all: unindent some if bodies by exiting early

All of these had a return or break in the else body, so flipping the
condition means we can unindent and simplify.

Change-Id: If93e97504480d18a0dac3f2c8ffe57ab8bcb929c
Reviewed-on: https://go-review.googlesource.com/74190
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

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

@@ -1056,18 +1056,17 @@ func parName(f *types.Field, numbered bool) string {
 	// Take the name from the original, lest we substituted it with ~r%d or ~b%d.
 	// ~r%d is a (formerly) unnamed result.
 	if asNode(f.Nname) != nil {
-		if asNode(f.Nname).Orig != nil {
-			s = asNode(f.Nname).Orig.Sym
-			if s != nil && s.Name[0] == '~' {
-				if s.Name[1] == 'r' { // originally an unnamed result
-					return "" // s = nil
-				} else if s.Name[1] == 'b' { // originally the blank identifier _
-					return "_" // belongs to localpkg
-				}
-			}
-		} else {
+		if asNode(f.Nname).Orig == nil {
 			return "" // s = nil
 		}
+		s = asNode(f.Nname).Orig.Sym
+		if s != nil && s.Name[0] == '~' {
+			if s.Name[1] == 'r' { // originally an unnamed result
+				return "" // s = nil
+			} else if s.Name[1] == 'b' { // originally the blank identifier _
+				return "_" // belongs to localpkg
+			}
+		}
 	}
 
 	if s == nil {

src/cmd/link/internal/ld/data.go

@@ -2049,13 +2049,12 @@ func (ctxt *Link) address() {
 	// their section Vaddr, using n for index
 	n := 1
 	for _, sect := range Segtext.Sections[1:] {
-		if sect.Name == ".text" {
-			symname := fmt.Sprintf("runtime.text.%d", n)
-			ctxt.xdefine(symname, sym.STEXT, int64(sect.Vaddr))
-			n++
-		} else {
+		if sect.Name != ".text" {
 			break
 		}
+		symname := fmt.Sprintf("runtime.text.%d", n)
+		ctxt.xdefine(symname, sym.STEXT, int64(sect.Vaddr))
+		n++
 	}
 
 	ctxt.xdefine("runtime.rodata", sym.SRODATA, int64(rodata.Vaddr))

src/mime/mediatype.go

@@ -187,18 +187,18 @@ func ParseMediaType(v string) (mediatype string, params map[string]string, err e
 				continue
 			}
 			encodedPart := simplePart + "*"
-			if v, ok := pieceMap[encodedPart]; ok {
-				valid = true
-				if n == 0 {
-					if decv, ok := decode2231Enc(v); ok {
-						buf.WriteString(decv)
-					}
-				} else {
-					decv, _ := percentHexUnescape(v)
+			v, ok := pieceMap[encodedPart]
+			if !ok {
+				break
+			}
+			valid = true
+			if n == 0 {
+				if decv, ok := decode2231Enc(v); ok {
 					buf.WriteString(decv)
 				}
 			} else {
-				break
+				decv, _ := percentHexUnescape(v)
+				buf.WriteString(decv)
 			}
 		}
 		if valid {

src/reflect/value.go

@@ -1074,15 +1074,14 @@ func (v Value) MapIndex(key Value) Value {
 	typ := tt.elem
 	fl := (v.flag | key.flag).ro()
 	fl |= flag(typ.Kind())
-	if ifaceIndir(typ) {
-		// Copy result so future changes to the map
-		// won't change the underlying value.
-		c := unsafe_New(typ)
-		typedmemmove(typ, c, e)
-		return Value{typ, c, fl | flagIndir}
-	} else {
+	if !ifaceIndir(typ) {
 		return Value{typ, *(*unsafe.Pointer)(e), fl}
 	}
+	// Copy result so future changes to the map
+	// won't change the underlying value.
+	c := unsafe_New(typ)
+	typedmemmove(typ, c, e)
+	return Value{typ, c, fl | flagIndir}
 }
 
 // MapKeys returns a slice containing all the keys present in the map,

src/regexp/exec.go

@@ -338,15 +338,14 @@ func (m *machine) onepass(i input, pos, ncap int) bool {
 	if pos == 0 && syntax.EmptyOp(inst.Arg)&^flag == 0 &&
 		len(m.re.prefix) > 0 && i.canCheckPrefix() {
 		// Match requires literal prefix; fast search for it.
-		if i.hasPrefix(m.re) {
-			pos += len(m.re.prefix)
-			r, width = i.step(pos)
-			r1, width1 = i.step(pos + width)
-			flag = i.context(pos)
-			pc = int(m.re.prefixEnd)
-		} else {
+		if !i.hasPrefix(m.re) {
 			return m.matched
 		}
+		pos += len(m.re.prefix)
+		r, width = i.step(pos)
+		r1, width1 = i.step(pos + width)
+		flag = i.context(pos)
+		pc = int(m.re.prefixEnd)
 	}
 	for {
 		inst = m.op.Inst[pc]

src/text/tabwriter/tabwriter.go

@@ -352,20 +352,19 @@ func (b *Writer) format(pos0 int, line0, line1 int) (pos int) {
 		discardable := true // true if all cells in this column are empty and "soft"
 		for ; this < line1; this++ {
 			line = b.lines[this]
-			if column < len(line)-1 {
-				// cell exists in this column
-				c := line[column]
-				// update width
-				if w := c.width + b.padding; w > width {
-					width = w
-				}
-				// update discardable
-				if c.width > 0 || c.htab {
-					discardable = false
-				}
-			} else {
+			if column >= len(line)-1 {
 				break
 			}
+			// cell exists in this column
+			c := line[column]
+			// update width
+			if w := c.width + b.padding; w > width {
+				width = w
+			}
+			// update discardable
+			if c.width > 0 || c.htab {
+				discardable = false
+			}
 		}
 		// column block end