gc.Fatalf("bad in raddr: %v", gc.Oconv(n.Op, 0))
 		} else {
 			gc.Fatalf("bad in raddr: <null>")
 		}
@@ -579,7 +579,7 @@
 
 func gcmp(as int, lhs *gc.Node, rhs *gc.Node) *obj.Prog {
 	if lhs.Op != gc.OREGISTER {
-		gc.Fatalf("bad operands to gcmp: %v %v", gc.Oconv(int(lhs.Op), 0), gc.Oconv(int(rhs.Op), 0))
+		gc.Fatalf("bad operands to gcmp: %v %v", gc.Oconv(lhs.Op, 0), gc.Oconv(rhs.Op, 0))
 	}
 
 	p := rawgins(as, rhs, nil)
@@ -622,7 +622,7 @@
 	a := int(obj.AXXX)
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(op, 0), t)
 
 	case OEQ_ | gc.TBOOL,
 		OEQ_ | gc.TINT8,
diff --git a/src/cmd/compile/internal/gc/bexport.go b/src/cmd/compile/internal/gc/bexport.go
index 4cbcadb..830b3be 100644
--- a/src/cmd/compile/internal/gc/bexport.go
+++ b/src/cmd/compile/internal/gc/bexport.go
@@ -221,7 +221,7 @@
 				types = append(types, t)
 
 			default:
-				Fatalf("exporter: unexpected export symbol: %v %v", Oconv(int(n.Op), 0), sym)
+				Fatalf("exporter: unexpected export symbol: %v %v", Oconv(n.Op, 0), sym)
 			}
 		}
 	}
diff --git a/src/cmd/compile/internal/gc/cgen.go b/src/cmd/compile/internal/gc/cgen.go
index 43bb4c1..389764c 100644
--- a/src/cmd/compile/internal/gc/cgen.go
+++ b/src/cmd/compile/internal/gc/cgen.go
@@ -1792,7 +1792,7 @@
 	}
 
 	if n.Type.Etype != TBOOL {
-		Fatalf("bgen: bad type %v for %v", n.Type, Oconv(int(n.Op), 0))
+		Fatalf("bgen: bad type %v for %v", n.Type, Oconv(n.Op, 0))
 	}
 
 	for n.Op == OCONVNOP {
@@ -2439,12 +2439,12 @@
 func cgen_callinter(n *Node, res *Node, proc int) {
 	i := n.Left
 	if i.Op != ODOTINTER {
-		Fatalf("cgen_callinter: not ODOTINTER %v", Oconv(int(i.Op), 0))
+		Fatalf("cgen_callinter: not ODOTINTER %v", Oconv(i.Op, 0))
 	}
 
 	f := i.Right // field
 	if f.Op != ONAME {
-		Fatalf("cgen_callinter: not ONAME %v", Oconv(int(f.Op), 0))
+		Fatalf("cgen_callinter: not ONAME %v", Oconv(f.Op, 0))
 	}
 
 	i = i.Left // interface
diff --git a/src/cmd/compile/internal/gc/const.go b/src/cmd/compile/internal/gc/const.go
index b825fa7..7cd25c7 100644
--- a/src/cmd/compile/internal/gc/const.go
+++ b/src/cmd/compile/internal/gc/const.go
@@ -648,7 +648,7 @@
 		switch uint32(n.Op)<<16 | uint32(v.Ctype()) {
 		default:
 			if n.Diag == 0 {
-				Yyerror("illegal constant expression %v %v", Oconv(int(n.Op), 0), nl.Type)
+				Yyerror("illegal constant expression %v %v", Oconv(n.Op, 0), nl.Type)
 				n.Diag = 1
 			}
 			return
@@ -1135,7 +1135,7 @@
 
 illegal:
 	if n.Diag == 0 {
-		Yyerror("illegal constant expression: %v %v %v", nl.Type, Oconv(int(n.Op), 0), nr.Type)
+		Yyerror("illegal constant expression: %v %v %v", nl.Type, Oconv(n.Op, 0), nr.Type)
 		n.Diag = 1
 	}
 }
diff --git a/src/cmd/compile/internal/gc/cplx.go b/src/cmd/compile/internal/gc/cplx.go
index b692456..4d89fb7 100644
--- a/src/cmd/compile/internal/gc/cplx.go
+++ b/src/cmd/compile/internal/gc/cplx.go
@@ -398,7 +398,7 @@
 	switch n.Op {
 	default:
 		Dump("complexgen: unknown op", n)
-		Fatalf("complexgen: unknown op %v", Oconv(int(n.Op), 0))
+		Fatalf("complexgen: unknown op %v", Oconv(n.Op, 0))
 
 	case ODOT,
 		ODOTPTR,
@@ -457,7 +457,7 @@
 
 	switch n.Op {
 	default:
-		Fatalf("complexgen: unknown op %v", Oconv(int(n.Op), 0))
+		Fatalf("complexgen: unknown op %v", Oconv(n.Op, 0))
 
 	case OCONV:
 		Complexmove(nl, res)
diff --git a/src/cmd/compile/internal/gc/dcl.go b/src/cmd/compile/internal/gc/dcl.go
index 94c4beb..5681ece 100644
--- a/src/cmd/compile/internal/gc/dcl.go
+++ b/src/cmd/compile/internal/gc/dcl.go
@@ -564,7 +564,7 @@
 
 func funcargs(nt *Node) {
 	if nt.Op != OTFUNC {
-		Fatalf("funcargs %v", Oconv(int(nt.Op), 0))
+		Fatalf("funcargs %v", Oconv(nt.Op, 0))
 	}
 
 	// re-start the variable generation number
@@ -578,7 +578,7 @@
 	if nt.Left != nil {
 		n := nt.Left
 		if n.Op != ODCLFIELD {
-			Fatalf("funcargs receiver %v", Oconv(int(n.Op), 0))
+			Fatalf("funcargs receiver %v", Oconv(n.Op, 0))
 		}
 		if n.Left != nil {
 			n.Left.Op = ONAME
@@ -595,7 +595,7 @@
 	for it := nodeSeqIterate(nt.List); !it.Done(); it.Next() {
 		n = it.N()
 		if n.Op != ODCLFIELD {
-			Fatalf("funcargs in %v", Oconv(int(n.Op), 0))
+			Fatalf("funcargs in %v", Oconv(n.Op, 0))
 		}
 		if n.Left != nil {
 			n.Left.Op = ONAME
@@ -616,7 +616,7 @@
 		n = it.N()
 
 		if n.Op != ODCLFIELD {
-			Fatalf("funcargs out %v", Oconv(int(n.Op), 0))
+			Fatalf("funcargs out %v", Oconv(n.Op, 0))
 		}
 
 		if n.Left == nil {
diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index b6e47e7..7054249 100644
--- a/src/cmd/compile/internal/gc/esc.go
+++ b/src/cmd/compile/internal/gc/esc.go
@@ -943,8 +943,8 @@
 	if Debug['m'] > 1 {
 		fmt.Printf("%v:[%d] %v escassign: %v(%v)[%v] = %v(%v)[%v]\n",
 			linestr(lineno), e.loopdepth, funcSym(Curfn),
-			Nconv(dst, obj.FmtShort), Jconv(dst, obj.FmtShort), Oconv(int(dst.Op), 0),
-			Nconv(src, obj.FmtShort), Jconv(src, obj.FmtShort), Oconv(int(src.Op), 0))
+			Nconv(dst, obj.FmtShort), Jconv(dst, obj.FmtShort), Oconv(dst.Op, 0),
+			Nconv(src, obj.FmtShort), Jconv(src, obj.FmtShort), Oconv(src.Op, 0))
 	}
 
 	setlineno(dst)
@@ -1639,7 +1639,7 @@
 
 	if Debug['m'] > 1 {
 		fmt.Printf("escwalk: level:%d depth:%d %.*s op=%v %v(%v) scope:%v[%d] extraloopdepth=%v\n",
-			level, e.pdepth, e.pdepth, "\t\t\t\t\t\t\t\t\t\t", Oconv(int(src.Op), 0), Nconv(src, obj.FmtShort), Jconv(src, obj.FmtShort), e.curfnSym(src), srcE.Escloopdepth, extraloopdepth)
+			level, e.pdepth, e.pdepth, "\t\t\t\t\t\t\t\t\t\t", Oconv(src.Op, 0), Nconv(src, obj.FmtShort), Jconv(src, obj.FmtShort), e.curfnSym(src), srcE.Escloopdepth, extraloopdepth)
 	}
 
 	e.pdepth++
diff --git a/src/cmd/compile/internal/gc/export.go b/src/cmd/compile/internal/gc/export.go
index b20f826..b62c13e 100644
--- a/src/cmd/compile/internal/gc/export.go
+++ b/src/cmd/compile/internal/gc/export.go
@@ -338,7 +338,7 @@
 
 	switch s.Def.Op {
 	default:
-		Yyerror("unexpected export symbol: %v %v", Oconv(int(s.Def.Op), 0), s)
+		Yyerror("unexpected export symbol: %v %v", Oconv(s.Def.Op, 0), s)
 
 	case OLITERAL:
 		dumpexportconst(s)
diff --git a/src/cmd/compile/internal/gc/fmt.go b/src/cmd/compile/internal/gc/fmt.go
index ef27195..fb18a39 100644
--- a/src/cmd/compile/internal/gc/fmt.go
+++ b/src/cmd/compile/internal/gc/fmt.go
@@ -174,14 +174,14 @@
 }
 
 // Fmt "%O":  Node opcodes
-func Oconv(o int, flag int) string {
+func Oconv(o Op, flag int) string {
 	if (flag&obj.FmtSharp != 0) || fmtmode != FDbg {
-		if o >= 0 && o < len(goopnames) && goopnames[o] != "" {
+		if o >= 0 && int(o) < len(goopnames) && goopnames[o] != "" {
 			return goopnames[o]
 		}
 	}
 
-	if o >= 0 && o < len(opnames) && opnames[o] != "" {
+	if o >= 0 && int(o) < len(opnames) && opnames[o] != "" {
 		return opnames[o]
 	}
 
@@ -859,7 +859,7 @@
 			break
 		}
 
-		f += fmt.Sprintf("%v %v= %v", n.Left, Oconv(int(n.Etype), obj.FmtSharp), n.Right)
+		f += fmt.Sprintf("%v %v= %v", n.Left, Oconv(Op(n.Etype), obj.FmtSharp), n.Right)
 
 	case OAS2:
 		if n.Colas && !complexinit {
@@ -933,11 +933,11 @@
 
 	case OSELECT, OSWITCH:
 		if fmtmode == FErr {
-			f += fmt.Sprintf("%v statement", Oconv(int(n.Op), 0))
+			f += fmt.Sprintf("%v statement", Oconv(n.Op, 0))
 			break
 		}
 
-		f += Oconv(int(n.Op), obj.FmtSharp)
+		f += Oconv(n.Op, obj.FmtSharp)
 		if simpleinit {
 			f += fmt.Sprintf(" %v;", nodeSeqFirst(n.Ninit))
 		}
@@ -960,9 +960,9 @@
 		OFALL,
 		OXFALL:
 		if n.Left != nil {
-			f += fmt.Sprintf("%v %v", Oconv(int(n.Op), obj.FmtSharp), n.Left)
+			f += fmt.Sprintf("%v %v", Oconv(n.Op, obj.FmtSharp), n.Left)
 		} else {
-			f += Oconv(int(n.Op), obj.FmtSharp)
+			f += Oconv(n.Op, obj.FmtSharp)
 		}
 
 	case OEMPTY:
@@ -1341,7 +1341,7 @@
 		return f
 
 	case OCOPY, OCOMPLEX:
-		return fmt.Sprintf("%v(%v, %v)", Oconv(int(n.Op), obj.FmtSharp), n.Left, n.Right)
+		return fmt.Sprintf("%v(%v, %v)", Oconv(n.Op, obj.FmtSharp), n.Left, n.Right)
 
 	case OCONV,
 		OCONVIFACE,
@@ -1373,12 +1373,12 @@
 		OPRINT,
 		OPRINTN:
 		if n.Left != nil {
-			return fmt.Sprintf("%v(%v)", Oconv(int(n.Op), obj.FmtSharp), n.Left)
+			return fmt.Sprintf("%v(%v)", Oconv(n.Op, obj.FmtSharp), n.Left)
 		}
 		if n.Isddd {
-			return fmt.Sprintf("%v(%v...)", Oconv(int(n.Op), obj.FmtSharp), Hconv(n.List, obj.FmtComma))
+			return fmt.Sprintf("%v(%v...)", Oconv(n.Op, obj.FmtSharp), Hconv(n.List, obj.FmtComma))
 		}
-		return fmt.Sprintf("%v(%v)", Oconv(int(n.Op), obj.FmtSharp), Hconv(n.List, obj.FmtComma))
+		return fmt.Sprintf("%v(%v)", Oconv(n.Op, obj.FmtSharp), Hconv(n.List, obj.FmtComma))
 
 	case OCALL, OCALLFUNC, OCALLINTER, OCALLMETH, OGETG:
 		var f string
@@ -1412,9 +1412,9 @@
 		ORECV:
 		var f string
 		if n.Left.Op == n.Op {
-			f += fmt.Sprintf("%v ", Oconv(int(n.Op), obj.FmtSharp))
+			f += fmt.Sprintf("%v ", Oconv(n.Op, obj.FmtSharp))
 		} else {
-			f += Oconv(int(n.Op), obj.FmtSharp)
+			f += Oconv(n.Op, obj.FmtSharp)
 		}
 		f += exprfmt(n.Left, nprec+1)
 		return f
@@ -1443,7 +1443,7 @@
 		var f string
 		f += exprfmt(n.Left, nprec)
 
-		f += fmt.Sprintf(" %v ", Oconv(int(n.Op), obj.FmtSharp))
+		f += fmt.Sprintf(" %v ", Oconv(n.Op, obj.FmtSharp))
 		f += exprfmt(n.Right, nprec+1)
 		return f
 
@@ -1464,12 +1464,12 @@
 		var f string
 		f += exprfmt(n.Left, nprec)
 		// TODO(marvin): Fix Node.EType type union.
-		f += fmt.Sprintf(" %v ", Oconv(int(n.Etype), obj.FmtSharp))
+		f += fmt.Sprintf(" %v ", Oconv(Op(n.Etype), obj.FmtSharp))
 		f += exprfmt(n.Right, nprec+1)
 		return f
 	}
 
-	return fmt.Sprintf("<node %v>", Oconv(int(n.Op), 0))
+	return fmt.Sprintf("<node %v>", Oconv(n.Op, 0))
 }
 
 func nodefmt(n *Node, flag int) string {
@@ -1524,40 +1524,40 @@
 		}
 
 		if nodeSeqLen(n.Ninit) != 0 {
-			fmt.Fprintf(&buf, "%v-init%v", Oconv(int(n.Op), 0), n.Ninit)
+			fmt.Fprintf(&buf, "%v-init%v", Oconv(n.Op, 0), n.Ninit)
 			indent(&buf)
 		}
 	}
 
 	switch n.Op {
 	default:
-		fmt.Fprintf(&buf, "%v%v", Oconv(int(n.Op), 0), Jconv(n, 0))
+		fmt.Fprintf(&buf, "%v%v", Oconv(n.Op, 0), Jconv(n, 0))
 
 	case OREGISTER, OINDREG:
-		fmt.Fprintf(&buf, "%v-%v%v", Oconv(int(n.Op), 0), obj.Rconv(int(n.Reg)), Jconv(n, 0))
+		fmt.Fprintf(&buf, "%v-%v%v", Oconv(n.Op, 0), obj.Rconv(int(n.Reg)), Jconv(n, 0))
 
 	case OLITERAL:
-		fmt.Fprintf(&buf, "%v-%v%v", Oconv(int(n.Op), 0), Vconv(n.Val(), 0), Jconv(n, 0))
+		fmt.Fprintf(&buf, "%v-%v%v", Oconv(n.Op, 0), Vconv(n.Val(), 0), Jconv(n, 0))
 
 	case ONAME, ONONAME:
 		if n.Sym != nil {
-			fmt.Fprintf(&buf, "%v-%v%v", Oconv(int(n.Op), 0), n.Sym, Jconv(n, 0))
+			fmt.Fprintf(&buf, "%v-%v%v", Oconv(n.Op, 0), n.Sym, Jconv(n, 0))
 		} else {
-			fmt.Fprintf(&buf, "%v%v", Oconv(int(n.Op), 0), Jconv(n, 0))
+			fmt.Fprintf(&buf, "%v%v", Oconv(n.Op, 0), Jconv(n, 0))
 		}
 		if recur && n.Type == nil && n.Name != nil && n.Name.Param != nil && n.Name.Param.Ntype != nil {
 			indent(&buf)
-			fmt.Fprintf(&buf, "%v-ntype%v", Oconv(int(n.Op), 0), n.Name.Param.Ntype)
+			fmt.Fprintf(&buf, "%v-ntype%v", Oconv(n.Op, 0), n.Name.Param.Ntype)
 		}
 
 	case OASOP:
-		fmt.Fprintf(&buf, "%v-%v%v", Oconv(int(n.Op), 0), Oconv(int(n.Etype), 0), Jconv(n, 0))
+		fmt.Fprintf(&buf, "%v-%v%v", Oconv(n.Op, 0), Oconv(Op(n.Etype), 0), Jconv(n, 0))
 
 	case OTYPE:
-		fmt.Fprintf(&buf, "%v %v%v type=%v", Oconv(int(n.Op), 0), n.Sym, Jconv(n, 0), n.Type)
+		fmt.Fprintf(&buf, "%v %v%v type=%v", Oconv(n.Op, 0), n.Sym, Jconv(n, 0), n.Type)
 		if recur && n.Type == nil && n.Name.Param.Ntype != nil {
 			indent(&buf)
-			fmt.Fprintf(&buf, "%v-ntype%v", Oconv(int(n.Op), 0), n.Name.Param.Ntype)
+			fmt.Fprintf(&buf, "%v-ntype%v", Oconv(n.Op, 0), n.Name.Param.Ntype)
 		}
 	}
 
@@ -1578,17 +1578,17 @@
 		}
 		if nodeSeqLen(n.List) != 0 {
 			indent(&buf)
-			fmt.Fprintf(&buf, "%v-list%v", Oconv(int(n.Op), 0), n.List)
+			fmt.Fprintf(&buf, "%v-list%v", Oconv(n.Op, 0), n.List)
 		}
 
 		if nodeSeqLen(n.Rlist) != 0 {
 			indent(&buf)
-			fmt.Fprintf(&buf, "%v-rlist%v", Oconv(int(n.Op), 0), n.Rlist)
+			fmt.Fprintf(&buf, "%v-rlist%v", Oconv(n.Op, 0), n.Rlist)
 		}
 
 		if len(n.Nbody.Slice()) != 0 {
 			indent(&buf)
-			fmt.Fprintf(&buf, "%v-body%v", Oconv(int(n.Op), 0), n.Nbody)
+			fmt.Fprintf(&buf, "%v-body%v", Oconv(n.Op, 0), n.Nbody)
 		}
 	}
 
diff --git a/src/cmd/compile/internal/gc/gen.go b/src/cmd/compile/internal/gc/gen.go
index d021749..0b69f73 100644
--- a/src/cmd/compile/internal/gc/gen.go
+++ b/src/cmd/compile/internal/gc/gen.go
@@ -225,7 +225,7 @@
 func cgen_proc(n *Node, proc int) {
 	switch n.Left.Op {
 	default:
-		Fatalf("cgen_proc: unknown call %v", Oconv(int(n.Left.Op), 0))
+		Fatalf("cgen_proc: unknown call %v", Oconv(n.Left.Op, 0))
 
 	case OCALLMETH:
 		cgen_callmeth(n.Left, proc)
diff --git a/src/cmd/compile/internal/gc/gsubr.go b/src/cmd/compile/internal/gc/gsubr.go
index 73f71dd..c533bd1 100644
--- a/src/cmd/compile/internal/gc/gsubr.go
+++ b/src/cmd/compile/internal/gc/gsubr.go
@@ -322,7 +322,7 @@
 		a := a // copy to let escape into Ctxt.Dconv
 		Debug['h'] = 1
 		Dump("naddr", n)
-		Fatalf("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))
+		Fatalf("naddr: bad %v %v", Oconv(n.Op, 0), Ctxt.Dconv(a))
 
 	case OREGISTER:
 		a.Type = obj.TYPE_REG
@@ -423,7 +423,7 @@
 		if n.Left.Type.Etype != TSTRUCT || n.Left.Type.Type.Sym != n.Right.Sym {
 			Debug['h'] = 1
 			Dump("naddr", n)
-			Fatalf("naddr: bad %v %v", Oconv(int(n.Op), 0), Ctxt.Dconv(a))
+			Fatalf("naddr: bad %v %v", Oconv(n.Op, 0), Ctxt.Dconv(a))
 		}
 		Naddr(a, n.Left)
 
@@ -466,7 +466,7 @@
 		}
 		if a.Type != obj.TYPE_MEM {
 			a := a // copy to let escape into Ctxt.Dconv
-			Fatalf("naddr: OADDR %v (from %v)", Ctxt.Dconv(a), Oconv(int(n.Left.Op), 0))
+			Fatalf("naddr: OADDR %v (from %v)", Ctxt.Dconv(a), Oconv(n.Left.Op, 0))
 		}
 		a.Type = obj.TYPE_ADDR
 
diff --git a/src/cmd/compile/internal/gc/order.go b/src/cmd/compile/internal/gc/order.go
index da81f2d..b9e4b78 100644
--- a/src/cmd/compile/internal/gc/order.go
+++ b/src/cmd/compile/internal/gc/order.go
@@ -174,7 +174,7 @@
 		return a
 	}
 
-	Fatalf("ordersafeexpr %v", Oconv(int(n.Op), 0))
+	Fatalf("ordersafeexpr %v", Oconv(n.Op, 0))
 	return nil // not reached
 }
 
@@ -427,7 +427,7 @@
 func ordermapassign(n *Node, order *Order) {
 	switch n.Op {
 	default:
-		Fatalf("ordermapassign %v", Oconv(int(n.Op), 0))
+		Fatalf("ordermapassign %v", Oconv(n.Op, 0))
 
 	case OAS:
 		order.out = append(order.out, n)
@@ -486,7 +486,7 @@
 
 	switch n.Op {
 	default:
-		Fatalf("orderstmt %v", Oconv(int(n.Op), 0))
+		Fatalf("orderstmt %v", Oconv(n.Op, 0))
 
 	case OVARKILL, OVARLIVE:
 		order.out = append(order.out, n)
@@ -802,7 +802,7 @@
 		var r *Node
 		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
 			if it.N().Op != OXCASE {
-				Fatalf("order select case %v", Oconv(int(it.N().Op), 0))
+				Fatalf("order select case %v", Oconv(it.N().Op, 0))
 			}
 			r = it.N().Left
 			setlineno(it.N())
@@ -815,7 +815,7 @@
 			if r != nil {
 				switch r.Op {
 				default:
-					Yyerror("unknown op in select %v", Oconv(int(r.Op), 0))
+					Yyerror("unknown op in select %v", Oconv(r.Op, 0))
 					Dump("select case", r)
 
 					// If this is case x := <-ch or case x, y := <-ch, the case has
@@ -957,7 +957,7 @@
 		orderexpr(&n.Left, order, nil)
 		for it := nodeSeqIterate(n.List); !it.Done(); it.Next() {
 			if it.N().Op != OXCASE {
-				Fatalf("order switch case %v", Oconv(int(it.N().Op), 0))
+				Fatalf("order switch case %v", Oconv(it.N().Op, 0))
 			}
 			orderexprlistinplace(it.N().List, order)
 			orderblockNodes(&it.N().Nbody)
diff --git a/src/cmd/compile/internal/gc/pgen.go b/src/cmd/compile/internal/gc/pgen.go
index 963d59f..c41d7fe 100644
--- a/src/cmd/compile/internal/gc/pgen.go
+++ b/src/cmd/compile/internal/gc/pgen.go
@@ -90,7 +90,7 @@
 		Fatalf("gvardef nil")
 	}
 	if n.Op != ONAME {
-		Yyerror("gvardef %v; %v", Oconv(int(n.Op), obj.FmtSharp), n)
+		Yyerror("gvardef %v; %v", Oconv(n.Op, obj.FmtSharp), n)
 		return
 	}
 
diff --git a/src/cmd/compile/internal/gc/racewalk.go b/src/cmd/compile/internal/gc/racewalk.go
index 433c0b0..b25f6d3 100644
--- a/src/cmd/compile/internal/gc/racewalk.go
+++ b/src/cmd/compile/internal/gc/racewalk.go
@@ -135,7 +135,7 @@
 
 	switch n.Op {
 	default:
-		Fatalf("instrument: unknown node type %v", Oconv(int(n.Op), 0))
+		Fatalf("instrument: unknown node type %v", Oconv(n.Op, 0))
 
 	case OAS, OASWB, OAS2FUNC:
 		instrumentnode(&n.Left, init, 1, 0)
@@ -364,13 +364,13 @@
 		OAS2RECV,
 		OAS2MAPR,
 		OASOP:
-		Yyerror("instrument: %v must be lowered by now", Oconv(int(n.Op), 0))
+		Yyerror("instrument: %v must be lowered by now", Oconv(n.Op, 0))
 
 		goto ret
 
 		// impossible nodes: only appear in backend.
 	case ORROTC, OEXTEND:
-		Yyerror("instrument: %v cannot exist now", Oconv(int(n.Op), 0))
+		Yyerror("instrument: %v cannot exist now", Oconv(n.Op, 0))
 		goto ret
 
 	case OGETG:
diff --git a/src/cmd/compile/internal/gc/select.go b/src/cmd/compile/internal/gc/select.go
index 1319efb..7c0afb7 100644
--- a/src/cmd/compile/internal/gc/select.go
+++ b/src/cmd/compile/internal/gc/select.go
@@ -18,7 +18,7 @@
 		ncase = it.N()
 		setlineno(ncase)
 		if ncase.Op != OXCASE {
-			Fatalf("typecheckselect %v", Oconv(int(ncase.Op), 0))
+			Fatalf("typecheckselect %v", Oconv(ncase.Op, 0))
 		}
 
 		if nodeSeqLen(ncase.List) == 0 {
@@ -121,7 +121,7 @@
 			var ch *Node
 			switch n.Op {
 			default:
-				Fatalf("select %v", Oconv(int(n.Op), 0))
+				Fatalf("select %v", Oconv(n.Op, 0))
 
 				// ok already
 			case OSEND:
@@ -218,7 +218,7 @@
 		setNodeSeq(&r.Ninit, cas.Ninit)
 		switch n.Op {
 		default:
-			Fatalf("select %v", Oconv(int(n.Op), 0))
+			Fatalf("select %v", Oconv(n.Op, 0))
 
 			// if selectnbsend(c, v) { body } else { default body }
 		case OSEND:
@@ -284,7 +284,7 @@
 		} else {
 			switch n.Op {
 			default:
-				Fatalf("select %v", Oconv(int(n.Op), 0))
+				Fatalf("select %v", Oconv(n.Op, 0))
 
 				// selectsend(sel *byte, hchan *chan any, elem *any) (selected bool);
 			case OSEND:
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index df5e969..66792e7 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -2328,7 +2328,7 @@
 		// want to set it here.
 	case OCALLINTER:
 		if fn.Op != ODOTINTER {
-			Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", Oconv(int(fn.Op), 0))
+			Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", Oconv(fn.Op, 0))
 		}
 		i := s.expr(fn.Left)
 		itab := s.newValue1(ssa.OpITab, Types[TUINTPTR], i)
@@ -2558,7 +2558,7 @@
 		return s.call(n, callNormal)
 
 	default:
-		s.Unimplementedf("unhandled addr %v", Oconv(int(n.Op), 0))
+		s.Unimplementedf("unhandled addr %v", Oconv(n.Op, 0))
 		return nil
 	}
 }
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 24ee47b..96abb3b 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1376,9 +1376,9 @@
 	}
 	switch n.Op {
 	case ONAME:
-		fmt.Printf("%v %v G%d %v width=%d\n", Oconv(int(n.Op), 0), n.Sym, n.Name.Vargen, n.Type, w)
+		fmt.Printf("%v %v G%d %v width=%d\n", Oconv(n.Op, 0), n.Sym, n.Name.Vargen, n.Type, w)
 	case OTYPE:
-		fmt.Printf("%v %v width=%d\n", Oconv(int(n.Op), 0), n.Type, w)
+		fmt.Printf("%v %v width=%d\n", Oconv(n.Op, 0), n.Type, w)
 	}
 }
 
@@ -1459,7 +1459,7 @@
 	}
 
 	s := fmt_
-	Yyerror("illegal types for operand: %v%s", Oconv(int(op), 0), s)
+	Yyerror("illegal types for operand: %v%s", Oconv(op, 0), s)
 }
 
 // iterator to walk a structure declaration
@@ -1601,7 +1601,7 @@
 	case OGE:
 		return OLT
 	}
-	Fatalf("brcom: no com for %v\n", Oconv(int(op), 0))
+	Fatalf("brcom: no com for %v\n", Oconv(op, 0))
 	return op
 }
 
@@ -1622,7 +1622,7 @@
 	case OGE:
 		return OLE
 	}
-	Fatalf("brrev: no rev for %v\n", Oconv(int(op), 0))
+	Fatalf("brrev: no rev for %v\n", Oconv(op, 0))
 	return op
 }
 
diff --git a/src/cmd/compile/internal/gc/swt.go b/src/cmd/compile/internal/gc/swt.go
index 9870614..137be94 100644
--- a/src/cmd/compile/internal/gc/swt.go
+++ b/src/cmd/compile/internal/gc/swt.go
@@ -349,7 +349,7 @@
 		n := it.N()
 		setlineno(n)
 		if n.Op != OXCASE {
-			Fatalf("casebody %v", Oconv(int(n.Op), 0))
+			Fatalf("casebody %v", Oconv(n.Op, 0))
 		}
 		n.Op = OCASE
 		needvar := nodeSeqLen(n.List) != 1 || nodeSeqFirst(n.List).Op == OLITERAL
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index ea61322..e5d5a59 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -273,7 +273,7 @@
 	default:
 		Dump("typecheck", n)
 
-		Fatalf("typecheck %v", Oconv(int(n.Op), 0))
+		Fatalf("typecheck %v", Oconv(n.Op, 0))
 
 	// names
 	case OLITERAL:
@@ -592,7 +592,7 @@
 				aop = assignop(l.Type, r.Type, nil)
 				if aop != 0 {
 					if Isinter(r.Type) && !Isinter(l.Type) && algtype1(l.Type, nil) == ANOEQ {
-						Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(int(op), 0), typekind(l.Type))
+						Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(op, 0), typekind(l.Type))
 						n.Type = nil
 						return
 					}
@@ -614,7 +614,7 @@
 				aop = assignop(r.Type, l.Type, nil)
 				if aop != 0 {
 					if Isinter(l.Type) && !Isinter(r.Type) && algtype1(r.Type, nil) == ANOEQ {
-						Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(int(op), 0), typekind(r.Type))
+						Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(op, 0), typekind(r.Type))
 						n.Type = nil
 						return
 					}
@@ -645,7 +645,7 @@
 		}
 
 		if !okfor[op][et] {
-			Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(int(op), 0), typekind(t))
+			Yyerror("invalid operation: %v (operator %v not defined on %s)", n, Oconv(op, 0), typekind(t))
 			n.Type = nil
 			return
 		}
@@ -753,7 +753,7 @@
 			return
 		}
 		if !okfor[n.Op][t.Etype] {
-			Yyerror("invalid operation: %v %v", Oconv(int(n.Op), 0), t)
+			Yyerror("invalid operation: %v %v", Oconv(n.Op, 0), t)
 			n.Type = nil
 			return
 		}
@@ -1369,7 +1369,7 @@
 
 	case OCAP, OLEN, OREAL, OIMAG:
 		ok |= Erv
-		if !onearg(n, "%v", Oconv(int(n.Op), 0)) {
+		if !onearg(n, "%v", Oconv(n.Op, 0)) {
 			n.Type = nil
 			return
 		}
@@ -1438,7 +1438,7 @@
 		break OpSwitch
 
 	badcall1:
-		Yyerror("invalid argument %v for %v", Nconv(n.Left, obj.FmtLong), Oconv(int(n.Op), 0))
+		Yyerror("invalid argument %v for %v", Nconv(n.Left, obj.FmtLong), Oconv(n.Op, 0))
 		n.Type = nil
 		return
 
@@ -1519,7 +1519,7 @@
 		break OpSwitch
 
 	case OCLOSE:
-		if !onearg(n, "%v", Oconv(int(n.Op), 0)) {
+		if !onearg(n, "%v", Oconv(n.Op, 0)) {
 			n.Type = nil
 			return
 		}
@@ -2356,19 +2356,19 @@
 		return true
 	}
 	if nodeSeqLen(n.List) == 0 {
-		Yyerror("missing argument to %v - %v", Oconv(int(n.Op), 0), n)
+		Yyerror("missing argument to %v - %v", Oconv(n.Op, 0), n)
 		return false
 	}
 
 	n.Left = nodeSeqFirst(n.List)
 	if nodeSeqLen(n.List) == 1 {
-		Yyerror("missing argument to %v - %v", Oconv(int(n.Op), 0), n)
+		Yyerror("missing argument to %v - %v", Oconv(n.Op, 0), n)
 		setNodeSeq(&n.List, nil)
 		return false
 	}
 
 	if nodeSeqLen(n.List) > 2 {
-		Yyerror("too many arguments to %v - %v", Oconv(int(n.Op), 0), n)
+		Yyerror("too many arguments to %v - %v", Oconv(n.Op, 0), n)
 		setNodeSeq(&n.List, nil)
 		return false
 	}
@@ -2744,7 +2744,7 @@
 		if call != nil {
 			Yyerror("invalid use of ... in call to %v", call)
 		} else {
-			Yyerror("invalid use of ... in %v", Oconv(int(op), 0))
+			Yyerror("invalid use of ... in %v", Oconv(op, 0))
 		}
 	}
 
@@ -2764,7 +2764,7 @@
 				Yyerror("not enough arguments in call to %v", call)
 			}
 		} else {
-			Yyerror("not enough arguments to %v", Oconv(int(op), 0))
+			Yyerror("not enough arguments to %v", Oconv(op, 0))
 		}
 		if n != nil {
 			n.Diag = 1
@@ -2777,7 +2777,7 @@
 	if call != nil {
 		Yyerror("too many arguments in call to %v", call)
 	} else {
-		Yyerror("too many arguments to %v", Oconv(int(op), 0))
+		Yyerror("too many arguments to %v", Oconv(op, 0))
 	}
 	goto out
 }
@@ -3679,7 +3679,7 @@
 
 	switch n.Op {
 	default:
-		Fatalf("typecheckdef %v", Oconv(int(n.Op), 0))
+		Fatalf("typecheckdef %v", Oconv(n.Op, 0))
 
 		// not really syms
 	case OGOTO, OLABEL:
diff --git a/src/cmd/compile/internal/gc/unsafe.go b/src/cmd/compile/internal/gc/unsafe.go
index 8884374..f775d6b 100644
--- a/src/cmd/compile/internal/gc/unsafe.go
+++ b/src/cmd/compile/internal/gc/unsafe.go
@@ -87,7 +87,7 @@
 
 			default:
 				Dump("unsafenmagic", r)
-				Fatalf("impossible %v node after dot insertion", Oconv(int(r1.Op), obj.FmtSharp))
+				Fatalf("impossible %v node after dot insertion", Oconv(r1.Op, obj.FmtSharp))
 				goto bad
 			}
 		}
diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go
index a63387a..9e5e26b 100644
--- a/src/cmd/compile/internal/gc/walk.go
+++ b/src/cmd/compile/internal/gc/walk.go
@@ -163,7 +163,7 @@
 		if n.Op == ONAME {
 			Yyerror("%v is not a top level statement", n.Sym)
 		} else {
-			Yyerror("%v is not a top level statement", Oconv(int(n.Op), 0))
+			Yyerror("%v is not a top level statement", Oconv(n.Op, 0))
 		}
 		Dump("nottop", n)
 
@@ -1559,7 +1559,7 @@
 		// ifaceeq(i1 any-1, i2 any-2) (ret bool);
 	case OCMPIFACE:
 		if !Eqtype(n.Left.Type, n.Right.Type) {
-			Fatalf("ifaceeq %v %v %v", Oconv(int(n.Op), 0), n.Left.Type, n.Right.Type)
+			Fatalf("ifaceeq %v %v %v", Oconv(n.Op, 0), n.Left.Type, n.Right.Type)
 		}
 		var fn *Node
 		if isnilinter(n.Left.Type) {
@@ -1685,7 +1685,7 @@
 
 	// cannot happen: caller checked that lists had same length
 	if ll != nil || lr != nil {
-		Yyerror("error in shape across %v %v %v / %d %d [%s]", Hconv(nl, obj.FmtSign), Oconv(int(op), 0), Hconv(nr, obj.FmtSign), count(nl), count(nr), Curfn.Func.Nname.Sym.Name)
+		Yyerror("error in shape across %v %v %v / %d %d [%s]", Hconv(nl, obj.FmtSign), Oconv(op, 0), Hconv(nr, obj.FmtSign), count(nl), count(nr), Curfn.Func.Nname.Sym.Name)
 	}
 	return nn
 }
@@ -1930,9 +1930,9 @@
 			l1 = dumptypes(nl, "expected")
 			l2 = dumpnodetypes(lr0, "given")
 			if l != nil {
-				Yyerror("not enough arguments to %v\n%s\n%s", Oconv(int(op), 0), l1, l2)
+				Yyerror("not enough arguments to %v\n%s\n%s", Oconv(op, 0), l1, l2)
 			} else {
-				Yyerror("too many arguments to %v\n%s\n%s", Oconv(int(op), 0), l1, l2)
+				Yyerror("too many arguments to %v\n%s\n%s", Oconv(op, 0), l1, l2)
 			}
 		}
 
@@ -2205,7 +2205,7 @@
 
 func convas(n *Node, init nodesOrNodeListPtr) *Node {
 	if n.Op != OAS {
-		Fatalf("convas: not OAS %v", Oconv(int(n.Op), 0))
+		Fatalf("convas: not OAS %v", Oconv(n.Op, 0))
 	}
 
 	n.Typecheck = 1
@@ -2352,7 +2352,7 @@
 
 		switch l.Op {
 		default:
-			Fatalf("reorder3 unexpected lvalue %v", Oconv(int(l.Op), obj.FmtSharp))
+			Fatalf("reorder3 unexpected lvalue %v", Oconv(l.Op, obj.FmtSharp))
 
 		case ONAME:
 			break
@@ -3813,7 +3813,7 @@
 
 	switch n.Op {
 	default:
-		Fatalf("usefield %v", Oconv(int(n.Op), 0))
+		Fatalf("usefield %v", Oconv(n.Op, 0))
 
 	case ODOT, ODOTPTR:
 		break
diff --git a/src/cmd/compile/internal/mips64/gsubr.go b/src/cmd/compile/internal/mips64/gsubr.go
index c0ed636..caa4a61 100644
--- a/src/cmd/compile/internal/mips64/gsubr.go
+++ b/src/cmd/compile/internal/mips64/gsubr.go
@@ -148,7 +148,7 @@
 	case gc.TFLOAT32:
 		switch op {
 		default:
-			gc.Fatalf("ginscmp: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)
+			gc.Fatalf("ginscmp: no entry for op=%v type=%v", gc.Oconv(op, 0), t)
 
 		case gc.OEQ,
 			gc.ONE:
@@ -165,7 +165,7 @@
 	case gc.TFLOAT64:
 		switch op {
 		default:
-			gc.Fatalf("ginscmp: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)
+			gc.Fatalf("ginscmp: no entry for op=%v type=%v", gc.Oconv(op, 0), t)
 
 		case gc.OEQ,
 			gc.ONE:
@@ -715,7 +715,7 @@
 	a := int(obj.AXXX)
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(op, 0), t)
 
 	case OEQ_ | gc.TBOOL,
 		OEQ_ | gc.TINT8,
diff --git a/src/cmd/compile/internal/ppc64/gsubr.go b/src/cmd/compile/internal/ppc64/gsubr.go
index 71ae7e3..3ec81cd 100644
--- a/src/cmd/compile/internal/ppc64/gsubr.go
+++ b/src/cmd/compile/internal/ppc64/gsubr.go
@@ -711,7 +711,7 @@
 	a := int(obj.AXXX)
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("optoas: no entry for op=%v type=%v", gc.Oconv(op, 0), t)
 
 	case OEQ_ | gc.TBOOL,
 		OEQ_ | gc.TINT8,
diff --git a/src/cmd/compile/internal/x86/cgen64.go b/src/cmd/compile/internal/x86/cgen64.go
index 8bb7d37..e59784b 100644
--- a/src/cmd/compile/internal/x86/cgen64.go
+++ b/src/cmd/compile/internal/x86/cgen64.go
@@ -19,12 +19,12 @@
 	if res.Op != gc.OINDREG && res.Op != gc.ONAME {
 		gc.Dump("n", n)
 		gc.Dump("res", res)
-		gc.Fatalf("cgen64 %v of %v", gc.Oconv(int(n.Op), 0), gc.Oconv(int(res.Op), 0))
+		gc.Fatalf("cgen64 %v of %v", gc.Oconv(n.Op, 0), gc.Oconv(res.Op, 0))
 	}
 
 	switch n.Op {
 	default:
-		gc.Fatalf("cgen64 %v", gc.Oconv(int(n.Op), 0))
+		gc.Fatalf("cgen64 %v", gc.Oconv(n.Op, 0))
 
 	case gc.OMINUS:
 		gc.Cgen(n.Left, res)
@@ -531,7 +531,7 @@
 	var br *obj.Prog
 	switch op {
 	default:
-		gc.Fatalf("cmp64 %v %v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("cmp64 %v %v", gc.Oconv(op, 0), t)
 
 		// cmp hi
 	// jne L
diff --git a/src/cmd/compile/internal/x86/ggen.go b/src/cmd/compile/internal/x86/ggen.go
index f3481c3..fccb553 100644
--- a/src/cmd/compile/internal/x86/ggen.go
+++ b/src/cmd/compile/internal/x86/ggen.go
@@ -661,7 +661,7 @@
 	switch n.Op {
 	default:
 		gc.Dump("cgen_floatsse", n)
-		gc.Fatalf("cgen_floatsse %v", gc.Oconv(int(n.Op), 0))
+		gc.Fatalf("cgen_floatsse %v", gc.Oconv(n.Op, 0))
 		return
 
 	case gc.OMINUS,
diff --git a/src/cmd/compile/internal/x86/gsubr.go b/src/cmd/compile/internal/x86/gsubr.go
index 4fd6680..555606c 100644
--- a/src/cmd/compile/internal/x86/gsubr.go
+++ b/src/cmd/compile/internal/x86/gsubr.go
@@ -91,7 +91,7 @@
 	a := obj.AXXX
 	switch uint32(op)<<16 | uint32(gc.Simtype[t.Etype]) {
 	default:
-		gc.Fatalf("optoas: no entry %v-%v", gc.Oconv(int(op), 0), t)
+		gc.Fatalf("optoas: no entry %v-%v", gc.Oconv(op, 0), t)
 
 	case OADDR_ | gc.TPTR32:
 		a = x86.ALEAL
@@ -454,7 +454,7 @@
 	if !gc.Thearch.Use387 {
 		switch uint32(op)<<16 | uint32(et) {
 		default:
-			gc.Fatalf("foptoas-sse: no entry %v-%v", gc.Oconv(int(op), 0), t)
+			gc.Fatalf("foptoas-sse: no entry %v-%v", gc.Oconv(op, 0), t)
 
 		case OCMP_ | gc.TFLOAT32:
 			a = x86.AUCOMISS
@@ -587,7 +587,7 @@
 		return x86.AFCHS
 	}
 
-	gc.Fatalf("foptoas %v %v %#x", gc.Oconv(int(op), 0), t, flg)
+	gc.Fatalf("foptoas %v %v %#x", gc.Oconv(op, 0), t, flg)
 	return 0
 }