cmd/compile: minor cleanups

Some minor scoping cleanups found by a very old version of grind.

Change-Id: I1d373817586445fc87e38305929097b652696fdd
Reviewed-on: https://go-review.googlesource.com/21064
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

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

@@ -110,22 +110,21 @@ func cgen_wb(n, res *Node, wb bool) {
 			return
 		}
 
-		var f int
 		if res.Ullman < UINF {
 			if Complexop(n, res) {
 				Complexgen(n, res)
 				return
 			}
 
-			f = 1 // gen thru register
+			f := true // gen thru register
 			switch n.Op {
 			case OLITERAL:
 				if Smallintconst(n) {
-					f = 0
+					f = false
 				}
 
 			case OREGISTER:
-				f = 0
+				f = false
 			}
 
 			if !Iscomplex[n.Type.Etype] && Ctxt.Arch.Regsize == 8 && !wb {
@@ -133,7 +132,7 @@ func cgen_wb(n, res *Node, wb bool) {
 				var addr obj.Addr
 				if Thearch.Sudoaddable(a, res, &addr) {
 					var p1 *obj.Prog
-					if f != 0 {
+					if f {
 						var n2 Node
 						Regalloc(&n2, res.Type, nil)
 						Cgen(n, &n2)

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

@@ -599,7 +599,6 @@ var keywords = map[string]int32{
 }
 
 func (l *lexer) number(c rune) {
-	var str string
 	cp := &lexbuf
 	cp.Reset()
 
@@ -643,6 +642,7 @@ func (l *lexer) number(c rune) {
 	}
 
 	// unless we have a hex number, parse fractional part or exponent, if any
+	var str string
 	if !isInt {
 		isInt = true // assume int unless proven otherwise
 

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

@@ -3133,9 +3133,7 @@ func (p *parser) hidden_funarg() *Node {
 		s3 := p.hidden_type()
 		s4 := p.oliteral()
 
-		var t *Type
+		t := typ(TARRAY)
-
-		t = typ(TARRAY)
 		t.Bound = -1
 		t.Type = s3
 
@@ -3159,19 +3157,16 @@ func (p *parser) hidden_structdcl() *Node {
 	s2 := p.hidden_type()
 	s3 := p.oliteral()
 
-	var s *Sym
-	var pkg *Pkg
-
 	var ss *Node
 	if s1 != nil && s1.Name != "?" {
 		ss = Nod(ODCLFIELD, newname(s1), typenod(s2))
 		ss.SetVal(s3)
 	} else {
-		s = s2.Sym
+		s := s2.Sym
 		if s == nil && Isptr[s2.Etype] {
 			s = s2.Type.Sym
 		}
-		pkg = importpkg
+		pkg := importpkg
 		if s1 != nil {
 			pkg = s1.Pkg
 		}

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

@@ -1286,7 +1286,6 @@ loop2:
 	}
 	nregion = 0
 	region = region[:0]
-	var rgp *Rgn
 	for f := firstf; f != nil; f = f.Link {
 		r := f.Data.(*Reg)
 		for z := 0; z < BITS; z++ {
@@ -1347,16 +1346,14 @@ loop2:
 	if Debug['R'] != 0 && Debug['v'] != 0 {
 		fmt.Printf("\nregisterizing\n")
 	}
-	var usedreg uint64
-	var vreg uint64
 	for i := 0; i < nregion; i++ {
-		rgp = &region[i]
+		rgp := &region[i]
 		if Debug['R'] != 0 && Debug['v'] != 0 {
 			fmt.Printf("region %d: cost %d varno %d enter %d\n", i, rgp.cost, rgp.varno, rgp.enter.Prog.Pc)
 		}
 		bit = blsh(uint(rgp.varno))
-		usedreg = paint2(rgp.enter, int(rgp.varno), 0)
+		usedreg := paint2(rgp.enter, int(rgp.varno), 0)
-		vreg = allreg(usedreg, rgp)
+		vreg := allreg(usedreg, rgp)
 		if rgp.regno != 0 {
 			if Debug['R'] != 0 && Debug['v'] != 0 {
 				v := &vars[rgp.varno]

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

@@ -568,16 +568,14 @@ func structlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 		index := r.Left
 		value := r.Right
 
-		var a *Node
-
 		switch value.Op {
 		case OARRAYLIT:
 			if value.Type.Bound < 0 {
 				if pass == 1 && ctxt != 0 {
-					a = NodSym(ODOT, var_, index.Sym)
+					a := NodSym(ODOT, var_, index.Sym)
 					slicelit(ctxt, value, a, init)
 				} else if pass == 2 && ctxt == 0 {
-					a = NodSym(ODOT, var_, index.Sym)
+					a := NodSym(ODOT, var_, index.Sym)
 					slicelit(ctxt, value, a, init)
 				} else if pass == 3 {
 					break
@@ -585,12 +583,12 @@ func structlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 				continue
 			}
 
-			a = NodSym(ODOT, var_, index.Sym)
+			a := NodSym(ODOT, var_, index.Sym)
 			arraylit(ctxt, pass, value, a, init)
 			continue
 
 		case OSTRUCTLIT:
-			a = NodSym(ODOT, var_, index.Sym)
+			a := NodSym(ODOT, var_, index.Sym)
 			structlit(ctxt, pass, value, a, init)
 			continue
 		}
@@ -605,7 +603,7 @@ func structlit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 
 		// build list of var.field = expr
 		setlineno(value)
-		a = NodSym(ODOT, var_, index.Sym)
+		a := NodSym(ODOT, var_, index.Sym)
 
 		a = Nod(OAS, a, value)
 		a = typecheck(a, Etop)
@@ -632,16 +630,14 @@ func arraylit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 		index := r.Left
 		value := r.Right
 
-		var a *Node
-
 		switch value.Op {
 		case OARRAYLIT:
 			if value.Type.Bound < 0 {
 				if pass == 1 && ctxt != 0 {
-					a = Nod(OINDEX, var_, index)
+					a := Nod(OINDEX, var_, index)
 					slicelit(ctxt, value, a, init)
 				} else if pass == 2 && ctxt == 0 {
-					a = Nod(OINDEX, var_, index)
+					a := Nod(OINDEX, var_, index)
 					slicelit(ctxt, value, a, init)
 				} else if pass == 3 {
 					break
@@ -649,12 +645,12 @@ func arraylit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 				continue
 			}
 
-			a = Nod(OINDEX, var_, index)
+			a := Nod(OINDEX, var_, index)
 			arraylit(ctxt, pass, value, a, init)
 			continue
 
 		case OSTRUCTLIT:
-			a = Nod(OINDEX, var_, index)
+			a := Nod(OINDEX, var_, index)
 			structlit(ctxt, pass, value, a, init)
 			continue
 		}
@@ -669,7 +665,7 @@ func arraylit(ctxt int, pass int, n *Node, var_ *Node, init *Nodes) {
 
 		// build list of var[index] = value
 		setlineno(value)
-		a = Nod(OINDEX, var_, index)
+		a := Nod(OINDEX, var_, index)
 
 		a = Nod(OAS, a, value)
 		a = typecheck(a, Etop)

src/cmd/compile/internal/ssa/config.go

@@ -178,8 +178,7 @@ func (c *Config) Warnl(line int32, msg string, args ...interface{}) { c.fe.Warnl
 func (c *Config) Debug_checknil() bool                              { return c.fe.Debug_checknil() }
 
 func (c *Config) logDebugHashMatch(evname, name string) {
-	var file *os.File
+	file := c.logfiles[evname]
-	file = c.logfiles[evname]
 	if file == nil {
 		file = os.Stdout
 		tmpfile := os.Getenv("GSHS_LOGFILE")

src/cmd/compile/internal/ssa/layout.go

@@ -96,7 +96,6 @@ blockloop:
 				continue blockloop
 			}
 		}
-		b.Fatalf("no block available for layout")
 	}
 	f.Blocks = order
 }

src/cmd/compile/internal/ssa/regalloc.go

@@ -679,9 +679,8 @@ func (s *regAllocState) regalloc(f *Func) {
 				}
 				a := v.Args[idx]
 				m := s.values[a.ID].regs &^ phiUsed
-				var r register
 				if m != 0 {
-					r = pickReg(m)
+					r := pickReg(m)
 					s.freeReg(r)
 					phiUsed |= regMask(1) << r
 					phiRegs = append(phiRegs, r)